teleflex cables

jany77

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im looking into replace the pushrods with teleflex cables,is anyone has use them before ? id like to hear some pros and cons also locate them would be nice since there is lot of different types and brands on market thank you
 

jcarleto

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I have teleflex cables on the Bulldozer for the push-rods and the rudder. I like them.

Basically, they are more expensive and perhaps a bit heavier unless you under-size them (not a good idea). I think they dampen a bit of the 2-per-rotation effect. They also take the possibility of a control issue from interference from an external source (bird strike, wayward seatbelt end, hair, passenger) out of the equation. I used them primarily to prevent a passenger in the rear seat from grabbing the push-rods in a panic....which would have caused me to panic.

I like Mid-West Controls and used them for both the cyclic control and the rudder cable. They make custom cables pretty much any length and travel you need.

Some people have voiced concern for using push-pull cables in a vertical application. Mid-West told me that wasn't an issue. I use only the stainless cables and hardware.
 

jany77

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teleflex

teleflex

can you recomend the size ,most i saw has 10-32 threaded end which is not enough for rotor head connection thank you
 

Dirtydog

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jany77 : ( Resasi) Used themon his rudder control cable also. But not on the push rods..
Sent you PM
 

jcarleto

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I used 3/8" on the rotor control and 1/4" for my rudder. That is certainly overkill...but I'm an overkill kinda guy. Look at the "Make your own custom cable" wizard on the midwest controls website. If you need a longer travel or other unusual parameters than they list on the wizard, then you have to call them. There are other sources, I am using this as an example.
 

Aussie_Paul

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can you recommend the size, most i saw has 10-32 threaded end which is not enough for rotor head connection thank you
I used the 10-32 push pull cables on my Firebird for both pitch and roll, BUT I used 2 for pitch and 2 for roll. This gave a totally redundant pitch and roll control system.They were fantastic and could be adjusted to achieve the correct feel in the stick. No slop and I am sure reduced the shake although I used the "magic" bush similar to the RAF BUT had the trim springs pulling down at the rear as per Bensen. This was the best mast and control system I have ever flown and there have been many.

Aussie Paul. :)
 

Semler

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Teleflex Cables are the go, smoothness and zero slop if setup right. but be bloody careful i know of one gyro that was involved in a fatality where it was found after the fact that on this particular gyro that had a electric prerotator system, it's airframe was its earth.
The cluster plates were powder coated and the easiest path for the earth was thru the push/pull cables, Over time when the electric prerotator was under load it would heat up the push/pull cables and over time it tightened the plastic outta to the push/pulls, there was something like 50 pounds of force needed to move it compare the designed 15 pounds of force (Those figures are only guesses as i cannot remember the actual figures.) (Just to add it wasn't the reason it crashed but certainly didn't help things.)

So if i was or if a mate was building a gyro with push/pull cables, I would make sure that they create the control system either isolated from the airframe earth system or do not make the airframe the electrical earth.

So please keep it in mind.
 

RotoPlane

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Like Paul, I like redundancy and adjustability in flight controls and I am going with sealed dual 3/16" Teleflex cables for all flight axis's and one 10-32" mast position feedback cable. Actually, I really don't have any other logical option with my control system.

I never have liked the airframe as a common electrical ground…to many bonding problems over time….couldn't do that regardless 'cause my airframe is glass.
 

Vance

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Musings about push/pull cables.

Musings about push/pull cables.

I have found there are many different manufactures of push-pull cables and the specifications vary widely.

According to the information I have received from the various manufactures of push-pull cables; they are much stronger in pull than push.

The push load capacity goes down as the travel increases blocking the avenue of using mechanical advantage to reduce the load on the cables.

In my experience as the push loads go up the housing compresses slightly making the connection less positive than I would like.

If I were to use them to control the rotorhead I would use two cables for each axis and set them up in a desmodromic way.

Having one cable always in tension would increase the safety load factor and the push cable would still provide redundancy.

I feel that minimizing sharp bends in the cables is important because the drag and compressibility goes up with a bend. I have found most manufactures will provide minimum bend radiuses.

For the electric pre-rotator on the Predator the starter housing is grounded through a large wire directly to the battery ground so that it doesn’t ground through the pitch and roll bearings.

Thank you, Vance
 

NoWingsAttached

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I think I've seen cables used on RAF, Sparrow Hawk, and Magni.

One thing you should NEVER do is install ANY sheathed control cable (throttle, prerotator, etc) in such a manner that the installation allows for a drip loop that can accumulate water. One end of the cable should be a drain for moisture. NO part of the cable should be lower than this end.

If you absolutely MUST have a part of the cable that winds up lower than the lowest end, clear the cable with dry, compressed air periodically to keep it dry inside. You don't want water sitting inside the cable, it will rust out even stainless steel over time.
 
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