Carbon pushrods

Hi Guy's
Im thinking of moving the servos from the tail on my hurricane nearer to the c of g.This means that the elevator pusrods would be 1000mm long and the only way i can think of doing this would be to use a carbon inner and outer.In the days of 35meg radio i was told this would create RF noise and clash with the radio,so do any of you electronic guru's have any thoughts on this with 2.4 radio?

Such a long carbon rod inside the fuselage can certainly cause signal interference be it 35MHz or 2.4GHz and it would be safer to use a wooden pushrod with metal sliced ends for the clevis and Z bend. In the days of 27MHz wooden pushrods were the preferred option, we never heard of carbon in those far off days that's when even long metal pushrods worried us.

Alternatively snakes are possibly the easier option, flexible with no interference and easy fix ends. :whistle:

There are special receivers for use in composite fuselages. I believe a carbon rod, with suitable guides, would be better than an inner and an outer. Again, I have seen a lot of models with carbon rods and std Rx's, but not known of any problems. Now, when shall I start repairing that xxxxxxx!

Stuart

Thanks for the input guy's

Dante wrote: Such a long carbon rod inside the fuselage can certainly cause signal interference be it 35MHz or 2.4GHz and ...

I think you're wrong, Dante. 2.4g receivers cannot pass the interference to the servos. This is why we don't get glitches like we used to.

If you do go with carbon, I would not have it running inside another carbon tube...too much friction. Either run it inside a plastic tube or just support it at several locations as it passes down the fuselage. A wooden pushrod (also supported at various points) has an advantage that it will expand/contract at a similar rate to the fuselage and this will minimise trim changes from one day to the next..

As for snakes, I've read many times that they can have a lot of slop over a long run. However, Sullivan make them in 48" lengths so there must be a lot of people world-side that are happy to use them. I'd be happy to use one of the semi-rigid (blue) sullivan snakes, making sure the outer was glued in as many places as possible along the fuselage

Stuartmck wrote: There are special receivers for use in composite fuselages. I believe a carbon rod, with suitable guides, would be better than an inner and an outer. Again, I have seen a lot of models with carbon rods and std Rx's, but not known of any problems. Now, when shall I start repairing that xxxxxxx!

Stuart

The special receivers have longer antennae so that they can be placed outside a carbon fuselage. Other composites (glass and kevlar) do not need the antennae outside because they do not shield the signal like carbon does. A carbon-friendly receiver will not be necessary in a wooden hurricane even if it does have a few lengths of carbon in it.

Pete - Have you considered using a closed loop system on both rudder & the
elevator, would be very light.
Would require a short pushrod connected to bellcrank at the rear to work the
elevator.
Colin A.

Thank's guy's some good advice another route i am looking at is a pair of JR very high torque smaller servos running on 7.4 volt.

Pete - just seen your post re carbon in carbon pushrods

Support Mike Seals comments - I once installed a carbon push rod in short carbon support bushes and they fretted very badly with the dust residue causing friction so Don't do it !