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Post by Tom Goodrick on Oct 2, 2008 16:14:09 GMT -5
Here's a list of the airports that serve as waypoints. The list shows the distance from the previous airport.
Granby GNB (8203 msl) (start) Glenwood Springs GWS (5916) 74 nm Garfield Cnty and Rifle RIL (5544) 19 nm Grand Junction (4858) GJT 44 nm Canyon Lands (4553) CNY 61 nm Bullfrog Basin U07 (4167) 86 nm Page PGA (4313) 57 nm Grand Canyon (6606) GCN 68 Grand Canyon West (4775) 1G4 81 nm Echo Bay (1535) 0L9 37 nm Boulder City (2201) 61B 29 nm Bullhead City (695) IFP 50 nm Lake Havasu City (781) HII 37 (London Bridge) Yuma YUM (216) 116 San Luis (50) MM20 16 nm El Doctor (50 msl) MM0G 30 nm
I have started the route in a Baron 58P flying a few thousand ft above the surface to make photos along the route. There are parts in the beginning where the river is barley visible. It would be good to have the flight plan that shows straight lines between each of these airports.
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Post by Tom Goodrick on Oct 1, 2008 21:41:58 GMT -5
In the September Issue of AOPA PILOT, Patrick J Mathews published an illustrated article about flying down the Colorado River. I think this would make a very interesting Fall Fling as we have done before. It would not take too long, about two weeks I'd guess.
It starts at Granby, Colorado and ends at Yuma, Arizona (but we could consider a final leg into Mexico to the Sea of Cortez). It descends in elevation from 8,203 ft at Granby to 213 ft at Yuma. We could start it in mid to late October as winter comes into Colorado and end in the perpetual sunshine of Yuma - a nice change.
Mathews lists a series of airports suitable as fuel stops or overnight stops. I have added a couple near Hoover Dam. The idea would be to make a landing at each airport in the list. A few scenic photos along the way could be posted for the enjoyment of others. The Grand Canyon is right in the middle of this trip so there should be plenty of good scenery for those who hug the ground. Ant airplane would be suitable though you might want to practice flying some out of Granby where the air is a little thin.
I would prescreen and select a set of Real Weather files you can download for certain sets of legs. The point is to experience topical and local weather without making it an IMC experience and without messing up the scenery.
Right now I have a list of 13 airports. The article says the overall distance is 1450 miles. But I just made a flight plan from Granby to El Doctor (MM0G) and it only shows 797 nm with straight legs between all airports. There are 15 airports including San Luis which is needed for Mexican Customs. I'll work up an info sheet on all the airports. I envision this as being strictly eyeball navigation.
Do we want to keep track of fuel and flight time?
Please let me know what you think.
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Post by Tom Goodrick on Sept 23, 2008 19:51:15 GMT -5
The other day I was reviewing the old aircraft that are available for various uses today. One of the best aircraft in many respects is the Baron 58. It is reasonably small and light yet it has a lot of capability. It offers twin engine safety at night and in IFR conditions. This makes it very useful to businesses where it must be able to make trips in most of the weather encountered. Indeed it is used nightly to run banck checks, medical specimins, and various business papers around the US.
But a major shortcoming of the regular Baron 58 is that it must fly "in the soup" most of the time. Passengers don't like this which is why most business applications do not involve passengers. But if you bring in the pressurized version of the Baron that was made between 1979 and 1985, then you have a versatile passenger carrier. It will maintain an 8,000 ft cabin at 20,000 ft and can go up and down quickly enough to utilize the higher altitudes where you look down on the clouds, precip and turbulence, passing through them only briefly at the beginning and end of the flight.
So I used the 1985 FLYING ANNUAL to make a normal Baron 58 into a Baron 58P. The span is the same but the area is less. This increases both the wing loading and the aspect ratio making it faster and more efficient. Also, the gross weight was increased significantly from 5500 lbs to 6200 lbs and the useful load from 2057 lbs to 2214 lbs. Where the normal Baron 58 cruises at 203 knots at 5,000 ft, the P Baron cruises - supposedly - at 241 knots at 25,000 ft. A more practical cruise is 236 knots at 20,000 ft where the cabin is at a more comfortable level for all on board. Fuel flow goes up only slightly from 210 pph to 223 pph. (Cruise power is decreased by 2% and engine power goes from 300 hp to 325 hp per side.)
The landing speed goes up about 4 knots with the stall speed with flap.
The result of all this is a nice-looking aircraft (the same as the default aircraft) that goes faily fast and goes high when it has to jump over mountains or storm clouds.
I looked up some current examples of Baron 58P's that you can buy today. They ranged from a 1981 with 3300 hrs at $450,000 to a 1985 with 3078 hrs at $405,000. I changed the N number of the one I fly to N58PA which matches the 1981 model that is still flying a fair amount in the Southwest. You can change yours by simply typing in a new N number when you load the aircraft.
I can send you a new aircraft.cfg file that includes all the changes. You simply copy the present Baron 58 folder to a place outside of the FS9 folder, switch my aircraft.cfg file for the old one and copy the folder back into FS9 where it will reside nest to the Baron 58. You might want to change the panel a slight bit. I simply used the panel from my Beech Duke with a switch in the cabin altitude gauge and the GASP gauge for the different values of the Baron. having a cabin altitude gauge is handy in that it shows you what the pressurization does for you. There is also a pair of TIT gauges instead of the EGT gauges because the 58P is turbocharged.
Send me an email and I will return the aircraft.cfg file and the two special gauges.
