Fiberglass vs Bluetube (L1/L2 Rocket)

I did my L1 and L2 with the same 3" Bluetube rocket. I used an H on the L1 and a J on the L2. The L2 was a somewhat different rocket because I added an avionics bay, a payload section, and some weight in the nose, all of which were necessary to move the CG forward with the added weight of the J motor. Having said that, I build a lot more fiberglass rockets than Bluetube. Fiberglass is just more durable.

Joe

Don't forget to look at MAC Performance Rocketry for their canvas phenolic airframes and fin stock. Lots of feedback on TRF for durability and quality.

Jmhepworth said:

I did my L1 and L2 with the same 3" Bluetube rocket. I used an H on the L1 and a J on the L2. The L2 was a somewhat different rocket because I added an avionics bay, a payload section, and some weight in the nose, all of which were necessary to move the CG forward with the added weight of the J motor. Having said that, I build a lot more fiberglass rockets than Bluetube. Fiberglass is just more durable.

Joe

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Just curious, do you fly that rocket on mostly L2 motors now? Js & Ks?

Steve Shannon said:

Don't forget about Quantum Tube from Public Missiles. Just be sure to sand it aggressively before applying epoxy and don't count on it for supersonic flights, but it's easy to work with, has no spirals, and isn't terribly expensive or dense. For L1 or L2 rockets it can work just fine.


Steve Shannon

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Yuch. Quantum Tube (ie, plastic) is mostly forgotten. Too many cons and not enough pros. Even PML themselves is now pushing carbon fiber.

For inexpensive, I would rather work with cardboard. Keep in mind that not all cardboard is created equal. 1.6" and 2.2" is very thick-walled and durable. 2.6" and 4.0" are thin-walled not as durable.

Buckeye said:

Yuch. Quantum Tube (ie, plastic) is mostly forgotten. To many cons and not enough pros. Even PML themselves is now pushing carbon fiber.

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I won't argue about Quantum tubing, but I have a PML Callisto that has been flying for 14 years and the only problem I had with the Quantum tubing was I broke the tube a couple of inches above the fwd CR when landing on a 26 degree day during a winter flight about 7 years ago. I don't think that Quantum tubing is a bad choice, it just has to be used in the right way.

Handeman said:

I won't argue about Quantum tubing, but I have a PML Callisto that has been flying for 14 years and the only problem I had with the Quantum tubing was I broke the tube a couple of inches above the fwd CR when landing on a 26 degree day during a winter flight about 7 years ago. I don't think that Quantum tubing is a bad choice, it just has to be used in the right way.

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This was exactly my experience with a PML Ariel, and it happened 3 times. The fin didn't break, or pop out. The glue joint didn't fail. The body tube cracked, propagating from the fin root. Stock chute was used, but the frail QT probably demands are larger chute on most surfaces.

I've had Quantum Tube rockets do core samples in hard ground and and be pulled and reused. I've also had cracks run right up the sides after a landing on the same ground under chute. If you have a stress riser at the edge of a fin slot, I think it will do poorly.
I flew a Quantum Tube PML Explorer at or over Mach several times. The G10 fins started cracking at the rear right where the passes through the BT, but the Quantum Tube still held up. I ended up retiring that rocket as a result.
I disagree that the cons outweigh the benefits; it all depends on what you expect the rocket to do. For a beginner who wants to fly a rocket at less near Mach velocities I really like the PML Quantum Tube kits. The assembly instructions are very clear and well illustrated and teach a beginner good techniques which can then be applied to other rockets. The worst con in my opinion is that it's not as predictable in how it will react some stresses. The kicker for me was the time the body tube had a crack that ran up the side, not from a fin slot, but from an apparent strike on a small sharp stone on the ground.
I guess I would put it this way. It's possible to build and fly rockets for years using Quantum Tube with no problems as long as you're not pushing things, but it's also very easy to outgrow the limitations of Quantum Tube. For passing a person's Level 1 and 2 flights a four inch Quantum Tube rocket can be just the ticket.


Steve Shannon

I agree with Steve, QT can be a very good material and PML makes some great kits with QT, but you do need to know the limitations.

checked02 said:

Hi, I'm planning on building my L1/L2 rocket over the summer and launching. I'm looking to build a durable rocket which will hold up over multiple launches.

I've been deciding what to build the airframe out of, and I've narrowed down my choices to Bluetube and Fiberglass. Fiberglass would be ideal (more aesthetically pleasing/durable) but Bluetube is cheaper.

What would you all recommend?

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To get back to the OPs question, I would NOT build a single rocket for L1 and L2, unless you plan to use it for only one of those levels afterwards. If you want a L1 rocket, build a 2.6" or 3" with Bluetube at about 4 - 6 lbs and a 38mm MMT. You can still fly it on baby J motors for your cert and on calm days. If you really want a L2 rocket, build a fiberglass 4" with DD and a 54mm MMT at about 8 - 12 lbs. Adapt down to a large I for your L1 cert and then have fun with big J and K motors. The problem is you really can't build a rocket that will fly "well" on that full range of H to baby L. They tend to be too heavy for the small H motors and fly too high on the larger motors.