Lightweight Large Diameter Body Tubes

[Bruce]

I was thinking of building a low and slow G powered rocket that would be greater than 4 inches in diameter. But it seems that most large diameter paper tubing of that size is really thick and heavy.

Does anyone have recommendations on relatively thin wall paper body tube larger in diameter than the Semroc BT-101?

 

[James Duffy]

Rolled 1/64" plywood is your friend. One of these days I'll put together a tutorial showing how to create them.

 

[Bruce]

Can you recommend a source for 1/64" plywood that is greater than 12 inches wide? 12 inches rolled makes a tube smaller than 4 inches in diameter.

I'd really prefer a ready made tube rather than a roll your own.

Someone must make thin wall paper tubes greater than 4 inches in diameter?

 

[justforfun]

www.aircraftspruce.com

www.wicksaircraft.com

GLII plywood.

 

[jimzcatz]

https://performancehobbies.com/secure/store.aspx?groupid=72620041122456

 

[burkefj]

The 1/64 I found was about 1.2 oz/sq foot, James is that about what you have found?

 

[Bruce]

Wicks Aircraft appears to have nothing thinner than 1/32" plywood and I'm afraid that shipping will be expensive.

I searched for GLII with no luck.

Performance Hobbies "4.5" dia x 48" long glassein coated cardboard airframe" might be good, but I wonder what the wall thickness is? And 4.5" is only slightly larger than the Semroc BT-101. Is there something larger in the thin wall paper tubing?

 

[bjphoenix]

I have a scratch built rocket with 4" diameter LOC tubing and nose cone. It is relatively short, patterned after the Binder Design Thug. The tubing isn't all that heavy compared to the other parts such as the plywood fins, motor mount and nose cone. A nose cone for say 5.5" tube would be much heavier.
My 4" rocket flies pretty well on a G64, higher than you might think. If you wanted something larger meaning more aerodynamic drag then you could start with a 3" or 4" rocket and start adding on external pods and so forth. I've always been intrigued by clustered body tubes such as the Nike Zeus booster or some of the Saturn 1 boosters. You can get small diameter tubing that is light weight so you could cluster some of those around your G and have a bulky but lightweight rocket. I've been thinking about things like this because I've been wanting to do a similar thing to an Estes Lil Bertha. I've got several ideas but haven't come up with a design I'm proud of yet.

 

[Ez2cDave]

Does anyone have recommendations on relatively thin wall paper body tube larger in diameter than the Semroc BT-101?

LOC tubing . . . A single layer of lightweight fiberglass ( 1/2oz - 2oz cloth ) . . . After it's cured, peel layers of paper from the inside of the tube, to make it lighter.

The big problem is Nose Cones . . . All nose cones for large diameter tubes are HPR and very heavy. The best option is to make your own . . . The "SORAC Method" works well ( also covered with a single layer of lightweight fiberglass ). See PDF document below.

https://www.rocketryforum.com/threads/12-foam-nc.162415/

Dave F.

 

[James Duffy]

Can you recommend a source for 1/64" plywood that is greater than 12 inches wide? 12 inches rolled makes a tube smaller than 4 inches in diameter.

I'd really prefer a ready made tube rather than a roll your own.

Someone must make thin wall paper tubes greater than 4 inches in diameter?

You are in the realm of the scratchbuilder. Abandon all expectations of ready-made components. Having said that, rolling your own custom tubes from this ply material is really not that difficult.

I generally buy 1/64" ply from National Balsa: https://www.nationalbalsa.com/birch_plywood_s/58.htm

Sig Manufacturing also carries the stuff: https://sigmfg.com/collections/plywood-wingskins

If you need fat tubes roll it in the long dimension, and stack the sections on top of each other. That's how I built my 1/12 scale Little Joe. The completed model stands 4' tall and weighs less than 1500g ready to fly. The airframe is 6.67" in diameter.

Here's a build thread: https://www.rocketryforum.com/threa...-was-anyone-care-to-id-this-component.130403/

Recent flight video:

James

 

[James Duffy]

Another slightly heavier approach would be to use thin sheets of .015" thick G10 sheet, and roll it in the same manner as the thin ply. This is how I produce the 4" tube section on my Bumper WAC models:

https://www.rocketryforum.com/threads/revisiting-the-estes-maxi-brute-v-2.140236/page-5#post-1852935
The thin G10 material is available from ACP Composites: https://store.acpcomposites.com/fiberglass-sheets-natural?quantity=1&thickness=8

If you choose to go with either the thin ply or G10 sheet approaches, be aware that neither can be relied upon to contain an ejection charge. You'll need to plan for a full-length stuffer tube.

 

[James Duffy]

The 1/64 I found was about 1.2 oz/sq foot, James is that about what you have found?

That sounds about right, Frank.

Your Depron (or Depron equivalent) tubes might work for this application, no?

 

[burkefj]

Yes, although you need to work out some sort of cone and stuffer tube arrangement like I do.

Frank

That sounds about right, Frank.

Your Depron (or Depron equivalent) tubes might work for this application, no?

 

[prfesser]

Tubes can be spiral-wound with gummed paper tape--I wrote a leaflet on how it's done, about 30 years ago. You'd be stuck with the diameter of whatever is available for a mandrel---PVC pipe or whatever. And thin-wall large diameter paper tubes are going to flex an awful lot. Probably a reason why they're hard to find commercially.

 

[user 35280]

Can you recommend a source for 1/64" plywood that is greater than 12 inches wide? 12 inches rolled makes a tube smaller th

https://sigmfg.com/collections/plyw...wood-wingskins-1-64x12x12?variant=45032963593
use the drop down menu for the different sizes.

 

[mikec]

The Apogee Saturn V kit uses nice thin-wall cardboard tubes about 5.5" in diameter, but I presume they were special orders and they aren't sold separately AFAIK.

p.s. that was quite a chuff on your LJ flight, James!

 

[James Duffy]

p.s. that was quite a chuff on your LJ flight, James!

Not a chuff, actually! The jump that looks like an ignition chuff is actually the cluster of four plugged A10 motors igniting and burning out before the G40-4 comes up to pressure. On previous flights that was managed by using two separate launch controllers, and igniting the composite motor (or motors, in the case of the FAI version of this model), then waiting a couple of heartbeats before igniting the A10s. We didn't bother to dig out the second launch controller for this flight.