By the way, you might wonder why I made the 58P when we already had the Duke which is also a pressurized twin. Then answer is the 58P uses less fuel. It has 325 hp engines compared to the 380 hp engines on the Duke. The weights are also different.
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Post by Tom Goodrick on Sept 23, 2008 10:24:03 GMT -5
My advice to any who want to get a Wii is still to checkout frequently the nearest Super walmart or Sam's Club. These sell groceries at good prices so you can always check the Wii situation when picking up some groceries. That's how we got ours and how my wife got the Wii Fit the other day. BTW that is more fun than I expected. It gives you a considerable variety things to do that provide either a little balance and agility work or some actual effort that will quickly work up a sweat - like running on a path around an island with mountains, rivers and other runners. For light effort I do the balance events although you can't beat the Yoga breathing exercise where you just stand still and take measured deep breaths.
The first balance exercise involves leaning left and right as needed to hit a soccer ball with your head. The team kicks balls at you and you must bend left or right at the waist to get your head in the way of the ball. You must dodge the occasional shoe or Panda bear head !? Slalom skiing is neat. You bend left and right to steer though gates and bend forward for speed. Ski jumping gives your thighs a little work as you bend you knees and keep a red dot in a blue dot by balance for speed and then straighten your knees quickly (but do not actually jump) to fly off the sky jump. There is a game where you ride down a river in a bubble bending left and right to move laterally and fore and aft to control speed. Touching the bank pops the bubble.
In all these activities, records are kept of who has done the best.
But I have one word of warning. If you are sensitive about your looks, among family and friends, you may be humiliated at least a little. At the start the board you stand on measures your weight, you tell the game your height and it computes your Body Mass Index or BMI. Then it gives you a few simple balance exercises to determine your level of body control, flexing your body to move a dot around the screen. Then it gives you an "age" and shows where your BMI ranks on a general chart. My age is 75 - 10 years older than actual. I am ranked near the top of the chart at the "Obese" end. My character, who does all the events, looks very fat. The game is unkind and unfare to us older folks. It was obviously developed by young people.
I just read the comments by customers to Woods'09 golf at Amazon. I will not bother getting Woods'09. I am happy with Woods'08 and can continue playing PGA events for subsequent years on that. I have just finished the '09 season and am halfway through the Fed Ex Playoffs for '09 (winning every game).
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MD 80
Sept 20, 2008 10:29:20 GMT -5
Post by Tom Goodrick on Sept 20, 2008 10:29:20 GMT -5
I don't know what the effect is but it's too late after the slats deploy with a stall close to the ground. The only solution is to lower the nose considerably and trade altitude for speed to recover.
I made a takeoff on the numbers for flaps but with flaps up in the MD-83 and it worked fine. But I had a nice 10,000 ft runway. If the runway was short, there would have been a problem.
I must also say that my calculations and the behavior of my MD-83 may be sufficiently inaccurate to invalidate the solution I postulated (ie- using the proper numbers for takeoff). The factor of 1.3 over stall speed expecting takeoff flaps may not get you to a safe airspeed with no flaps. Then there are such variables as wind, payload and CG.
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MD 80
Sept 17, 2008 22:50:40 GMT -5
Post by Tom Goodrick on Sept 17, 2008 22:50:40 GMT -5
While it is conceivable that lack of flaps could cause a crash, it is unlikely if proper procedures were followed. The flaps on a large jet airliner are very significant during takeoff and landing. I dug out the numbers on my version of the FD for the MD-83. They may not be highly accurate but they are reasonable.
Takeoff and stall performance both depend on the lift coefficent. With all the flaps retracted, and if loaded to max gross weight, the stall speed is 153 KIAS. With full flaps as used on landing, the stall speed is 110 KIAS. With half flaps as might be used on takeoff, the stall speed is 127 KIAS. Let's say they were expecting half flaps so 127 KIAS would be the stall speed. If they tried to lift off with a fast rotation at 140-150 KIAS, yes indeed, they would remain airborn only for a short time and then would crash. But if they followed proper procedure and lifted off at V2 - takeoff safety speed which is 1.3 x stall, they would lift off at 165 KIAS and be safe even if the flaps had not deployed.
One would expect that 140-150 kIAS would not even get them off the ground. But there is a dynamic effect on the wing lift of a rapid rotation that can keep the air attached longer than in steady flight so their may be enough lift to get airborn but not enough to sustain flight.
Of course one can see all kinds of scenarios where these numbers could get closer and the lack of flaps could cause a crash. I heard there was speculation the flap position indicator was malfunctioning.
In the US it takes at least a year for the NTSB to compile a report on a crash like this. There are always many factors to consider. The cause is seldom obvious. But if all the flaps are found retracted in the crashed wings, that is a clear indication flaps were a factor. But it may still have required the pilots to follow an improper procedure.
This FD can be downloaded from my web site and used on the AI MD-83 that comes with FS9.
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Post by Tom Goodrick on Sept 17, 2008 15:36:29 GMT -5
A new chapter is being written in my Cat Story. Our three male cats are now full grown and we are searching for a vet that offers neutering at a low cost - maybe a package deal. Our house may not hold up for long with them carrying on in their "extra" bedroom. They really do bounce off the walls.
But the new chapter involves the five other cats that have joind us temproarily. My wife noticed that our cats' mother was getting amorous again with one of their fathers. Sure, enough a few weeks later she was obviously pregnant and then a bit later it was obvious that she had left her load someplace. We assumed she had them in the same place she kept ours until they grew old enough to escape and get into trouble with the neighbors' dogs. We marked on the calendar when we though the birth occurred and kept out eyes open for possible trouble. Then with the kittens about at three weeks, the mother started hanging around our house a lot. one day when our cats were exercising in the house, we let the momma cat see her black kitten with white paws that looked just like his father. She came into the mud room and they sniffed each other. He was very happy to see her.
