body tubes question

[bachsta]

what is a better body tube to go woth for durability a quantum airframe form pml or a fiberglassed phenolic body tube?

 

[Justin Horne]

Depends on what you are doing. Simply put, generally, fiberglass phen. is stronger. Having said that, quantum is better for going less than 85% of mach, and stuff like general flying. having said THAT, glassed phenolic is actually a tad better even for that, but the extra strength isn't worth the work, time, and money involved in it... Simply put- general flying, quantum, extreme stuff, glassed phenolic.


Hope that wasn't too confusing,
Justin.

 

[stevecarr]

I like Loc tubes for mid power birds.
They are plenty heavy cut easy and a little cheaper than pml or at.
Quantum tube is super easy to finish. Just sand before you glue or paint. No filling!

 

[Ryan S.]

Glassed Phenolic is superior to quantum, paper, phenolic, or glassed paper.

 

[Justin Horne]

Originally posted by Ryan S.
Glassed Phenolic is superior to quantum, paper, phenolic, or glassed paper.

Yes, it is, but for sport flying, I doubt it's worth it.

 

[DynaSoar]

Originally posted by bachsta
what is a better body tube to go woth for durability a quantum airframe form pml or a fiberglassed phenolic body tube?

For durability, a two layer tube with kevlar over glass is best. Glass over anything is more durable than anything without it.

 

[bachsta]

ok just wondering because pml say you can squeeze drop or throw a quantom airframe on the ground and it wont break or crease like paper and phenolic. also what is the strongest body tube material when fiberglassed? and why does fiberglass make things so much stronger?

 

[Justin Horne]

Well, the quantum is strong. However, it is NOT stronger than glassed phenolic, unless it was glassed with a low weight cloth. Generally, the quantum is weaker, but is strong enough...

As I said earlier, unless you are doing some fast, big motor powered flights, the quantum will work for you.
Why is it stronger? well, I think it's because the cloth acts as a binder and stiffener.. Either way, it's rather effective.

 

[DynaSoar]

Originally posted by bachsta
ok just wondering because pml say you can squeeze drop or throw a quantom airframe on the ground and it wont break or crease like paper and phenolic. also what is the strongest body tube material when fiberglassed? and why does fiberglass make things so much stronger?

It's the glass plus epoxy that makes it stronger. Epoxy holds stuff together real well. The more surface glued, the more bond you get. The glass weave or matte provides an enormous amount of surface area, in the form of lots of fibers close together, but with enough space between them for epoxy to flow, so that all the epoxy gets to hold to something. Having this in contact with a surface means having the epoxy glue every bit of the surafce to every other bit into a solid mass. Glass+epoxy on the otuside also makes it much more resistant to impacts and abrasion.

Kevlar is even more resistant to impact and abrasion, but it's a little heavier. Carbon is lighter, but not as resistant. All work on the same principle, epoxy flowing into the weave/fibers. In fact, tubes are made of one or two of these three things together plus epoxy, without being on the surface of an underlying tube at all. Glass plus epoxy is so strong that it doesn't need the tube, so if a tube is there, it's very very strong. Without a tube in there, it's much lighter than with. That's how and why all-glass or carbon birds are made.

The strongest glassed tube would be the tube that was strongest without it, plus the glass+epoxy. I have a feeling that a paper Estes type tube glassed would be stronger than the strongest unglassed tube. That's just a guess though. Quantum might be as strong.

A glassed tube weighs more though. There's a performance/strength trade off. The best policy is probably to figure how how strong you need it to be and go with the lightest tube that's strong enough. There's not much fun in building and flying a rocket that's built like a brick and flies like one.

 

[bachsta]

ok so glassed is stiff but stronger than quantum and quantum is flexible but weaker than glassed?

 

[Missileman]

A testament for QT.
Just this past weekend I flew my PML Amraam 2 at a new launch site.
I have gotten use to landing in soft fields so no thought was given to using a slightly larger chute.
This flight landed squarely in the middle of a paved parking lot, and even bounced!!
I thought sure the BT would be shattered. To my surprise only some minor scratches.
For subsonic flights QT is best.

 

[bachsta]

that sounds like its right along the lines of what pml is saying. thanks

 

[DumasBro2]

I have also seen a QT rocket blown over from the wind and shatter the tube.

-steve

 

[jetra2]

That was likely from it being very cold outside - QT wants to shrink in cold weather, from what I've heard.

Jason

 

[DumasBro2]

Not "very cold" by our standards, around 50 degrees.

 

[bachsta]

id say thats pretty cold but then again i live in southern california