Post by Bill Von Sennet on Aug 22, 2008 22:05:31 GMT -5
Tom Goodrick
Flying Singles
« on: Mar 12th, 2007, 3:25pm »
Single engne aircraft are what everyone starts with when learning to fly. Not even a student enrolled in an aviation school for airline pilots starts with more than one engine. There is enough to learn about flying a single engine plane when you first start without worrying about the speed and complexities of multi-engine aircraft.
Singles are subdivided into additional subclasses: fixed gear or retractable gear, fixed prop or constant speed prop. They have a variety of seats from one to as many as eight. They have many different engines - piston, turboprop and fanjet. Here we will only discuss piston engines. Some singles are turbocharged for flight at high altitudes and some are also pressurized so people can breath normally in the cabin. If not pressurized, you cannot descend faster than 500 fpm for long periods of time. Passengers would breath oxygen from a bag but that would not protect their ears from the decompression of a rapid descent. We make note of whther or not an aircraft is pressurized because that makes a difference in how you fly them.
The only difference in flying retractable gear aircraft is remembering to get the gear up after lifting off and to get it down before landing. Some aircraft have so much gear drag they can barely fly with heavy loads until the gear are tucked up into the wing or belly. One method of avoiding gear-up landings is to use the gear as a decelerator when you reach a low altitude near the airport after descending from cruise altitude. Then leave the gear down for the rest of the flight. Some aircraft have warning buzzers that sound if the throttle is retarded significantly while the gear is up. You must slow the airplane down enough before lowering the gear so it will not be damaged. In most cases I have installed a BASP light on my models. This is a light that is red when you are too fast. You cannot lower the gear until you slow down enough so the GASP light turns green. (GASP stands for Gear Air Speed). Usually this happens at a speed higher than the speed for lowering the flaps. (Yes, some of my aircraft have a FASP light, too). But in some cases, the designers allow the first notch of flaps to come down at a higher speed than the gear speed so you can get help from the flaps in slowing to gear speed.
A fixed gear aircraft usually has enough drag to slow down for landing by just throttling back to 1500 rpm and holding level flight for a while. With any aircraft, cruise is performed at some altitude well above the pattern altitude (800 to 1000 ft above the runway elevation). To descend you reduce power to 50% and then descend at 500 fpm if not pressurized. At or just above pattern altitude, you level off but keep the same low power until the airplane slows enough to begin final approach. dring that time you maneuver to get lined up for the approach.
Normally flaps are used to enable a steep descent without increasing the speed. But some planes have no flaps. In these planes you must do a slip to control your glide slope. The slip is done by banking one way and holding rudder for the opposite direction - just enough rudder so you do not turn and you track straight along the direction to the runway. This will be demonstrated in the discussions of the J-3 Cub and the Aeronca Champ.
If the plane has a fixed pitch prop, your only power control is the throttle and power is measured by the tachometer showing rpm. Having a fuel flow gauge is handy because that too is an effective measure of power. You will note that the rpm changes without your moving the throttle if you descend or climb a bit. This is an effect of loading the prop. Aircraft are generally set up so full throttle will give adequate power for takeoff. But at high elevations you may have to lean the mixture before you can even keep the engine running and make a takeoff. You should look at the fuel flow gauge and lean enough to maximize the fuel flow which maximizes the power. If there is no fuel flow gauge, maximize rpm with the mixture during the takeoff run at high elevations. Normal cruise rpm in any airplane is 2400 rpm. Normal low-speed rpm for descent or before making a landing approach is 1500 rpm.
If an airplane has a constant speed prop, it means you should be able to set the rpm using the prop control independently of the throttle setting The throttle setting then changes the manifold pressure (in inches of mercury from 15 to 30.) Any power setting consists of both a throttle adjustment and a prop adustment. If in doubt, push all levers forward for takeoff and then set max throttle and 2500 rpm for climb, 24 inches and 2400 rpm for cruise and 15 inches and 2100 rpm for descent. In many cases I provide a power Gauge that uses the fuel flow as the basis for showing power in percent max. 75% is normally used for cruise and 50% for descent.
Aircraft that have turbocharged engines (such as the Mooney Bravo and Piper Mirage) will show much higher manifold pressures than the "normally aspirated" engines. This makes setting power very confusing. I have put Power gauges in these aircraft to make it easy. This is a new gauge also included in many real aircraft that have fuel management computers.
In pressurized aircraft, I include a cabin altimeter just like the real aircraft would have. this will show the cabin is at 8,000 ft when the aircraft is at cruise altitude. This is done mainly so you have a littl piloting challenge during the descent. The pressurization system for most small aircraft uses engine or turbine pressure (all are turbocharged) to "pump up" the cabin. If you cut to idle when making a descent, the cabin altitude will drop sharply causing injusry. If normally managed with moderate power reuctions over time, you can descend the aircraft at up to 2000 ft per minute with the cabin "descending" only at 500 ft per minute. The faster and higher a plane flies, the more work the pilot must do.
« Last Edit: Mar 12th, 2007, 4:12pm by Tom Goodrick »
Tom Goodrick
Re: Flying Singles
« Reply #1 on: Mar 12th, 2007, 3:26pm »
Notes on flying the Piper J-3 Cub:
The Piper J-3 Cub has been one of my favorites since I learned to fly it as a kid. It was not something that inspired enthusiasm for its speed or aerobatics. But it got me up into the air to look at the world from a different perspective. I loved doing spins in it.
When I first flew the FS9 version, I was extremely dissapointed. I could not even taxi it to the runway and take off without crashing. I had no such trouble with the real J-3. Some idiot at M$ had cranked up the sensitivity to torque and p factor so much that it would flip over while taxiing when you applied throttle. In the real one you do have to give it bursts of throttle to get it moving and to keep it moving, especially on grass which was all I had to taxi, land and take off from. These problems can be reduced if you change the "Realism" settings which really have little to do with reality. They produce moire arcade-quality thrills than realism.
Set General to 100%, P-factor to 65-70%, Torque to 50%, gyro to 80% and Crash Tolerance to 70%.
Then use the FD files for the Cub from my web site. These will help greatly for takeoff, cruise, landing and spinning. I used the specs from Jane's Fighting Aircraft of World War II. Believe it or not, the J-3 helped win the war. It was used by artillery spotters. There was an instance during the Battle of the Bulge when a US general got a ride in a Cub and spotted some German troops. Then he sent US troops to a good position to counter the coming attack. The Cub was able to land and take off from roads or small fields.
The Cub was designed back in the 1930's. It has always had a gross weight of 1220 lbs. The J-3 version has a 65 hp engine. Other versions had more powerful engines. The FAA recently ruled that 1220 lbs is the limiting gross weight for Sport Aircraft you can fly in the US with a special license. The J-3 has "tandem" seating, that is, two single seats, one ahead of the other. Only the front seat has direct access to the panel and easy access to trim, mixture and carb heat controls. When flown solo, the pilot must sit in back. When a passenger is carried, the pilot usually sirts in front for a direct view of the instruments. The passenger has his own control stick, throttle (on the left side), brake and rudder pedals. The entry door is split horizontally between a solid (fabric) lower half and a plexiglass upper half. Both swing out, the lower half hanging down and the window half folding up and locking against the wing. The window can be left open during flight. This makes the plane good for aerial photography. There is a small baggage area behind the rear seat. The J-3 has no electrical system except the magnetos used for ignition. To start it, the prop must be turned by hand - very carefully. Of course in FS we just use Ctrl-E.
Here's a table of weights and CG locations. I used my XML gauges to read the weight and the CG position which is given in percent of the mean chord back from the leading edge. Because the J-3 has a rectangular wing, the chord is constant across the span. 25% is considered a good normal position for stability.
Front_000__000__000__000__120__200__200__200
Back_170__200__230__200__200__200__219__200
Bags_000__000__000__050__050__050__050__069
Xcg_24.2__26.0_27.6__30.3__28.8_27.9_28.7__29.2
GWT_921__951_981__1001__1121_1201_1220_1220
(We used the last column for the tests.)
To make the takeoff, get lined up and then advance the throttle halfway. When you have a little speed give it full throttle. Soon after that apply a little forward pressure on the stick to raise the tail (carefully). At 60 mph the plane will gently lift off. Some nose-up trim is in order so it climbs without stick force. Don't expect to rocket skyward. The climb is leisurely, normally about 450 rpm. I saw 53.21 KIAS and 517 FPM on the Landing Speed gauge during the climb. The entire climb is done at full throttle.
I checked cruise at 3000 ft and 5000 ft. Later it dawned on me that the altitudes should be 3500 and 5500 ft which are VFR altitudes. I am used to flying IFR all the time, which is required for jets and high altitude aircraft. There is theoretical condition known as "steady state" which is assummed for cruise. But in reality this is seldom achieved. in FS it can be achieved in the clear weather condition on autopilot. But the J-3 has no autopilot so we have to make many small adjustments and have a lot of patience. When you reach cruising altitude, set cruise power and trim for level flight. This is a slow process where you repeatedly make small trim adjustments. When you have the plane flying level with no stick force for several minutes, you have it in steady cruise. I remember continuously nudging the stick in the real J-3. There was no such thing as steady state. For power, I left the engine at 2200 rpm. I saw 71 mph indicated and 62.2 KIAS on the landing gauge. At 5000 ft I set 2200 rpm again and saw 74 mph indicated and 63.3 KIAS. The Garmin showed a ground speed (equals true airspeed with no wind) of 68 knots. That's about the extent of the Cub's speed. Add a head wind and fly near a highway and cars will be beating you. (But you have a more enjoyable view.)
The Cub has a tail wheel so landings are a little delicate. This type of plane is called a "taildragger". After WWII, most planes were given tricycle gear to avoid accidents during taxiing. But taildraggers are still popular where landings must be made on grass. I have given up trying to land a Cub in a crosswind in FS. The slightest later motion at the wheels during touchdown will put a wing into the ground. This is unexpected in FS because most planes in FS can skid sideways with no resistance. You can land a tri-gear aircraft crabbed 40 degrees to the runway and slide out down the centerline very peacefully.
You really need to have rudder pedals for realistic operation of a Cub because there are no flaps and the standard method of adjusting the steepness of your approach is to slip. You never dive an aircraft because it picks up too much speed. On my test flight I ended up at 5,000 ft directly over the airport where I wanted to land. I did a slip to lose altitude quickly. To do this, I lowered the left wing to hold a bank of 45 to 55 degrees and enough right rudder to keep from turning. The power was 1600 rpm, the airspeed showed 55 mph, the landing gauge showed 47.96 KIAS and -2119 FPM. That got me to 2000 feet quickly.