The next day my wife heard a rustling sound in a box in our garage. It was full of five kittens and a nursing momma. My wife has continued to feed several neighborhood strays in the back yard and a couple, including Momma and a nice old big gray Tom that we call "Mr Gray" had been invited into the garage where they got special food. Mr Gray took to sleeping on or in our car.
Well, Momma's milk was pretty good but we noticed the kittens were getting big and were probably growing teeth which makes it tough for Momma to nurse them. So we quickly rigged a playpen from some boards my son had laying around. We put a litter box in it and some toys and put the kittens in there to play and eat. They get commercial cat's milk, baby food (chicken and turkey) and kitten chews. Our plan is to keep them a few more weeks and then give them to a store, vet or pet society for sale or giving to the public.
But it is not that simple. Because the Momma is not only a stray but is considered a "feral Cat" by some local people, we have been told that no pet society people will take the kittens. I have offered to pay for a Leukemia test on one kitten (which I am sure it will pass because our others did). We know one kindly vet who may help us.
We certainly do not want to add the five kittens to our existing troupe. There is one female who is all black like Momma. There are four male kittens who all look like the papa - black with white sox of varying sizes, some white on the face and little stub tails. They are just like our Charlie. Once grown we'd have a tough time telling them apart.
One strange thing is that their papa has not been seen since he walked away "arm in arm" with their momma. She came back pregnant and he dissappeared. Before he was a regular visitor at our back porch cat-feeding station.
The one thing we are certain of is that very soon, Momma will visit the vet and get "fixed" so this chain of events will end. She will not be happy about that trip and may have a tough life after that. We will let her stay, as well as Mr Gray (who seems to have been fixed) in our yard and garage where we do no longer have a problem with mice or rats.
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Post by Tom Goodrick on Sept 17, 2008 15:09:26 GMT -5
In the October issue of FLYING Magazine, Richard L Collins has published his last "On Top" column. I am sorry to see ON TOP come to an end because that has been the first article I have read in each FLYING mag for many decades.
I decided to see what the oldest magazine was I could find quickly in my den with an ON TOP article in it. It is the June, 1970 issue. Richard gave a fine discussion of wake vortices. This was just a few years after I got my aeronautical engineering degree and had studied wake problems to some extent. Richard was right on target, of course. Next to this magazine in the pile was the July 1971 issue where he talked again about some wake vortex problems and then about his brand new Piper Cherokee Six. That was about a year before I started taking flying lessons. There was a direct relation between Richard's writing and my interest in personal flying. I know he had owned a 182 before the Six, and then he bought a 172 after owning the Six for just a few years. Why? It seemed the Six fit his family. Then there was the Cardinal RG just after that. Next thing was the P210. He went from the Six to the P210 in one decade. Then he kept that for about 28 years. When he left that one in Georgia, it shook my confidence in older airplanes! (So many of the "good" airplanes are "older airplanes.")
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Post by Tom Goodrick on Sept 14, 2008 11:51:29 GMT -5
Here are the numbers for 25 jets. These are both the input values and some output from the spreadsheet using the equation shown above. The minimum thrust/weight ratio shows the most economical cruise condition and the best rate of climb airspeed. The thrust/weight at 250 KIAS gives another value at a higher speed (in most cases). If you have the spreadsheet, you can see the Thrust/weight required for any airspeed.
TABLE OF AERO PERFORMANCE PARAMETERS, JET AIRCRAFT
AIRCRAFT___CD0___W1/S___W2/S___AR___e___*min T/W___min T KIAS__T/W for 250 KIAS Astra SP IAI__.0200____42_____74____8.78__0.80___6.02%____180_________7.21% B737-400____.0303____65____132____7.90__0.75___8.07%____230_________8.21% B747-400____.0151____69____150____7.67__0.68___6.07%____300_________6.45% B777-300____.0220____77____143____9.69__0.60___6.94%____260_________6.95% Ces 510 Mst__.0136____25____41_____8.74__0.85___4.83%____145_________7.86% Ces 525 CitJ__.0176____26____40_____8.50__0.85___5.57%____135_________10.16% Ces 550_Cit__.0215____23____41_____8.28__0.60___7.42%____145_________12.36% Can_601____.0308____49____85_____8.39__0.90____7.21%____170_________9.37% CRJ-200____.0239____48____76_____9.00__0.75____6.72%____175__________8.36% Eclipse 500__.0195____20___32______8.00__0.8____6.23%_____125_________13.67% Emb RJ 135__.0171____44___76_____7.85__0.66____6.92%_____200_________7.64% Falcon 2000__.0264___41____68_____7.643__0.75___7.66%_____170_________10.01% Falcon 900**__.0220___46____87_____7.65___0.76___6.94%_____200_________7.61% Falcon 50**___.0181___41____77_____7.59___0.90___5.81%_____190_________6.68% Gulfstream III__.0264___34____75_____6.48___0.80___8.05%_____185_________9.50% Gulfstream IV_.0264___45____78_____6.26___0.86____7.90%____185_________9.35% Gulfstream V__.0249___41____78_____7.69___0.85___6.96%____180_________8.56% Hawker 400___.0200___45____68_____7.85___0.72___6.71%____185_________8.04% Hawker 800___.0215___44____75_____7.06___0.80___7.34%____190_________8.51% Jetstar III_____.0239___43____79_____5.27___0.70____9.08%____210_________9.63% LJ31________.0249___42____62_____7.20___0.80____7.42%____165_________10.13% LJ35________.0220___40____72_____6.17___0.80____7.53%____190_________8.67% LJ45________.0215___43____66_____6.72___0.80____7.14%____180_________8.75% LJ60________.0293___53____89_____7.25___0.75____8.29%____195_________9.72% Westwind 2__.0220___40____77_____6.51___0.72____7.73%____200_________8.67%
*Used max W/S for performance data. **These jets must use the 3TW gauge for three engines.
