Edwin

My Feedback: (2)

I was sitting here wondering why I spent $24 on 8 dubro giant scale control horns when a different way hit me like a phone book in the face. Wish I'd thought of it before that. Its fashioned after the bolt style control horn. The bolt goes thru the control surface (nothing new there). I used an aluminum hex 1/4"x1/2" - 6-32 threaded standoff and drill and tap a 6-32 hole close to one end. The hole I drilled threads onto the bolt in the control surface. This gives me the 90deg turn I needed. Take another 6-32 bolt (around 3/4" or so) and thread a heavy duty horn bracket (Tower p/n LXD949) onto this bolt up to the screw head. Then screw this bolt into the aluminum standoff up against the other bolts threads, locks it all together. The beauty of this setup is you can adjust the horn bracket if its not over the hinge line, its strong, and its cheap. Will definately do this on the next plane.

Edwin

Kaos Rulz

I'm having difficulty invisioning this. Do you have any pic's?

Edwin

My Feedback: (2)

Give me a little bit and I'll see what I can do.
Edwin

Edwin

My Feedback: (2)

Try this, a picture's worth all these words.
Edwin

SeacretsOceanCity

Why cant you just put the horn bracket on the 6/32 bolt that goes thru the control surface. Keeping it simple just get bigger horn brackets or drill them out

CafeenMan

I think 512 has the right idea. KISS.

Edwin

My Feedback: (2)

The horn bracket wouldnt be over the hinge line, if I understand you correctly. Which brings up another question on control horn to clevis geometry. Does it HAVE to be over the hinge line? I've always dont it that way cause..... thats the way I was taught and always done it. Does anybody do it the other way?
Edwin

DBCherry

My Feedback: (4)

If you moved the vertical bolt to the LE of the surface it would be close. If need be, use a larger horn bracket.

If the bracket isn't over the hinge line, your control rod would have vertical travel during the horizontal movement. I don't think it would be disasterous for most sport planes, but it's not a good habit to get into.
Dennis-

Edwin

My Feedback: (2)

HMMM! The reason I moved it back was to set the bolt into more meat instead of at the edge. I'm too concerned with stress's that close to the edge. Those horn brackets are only 1/4" or so. The dubro's (I think) are about 3/4". Enough to set the bolt in good thick wood. The only longer horn bracket that I know of is only sold by dubro in the heavy duty control horn set. I havent seen them sold separately. Other than that, I dont think there is a larger horn bracket than 6-32, is there?
Edwin

SeacretsOceanCity

That will work. I never worry about (over the hinge line) as long as your close and both ailerons are the same.In a pinch you could heat and bend the vertical 6/32 bolt just dont weaken it. or put them in both in a vise an hit em with a rubber hammer for the bend.

SeacretsOceanCity

If your that concerned BEEF it up with some ply

SeacretsOceanCity

Ok here is a better idea for you. Go to lowes or ace and get some 1/16 or so angle aluminum cheap stuff then cut your own with a hack saw or whatever you have then you can have both MEAT and centered over the hinge and the BONUS of LOW LOW cost

Edwin

My Feedback: (2)

It already IS beefed up with ply. Sorry, I'm not going to drill a hole that close to the edge of the elevator or rudder. Seems like drilling and tapping is easier than hacking out a control horn from aluminum angle. FWIW, I keep metal around the shop to make gizmos on a as required basis.
Edwin

LuvBipes

My Feedback: (4)

Edwin/DBCherry, thanks for coming up w/ a great money saving idea. Being off the hinge center line can be accomodated for also by moving the servo arm from the 90 degree position and/or adjusting the throws via a computer radio.

I didn't know you could buy the Dubro Heavy Duty Horn Bracket separately. You guys just saved me some money.

SeacretsOceanCity

Well FWIW the more bells and whistles the more chance something can fail. I have made and seen aluminum angle utilized and it looked better than any factory horn I ever saw. Sounds like your gettin salty just trin to give some ideas.

Flyfalcons

The picture in post #8 is standard for the Midwest Extra. Epoxy the bolt into hardwood located at the front of the surface and you're good to go. However, the Dubro is a much better design.

the troll

Yes... I have used the setup that is depicted in post #8 in 1/4 scale with some success but the bolt was indeed very close to the hinge line.

J_R

Edwin

What a great idea! I just got done putting horns on a plane and having to search through several hobby shops to find ones where the holes would be over the hinge line. What a pain!

Your idea here is perfect. The only suggestion that I would make is to put a jam nut against the standoff, on the vertical bold, so that it does not “work� and eventually strip the threads or cause electrical noise.

The holes must be on the hinge line or we introduce differential into the surface. That is what we used to do intentionally in the days before computer radios. It’s always better to get it set up right mechanically then to try to compensate with the radio, particularly on a plane with a symmetrical airfoil, where you don’t want any differential.

A couple of years ago, a guy named Brian DeFelice came up with a really simple way to do pull-pull… but, it relies on making sure the holes are NOT on the hinge lines. If anyone has not seen his system, which relies on the ackerman principle that cars use so that the wheels that steer travel different distances in a turn, here it is:
http://members.cox.net/bdfelice/ read the section on ackerman, then the one on pull-pull.

JR

fwman1

My Feedback: (22)

Cool. Thanks.

AlphaWhisky

Flyfalcon`s post re the method being as specified for the Midwest Extra is exactly what I used on my G-38 powered Midwest. One horn sheared off flush with the aileron on the first testflight. ( I got the model home without further damage)

I replaced it with another of the same and ran it up on the ground, and the one on the other side then sheared off!

With this experience behind me I now fabricate my own horns ex ali angle. I custom-make them for each project and you can off-set them to suit any application.

I would be wary of the 6-32 bolt used as a post as detailed. I reckon it at least needs a full-height shroud around it - maybe a short length of neat fitting ali tube held down with a nut on the top. You could drill your horizontal attachment into this lot - but it does seem like a lot of hard work compared the the aluminium angle method.

Alan W

LuvBipes

My Feedback: (4)

Alan, I agree partially with you. 6/32 bolts sould only be used on planes up to around 8 lbs (60/90 size). On larger planes steel 8/32 bolts will do the job. I beleive the Dubro horn brackets have enough "meat" in them to allow them to be drilled/ tapped out to 8/32 size.

J_R

It's not so much the vertical bolt that is impressive. I am partial to the MK horns that use a triangular foot that is not likely to pull out. It is the ability to put some sort of adjustable threaded rod at 90 degrees to it. I prefer ball joints, like the Dubro DUB259's or the MK ones. The threaded shaft sizes need to be changed to suit the application, but the idea of being able to adjust the hole on the horizontal axis is genius.

JR