Then I leveled off, made a turn to line up and began a normal descent on final at 1500 rpm, 55 mph with the landing gauge showing 46.3 KIAS and -318 FPM. I landed with the tail very low at 31.00 KIAS and -106 FPM.
Jane's gives the cruise speed as 75 mph true. The stall speed is 38 mph. Those would be 65 KTAS and 33 KIAS. My landing speed was just under stall speed. That is what you want when you land a plane with a tail wheel. Otherwise the plane will fly again when you lower the tail (and increase the angle of attack).
There are two landing techniques for any tail wheel aircraft: three point and wheel landing. But my landing points to a third method in between the other two. On a three point landing, you try to get the main wheels and the tail wheel to touch at the same time with the airplane in a full stall. On a wheel landing, you touch down on the main wheels only and hold the tail wheel up as long as possible, applying some brakes very carefully. This is the recommended procedure for a DC-3. But the three-point landing is recommended for the J-3 and similar light aircraft.
The Cub is a lot of fun to fly around any local area. It is not much fun on a long cross-country. I learned that as a passenger on a flight in the winter from Anoka, Minnesota, to Brainerd, Minnesota. The J-3 does not have much of a heating system, especially for feet.
For lots of fun do spins. At about 4,000 ft, reduce the power to 1500 rpm, set carb heat on, and pull the stick back slowly. As the wings start to stall, keep the stick centered and hold full right rudder. The left wing and the nose will drop steeply and the plane will start a spin rotation. To recover let go of the rudder and push the stick forward before pulling back slowly.
Sometimes in the Cub I use the VC panel for a wide-angle perspective on landing and during taxiing. Normally I fly with just the 2D panel.
Try loading variations using the table as a guide. See what effect the various loads have on handling, especially for landing.
All aircraft that have carburated engines rather than fuel-injected engines have carburator heat controls. The J-3 has one. Any time the temperature aloft is cooler than 50 degrees (which is most of the time), you should turn on carb heat when you reduce the rpm to 1500 or less, This protects against ice forming in the venturi of the carburator where the air is cooled below ambient temperature and moisture is squeezed out. But turn off carb heat after you increase the throttle so you'll have full power available. FS9 does not seem to simulate this condition but it is good to develop this habit. Early versions of FS did a better job of simulating carb icing which has ruined the day for many pilots. It was the cause of my own one and only forced landing in a real Cessna 150.
Have fun.
« Last Edit: Mar 12th, 2007, 4:19pm by Tom Goodrick »
Tom Goodrick
Re: Flying Singles
« Reply #2 on: Mar 12th, 2007, 5:40pm »
Here are some notes on flying the Aeronca Champ. My first introduction to the Champ was in 1951 when my dad was taking lessons in one. I used to spend hours in the summer sitting by the office at the airport watching him do touch and goes. When he wasn't in the pattern, there were Bonanzas, Navions and Cessna 120's, 170's and 195's as well as Piper Cubs to watch. The Champ has made many comebacks in the past 80 years. It started in the 1930's a primary trainer. Yes, it is also one of those fighting aircraft listed in Jane's "Fighting Aircraft of WWII" as the "L-4". In the late 1960's when there were many expensive aircraft for sale (more types than available today), the Champ made a come back to a limited extent as the cheapest manufactured aircraft in version sold without an electrical system. But at the same time more expensive versions were offered with electrical systems which were needed for admission to most airports. (In the early days - up to 1970, control towers used light guns to signal airplanes approaching without radios. Today they are simply not allowed in the airspace near larger airports. But, again today the Champ is making another come back as a Light Sport aircraft.
It is similar to the J-3. Two people sit in separate seats, one in front next to the panel and one behind. There is a small space for bags behind the rear seat. A single wide door on the right side allows entry to either seat. But there are differences from the Cub. A solo pilot in the Champ must sit in the front seat where in the Cub he sits in back. The Champ has a higher empty weight and about the same gross weight. This means the payload in the Champ is less than in the Cub.
Here's how the loading works out:
Front__170__200__230__170__170__230__200
Back__000__000__000__170__170__000__150
Bags__000__000__000__000__57___100__47
Xcg__17.8__16.8__15.8_21.9_24.9__22.0__23.1
GWT_993__1023__1053_1163_1220_1153_1220
(The last column was used for the flight data discussed below.)
Taxi slowly and turn gradually. Lift off at 60 KIAS. Like the Cub, the Champ does not really rotate, it just starts lifting you into the sky. Climb at 65 KIAS with full power. I saw 62 KIAS and 532 FPM in a sustained climb.
I tested cruise at 3500 ft and at 5500 ft. At 3500 ft, 2400 rpm gave me 80 mph or 68.5 KIAS using 3.33 gph. At 5500 ft using 2500 rpm, I saw 80 mph and 69.0 KIAS using 3.48 gph.
Like the Cub, the Champ has no flaps so you need rudder pedals to fly it properly making lsips for steep approaches. During a slip to lose a lot of altitude (5500 ft to 2000 ft) I saw 83.6 KIAS and -1505 fpm on the landing gauge.
My landing was short and smooth at 42.0 KIAS and -36 FPM with a slight slip used off and on until just before touchdown.
This is a lot of fun to fly. At first the Champ was much easier to land than the Cub. I used some of the landing parameters in the Champ to help make the Cub more manageable.
Tom Goodrick
Re: Flying Singles
« Reply #3 on: Mar 14th, 2007, 12:00am »
Notes on the Cessna 172 SP AKA "Skyhawk SP"
This aircraft is new and faster version than the venerable version I flew 30 years ago and which Joe Zuzil flies today. Our 172 had a 160 hp engine and did well to cruise at 100 KTAS. Cessna still makes a plain Skyhawk with the 160 hp engine. But the SP version has a 180 hp engine and goes a bit faster. According to www.cessna.com, it cruises at 124 KTAS at 75% power at 8500 ft. They also say at the same condition it will fly 518 nm in 4.26 hours. That is demonstrating a speed of 121.6 KTAS. So we can assume it will fly somewhere beteen 122 and 124 knots true airspeed. That's a significant improvement. From the default 172 in FS9, I made FD for the old model 172I that I used to fly and for which I still have the owner's manual, a 172R which is the new 160 hp version and the 172 SP. This discussion concentrates on the SP version.
We'll look at the loading, the takoff, climb, cruise and descent conditions, make a fast landing and a slow landing and do some funny stuff including a spiral that went way outside the bounds of proper fligth and a spin that went flat, both inverted and erect, but from which we recovered. We'll discuss a new type of airspeed - Calibrated airspeed or KCAS. That is what Cessna has always given their stall speeds in. It is technically correct and practically useless. I feel very strongly they should not be allowed to do that but no one has asked me for my opinion. It is confusing. The only thing you see on the panel is IAS. You don't have time to dig out a table and try to interpolate. If they can give a table that converts CAS to IAS, they can use it themselves and publish the stall speeds in IAS. The CAS values are determined for a nominal max gross loading in a test aircraft with both a regular pitot tube and a special long pitot tube that gets the sensor well out ahead of the airflow disturmance of the wing.
In comparing the simulator to real flying, I get a little concerned that we must take some of the "game" out of it and impose a level of seriousness. 50 people each month, on average, according to the NTSB web site(www.ntsb.gov), die in small airplane accidents. On the personal side, my instructor died in a flight accident shortly after I got my license. During my training I came in one day and he was a little jumpy. He showed me why as we climbed out. He had just had a student kill the engine when they were at the low altitude where you can't do anything but land more or less straight ahead. He had managed to do a 90 degree left turn and land on part of a golf course. The plane was still there. The plane and the people were all OK except the golf course owners were unhappy. We always flew over that course in the pattern taking off to the north. Also while I was taking lessons I made takeoffs in a 150 and in a 172 for several months flying over a black hole in the forest just north of the runway where five people had died in an overloaded 172 on a hot August day. So, yes, it is a fun game and I like to try things in FS no one would dare try in real flying. That is part of what a simulator is good for. But bear in mind that real flying is serious nd requires knowledge of the many different aspects of flying.
Here is a weight chart for the C172SP. There is a lot of variation in weights used. I try to use realistic weights that include me (225 lbs these days) and "average people" of various types. 170 lb is a figure often used for an average passenger. But that is averaged through men, women and children. The average weight of a general adult male is near 200 lbs. The average weight of a military pilot is 180 lbs. (They have to keep in shape.) Many women would like to think the average weight is 120 lbs and that is probably right if you consider only college coeds. But a more realistic figure is 150 lbs. When doing meaningful weight and balance (and not being an airplane salesman) it is worthwhile to err on the high side. Filling the C172 with four real people is difficult and may mean you have to leave most the luggage and some fuel at home. When I filled it with my family of four, my oldest boy was 6 so it was fairly easy to do the job. Now it would be impossible! I will show only combined loading for each row. I cut that in half for flying so it is balanced laterally.
Front:__340__340__200__200__400__400__300__400__400
Back:__240__240__000__000__000__200__300__086__360
Bags:__000__000__000__000__000__000__000__120__000
Fuel:__42.8__008__053__053__053__053__053__053__053
Xcg:__20.8__19.9__15.2_12.9__15.0_20.0__22.6_21.9__23.5
GWT:_2460_2254_2144_1873_2344_2544__2544_2550_2704
_____________________________________*_________Fatal in 160hp on hot day.
* used for flight data, except 200/000 used for utility catagory.
The web site gives stall speeds as 53 KCAS clean and 49 KCAS with full flaps. I think I remember setting up the flight model for these speeds in KIAS. There fore we can use thes speeds to calculate takeoff speed.s. Safe takeoff speed is 1.3 x 53 = 69 KIAS. Vref on final is 1.3 x 49 = 64 KIAS.
I do not know if the same calibration chart would apply to the SP version, but, here is the table for the old 172I.
Condition__IAS__40__50__60__70__80 (all in mph)
Flaps Up__CAS_55__58__65__72__82
Flaps Dn__CAS_48__54__63__72__82
Stall speeds were 57 CAS mph clean and 49 CAS mph with full flaps.
They translate to just unde 50 IAS and just above 40 IAS. All you can see in the cockpit when you're too low and too slow is the IAS with no time to look at a table.