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Post by Tom Goodrick on Sept 13, 2008 10:20:34 GMT -5
This is a new topic on flying jets. It is basewd on a new equation I worked up as a minor revision of an equation that has appeared in aeronautical engineering texts for many decades.
The significance of the new performance equation is that it gives thrust/weight ratio required to fly a particular indicated airspeed and is independent of altitude. Previous published versions had always show T/W versus true airspeed althoung this was unnecessary and brings in altitude dependence where there is none! Of course the amount of thrust you can get is a function of speed and altitude. To make it easy to use this equation, I have developed a gauge that shows the thrust/weight ratio on the panel at all times. You simply adjust the throttles until you see the desired thrust/weight ratio. Bear in mind that in a jet the weight varies continuously during flight. In real life the gauge would work with current engine management computers to present instantaneous information.
Here is the equation:
T/W = (CD0 * Vk*Vk) / (194.8 * (W/S)) + (93.84 * (W/S)) / (e * AR * Vk * Vk)
where Cd0 is zero lift drag coefficient from part 1100 of the air file, Vk is the indicated airspeed in KIAS, (W/S) is the wing loading or weight over wing area using data from aircraft.cfg file as are e and AR, e is Oswald's Efficiency factor (0.6 to 0.9) AR is wing aspect ratio (b*b / S).
I will post a table for 25 aircraft of these parameters.
This equation can be put into a spreadsheet showing a graph of T/W versus KIAS for the range from 100 to 380 KIAS. That graph shows a curve that starts moderately high, decreases to a minimum, and then generally increases toward the high speed end. You have to be careful with the wing loading because that varies considerably as fuel is burned. I present a minimum value based on empty weight and a max value based on max gross weight. You can look at values within this range.
A value of T/W near, or just faster than the minimum, can be held constant as you climb for best results. At high altitude, your choice of speed and T/W is very limited because you must have more than the minimum amount of thrust/weight and yet stay below the max indicated speed (VMO) or the max Mach number (MMO).
I'll send an Excel file and/or the T/W gauge to anyone who requests it by email.
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Post by Tom Goodrick on Sept 13, 2008 9:49:02 GMT -5
Hey Ed, congratulations to you and the Missus on becoming Grandparents. We'll expect a handsome young pilot named Toby to be buzzing around pretty soon! The fact he came early just means he's eager to get going!
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Post by Tom Goodrick on Sept 9, 2008 17:04:18 GMT -5
Bill, I think its great that you have an interest in doing something like that. But I'll put in my 2 cents against it because first, I owned a motorhome for several years and know what is involved, and second, haviing recuperated from surgery too, I'd hold off a while until you are real sure you can handle something like that. Motor homes art not always the best riding vehicles. Most of them start out as trucks so keep that in mind. I figure it would take you 65 hours at a minimum. That's a lot of sitting on a moving seat you are not used to. If you are not familiar with the motorhome from taking many short drives around home, you will have a high level of anxiety as you worry about its handling (it is very easy to dump one on its side when you encounter strong winds or sharp curves or both. Clearing traffic for turns when off the freeway can be a hassle.
Third, in today's gas market, a motorhome could be a nightmare. Mine got 3 mpg and had only an 18 gallong tank. I was looking for the next gas station just as I left each one. Finding open stations after 9 pm has become a big hassle most places. It might be better on Interstates.
It might be best to fly to a city in Alaska and then rent a motorhome there for sight-seeing.
Are you ready to change a truck tire - a dual, 24 inch truck tire? It's a lot of work and a lot of squatting.
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Post by Tom Goodrick on Sept 9, 2008 9:59:52 GMT -5
Sorry, Hans, you are missing the point. I cannot provide you with an explanation of the physics because there IS NO EXPLANATION for cooling of inanimate objects.
My only explanation here is that who ever designed the Bell 206 gauge, inserted some code that gives an erroneous cooling effect. It is binary code in the .gau file so I can't read it. (I no longer have a suitable dissassembler.)
The Ambient temp gauge I wrote sees no effect of speed. It simply reads the ambient temperature.
When you reach about Mach 0.8, the real world imposes a slight discrepency on temperature gauges because of the shock wave field that develops locally on parts of the aircraft where such a probe may be located. Various ways have been worked out to get an accurate reading. The ambient temperature changes across a shock wave. Flow around a leading edge, a fairing or a nose, may be accelerated above mach 1.0 when the "freestream Mach" is 0.8 or higher. But this is nothing like what the Bell 206 gauge shows at 150 knots! That gauge is just plain WRONG.
I am sending you a copy of the ambient temp gauge so you can try it. The above article was written in April of 2007. Very few, if any, people ever asked for it. It is an msl gauge so I'll send you the text source code. Change the extension from .txt to .xml and it becomes the working gauge code in XML.
Ambient parameters of the atmosphere exist at some considerable distance from any part of the flying aircraft. "Local" parameters are in the flow field surrounding the moving aircraft. Above Mach 0.8 there may be local variations caused by shock waves. These become very significant at higher speeds. At speeds of Mach 2.5 and above there is aerodynamic heating and we begin to see changes in the chemistry of the air. At Mach 10 or above, the air near the nose or leading edges becomes hot enough to melt most materials. But nothing of this sort happens at low subsonic speds - either heating or cooling.
