Carbon Rod Wing Joiner On Spirit Elite ARF?

[Aientonni]

Has anyone replaced the 7mm metal wing joiner on a Spirit Elite ARF with an equivalent sized carbon rod. I was wondering how it would change the flight characteristics and the strength of the wing.

If it's favorable...where's the best place to purchase carbon rods. Thanks.

[Ricardo RW]

A friend of mine replaced the metal bar with a carbon rod, it worked out OK, and I'm planning to do the same thing as I get a carbon bar, difficult to find in my country and expensive to import it.

Regards.

[webbsolution]

A friend of mine replaced the metal bar with a carbon rod, it worked out OK, and I'm planning to do the same thing as I get a carbon bar, difficult to find in my country and expensive to import it.

Regards.

There is a fairly decent thread on this topic do a search for "beefy wing joiner for spirit"

My take away on this for a short read is , you can improve the wing joiner but be careful not to make it too strong. In a mild crash or significant nose in landing you want the joiner to fail and not the wing....the stock joiner may have recently failed you but your wing was in tact. Beef it up and your next rough landing will send you home considering a significant repair.

[prodjx]

Aientonni, get a thin wall tube with an O.D. of 7mm. Try to find some carbon tow, Make the tube the length you need, make the tow strand's 2 1/5 time's the length of the tube, wet them out with your favorite epoxy, get some wire longer than the tube put it at mid point of the tow, fold the tow over the wire then fold the wire in half and then pull the tow through the tube, wait 24hr's and youve got a 7mm carbon spar.
You want to be sure you use enough tow so even with the resin the tow doesn't pull through the tube too easily. I used mine to replace a bent metal one and it was alot stronger, ask me how I know. Dave.

[Ricardo RW]

Aientonni, get a thin wall tube with an O.D. of 7mm. Try to find some carbon tow, Make the tube the length you need, make the tow strand's 2 1/5 time's the length of the tube, wet them out with your favorite epoxy, get some wire longer than the tube put it at mid point of the tow, fold the tow over the wire then fold the wire in half and then pull the tow through the tube, wait 24hr's and youve got a 7mm carbon spar.
You want to be sure you use enough tow so even with the resin the tow doesn't pull through the tube too easily. I used mine to replace a bent metal one and it was alot stronger, ask me how I know. Dave.

Thank you for this idea!

I have a carbon arrow shaft that fits the joiner, and will fill the core this way as I have some carbon tow in stock.

Great!

[lsf810]

I bent the 7mm steel rod in my Spirit Elite ARF and found a rod made out of 1/4 in music wire covered with heat shrink tubing an acceptable replacement.

[prodjx]

Isf810, I'd be carefull on launch with that music wire/heat shrink combo, if your using a winch I'd be doing some tapping.
I've never really liked the Spirit 2m laminated aluminum/wood spar joiner, I seem to remember trying to do a ping off a high start in windy condition's and folding the wing.
A few year's later I made an aluminum spar joiner out of some a/c grade aluminum and was able to do full pedal to the metal winch launches with a ping on the end sucessfully it was definately worth the effort. Dave.

[Resurgam]

One problem with pure carbon wing rods is that they do not fail gracefully - an overstressed metal rod will bend, but carbon will just snap, usually with catastrophic results. Also carbon is more prone to damage from scratches and nicks, which cause stress risers, which make catastrophic failure more likely. Carbon inside a metal outer shell (tube) is a good compromise.

[tnavressdog]

I used mine to replace a bent metal one and it was alot stronger, ask me how I know. Dave.


So Dave... how do you know =).

[prodjx]

Tnavressdog, since you asked, I had 2 model's on the same JR 622 and I would use the upper r/h lever to switch from conventional r/e to V-tail that's how I bent the metal wing rod, and sad to say I did it more than once, 2 more time's and I would've been an ace. Nytol, Dave.