I hate 4 stroke throttle linkages
 

I had one finally setup, and I couldn't get enough throw out of the servo to move it, I think it will take a longer arm to fully extend and close the arm.


Is it normal to have to bend the rod a significant amount to get it hooked up correctly to one of these motors? I know I will never build a kit intending to use one without the motor on hand.....

RE: I hate 4 stroke throttle linkages
 

Yes

This LT40 originally had a Tower 46 engine and now has a OS 52 four stroke The throttle rod comes out of the firewall in the original position and notice the bends in the throttle rod
http://image2-6.rcuniverse.com/e1/ga.../lg-123515.jpg

RE: I hate 4 stroke throttle linkages
 

Hmmm.....


I'll have to make the trip to the LHS for more 4-40 rod monday.


thanks for the pic btw, that's pretty much how I did it, I just need to get some bending pliers so I get a nice precise bend this time.

RE: I hate 4 stroke throttle linkages
 

4-40 rod may not be hard enough

I use .060" piano wire

I also use one of these on the servo arm so I can adjust the length

http://www3.towerhobbies.com/cgi-bin...&I=LXK099&P=ML

RE: I hate 4 stroke throttle linkages
 

Ideas on where to acquire that?

RE: I hate 4 stroke throttle linkages
 

I got the piano wire at the hobby shop in town.



Power Heli's LLC
dba Power R/C Hobbies
Bryan, TX 77803
(979)779-2151

American Aerospace
6113 Highway 21 East
Bryan, TX 77808
(979)778-9464

RE: I hate 4 stroke throttle linkages
 

I'll look for it. Hobby lobby may be a source, or a hardware shop.

RE: I hate 4 stroke throttle linkages
 

Quit fighting the linkage. Use a cable and route to the carb. Remember, if the linkage is way out of alignment, rotate the carb 180 and move it to the other side.

What you may run into is that there isn't enough movement to the firewall side. In that case, I shorten the cable end up. I cut the brass solder on so it had 1/2 the length at the cable end. I cut the threads off so there is just about 3/16" thread. I use a snap on ball joint and I cut the thread end of it so it bottoms on the shortened brass adaptor. Then adjust the horn on the carb so the carb is full in the direction of the firewall just prior to all of this bottoming out.

I tried all of the 4 stroke linkages, bent wires, etc and a direct connection is the best. I have used this direct connect it eight different planes over the last three years. That includes engines mounted upright, on their side and 3/4 inverted and I've yet to find a plane that I had to use a bunch of bent wire to make the throttle work. Remember, you don't have to use the same throttle linkage hole in the firewall. You are free to drill another where you need it. The cable linkage will snake around the fuel tank. The photo is of one of my 4*60's with the shortened linkages.

Don

RE: I hate 4 stroke throttle linkages
 

I just set mine up as shown. Lots of adjustment.

Cheers

RE: I hate 4 stroke throttle linkages
 

With the cab;e- is that just run directly though a piece of tubing? My problem is my carb is either dead center of the plane, or in an awkward position on the side of the firewall.


How is that bellcrank attached to that motor mount? Is it just a screw or a bolt with loctite on a jam nut?


My biggest problem right now is, the cheek of the tiger make anything like that a real PITA(I've notched it for the needl at this point as well...)

RE: I hate 4 stroke throttle linkages
 

The belcrank is attached to the engine mount with a self tapping screw. It does not come loose. The cable is setup as a normal throtal setup.

Cheers

RE: I hate 4 stroke throttle linkages
 

Here are two more setups

RE: I hate 4 stroke throttle linkages
 

I fly mainly 4 strokes and have tried many different setups. The flexable cable has worked the best for me . It will snake around the fuel tank and still operate smooth as silk. It runs direct to the carb , no wire bending or pivots to set up and it`s very light weight. The other setups work fine , but coming out of the firewall right behing the carb, the cable is the cleanest looking and lightest way I`ve found to go.
I generally use Dubro 20 in flex cable , their only a couple of bucks. Sorry the pics dont show what I was looking for, but in the SlowPoke , can you see a cable. I comes out right behind the engine, on the Ultimate , you can see where the hole is for the cable to come out.
Just finished a Extra 260 and will try to get you some better picks , after I plow all the snow we got last nite .

RE: I hate 4 stroke throttle linkages
 

After using my first flexible cable on the 4* I built, I'll never use wire again. And after using the flexible cable and the screw lock connectors like w8ye linked too on my GP Corsair I'll definately never use anything else.

RE: I hate 4 stroke throttle linkages
 

All of the above but most the time I use cable if I can.

RE: I hate 4 stroke throttle linkages
 

Mission successful after much cursing. Ran the cable down the right side of the fuse, used a screw type connector on the throttle arm and it work like a charm.

