Subject: PYRO: P-47 lateral Stability question

Newsgroups: warbirds.general

Pyro, have you ever noticed that the 47 needs lots of rudder left and right even for some pretty average speeds? For example trim at 200ias. Build up speed for an immelman and you'll have to hold left rudder as speed picks up, and of course right rudder as it slows down.

Now all the ac in WB and in real life need left rudder as you pick up speed, but the JUG needs it more than any other. Is this simply because we have the jug without the extra fuselage material to aid lateral stability 47D-30 or is it a glitz in the code?

Worr, out

Prov 18:12

Subject: Re: PYRO: P-47 lateral Stability question

Newsgroups: warbirds.general

From: Wells Sullivan

The reason trim changes is because of stability. The P-47 is in the same ballpark as the 109,190 and Spit IX for lateral stability. The P-51 is less and the F4u is much more (10-20%). The aircraft with it's CLA (Center of Lateral Area) the furthest behind the CG will require the most trim. Try the F4u-4 out and see how much rudder trim you need to center the ball. I needed 9 clicks compared to the P-47's 5 clicks (change from 200-300 mph). This is because the F4u is more stable directionally...

Subject: Re: PYRO: P-47 lateral Stability question

From: Andrew 'dekker' Smith

Newsgroups: warbirds.general

Hey Wells?

Do you have ANY gripes with the plane flight models in WB? =)

I enjoy reading your posts, but with you being so informed,and the quality of your postings, I am curious if thereis anything that you, in particular, have noticed as out of place in any particular plane in WB that you might like to share?

Other than the Yak engines turning the wrong way? =)

Dekker

CO 401 RCAF Rams

Subject: Re: PYRO: P-47 lateral Stability question

From: "Worr"

Newsgroups: warbirds.general

Which Jug do we have then? The one before or after the lateral stability fix?

P47D-30 added the cross piece before the vertical stab to help with this.

BTW...Goebels said to me he had a 51D that didn't have this little cross section either and he was all over the rudder trim in flight. That guy was a wealth of information....especially for detail.

Worr, out

Subject: Re: PYRO: P-47 lateral Stability question

From: Wells Sullivan

Newsgroups: warbirds.general

I think I know what ur sayin, and being too stable and unstable are very similar. I mean, if the plane is very stable, the slightest power or speed change will cause the plane to climb or dive rapidly (and roll and yaw), correct? But it's trimmable and predictable. A neutrally stable or unstable plane sorta wants to go wherever, whenever...and the controls and trims are too sensitive making the plane almost non-trimmable and difficult to fly with the pilot having to 'fly' it constantly (kinda like what fly-by-wire does nowadays). I don't think we have the model with the extension of the fin (look at the 3d model?). Most directional instability was measured at high angles of attack with gear and/or flaps down. Perhaps WB hasn't got quite as sophisticated a model to be able to accurately predict downwash angles and turbulent flow over the tail surfaces?

Subject: Re: PYRO: P-47 lateral Stability question

From: villepeh

Newsgroups: warbirds.general

> Most directional instability was measured at high angles of attack with gear and/or flaps down.

While we're at it, does WB do high AOA/rudder/roll correctly? In 109 for example, if I am high AOA and put rudder the thing just quits rolling almost completely. With ailerons only it will roll much faster. I thought the opposite should be true?

Well possible cause could be that I simply put too much rudder.

\0

Subject: Re: PYRO: P-47 lateral Stability question

From: Wells Sullivan

Newsgroups: warbirds.general

I'm not exactly sure what you're getting at here. The effect of rudder on roll has to do with the yaw angle and the dihedral angle. The planes in WB can yaw 15 degrees and most of them have about 5 degrees of dihedral. The effect of rudder on roll is that maximum rudder should roll the plane about 1/2 as fast as ailerons and that roll rate can be increased by using rudder together with ailerons. However, at high angles of attack, very near stalling, the effects of both rudder and ailerons will be cut in half because a wing can't lift any more past the maximum angle of attack.