Post by dirtydog1006 on Aug 31, 2010 14:42:34 GMT -5
Finding good models is like dating: One catches your eye, you download it and fly, and often you want out pretty quick.
But even the keepers are driving me nuts because they load up with too much nose-up trim (at least IMHO). Part of my TO checklist is to crank about 12-15 clicks of nose-down before I start the TO roll. I get what seems to me better realism this way.
But I wanna be lazy (and therefore a more realistic pilot?) and hard-wire my fav ships for a decent trim setting at load up. I've looked though the AIRCRAFT.CFG file, and messed with H-TAIL-INCIDENCE. Actually, I pushed it pretty hard, in one case from the designers 3.2 to 10! Seemed to have no noticable effect at all. I do not see any other obvious place in the AIRCRAFT file to try to make my dream come true.
Must I explore the mysteries of the AIR file, or am I missing some simple fix?
Thanks for all the help. I know I am asking a lot of questions lately, and will try to cut down. But it;s so interesting........AND I get useful answers here!
Post by Tom Goodrick on Aug 31, 2010 19:19:00 GMT -5
I don't understand why you are having this problem. Most planes I have encountered need just a little nose up trim to fly off the ground nicely when they reach the proper airspeed.
I'll be glad to help you with this sort of thing. But I need a few answers first.
1. Do you have any real pilot training? 2. Have you tried flying any of the default aircraft that came with your sim? 3. What types of aircraft are you trying to fly?
You are correct in that of the many aircraft available as downloads, very few are properly set up. Designers are better at making models look good than at making them fly.
If you poiint to the icons under my photo, you'll see one of them gets you my email address. I see yours is blocked. If you send me an email, I will send you two gauges that will help you. One is a trim gauge. It shows the trim setting in degrees with a decimal point. That is how I set up my planes for takeoff. The second gauge is a weight and CG gauge. Before any takeoff a real pilot makes sure the weight is below the limits and the CG position is within a safe range. When flying a new aircraft, these are not guaranteed. Fancy aircraft have both a max takeoff weight and a landing weight.
For a first flight in any aircraft, turn off the weather and set the weight below the landing weight limit or at about half fuel with only two crew (pilot and copilot/instructor). Know what the safe takeoff speed is. It should be 1.3 times the stall speed in the takeoff configuration.
I make takeoffs with very little pitch input but with some. In some cases I hold forward stick to void an early lift-off. But with proper trim, the plane lifts off without pitching up too much and climbs out. It may need a little nudge (back stick) to rotate but not much. Then you trim it for climb. You maintain takeoff power until 400 ft above the ground and then ease the power back to continuous climb power (about 80-85% power and, yes I have a gauge that shows you the power.
Pick one plane - perhaps the Cessna 182 Skylane - and fly that plane for several hours, learning to do all required maneuvers including takeoff, climb, turns to headings, doing that while maintaining altitude, changing from cruise to descent mode, lining up and making smooth landings. The 182 takes off and lands 80 KIAS (knots indicated on the gauge), cruises at agout 135 KIAS, descends at 100 KIAS, and lands nicely at about 60 KIAS with full flaps.
By turning off the weather (select clear skies) you will know that whatever the plane does, it is responding to only your control inputs.
Flying a plane like the Skylane gives you time to sort out what you need to be doing during critical phases like takeoff and landing. In other planes like jets, there are more things to worry about and less time to do them as everything happens much faster.
Post by Tom Goodrick on Aug 31, 2010 23:28:31 GMT -5
One thing I should stress is that, since this is relatively new to you, you should find an aircraft model that is soundly designed and known to behave well and stick with it for long enough to develop all your skills in FS flying.
There are many things that can make aircraft of dubious quality hard to handle. There are fixes for almost all of these bad features but they are somewhat complex. What may seem a direct solution like your adjustment of the tail incidence will have very bad consequences you have not foreseen. Among the other things that can be wrong with a design are bad CG position and/or main gear position. These can make it hard to rotate the nose up for takeoff so that you tend to over control and point the nose too high.
