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Rudder Trim Tab

R

Reddsky1

Active Member
I have just started my RV-10 tail kit.

I am hoping to find the builder I visited with At Oshkosh, on the last thursday during the airshow. He modified his rudder and added an electric trim tab. I hope he wouldn't mind sharing the plans of the Mod. All the credit goes to him of course.

Any help would be appreciated

Thanks, Reddsky1
Building RV-10
(604PT reserved)
 
I saw an RV-10 rudder trim tab mod at sun 'n fun this year. The builder used a standard servo and had it swinging a piece of trim tab hinge. The servo was mounted inside the rudder. I was able to speak to him. He said it was quite effective, it gave him one ball displacement, either side of center. I don't think the hinge was more than 6-8 inches in length.
 
Jesse Saint also has electric rudder & aileron trim installed and used AeroTrim (both planes). I didn't so an exhaustive search but found the following contact number for AeroTrim: 305-864-3336.

Bob #40105
 
I have electric rudder trim on my 8 and use it quite a bit. I would not recommend this on normal 8's, but for my super 8 where I fly and 150kts with my buds, and 200kts alone, this gets used a lot. I have no details other than I mounted a servo in the rudder, fabricated a trim tab out of aluminum, and made it work.
ruddertrim.jpg
 
rudder trim

I confess. It was me. I just used a MAC trim servo, the one with the most travel. I riveted a piece of the 357 piano hinge, 11" in length to the rudder. It does give 1 ball width left and right of the box during cruise. I can trim the airplane completely hands off. The switch and indicator are on the center console just ahead of the fuel switch. I'll take some pictures today and either post them here if I can figure it out, or send them to Tim (myrv10.com). He may already have some of them up.
I think it is the best mod I ever made to the airplane. I initially used one of the fixed pieces, but it was really only good for one speed and power setting. I got tired of having to ride the pedals during long descents from the middle teens. So, when I inadvertentaly pushed the airplane out of the hangar before the door was completely open..... well you get the picture. :( It was new rudder time, and I just went ahead and added the electric trim. The cable is routed out the bottom of the VS just below the lower rudder attach bracket, across through the lower rudder fairing, and then up through the rudder.

Vic
 
Rudder trim

I am also going to put rudder trim on my 10. Vic, I saw your mod. at Sun-N-Fun. It looked fantastic. Looking forward to seeing the pics, sounds like the way to do it. BTW, has anyone considred some sort of spring bias manual rudder trim?
Thane
 
Vic,

Sorry it has taken so long to reply.


Where do you mount the servo and route the cable?
Did you use the same cable as the H.S. Trim Cable?
If you could post a rough drawing that would be helpful.
 
Here's what I wrote in the earlier email:

I think it is the best mod I ever made to the airplane. I initially used one of the fixed pieces, but it was really only good for one speed and power setting. I got tired of having to ride the pedals during long descents from the middle teens. So, when I inadvertentaly pushed the airplane out of the hangar before the door was completely open..... well you get the picture. It was new rudder time, and I just went ahead and added the electric trim. The cable is routed out the bottom of the VS just below the lower rudder attach bracket, across through the lower rudder fairing, and then up through the rudder.

I did use the normal trim cable, available from Spruce. Someone else mentioned it might be cheaper to run 2 runs of shielded cable, one 2 conductor and one 3 conductor. The servo is actually mounted to the cover plate. You can see the pictures on Tim Olsens web site.

vic
 
Yes, they are stainless, and I think it was a place in NJ. Probably Fasteners, Inc or something simple like that if I remember correctly. If you do a search in the forums or on the matronics list for them you should be able to find the address. If not, I will be home this week end and will look up the address.
Vic
 
Vic--------if you were doing it again, would you consider cutting into the rudder and installing a more "traditional" style tab?? I think it would look better, but more work, also the thin skin might be a problem that needs to be addressed.

It looks like the size of the tab (hinge) you used is a bit small----do you feel it is enough, or would you like more authority??

Thanks,
Mike
 
Hi Mike. I'm actaully perfectly satisfied with the trim after about 300 hours. It has enough authority to move the ball one full width left and right of center in cruise flight. I'm sure it could be made prettier, but it is functional, simple, and easily replaceable if damaged.

Mel is right--- the company is microfasteners. Thanks, Mel.

Vic
 
Rudder trim tab

Link, for the record I am not an engineer, aeronautical or otherwise. What I have done is make this modification and throughly test it to the best of my ability, under all flight conditions as would be expected during normal operations, up to an including test flights for flutter as per our phase one testing. I now have over 300 hours on it. That doesn't mean it would work the same on every other airplane, as balance could be different, due to paint, constructions technique, counterbalance, etc. Everyone using this mod needs to test it appropriately. I am not aware that the team at Van's has any problem with this modification, but I won't and can't speak for them.
There's been a lot of improvments in the Van's series over the years as a result of builder-incorporated improvements.
As for the service bulleting on the tail, anything could have caused that spar to crack on Van's RV-10, including something as simple as not deburring the hole and missetting the rivet. I kow I riveted mine on differently, having the shop head on the metal bracket, vs. the other way, and I beleive it was stronger. Yes, I did the SB anyway. :)

No problem with questioning. That's what this forum is all about.

Vic
 
wv4i said:
Not trying to just be one, but has anyone considered what effect the weight(s) and location(s) of this modification may have on structural integrity and aerodynamics of the rudder, etc.??? Flutter? Rudder authority avail/new limits? Need to change counterbalance weight? Effect on aerodynamic center of rudder with mod? Skin, rudder skeleton integrity, etc.? Modify flight envelope limitations? Need to go back into Phase I flight test? Temporary operating limits and flight test area? Etc.? Note that Van's already has a SB out re addition of a hinge doubler to Vertical Stab rear spar due crack being found near upper rudder hinge area. Sorry to put water on the fire.

Link McGarity
#40622 HS assy
RV6/N42GF/flying
Click to expand...
Link,

I think if the addition of a simple trim tab to the rudder, causes such questions and concerns, then you should NOT consider building an EXPERIMENTAL RV-10 and buy a Piper/Cessna/Cirrus and forget this EXPERIMENTAL stuff.
 
Control Surface Mods....

William, Perhaps I went a little far in a list of possible concerns, but I also get concerned as to who might be reading this thread, experience level, knowledge of aerodynamics, etc. Flutter characteristics are a valid concern when making a control surface mod. There are other factors to consider as well. Van's has an excellent link on their site to what I believe is a past RvAtor article that discusses flutter as a determining factor of Vne in Van's aircraft. The article discusses this subject in the context of why operating a turbo charged engine in an RV could lead to trouble. But, re this thread, as long as one understands that flutter point is affected by hinged weight, location of weight vs hinge, etc., then the decision to mod a control surface goes from there as Vic describes.

As far as switching to spam cans, sorry, but that's the day job, big ones now, and since 1979 actually. You were not serious were you? Hi......

Link McGarity
RV6/N42GF/flying/3x OSH/2 X LAL/3.5 yrs
RV10/#40622/elevators
 
Piano Hinge and control cable

Vic,

Could you let me know the size of the piano hinge (width) and where you purchased it? Could you also provide some information on the control cable?

Thanks
Dave Syvertson
 
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