So, on takeoff we'll be looking for 70 KIAS to get airborn. We set the trim at 11.5 degrees. The takeoff is uneventful at full throttle. For climb you can use 80 KIAS. A convenient item with most aircraft, including the C172, is that the airspeed for climb is the same as the airspeed for a normal descent. Use 80 for descent when slow and near the airport but not yet on final. We'll do a cruising descent that is a little faster when coming down after a cross country on a smooth day. On a bumpy day, use 80-90 KIAS from cruise to the pattern.
During our steady climb, the Landing gauge shows 82.7 KIAS and 866 FPM on manual control and then 81.6 and 719 FPM on autopilot with 700 FPM set as the vertical speed. Full throttle is used in climb. as far as I know. (There could be a requirement to use 2500 rpm for the 180 hp engine.) If climbing above 4,000 ft, you will have to lean the mixture for the best fuel flow.
Here's a table of cruise values:
Altitude_RPM___GPH__KTAS__KIAS__NMPG
4500___2500__10.23___116.6__109.3__11.40
4500___2400__9.36____111.4__104.5__11.90
6500___2617__11.03___122.8__111.8__11.13
6500___2400__8.72____109.4__99.5___12.55
8500___2650__10.81___123.8__109.2__11.45 <<<Cessna Spec
8500___2400__8.22____107.7__94.9___13.10
Note that it is very effective to reduce the RPM with the throttle to fly more efficiently. Some people advocte that you lean the mixture to the lean side of peak power (peak fuel flow). But that can heat up the engine causing premature wear. It seems best to run the engine at reduced RPM but always at peak power where it operates in a safe manner.
For descent from cruise, I used 104 KIAS, 2250 RPM and got -494 FPM passing through 7,000 ft. Through 5,000 ft it was 2304 RPM, 110 KIAS and -490 FPM. I set up on a long straigh final to a busy airport at 89.9 KIAS and -660 with no flaps. I dropped 12.7 degrres flaps and landed at 63.4 KIAS and -170 FPM after rolling for a while to slow down (long runway).
Next I made a normal approach using the ILS. With 12.7 deg flaps I saw 71.6 KIAS, -396 with 1633 RPM. With 25.3 deg flaps, I saw 67.4 KIAS and -302 FPM with 1853 rpm to stay on the glideslope. With 38 deg flaps, The approach was steep and slow needing plenty of power. i saw 60.3 KIAS and -313 FPM at 1906 RPM. The landing occurred at 51.2 KIAS and -149 FPM.
With a forward CG (single pilot and nothing else) I tried a spin. It was a good thing I climbed to 5500 ft before starting. I was not carefull starting the spin and screwed up. It was going around and around all right but in a spiral not a spin. The difference is that a spiral has circular flight paths of significant diameter. The spiral allows speed to get high making recovery a touchy proposition. I managed ok but saw 120.7 KIAS and -7043 fpm rather constant during the spiral.
Next I was more careful and slowed the aircraft to near zero speed ina climb as I started the spin. This caused a quick flip to an inverted flat spin and then a change to an erect flat spin that showed the condition 0 KIAS and -8215 FPM. I managed to recover while pulling only a little less than 2.5 g's.
The Skyhawk, like many small aircraft can be flown under two sets of rules. At gross weight, it is in the Normal Category where the max g allowance is 3.8 positive. But at 300 lbs less it is in the Utility category where it can pull up to 4.4 g's. It can do many mild aerobatic maneuvers including slow-acceleration spins.
It is a fine personal transport as long as you don't carry big loads, seldom more than one other person and can afford the liesurely pace of about 115 knots.
Tom Goodrick
Re: Flying Singles
« Reply #4 on: Mar 17th, 2007, 10:54pm »
NOTES ON THE PIPER CHEROKEE 180
You can get this aircraft from my web site as part of the AI_Aircraft.zip download. That zip includes the De Havilland Dash 8 and the MD-83 that came with FS9 but as traffic aircraft (called "AI" for Artificial Intelligence). I have modified the .air files so that you can fly them. You can take a panel from the C172 for the Piper 180. Just copy the entire panel folder. I gave all aircraft in that download a flight check today and updated the download to include the latest FD improvements.
The Piper 180 used to fit in between the Cessna 172 and the 182 in capability. It has been upgraded now as the Archer with 150 lbs more gross weight and a tapered wing though the performance did not change much. The current C172SP with its 180 hp engine competes well with the old Piper 180. Like the Cessna SP, the Piper 180 has a 180 hp engine and a fixed-pitch prop. The Piper has a lower empty weight so it carries about 100 lbs more in the cabin with full tanks. The tanks are lightly smaller. It has a rectangular wing, often called a "Hershey Bar Wing" because is wings are shaped somewhat like Hershey Bars. The change to the Archer replaced those wings with sleeker-looking tapered wings. But performance did not change much. Somewhere along the way it got lower stall speeds. That probably came from new flaps in the 1980's. It has a long history. The Cherokee line (140 and 180) came out in 1960. The change to the Archer was made in 1973. Other updates came along in the 1980's and 1990's as Piper went through various ownerships. It has been manufactured almost continuously since 1960 with those few modifications. Cessna cannot say the same. Its 172 and 182 lines were shut down for a decade starting in the 1980's.
Here's the loading chart:
Front:__400___400___200___400___400___400___400___400___400
Rear:__300___300___000___000___000___000___200___280___300
Bags:__000___000___000___000___120___120___120___040___80
Fuel:__050___008___008___008___008___050___050___050___040
Xcg:__18.1__17.1___8.8____9.3___15.1__16.4___20.4___19.1__21.0
GWT: 2379__2127__1627__1827__1947__2200__2400__2400__2400*
*Used in flight for data.
I checked an old FLYING ANNUAL magazine from 1971 for the performance specs.
Nuts! I had just reset stall speeds. But in 1971 FLYING was still giving their performance data in mph, not knots. So I assume that 57 is with flaps and means 49.6 or 50 knots indicated. I expect clean stall would be about 53 KIAS. I went back to work and made that happen. I had to increase the lift coefficient for clean stall and decrease the flap lift factor. Now these numbers work.
The clean stall of 53 KIAS means V2 is 69 KIAS. That is what we want when we lift off. With a flaps stall of 50, we have a Vref of 65 KIAS on approach. These numbers should keep us safe even on a gusty day.
A takeoff at 69 KIAS with 8 degrees trim gave a nice transition to cimb at 88.9 KIAS and 818 FPM on full throttle (2584 RPM).
Cruise Test Results:
Altitude RPM___KTAS__KIAS__GPH__MPG
4500__2500____127___119.1__10.13__12.54
4500__2400____121___113.5__8.94___13.53
6500__2500____126__114.4___9.23___13.65
6500__2400____120__109.0___8.25___14.54
8500__2500____125__109.9___8.97___13.94
8500__2400____117__103.0___7.99___14.64
The results are a little surprising. As you increase altitude, the mileage gets better but the speed gets lower. usually the speed gets better too with altitude. The difference is not great, but 4500 ft is best for speed and 8500 ft is best for economy, depending on winds. Incidently, you should note we offloaded, or left out 20% of our fuel to make room for luggage. We are carrying four full-size adults with enough luggage to stay some place for a week - 40 lbs per couple. Yet I forgot to pause the program after completing the second cut at 6500 feet cruising so it quietly fle on north from Huntsville while I practiced 80 minutes and too the dog out and did a few other things. When I came back it was near Terra Haute, Indiana, still chugging faithfully on with 3.9 hours of fuel remaining. So it's total endurance would be 5.7 hours. That's a lot more than mine. It could go as far as 700 nm on one 80% tank. That's a lot of travelling capability. It would probably beat any airline connection between non-major cities.
Getting these cruise figures took some patience. I had to re-do the flights at 6500 nm because I did not have enough patience the first time. The problem is that you cannot just dial in a power setting with a fixed-pitch prop and forget it. After climbing to the level desired for cruise, you leave the power high for a few minutes while the speed gets close to what you expect. Then to start diddling with the throttle to get the RPM you want. But this takes a while because it continually changes as the speed changes. The case of 2400 RPM at 6500 ft is one I know is good because it sat with that for over 90 minutes reaching a very steady state.
Descents are easy but don't do a spin. It will spin but it picks up a lot of speed. I saw vertical speeds of 10,000 fpm. That would do a number on your ears. Go to 4.65 gph or about half the cruise fuel flow and set -500 fpm on the autopilot. It will take a while - 12 mintues from 8500 ft to 2500 ft. But it will be a nice ride at about 119 KTAS.
You'll need to slow to 80 knots for flaps before an approach so you don't want to be faster than that when you start downhill on final. Reduce the power to 1500 RPM while holding altitude and doing some level turns. 80 KIAS will happen in good time. I had two good landings, one at 53.1 KIAS and -191 FPM and one at 55.5 KIAS and -73 FPM. Of course all this flying was in calm air on a "standard day." one thing you will not after flying the equivalent Cessna 172 SP is a stronger ground effect. The wings get closer to the ground on each landing.
Either the Cessna 172 SP or the Piper 180 (or the modern version known as the Archer) would make fine personal aircraft. There are pluses and minuses for each one in many practical aspects. Getting in and out is easier and drier in a rain storm in the Cessna. There are doors on each side leading to the front seats. Rain won't get in to mess up the seats of instruments. The Piper has one door for people to use on the right side. You step onto the wing and then enter to get to each seat. The pilot must enter before the right front passenger and then reach across to secure the door. on the Cessna the pilot can be the last to enter which is best. There is a door on the left rear to put bags into the baggage area. In the Cessna, everyone has a great view of the ground. On the Piper everyone has a great view of the sky which is good for watching out for other traffic. But only the front row people have a good view of the ground over the front edge of the wing. (On this model there is an unobstructed view in any direction because the default aircraft was not made with a virtual cockpit, needed for realistic views out the windows. However, shift+E will open/close the right side door.)
