Aces High Bulletin Board
Help and Support Forums => Help and Training => Topic started by: CurtissP-6EHawk on January 02, 2003, 04:08:29 AM
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I was reading HTC's explination on elevator control at Trim (http://www.hitechcreations.com/ahhelp/ctrim.html)
I wanted to say something about that and you can correct me if I am wrong or just add you thoughts.
***EDITED***
Thanks for your thoughts and FACTS.
Ok, thats it, all is understood and now my problem still lies in the excessive stick bounce unrealted to the flight models. I could have asked all this in a different way but I just AINT NO POET!
Thanks dtango
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Input on the elevator via the control column or trim changes the angle of attack of the wing in flight. The changes in AoA that is being referred to is the wing not the horizontal stabilizer. The stalls being mentioned refer to the wing stalling not the tail stalling.
Tango, XO
412th FS Braunco Mustangs
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38 degress AOA, and the plane stalls at around 17 degs AOA.
I have no idea why I read that wrong but I did. Maybe because I was reading it at 3am..hehehe
Ok, that makes whole lot better since.
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you pull back on the stick you still get adverse yaw
However, I dont recall ever noticing this in a real airplane. Adverse yaw while banking or rolling yes, but pitch ? no where even near as in HA FMs. I noticed in the F4F, Yak, and a few others when you pull back on the stick you almost get a full deflection on the ball. I dont see this in real airplanes. But then again, we are talking about WWII fighters! This is where my problem starts with my joystick.
This is where the unplayable nose bounce falls into this topic. I get unplayable nose bounce while flying slow in AH even with auto trim on.
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I'm not a real life pilot so I can't comment from a real life feel perspective.
However from an aerodynamics perspective adverse yaw when you pull back on the stick has to do with the gyroscopic effects of the propellor. Probably why you would expect to see it in AH a/c is because of the power engines we have. Infact we've seen some of the opposite comments from other real pilots on the BBS with the opposite statement which is they expected to see more adverse yaw from gyrscopic effects.
Regarding the nose bounce, yeah not sure why you're seeing that. I read over the other thread but not sure I can add much more to the topic. You might want to try giving HTC a call to see what other suggestions they may have.
Tango, XO
412th FS Braunco Mustangs
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I am probably embarasing myself here but I am also an A&P as well as a, some 2,000 hour tailwheel pilot. I do certainly agree on the gyroscopic effects of the propellor. This is mainly noticed on take-off when the tail comes up on tailwheel airplanes. However, just flying along straight and level then pulling back on the stick, I dont see the such drastic gyroscopic effects as I do in AH. But than again, I am refering to the smaller, 600hp or so and less, powered airplanes. The largest tailwheel airplanes I have flown is the Yale BT-14, BT-13, and the tailwheel version of the Beachcraft Beach 18. I flew a DC-3 once but never manuevered enough to notice the, straight and level then pulling back on the stick, ball deflection issue.
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Embarrassing yourself? Not at all :). Gyroscopic effect gets more pronounced the larger the prop as well as with greater "force" from the reaction of change in pitch. Greater the force due to the change in pitch (hard pull) the greater the gyroscopic force. I don't have the equations to run the calcs to demonstrate this to show this mathematically but I believe the above reaction is the gyst.
Tango, XO
412th FS Braunco Mustangs
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My moms stepfather told me he watched a P-51 roll inverted and into the ground on take-off because the pilot more than likely used full power. This was a Korean pilot not American. Maybe he was not properly trained or just forgot..ouch!!!
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Now, that's pretty nasty to auger in like that.
Tango, XO
412th FS Braunco Mustangs
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the tail generates lift in opposition to the wing. For stability reasons the c.g. is in front of the center of lift of the wing with the tail balancing out the forces. If the the tail does stall the plane will pitch over. If there is no yaw at the stall generally there should be no spin. Spins usually occur when one side is stalled more than the other. Most planes i have flown dont exhibit the yaw characteristics I see in AH. That might be attributable to the fact that they are easier to sense and correct for when flying the real version.
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Just a wild guess, but I am guesing the real planes you have flown were not high performance fighters designed 60 years ago.
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DAVENRINO
The largest tailwheel airplanes I have flown is the Yale BT-14, BT-13, and the tailwheel version of the Beachcraft Beach 18.
What do you think?
However, as far as design, I have flown many antique airplanes and I asure you many are better built and fly much better than some modern airplanes.
Waco, 1928, 1930s
Travilair, 1928
Fairchild 24, 1938 best flying airplane I ever owned and flew!!
Davis 1930s
Dehav.Tiger Moth 1940s
and the list goes on>>
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Sounds like mostly torque, Hawk. Your 180 doesn't have the high power combined with a really large prop diameter to make the effects as pronounced as with, say, the P-51.
Back when '51's were cheap...at one time you could buy one for around 10 grand...a lot of people killed themselves with torque rolls. It happened when low and slow, say on landing approach. The pilot aborts and tries to go around. He forgets he's in a Mustang and porks the power. That geared V-12 pours a ton of pure torque into the prop and at low speed, he has insuficient aeleron to counter it. In a heartbeat, he's upside down at 200 ft. This seems to have cost us most of the surviving '51's and now we're down to a handfull and they're worth millions.
