dakoris73

Hello everyone;

I'm still a bit of a newbie with a fun and interesting dilemna........ I am working on a Tower Trainer to keep my nerves in check, and I also wanted to change it up a bit by adding a Magnum 52 4 stroke instead of a standard 46 2 stroke. I've got everything to match up, with the exception of the throttle. If your familiar with the throttle setup on a Magnum 52 4 stroke, the carb is on the opposite side of where the throttle linkage is setup for. It also sits right in the middle of the Motor Mount against the firewall. I have tried making a connection with this using a 90 degree connection right into the throttle hole, however that created a metal to metal connection that caused some interference with the radio signals. So now I am trying to figure out a different setup for the throttle connection, but not sure how. I've included some pics of how I initially had it set up, but wanting to know if there are other options or ideas on how to get this throttle linkage to work without a metal to metal connection.

Thanks,
Dax

Delta3

Why don't you undo the carby at the back of the engine 2 or 3 screws (I believe) and turn the carby around the other way. I checked my Magnum 52fs and it is quite easy to do. Then just take a piece of throttle wire, put a 90 degree bend in it (you will need to measure and be accurate) then you can run you accelerator from the side of the plane it feeds from. Just need to put a bend in the wire that fits in to the throttle arm ( s bend will do the job) so it doesn't come out and problem is solved. Takes a bit of fiddling around but as long as the throttle wire is reasonably strong it works fine with no modication to the air frame only the throttle wire and the position of the carby. The carby is designed to allow you to turn it around

RCKen

My Feedback: (9)

These are common problems with 4-strokes, and easy to resolve

Most 4-strokes allow you to reverse the carb mount, which will let you move the throttle arm to the other side of the engine. It's usually as easy as removing a couple of screws, turning the carb, and replacing the screws. that should solve your routing problem.

As for the distance from the firewall to the carb arm, there is a simple solution. Run the pushrod out of the firewall past the throttle arm and then loop or bend it back to the throttle arm.

Ken

opjose

Yup RCKen's solution is the easiet.

Also note that because this is a common problem there are other options too...

e.g.

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD939&P=7]Four Stroke Linkage - Click me![/link]

Campgems

My "fix" for the 4 stroke throttle linkage is to use a ball on the throttle arm. Ithen use one of the plastic snap-on ball sockets that I have shortened so there is just 1/8" of length behind the socket. I use a brass threaded end for cable and shorten both end of it so the overall length is 1/4" Solder to a cable, and then screw on the ball socket. This makes a very compact arangement. The carb needs to be positioned so the throttle arm is on the outside vs centered like your photo. Just loosen the manifold to head screws quite a bit and remove the carb to back place screws. Plull the carb off the manifold and turn it 180 and put things back together. You can position the throttle arm either hi or low depending on how you need to route the cable.

I've used this setup on all my engines, from the 52 up to my Saito 180. The later had a chalenging carb setup and I attempted to use Kens U shaped linkage, but the only wire that was flexable enough to fit the pre-installed cable route, was to flexable to give repeatable throttle settings. Iended up modifying the cheeks on the Twist 150 and going back to my regular method.

Don

Clay Walters

So far I've only done 3 with Magnum 4-strokes and have used cable mounted to both the throttle arm and servo arm with the cylinder connector that you pass the cable thru and clamp into the hole with a set-screw. Ofcourse I run the stiff tubing the cable passes thru the cabin and firewall as much in-line between the servo arm and throttle arm as possible with supports along the way to keep it from flexing. This and because it takes very little to actuate the throttle has worked out very well for me.

Sorry I don't have any pics of this.

Regards,

Clay

oldvet70

My Feedback: (10)

I have a friend who, when faced with the exact same combination of airframe and engine, turned the throttle arm 180 degrees upward and routed the throttle cable out the top front of the fuselage. It looked a little odd but it was easy to do and there was plenty of clearance.

aerofly0610

Interesting, I have a mag 52 and it would fit on the mount of my tower trainer.  Did you put in a different mount?  I had to use a GMS 47, then I stripped the glow hole in the head (parts back ordered),,, now I'm down to an OS 40la.  Maybe if you got some pointers I can get my magnum 52 on my trainer  [8D].

dakoris73

Thank you all for your suggestions / responses.

OLDVET70 - I too have thought about doing just that to make things easier to setup. just not sure I like the look of the throttle arm sticking straight out like that.....

AEROFLY - at present, I am using the Engine Mount that came with this trainer, but what I had to do is to widen the front holes on the engine itself just a hair and then line up the front holes with the front holes of the motor mount, then just screwed it in with the brackets. The back of the brackets will bend a bit, but it does work and looks good sitting up front there.......

Another issue that I am seeing is that the way this throttle/carb setup is puts the linkage directly in the middle of the engine, so using a U Hook as mentioned above wouldn't work due to the engine being in the way. I haven't tried turning the carb around yet, but may consider trying this as well, but it still leaves the throttle in the middle of the engine block. So I'm still not sure what options can work at this point. I will try to get some more "clearer" pics on here to show my dilemna sometime this weekend.

Thanks again for your inputs, and please keep them coming as this is my first experience with a 4 stroke engine........

Dax

Charlie P.

The .46 2-stroke would have given you more acceleration and top-end speed. But a 4-stroke is a gentleman's engine and I approve. ;-)

rgm762

My Feedback: (4)

i ran into the same problem with my VQ Pilaits PC6, running the conventional "pushrod" for the throttle was a major pia, so I went with a cable like Clay Walters describes, the cable has a lot of flexibility that allows you to route it in several different ways that you can't do with a stiff rod. i was able to route mine under the tank and line up perfectly with the throttle arm.works great, this is what I used


http://www3.towerhobbies.com/cgi-bin...?&I=LXFU98&P=0