Ken Allen offering glass/carbon tubes

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2009 Archived News by Planet News

Wednesday, February 18, 2009

WORLD WIDE WEB — Ken Allen of Performance Hobbies is now offering carbon fiber and fiberglass reinforced phenolic and kraft cardboard airframe tubes in a variety of sizes. Allen is using two wraps of six ounce cloth, finishing the exterior to a smooth, ready to prime surface.

He is using both kraft cardboard and phenolic tubing, available in sizes that will fit industry standard nosecones, with cardboard tubes from 4 inches to 9.25 inches, while the phenolic tubes come in sizes from 4 inches to 11.67 inches. Orders are filled in two weeks turn around.

Pricing:

Fiberglass wrapped cardboard

4" x 48":........$ 65.00 each
5.5" x 48":.....$ 90.00 each
7.5" x 48":.....$110.00 each
9.25" x 48":...$120.00 each

Carbon fiber wrapped cardboard

4" x 48":.......$105.00 each
5.5" x 48":....$120.00 each
7.5" x 48":....$140.00 each
9.25" x 48":..$160.00 each

Fiberglass wrapped phenolic

4" x 48":........$ 80.00 each
6.125" x 48":..$100.00 each
7.5" x 48":.....$120.00 each
11.67" x 48":..$150.00 each

Carbon fiber wrapped phenolic

4" x 48":........$115.00 each
6.125" x 48":..$135.00 each
7.5" x 48":.....$150.00 each
11.67" x 48":..$200.00 each

Allen also specified he would be making custom transitions and boattails as well, with a four week turn around time.

Performance Hobbies
Phone: (202) 723-8257
Website: http://www.performancehobbies.com/

Reader comments:

#1 Re: Article: Ken Allen offering glass/carbon tubes

What advantage is there in using Phenolic vs. Cardboard (or vice versa)?

From my vantage I would predict (and likely be wrong) that the tubes would compare as follows:

Cardboard w/Fiberglass:
Heavier
More Flexible
Less prone to Internal Damage.

Phenolic w/Fiberglass:
Lighter
Less Flexible
More prone to Internal Damage

I am unclear which one would be stronger. I'm also unclear if Phenolic would be more susceptible to separation of the fiberglass and tube due to lower permeability of the tube to the epoxy. (Is that even true? I'm assuming the glassine coating (if any) is removed from the cardboard tube.)

UncleVanya on 02-18-2009 01:58 PM

#2 Re: Article: Ken Allen offering glass/carbon tubes

Hmm Kraft to me means "paper" more than cardboard, that would be your normal kraft airframes which are technically cardboard but hardly resemble the cheap stuff that posters get mailed in.

With a good layup, it shouldn't matter all that much what the core is - the composite matrix brings most of the strength and physical properties. You would want to go with the lightest core material. Wouldn't this be the case?

These prices seem pretty good to me. Two of those 4 inch CF sections would make a nice rocket!

New Ocean on 02-18-2009 04:58 PM

#3 Re: Article: Ken Allen offering glass/carbon tubes

The paper tubes are identical to the heavy paper tubes from LOC/precision. What I like about them is that they are far more accepting to the epoxy resin compared to the phenolic. However, they have more flex in them versus the phenolic, which is usually stiffer. The phenolic, however, because of its brittle nature, can still crack on a hard landing, even with a fiberglass shell; but when this happens, the fiberglass usually holds up, but the phenolic may chip away from the inside, leaving a potential gap in your airframe where there is just the wraps of fiberglass/carbon, whereas the more flexible paper tubes will bend more and absorb that shock.

Also, Id have to check, but I dont think phenolic would have much weight saving benefits over the paper. According to rocksim, a 4" section both 48" long, the paper wins by about 20 grams, but that could easily be off or varying with each airframe size. When I can verify, Ill let you know.

As for benefits:

Phenolic: Much stiffer, uses less epoxy (airframe wont soak up as much), *can be stronger (*not confirmed, need to do some tests)
Paper: Flexible, less prone to damage

Some like to work with one type while some prefer the other.

lkal32 on 02-18-2009 05:05 PM

#4 Re: Article: Ken Allen offering glass/carbon tubes

From what little experience I have with PML's phenolic tubes I'd think it's plenty absorbent to get a good bond.

The advantage I see in a phenolic core is that it's less likely to swell and bind in high humidity and won't "ball up" like paper if it does.

Sono_6 on 02-19-2009 07:55 AM

#5 Re: Article: Ken Allen offering glass/carbon tubes

Do you think the paper will soak epoxy all the way through to the inside?

New Ocean on 02-19-2009 10:58 AM

#6 Re: Article: Ken Allen offering glass/carbon tubes

Quote:

Do you think the paper will soak epoxy all the way through to the inside?

No the epoxy doesnt soak completely through, but it does absorb more than the phenolic. The paper tubes are stripped of their glassine layer while the phenolic can only be sanded with a low grit sandpaper to promote adhesion.

Quote:

Those are also good points. The phenolic definitely does have good adhesion, thats nothing to worry about, but personally, I feel the paper does a better job at it. I do agree with you and phenolic can be more user friendly to work with, especially with cutting and sanding because it wont fluff up like the paper sometimes can. I usually solve that by adding a few drops of thin CA before making the cut, etc.

lkal32 on 02-19-2009 11:04 AM

#7 Re: Article: Ken Allen offering glass/carbon tubes

I was not really thinking about cut edges, but that is a good point too.

Taking a 'paper' rocket to Carolina in the summer has resulted in stuck couplers for me in the past...

Sono_6 on 02-19-2009 11:17 AM

#8 Re: Article: Ken Allen offering glass/carbon tubes

Quote:

I was not really thinking about cut edges, but that is a good point too.

Taking a 'paper' rocket to Carolina in the summer has resulted in stuck couplers for me in the past...

LOL - I live here and while it's a challenge my bigger challenge is winter with various components with all kinds of different expansion rates (quantum, phenolic, paper).

UncleVanya on 02-19-2009 11:25 AM

#9 Re: Article: Ken Allen offering glass/carbon tubes

Quote:

I was not really thinking about cut edges, but that is a good point too.

Taking a 'paper' rocket to Carolina in the summer has resulted in stuck couplers for me in the past...

Oh, I actually havent had that happen to me, yet at least. Id agree with Brad, worst problem I see is swelling of Quantum Tube components...

lkal32 on 02-19-2009 11:37 AM

#10 Re: Article: Ken Allen offering glass/carbon tubes

But since we aren't discussing Quantum tube with regard to these reinforced tubes, it's important to focus on the issues here, right?

Phenolic also gives you the use of a stronger coupler and often it's not possible to use phenolic couplers with cardboard tubes, due to the difference is diameters and thicknesses. Also I think you would be unlikely to prove in real time the difference in adhesion between a properly laminated cardboard tube and its phenolic counterpart.