clemsparks

I'm cleaning up and "rebuilding" an old cox engine with the aluminum tank/mount. I don't seem to find any of the nylon tubing for a pickup around here. I was wondering, if I can't find some, how about using some small silicone tubing with a piece of light safety wire around it to mold it into the necessary shape. Sounds like a good idea to me, but wanted to know if anybody had any reasons not to do it.

Also, any hints on where to find the small size nylon tubing? The mega-stores (HD and Lowes) don't have them. I might have to scour some other places.

Thanks,
Clem

jboy381-RCU

i'm glad you posted this...i need some to go in a dragonfly fuel tank(it has a clunk)...the tube in the tank was dry rotted and i need to replace it...1/2A tube won't bend to the bottom of the tank...


guys help us out please...

john

DICKEYBIRD

Clem, the tubing is some kind of clear vinyl-like tubing. Hobby shops used to carry it under the "Perfect" brand. Haven't seen a lot of the stuff lately. It always turns rock hard and starts to leak air. I like to make my own from 3/32" aluminum tubing bent into shape with a Higley bender. A short piece of small silicone tubing attaches that to the nipple. (Pic attached)

Back in our local u/c sport racin' days, great pains were taken to shape the tube to it's smallest possible length with the end shaped VERY carefully to ensure every that every drop of fuel was picked up. (Had to get as many laps as possible!)

John, the quest for very small, flexible silicone tubing for 1/2A clunks is frustrating for me! I hope that one of these days somebody on the forum will get a giant roll and sell lengths of it to all of us. The best I ever had was some kind of dialysis machine tubing a friend gave me.

Tim Wiltse-RCU

John,

You asked me about the small silicone tubing didn't you? I'm sorry I forgot to answer you ....I have bought it from a local shop. I'll try to get my butt down there this weekend and get a whole bunch as I need some too. I'll see if I can score a roll of it!!!!

Later,
Tim

ajcoholic

My Feedback: (10)

I have some micro sized surgical tubing that I bought from Kuston Kraftsmanship at least 10 years ago, for use in the 1/2A cut offs (for free flight timers). It works double duty as an extremely flexible clunk line (I used that in my custom 020 tee dee tankmount) and I have a few feet left. I can definitely spare a few inch long segments for those like Jboy needing a replacement for the dragonfly tanks.

As for the inside of the cox tanks, what aout using some Robart retract air tubing? It can be heated and shaped intoa tight curve and it strong. I use it for lines from the tank to carb for the teedee 010 up to 049 on the tankmounts. I have used it inside reeders too...

I also have used some hard plastic line also shaped with heat tofit, and it worked well. Trouble is I get this stuff places a bot at a time and it works out but I forget where it came from! [X(]
AJC

clemsparks

Cool,

I actually had that idea, too. Nice to see it in the photos! I'll see what I can figure out.

Seems to me that a smaller diameter would allow for better draw, as long as it's not so small as to restrict flow. Anybody know what the breakover point is on that one? What's the optimum diameter for draw/flow/weight?

Thanks,
Clem

DICKEYBIRD

Actually, the ID of the aluminum tubing is pretty close to the original clear tubing. When you factor in the restriction of that little spring inside the orig., the alum tube is probably better. No big deal as either will flow far more than is needed to run properly.

clemsparks

I still like the aluminum idea, but then I remembered I need to do one for an .020 as well. Not sure if I can bend a piece of aluminum tube that tight, but I may give it a go.

Thanks,
Clem

ballgunner

My Feedback: (1)

Dubro also has a very good tube bender. For me it works better on small bends than the Higley although I have and use both.

jboy381-RCU

tim,
i forgot about that myself...but if your going there pick me up about a foot...i guess they sell it by the foot...let me know the cost,and i'll send a buck or two...

AJ,
thinks for the thought, but tim is a little closer than canada...keep me in mind tho...if tims stuff doesn't work...i'll get a couple of inches from ya...

thanks,
john

BMatthews

AJ, I'm surprised at you suggesting the latex cut off tubing for the fuel tanks. That stuff goes all gooey in no time around fuel. Certainly it would dissolve faster than the vinyl goes hard. I use it on my free flight power models and it lasts for a few months at best.

I guess I'm lucky as the LHS has always had rolls of the small silicone tubing. I'm talking the stuff that's about 1/8 OD and 1/16 ID by Sullivan.

ajcoholic

My Feedback: (10)

Bruce,
Why are you surprised? Its been the ONLY small, flexible tubing that will actually move around in a small tank such as the Dragonfly. I didnt suggest it for Cox hard tanks (babe bee style) but for the clunk tanks.

What else will move so freely with a 1/2gram clunk on it? Let me know and I too will use it.....

Besides, I have some pacifyer tanks I use to run pressure engines on my test stand that have lasted for years. I think I'll get more than a few months out of it, but we'll see. In my 020 tank on my little stick, I can unscrew the backplate to access the tank interior. I flew it Jan 2nd, and this spring when I start flying again, I will check it out.

That Viton stuff might be the ticket, but it has to be as flexable as a piece of overcooked spaghettini to actually work with that tiny clunk, in that small of a tank...

AJC

ajcoholic

My Feedback: (10)

I have a mess of that stuff. Its absolutely no good for a clunk line, with my tiny clunk, when the line is 3/4" long and expected to mive freely up and down inside the tank which is 7/8" diameter inside.

AJC

BMatthews

DOH! ! !

I didn't realize that the Dragonfly uses a clunk system. In that you're very right that the thin latex would be darn near the only option for such a short line and light clunk weight. My booboo.

ajcoholic

My Feedback: (10)

If you DO find an alternative... let me know about it!

That Viton stuff, is it flexible?? Larry?? Are you listening...

AJC