LT 40 throttle linkage
 

I'm putting together a LT 40 with a Magnum 52 four stroke. I am trying to figure out the best way to run the throttle linkage. With the throttle arm behind the cylinder, there's no way to bend a push rod to connect to the arm. I know there is a bell crank system that you can connect to the engine mount and go thru the firewall and then back to the throttle arm. Does anyone have some pics of a set-up like that? or an alternate method of routing the linkage?

Thanks

RE: LT 40 throttle linkage
 

Sure there's a way. you will need one of the ez connectorson the carb throttle arm. set this up without the servo connected at first. put the pushrod in the fuse bend a ninety degree angle when it comes out the front. line it up with the ez connector on the throttle arm. Now here's the important part. moving the pushrod from inside the fuselage work the throttle from full closed to full open. make sure the complete travel is smooth and the carb really closes all the way as long as opens all the way. you may or may not have to change the angle a little bit but it is possible. then when that is all right hook it up with another ez connector at the servo arm. use the ez connector at the sevo arm for the final travel adjustments. Don't forget some blue loctite on the ez connector screws.

As far as the bellcrank goes it will work also but it is nine bucks and just adds more stuff to come loose adjust etc.

Dennis

RE: LT 40 throttle linkage
 

yea, i did something like that on a rascal but it seemed to flex quite a bit.

thanks

RE: LT 40 throttle linkage
 

you should'nt have any flex the two ninety degree bends are going to be approx. a half inch apart so flex will not be an issue. look at a z-bend at a servo arm there is no flex at all.

Dennis

RE: LT 40 throttle linkage
 

Here's a couple of pics, as you can see the throttle arm is really close to the firewall. You're saying pushrod thru the firewall then a 90 degree turn to the arm. I'll have to make one more 90 at the arm to connect it right?

RE: LT 40 throttle linkage
 

here's a test fit, not connected yet but it looks like it'll work, I'm not crazy about using ez connectors but like you said I'll use plenty of lock-tite

I hope this helps someone else with this set-up.

Thanks for your help, Bodary

RE: LT 40 throttle linkage
 

Yes that will work. hard to tell from the picture it looks like you may have been better off. either redrilling the hole for the throttle pushrod to get closer to the throttle arm. or maybe turning the carb 180 degrees and then redrilling the pushrod hole. Like i said hard to tell right from the picture. if you've already modified the fuse sides to clear the needle valve and the exhaust. you're going to have to live with it otherwise i think you'll be better off turning the carb 180 degrees.

Dennis

RE: LT 40 throttle linkage
 

Back to the drawing board, it's got too much slop in it. Turning the carb 180 won't work without making major changes in servo location, due to tank location and nose gear pushrod location.

Theres got to be a better way. Surely someone has a 4 stroke in a LT 40.

On the Rascal I had to put a horseshoe bend in the pushrod coming out of the firewall, I wanted to avoid doing that on this one.

Thanks

RE: LT 40 throttle linkage
 

"Theres got to be a better way. Surely someone has a 4 stroke in a LT 40."
My first plane about three years ago was an LT-40 with a Saito 56. I spent a lot of time trying to bend a rod to make it work. What I ended up using was a flexible metal cable inside the plastic tube. Redrill the firewall and put it where you have a straight shot at the throttle arm. Each end is secured with an ez link. When there is room I add a backup ez link on the cable in case the primary one gets loose. That way I can still close the throttle. This is the only method I have used on several models. Throttle hookup is generally painless. From your photos it appears you will need to run it above the tank if there is clearance. You should have a lot of fun with that plane.

RE: LT 40 throttle linkage
 

I have an arm my control rod attaches to my engine mount rail along side the engine - then a seperate rod from it back to the carb arm. This setup works good on my 4 stroke on my 4 star. I think this is a dubro product.

RE: LT 40 throttle linkage
 

This plane is a birthday gift for my 12 year old son. Once again Sig has impressed me with the quality of this arf. I am also putting together a DPM super cub and I have to say Sig arfs are more impressive (see my thread regarding DPM ).

As far as the throttle linkage, re-routing the pushrod tube looks like it will be hard to do due to the fuel tank location. I would really like to see a pic of the bell crank system that Delman mentioned.
I'm going to keep bumping this for awhile and hope someone can produce a pic. RCU has never let me down ;)

Thanks for the input

RE: LT 40 throttle linkage
 

Here is the link for the Dubro bell crank from tower http://www2.towerhobbies.com/cgi-bin...?&I=LXD939&P=7

and here is the pic

RE: LT 40 throttle linkage
 

Thanks, looks like it might work if it will fit between the mount and fuse.

RE: LT 40 throttle linkage
 

How about just running a new throttle pushrod in the center of the fuse. That's what I did on H9 Twist was really easy to do.

Joel

RE: LT 40 throttle linkage
 

That might be a possibility if I can get it around the fuel tank

thanks

RE: LT 40 throttle linkage
 

Well here it is, I followed Jlank's advise and ran the pushrod down the center it works great.

Happy Birthday Kevin!!