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Post by Bill Von Sennet on Aug 22, 2008 22:10:42 GMT -5
Tom Goodrick Basic Performance Information « on: Mar 11th, 2007, 6:42pm »
I found there may be some people who want to see some basci performance information on several different FS aircraft. To start this off, I intend to go through the aircraft on my web site (that everyone can download for free) to show basic info about them. I am including only those aircraft that would be used in normal flight, carrying payloads between two places. This excludes the special aerobatic aircraft meant just for fooling around. The point is that some people new to FS are not aware of the basic performance many aircraft offer. I will also give references for each aircraft to published performance specs that I used to develope the FD files to assure realistic performance. Any comments or questions are welcome as we go along. Also, if you have an interest in an aircraft not discussed here, just bring it up. I'll take a look at the existing files and fly the model to compare it to published performance specs. We may end up giving you a new airplane - in terms of performance. The planes I am starting with are: Singles: Piper J-3 Cub, Aeronca Champ (Yes, these are cross-country aircraft!), Cessna 172SP, Piper Cherokee 180, Cessna 182, Mooney Bravo, Piper Comanche 250, Beech Bonanza V35B, Piper Mirage, Velocity XL-5 Twins: Cessna 340, Baron 58, Cessna 414, Beech Duke, Piper Aerostar 700, Aero Commander, 680E, Beech 18 Vopar. Turboprop: Piper Meridian, Beech 350, Beech 200, Avanti, MU-2-60 Jets: Beech Premier, Lear 31, Lear 45, Lear 60, Hawker 400, Hawker 800, Westwind II, Falcon 50, Jetstar III, Boeing 737, 777, 747. In each case the Flight Dynamics were developed by me so I can go into detail. You may have other forms of these (some are default with FS9).
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Post by Tom Goodrick on Aug 26, 2008 11:11:12 GMT -5
PIPER J-3 CUB
The J-3 is a two-place, tandem seat trainer from the 1930's. Today it has found new life as a "Light Sport Plane" or LSA for which a special pilot's license can be obtained in less time and money but with restrictions. With two people on board, the pilot sits in front and the passenger sits in the rear. Both have a great view on either side. It is often used for air-ground photography because the door (on the right) has two parts, half folding up and locking under the wing and half folding down, can be left open in flight. When flown solo, the pilot must sit in the back. The FS model with my FD is very accurate, including the weight and balance. My magazines for the Cub have become lost so I had to make a flight to get performance data. But I had used those magazines to set the FD files originally so I know they are accurate. I also put in some time as a young CAP cadet flying the J-3.
To get performance figures I loaded it to the hilt with a 220 lb man in the front seat and a 230 lb man in the back seat with 19 lbs worth of camera gear in the aft baggage area. This put the weight at 1220 lbs which is max gross and the CG at 26.89%.
Cruise speed was 74 mph indicated at 2200 rpm and 1900 ft. This might be 75 or 76 mph true. With no autopilot, it takes a bit of work to get the J-3 steady in cruise.
Stall speed was 34 KIAS (using the landing Gauge) or 39 mph on the dial. Stall is rather abrupt. On the first landing I stalled it at about 4 feet above the runway and it crashed.
The second landing was good at 38.97 KIAS and -263 FPM.
Then the front person got out and I soloed it from the back seat with just the 19 lbs of camera gear remaining. The CG was at 29.35%.
It did a nice spin.
Cruise was 67.53 KIAS (78 mph).
The landing was good at 35.37 KIAS and -208 FPM. Both landings had an initaial bounce followed by a nice settling contact near stall. The landing gauge gets the first touch just before the bounce.
It is a fun plane to fly for a change of pace. But you don't want to fly this in any crosswind. It will be hard to keep it from ground looping.
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Post by Tom Goodrick on Aug 26, 2008 11:26:14 GMT -5
AERONCA CHAMP 7AC AND 7EC
I have two Champs. The 7AC has a limited electrical system - just a starter, battery and alternator with basic lighting. The 7EC has gyros and nav radios.
The Champ is a fabric covered two seater with tandom seats like the J-3. For some reason the Champ is much easier to land even though I have tried to make the J-3 as easy to land as the Champ. The Champ is another 1930's trainer. It is also accepted now as an LSA aircraft.
For this flight I loaded it with 200 lb men front and rear and no baggage. The weight was 1215 lb (max gross) and the CG was at 22.11%.
Cruise was 82 mph at 2400 rpm.
Stall was 36 mph. There is nothing other than a clean stall because the aircraft has no flaps. (The same is true for the J-3 Cub). To make a steep final approach, you must learn to slip the aircraft (stick left and foot right). (The Champ and the Cub do have only a stick for control.)
My first landing was good at 39.98 KIAS and -21 FPM.
You solo the Champ from the front seat. With just one 200 lb pilot, the CG was at 17.87%. This is an improvement allowing nice wheel landings if you like them.
Cruise was 85 mph at 2500 rpm.
Landing was at 34.35 KIAS and -30 FPM.
This is even more fun than the J-3 Cub.
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budsbud
Member
Cross winds of life
Posts: 211
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Post by budsbud on Oct 7, 2009 19:34:30 GMT -5
I am niot sure just where this should go but here it is. Several of my planes have the Bendix-King Radio Stack with the Autopilot included. All of them, when the plane loads, show an altitude hold of 1600 feet and the vertical speed as -2000 feet. If I punch up the AP I find I am plowing the west forty very quickly. Is there any way to set up these parameters prior to TO Please advise.
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Post by flaminghotsauce on Oct 7, 2009 20:52:24 GMT -5
Bud, can you call up the regular radio panel and preset it?
I did a flight today trying to nail down a number to use as fuel per hour in the 172. We always figured 9 gph in real life. I came up with 8.5 gph for this flight.
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Post by Tom Goodrick on Oct 7, 2009 22:24:31 GMT -5
Bud, I guess you are speaking of the one that comes with the radio stack when you do shift+2 to punch up the radio stack. There are others that I build into the panels. In either case you can set the numbers properly before takeoff, leave the autopilot OFF to make the takeoff and then turn it on after takeoff. If using the one in the radio stack, you can make the stack appera and disappear with shift+2 and then you can shove it around on the screen so it is in an unobstructing place. I usually put it up near the top of the screen so the rest of the stack disappears above the screen. It obstructs less of the panel.
Flaming, what is the point of your comment? Are you saying the 172 is performing inaccurately? I would ask how accurate your general knowledge is. Is it accurate to the nearest 10th of a gph? I'd say 8.5 is close to 9. How accurately have you matched the altitude? The throttle and mixture? Which engine are you flying - 150, 160 or 180? What are you trying to say?
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Post by Bill Von Sennet on Oct 7, 2009 22:35:32 GMT -5
Bud in the auto pilot section of the aircraft.cfg file there is a line:
default_vertical_speed=500 The 500 can be changed.
When I fly, I always check to make sure the auto-pilot is off and set the climb rate and initial cruise altitude before I take off. I then engage the autopilot as I pass through 500 ft above ground level.
You may have saved a flight with the -2000 descent rate still on the auto-pilot. That would carry over to subsequent flights. If the saved flight is the default flight, the setting may carry over to other aircraft when you change them.
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Post by Tom Goodrick on Oct 7, 2009 22:41:50 GMT -5
You'll find more info on using the autopilot in my article in the section "FS Piloting Procedures" and the thread "Understanding the Autopilot".
But, in short, you should always set the parameters in the autopilot for your flight before takeoff and then simply turn it ON when you begin your climb to altitude. Many bad things happen if you turn it on while on the ground.
With the autopilot ON in any mode, you are still responsible for setting gear and flaps. You are also responsible for setting the throttle unless you are using Speed mode which I strongly caution against unless you are sure your speed setting is well within the performance envelop for the aircraft. I only use it with certain jets that change speed too much when fuel burns off.
I operate the autopilot in the ALT mode (climbing to, decsending to, or holding an altitude) and in either HDG mode or NAV mode for steering. Boxes can be clicked in to set these modes. in HDG mode, you change the Heading number to get the aircraft to fly a heading. In NAV mode it will follow a flight plan if you have loaded one.
As Bill mentioned above, there is a way to set a climb rate so that when you select a higher altitude it will always use that climb rate. But anytime you selct the ALT mode and enter an altitude, you can set the vertical speed. This is very important if you are climbing high and the airspeed is dropping off. Reducing the climb rate gives you more airspeed. Also, I have found that whether climbing or descending, the preselected rate does not always activate so it is a good idea to make sure the rate set is what you want.
Any number in a window on the autopilot head can be changed by placing the mouse pointer on the left edge to increas or on the right edge to decrease and then tapping the left mouse button.
NAV mode can only be used if you have set up a flight plan. If you do that, and set the NAV/GPS mode at GPS, then the autopilot will fly a proper course in a wind to each of the waypoints in the flight plan. When reaching the destination, be sure to set NAV/GPS back to NAV to enable the proper ILS display.
The Z key turns the autopilot ON and OFF.
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Post by flaminghotsauce on Oct 8, 2009 4:20:53 GMT -5
Tom, I'm going to do a little flight schooling of my kids for home school purposes. All I was saying is that I took a flight to try to nail down a number to be used for planning purposes. I'm still going to use 9gph, that's pretty close.
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Post by Tom Goodrick on Oct 8, 2009 8:58:03 GMT -5
All I was saying is that there are many factors that affect gph and it sounds like you think there should be only one constant number - an integer. If you are flying one of my Cessna 172's, the gph should be fairly accurate - within .25 gph. FS gives you the chance to see how that varies with power setting (throttle and mixture), cruise altitude, engine and payload. Of course when you use any figure to estimate fuel needed for a trip, it should be on the high side and it is hard to tell how accurate you can be because of things like taxi time, etc.
My Cessna 172 handbook for a 1968 150 hp model shows from 6.3 to 9.7 gph at 2500 ft and from 6.0 to 9.0 gph at 5000 ft. But those top gigures are at 2700 RPM which no sane person uses when cruising. If I remember right, my 172 package on the web site includes 150, 160 and 180 hp engines. The 150 hp engine behaves very close to my handbook figues. I resurrected the 150 hp version when Joe bought one.