Tom Goodrick
Re: Flying Singles
« Reply #5 on: Mar 18th, 2007, 11:02pm »
COMPARISON OF SKYLANES
("T" STANDS FOR TURBOCHARGED) Based on data from 1985 FLYING ANNUAL
*Enhanced data
CONDITION____C182___CT182___C182RG___CT182RG
MAX T.O. WT.__3100___3100_____3100______3100 LBS
EMPTY WT____1810___1829_____1861______1901 LBS
USEFUL LD*___1300___1283_____1251______1211 LBS
CLEAN STALL___54_____54_______54________54 KIAS
FLAPS STALL___49_____49_______50________50 KIAS
LOW CRUISE__142_____142_____156________156 KTAS
HI CRUISE______X_____158_______X________173 KTAS
FUEL CAP_____528____528______528_______528 LBS
75% FUEL FLO__76_____87_______79________85 LB/HR
4 HR FUEL*___304____348______316________340 LBS
4 HR PAYLD*__996____935______935________871 LBS
ENGINES
C182________ CONT O-470-U 230 HP
CT182_______ LYC O-540-L3C5D 235 HP
C182RG______LYC 0-540-J3C5D 235 HP
CT182RG_____LYC O-540-L3C5D 235 HP
It should be noted that any cruise is conducted at 75% power as the normal high continuous power level. This means that the cruise speed of the turbocharged versions is the same as that of the normally-aspirated versions at the low level fo 7500 to 8,000 ft. 75% of 230-235 hp is the same regardless of altitude. The true airspeed will be better at high altitude but is about the same up to 6,000 ft. A comparison of speeds at altitude between the 182RG and the T182RG are shown below. All are at 75% power except for the first line which is at 100% power. Above 6,000 ft the RG was at max throttle which was slightly less than 75%.
___________________182RG____________T182RG
___________________KIAS__KTAS______KIAS__KTAS
500ft, 100%__________174___174________174___174
500ft 75%____________155___155________155___155
2000ft_______________153___156________151___155
4000ft_______________152___160________149___157
6000ft_______________149___162________147___160
8000ft_______________140___157________145___163
10000ft______________131___152________142___165
12000ft______________122___146________140___167
14000ft_______________________________138___171
16000ft_______________________________137___175 75% power set
18000ft_______________________________135___177 75% power is max
20000ft_______________________________126___172 67% power is max
DESCRIPTION: The Skylane is a high-wing, four-seat aircraft known for moderate speed and payload that is easy to fly. There is a door on either side next to the front seats. A small rear door permits direct access to the baggage area behind the rear seats. All models have a constant speed prop giving the pilot an extra lever to work with and slightly different workload when setting and monitoring power. The models with turbocharging and with retracting gear further complicate the pilot's work load.
TURBOCHARGING: The turbocharging in the T182RG is not excessively powerful, but, it is adequate. The critical altitude is low - 9800 ft. This is the altitude to which the engine can maintain max manifold pressure. You can get 75% of full power up to 18,000 ft. Then by 20,000 ft all you can get is about 67% power. This causes the speed at that altitude to be less than what you might expect. If you are looking through a list of aircraft, trying to find the fastest aircraft of a certain type, the ones that are turbocharged stand out looking like real winners. But this is not really true. Having the ability to fly high and fast does not mean it is really practical to do so. Without pressurization of the cabin, all on board (even pets) must use oxygen from a bottle when above 12,000 ft. while climb speed can be up near 800 fpm on the average to cruising altitude, coming down people's (and pets') ears will be hurt if you come down faster than 500 fpm without cabin pressurization. Thus, while a low-altitude cruise speed can be realised shortly after takeoff, it takes time to climb to a high cruise altitude, during which a much lower speed is used. While a the indicated airspeed used at cruise can be maintained during most of the descent at 500 fpm, it can take longer than a half hour to get down to pattern altitude at the destination. This requires good planning and limits the time you can uitlize full true airspeed at the high cruise. One of these days I'll do a complete round trip in the plain 182RG and the T182RG to show the real gain, if any, of turbocharging. Also, when using a high-altitude cruise, you are at the mercy of much higher wind speeds. There is generally a net loss when doing east/west round trips due to high winds. Often the west leg of the trip will require a stop for fuel. The net result is that many people who own turbocharged aircraft find they pay more for engine upkeep but do not get as much use of the high-altitude cruise as they expected. Getting an aircraft with a pressurized cabin generally gives better utilization. Even west legs against the wind can be pleasant if you are kept above unpleasant weather. Examples of these are the Piper Mirage and Meridian singles and many twins - Cessna 340 and 414, Beech Duke and Piper Aerostar. Most turboprop jets and fanjets have cabin pressurization because they need very high altitudes for reasonable fuel consumption.
But this discussion of turbocharging ignores the conditions underwhich you absolutely must have it. Those conditions would be when you live near mountains so that many of you flights are across the mountains. Use of airports at high altitudes (above 3000 ft msl) also means you need turbocharging for those hot days that make such an airport seem like it is at 11,000 ft. Flatlanders tend to forget about these situations. I put the turbocharging in the model of the 182S after doing the assigned trip ("Learn to Fly the USA") between Palm Springs and San Diego where you have to climb over an 8,000 ft ridge on a warm day. The 182S could barely make it. With turbocharging, it is a cinch.
I am going to skip to some more interesting aircraft that fly higher and faster. If you want any particular aircraft written up in this way, add a comment.
« Last Edit: Aug 11th, 2007, 5:14pm by Tom Goodrick »
Chris_Ross
Re: Flying Singles
« Reply #6 on: Oct 5th, 2007, 5:06pm »
Yes please
the King Air Series including the KA300 if you have it
Chris
Tom Goodrick
Re: Flying Singles
« Reply #7 on: Oct 5th, 2007, 8:23pm »
I don't have the 300 but we all have the 350. According to a report I have on the development and early tesing of the 350, they are very similar. To make the 350, they stretched the cabi a total of 34 inches which allowed 2 more seats. They added two windows on each side. The wings were stretched a total of 3 feet and 2-foot winglets were added. The engines remained the same. [re: Aviation Week & Space Technology, Sept 30, 1991, Ed Phillips]
The King Air report will start a new section on TURBOPROPS. I'll include notes about the B200 and C90B.
Allen_Peterson
Re: Flying Singles
« Reply #8 on: Oct 12th, 2007, 7:44pm »
While testing the 172sp with the power panel - to see if the HP was correct - I noticed that the plane does not have a MP gauge. Now, I thought that I couldn't fly without it, but the plane seemed to be flying just fine. I decided it was a personal problem. But anyway, why no MP gauge?
I also noticed that the 182s has a MP gauge, so why does it have one and not the 172sp? Also, the green areas of the 182s MP and rpm gauges are quite narrow. Is one only supposed to fly the 182s within those ranges?
Have a good day.
Allen
Tom Goodrick
Re: Flying Singles
« Reply #9 on: Oct 12th, 2007, 9:12pm »
You might also have noticed that beta does not change at all for the 172.
The reason the 172 has no mp gauge is that it has a fixed-pitch prop. It also has no "prop" control. The throttle controls RPM but not directly. When the 172 is operated properly, the RPM follows the throttle pretty well. But if you dive it a little the engine will "zoom" a bit without you moving the throttle.
There are a large number of aircraft with fixed-pitch props. All trainers are like that - Cessna 140, 150, 152, 170, 175, Piper Tomohawk, Warrior, Cherokee 140 and 180 and Archer I, II and III. Beech Skipper, Beech Sport.
Now all the Light Sport Aircraft have fixed-pitch props.
Controllable pitch props are expensive to buy and to maintain. They must be over-hauled every 400 hours or so.
In the Green
I goofed. Sorry. On first read I thought you referred to the green areas on the airspeed indicator. But you were talking about the MP and the RPM indicators. The answer is 'yes'; fly them only in the green arcs. One key word is 'fly'. On the ground when taxiing, you'll be below the green arcs. But you are not applying power so it does not hurt anything. You cannot control RPM below 1400 anyway.
Those green areas on the MP and the RPM indicators are common to most non-turbocharged aircraft. When flying, the MP should be no less than 15 inches and not much above 23 inches or whatever you can get. As you climb, you run out of MP. The RPM is kept between 2100 and 2400 RPM when flying. You would never want to pull the engine back to idle. It would cool rapidly and become damaged. It could sputter and die and be very difficult to start again until after your successful crash landing. Other planes have different upper limits on the RPM. In many cases you can use full RPM of up to 2800 on takeoff for a limit of two minutes. But then the RPM has to be brought back to 2500 or 2400. In most Beech aircraft, you take off and climb at 2500 and cruise at 2400.
In all aircraft with controllable pitch props, you set 15 inches and 2100 RPM for a standard descent and then level near the airport and keep the power the same while level and during final descent. While level you will naturally slow to gear and flap speeds and may need a touch of power if low on final. You don't cut the thrittle until the wheels are nearly on the ground.
The Skylane can fly at all the green and white areas of the airspeed gauge. The white area shows where the flaps can be extended. Yellow is a warning area. If the air is calm, you can venture briefly in the yellow area when recovering from a stall or something like that. You are never safe in ared area. Parts of the aircraft will break off. I don't remember the airspeed indicator on the Skylane that well, haven't flown one in months. but I think the indicated speed would go from about 55 to 130 "in the green." Its optimum cruise speed can be as high as 144 at 8,000 ft.
I few the Skylane tonight and looked at that old-fashioned airspeed indicator for the first time in years. I have three Skylanes, each with a different panel. I usually fly the one with the PFD and MFD. that airspeed indicator is an example of how marketing people can takeover even such a staid and technically correct company as Cessna. That is a very bad instrument. It is a TAS indicator. The letters TAS can be read clearly just above the calibration arc below center. That is why the green arc is so wide. The green arc for a normal KIAS indicator for the Skylane would go from 50 knots to 128 knots, perhaps 130 knots. Only TAS goes beyond 130 knots. Below is table of values I found last night in cruise for the Skylane at 3130 lb:
SKYLANE CRUISE SPEEDS
(All at 2400 RPM and 75% power)
ALTITUDE____KTAS___KIAS___MAP____GPH____NMPG
___8000____142____127____21.56___12.71___11.2
___7000____141____128____21.53___12.66___11.1
___6000____140____128____21.71___12.68___11.0
___5000____139____129____21.87___12.67___11.0
This illustrates how stupid it is to use an airspeed indicator that shows true airspeed. The thing that will break an aircraft or some part of it like the flaps, is dynamic pressure. Every aerodynamic force and moment acting on the aircraft is proportional to dynamic pressure. Dynamic pressure is proportional to indicated airspeed squared, and to the constant standard density at sea level. That is why indicated airspeed is so very important to the pilot who wants to fly safely. While intheory, you could use true airspeed, you would have to take altitude into account and use a different safety speed at each altitude. With indicated airspeed, one speed - say for stall, or for lowering flaps or for lowering gear, or for bending wings - works for all altitudes.
« Last Edit: Oct 13th, 2007, 9:09pm by Tom Goodrick »
Allen_Peterson
Re: Flying Singles
« Reply #10 on: Oct 16th, 2007, 12:45am »
Thanks for the info. By the way, when adjusting the power and drag on the Cherokee 180 I did notice that the rpm was now too high. I changed the fixed_pitch_beta from 19 to 20.5 in the propeller section to get the rpms back to 2700.