Another thing is that most real pilots do not move the pitch control a large amount except in emergencies that seldom occur with proper pilot technique. There is often a slight back pressure to rotate for takeoff but then trim takes over to smooth out the climb as various things like gear and flap changes perturb the fligth path. Similarly, on the landing approach, trimming is done while gear and flaps are deployed so that only a slight back nudge on the stick accomplishes the flare which is held to touchdown. There is seldom any need for jockying the stick fore and aft.
The trim position for takeoff can be determined on a first takeoff if you have a long runway by gradual adjustment by holding the plane at a proper speed for flight. You must make a note of the position of the trim indicator when liftoff occurs so you can repeat that (or note the value on my trim gauge). The most direct fix if there really is a trim sensitivity problem is either the "blind" adjustment of the elevator trim scalar in the Flight Tuning section or a direct adjustment of the plus and minus trim limits. These are both in the aircraft.cfg file.
There is nothing to be gained by going into the .air file. All necessary adjustments for this problem can be handled in the aircraft.cfg file. But you must not hurry to make an adjustment you are not sure about. If you do, note the original values you change so you can return the file to its original state.
There are several ways designers of real aircraft achieve pitch trim. A particular way is chosen based on the experience of the designer and the weight or complexity of the installation. The way it is done in FS is a valid way and is an easy way to understand. When you move the stick full forward and full aft, it rotates the elevator through a prescribed range of angle. Setting the pitch trim control moves the center point of that range of elevator angle. There are some old designs such as the Piper Cub and some new sophistcated designs like jet airliners that use the same method. But whatever the method used in a real airplane, the trim effect can be simulated in FS by the method they chose.
One thing to be aware of is that while low speeds require large angular changes in the elevator just to change speed, at high speeds near cruise, very small angular adjustments must be made very smoothly or you will go bucking wildly along the intended path as though riding a bronco. "Speed stability" is what is needed to smoothly lock onto a particular cruise speed. Mess this up and flying can be very difficult.
Post by Tom Goodrick on Sept 1, 2010 10:10:01 GMT -5
I just made a takeoff in my C182. It has a few custom aspects in its FD files but they pertain mainly to cruise and to stall, not to this phase of flight.
I set the trim at 7.0 degrees nose up and kept it straight on the runway at full throttle with the rudder pedals. It lifted off with no stick input at 75 KIAS. It reached about 90 KIAS as it started to pitch up to follow the flight path. It did a little phugoid, giving me a very mild roller-coaster ride that I would normally avoid with slight nudges to the stick until the forces balance in climb. But it looked like a normal takeoff.
the payload was two 200 lb people up front and two 150 lb people in back with 40 lbs of luggage. We could have carried another 30 lbs of luggage. The takeoff weight was 3072 lbs and the CG was at 22% which is normal. I carried only 67% fuel to stay under the max gross weight of 3100 lb.
Post by dirtydog1006 on Sept 2, 2010 12:00:01 GMT -5
Tnanks for the info, Tom. To answer your questions: 1) I went through ground school (sucessfully) and have a few hours in an L-16, but both a long time ago. 2) I really have not used the default planes much, except the 172. I will play with the 182 per your suggestions. 3) Mostly I fly Rick Piper's Chipmunk, and lately a C-150F (forget the designer's name, but not the L model that so may rave about.)
Here's the problem. I do not start cold and dark, but at idle at the end of the runway. Usually it is KBOS 4R. I am careful about the weight and balance, insofar as messing with the fuel and payload allows. One notch of flaps and advance the power. She lifts off about right, and I intend to hold 100% power until about 400-500AGL. We're doing about 800-1000 fpm. If I have not cranked in nose-dowm trim, but left it alone per designer, then even if I back off on the power she just keeps rotating up to an unrealistic angle.
I realize that the trim must be adjusted as speed increases, because the forces change. But I got to hit the nose-down button a heck of a lot of times. Maybe the problem is I have too fine an increment on the stick trim switch. That just occurred to me as a possibility. Is that adjustable in FS9?
I would love to have your power and trim gauges, but could not make the forum reveal your e-mail. Are those gauges not on your web site? I am sure many people want them.
Anyway, I will play with the 182, keeping your info in mind, and see what marches.
Post by Tom Goodrick on Sept 2, 2010 19:44:35 GMT -5
You get my email directly by clicking on the central of three small icons under my photo. The left icon gets you to my web site.
But you must be logged in as a member for those icons to work.
