4-stroke on US 60
 

Hi gang, quick question. I am building an RCM Ultra Sport 60 from plans and am going to use a Magnum 91 4-stroke. The problem is the control linkage to the carburetor. I am using a GP engine mount. The way the engine bulkhead around the engine is constructed the engine mount touches the inside of the balsa bulkhead top and bottom (as in top in bottom of the plane-side mounted engine). Does anyone have a suggestion how to mount the throttle linkage? I am almost done with the plane and would like to do this right. Has anyone done this before? I had considered using the Dubro 4-stroke linkage modification but there is no room to attach the pivot on the side of the engine mount. Any ideas? Thanks!

Travis

RE: 4-stroke on US 60
 

got a picture?
a couple thoughts
does it help turning the carb 180 degrees. cause it does flip over. also the set screw on the arm allows it to move around 180 degrees. Also a flex cable can make it around objects very well.
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXK055&P=0]flex cable[/link]
solder the clevis on one end and use a screw lock connector on the other [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXK098&P=0]screw lock connector[/link]

RE: 4-stroke on US 60
 

I had about the same problem putting a 120FS on my Mustang. I modified a control horn for a steerable nosegear, screwed it into the mount, ran the linkage from the servo to that, then back to the throttle. If I can get a break in the rain in the morning I'll take a snapshot and post it.

RE: 4-stroke on US 60
 

I have the exact same plane, with the exact same engine, and I had no problem whatsoever setting it up. I'm having a hard time following your troubles. If you'd like, I can post some pics, but it would be tomorrow after work before I could.

PS. My engine is also mounted on it's side.

RE: 4-stroke on US 60
 

Hi
This is how you do it, loop the pushrod back 180 degrees.
Works perfectly!

RE: 4-stroke on US 60
 

Thanks for the ideas guys. I did manage to get a few pitures that might help with understanding my problem. It seems to me that there is quite a bit of "other stuff" in the way to set up the linkage. At the same time it seems like the arm is so far in. Any new ideas based upon the pictures? Thanks-

Travis

RE: 4-stroke on US 60
 

the easiest way would have been to mount the engine on its side. whoops. Do as test said and run the loop back pushrod. Don't be affraid to put a hole in the engine mount. make sure you plan ahead

RE: 4-stroke on US 60
 

Thanks for the comment. Actually the engine is on the side. I just took the picture right side up so the body did not tip over. It is a bit easier to see this way as well.

Bending the linkage 180 degrees probably will be the way to go.

Travis

RE: 4-stroke on US 60
 

hmmmm .... you're right. With the overabundance of free space in the engine compartment, bending the pushrod is probably your best option, but this is how I did my bipe and P51

RE: 4-stroke on US 60
 

Can you flip the carb around to get the throttle lever more offset from the engine?
Then run the pictured 180 degree loopback pushrod.