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Post by flaminghotsauce on Oct 8, 2009 14:26:01 GMT -5
I'm using the default FSX 172SP. I'm only interested in a round number at this point. I'm gearing up to teach them how to flight plan, and execute. It's not a critical number. I'm more interested in seeing the kids do the math. I'm not real concerned if it's off by 1/2gph. I just wasn't sure what it was burning. I don't usually do full length trips down to the reserves, so I haven't bothered to clock it.
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Post by flaminghotsauce on Oct 11, 2009 17:36:40 GMT -5
I did another flight today, longer, for the same purpose. But the weather was low, and I was in a hurry. I used the "no sane person" method! I started out at 3,000' but the clouds closed in and I dropped down to 2,000'. I mostly kept it firewalled. I was able to attain 116 kias. After about 1 3/4 hours, I'd burned 30 gallons, around 11 gph. Insane method. I figure this would be the highest gph the Cessna 172 would be able to do, low altitude, full throttle.
I have tomorrow off as well, I may do a similar length flight in sane mode to compare. Sane= more normal cruising altitude and power settings.
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Post by Tom Goodrick on Oct 11, 2009 21:52:34 GMT -5
The 172SP has a 180 hp engine.
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budsbud
Member
Cross winds of life
Posts: 211
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Post by budsbud on Feb 18, 2011 10:45:52 GMT -5
When in need of sound advice ask the experts. Problem: I recently downloaded a DeHavillan DCH-3 Otter from Avsim. It flys pretty well BUT changing the prop pitch control has no effect on the engine performace. It seem that the prop control is not connected to the FS. In viewing Toms Power Panel the prop control changes the beta angle as it should, I think. If moving the prop control has the desired effect in the Power Panel, which indicates the control is working through the FS, then what could be disconnecting It from the planes operation? Any suggestions. Thanks Bud BGAN063
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Post by louross on Feb 18, 2011 12:02:14 GMT -5
The Beaver has a PT6a turbo-prop engine (Pratt and Whitney). Typically, but I have no guarantee of this part, is that it consists of (1) contant speed, (2) full feathering, (2) reversible, (3) three bladed (4) Hartzell prop. There could have been some modifications later on some a/c and possibly some a/c don't reverse. I don't know.
Here are some things you should, or could know, if you are using the a/c in FS. This is a very unique engine. The engine is quite short- because it is a reversible flow engine. That is, it is not a tube like other jet engines. Air goes into the engine from the bottom. You can see the intake. As the air moves rearward, it goes thru compressors, and then it is ducted up and forward thru more compressors and then to the burner can. So at this point the thrust produced by the engine continues forwrd to the power turbine, gear box, etc, etc. Then it is vented overboard from the front. You can see the exhaust tubes. Now, this is an important point: the prop unit is not connected in any way to the engine. Hence, it is called a "free turbine". The result is, the operation is unlike other turbo prop, or even any other type engine. Now unfortuntely, and it is unfortunate, FS does not model the behavior correctly; it is not even set up correctly by the default, and most all FS pilots fly it incorrectly and use invented ideas as to why. Increasing prop RPM from idle takes a little longer, prop RPM reduction takes a little longer, than other engines- jet or piston, due to the free turbine. However if the engine is carrying power, response to RPM increase is virtually immediate. Because of the free turbine, the engines are started and shut down with the prop in the full feather position. You can practice engine failure procedures by feathering the prop with the engine still operating. However, when feathering, the engine needs to be at idle or the prop gear box will over torque. Condition levers. Are either in the cut-off position or the low-idle position. There is no reason what-so-ever to use high idle. In fact, never came across a pilot who knew why high idle was there in the first place.
Beta range. Uhhmmm. Okay, I don't know your personal definition of beta range, however, the PT6 operation does use "Beta Range" tecniques. Probaby unique to this engine. This is not modeled in FS. Sorry. Now, due to all the above, and probably more, you are not going to get proper ops behavior in FS- neither the engine itself, nor the a/c. The two a/c I flew that had the PT6, were the DHC6 Twin Otter with one company, and the Beech 99 with another. These are not pressurized, therefore, the FAR's require(d) a max altitude of 10,000 msl. (Has that FAR been changed?) You could go over 10 thou for max 30 minutes, up to a max of, uhhh, oh well. But these planes burned 600 lbs/hr. That's it. Cruise at 10,000 or 3000. Climb/descend any way you wanted. The plane burned 600 lbs/hr. No auto pilots. Why? auto pilots weigh. That weight means less payload = less money for the company. We were usually right at MGW on take-off (occassional rumors floated around that some thought, at times, maybe, a titch over). And max flights of hour and a quarter ( except when holding; I've held for an hour!). I can fly it easier than using an auto pilot.
I am at your command for any additional info I can provide. I'll answer questions or offer clarificaions and confirmations. If someone wishes to tell me I'm wrong or otherwise argue these points, preface your point with number of actual hours in the a/c and whether right or left seat. After some time (I'm a slow learner) I have learned that there are things that some FS'ers and some developers don't like to hear. (i'll grab my hat and coat and leave now) lr.
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