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Post by Tom Goodrick on Sept 8, 2008 22:48:05 GMT -5
NEW AMBIENT TEMPERATURE GAUGE FOR JETS « on: Apr 22nd, 2007, 10:11pm » Quote Modify Remove
-------------------------------------------------------------------------------- I have noted recently that J Mac McClellan, editor of FLYING, is always talking about how much the temperature in C varies from "standard" when he tests jets. He claims this causes serious performance changes over what you would get in standard conditions. I decided to look into this. The first thing I found was thet the temperature gauge I have been using on all my panels for all my aircraft is no good for jets. It is from the Bell helicopter and shows the temp in F when you are parked. That is fine for telling you whether to zip up your jacket before leaving the plane. I didn't know if there was a better gauge so I decided to make one. Then I tested it and found that there is indeed a big need for it in the jets. The main problem with the other gauge is that it is strongly affected by airspeed, particularly when used in jets. Here is an example of one test. This was done at 20,000 ft using a Learjet 35. KIAS F (Bell) C (AMB) 300__25____-24.1 250__14____-24.1 200___6____-24.2 150__-1_____-24.2 The conversion from C to F is F=32+9*C/5. Obviously these readings from the Bell temp gauge are total hogwash. I did set both gauges in a parked aircraft in different weather files and found they agreed according to the conversion formula: _F___C 92___33.86 75___24.36 62___16.90 56___13.76 (normal day at 630 ft msl) 32___0.00 10___-11.7 0____-17.3 Obviously a key thing to note when going up and down through clouds is when the temp drops below 0 C as that is when you pick up icing. This occurs on nearly every flight you make in a jet regardless of the season. Now as to the performance variation of a jet when it is a few degrees warmer than normal. J Mac has proclaimed (10 C warmer than standard) as a factor in the degraded performance from book values. The actual equation for this is The thrust ratio is: T/T0 = (2457+9*C0) / (2457+9*C) where the 0 denotes standard conditions at whatever altitude you are flying. The only direct consequence of the non-standard temperature is the change to the thrust level T from the thrust level T0 you would get with the same throttle setting at the same altitude in standard conditions. The equation does show a dependency on the pressure ratio but this is the same becuase you are at the same altitude as indicated by the altimeter which is showing the same pressure ratio. Working through this equation, a 10 degree C increase in temperature will cause a 4.4 percent decrease in the thrust. Big hairy deal. Increase the throttle by 4.4% and you get the same speed with a slightly greater fuel flow. Well at least now we can all experiment to see how the performance does change and what our options are as pilots to deal with the situation. I have put this new gauge on all my jets and will be keeping track of what changes I see in speed or fuel consumption. I have a large number of weather files to work with covering a wide range of weather conditions. I have put a little 2k zip file on my web site tonight that you can download to get this file (AMB_TEMP_C.XML). Here's a short list of standard temperatures for some altitudes that are often used with light jets. ________Book*__FS9 (Calm Weather) 41,000 ft -55C___-56.1C 40,000 ft -55C___-56.1C 36,000 ft -55C___-55.9C 35,000 ft -54.3C__-53.9C 29,000 ft -42.5C 28,000 ft -40.5C *Perkins and Hage, 1965 There are many forms of "The Standard Atmosphere" with minor variations. All show a transition starting at about 35,000 ft to a constant temperature profile. How well that works in real life I don't know. It will be interesting to find out. In FS9 the temp appears to be constant at -56.1C from 37,000 ft up. This leads to the simplified equation: T/T0 = 1952 / (2457+9*C) This will show a variation of just under 5% in thrust ratio for a 10 degree C variation in temp from "normal" of -56.1C. In a much more complex equation the speed that results from changes in both thrust and weight can be seen but the variation is not clear and is rather meaningless because you can either set normal thrust and take the normal fuel flow with a slight reduction in speed or dial up the thrust to keep the normal speed. You lose a little when it is warmer than normal and gain a little when it is colder than normal. « Last Edit: Apr 23rd, 2007, 10:19am by Tom Goodrick » 216.180.4.187 Tom Goodrick Administrator
Simaholic
Posts: 3589 Re: NEW AMBIENT TEMPERATURE GAUGE FOR JETS « Reply #1 on: Apr 26th, 2007, 3:57pm » Quote Modify Remove
-------------------------------------------------------------------------------- I have collected a bunch of temp data and performance data in various temperature conditions. There is something important that the thrust ratio equation misses. The true airspeed will be higher if the temperature is higher at a given altitude. This can cancel the effect of the lower thrust. I'll present the temp data when I get a chance to type it up. Meanwhile, consider this. If we are interested in the performance of a particular aircraft in various conditions, we should keep a more complete flight data log such as the one shown below. I have been working with this today and find it fairly practical. I keep it minimized on the bar under the panel and make entries as I fly. The temperature must be read without pausing the sim. FLIGHT DATA LOG: DATE 4/26/07 4/26/07 RW Used? Y Y ATC Used? N N AIRCRAFT Pip Mer Ces Must * FROM KHSV KHSV TO KAHN KAHN DISTANCE 178.4 178.4 START FUEL 135 286 PAYLOAD WT 780 780 GROSS WEIGHT 5054 8048 CG POSITION 28.06 23.08 Surface Temp C 19.34 19.53 START TIME 9:26 9:28 CRUISE DATA: CRUISE ALTITUDE 15000 25000 OAT C -6.1 -26.1 THRUST/POWER 60 48 KIAS 173.8 248.6 MACH 0.35 0.6 KTAS 219.7 361.6 KGS 249 395 Fuel Flow pph/e or gph 205 401 NMPG 7.21 3.01 FLIGHT HEADING 104 103 START WIND DIR 228 233 START WIND SPD 46 59 LATE WIND DIR 218 227 LATE WIND SPD 43 56 END DATA: FLIGHT TIME (min) 52.1 36.24 LANDING KIAS 70.91 88.29 LANDING FPM -165 -98 Surface Temp C 21.95 22.75 END FUEL 105 179 FUEL USED 30 107 Block Speed: 205.5 295.4 Block NMPG 5.95 1.67 Notes: Broken Cu Tail Wind Scat Storms * Aircraft are the Piper Meridiam single-engine turboprop and the Cessna 510 Nustang twin jet. « Last Edit: Apr 26th, 2007, 4:02pm by Tom Goodrick » 216.180.4.140 Tom Goodrick Administrator