I am familiar with BOS as I lived in that area for 20 years before I wised up and went South. I flew a C172 out of Hopedale.
With the 182 you can easily travel all over that area from Long Island to Maine with side trips to New Hampshire, Vermont and upstate New York. You should put some hours on all the planes you were given with the program. They are pretty well done. I have modifed their FD files but only over little things like adding or subtracting a knot or two in cruise or turning them into killers when you treat them poorly. The Mooney is a good experience in flying high but descending slowly (because it does not have pressurization). The Baron is a very good twin with a fine payload capability. The King Air 350 is a fine example of a turboprop when you are ready for that. The Learjet 45 is a good bizjet for after you have a lot of experience with the Baron and King Air. The airliners are good when you get ready for them.
This is a fairly realistic sim. You have to work your way up to the higher performance aircraft or you will get very frustrated.
But the only one you can trust to prepare good flight models is Microsoft. I do a decent job on the ones I work on.
It is glaringly obvious that you have some very bad models. But you said you flew the C172. It was not as bad as the Chipmonk, was it?
Take a moment to check your stick calibration. Adjust the trim wheels on your stick only if needed to center the indicator on your calibration screen. You might want to expand the dead zone just a little fo your stick is not too twitchy. Overcontrolling is a common problem for beginners. Also, controlling when when you don't need to is a common problem. If you have the weight within reason as you mentioned, then setting trim a little below neutral (ie- more nose up) should be all you need to fly. When you get my trim gauage, put it on all your panels. (That is just a matter of inserting a few lines in the panel.cfg file. (All .cfg files are text files that can be edited with NotePad.)
What kind of control device do you have - a simple stick (I hope) or a fancy yoke? It sounds like you have one of those programmable buttons for trim. Did you notice that when you set that up you have to pick a setting for the number of repeats allowed (which determines the sensitivity of your trim inputs)? Otherwise the trim input code will only allow one increment of change per cycle of the sim even if you hold the trim button down.
Now that I mention that stuff, it is clear that could be your problem. Work it out on the C182 before getting fancy with an aerobatic taildragger.
Any trim adjustment you make to get the Chipmonk flying (I'd leave it alone until you get some experience with the C182) are in the aircraft.cfg file. The simplest adjustment is to change the scalar number for the elevator trim in the Flight Tuning section. (If you don't see that section in the Chipmonk's file, copy the complete Flight Tuning section from one of the default aircraft. To get more involved, you might consider the deflection range of the elevator or the limit of the elevator trim which are both in the aircraft geometry section. Before doing anything to the Chipmonk, set the H-Tail_Incidence back to 3.2. It does have some effect. But these others are the proper things that may need changing in a poorly-done flight model.
You don't have to own a lot of airplanes to have fun with this sim. By learning with the default planes, you will know what to expect from a model in each category of aircraft. With a lot of airplanes you just get distracted trying lot of different ones and never get very good at flying any one of them. I prove the truth of that just about every day. I just switched over to a laptop running FS2002 because this old desktop is on its last legs. Now i have too many aircraft on my laptop!
I wont tell you that you can have more fun in my Aerobat than in the Chipmonk and yet you can land with a nosewheel. But that is for when you get 50 hours in the 182 and a few in the Mooney.
Post by Allen Peterson on Sept 10, 2010 20:17:47 GMT -5
Hi DD, What Tom says is all good stuff. But, if you have some reason to modify a mini panel you might think about this. If you look in the panel folder for the Cessna 172 and open the panel.cfg file you will see at the top [Window Titles]. You will see that Window05 is a Mini Panel. If you scroll down to [Window05] section you will see a list of gauges which you can move or change as long as they will fit in the size_mm frame. So you are happy with these changes when flying the 172. Now when you fly the 182, of course, you get the stock mini panel. Now you have two options. One is to make all the changes in the 182 [Window05] that you made for the 172 OR you could go back to the 172 [Window05] and copy the changes from there and past them into the 182 [Window05] section. You could also add your 172 modified mini panel to any other plane as long as you keep the Window numbers straight. Having said that, there is a downside. If the panel of the plane that you are adding your 172 modified mini panel to has a different size_mm value in [Window00] section, your mini panel gauges will be there but will have to be resized.