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  #1  
Old 02-22-2023, 07:45 PM
Pman Pman is offline
 
Join Date: Nov 2013
Location: Geneva, Illinois
Posts: 58
Default RV8 Manual Rudder Trim

Hi All,

For those who have installed an adjustable "manual rudder trim" feature on their flying RV8, can you please share how you did it? Also, it would be helpful to know where you purchased the needed hardware and part numbers?

I'm familiar with how to make and install the many different options of a fixed rudder trim tab, however, I'm interested in a rudder trim system that will provide me control of multiple speed/power ranges.

Thank you!

Mike Perillo

Last edited by Pman : 02-22-2023 at 08:19 PM.
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  #2  
Old 02-23-2023, 07:46 PM
Wing nut Wing nut is offline
 
Join Date: May 2017
Location: Glyndon, MN
Posts: 9
Default RV8 Manual Rudder Trim

I too have been pondering this type of manual rudder trim. Any ideas would be welcome.
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Brett N
RV 8 flying since 2010
XP 360 with AFP FI
WW 200 prop
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  #3  
Old 02-23-2023, 07:56 PM
oaklandaviator oaklandaviator is offline
 
Join Date: Dec 2014
Location: Las Vegas, NV
Posts: 165
Default Cable and spring

A friendís 8 had a knurled knob on the right side that turned a threaded Rod attached to a cable to a pulley on the back of the lower firewall that then attached to the back of the right rudder pedal. He said it didnít do much but it looked functional to me. Might could put a stronger spring on.
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  #4  
Old 02-23-2023, 08:38 PM
moespeeds moespeeds is offline
 
Join Date: Apr 2021
Location: Cherry Hill, NJ
Posts: 239
Default

Here you go, works great: https://vansairforce.net/community/s...d.php?t=209124
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Moe Colontonio
Cherry Hill, NJ
RV-8 N495T

Last edited by moespeeds : 02-24-2023 at 10:35 PM.
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  #5  
Old 02-23-2023, 08:51 PM
andoman andoman is offline
 
Join Date: Jul 2006
Location: Payson, AZ
Posts: 141
Default Servo to Rudder Cable?

The pix shows my tie-in to the rudder cable for the rear seat rudder peddles on my -4.
Iíve been thinking of mounting a trim servo and attaching a spring then a cable directly to the right rudder cable. Like I did for the peddles. Perhaps mounting it just aft of the baggage compartment.
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"The plane won't build itself..." RV-7A N7.62MM sold
-RV4 purchased. Extensive refurbishment complete. ďTakes off by itís self, flys hands off, lands by itís self...Ē
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  #6  
Old 02-24-2023, 05:40 PM
Wing nut Wing nut is offline
 
Join Date: May 2017
Location: Glyndon, MN
Posts: 9
Default Thanks

Quote:
Originally Posted by moespeeds View Post
Thanks for the input. Some one like Anti Splat should make and sell these!
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Brett N
RV 8 flying since 2010
XP 360 with AFP FI
WW 200 prop
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  #7  
Old 02-24-2023, 06:10 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 3,462
Default

I was thinking of a pair of springs from the top of the rudder pedals pulling toward the firewall, with a bias lever, similar to the way the aileron trim springs work.

For me, there isn't room up there to do that, because I have the pedals all the way forward as far as they can be. But an added benefit would be keeping the rudder cables taught all the time.
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Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet" Flying since Sept. 2009
Hobbs 725
also
1/4 share in 1959 C-182B (tow plane)
LS6-15/18W sailplane SOLD
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  #8  
Old 02-25-2023, 07:44 AM
Pman Pman is offline
 
Join Date: Nov 2013
Location: Geneva, Illinois
Posts: 58
Default

Quote:
Originally Posted by moespeeds View Post

Moe,
I see the spring is from McMaster, however, what about the other pieces of hardware? Where did you get the other pieces of hardware, of did you make them?

Thanks everyone for your replies!

Mike
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  #9  
Old 02-25-2023, 10:37 AM
moespeeds moespeeds is offline
 
Join Date: Apr 2021
Location: Cherry Hill, NJ
Posts: 239
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Quote:
Originally Posted by Pman View Post
Moe,
I see the spring is from McMaster, however, what about the other pieces of hardware? Where did you get the other pieces of hardware, of did you make them?

Thanks everyone for your replies!

Mike
I made them
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Moe Colontonio
Cherry Hill, NJ
RV-8 N495T
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  #10  
Old 02-25-2023, 08:31 PM
Joe Joe is offline
 
Join Date: Oct 2005
Location: Independence, OR
Posts: 446
Default Linear actuator and spring on the right rudder cable

I fabricated a "bridle" (at least that's what I think it's called) to capture the right rudder cable forward of where it goes into the spar. Using the TLAR method (that looks about right) I selected a spring from my collection and used an Actuonix 12V linear actuator left over from another project.

The theory was that the spring would apply more or less (down to zero) right rudder pressure, which is what my RV-8A requires at various speeds. This conveniently allowed me to mount the actuator on the rear wall of the aft baggage compartment. I certainly don't have any room between the rudder pedals and the firewall for any kind of a rudder trim system.

It worked fairly well in the 2-3 test flights I flew. And when parked on the ramp I ran full right rudder trim so the rudder no longer banged on the stops.

But at low speed/high power it needed more right rudder, i.e. an actuator with more throw (100 mm vs. the 50mm I installed). I didn't feel it was worth the $90 it would have cost so so I haven't bought it (yet) and removed the components, at least for now.
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RV-8A
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