Composite tubing?

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DynaSoar

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Anyone know of a good cheap source for carbon composite tubing? I'm looking for airframe for a 38mm minimum diameter bird, say 4 to 6 feet of it. Max OD of 1.67".
 
Originally posted by DynaSoar
Anyone know of a good cheap source for carbon composite tubing? I'm looking for airframe for a 38mm minimum diameter bird, say 4 to 6 feet of it. Max OD of 1.67".

Cheap is a word generally not associated with carbon composite tubing.
 
you could contact Wildman Rocketry . I know they have carbon fiber as well as fiberglass tubes (I was eyeing the 38mm CF tube....) Not sure how much they cost, it is not listed on their website. Working off memory, I think it was ~$50 for a 4 or 5 foot section (although I could be pretty far off).
 
Originally posted by shockwaveriderz
https://www.macqc.com/tubing.php

check their stock sizes....

A couple of the 26.4" bicycle down tubes would be perfect. but.
ID is 1.5" exactly. All the 38mm airframes I've checked are 1.525". I'm afraid that 25 thousanths is going to make the difference between the motor going in or not. Looks like I'll have that same problem with any "standard" 1.5" tubing.

I wonder how hard this stuff is to sand?
 
You really don't want to sand CF tubing. If you do, one, it gets fuzzy and two, when it gets fuzzy it means you hit the carbon fibers and then are destroying the laminate that gives it the strength.

Edward
 
Also, from my experiences with CF, it will create little splinters that hurt like heck for a week if you touch them. It hurts, it had it happen to me 3 or 4 times before i found out what was causing me to swear so much.
 
35072 FW-1.5x1.6 1.53 ID 1.63 OD .050 .167 14’ on-going fw smooth $17.55/ft.
 
Originally posted by Elapid
35072 FW-1.5x1.6 1.53 ID 1.63 OD .050 .167 14’ on-going fw smooth $17.55/ft.

Great diameter, but it comes in 14 foot length. That's almost $250 worth of tube. Now, if I knew 3 other people that wanted 42 inches each.....
 
DynaSoar -

With our 2" carbon sleevings you can easily make your own carbon fiber tubing at a significant saving over pre-bought tubes.

Plus when the 2" is used at 1.5"/38mm diameter, the change in yield of the sleeve is 20%, meaning you get 20% more useable sleeve when used at 38mm.

Depending on how much strength you desire, you can use 1 layer over a paper Loc style tube and have a very strong tube. Or use a properly prepared mandrel (all contained in our tutorial btw) to make a stiff and sturdy tube. Using 2 layers of carbon results in outstanding carbon tubing, or use a layer of carbon sleeve, plus a layer of fiberglass sleeve to save even more on cost.

Plus right now if you order 5 yards or more, not only do you get a 5% discount but a free yard of 4" fiberglass sleeving.

Nick Anderson
https://www.aerosleeves.com
 
how does it compare with pre-fab tubing from a cost per foot standpoint after all the supplies are purchased and construction time considered?

how much will it cost me to make a 3' tube compared to the $53.00 (est) commercially available tube, and how will it compare structurally?

if it's a lot cheaper, or structurally superior, i'm on board!
 
Originally posted by Elapid
how does it compare with pre-fab tubing from a cost per foot standpoint after all the supplies are purchased and construction time considered?

The cost is most likely similar, but may be higher or lower in some cases. Most commerical carbon tubing compaines are dealing with thousands of feet of tubing, and thus benefit from the mass market manufacturing techniques. However our product gives you a choice on how you to fullfill your tubing needs. If your concerned about the mass of the tube, or the strength of the tube you can ultizae different amounts of carbon and other materials to fit your needs exactly. I.e you can custom fit each tube/rocket airframe to your needs. Need to go mach 4 and 30,000 ft, Aerosleeve tubing can do that. Need to be comparable in weight to standard paper/LOC style tubing, but have much more stregnth (especially in the key direction, compression)
Originally posted by Elapid

how much will it cost me to make a 3' tube compared to the $53.00 (est) commercially available tube, and how will it compare structurally?

if it's a lot cheaper, or structurally superior, i'm on board!

It depends on how many layers of Aerosleeves you intend to use, what core material (if any) and if you plan to laminate or create full compoiste tubing.

1 yard of 2.5 " carbon (which will fit on 3" tubes with a 25% decrease in length) is $23.39.

1 yard of 3" fiberglass $12.99

You can figure out the price of the tube you want to create.. Ad $1-2 per foot for epoxy.

I dislike recommending that you ever make a tube from one material. When you combine materials (and hence a composite within a composite) you will come out with a better result. Oblivosuly using a core material (honeycomb, Baltek/Coremat) or similar will result in the best end result, but this is difficult to do. You can intimate using a "true" core material with the use of fiberglass.. Fiberglass is alright as a tubing material by itself, but even better when pared with carbon. The carbon gives the laminate is stiffness and some strength, the fiberglass gives a lot more stregth and lets you ultize the carbon where it will be ultized the most, on the outside of the tube where the forces associated with loading are most pronounced. Think about why I -beams are better than straight beams..

Also, a inner layer of paper tubing is an excellent choice, especially for min diameter applications. The paper provides a lot of stiffness, plus a good amount of thermal insulation, important for long burning motors.

Also, don't ever confuse "stiffness" with strengh. Even because you maybe be able to "squeeze" the end of the tube, this does not mean the tube is "weak" and not strong. I've seen many rockets fly with tubes you can ovalize by squeezing fairly lightly. They've all held up during flight and even more impact prone landing. I'd rather have a tube that flexes some during loading, than one that will simply shatter when loaded in excess. (phenolic) Also, how many times do rockets ever enconter "squeezing forces" on the airframe ? Pretty much never. Its all compression and some torsion.

I've personally crashed a number of rockets that used composite airframes, some with aerosleeves. The amount of damage sustained by the airframe is almost always never. Likewise, how many phenolic/fillamentwound/paper just shatter on impact ? If you increase the time of impact, your overall loading force goes way down.. Cars are made with crumple zones and airbags for exactly that reason.. Rockets are starting to ultize the same ideas.

Nick Anderson
https://www.aerosleeves.com
 
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