Throttle control arm

airguy

airguy

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airguy
On my experimental build, I've got an IO360 with Bendix injection, Superior cold-air forward facing induction sump and a crossover exhaust. The throttle body throttle control arm has a 1" offset to the right from the connection point and this will interfere with my exhaust when it's pulled back to idle. I'll need to replace this control arm with one that has either 1/2" offset or no offset at all. Can someone give me a source for these parts? Note that the control arm has a castellated connection to keep it from slipping, otherwise I'd seriously consider fabricating my own.

This is an experimental aircraft - no yellow tag required, it just has to be serviceable.

IMG_0654_zpse1c47127.jpg
 
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I would call up one of the fuel system repair shops, I bet they could fix you up with a no-offset arm.
 
Bend it strait, cut it to length and drill your hole. Or heck just make a new one.
 
Shorten it 1/2", drill new hole?
 
airguy said:
On my experimental build, I've got an IO360 with Bendix injection, Superior cold-air forward facing induction sump and a crossover exhaust. The throttle body throttle control arm has a 1" offset to the right from the connection point and this will interfere with my exhaust when it's pulled back to idle. I'll need to replace this control arm with one that has either 1/2" offset or no offset at all. Can someone give me a source for these parts? Note that the control arm has a castellated connection to keep it from slipping, otherwise I'd seriously consider fabricating my own.

This is an experimental aircraft - no yellow tag required, it just has to be serviceable.

IMG_0654_zpse1c47127.jpg
Click to expand...

Geez,,, The studs holding on the throttle body are WAY too long... With that said and if it were my experimental I would machine a billet spacer block that sits between the cold air plenum and the throttle body itself.. That would gave small performance gain and let the arm swing clear of the exhaust pipe.... Assuming you can move it the 1/2" or so....

Ps... the other comments are all valid too..:yes:
 
Build a new one. The curvic coupling teeth could be manually filed slots safely since it isn't a dynamic joint. Otherwise a setup that could do this would require an index table and a milling machine etc.
 
N801BH said:
Geez,,, The studs holding on the throttle body are WAY too long... With that said and if it were my experimental I would machine a billet spacer block that sits between the cold air plenum and the throttle body itself.. That would gave small performance gain and let the arm swing clear of the exhaust pipe.... Assuming you can move it the 1/2" or so....

Ps... the other comments are all valid too..:yes:
Click to expand...

That's not a bad idea, but this is on an RV9A with Sam James cowl, space is already at a premium at the front end. I'll have to check it carefully and see how far I can extend it. I really would like to avoid cutting and drilling a new hole, thus shortening the throw of the throttle cable.
 
Take it to an engine shop and just swap it for the right one. The manufacturers use a variety of throttle and mixture levers, depending on what the airframe manufacturer ordered for their airplanes. Building something like this is more critical than it appears; Continental has had their bronze arms fail and want everyone to replace them with steel arms. Vibration alone can crack an arm not made of the "right stuff."

If it was mine I'd cut the arm off and TIG weld an arm made of polished 4130 to the original hub.

But only if it was mine.

Dan
 
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