pinnedup

I’m putting the finishing touches on my 4 Star 40. I used Sullivan Gold N Rod control rods. Per the Sig building instructions (for the stock control rods) I trimmed off the outer Gold N Rod sheath where they exit the fuselage. Reading the directions for the Gold N Rod control rods they say the inner control rod should not extend unsupported more that one inch from the outer sheath, the span from where the control rods exit the fuselage to the control horn is about 2.5 inches. Would this unsupported span be a problem for the Gold N Rod control rods? I have an extra set of short metal control rods from the kit that I could insert into the inner Gold N Rod control rod for support, should I do this to stiffen the Gold N Rod control rods?

Also, I ran the throttle cable outside of the engine support, the throttle cable is at the correct elevation but about ¾ inch out from the side of the throttle linkage on the engine (a TT Pro 46) carburetor. If I use the solder-on threaded coupler and a plastic cleaves at the throttle arm (per the building instruction), the solder-on coupler rubs/binds against the engine mount. If I switch the throttle cable end for end and use a (metal) solder-on cleaves at the engine throttle arm the throttle cable is better able to make the bend to the engine throttle arm. However, Sig recommends against a metal-to-metal connection at the engine as it mat cause electrical noise that could affect the radio. I could also trim away some of the engine mount to smooth out the radius for the solder-on threaded coupler. I have about 1/8 inch clearance from the prop to the checks on the 4 Star. Suggestions?

Thanks,

kbear

I have used longer pieces of all thread to replace the supplied metal on Gold-N-Rods before. I screw the rod as far as I can so that the inner rod never exits the sheath and the all thread plus clevis covers the needed distance. I wish I had a photo. I'm not sure that was a good explanation. I've had the inner rod bend at the point were the treaded rod stops before. By keeping this area inside the sheath, I have been able to avoid the problem.

As for the Throttle cable, I always use a plastic clevis now for the reason stated as well as to save the throttle arm in a crash. I'd say use a Dremel tool or something to grind away what you need for clearance, as long as it won't compromise the structure of the mount.

Just my 2 cents, hope it helps.

saramos

I agree with kbear on both suggestions. Use longer metal pieces so the inner plastic rod extends no more than the recommended distance. Grinding away some of the mount web so the cable makes clearance will be fine as long as you don't have any sharp corners or grind into the rails themselves.

Scott

quepasa

All of the above is good especially for the controal surfaces. A good test is to grab the controal surface by hand with the radio OFF, and flex it. If the servo turns without deforming/flexing the pushrod, its stiff enough no matter how long it is.

As far as the throttle linkage tho there is another way. If you have a "Z" bender and some single-strand wire like mechanics or bailing wire. You can make a "z" to connect to the throttle arm, then bend a larger "Z" into it to get around whatever is in the way. Drill a hole in the firewall that fits the wire and run it back to the servo arm and connect it with another "z". (The wire must be supported by going through the firewall and bulkhead to the servo.) You can bend as many "Zs" as needed to get around the fuel tank etc. Adjusting the length is nothing but bending a "z" tighter, or looser. The wire will hold its shape, and since its relatively soft, won't hurt the servo in a crash as it will just bend. If electrical noise is a worry for you, use a ball-socket connection on the throttle arm and solder the brass piece to the wire. A 90deg. bend can be made from there to get around the obb-stikle. I would not hesitate to go metal-metal though. The ball-bearings inside the engine probably make more electrical "noise" than the wire/throttle arm would. JMHO. Others could advise on this better than I. Hope this helps! Q.

edit; Get a "Z" bender if ya don't have one! Its one of those gizzmos that ya never knew how bad ya needed, til ya have one!

pinnedup

Thanks for the sugestions; I plan to follow kbears suggestions and use all thread to replace the supplied metal on Gold-N-Rods. I will use a plastic clevis on the throttle leakage and trim the motor mount gusset.

Thanks again,