Have a good day.
Allen
Flying Singles
« on: Mar 12th, 2007, 3:25pm »
Single engne aircraft are what everyone starts with when learning to fly. Not even a student enrolled in an aviation school for airline pilots starts with more than one engine. There is enough to learn about flying a single engine plane when you first start without worrying about the speed and complexities of multi-engine aircraft.
Singles are subdivided into additional subclasses: fixed gear or retractable gear, fixed prop or constant speed prop. They have a variety of seats from one to as many as eight. They have many different engines - piston, turboprop and fanjet. Here we will only discuss piston engines. Some singles are turbocharged for flight at high altitudes and some are also pressurized so people can breath normally in the cabin. If not pressurized, you cannot descend faster than 500 fpm for long periods of time. Passengers would breath oxygen from a bag but that would not protect their ears from the decompression of a rapid descent. We make note of whther or not an aircraft is pressurized because that makes a difference in how you fly them.
The only difference in flying retractable gear aircraft is remembering to get the gear up after lifting off and to get it down before landing. Some aircraft have so much gear drag they can barely fly with heavy loads until the gear are tucked up into the wing or belly. One method of avoiding gear-up landings is to use the gear as a decelerator when you reach a low altitude near the airport after descending from cruise altitude. Then leave the gear down for the rest of the flight. Some aircraft have warning buzzers that sound if the throttle is retarded significantly while the gear is up. You must slow the airplane down enough before lowering the gear so it will not be damaged. In most cases I have installed a BASP light on my models. This is a light that is red when you are too fast. You cannot lower the gear until you slow down enough so the GASP light turns green. (GASP stands for Gear Air Speed). Usually this happens at a speed higher than the speed for lowering the flaps. (Yes, some of my aircraft have a FASP light, too). But in some cases, the designers allow the first notch of flaps to come down at a higher speed than the gear speed so you can get help from the flaps in slowing to gear speed.
A fixed gear aircraft usually has enough drag to slow down for landing by just throttling back to 1500 rpm and holding level flight for a while. With any aircraft, cruise is performed at some altitude well above the pattern altitude (800 to 1000 ft above the runway elevation). To descend you reduce power to 50% and then descend at 500 fpm if not pressurized. At or just above pattern altitude, you level off but keep the same low power until the airplane slows enough to begin final approach. dring that time you maneuver to get lined up for the approach.
Normally flaps are used to enable a steep descent without increasing the speed. But some planes have no flaps. In these planes you must do a slip to control your glide slope. The slip is done by banking one way and holding rudder for the opposite direction - just enough rudder so you do not turn and you track straight along the direction to the runway. This will be demonstrated in the discussions of the J-3 Cub and the Aeronca Champ.
If the plane has a fixed pitch prop, your only power control is the throttle and power is measured by the tachometer showing rpm. Having a fuel flow gauge is handy because that too is an effective measure of power. You will note that the rpm changes without your moving the throttle if you descend or climb a bit. This is an effect of loading the prop. Aircraft are generally set up so full throttle will give adequate power for takeoff. But at high elevations you may have to lean the mixture before you can even keep the engine running and make a takeoff. You should look at the fuel flow gauge and lean enough to maximize the fuel flow which maximizes the power. If there is no fuel flow gauge, maximize rpm with the mixture during the takeoff run at high elevations. Normal cruise rpm in any airplane is 2400 rpm. Normal low-speed rpm for descent or before making a landing approach is 1500 rpm.
If an airplane has a constant speed prop, it means you should be able to set the rpm using the prop control independently of the throttle setting The throttle setting then changes the manifold pressure (in inches of mercury from 15 to 30.) Any power setting consists of both a throttle adjustment and a prop adustment. If in doubt, push all levers forward for takeoff and then set max throttle and 2500 rpm for climb, 24 inches and 2400 rpm for cruise and 15 inches and 2100 rpm for descent. In many cases I provide a power Gauge that uses the fuel flow as the basis for showing power in percent max. 75% is normally used for cruise and 50% for descent.
Aircraft that have turbocharged engines (such as the Mooney Bravo and Piper Mirage) will show much higher manifold pressures than the "normally aspirated" engines. This makes setting power very confusing. I have put Power gauges in these aircraft to make it easy. This is a new gauge also included in many real aircraft that have fuel management computers.
In pressurized aircraft, I include a cabin altimeter just like the real aircraft would have. this will show the cabin is at 8,000 ft when the aircraft is at cruise altitude. This is done mainly so you have a littl piloting challenge during the descent. The pressurization system for most small aircraft uses engine or turbine pressure (all are turbocharged) to "pump up" the cabin. If you cut to idle when making a descent, the cabin altitude will drop sharply causing injusry. If normally managed with moderate power reuctions over time, you can descend the aircraft at up to 2000 ft per minute with the cabin "descending" only at 500 ft per minute. The faster and higher a plane flies, the more work the pilot must do.
« Last Edit: Mar 12th, 2007, 4:12pm by Tom Goodrick »
Tom Goodrick
Re: Flying Singles
« Reply #1 on: Mar 12th, 2007, 3:26pm »
Notes on flying the Piper J-3 Cub:
The Piper J-3 Cub has been one of my favorites since I learned to fly it as a kid. It was not something that inspired enthusiasm for its speed or aerobatics. But it got me up into the air to look at the world from a different perspective. I loved doing spins in it.
When I first flew the FS9 version, I was extremely dissapointed. I could not even taxi it to the runway and take off without crashing. I had no such trouble with the real J-3. Some idiot at M$ had cranked up the sensitivity to torque and p factor so much that it would flip over while taxiing when you applied throttle. In the real one you do have to give it bursts of throttle to get it moving and to keep it moving, especially on grass which was all I had to taxi, land and take off from. These problems can be reduced if you change the "Realism" settings which really have little to do with reality. They produce moire arcade-quality thrills than realism.
Set General to 100%, P-factor to 65-70%, Torque to 50%, gyro to 80% and Crash Tolerance to 70%.
Then use the FD files for the Cub from my web site. These will help greatly for takeoff, cruise, landing and spinning. I used the specs from Jane's Fighting Aircraft of World War II. Believe it or not, the J-3 helped win the war. It was used by artillery spotters. There was an instance during the Battle of the Bulge when a US general got a ride in a Cub and spotted some German troops. Then he sent US troops to a good position to counter the coming attack. The Cub was able to land and take off from roads or small fields.
The Cub was designed back in the 1930's. It has always had a gross weight of 1220 lbs. The J-3 version has a 65 hp engine. Other versions had more powerful engines. The FAA recently ruled that 1220 lbs is the limiting gross weight for Sport Aircraft you can fly in the US with a special license. The J-3 has "tandem" seating, that is, two single seats, one ahead of the other. Only the front seat has direct access to the panel and easy access to trim, mixture and carb heat controls. When flown solo, the pilot must sit in back. When a passenger is carried, the pilot usually sirts in front for a direct view of the instruments. The passenger has his own control stick, throttle (on the left side), brake and rudder pedals. The entry door is split horizontally between a solid (fabric) lower half and a plexiglass upper half. Both swing out, the lower half hanging down and the window half folding up and locking against the wing. The window can be left open during flight. This makes the plane good for aerial photography. There is a small baggage area behind the rear seat. The J-3 has no electrical system except the magnetos used for ignition. To start it, the prop must be turned by hand - very carefully. Of course in FS we just use Ctrl-E.
Here's a table of weights and CG locations. I used my XML gauges to read the weight and the CG position which is given in percent of the mean chord back from the leading edge. Because the J-3 has a rectangular wing, the chord is constant across the span. 25% is considered a good normal position for stability.
Front_000__000__000__000__120__200__200__200
Back_170__200__230__200__200__200__219__200
Bags_000__000__000__050__050__050__050__069
Xcg_24.2__26.0_27.6__30.3__28.8_27.9_28.7__29.2
GWT_921__951_981__1001__1121_1201_1220_1220
(We used the last column for the tests.)
To make the takeoff, get lined up and then advance the throttle halfway. When you have a little speed give it full throttle. Soon after that apply a little forward pressure on the stick to raise the tail (carefully). At 60 mph the plane will gently lift off. Some nose-up trim is in order so it climbs without stick force. Don't expect to rocket skyward. The climb is leisurely, normally about 450 rpm. I saw 53.21 KIAS and 517 FPM on the Landing Speed gauge during the climb. The entire climb is done at full throttle.
I checked cruise at 3000 ft and 5000 ft. Later it dawned on me that the altitudes should be 3500 and 5500 ft which are VFR altitudes. I am used to flying IFR all the time, which is required for jets and high altitude aircraft. There is theoretical condition known as "steady state" which is assummed for cruise. But in reality this is seldom achieved. in FS it can be achieved in the clear weather condition on autopilot. But the J-3 has no autopilot so we have to make many small adjustments and have a lot of patience. When you reach cruising altitude, set cruise power and trim for level flight. This is a slow process where you repeatedly make small trim adjustments. When you have the plane flying level with no stick force for several minutes, you have it in steady cruise. I remember continuously nudging the stick in the real J-3. There was no such thing as steady state. For power, I left the engine at 2200 rpm. I saw 71 mph indicated and 62.2 KIAS on the landing gauge. At 5000 ft I set 2200 rpm again and saw 74 mph indicated and 63.3 KIAS. The Garmin showed a ground speed (equals true airspeed with no wind) of 68 knots. That's about the extent of the Cub's speed. Add a head wind and fly near a highway and cars will be beating you. (But you have a more enjoyable view.)
The Cub has a tail wheel so landings are a little delicate. This type of plane is called a "taildragger". After WWII, most planes were given tricycle gear to avoid accidents during taxiing. But taildraggers are still popular where landings must be made on grass. I have given up trying to land a Cub in a crosswind in FS. The slightest later motion at the wheels during touchdown will put a wing into the ground. This is unexpected in FS because most planes in FS can skid sideways with no resistance. You can land a tri-gear aircraft crabbed 40 degrees to the runway and slide out down the centerline very peacefully.
You really need to have rudder pedals for realistic operation of a Cub because there are no flaps and the standard method of adjusting the steepness of your approach is to slip. You never dive an aircraft because it picks up too much speed. On my test flight I ended up at 5,000 ft directly over the airport where I wanted to land. I did a slip to lose altitude quickly. To do this, I lowered the left wing to hold a bank of 45 to 55 degrees and enough right rudder to keep from turning. The power was 1600 rpm, the airspeed showed 55 mph, the landing gauge showed 47.96 KIAS and -2119 FPM. That got me to 2000 feet quickly.