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Posts: 3589 Re: NEW AMBIENT TEMPERATURE GAUGE FOR JETS « Reply #2 on: Apr 26th, 2007, 9:00pm » Quote Modify Remove
-------------------------------------------------------------------------------- Air Temperature at Various Altitudes in FS9 All Temps Deg C Alt_ft____Clear Wx__1/16/07__4/16/07__7/16/06__10/16/05 12k_______-8.55____-15.1____-1.41_____7.96_____-0.26 16k______-16.6_____-21.1___-10.0_____-0.33_____-8.17 20k______-24.4_____-27.2___-19.1_____-9.38_____-15.8 24k______-32.2_____-34.4___-28.0_____-18.5_____-24.0 28k______-40.0_____-40.7___-37.5_____-27.9_____-34.3 32k______-47.8_____-46.1___-46.0_____-37.5_____-42.9 36k______-55.9_____-49.0___-49.4_____-45.2_____-47.9 40k______-56.1_____-50.0___-49.5_____-49.2_____-49.7 44k______-56.1_____-50.0___-49.4_____-49.0_____-49.9 The "ClearWx" condition is supposed to be a "standard" condition but I don't know what standard it might be. It does not agree exactly with the standard conditions I have in books but it is not far off. I have not checked it against some of the "standard atmosphere's" I used at NASA. (I had to include six in an orbital/aeronautical sim I wrote but those started at 20 km altitude and ended at 120 km. I only carried the density values in the data base because that is what causes aero-thermal heating.) The one thing that bothers me about these tables is that they show the constant temperature region above 35k is different for the Clear Wx compared to all the RW files. All the RW files are about 6 deg C warmer in that high altitude region than the "standard" file. I started to run a comparison of performance using the Cessna Mustang I've been working on. I cut the study short and will show only the comparison of one condition - a full load (all seats filled with adults+overnight luggage) at 28,000 ft in the "Clear WX" compared to the July RW file. At 28,000 ft, the July air is warmer by 12.1 deg C. Here are the results: _______Clear__July Thrust__50%___50% KIAS__240.8___244.1 Mach__0.61___0.61 KTAS_362.7___375.5 pph/e__389____387 NMPG_3.12___3.25 Warm air seems to improve speed while using the same thrust and getting the same fuel flow. « Last Edit: Apr 26th, 2007, 9:01pm by Tom Goodrick » 216.180.4.173 Pages: 1
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Post by Tom Goodrick on Sept 8, 2008 22:39:58 GMT -5
Different Airfiles -- Various parameters « on: Oct 31st, 2007, 3:39pm » Quote Modify Remove
-------------------------------------------------------------------------------- I've looked at various airfiles and found something I should have found out a long time ago. They don't contain the same entries! I wanted to get to the source of the engine parameters but it seems like comparing apples and oranges. Since all of these airfiles 'fly' they do contain what's required. Elaborating on the above, some have an FS98 Engine section. This could mean that they're old. However, even FS2004 airfiles have entries that are listed as being disabled in FS9. Thus, they're carried over as relicts from FS7 or FS8 but don't effect anything anymore. From a designer point of view it may be prudent to start out with a recent airfile. This way we ensure that we're spending time on tweaking one that contains all of the current parameters. Regarding the aircraft.cfg Tom has adviced me to dump other people's attempts and start from scratch. While I see the point in not being confused by erroneous entries there are at least a few sections that we don't have to do over. Provided the visual model sits nicely on the tarmac there's no reason to redo the the section on gear position, height and default angle. Moreover, there may be electrical parameters, the autopilot section and more that work as intended. Most mistakes are found in the MOI section, the primary aerodynamics section (wing length / area and so on) and in the engine perfomance section. Until we got Tom's power panel it was anyone's guess what performance we really got. I've tested a few aircraft that deviate considerably from the rated power specs. Some are payware aircraft that have been praised on all major flightsim sites for their outstanding adherence to realistic performance. Anyway, this thread should mainly focus on the airfile. Since they seem to come in different flavors we should be concerned which sections a 'modern' airfile ought to contain to be worth any effort. « Last Edit: Oct 31st, 2007, 3:41pm by Hans_Petter » 84.49.151.53
-------------------------------------------------------------------------------- best regards,
Hans Petter Tom Goodrick Administrator
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Posts: 3589 Re: Different Airfiles -- Various parameters « Reply #1 on: Oct 31st, 2007, 7:08pm » Quote Modify Remove
-------------------------------------------------------------------------------- The part of the FD we should concentrate on here, from what you have said, is the aircraft.cfg file. In all the areas you have mentioned, that is the only file that counts. The air file can be ignored in these areas. You have no pure FS98 files flying in FS9. They may have started out that way, but when you moved them up to each successive version, little conversion programs operated on them to bring the air file as up to date as was needed and bringing the aircraft.cfg files fully up to date. One thing about the aircraft.cfg file is that its lines can be listed in any order and the file still works. You cannot take a line from one part and put it in another part. But you can move the parts around and move the lines around within each part. Indeed there are parts that are completely ommitted. The main part like that is the [flight tuning] part. That is considered optional by Microsoft. Of course, they thought they got it completely right the first time! But it is often necessary to copy in a [flight tuning] part from another aircraft. Some parts will be automatically replaced if you erase them. For, example the brake part can be erased and will reappear when you next fly the plane and then look at the file. The Aircraft Container SDK helps with this in that it shows all the possible parts and all the possible lines that can be in a part. It is the responsibility of each of us to try to keep the order of the aircraft.cfg file relatively uniform and to be sure that all necessary lines are included. One thing I have found out the hard way is that when a part is duplicated, the version nearest the end of the file is the only one that counts. I spent a lot of time adjusting some scalars once in the [Flight Tuning] section with absolutely no effect. Then I discovered the second section farther toward the end of the file, threw it away, and all was well. 216.180.4.187 BudsBud Member
