Rudder Question

T

thedude247

Guest
Hey Guys

So I'm out flying my RealAir Spitfire in FS9, and both on my take-off and landing the plane likes to move the the left quite a bit. now this is probably the natural torque of the engine on the aircraft, but I look outside on the rudder itself, and I notice that the rudder trim is way out to the left, but the rudder trim nob inside the cockpit reads 0.0 Degrees.

Anyone care to comment.:kilroy:
 
Anti-Balance Tab

thedude247 said:
Hey Guys

So I'm out flying my RealAir Spitfire in FS9, and both on my take-off and landing the plane likes to move the the left quite a bit. now this is probably the natural torque of the engine on the aircraft, but I look outside on the rudder itself, and I notice that the rudder trim is way out to the left, but the rudder trim nob inside the cockpit reads 0.0 Degrees.

Anyone care to comment.:kilroy:
Click to expand...

To answer your question, later versions of the MKXIV & XVIII were fitted with a broad chord rudder which included an anti-balance tab/trim tab replacing the conventional trim tab fitted to the narrow chord rudder of the PRXIX and early MKXIV's/XVIII's.

The idea was to help with the loss of directional stability on those aircraft that were fitted with the cut back rear fuselage. From what I understand, the anti-balance tab provided a force to oppose the pilots rudder inputs.

The RA Spit shouldn't actually have this arrangement though, as it (correctly) models the narrow chord rudder fitted to high back MKXIV's. (Btw, I don't think the tab is actually animated).

One of today's airworthy high back MKXIV's, SM832 is actually fitted with the broad chord rudder. (See images below for comparison with the narrow chord rudder of RN201) and it would seem this is possibly how the confusion occured with the RA model.

Actually, there were some very nice close up pictures of the anti-balance tab arrangement fitted to Jim Beasley's MKXVII posted on the WIX forums a while back which I was going to link, but it seems the forum is down at the moment!

I'll try again later.

[EDIT] WIX seems to be working now, so here's the link to the pictures of the anti-balance/trim tab (scroll down a bit) and also a brief description in the captions of how it works.

http://warbirdinformationexchange.o...hp?t=21830&postdays=0&postorder=asc&start=210

Cheers

Paul
 
thedude247 said:
the plane likes to move the the left quite a bit. now this is probably the natural torque of the engine on the aircraft
Click to expand...

FYI, the Griffon turned the opposite way to the Merlin (prop rotates to the left when viewed from the cockpit) and therefore the aircraft should pull to the right on take off, and not the left as with the Merlin.

Cheers

Paul
 
Oh well, no worries. I guess I'll just have to learn to fly it as is, it just makes it more challenging thats all.:icon_lol:
 
As a gmax modeler, I can say that when the rudder trim tab is animated, its frame 0 position is to the left, frame 50 at center, and frame 100 at right.

If the correct trim tab name is used and is FS recognized, the trim tab should be centered. If not, the trim tab will show hard left as in your picture.

Also, the trim knob in the VC uses a different name tag and is the one the affects the flight model and handling.

The visual model trim tab (spot view) has little relationship beyond the visual presentation, so it can be animated or not, correctly or incorrectly and have no bearing on anything except visual appearance.

The fact that is is at a hard left position says an attempt was made to animate it. If the name is unrecognized by FS2004, then you have the result.

Also, if you are flying in FS2002, you will have the same result as the name tags changed or were not supported in that sim.
 
I don't have the Real Air Spit, but fly the AH Spit XIX a lot. I've found it's best to ease into the power on take offs to prevent excessive torque pull to the side.
 
Willy said:
I don't have the Real Air Spit, but fly the AH Spit XIX a lot. I've found it's best to ease into the power on take offs to prevent excessive torque pull to the side.
Click to expand...

Even on twins. The RW pilot of the Howard 500 (twin R-2800's) takes 12 seconds to go from standstill to (near) full throttle on takeoff.

If you ease into it, advancing at a slow steady pace, you will find the aircraft and engine will love you much better.
:)
 
but I look outside on the rudder itself, and I notice that the rudder trim is way out to the left, but the rudder trim nob inside the cockpit reads 0.0 Degrees.
Click to expand...

Apologies if my original post was on the long side and not clear (I could have explained it better), but I think you'll find that the answer to thedude247's question is in there somewhere! ;)

As I said before, RA modelled by mistake the anti-balance/trim tab combo fitted on the Broad Chord rudder instead of the conventional single tab that moves either left or right on the Narrow Chord rudder. (Check the pictures I posted above to see the two types of rudders and tabs, and alsothe link to the pics I posted on WIX forum for close up pictures and an explanation of how the Anti-Balance/Trim Tab works).

So, what you are seeing on the external model is actually the displaced Anti-Balance tab, and not any trim tab deflection. I just checked the RA FS2004 XIV, and indeed they chose not to animate it so it will always be in the same positon (neutral) regardless of where the cockpit trim wheel is or rudder postion is (Anti-Balance Tab).

Btw, interesting information Milton on how the key frame animations of trim tabs work.

Cheers

Paul
 
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