Paul Eastham

Paul Eastham

Well Known Member
Builders who have gone before me:

I am in that last chapter of the manual where Van's finally decides to disclose the min/max acceptable travel for all the control surfaces. Sadly, my ailerons travel about 1 to 1.5 degrees past the max allowed, and Van's says that it is "probably worth" correcting this (without saying why). I have also heard some stories about bellcranks going "over center" and locking up -- perhaps due to excess travel? I don't know.

At any rate, fixing this little problem does not look easy. Looks like I'll have to detach control rods and remove all ailerons and flaps, drill out the little aileron travel stops, and put in larger ones. I am wondering if anyone has come up with a better way, or determined that such modification is not necessary. A little part of me has considered epoxying on a tiny doubler to the stop or something like that, since we're probably only talking about 1/32" here.

Thanks,
Paul
 
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I don't remember who it was, but somebody on here had what looked like a much simpler aileron stop design. It was essentially a small delrin sleeve slipped over the bolt that connects the pushrod to the aileron. It's worth looking for.
 
No Pics

I was doing my walk-around today and when I came to the Aileron with Mickey's brilliant Aileron Stop that I fittied, I hesitated and thought of taking a pic of it installed.............. but didn't.

Regret it now.

Does anyone want a pic of it installed............ so they can see how it fits?

Pete.
 
Paul,

Head down to Lowes or another hardware store with a good selection of parts. Pick up a couple of nylon bushings. I used 1/2" diameter, but am finding that may be a bit small.
 
P1000046.JPG


found on my friends homepage, Berni and Alex http://flyvans.com

I have made the Delrin-Bushing for them.

The Delrin sits with a light press-fit on the standart aluminum spacer.

regards,

Dominik
RV-7A, very slow build
 
Paul Eastham said:
...........fixing this little problem does not look easy. Looks like I'll have to detach control rods and remove all ailerons and flaps, drill out the little aileron travel stops, and put in larger ones. I am wondering if anyone has come up with a better way, or determined that such modification is not necessary......Thanks, Paul
Click to expand...
Paul,
Mickey's solution is about as elegant as you can get. Inspired by his creativity, I ordered 1 foot of Delrin rod from Spruce but the 1/2" diameter was woefully inappropriate. Just for grins, I stacked some AN970-3 area washers and as it turns out, is a much better fit....at least I know what diameter rod to order next time.
errata05910tb2.jpg

Alternatively, using these area washers, a builder "could" radius out just enough material from the aileron bracket so that the washers meet the bracket at the maximum design limit of aileron travel. But that is a little like the tail wagging the dog. Better to go the Delrin route.
 
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In case anyone comes across this thread in the archives...I am not sure the "spacer stop" method is a good one for RV-9's. A very large spacer is needed. 1 1/8" still left me with one degree too much down aileron each side...and you are left with this big thing sticking out into the slipstream. You can't go any bigger than 1 1/8" due to the shape of the attach bracket.

I started out trying to clear up a 2-degree excess with my riveted-on stop, now I'm down to 1 degree. I suspect Van's will still want me to correct this problem :(

20070321_IMG_4545.JPG

20070321_IMG_4546.JPG
 
Paul,

Sense the spacer doesn't need to rotate it doesn't need to be round. Why not give it a couple of flat sides. One to fit against the bracket and one so that it won't stick up into the slipstream. Don't know if this will work and still function as a stop.

Kent
 
Other Experiences?

I've used the delrin approach and used the 1/2" diameter that was suggested. My wings are not installed, but the 1/2" gave me the exact UP deflection that VAN's recommends after using the VAN's provided bellcrank jig to set my aileron pushrod length. I can't check the DOWN deflection, since this is determined by the UP deflection on the opposite aileron.

This thread, however, is getting me nervous. I'd like to know the experience of the rest of you who have used the delrin stop and what diameter you used. Particularly interested in those that have used this and mounted their wings so both UP and DOWN deflection can be measured.
 
I might have given Paul some bad advice (sorry, if so), but Mike Schipper's flying 9A is using the delrin that is exactly the diameter of the large washer in that assembly. He indicated to me at Oshkosh that it gave him perfect travel. Of course, I didn't measure his up/down deflection myself but I did see the size of the delrin with my own eyes. Not sure why the discrepency between Paul's experience and Mike's experience.
 
Totally off-topic for a moment:

Paul, it's great to see Torque Stripe being used as it should be. I suspect an awful lot of "Ooops, how the heck did I miss that?" moments during airworthiness inspections would be eliminated by simply using that $5 tube each time something critical was torqued.

Kudos to you!


OK, enough hijacking. Back to the regularly-scheduled thread currently in progress...
 
Thanks Ken.

Here is the rough shape I arrived at today: The lower right area is the part that will contact the aileron mount (about 21/32" from the center of the hole). The flat area and tab on the left are meant to keep the thing from rotating out of position. The top part has a reduced radius to match the aileron bracket and keep it out of the airstream.

20070323_IMG_4548.JPG


After making a second copy and cleaning them up, I put these on the airplane and they seem to work! The angle is now within limits. Thanks to everyone who contributed to this thread (and indirectly to my airplane :)
 
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