throttle arm problem
 

hey guys i have a little probelm with my supertiger 50 engine. it suffered a pretty bad crash and ever since th en the throttle arm keeps breaking off, it seems for no reason. the hole iin the firewall where the rod comes through isn't lined up perfectly with the throttle arm so there is a wee bit of tension on the rod which would then put a bit of tension on the throttle arm but i don't think its enough for it to break off. the engine runs fine but the stupid throttle arm just randomly breaks off. when i move it with my hand it opens and closes easy so i have no idea whats going on. if someone has had that problem please help me out here.

RE: throttle arm problem
 

Could your throttle servo be overstroking it at either end of travel?

RE: throttle arm problem
 

Perhaps changing over to a ball-socket type of linkage will do the trick. They are pretty flexible because of the way they connect.

http://www3.towerhobbies.com/cgi-bin...&I=LXD897&P=ML

CGr

RE: throttle arm problem
 

never thought of the ball socket one, maybe it would be worth a try. no the servo is not ever stroking, i did check that out and it seems to be just fine. i was wondering if its possible that it could be jamming up while its runningbecause its been crashed. it moves well when its not running.

RE: throttle arm problem
 

Yeah, the ball socket gives you the freedom of not having a perfectly aligned throttle rod with the throttle arm. You can actually come in from an angle that is not straight in alignment with the throttle arm.

CGr.

RE: throttle arm problem
 

You could look at the end point adjument after you change to the ball and socket.

RE: throttle arm problem
 

Also check out using a cable if your throttle arm travel will be poor with a rigid control rod.

http://somegeek2.home.comcast.net/si..._build_111.jpg

somegeek

RE: throttle arm problem
 

Well, cables do flex if they are pushed to the end points (yep, must adjust them properly). But a good suggestion because it does give more flexibility than a stiff rod does, except for when there is a ball socket at the end of the steel rod.


Somegeek.. did you ever fly that thing? It's to clean!!! ;)
CGr.

RE: throttle arm problem
 

Something you can do to limit flex is to add heat shrink over the cable. Some folks also tin the wire with solder in some areas to minimize flex where it's not needed.

http://somegeek.home.comcast.net/som...fighter_16.jpg

That is from my build thread... I've flown this plane a bunch since then! :D It's got the most time of any plane in my hangar. My favorite flier over all.

somegeek

RE: throttle arm problem
 

Ah..Ok. Looks nice, though. Nice job with that construction.

The next photo is pretty nice too. Does that intake horn do a lot for power? I heard they are pretty functional.

RE: throttle arm problem
 

I didn't see a noticeable performance boost with the velocity stack in place though it does a great job to keep the fuel from spitting out of the carb to be wasted/deposited on the plane... and it adds some bling to my engine. :D

They look really nice if you polish them up...

http://somegeek3.home.comcast.net/so...city_stack.jpg

somegeek

RE: throttle arm problem
 

you can soilder the wire to make stiffer or if you have some extract jackets laiding around , just trim it close.

Somtimes it'll bend or stick becuase that little screw that holds the barrel in place will bine in the groove becuase of burrs or nicks.


or you can just do a Z blend if you're using a rod.

put a little piece of fuel tubing over the cleves if youre using a cleves.

RE: throttle arm problem
 

You might have a broken engine mount.

RE: throttle arm problem
 

Does that engine look anything like the pics NOW lol. nice looking job. The ball link or cable both are good ideas and both fairly easy to do. Both look pretty good also. I like Bling Bling motors. All chrome would be good lol.

RE: throttle arm problem
 

somegeek,

You may want to watch using a metal clevis with at metal throttle arm. They have been know to cause interference in the past. Plastic and metal are generally the best mix.

Hogflyer

RE: throttle arm problem
 

Thanks for the advice. :) I've not had any issues with this bird yet with this setup... yet. ;)

somegeek