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Posts: 131 Re: Different Airfiles -- Various parameters « Reply #2 on: Nov 1st, 2007, 11:04am » Quote Modify Remove
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Different Airfiles -- Various parameters As Hans said if it were not for Toms Power Panel I would not have had any idea that my B-314 was so far out of specs. No wonder that the bird took off like a rocket. I am showing 2000+ hp @ 1500 Rpm 27” MP and at 85% throttle she over speeds and over- stress the plane BAH! I think we should show 1600 hp at 2700 Rpm with about 40+ “ MP Can I find the B-314 power /prop specs for this bird. What other plane uses The Wright GR2600 engine. 24.110.4.48 Tom Goodrick Administrator
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Posts: 3589 Re: Different Airfiles -- Various parameters « Reply #3 on: Nov 1st, 2007, 8:01pm » Quote Modify Remove
-------------------------------------------------------------------------------- I found some data in Jane's Fighting Aircraft of WWII on the Wright Cyclone GR2600 series. The A model gave 1600 at military power, the B 1700 and the BB 1900. There were 14 cylinders. They give a displacement of 2603 cu in but I don't know if that is total or per cylinder. the compression for the A was 6.3 to 6.85 for the models. The gear ratio was 0.5625. Try adjusting the inputs and see if you can get 1600hp. But it might fly better at 1900 and that would not be unreasonable. I don't have prop specs. 216.180.4.163 Chris_Ross Member
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Posts: 215 Re: Different Airfiles -- Various parameters « Reply #4 on: Nov 2nd, 2007, 2:57pm » Quote Modify Remove
-------------------------------------------------------------------------------- Boeing 314 Brewster SB2A Buccaneer Curtiss SB2C Helldiver Douglas A-20 Douglas B-23 Dragon Grumman TBF Avenger Lioré et Olivier LeO 451 Martin Baltimore Martin Mariner Miles Monitor North American B-25 Mitchell Vultee A-31 Vengeance The book I have says they added 1200 USG fuel to 5400 USG and increased the size of the propellors with the upgrade to 314A but it doesn't mention the sizes « Last Edit: Nov 2nd, 2007, 3:09pm by Chris_Ross » 121.209.233.117 Ed_Burke Member
It's fun that keeps us alive; not healthy living!
Posts: 434 Re: Different Airfiles -- Various parameters « Reply #5 on: Nov 3rd, 2007, 4:28am » Quote Modify Remove
-------------------------------------------------------------------------------- If it was 2603 cubes per pot I want to be there when they light the fuse. Ed 58.104.170.187
-------------------------------------------------------------------------------- ED B Tom Goodrick Administrator
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Posts: 3589 Re: Different Airfiles -- Various parameters « Reply #6 on: Nov 3rd, 2007, 10:26am » Quote Modify Remove
-------------------------------------------------------------------------------- I fixed up my Boeing 314 so it gives the right power. But with that low power setting (1900) it will not start moving in the water. Water drag is far beyond our control. If you have something that works, stay with it! I had to boost power by 1.2 and thrust by 1.8 to get moving. To get the right power, I put in: cylinder displacement = 185.93 compression ratio = 6.3 number of cylinders = 14 gear reduction ratio 1.778 //recip of 0.5625 « Last Edit: Nov 3rd, 2007, 10:30am by Tom Goodrick » 216.180.4.223 Hans_Petter Member
Posts: 424 Re: Different Airfiles -- Various parameters « Reply #7 on: Nov 3rd, 2007, 3:56pm » Quote Modify Remove
-------------------------------------------------------------------------------- I just edited some useful engine parameters for the old prop aircraft that I've been playing with. The tables are 508, 509, 511 and 512. When these agree with the rpm and the beta range in the aircraft.cfg the power scalar is next to obsolete. We haven't been too focused on engine sounds versus rpm. However, when these tables are set to agree with the specs the engine sounds are more correct for the range of rpm. This indicates that the tables should be in the ballpark before we adjust the power with the power scalar. For starters, check that the graphs in the airfile covers the entire range of rpm / beta for your aircraft. For instance, table 511 gives prop efficiency versus beta pitch. Some airfiles list the range from 15 -30 and some go to 35 or 40. If your aircraft comes with a beta max beyond 30 in the aircraft.cfg the table 511 ought to have a curve that covers the upper range. It may be possible to add entries to the tables 511 and 512 but I don't think AAM will do the job. The other tables can be altered to cover the upper rpm range in case your aircraft requires a higher maximum value. 84.49.151.53
-------------------------------------------------------------------------------- best regards,
Hans Petter BudsBud Member
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Posts: 131 Re: Different Airfiles -- Various parameters « Reply #8 on: Nov 3rd, 2007, 4:21pm » Quote Modify Remove
-------------------------------------------------------------------------------- ED Boy that was a good one:>) The specs that I found on the net indicate what Tom has: Total Dispalcement 2603 Cu" Cyl Displcment 185.9285 Comp Ratio 6.3:1 HP @ TO 1700 @ 2600 RPM Looks good 24.110.4.48 Ed_Burke Member
It's fun that keeps us alive; not healthy living!
