I just bought a 4* ARF. While reading the manual i saw that the ARF comes with nylon pushrods for the throttle, rudder and elevator. Is there any advantage to changing these pushrods out to something that has less flex in them? Any other tips or upgrades for the ARF would be great if anyone has any. Thanks in advance.

I immediately changed to metalic pushrods. Plastic tubes will expend with the heat and change your trim.

Nylon or any other kind of semi flexible pushrod has to be properly supported. I use Sullivan
Semi flexible carbon fiber pusrods in my Tiger 60 and Golden rod Nylon in my Tiger 2
I brace the outer shield every 4 inches to keep it from flexing under load. also I
let the outer shield stick out of the fuse a few inches at the tail.

Problem I see is that I built mine from a kit so bracing was easy before covering.
Sig is a good manufacturer and I think they would brace the pushrods pretty well.

Also instead of insering the small threaded end into just the tip of the pusrod get a long piece
of 2-56 pushrod that is only threaded at the end, Install this pushrod a few inches into the flexible
pushrod and glue.

In my picture you can see the metal pusrod is inserted into inner rod past the point where it goes into the
outershield. which I never cut off. It is very strong and doesn't flex.

Stay with the nylon rods for your throttle. It will prevent any RFI from a metal to metal contact between the engine and the throttle servo.

Actually, there is nothing wrong with nylon pushrods PROVIDED that the outer sheath is adequatly supported. Unless you live in an area where you get sudden 50 - 60 degree temperature changes I wouldn't worry about any possible trim change.

If Fadi81 was correct, how come DuBro and Sullivan sell a ton of them each year ?

The stock rods are fine in a plane at this level. Do make sure they are properly supported. Trim shifting? Yeah, maybe a click or 2 from day to day. If you're flying a 4* you can handle that. You'll see more than that just from fuel burnoff.

I fly a Venus II with an OS 1.20 AX and use the Sullivan Carbon Composite flex rods. They work just fine and will in your Four Star 40. The key is to make sure that they are secured at points inside the fuselage. I presume that if the plane came with these type of rods, the tubes that are inside the fuselage are probably already set to something solid so they don't flex. You can always open up the bottom of the fuselage by carefully removing the covering, applying the appropriate glue to the tubes against the formers within the fuselage, then re-applying the covering. That's pretty much what I;ve done with my Sullivan equipped aircraft.

DS.

I finished putting my 4*40 arf together about a week ago. The provided push rods are fine and the plane flies great, stays in trim, and the support tubes are glued in there VERY good. I put the glue weld to a pretty harsh test inadvertently.

Thanks for all the info guys, it was very helpfull.[8D]

My 4* is kit built and has seen some hard times and been rebuilt a few times. I`m still using the stock push rods. I did do the same mod as overbored77 with the 2-56 rods.
Your gonna love this airplane. What engine are you going with?

For the time being I went with the Super tigre 40. Its just what our club requires if i decide to enter the 4* races they hold.