Then I leveled off, made a turn to line up and began a normal descent on final at 1500 rpm, 55 mph with the landing gauge showing 46.3 KIAS and -318 FPM. I landed with the tail very low at 31.00 KIAS and -106 FPM.
Jane's gives the cruise speed as 75 mph true. The stall speed is 38 mph. Those would be 65 KTAS and 33 KIAS. My landing speed was just under stall speed. That is what you want when you land a plane with a tail wheel. Otherwise the plane will fly again when you lower the tail (and increase the angle of attack).
There are two landing techniques for any tail wheel aircraft: three point and wheel landing. But my landing points to a third method in between the other two. On a three point landing, you try to get the main wheels and the tail wheel to touch at the same time with the airplane in a full stall. On a wheel landing, you touch down on the main wheels only and hold the tail wheel up as long as possible, applying some brakes very carefully. This is the recommended procedure for a DC-3. But the three-point landing is recommended for the J-3 and similar light aircraft.
The Cub is a lot of fun to fly around any local area. It is not much fun on a long cross-country. I learned that as a passenger on a flight in the winter from Anoka, Minnesota, to Brainerd, Minnesota. The J-3 does not have much of a heating system, especially for feet.
For lots of fun do spins. At about 4,000 ft, reduce the power to 1500 rpm, set carb heat on, and pull the stick back slowly. As the wings start to stall, keep the stick centered and hold full right rudder. The left wing and the nose will drop steeply and the plane will start a spin rotation. To recover let go of the rudder and push the stick forward before pulling back slowly.
Sometimes in the Cub I use the VC panel for a wide-angle perspective on landing and during taxiing. Normally I fly with just the 2D panel.
Try loading variations using the table as a guide. See what effect the various loads have on handling, especially for landing.
All aircraft that have carburated engines rather than fuel-injected engines have carburator heat controls. The J-3 has one. Any time the temperature aloft is cooler than 50 degrees (which is most of the time), you should turn on carb heat when you reduce the rpm to 1500 or less, This protects against ice forming in the venturi of the carburator where the air is cooled below ambient temperature and moisture is squeezed out. But turn off carb heat after you increase the throttle so you'll have full power available. FS9 does not seem to simulate this condition but it is good to develop this habit. Early versions of FS did a better job of simulating carb icing which has ruined the day for many pilots. It was the cause of my own one and only forced landing in a real Cessna 150.
Have fun.
« Last Edit: Mar 12th, 2007, 4:19pm by Tom Goodrick »
Tom Goodrick
Re: Flying Singles
« Reply #2 on: Mar 12th, 2007, 5:40pm »
Here are some notes on flying the Aeronca Champ. My first introduction to the Champ was in 1951 when my dad was taking lessons in one. I used to spend hours in the summer sitting by the office at the airport watching him do touch and goes. When he wasn't in the pattern, there were Bonanzas, Navions and Cessna 120's, 170's and 195's as well as Piper Cubs to watch. The Champ has made many comebacks in the past 80 years. It started in the 1930's a primary trainer. Yes, it is also one of those fighting aircraft listed in Jane's "Fighting Aircraft of WWII" as the "L-4". In the late 1960's when there were many expensive aircraft for sale (more types than available today), the Champ made a come back to a limited extent as the cheapest manufactured aircraft in version sold without an electrical system. But at the same time more expensive versions were offered with electrical systems which were needed for admission to most airports. (In the early days - up to 1970, control towers used light guns to signal airplanes approaching without radios. Today they are simply not allowed in the airspace near larger airports. But, again today the Champ is making another come back as a Light Sport aircraft.
It is similar to the J-3. Two people sit in separate seats, one in front next to the panel and one behind. There is a small space for bags behind the rear seat. A single wide door on the right side allows entry to either seat. But there are differences from the Cub. A solo pilot in the Champ must sit in the front seat where in the Cub he sits in back. The Champ has a higher empty weight and about the same gross weight. This means the payload in the Champ is less than in the Cub.
Here's how the loading works out:
Front__170__200__230__170__170__230__200
Back__000__000__000__170__170__000__150
Bags__000__000__000__000__57___100__47
Xcg__17.8__16.8__15.8_21.9_24.9__22.0__23.1
GWT_993__1023__1053_1163_1220_1153_1220
(The last column was used for the flight data discussed below.)
Taxi slowly and turn gradually. Lift off at 60 KIAS. Like the Cub, the Champ does not really rotate, it just starts lifting you into the sky. Climb at 65 KIAS with full power. I saw 62 KIAS and 532 FPM in a sustained climb.
I tested cruise at 3500 ft and at 5500 ft. At 3500 ft, 2400 rpm gave me 80 mph or 68.5 KIAS using 3.33 gph. At 5500 ft using 2500 rpm, I saw 80 mph and 69.0 KIAS using 3.48 gph.
Like the Cub, the Champ has no flaps so you need rudder pedals to fly it properly making lsips for steep approaches. During a slip to lose a lot of altitude (5500 ft to 2000 ft) I saw 83.6 KIAS and -1505 fpm on the landing gauge.
My landing was short and smooth at 42.0 KIAS and -36 FPM with a slight slip used off and on until just before touchdown.
This is a lot of fun to fly. At first the Champ was much easier to land than the Cub. I used some of the landing parameters in the Champ to help make the Cub more manageable.
Tom Goodrick
Re: Flying Singles
« Reply #3 on: Mar 14th, 2007, 12:00am »
Notes on the Cessna 172 SP AKA "Skyhawk SP"
This aircraft is new and faster version than the venerable version I flew 30 years ago and which Joe Zuzil flies today. Our 172 had a 160 hp engine and did well to cruise at 100 KTAS. Cessna still makes a plain Skyhawk with the 160 hp engine. But the SP version has a 180 hp engine and goes a bit faster. According to www.cessna.com, it cruises at 124 KTAS at 75% power at 8500 ft. They also say at the same condition it will fly 518 nm in 4.26 hours. That is demonstrating a speed of 121.6 KTAS. So we can assume it will fly somewhere beteen 122 and 124 knots true airspeed. That's a significant improvement. From the default 172 in FS9, I made FD for the old model 172I that I used to fly and for which I still have the owner's manual, a 172R which is the new 160 hp version and the 172 SP. This discussion concentrates on the SP version.
We'll look at the loading, the takoff, climb, cruise and descent conditions, make a fast landing and a slow landing and do some funny stuff including a spiral that went way outside the bounds of proper fligth and a spin that went flat, both inverted and erect, but from which we recovered. We'll discuss a new type of airspeed - Calibrated airspeed or KCAS. That is what Cessna has always given their stall speeds in. It is technically correct and practically useless. I feel very strongly they should not be allowed to do that but no one has asked me for my opinion. It is confusing. The only thing you see on the panel is IAS. You don't have time to dig out a table and try to interpolate. If they can give a table that converts CAS to IAS, they can use it themselves and publish the stall speeds in IAS. The CAS values are determined for a nominal max gross loading in a test aircraft with both a regular pitot tube and a special long pitot tube that gets the sensor well out ahead of the airflow disturmance of the wing.
In comparing the simulator to real flying, I get a little concerned that we must take some of the "game" out of it and impose a level of seriousness. 50 people each month, on average, according to the NTSB web site(www.ntsb.gov), die in small airplane accidents. On the personal side, my instructor died in a flight accident shortly after I got my license. During my training I came in one day and he was a little jumpy. He showed me why as we climbed out. He had just had a student kill the engine when they were at the low altitude where you can't do anything but land more or less straight ahead. He had managed to do a 90 degree left turn and land on part of a golf course. The plane was still there. The plane and the people were all OK except the golf course owners were unhappy. We always flew over that course in the pattern taking off to the north. Also while I was taking lessons I made takeoffs in a 150 and in a 172 for several months flying over a black hole in the forest just north of the runway where five people had died in an overloaded 172 on a hot August day. So, yes, it is a fun game and I like to try things in FS no one would dare try in real flying. That is part of what a simulator is good for. But bear in mind that real flying is serious nd requires knowledge of the many different aspects of flying.
Here is a weight chart for the C172SP. There is a lot of variation in weights used. I try to use realistic weights that include me (225 lbs these days) and "average people" of various types. 170 lb is a figure often used for an average passenger. But that is averaged through men, women and children. The average weight of a general adult male is near 200 lbs. The average weight of a military pilot is 180 lbs. (They have to keep in shape.) Many women would like to think the average weight is 120 lbs and that is probably right if you consider only college coeds. But a more realistic figure is 150 lbs. When doing meaningful weight and balance (and not being an airplane salesman) it is worthwhile to err on the high side. Filling the C172 with four real people is difficult and may mean you have to leave most the luggage and some fuel at home. When I filled it with my family of four, my oldest boy was 6 so it was fairly easy to do the job. Now it would be impossible! I will show only combined loading for each row. I cut that in half for flying so it is balanced laterally.
Front:__340__340__200__200__400__400__300__400__400
Back:__240__240__000__000__000__200__300__086__360
Bags:__000__000__000__000__000__000__000__120__000
Fuel:__42.8__008__053__053__053__053__053__053__053
Xcg:__20.8__19.9__15.2_12.9__15.0_20.0__22.6_21.9__23.5
GWT:_2460_2254_2144_1873_2344_2544__2544_2550_2704
_____________________________________*_________Fatal in 160hp on hot day.
* used for flight data, except 200/000 used for utility catagory.
The web site gives stall speeds as 53 KCAS clean and 49 KCAS with full flaps. I think I remember setting up the flight model for these speeds in KIAS. There fore we can use thes speeds to calculate takeoff speed.s. Safe takeoff speed is 1.3 x 53 = 69 KIAS. Vref on final is 1.3 x 49 = 64 KIAS.
I do not know if the same calibration chart would apply to the SP version, but, here is the table for the old 172I.
Condition__IAS__40__50__60__70__80 (all in mph)
Flaps Up__CAS_55__58__65__72__82
Flaps Dn__CAS_48__54__63__72__82
Stall speeds were 57 CAS mph clean and 49 CAS mph with full flaps.
They translate to just unde 50 IAS and just above 40 IAS. All you can see in the cockpit when you're too low and too slow is the IAS with no time to look at a table.
So, on takeoff we'll be looking for 70 KIAS to get airborn. We set the trim at 11.5 degrees. The takeoff is uneventful at full throttle. For climb you can use 80 KIAS. A convenient item with most aircraft, including the C172, is that the airspeed for climb is the same as the airspeed for a normal descent. Use 80 for descent when slow and near the airport but not yet on final. We'll do a cruising descent that is a little faster when coming down after a cross country on a smooth day. On a bumpy day, use 80-90 KIAS from cruise to the pattern.
