trottle too close, I'm lost
 

My throttle cable doesn't have enough room to pull the throttle all the way back and i tried tomove the horn to a different angle but that will only make thecord paralel with the horn. Any sugestions? in the pic. below the cable is full back and the horn is back as well.

Thanks, Dave Trimmer

RE: trottle too close, I'm lost
 

Dave,

Not sure if this helps, but check out the bottom of this page ([link=http://saito-engines.info/engine_mount.html]Saito Engines[/link]). I can't tell from your picture, but this throttle linkage may do the trick for you.

Good Luck!

-MA

RE: trottle too close, I'm lost
 

Try making a Z bend pushrod instead of the clevis. That wil correct the problem. If you dont know what I mean, you simply get a piece of 2-56 pushrod material and make a z shaped bend on each end that you slip onto the servo arm and control horn.

Im not sure what you have going on inside the plane, is that clevis connected to hardwire pushrod or a flex plastic cable that is sliding in another plastic tube (aka goldenrod)?

Other than that the only other alternatives that I can think of off of the top of my head are moving the engine farther forward on the motor mount. Or, fabricate another control arm for the throttle that will move the connector farther away from the firewall.

OH!! [sm=idea.gif] heres another option. EZ connectors! You just cut the pushrod to length, fit the ze connector on the servo arm and throtle control horn and tighten down the setscrew and you are done.
http://www2.towerhobbies.com/cgi-bin...&I=LXAHE6&P=ML

The above Saito linkage is a good idea too.

RE: trottle too close, I'm lost
 

Dubro makes a Four Cycle throtle kit that is like the Saito photo. About $4.50 if I remember correct.

Don

RE: trottle too close, I'm lost
 

you could also get a bigger servo horn to increase the amount of pulling/pushing distance. Hope this helps.

RE: trottle too close, I'm lost
 

So what is that clevis running into? the firewall?

No law says you can't drill a bigger hole into the firewall that will allow the clevis room. I'm suggesting that because I figure you want to do the least re-engineering of what you've already "built".

Otherwise, I'd go with Mike on the e-z connector, but you'll probably have to move the pushrod to the side then.

RE: trottle too close, I'm lost
 

It's a pretty simple solution. Make the pushrod too long, come out past the throttle arm, make a U-bend in the pushrod, and come back to the throttle arm. See diagram for a better understanding of what I'm talking about.

Hope this helps

Ken

RE: trottle too close, I'm lost
 

Dave , another solution for your problem is what i am using in my model. I had the same problem as you trying to fit a clevice to my motor, and our top pilot suggested using a ball joint on the motor. It looks like a miniture tow ball, and comes with the socket to fit.It is nowhere as bulky as a clevice , and works extremely well. Dubro makes them.
Bill

RE: trottle too close, I'm lost
 

I've been there before several times with this problem. While Ken's solution is the quick'n'dirty answer, it does allow some slop into the system.

The problem with having the carb up against the the firewall is that, due to the "up and down" travel of the throttle arm (caused by the rotary, instead of linear, movement), you need a pretty good sized hole for the pushrod to be able to move in that vertical plane- while it is pulling and pushing- without binding. Note that the "vertical plane" I mentioned is perpendicular to the axis of the pushrod movement.

IMO, the best solution is to take the time to fabricate a mechanical linkage. The afore-mentioned DuBro kit is good, but you can make one out of stuff in your junk box. Basically, what you've got to do is to arrange the throttle arm to be moved from the FRONT side of the firewall. The Dubro kit bolts to the engine mount and is pretty fool-proof. See next post for a home-made job.

This is on an OS 1.08, but the principal is the same.

RE: trottle too close, I'm lost
 

Check it out. The problem here was a throttle pushrod exit point intended for an inverted four stroke. It was several inches off-center for the side-mount two stroke. And due to the fuel tank location, moving the throttle push-rod "run" was not an option. But the principal is the same; you off-set the linkage input to reverse the "vertical play" caused by rotary movement; now, the linkage is "out in the open" (as opposed to coming through the firewall directly onto the throttle arm) and has room to do its thing.

This lash-up was fabricated from a DuBro heavy-duty servo horn, and some left-over small bearings, etc. from my helicopter stash. The bearings weren't really necessary; a proper-fitting bushing will do just as well.

Yeah, it took some time and tweaking to get right. But that's why they call it "modelling", eh?;)

RE: trottle too close, I'm lost
 

I use a system very similar to what Ken suggests. If you have to much slop, you can even put a guide support on the engine mount to keep the endplay or slop down on the portion of the push rod extending out in front of the throttle arm. The EZ connector suggestion also works well.

RE: trottle too close, I'm lost
 

I see Mike East already gave ya what I was thinking is the simple solutin, the Z bend & get rid of that clevis. I never use them there anyway. RcKen's idea looks like a real good one though if you like the clevis there & want to keep it. I thnik I would go with one of those two approaches, your choice.
Good Luck Dave.