Push-Pull primary controls

splashdown · 17-10-2008, 07:42 PM

I am trying to get in touch with anyone who is using push-pull cables as their primary control system.

If you own such a gyro, or know of someone, could you please respond to this thread, or leave me a PM.

Cheers!

Lloyd

niquenaque · 17-10-2008, 09:48 PM

Lloyd,

They are bowden cables. Jeff Henley-Smith had one on a machine I saw, I think.. maybe have a look at his machines.

There was a fellow named Rob who came to HVGC with one at the strip when it was at Whittingham, but that was 3 years ago, I have no idea where it is now..

Sorry I can't be more informative but it might jog somebody else's memory.

Cheers,

Nic.

almar · 20-10-2008, 02:40 PM

Yes, Jeff H/S fitted them to all of his machines. Where abouts are you located Lloyd?

rotor · 10-11-2008, 02:02 PM

Well I was talking to the Lame that signed my plane off the other day and I happened to ask whether he had had anything to do with gyrocopters .....

His response was that yes had and he had once .. a while back been involved or knew people from the "Rebels" (SEQGC) Gyro Club in Caboolture, and had built a gyro after telling them that he thought he could build a better and safer gyrocopter than what was available - back then (how long back I dont know)

To cut a long story short he said that he was the first to build a control system with the triple Bowden cables. He also said that he was the first to offset the gymble head - back about 3/4 to 1 inch to improve stability .....

Any thoughts people ....

rotor

splashdown · 12-11-2008, 11:41 PM

Sorry for not getting back to you guys. And thanks for the replies.

I knew Jeff HS pretty well, and I am using the same push-pull control cable setup to the one he designed for the Gyroz. Before his untimely departure, Jeff had manufactured my cyclic and also had done the rotorhead mods for the cable control.

The reason I posted was the the source for the push-pull cables Jeff used (Flexible Drive Agencies) suddenly decided they will no longer supply the cables, and I was forced to locate another vendor. I think I have all that sorted out now, so I can get back to finishing this thing.

Almar- I'm in Canberra.

Rotor- You need to be really careful when you have a redundant setup like a third cable. If your angles and push-pull distances at both ends of the control system are not matched perfectly, you can get the system working against itself (either locking up, or eventually breaking something).

I used to have a gyro magazine that had a picture of a french (i think) gyro with a triple cable control system. It was a weird setup. The cables were attached to the ends and the centre of a 12'' rod that was welded to the cyclic about 6 inches in front. The cables went straight down, ,then did a 180 and back up the mast to a similar rod on the rotorhead. This tandem gyro had some other weird "innovations", like 4 individual engines driving a common shaft, and a hollow frame and mast (looked like welded alloy) that was the fuel tank.

Anyway... thanks again

mceagle · 13-11-2008, 07:17 AM

Quote:

He also said that he was the first to offset the gymble head - back about 3/4 to 1 inch to improve stability .....

G'day Geoff. Your LAME friend must be fairly old. Bensen changed from the spindle head to the offset gimbal head in the early sixties and as far as I am aware, all heads (except for the earlier Sportcopter) have been derivitives of the offset gimbal head ever since.

Murray Barker · 13-11-2008, 03:28 PM

I think I may know the person you are referring to. As Tim said I think he may be "bending the truth' a bit. The first gyro I saw with cables was Bill Monczka circa 1989. Another was Charlie Fox's gyro with a triangular torque tube with one cable at each corner, 1993. It was a Trike body modified.

Charlie Fox was a mate of Ken Cole, the original 'inventor" of the "Gyke" (Rotor blade on a Trike A frame control) as he called it. Ten years before Rob Patrony started messing around with them.

By the way,the "Rebels" gyro club was no way connected to the SEQGC,but that's another story......

rotor · 13-11-2008, 07:40 PM

Tim, .... I not saying what he said was correct - I'm just posting what he said and looking for comments. I may have even misconstrued what he said (but I dont think so).....

Murray ..... he didn't mention SEQGC only "Rebels" It was me who put the 2 together - so what is the history of the "Rebels" gyro club, where they the fore-runners of SEQGC ???

rotor

mark horan · 15-11-2008, 10:35 AM

I have an old ted minty "skyhook" gyro in my shed that has quarter inch teleflex, pto or whatever you want to call them contol cables. They are set up as any normal "control tube" system is, ie , as one pulls the other one pushes and even though they are dimentionaly challenged, as some would say, the system works remarkably well, smooth and with out the standard routing challenges that control tube setups present.
My opinion is ,the best push pull cables are made by a company called Morse (sydney I think) in canberra they used to come through tractor replacements, but I think they make their own (tractors) now although I found them to be not as smooth acting as the morse cables (red as opposed to tractors green ones).
Anyhow, I think ASRA dictates that you must use 3/8 or 10mm Cables (big and heavy), I have used 5/16 (which can PUSH around 240 lbs and pull somewhere near double that) to good effect. there seems to be a paranoia in aviation about cable actuated control systems and a requirement to have redundancy in them.
Push pull cables actually have less deflection than control rod systems and fewer moving parts, ie, fewer points for failure. Addmittedly, regular inspection of the cable itself is not possible, but with the cable sealed from dirt and dust they would take an awfully long time to wear out. If the controls started to get a little binding, who wouldnt throw them out and buy a new set? I have seen problems with control tube setups, both in the joystick setup and in over centering hinges halfway up the mast...talk to Ken Watson about the latter!
Push pull cables work really really well in a circuit system and should be treated the same as the "norm"
The other problem with having redundancy is, how do you know when the main unit has actually failed? More weight= flying dreadnaughts...... Ill get of the soapbox now....

Mark.

nickn · 15-11-2008, 03:34 PM

Have a look at www.tuthill.com they are in Melbourme they make push pull cables for race cars, aircraft, boats, machinery, you name it. They have a hole range of products and good service too.Also do good rod ends that are not over the top in price. All the spec sheets are on there web site.