During our steady climb, the Landing gauge shows 82.7 KIAS and 866 FPM on manual control and then 81.6 and 719 FPM on autopilot with 700 FPM set as the vertical speed. Full throttle is used in climb. as far as I know. (There could be a requirement to use 2500 rpm for the 180 hp engine.) If climbing above 4,000 ft, you will have to lean the mixture for the best fuel flow.
Here's a table of cruise values:
Altitude_RPM___GPH__KTAS__KIAS__NMPG
4500___2500__10.23___116.6__109.3__11.40
4500___2400__9.36____111.4__104.5__11.90
6500___2617__11.03___122.8__111.8__11.13
6500___2400__8.72____109.4__99.5___12.55
8500___2650__10.81___123.8__109.2__11.45 <<<Cessna Spec
8500___2400__8.22____107.7__94.9___13.10
Note that it is very effective to reduce the RPM with the throttle to fly more efficiently. Some people advocte that you lean the mixture to the lean side of peak power (peak fuel flow). But that can heat up the engine causing premature wear. It seems best to run the engine at reduced RPM but always at peak power where it operates in a safe manner.
For descent from cruise, I used 104 KIAS, 2250 RPM and got -494 FPM passing through 7,000 ft. Through 5,000 ft it was 2304 RPM, 110 KIAS and -490 FPM. I set up on a long straigh final to a busy airport at 89.9 KIAS and -660 with no flaps. I dropped 12.7 degrres flaps and landed at 63.4 KIAS and -170 FPM after rolling for a while to slow down (long runway).
Next I made a normal approach using the ILS. With 12.7 deg flaps I saw 71.6 KIAS, -396 with 1633 RPM. With 25.3 deg flaps, I saw 67.4 KIAS and -302 FPM with 1853 rpm to stay on the glideslope. With 38 deg flaps, The approach was steep and slow needing plenty of power. i saw 60.3 KIAS and -313 FPM at 1906 RPM. The landing occurred at 51.2 KIAS and -149 FPM.
With a forward CG (single pilot and nothing else) I tried a spin. It was a good thing I climbed to 5500 ft before starting. I was not carefull starting the spin and screwed up. It was going around and around all right but in a spiral not a spin. The difference is that a spiral has circular flight paths of significant diameter. The spiral allows speed to get high making recovery a touchy proposition. I managed ok but saw 120.7 KIAS and -7043 fpm rather constant during the spiral.
Next I was more careful and slowed the aircraft to near zero speed ina climb as I started the spin. This caused a quick flip to an inverted flat spin and then a change to an erect flat spin that showed the condition 0 KIAS and -8215 FPM. I managed to recover while pulling only a little less than 2.5 g's.
The Skyhawk, like many small aircraft can be flown under two sets of rules. At gross weight, it is in the Normal Category where the max g allowance is 3.8 positive. But at 300 lbs less it is in the Utility category where it can pull up to 4.4 g's. It can do many mild aerobatic maneuvers including slow-acceleration spins.
It is a fine personal transport as long as you don't carry big loads, seldom more than one other person and can afford the liesurely pace of about 115 knots.
Tom Goodrick
Re: Flying Singles
« Reply #4 on: Mar 17th, 2007, 10:54pm »
NOTES ON THE PIPER CHEROKEE 180
You can get this aircraft from my web site as part of the AI_Aircraft.zip download. That zip includes the De Havilland Dash 8 and the MD-83 that came with FS9 but as traffic aircraft (called "AI" for Artificial Intelligence). I have modified the .air files so that you can fly them. You can take a panel from the C172 for the Piper 180. Just copy the entire panel folder. I gave all aircraft in that download a flight check today and updated the download to include the latest FD improvements.
The Piper 180 used to fit in between the Cessna 172 and the 182 in capability. It has been upgraded now as the Archer with 150 lbs more gross weight and a tapered wing though the performance did not change much. The current C172SP with its 180 hp engine competes well with the old Piper 180. Like the Cessna SP, the Piper 180 has a 180 hp engine and a fixed-pitch prop. The Piper has a lower empty weight so it carries about 100 lbs more in the cabin with full tanks. The tanks are lightly smaller. It has a rectangular wing, often called a "Hershey Bar Wing" because is wings are shaped somewhat like Hershey Bars. The change to the Archer replaced those wings with sleeker-looking tapered wings. But performance did not change much. Somewhere along the way it got lower stall speeds. That probably came from new flaps in the 1980's. It has a long history. The Cherokee line (140 and 180) came out in 1960. The change to the Archer was made in 1973. Other updates came along in the 1980's and 1990's as Piper went through various ownerships. It has been manufactured almost continuously since 1960 with those few modifications. Cessna cannot say the same. Its 172 and 182 lines were shut down for a decade starting in the 1980's.
Here's the loading chart:
Front:__400___400___200___400___400___400___400___400___400
Rear:__300___300___000___000___000___000___200___280___300
Bags:__000___000___000___000___120___120___120___040___80
Fuel:__050___008___008___008___008___050___050___050___040
Xcg:__18.1__17.1___8.8____9.3___15.1__16.4___20.4___19.1__21.0
GWT: 2379__2127__1627__1827__1947__2200__2400__2400__2400*
*Used in flight for data.
I checked an old FLYING ANNUAL magazine from 1971 for the performance specs.
Nuts! I had just reset stall speeds. But in 1971 FLYING was still giving their performance data in mph, not knots. So I assume that 57 is with flaps and means 49.6 or 50 knots indicated. I expect clean stall would be about 53 KIAS. I went back to work and made that happen. I had to increase the lift coefficient for clean stall and decrease the flap lift factor. Now these numbers work.
The clean stall of 53 KIAS means V2 is 69 KIAS. That is what we want when we lift off. With a flaps stall of 50, we have a Vref of 65 KIAS on approach. These numbers should keep us safe even on a gusty day.
A takeoff at 69 KIAS with 8 degrees trim gave a nice transition to cimb at 88.9 KIAS and 818 FPM on full throttle (2584 RPM).
Cruise Test Results:
Altitude RPM___KTAS__KIAS__GPH__MPG
4500__2500____127___119.1__10.13__12.54
4500__2400____121___113.5__8.94___13.53
6500__2500____126__114.4___9.23___13.65
6500__2400____120__109.0___8.25___14.54
8500__2500____125__109.9___8.97___13.94
8500__2400____117__103.0___7.99___14.64
The results are a little surprising. As you increase altitude, the mileage gets better but the speed gets lower. usually the speed gets better too with altitude. The difference is not great, but 4500 ft is best for speed and 8500 ft is best for economy, depending on winds. Incidently, you should note we offloaded, or left out 20% of our fuel to make room for luggage. We are carrying four full-size adults with enough luggage to stay some place for a week - 40 lbs per couple. Yet I forgot to pause the program after completing the second cut at 6500 feet cruising so it quietly fle on north from Huntsville while I practiced 80 minutes and too the dog out and did a few other things. When I came back it was near Terra Haute, Indiana, still chugging faithfully on with 3.9 hours of fuel remaining. So it's total endurance would be 5.7 hours. That's a lot more than mine. It could go as far as 700 nm on one 80% tank. That's a lot of travelling capability. It would probably beat any airline connection between non-major cities.
Getting these cruise figures took some patience. I had to re-do the flights at 6500 nm because I did not have enough patience the first time. The problem is that you cannot just dial in a power setting with a fixed-pitch prop and forget it. After climbing to the level desired for cruise, you leave the power high for a few minutes while the speed gets close to what you expect. Then to start diddling with the throttle to get the RPM you want. But this takes a while because it continually changes as the speed changes. The case of 2400 RPM at 6500 ft is one I know is good because it sat with that for over 90 minutes reaching a very steady state.
Descents are easy but don't do a spin. It will spin but it picks up a lot of speed. I saw vertical speeds of 10,000 fpm. That would do a number on your ears. Go to 4.65 gph or about half the cruise fuel flow and set -500 fpm on the autopilot. It will take a while - 12 mintues from 8500 ft to 2500 ft. But it will be a nice ride at about 119 KTAS.
You'll need to slow to 80 knots for flaps before an approach so you don't want to be faster than that when you start downhill on final. Reduce the power to 1500 RPM while holding altitude and doing some level turns. 80 KIAS will happen in good time. I had two good landings, one at 53.1 KIAS and -191 FPM and one at 55.5 KIAS and -73 FPM. Of course all this flying was in calm air on a "standard day." one thing you will not after flying the equivalent Cessna 172 SP is a stronger ground effect. The wings get closer to the ground on each landing.
Either the Cessna 172 SP or the Piper 180 (or the modern version known as the Archer) would make fine personal aircraft. There are pluses and minuses for each one in many practical aspects. Getting in and out is easier and drier in a rain storm in the Cessna. There are doors on each side leading to the front seats. Rain won't get in to mess up the seats of instruments. The Piper has one door for people to use on the right side. You step onto the wing and then enter to get to each seat. The pilot must enter before the right front passenger and then reach across to secure the door. on the Cessna the pilot can be the last to enter which is best. There is a door on the left rear to put bags into the baggage area. In the Cessna, everyone has a great view of the ground. On the Piper everyone has a great view of the sky which is good for watching out for other traffic. But only the front row people have a good view of the ground over the front edge of the wing. (On this model there is an unobstructed view in any direction because the default aircraft was not made with a virtual cockpit, needed for realistic views out the windows. However, shift+E will open/close the right side door.)
Tom Goodrick
Re: Flying Singles
« Reply #5 on: Mar 18th, 2007, 11:02pm »
COMPARISON OF SKYLANES
("T" STANDS FOR TURBOCHARGED) Based on data from 1985 FLYING ANNUAL
*Enhanced data
CONDITION____C182___CT182___C182RG___CT182RG
MAX T.O. WT.__3100___3100_____3100______3100 LBS
EMPTY WT____1810___1829_____1861______1901 LBS
USEFUL LD*___1300___1283_____1251______1211 LBS
CLEAN STALL___54_____54_______54________54 KIAS
FLAPS STALL___49_____49_______50________50 KIAS
LOW CRUISE__142_____142_____156________156 KTAS
HI CRUISE______X_____158_______X________173 KTAS
FUEL CAP_____528____528______528_______528 LBS
75% FUEL FLO__76_____87_______79________85 LB/HR
4 HR FUEL*___304____348______316________340 LBS
4 HR PAYLD*__996____935______935________871 LBS
ENGINES
C182________ CONT O-470-U 230 HP
CT182_______ LYC O-540-L3C5D 235 HP
C182RG______LYC 0-540-J3C5D 235 HP
CT182RG_____LYC O-540-L3C5D 235 HP
It should be noted that any cruise is conducted at 75% power as the normal high continuous power level. This means that the cruise speed of the turbocharged versions is the same as that of the normally-aspirated versions at the low level fo 7500 to 8,000 ft. 75% of 230-235 hp is the same regardless of altitude. The true airspeed will be better at high altitude but is about the same up to 6,000 ft. A comparison of speeds at altitude between the 182RG and the T182RG are shown below. All are at 75% power except for the first line which is at 100% power. Above 6,000 ft the RG was at max throttle which was slightly less than 75%.
