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manual aileron trim

hydroguy2

hydroguy2

Well Known Member
I decided I didn't like the lever Vans supplied, so today I tried to buy some AL bar stock. I went to a old time machineshop we use for work and ask if he had any for sale or could I rummage his scrap bins. He said we have no scrap pile, it's all good stuff. I thought "great what's this going to cost?" He was scribbling notes while I described what I needed. Come On! I just need a 6"x2"dia AL bar stock..or something close I'll make it work!!!!!!! Then he said what's it for? Ok, I'm building a airplane, an RV-7. He looked up from his notepad and leaned on the counter and I thought he was going to cry when he said, I've always wanted to build an RV-8. "come on back let's get you some stuff." I spent 30 minutes talking while he loaded me up with various AL sizes. I kept saying that's enough(I only needed a $5 chunk of scrap). Back at the counter, His wife ask about making out an invoice. He said "it's taken care off, he owes me a ride". She said "all that?" and walked away. I tried to pay him, but no go...Ride it is!

Anyway, 3 hours later, here's a first draft of the knob I fabricated today.

RV7315.jpg
 
yakdriver said:
So Brian, you did make another one for me didn't you? Don
Click to expand...

Oh, I suppose I could be talked into it....I got enough material for a few dozen.:D

this is only the first draft, I've got some tweaking to do. lightening holes, drill, tap and countersink for 10-32 allen bolt and possible engraving.
 
cjensen said:
You know how I feel about it!! I can't wait for mine!!:cool:
Click to expand...

yep, you get #2, since we've been tossing this idea for a while. Don is on my list for #3, since his RV-7 is the first -7 I ever sat in. Oh yeah, I get #1. IF you guys like them and there is enough interest, I may try to whip some out this winter....But for now I need to get back to summer RV building...that canopy isn't going to cut itself.
 
Very nice, Brian!

I do wonder, however, if the knob is large enough. I have manual trim on my RV-6 and often just a tiny tweak is all that is necessary to reset trim. The outboard end of the standard handle moves a tiny amount with those small trim changes. Will the knob be large enough to easily make very small adjustments against air loads at cruise?
 
Sam-I think it will be ok. I don't have any actual flight experience with it(or any RV for that matter). But sitting in my plane and test "flying it" seems easy. the knob is 1.7" dia and about 3/4" thick. The lightening holes make it easy to twist without slipping. I thought about making it larger diameter but think it may not fit nicely between the seats.

I'll get a comparison pic tomorrow.
 
Step by Step

Many years ago, I did most of my machining on South Bend , Bridgeport, Lagun lathes and mills...good stuff. When I started building the RV, I already had a decent drill press, but needed a band saw. I figured for as many hours as I'll use it, one of those cheap Harbor Fright combo band/power hacksaw would be ok. Some folks poo poo on Harbor Freight Tools. But for the garage hobbyist, they do ok. Below is some random pics.

$149 HF in hacksaw mode. It cut the 1.750" AL perfectly. TIP-let the saw do the work, don't force it.
RV7321.jpg


My dad gave me this little 7"x10" Central Machinery(HF) Lathe. It works ok, again take your time, trying to take a big cut only stalls the head
RV7322.jpg


Here's the finished 1st draft of my aileron knob and hardware and the Vans version
RV7320.jpg


And a pic of mine installed with Vans version in comparison
RV7317.jpg
 
Brian,
Just a thought, but have you considered knurling the perimeter instead of drilling all the holes? It might provide a better grip on the knob.

Nice looking bit of machine work!
 
Michael White said:
Brian,
.....have you considered knurling the perimeter instead of drilling all the holes? .....Nice looking bit of machine work!
Click to expand...

Thanks, and yes I have considered knurling. I haven't counted it out at this point. But I like the drilled look better. After a few years knurled aluminum can look a little ratty. It would definitely be quicker to make. This is just prototype, so not sure what the final one will look like.

BUT---> I sent the prototype to the test pilot. He'll do a complete shake down at various trim settings and probably some inverted stuff(just to be sure).

Then it will come back for some NDT inspections. By then the financial department should have a price calculated. A quick review by legal and we should be good to go.:D:D just kidding

I did send it to someone to test fly it for functionality. thanks Don
 
Knob avaiability

I had the same idea, but being less talanted I found a big variety of Al Knobs at Reid tool, un tapped and bought some the one I ended up with looks like a star, easy to grip
Cheers Peter
 
Brian, I got the knob Saturday late afternoon and I'll try and get it onin a couple of days. It looks like it should work great. Don
 
good deal, hope it works.
Do you have carpet between the seats? I may need to adjust the depth for clearance.
 
Well, Test flight revealed that the knob approach looks good & works ok when solo, but when 2-up, it is a little tough to operate between the seats. So here's some pics of the next attempt:

RV7.jpg


RV7359.jpg


RV7356.jpg


without a mill, there was a fair amount of hand work, so I may try another less labor intensive style.
 
Now that's a good looking piece. Brian, I'll get the other one back asap. I keep leaving it on the workbench when I walk out of the hangar. Don
 
No problem Don, Hang on to it for now. I may send this one to you for another evaluation.

I figure if I send enough stuff your way, I'll have to come get it and get some stick time while I'm there.;)
 
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