Throttle linkage for 4s
#1
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From: MD
Hello,
I am currently building a Sig Four star 40, with a O.S. 52 Surpass for power. I built the fuse today, and noticed that the throttle linkage will go right through the engine mount. I was a little concerned about the structural integrity of the engine mount with a hole drilled through it, and was wondering if anybody had run into this problem, and what their solutions were.
Kurt
I am currently building a Sig Four star 40, with a O.S. 52 Surpass for power. I built the fuse today, and noticed that the throttle linkage will go right through the engine mount. I was a little concerned about the structural integrity of the engine mount with a hole drilled through it, and was wondering if anybody had run into this problem, and what their solutions were.
Kurt
#2

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From: Great Falls, MT
I'm also building one now. Using a Magnum 52 4 stroke. I've mounted mine inverted. The throttle arm was close to the center line of the engine and that looked like it would be a hassle to run the servo cable. I took the carb off and flipped ti around, now the throttle arm is to the side of the engine. Now the throttle cable will be clear of the tank and the engine mount. Hope that helps, Mike.
#3
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On most of my 4 strokes, I run the throttle pushrod out near the side of the fuse and well out past the throttle arm and then make a hairpin turn in it and come back to the throttle arm on the carb. This makes it easy to put on a clevis without running into the firewall or having binding due to friction.
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From: gone,
I put a .91 FS on a 4*60. To get the throttle lnkage set up, I bolted a straight bellcrank (made from a servo output arm, a screw and a bushing from a 90 deg bellcrank) on the side of the engine mount, just clearing the cheek cowl. The bellcrank is forward of the engine mounting bolts in the beam, so no strength issue to worry about. It also let me put 2 clevices in easy reach for adjusting the linkage. A couple of bends in the rod from bellcrank to throttle arm and a Z bend into the throttle arm. The pushrod from servo to bellcrank is essentially straight.
#5

I usually use a ball link ball attached to the throttle arm, and a cut down solder on threaded end for a clevis to which I screw the socket end of the ball link to (DuBro style). With a little work, you have a very direct linkage. Use another threaded solder link on the other end of the throttle cable with a clevis and make your adjustments at the servo end. Then finish off with the radio end point adjustment and you're done.[img]i/expressions/face-icon-small-smile.gif[/img]