___________________182RG____________T182RG
___________________KIAS__KTAS______KIAS__KTAS
500ft, 100%__________174___174________174___174
500ft 75%____________155___155________155___155
2000ft_______________153___156________151___155
4000ft_______________152___160________149___157
6000ft_______________149___162________147___160
8000ft_______________140___157________145___163
10000ft______________131___152________142___165
12000ft______________122___146________140___167
14000ft_______________________________138___171
16000ft_______________________________137___175 75% power set
18000ft_______________________________135___177 75% power is max
20000ft_______________________________126___172 67% power is max
DESCRIPTION: The Skylane is a high-wing, four-seat aircraft known for moderate speed and payload that is easy to fly. There is a door on either side next to the front seats. A small rear door permits direct access to the baggage area behind the rear seats. All models have a constant speed prop giving the pilot an extra lever to work with and slightly different workload when setting and monitoring power. The models with turbocharging and with retracting gear further complicate the pilot's work load.
TURBOCHARGING: The turbocharging in the T182RG is not excessively powerful, but, it is adequate. The critical altitude is low - 9800 ft. This is the altitude to which the engine can maintain max manifold pressure. You can get 75% of full power up to 18,000 ft. Then by 20,000 ft all you can get is about 67% power. This causes the speed at that altitude to be less than what you might expect. If you are looking through a list of aircraft, trying to find the fastest aircraft of a certain type, the ones that are turbocharged stand out looking like real winners. But this is not really true. Having the ability to fly high and fast does not mean it is really practical to do so. Without pressurization of the cabin, all on board (even pets) must use oxygen from a bottle when above 12,000 ft. while climb speed can be up near 800 fpm on the average to cruising altitude, coming down people's (and pets') ears will be hurt if you come down faster than 500 fpm without cabin pressurization. Thus, while a low-altitude cruise speed can be realised shortly after takeoff, it takes time to climb to a high cruise altitude, during which a much lower speed is used. While a the indicated airspeed used at cruise can be maintained during most of the descent at 500 fpm, it can take longer than a half hour to get down to pattern altitude at the destination. This requires good planning and limits the time you can uitlize full true airspeed at the high cruise. One of these days I'll do a complete round trip in the plain 182RG and the T182RG to show the real gain, if any, of turbocharging. Also, when using a high-altitude cruise, you are at the mercy of much higher wind speeds. There is generally a net loss when doing east/west round trips due to high winds. Often the west leg of the trip will require a stop for fuel. The net result is that many people who own turbocharged aircraft find they pay more for engine upkeep but do not get as much use of the high-altitude cruise as they expected. Getting an aircraft with a pressurized cabin generally gives better utilization. Even west legs against the wind can be pleasant if you are kept above unpleasant weather. Examples of these are the Piper Mirage and Meridian singles and many twins - Cessna 340 and 414, Beech Duke and Piper Aerostar. Most turboprop jets and fanjets have cabin pressurization because they need very high altitudes for reasonable fuel consumption.
But this discussion of turbocharging ignores the conditions underwhich you absolutely must have it. Those conditions would be when you live near mountains so that many of you flights are across the mountains. Use of airports at high altitudes (above 3000 ft msl) also means you need turbocharging for those hot days that make such an airport seem like it is at 11,000 ft. Flatlanders tend to forget about these situations. I put the turbocharging in the model of the 182S after doing the assigned trip ("Learn to Fly the USA") between Palm Springs and San Diego where you have to climb over an 8,000 ft ridge on a warm day. The 182S could barely make it. With turbocharging, it is a cinch.
I am going to skip to some more interesting aircraft that fly higher and faster. If you want any particular aircraft written up in this way, add a comment.
« Last Edit: Aug 11th, 2007, 5:14pm by Tom Goodrick »
Chris_Ross
Re: Flying Singles
« Reply #6 on: Oct 5th, 2007, 5:06pm »
Yes please
the King Air Series including the KA300 if you have it
Chris
Tom Goodrick
Re: Flying Singles
« Reply #7 on: Oct 5th, 2007, 8:23pm »
I don't have the 300 but we all have the 350. According to a report I have on the development and early tesing of the 350, they are very similar. To make the 350, they stretched the cabi a total of 34 inches which allowed 2 more seats. They added two windows on each side. The wings were stretched a total of 3 feet and 2-foot winglets were added. The engines remained the same. [re: Aviation Week & Space Technology, Sept 30, 1991, Ed Phillips]
The King Air report will start a new section on TURBOPROPS. I'll include notes about the B200 and C90B.
Allen_Peterson
Re: Flying Singles
« Reply #8 on: Oct 12th, 2007, 7:44pm »
While testing the 172sp with the power panel - to see if the HP was correct - I noticed that the plane does not have a MP gauge. Now, I thought that I couldn't fly without it, but the plane seemed to be flying just fine. I decided it was a personal problem. But anyway, why no MP gauge?
I also noticed that the 182s has a MP gauge, so why does it have one and not the 172sp? Also, the green areas of the 182s MP and rpm gauges are quite narrow. Is one only supposed to fly the 182s within those ranges?
Have a good day.
Allen
Tom Goodrick
Re: Flying Singles
« Reply #9 on: Oct 12th, 2007, 9:12pm »
You might also have noticed that beta does not change at all for the 172.
The reason the 172 has no mp gauge is that it has a fixed-pitch prop. It also has no "prop" control. The throttle controls RPM but not directly. When the 172 is operated properly, the RPM follows the throttle pretty well. But if you dive it a little the engine will "zoom" a bit without you moving the throttle.
There are a large number of aircraft with fixed-pitch props. All trainers are like that - Cessna 140, 150, 152, 170, 175, Piper Tomohawk, Warrior, Cherokee 140 and 180 and Archer I, II and III. Beech Skipper, Beech Sport.
Now all the Light Sport Aircraft have fixed-pitch props.
Controllable pitch props are expensive to buy and to maintain. They must be over-hauled every 400 hours or so.
In the Green
I goofed. Sorry. On first read I thought you referred to the green areas on the airspeed indicator. But you were talking about the MP and the RPM indicators. The answer is 'yes'; fly them only in the green arcs. One key word is 'fly'. On the ground when taxiing, you'll be below the green arcs. But you are not applying power so it does not hurt anything. You cannot control RPM below 1400 anyway.
Those green areas on the MP and the RPM indicators are common to most non-turbocharged aircraft. When flying, the MP should be no less than 15 inches and not much above 23 inches or whatever you can get. As you climb, you run out of MP. The RPM is kept between 2100 and 2400 RPM when flying. You would never want to pull the engine back to idle. It would cool rapidly and become damaged. It could sputter and die and be very difficult to start again until after your successful crash landing. Other planes have different upper limits on the RPM. In many cases you can use full RPM of up to 2800 on takeoff for a limit of two minutes. But then the RPM has to be brought back to 2500 or 2400. In most Beech aircraft, you take off and climb at 2500 and cruise at 2400.
In all aircraft with controllable pitch props, you set 15 inches and 2100 RPM for a standard descent and then level near the airport and keep the power the same while level and during final descent. While level you will naturally slow to gear and flap speeds and may need a touch of power if low on final. You don't cut the thrittle until the wheels are nearly on the ground.
The Skylane can fly at all the green and white areas of the airspeed gauge. The white area shows where the flaps can be extended. Yellow is a warning area. If the air is calm, you can venture briefly in the yellow area when recovering from a stall or something like that. You are never safe in ared area. Parts of the aircraft will break off. I don't remember the airspeed indicator on the Skylane that well, haven't flown one in months. but I think the indicated speed would go from about 55 to 130 "in the green." Its optimum cruise speed can be as high as 144 at 8,000 ft.
I few the Skylane tonight and looked at that old-fashioned airspeed indicator for the first time in years. I have three Skylanes, each with a different panel. I usually fly the one with the PFD and MFD. that airspeed indicator is an example of how marketing people can takeover even such a staid and technically correct company as Cessna. That is a very bad instrument. It is a TAS indicator. The letters TAS can be read clearly just above the calibration arc below center. That is why the green arc is so wide. The green arc for a normal KIAS indicator for the Skylane would go from 50 knots to 128 knots, perhaps 130 knots. Only TAS goes beyond 130 knots. Below is table of values I found last night in cruise for the Skylane at 3130 lb:
SKYLANE CRUISE SPEEDS
(All at 2400 RPM and 75% power)
ALTITUDE____KTAS___KIAS___MAP____GPH____NMPG
___8000____142____127____21.56___12.71___11.2
___7000____141____128____21.53___12.66___11.1
___6000____140____128____21.71___12.68___11.0
___5000____139____129____21.87___12.67___11.0
This illustrates how stupid it is to use an airspeed indicator that shows true airspeed. The thing that will break an aircraft or some part of it like the flaps, is dynamic pressure. Every aerodynamic force and moment acting on the aircraft is proportional to dynamic pressure. Dynamic pressure is proportional to indicated airspeed squared, and to the constant standard density at sea level. That is why indicated airspeed is so very important to the pilot who wants to fly safely. While intheory, you could use true airspeed, you would have to take altitude into account and use a different safety speed at each altitude. With indicated airspeed, one speed - say for stall, or for lowering flaps or for lowering gear, or for bending wings - works for all altitudes.
« Last Edit: Oct 13th, 2007, 9:09pm by Tom Goodrick »
Allen_Peterson
Re: Flying Singles
« Reply #10 on: Oct 16th, 2007, 12:45am »
Thanks for the info. By the way, when adjusting the power and drag on the Cherokee 180 I did notice that the rpm was now too high. I changed the fixed_pitch_beta from 19 to 20.5 in the propeller section to get the rpms back to 2700.
Have a good day.
Allen