Bowden cable as an elevator push rod

[Russ P]

I'm building an old Gloster Gladiator kit and the cable run to the rudder and elevator has a few bends which slightly restrict the rod movement of a Sullivan semi flexible rod so I thought of using a Bowden cable which has a much smoother movement due to its flexibility.

My worry is that can it take the strain of the rudder/elevator. As its a scale model it will not require vast movement of the control surfaces anyway.

Thanks

[Keith Berriman]

I would be dubious of a Bowden cable it is okay in the pull mode but no good as a push mode unless the bends are fixed rigidly and you solder the cable into a rigid state when outside the inner cable . My first model gave me this experience

[Eric Robson]

Hi Russ, my latest model is a 65" M.E.109 built from the Cambrian kit. Bowden cable was included in the kit for the elevator which pushes up and pulls down. I was a little apprehensive of this, however it works well the main thing is to keep the exit as short as possible both ends to stop it flexing and have the outer well supported through the fuselage. Hope this helps.

Eric r.

Is this the CAP kit ?

[Nigel R]

Try the Sullivan red snakes, they are more flexible than the blue type. A bowden cable will also be fine.

Both will need you to make sure the "free" portion of flexible cable (or snake inner) is as short as possible.

This may actually be easier to achieve with the Sullivan red snake, as the threaded rod reinforces the free section of snake inner.

Mind you as RC Plane Flyer says you can use solder to stiffen up the bowden cable a bit.

Personally, I like the Sullivan snakes a lot.

[Russ P]

This is a Cap kit, no instructions other than some notes on the plan, so some thought is required before cutting and glueing. So it's only when building is nearly completed you find where you went wrong. Hence the snake runs etc.

I have always only used Sullivan snakes and will always do so unless needs must.

Thanks for your replies, will give the Bowden a go. Can always remove it a and install the red Sullivan if I can get them.

Cheers

[Bob Cotsford]

When the CAP kits were made (1970's) lightweight bowden cable was quite popular as Sullivan snakes weren't really known to most. The problem with Bowden cable is that it can produce a lot of slop and friction in controls, at least by modern standards. I had a CAP gladiator once - very briefly - but can't remember what I used on the elevators. I have a feeling it was balsa pushrods with the usual bike spoke threaded rods.

[Nigel R]

Having had a look here, it looks like the main problem would be the wide rear fuselage?

**LINK**

Looks like the fuselage is mostly stringers at the back, so you have some access to the internals?

If I had the option I would consider using a red snake for each side - presuming the elevators are not joined.

[Martin Harris - Moderator]

Could you arrange a closed loop Bowden cable system?

[Russ P]

That's the kit. I bought it from a fellow club member for £30, inc laser cut, wood pack, canopy, cowl. So mustn't grumble. It's produce by Sarik now.

thanks to everyone for your comments.

[Eric Robson]

This is one from a CAP plan much modified The cowl and canopy were from Brian Taylor, the wings were from a model kit which was out in the 70's. It was called a Hawk Moth loosely looking like a Tiger Moth. the wings were foam veneer and swept back after a crash the fuselage was fuel soaked the wings were slightly damaged. I cut out the centre section and made a built up one also rounding the tips. It flew very well but at the time I had problems with my eyes and again I piled it in. I had my eyes operated on 20 yrs ago and they have been good ever since, still manage the odd crash. I would like to build another but at the moment I am busy with a Hawker Fury biplane.

[Russ P]

Looks good. How did it fly?

[Eric Robson]

Hi Russ, as I said in the text it flew very well. the mods to the wing worked ok it was fairly aerobatic and quite stable. I have the plans for the Brian Taylor version which is true scale though more complex than the CAP one. Some day if I live that long I may build another with electric power.