There used to be a guy named Doug Shultz who flew a Mustang named Crazy Horse out of Nashua, NH. In the early 80's, you could fly dual for an hour with him for around $1,000. He'd literally train you all the way to checking out in it, but of course, no solo in that aircraft. I'll always be sorry I never came up with the money. He later re-named it Double Trouble, I think, and was leasing it out to the Air Force test pilot school so they could broaden their skills. One of his primary agendas was to teach the danger of torque rolls.
My understanding, is that this and many other nasty charictoristics were engineered out in the Bearcat, which of course, we don't fly because it didn't see combat in WW2. Pity....It's the only other plane that might beat your beloved Tempest. :)
Simpelest way to think of all these effects is to remember in most WW2 fighters, the prop is so large in relation to the wing span that it just doesn't compare with civilian aircraft, no matter what the power.
One other thing...In any prop plane that is single engine, or doesn't have counter rotating props like the '38 or the Senica, Just pulling the stick back and going to a higher AOA will give you some yaw due to the descending blade going to a higher AOA in the realitive wind. If you don't center the ball, the stall snaps you into a departure.
Hope this sheds some light.
Swoop
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Ok let me get back on track here. I started this post out on the trim and stall issue. I read it wrong and know understand what HT was explaining.
Then we jumped to stick bounce, nose jump and gyroscopic effects of the propellor. I fully understand this area but I do not have first hand experiance with the Fighters and thier huge paddle blades along with thier muscle horse power.
Your 180 doesn't have the high power
I know that guys, c'mon I dont mean to make myself look that ignorant. Swoop maybe you missed this part, "The largest tailwheel airplanes I have flown is the Yale BT-14, BT-13, and the tailwheel version of the Beachcraft Beach 18." they have a hell of a lot more torque and power than the 180!
You guys are missing the point that I am sure I am not explaining well enough for anyone to understand but maybe dtango.
I know that the bigger fighters have the big paddle blade props and create a reat deal of gyroscopic precession. I just didntb realize it had that great of an effect in level flight at slower airspeeds and as HT explained, pilots dont normally use as much stick throw in a real airplane as we do in this flight sim based on "feal" and is why I never really noticed it.
In HA, the Yak-9U has a great deal of gyroscopic precession, much more than even the P-51. When you close the throttle in level flight and move the stick foward and aft, the ball stays almost centered, this I agree hehehe with based on what little knowlage I have on what I read of the bigger engine, paddle blade equiped aircraft :)
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CurtissP-6EHawk,
I wasn't making light of your flying experience. I have a bit of flying experience, myself. My point was none of the planes you listed are high perf fighters with high wing loading and intentionally designed instability. Yes, intentional. Instability = maneauverability. Your experience is in planes with high-lift wings and low wing loading designed to be stable with docile stall characteristics that beginner pilots can handle. Fighters and acrobatic planes are designed sacrificing stability for maneauverabilty. It is always a compromise cause it is difficult to get both. Some acro pilots fly their planes at the aft edge of the center of gravity envelope to make them less stable (more twitchy). WW2 unstable,high wing loaded planes spin easily when stalled at low speeds combined with P-factor and Torque listed above, especially with abrupt control inputs. You can get the same result at high speed if you cause an accellerated stall. If a wing is stalled it doesn't produce lift regardless of speed. I think you will also agree that the lower wing loaded AH planes such as the Zeke are more stable and less succeptible to nasty spins. I have not flown any real-life warbirds but from what I have read, I think the AH stall/spin model is as close as you can get in a game.
Dave aka DJ229
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No problem DAVENRINO, I just wasnt sure what you ment because you adressed it as a statement not a question. If you go back up a little on one of my other replys I said,
But then again, we are talking about WWII fighters
, although I did not make it clear, I was refering that I unfamilure with them.
As far as the antique airplanes mentioned, that was for the 60 year old design reply you mentioned and not related to the high performance issue at hand.
I have flown some aerobatic airplanes, although I am not an aerobatic pilot by any means, and my memery is unfolding a bit, my how we do forget some things....ok a lot of things and I am only 36!!!
Ok, thats it, all is understood and now my problem still lies in the excessive stick bounce unrealted to the flight models. I could have asked all this in a different way but I just AINT NO POET! :D
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zrex I forgot about your reply. My dad and I discused this years ago with his experiance. I guess the CG and lift was situated somehow where the attitude did not change when the tail stalled, if indeed the tail stalled at all. We really dont know. He wasnt about to try it again to find out :D
DAVENRINO, oh yeah one last thing, I know aerobatic airplanes as well as fighters need to be somewhat unstable in a since so they can perform manuevers. I have a very close friend that owns a full scale Fokker Dr-1. Flying it literaly exhausts him. He offerd to let me fly it...I humbly declined :eek: