GAS Stearman (FSX) and elevator trim

[MarkH]

I'll start with the question: can the operation of the elevator trim be changed by tweaking something in the aircraft.cfg? (Or in some equally simple way?)

This is a lovely model that I've hardly flown this because it always seemed to fly unreasonably fast and was hard to take off and land. Having dug it out again I realise this is because the elevator trim seems to be extremely nose-down by default. In other words, when the trim lever is set to neutral (and the tab appears neutral), the aircraft flies hands-off at 110mph (PT-17) or 120mph (N2S-3), requiring full power to even approach straight and level flight. With full nose-up trim (trim tab deflected steeply downward) the PT-17 flies hands-off at about 65mph, and the N2S-3 at 75mph.

This doesn't seem right, because it means I need full nose-up trim (a lot of turns of the wheel!) for the approach and takeoff. Has anyone else had this experience, or is something wrong for me?

[jmig]

Mark, I have flown each of the above models and have NOT experienced the problems you mention. Quite the opposite, I found the Stearman models easy to fly. If I recall correctly, I am airborne by 60 mph or so.

There is a key combination to set trim to takeoff. I don't recall what it is because I have it programmed to a button, but use it to make sure your trim is correct before takeoff. Shortly after full power the tail should come off the ground and the airplane will basically fly itself off the ground.

You might try deleting and reinstalling the airplane. It is possible you have a glitch in the installation? Good luck. That is a fun and historic airplane.

[MarkH]

You might try deleting and reinstalling the airplane. It is possible you have a glitch in the installation? Good luck.

Well I tried that, with no difference. I also installed it on my desktop PC, with the same results (this includes whether I install the patch or not) :(



make sure your trim is correct before takeoff. Shortly after full power the tail should come off the ground and the airplane will basically fly itself off the ground.


Approximately where does your trim lever sit for takeoff? The nose comes up at 50mph, but it doesn't take off unless I pull hard, even with the trim lever all the way back.

It would be very helpful if you and I could compare the original downloaded file to see if we have different versions. I purchased mine from Flight1, and I have these two files (first is the Flight1 download package, second is the unwrapped installation EXE file):

GASB75X.exe / size 61,862,394 bytes / modified 30 ‎December ‎2009, ‏‎18:42:41 / file version 3.0.0.3
Boeing_75_FSX.2.0.exe / size 60,705,526 bytes / modified 30 ‎December ‎2009, ‏‎18:54:40 / file version 2.0.0.29

Thanks.

[jmig]

Well I tried that, with no difference. I also installed it on my desktop PC, with the same results (this includes whether I install the patch or not) :(



Approximately where does your trim lever sit for takeoff? The nose comes up at 50mph, but it doesn't take off unless I pull hard, even with the trim lever all the way back.

It would be very helpful if you and I could compare the original downloaded file to see if we have different versions. I purchased mine from Flight1, and I have these two files (first is the Flight1 download package, second is the unwrapped installation EXE file):

GASB75X.exe / size 61,862,394 bytes / modified 30 ‎December ‎2009, ‏‎18:42:41 / file version 3.0.0.3
Boeing_75_FSX.2.0.exe / size 60,705,526 bytes / modified 30 ‎December ‎2009, ‏‎18:54:40 / file version 2.0.0.29

Thanks.

Mark, I purchased mine directly from Golden Age Simulation. It is called B75_FSX and shows to be 57,849,297 bytes. I guess I have the original files.

[MarkH]

Oh dear, I wonder if mine is just behaving normally after all. Having received a different installer from GAS, things are exactly the same. But comparing the required takeoff trim with others, it seems this aircraft does need aggressive trim (lever almost horizontal) for takeoff. With trim in this position (6 degrees on the tool-tip), the PT-17 takes off at 75mph. I was wrong in saying I need to pull it off the ground, although I was doing most of my tests with the Navy one, which needs even more trim.

I think I will try mapping the trim to a lever, so it operates more like the real thing.

[jmig]

Oh dear, I wonder if mine is just behaving normally after all. Having received a different installer from GAS, things are exactly the same. But comparing the required takeoff trim with others, it seems this aircraft does need aggressive trim (lever almost horizontal) for takeoff. With trim in this position (6 degrees on the tool-tip), the PT-17 takes off at 75mph. I was wrong in saying I need to pull it off the ground, although I was doing most of my tests with the Navy one, which needs even more trim.

I think I will try mapping the trim to a lever, so it operates more like the real thing.

Mark, I just finished flying both the PT-17 and the Navy model. You are correct in your observations. With the trim lever at the 12:00 position, the tailwheel came off at 60 mph but I had to give a good deal of back pressure to get airborne.

I then set the trim lever to the 10:00 position, pointing at the left hand top screw, and only light back pressure was needed to lift off.

I have the coolie hat button set for trim on my joystick. Using it I was able to trim to a 80 mph climb. The lever was then around the 8:00 position. I continued to add trim until the lever was at 6:00 and the airplane started to stall.

I don't know if the animation is wrong or if the lever is supposed to move like that? I have never flown a Stearman in real life. However, I am fine with it as it is, since I use the trim button anyway. If you think it should be different you might go the the Golden Age Simulations site and ask them about the trim.

[MarkH]

I don't know if the animation is wrong or if the lever is supposed to move like that? I have never flown a Stearman in real life. However, I am fine with it as it is, since I use the trim button anyway. If you think it should be different you might go the the Golden Age Simulations site and ask them about the trim.
I haven't flown a real one either (chance would be a fine thing) but the lever movement looks more or less or less correct, although it does seem to drop off the end of the scale! I have plenty of analogue levers spare on my setup, so I will map the trim to one of these, which will make it work just like the actual lever.