Aces High Bulletin Board

General Forums => Aircraft and Vehicles => Topic started by: Duckwing6 on December 14, 1999, 04:15:00 AM

Title: Adverse Yaw
Post by: Duckwing6 on December 14, 1999, 04:15:00 AM
Hyas!
maybe just my oppinion but from my flying experience no powered airplane (especially HIGH powered airplane) has such a strong adverse yaw (e.g. if you roll right the nose swings left and vice versaw) than the AH planes (pretty much all of them).

They feel more like gliders in that respect.. I see the need of alot of rudder for turque and P effects countering on these planes but roll yaw coupling needs to be worked on.

SC-Duckwing6
Title: Adverse Yaw
Post by: funked on December 17, 1999, 02:28:00 PM
I remember reading that the F4U had a significant adverse yaw.
Title: Adverse Yaw
Post by: Duckwing6 on December 20, 1999, 09:20:00 AM
well as i said maybe Torque, Slipstream, Gyroscopic effects and P-factor when you are slow and/or have a high AOA but not that strong adverse yaw when you make an aileron input during cruise... I mean these things have short and straight wings both not really prone to Dutch roll and adverse yaw phenomena...



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Title: Adverse Yaw
Post by: funked on December 20, 1999, 11:32:00 AM
Yes, but they don't have much vertical stab area in most cases.
Title: Adverse Yaw
Post by: CombatWombat on December 20, 1999, 01:56:00 PM
Despite the small vertical tail adverse yaw still shouldn't be a problem.  It's caused by one aileron creating more drag than the other for a moment (or so I believe).  From what I've heard this was only a problem in a few aircraft, most notably the P38L.  

Despite it's large wingspan and wideset ailerons, the standard controls couldnt exert enough force to expose the ailerons into the airflow.  Hence, no (or little) adverse yaw.  The L model with it's hydraulic controls was more prone to yawing.  

As for normal shorter-winged singles, AH seems to over-do the yaw.  In my expierience this is the cause of most of my "nose bouncing".  Once at speed the side of the fusalauge should offer plenty of stability.  
Title: Adverse Yaw
Post by: Duckwing6 on December 20, 1999, 04:33:00 PM
true wombat.. the longer the wingspan the more adverse yaw.
Also Rudder input at high speed should be way more damped.. unless the plane had hydraulic controls the pedals must have been VERY stiff at higher speeds .. given the big maximum deflection angle.
Title: Adverse Yaw
Post by: -lynx- on December 21, 1999, 02:30:00 AM
Well all planes suffer from adverse yaw - it's caused by the same thing that keeps them in the air   (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif). The pressure on the underside of the wing is higher than the pressure on the upper side (hence lift  (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)). Therefore an aileron deflected down would create more drag as the pressure on it's surface is higher than that on the other side causing the whole thing.

I'd have thought that later war plane with all hydraulics and stuff should be free of adverse yaw effects? Certainly it shouldn't be THAT noticeable when 7,000-10,000lbs is moving at 300+mph. Same goes for the dreaded nose bounce...

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-lynx-
13 Sqn RAF

[This message has been edited by -lynx- (edited 12-21-1999).]
Title: Adverse Yaw
Post by: funked on December 21, 1999, 06:11:00 AM
Wombat:  America's Hundred Thousand has handling qualities reports for the US fighters, and there are plenty of mentions of adverse yaw and directional stability problems.
Title: Adverse Yaw
Post by: CombatWombat on December 21, 1999, 04:35:00 PM
At what airspeed?  The thought of 10,000 lbs moving at 350mph and bobbing back and forth kinda boggles the mind.


>Wombat: America's Hundred Thousand has handling qualities reports for the US fighters, and there are plenty of >mentions of adverse yaw and directional stability problems.
Title: Adverse Yaw
Post by: funked on December 21, 1999, 08:15:00 PM
I don't remember the airspeed, but I agree that at 350 mph things should be pretty stable.
Title: Adverse Yaw
Post by: Duckwing6 on December 22, 1999, 04:36:00 AM
how about asking -ZOLL- on the F4U he has the firsthand experience on moving an F4U around at 350mph ... i doubt that he's using the rudder too much while manouvering (unless you do a WIDE speed range in your manouvers)

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Title: Adverse Yaw
Post by: flakbait on December 22, 1999, 10:46:00 AM
No kidding about that adverse yaw. I was driving a 190 around today and every time I moved the ailerons I would slide around like I was on ice. It needs to get fixed.

Flakbait
Admin, Delta 6's Flight School
Title: Adverse Yaw
Post by: BBGunn on December 27, 1999, 04:06:00 PM
Most all of the basic flight manuals I have come across state plainly that if you roll right you have to use right rudder and if you roll left you have to use left rudder to compensate for aileron induced yaw.  You really cannot just roll the plane and expect a smooth turn.  Even in something as docile as a Cessna 172 you have to use some rudder or the nose will go high on you.  
Title: Adverse Yaw
Post by: Duckwing6 on December 28, 1999, 01:25:00 AM
well i've my share of flying experience in the 172 . and other planes .. but belive me they WILL turn smoothly when you just use the yoke (to make a REALLY nice coordinated turn you'll hardly have too look at the rudde pedals) .. That's why all the Cessna jokeys forget what the rudder's for  (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
i'm flying gliders a lot too and THERE you need a LOT of rudder but as said that's 17m (56 ft) wingspan to act as a lever for the drag created by the down alieron...
Title: Adverse Yaw
Post by: Swoosh on December 28, 1999, 07:30:00 PM
Its easy to tell the guys who don't get the "bungee bounce" effect.  
Title: Adverse Yaw
Post by: lemur on January 02, 2000, 02:38:00 AM
As far as I can tell, P-factor isn't a factor in this game. Not that I mind, since I'm more concerned with higher speed handling ("Hi, I'm Lemur. And I'm a an e-fighter". "HI LEMUR")

I'm hoping that as the flight model gets tweeked further we do get to see more of the individual quirks of the planes appear.

While on paper the p-47 didn't look all that great, the men who flew it consistantly praised it as a very stable platform. Whereas folks dammed the Yak-9 as a very 'bouncy' gun platform. Be nice if these distictions made it into the model.

~Lemur