Posts: 434 Re: Different Airfiles -- Various parameters « Reply #9 on: Nov 4th, 2007, 4:55am » Quote Modify Remove
-------------------------------------------------------------------------------- We had a PBY-5A around the Aussie traps years ago doing magnatometer work with two of those babies making the noise. It had some mombo. Ed 220.237.212.26
-------------------------------------------------------------------------------- ED B Tom Goodrick Administrator
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Posts: 3589 Re: Different Airfiles -- Various parameters « Reply #10 on: Nov 4th, 2007, 8:42am » Quote Modify Remove
-------------------------------------------------------------------------------- Hans, I don't think you should do anything with those tables you mention. 508 is torque coefficient vs RPM. It is flat at 0.49 in the range of flight RPM. The most you could do would be to extend it to cover your max RPM. But I don't think that will accomplish anything because the sim interpolates linearly between all points in tables and automatically extands the left-most point. 509 is Engine Turboprop Friction Torque vs RPM. The most you could do is extend RPM. 511 shows curve of prop efficiency vs Advance Ratio for several values of prop beta angle ranging from 15 to 40 degrees. You can't do anything to these curves. They are too complex. Advance ratio is 101.2*KTAS/RPM/Diam. All you can do is make sure you allow min beta below 15 and max beta at or above 40. I like to use 10 to 45. These are the limits set in the aircraft.cfg file. While flying several aircraft recently with the PowerPanel, I have watched prop beta. It starts at the lower limit and moves up to about 30 during takeoff and stays there during most of the flight. On a turboprop I saw it go up to 40 as I was cruising at 20,000 ft on 80% power. That is the highest I have seen it. (That was with a limit of 45 degrees.) 512 is power coefficient vs advance ratio for several values of beta. The same considerations apply as above. You certainly cannot mess with the y values of these. You can only make sure you allow a range of beta as wide or wider than the range shown. All I can say is that the standard values seen in these tables do not screw anything up. The file for that souped up R4D you are working with has been badly screwed up. Do not use it as an indication of what should be done with air files in general. When I am confronted with a screwed up air file (it has happened many times), I dump it and put in an air file for a similar aircraft that behaves well. When you do that, there are only a few things in the .air file that need adjustment. Everything else is handled in the aircraft.cfg file. If you want to improve the sound, work on the sound.cfg file to emphasize certain .wav files. The SDK has some info about this file too. « Last Edit: Nov 4th, 2007, 9:17am by Tom Goodrick » 216.180.4.44 216.180.4.105 Hans_Petter Member
Posts: 424 Re: Different Airfiles -- Various parameters « Reply #11 on: Nov 4th, 2007, 2:20pm » Quote Modify Remove
-------------------------------------------------------------------------------- I assume what I did was exactly to fix something that had been screwed up badly I used an airfile that Tom G had edited for a standard DC-3 for reference. Some of the torque and power curves were very different before I tweaked them. Tom, if you never touched these curves I guess I replaced "mine" with standard FS curves. Then I extended anything pertaining to my higher max values to cover the extremes of "my" aircraft. The proof of the pudding is that a power scalar of 1.1 is all that I need now. It used to be 0.62 to get the rated horsepowers and I suspect that the relations between power, rpm and prop advance (beta) were off. Hence, a power scalar may not produce a well-balanced power plant even though it gets the hp right. While the scalar is a nice tool for fine-tuning it should be viewed as an indication of underlying problems when it takes extreme scalar numbers to obtain rated specs. « Last Edit: Nov 4th, 2007, 2:21pm by Hans_Petter » 84.49.151.53
-------------------------------------------------------------------------------- best regards,
Hans Petter Tom Goodrick Administrator
Simaholic
Posts: 3589 Re: Different Airfiles -- Various parameters « Reply #12 on: Nov 4th, 2007, 7:44pm » Quote Modify Remove
-------------------------------------------------------------------------------- There are so many things in an .air file that we do not know much about that I consider it a waste of time to dig deeply into it. Prop advance ratio is not the same as beta. They are related but only in that they are both independent parameters against which prop performance is displayed. Prop advance is 101.2*V/RPM/Diam with V in knots, Diam in feet. Perhaps removing the water boost had something to do with reducing the excessive power. The original intent of this thread was to discuss why airplanes seem to fly similarly when they contain different settings in the FD files. In most cases the answer is that differences in the .air file are cancelled by corrections in the aircraft.cfg file. But in other cases the explanation is that we just don't see the differences. Using a program like Bud has given us that puts flight data into Excel sheets is one way to show these differences. By conducting an experiement intended to highlight the differences and recording the data, we can have some charts to aid the discussion. Bud's lates version records any of the parameters listed in the Panel SDK which includes engine power and several engine performance indications as well as the control inputs and flight performance values associated with the experiment. 216.180.4.214 Pages: 1 Reply Notify of replies Send Topic Print
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