Brodhead Pietenpol Association

Sorry if this has already been addressed but I have been unable to find.
Using 1/8" cable for stabilizers but unable to figure out the correct turnbuckle to use.
Here is my guess: AN393 / MS20392-17
Too expensive to guess though.
Thoughts?
Recommendations?

JimBob; using 1/8" cable for the tail brace wires? The breaking strength of that cable, whether 1x19 or 7x19 (1x19 for standing rigging or 7x19 for cables running and flexing over pulleys) is at least 2000 lbs and those wires will never see that. You should consider something a little thinner, perhaps 3/32". In either 7x7 or 7x19, the breaking strength is roughly 1000 lbs and that's a lot of force. Once you determine the cable strength, you can select the turnbuckles to provide equal or better strength than the cable so you don't spend extra money and add extra weight for larger turnbuckles. However, let's hear what others have done.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Understand. The only reason I'm using 1/8" is because thats what I've got. Just trying to save some $$. However, if bigger/stronger turnbuckles cost more to offset the cost of the smaller cable, then....?

Have you considered the weight of the 1/8 cable & turnbuckles compared to 3/32?

Since the tail of the Piet is notoriously heavy, any weight you can drop is rather large in the overall scheme of things.

A few ounces here, a few ounces there, and all of a sudden you've dropped significant weight.

One thing you'll hear over & over is: build it simple & build it light.

Best of luck on your project.

Thanks for the replies/suggestions. I have also noted that the plans call for 14ga hardwire and the manual (same picture) calls for 12ga hardwire.
I had assumed I was going to use cable but is anyone indeed using "hardwire" as per the plans? And if so, which gage and pros and/or cons of going that route. Thanks all.

JimBob; I have no experience working with the hardwire braces so I'll let others chime in on that aspect of it, but one 'pro' of using the hardwire is if you're going for a period look, they look much more like aircraft work from that era. Well-done wire braces with nicely-made wire ferrules look very pleasing to my eye. In the 'cons' department, I'd have to say that adjusting and repairing hard wire braces can be a much more daunting proposition than doing it with conventional nicopressed cables and thimbles. Somewhere in between those two approaches would be using cable but wrapping and then soldering the wraps would make for an early appearance but probably not as difficult as making the hard wire braces and ferrules.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

N34KP has tail brace wires of hard wire with nicropress sleeves and turnbuckles. I'll see if it can find a closer shot.

Well I'll be hornswoggled! I don't think I've ever seen one with nicopressed hard wires! I couldn't tell from the photo, but are the short tails of the wires thenbent back up against the nico sleeve like they are with wire-wound ferrules?

-Oscar

Man, that would have to be pretty thin/small ga in order to do that.

34KP has 12 gauge wire on the tail braces and 11 gauge wire for the center section rack wires. The bends aren't that tight, they bend around the nicropress sleeves.

Well now I can say I've seen hardwire tail braces nicopressed!

-Oscar

Oscar. I did the same thing on my tail hook release.

Richard,

Clever idea on the nicopressed hardwire.

It may be just the perspective of the picture but it appears that the aileron control cable may be touching some of the fabric as it passes up into the wing. If the fabric is ceconite and the cable is touching it, over time the ceconite will eat away at that cable. Clearancing the cable by making the hole slightly larger will avoid that scenario.

Cheers, Ken