Tangible Benefits from Glassing Phenolic Tubes?

[SDramstad]

Interesting idea. How many layers did it take to make a tube sturdy enough for an M motor?

I did 5 of carbon and that was overkill. 6 oz "E-glass" fiberglass cloth would probably work well for a level 3 build with 5 layers. Would recommend starting with that instead of carbon as it is easier to work with.

 

[David Schwantz]

Ok Mike, I have now abandoned the 5.5" Mercury Redstone project and just started printing one for the LOC 7.5" tube. Ha!!!

 

[Pem Tech]

Phenolic is as brittle as glass. Not fiberglass but window glass. You don't want to use it unless you are going to wrap it in fiberglass or carbon fiber. No matter what ANYONE tells you, if you dont it WILL eventually crack. in my opinion it's garbage and not worth the time, I would just bite the bullet and get glass tubes.

I do agree with this for the most part. Plain phenolic is brittle, which I discovered first hand. While having never glassed a phenolic tube it has to be extremely resilient. Flexible phenolic has a good rep for strength without glassing, but I have no experience with that product. Anyway, after the naked phenolic debacle we switched to straight paper tubing and are really happy with it.

 

[SnapRoll]

How does the Mac Performance phenolic stack up to the other brands? I've really been eyeballing their VTS-6 kit, but man I get the heebie jeebies thinking about having to glass that kit, as somebody that's never done it before.

-Hans

No need. The Canvas is GREAT stuff. I’ve had it well past Mach, no issues.

 

[Travis NTexas]

Bumping an old thread, but just wanted to say thanks. Just the info I needed, and much appreciated!

 

[lr64]

People are talking almost as if phenolic is phenolic. Well, no. It's just a resin, and I'd guess there are many flavors of that resin. Furthermore, I know that phenolic composites come with at least 4 different kinds of reinforcing fibers. The ones I know about are paper, linen, cotton, and fiberglass. Presumably, there are others.

I also hear people talking about how much of what kind of stuff is sufficient for a level I, II, or III rocket, as if each level are all to the same design, go the same speed, etc. Design details matter, and material type cannot be used as a magic amulet. I could design you a carbon fiber composite rocket that would be guaranteed to break when using only a D engine. A shredding MMX in carbon might be a challenge, but possibly doable*. And I'm sure someone else with the pertinent expertise can design something in cardboard, paper and lumberyard wood that could withstand Mach 3**, though I'd guess for repeat use it might be wise to use something a bit more heat resistant on part of the nose cone and the leading edges. And the rocket nozzle, of course. Maybe paper phenolic?

I'm sure the material requirements for that gigantic Mars Lander enlargement someone made are far different than for something intended to get to 30,000 feet at Mach 3.

Ordinary materials with good design would be superior to just throwing G10 and carbon fiber at the problem.

Even for high altitude, a slow burner that remains subsonic can use THICK foils on the fins without a significant drag penalty. Like, 15 percent thick. If built with patience and a laminar section, these fins could be lower drag than almost all of the other fins you'd see, at least until the first bug splat or unrepaired ding. And certainly lighter and stiffer than solid aluminum or G10.

I am not a big rocket guy, but I've been interested in the engineering problems since I started looking into new fuel for Jetex and reading rocket forums. I have a background in mechanical engineering, have built several small, crude boats, and a variety of model airplanes, so I'm not completely ignorant.

*Especially if made from so-called carbon fiber veil and cheap epoxy.

**I'm sure I could design one for Mach 0.5

 

[SolarYellow]

People are talking almost as if phenolic is phenolic. Well, no. It's just a resin, and I'd guess there are many flavors of that resin. Furthermore, I know that phenolic composites come with at least 4 different kinds of reinforcing fibers. The ones I know about are paper, linen, cotton, and fiberglass. Presumably, there are others.

You're right, phenolic is a category of resins. Countless variations have been used in industry for well over a century.

Most brake pads are held together with some variety of phenolic. Yes, that gets uber-specialized and is pretty much a dark art.

 

[lr64]

So we should buy brake pads and turn them into rocket nozzles? ;-)

Anyway, I'd guess that constitutes a fifth type of reinforcing fiber, whatever it is they use.

 

[Art Upton]

So we should buy brake pads and turn them into rocket nozzles? ;-)

Anyway, I'd guess that constitutes a fifth type of reinforcing fiber, whatever it is they use.

in the old car days it was "Asbestos" fiber

 

[lr64]

I wasn't going to mention that.

 

[SolarYellow]

These days, it's typically a combination of aramid and often refractory ceramic fiber. The advent of aramid pulp on industrial scale in the 1980s was the key enabling tech that really enabled the automotive industry to get away from asbestos. Other details were improved across the board, but that was the one that really opened the door.

 

[JohnCoker]

Phenolic is as brittle as glass.

There are several different kinds of phenolic.
https://www.jcrocket.com/body-tubes.shtml

PML popularized phenolic tubes (competing with Loc/Precision's cardboard). Now there are several alternatives, including GiantLeap and BlueTube. Phenolic is still my go-to material for body tubes, but I generally avoid PML.

 

[thzero]

There are several different kinds of phenolic.
https://www.jcrocket.com/body-tubes.shtml

PML popularized phenolic tubes (competing with Loc/Precision's cardboard). Now there are several alternatives, including GiantLeap and BlueTube. Phenolic is still my go-to material for body tubes, but I generally avoid PML.

And now PML is owned by Loc.