RC India

RC Equipments => Tools, Materials and Building Techniques => Topic started by: bokilap on March 24, 2011, 11:50:56 AM

Title: Joiner for cf rods?
Post by: bokilap on March 24, 2011, 11:50:56 AM
Hi guys,

I am currently in the process of making my first plane. Its a 33" blubaby.
I am going with the UC wings. According to the plan it is a two part wing.
It also would have a small dihedral. I was thinking of using cf rods for reinforcement. I was thinking of fixing them on the leading edge and if required also on the trailing edge. Just like how the bamboo sticks are fixed on slowstick wings.

Is my thinking correct? Will this arrangement work? If this has to be done then what should i use as a joiner for the cf rods? It (joiner)would be required to be bent to the angle of dihedral right?, some kind of aluminium tube or something?

Any other idea is welcomed too :)

Plz guide
Title: Re: Joiner for cf rods?
Post by: SunLikeStar on March 24, 2011, 11:53:15 AM
what size cf rod do you have?
Title: Re: Joiner for cf rods?
Post by: bokilap on March 24, 2011, 11:57:41 AM
I dont have them yet but was thinking 2mm or 4mm ?


hehe cool avtar.... the plane should come back and hit him in his head   ;D
Title: Re: Joiner for cf rods?
Post by: SunLikeStar on March 24, 2011, 12:04:44 PM
Get 5mm tube instead, they are lighter and are more rigid. Plus they can be easily joined using motorcycle spoke. Buy the tubes from RCD, they have good quality at decent price.

Quote from: bokilap on March 24, 2011, 11:57:41 AM
hehe cool avtar.... the plane should come back and hit him in his head   ;D
That would be Atul's avatar  :giggle:
Title: Re: Joiner for cf rods?
Post by: ujjwaana on March 24, 2011, 12:06:26 PM
Take the CF rod to A\C fridge repair shop and buy some length of matching Brass tubing they use. The CF Rod should Flush fit inside the Tube. cut a small length of the tube, say 2" and bend it to the Dihedral angle. Insert the CF rods on both side with some epoxy on them. Done.

I would suggest a Solid 4mm CF rods as it is good enough to handle 33" WS.
Title: Re: Joiner for cf rods?
Post by: bokilap on March 24, 2011, 12:15:23 PM
Thanks Ujjwaana!

Its a good idea, will def try that!
Do you have an idea what size brass tubings they use? is it 5mm?
Also, should this arrangement be used for trailing edge too? or not necessary?

Thanks for your inputs  :salute:

Also any other materials for joiners i should look out for ?

Thanks  :thumbsup:
Title: Re: Joiner for cf rods?
Post by: SunLikeStar on March 24, 2011, 12:27:42 PM
Quote from: bokilap on March 24, 2011, 12:15:23 PM
Also any other materials for joiners i should look out for ?
look out for joiner i posted >:(
please read my post also :(
Title: Re: Joiner for cf rods?
Post by: bokilap on March 24, 2011, 12:42:42 PM
Arey amit i did read your post yaar! Thanks for that!

I was looking for a 5mm hollow rod at RCD, they have a 4x3x1000, 3x2x1000, 5x3x1000 hollow rod, will that do?

I have some cycle spokes, can try this idea too

cheers mate! :salute: :thumbsup:
Title: Re: Joiner for cf rods?
Post by: SunLikeStar on March 24, 2011, 12:50:12 PM
5x3x1000 hollow, is what i was talking about. Cycle spokes are 2mm so wont fit in the tube, motorcycle spokes fit perfectly and are pretty strong.
Having said that, ujjwaana's idea is the best one to go ahead with.. i just wanted some attention  ;D
Title: Re: Joiner for cf rods?
Post by: PankajC on March 24, 2011, 01:23:39 PM
Quote from: ujjwaana on March 24, 2011, 12:06:26 PM

I would suggest a Solid 4mm CF rods as it is good enough to handle 33" WS.


Hey, I use 2.5mm solid for WS 42inch without any problem
Title: Re: Joiner for cf rods?
Post by: PankajC on March 24, 2011, 01:27:53 PM
For joining hollow tube, I take a GI wire, apply small quantity of 30min epoxy and then insert into the hole after wrapping little bit of silk thread to increase the thickness. Since I am wrapping it with the epoxy the thread also becomes rigid after curing and the bond is solid
Title: Re: Joiner for cf rods?
Post by: ujjwaana on March 24, 2011, 01:38:03 PM
Even I liked Pankaj idea of hollow tubes and GI wire. As he said he used 2.5mm rod on 42" WS, you can even get a 3mm Solid rod from RCD. I would be a little weary using a Hollow tube for critical place like Wing. Reason being they can develop invisible cracks on the glues side and may fail at times. For few grams more, Soled rod is best choice. You can use hollow tubes in places like Tail/Fin area.