RE: I hate 4 stroke throttle linkages
 

If you are happy - We are happy

RE: I hate 4 stroke throttle linkages
 

One more option is to use a micro servo in the engine compartment. I saw this setup a couple of years ago, and the RC'er said that it worked just fine. He put a think coating of RTV or silicon on the servo, except for the main shaft area, and fabricated a mount in a position that allowed him to do what he wanted with the throttle.

This will work, of course, if there is enough room in the engine compartment.

CGr.

RE: I hate 4 stroke throttle linkages
 

I had considered that but the main problem wasn't where the linkage was coming from, but the clearance behind it on the firewall.

RE: I hate 4 stroke throttle linkages
 

I've tried to do what you have set up in the first pic with my Saito .82 on my SS60, but I seem to have too much flex at the extreme ends of travel and I'm not getting full idle or full open. Any ideas on how to solve this? I may look at it when I get home tomorrow and see if the cable type might work better.

RE: I hate 4 stroke throttle linkages
 

If Minnflyer's set up doesn't work, something is wrong with your throttle

The throttle must move freely full travel

RE: I hate 4 stroke throttle linkages
 

Here's the link that will fix your problems. http://www3.towerhobbies.com/cgi-bin...&I=LXD939&P=FR

RE: I hate 4 stroke throttle linkages
 

Just go [link=http://saito-engines.info/throttle_setup.html]HERE[/link] to find out about Satio engine setup. Regardless of how you setup your throttle you still need to set the throw and mechanical setup to work correctly.

Cheers

RE: I hate 4 stroke throttle linkages
 

Not to sound like a broken record, but these work great. http://www.shopatron.com/product/par...161.5165.0.0.0

RE: I hate 4 stroke throttle linkages
 

Actually I didn't even have room for the soulder clevis. I had to use two screw type connectors.....

RE: I hate 4 stroke throttle linkages
 

I've used this stuff at times

http://www3.towerhobbies.com/cgi-bin...OD++&search=Go

RE: I hate 4 stroke throttle linkages
 

I use the screw connectors also. Just add a little solder to the cable , where the screw grips , then when you tighten the screws down , gives it something to bite into. your throttle arm on the carb , can be just about up against the firewall and still works great

Picture worth a 1000 words , so I try to get you some picks , while I`m out in the shop tomorrow .

RE: I hate 4 stroke throttle linkages
 

[/quote]
If Minnflyer's set up doesn't work, something is wrong with your throttle

The throttle must move freely full travel
[/quote]
My throttle arm moves just fine, with no binding at all, but even static, if i push it to one end or the other it tends to want to roll back away from the stop just a little. The pushrod I have tried to use to this point, just doesn't have the holding power at the ends due to the 2 90 degree bends in it. Because of it's location and the narrowness of the fuse, I'm not able to reposition the exit from the firewall. I'm gonna have to try the cable style for more positive control I think.

RE: I hate 4 stroke throttle linkages
 

There nothing positive about a cable when you are trying to push with it

I have used them and they worked great but the end had to be aligned with the engine and the servo. The cable guide has to be secured against movement

RE: I hate 4 stroke throttle linkages
 

And I think that's where I'll have the most trouble because in my case (if I remember correctly) it pushes toward idle, and pulls toward WOT. I may be able to remove the throttle arm and re-install it 180 degrees from it's original position to get it more inline with the exit and make a guide in the engine compartment to minimize flex.

RE: I hate 4 stroke throttle linkages
 

If you need the cable to be stiff in a certain area , wicking a little solder in the weak place stiffens the cable . and the cable pushes just fine, if you have it set up right. Dont cut the tube at the bulkhead , where it comes into the radio compartment . Cut it a 1/4 inch short of the sevo arms farthest forward throw. If it still flexes alittle , add a standoff, to support it. Heck , most the time I use a micro servo , they move that freely .
Most throttle arms have a set screw so you can rotate the arm. Most , if not all my installs have been with the arm up. . Just seemed to work out that way.
If your wire flexes to easliy, you may be using to soft of metal rod or if you have done a lot of bending on it , have taken the temper out of it. All the fixes mentioned should work for you, not sure what you`ve got going on, but dont give up.

RE: I hate 4 stroke throttle linkages
 

I made sure my tubing was secured at several point along it's length, and the terminal ends are never more than an inch from being inside the tube. I've got almost 0 flex.

RE: I hate 4 stroke throttle linkages
 

Here's two set up's the first is a Saito 72, the second is a Magnum 70
http://i154.photobucket.com/albums/s...7/100_1818.jpg
http://i154.photobucket.com/albums/s...7/100_1816.jpg
http://i154.photobucket.com/albums/s...7/100_1815.jpg