Concrete Form Airframe Project

Always wanted to try and build a project using concrete form tubes.
Here is my design for a 16" airframe.

Good cheap tube , I'm doing a 8" BLU-97B. 10 Bucks for my tube

The concrete form tubes are usually stored outdoors and most were fairly out of round and/or severly creased.Since the tubes are “nested" for ease of storage and shipping it is important to select tubes of the same diameter. I decided on middle sections of some of the less out of round tubes and stored them with several bulkplates installed. To help work back into shape. Each 16x48” tube weighed 10 lbs.
Pictured below are the unfinished tube, custom Python Rocketry NC and first airframe layup. I used 1 wrap od 8oz FG and 1 wrap 8oz CF. I might lose a couple inches of length to a little edge hinkiness

I get all the same size tube . As needed

chris m said:

Good cheap tube , I'm doing a 8" BLU-97B. 10 Bucks for my tube

Click to expand...

Cool, what does a BLU 97B look like?

Here it is it's short for its diameter at 54" tall

The nose cone is a small section of tube with foam on top that is shaped and glassed then a nipple is put in the center

mIcahel said:

Always wanted to try and build a project using concrete form tubes.
Here is my design for a 16" airframe.

View attachment 159978

Click to expand...

Your design looks awesome!
I've ventured into the concrete section at Home Depot looking at those tubes.
Strange how many are different than advertised sizes, however I measured all of them
and found a few that matched.
How much did you pay for the Nose Cone?

JP

JP Morgan said:

Your design looks awesome!
I've ventured into the concrete section at Home Depot looking at those tubes.
Strange how many are different than advertised sizes, however I measured all of them
and found a few that matched.
How much did you pay for the Nose Cone?

JP

Click to expand...

Thanks, I always browse the tube section at Home Depot when out shopping for misc. supplies. Check out the "Python Rocketry Custom NCs" thread
under Product Reviews for info and discussion on pricing. Good luck with your project!

For the vendor section , A nose cone that could be the around the same size was done for $325 plus shipping
Nose cones can be made , there very time consuming.

Not really breaking any new ground with the avbay. Trying to keep it as light as possible because it will be offset to the edge of the airframe so
as not to require huge static port holes.

Completed the airframe layup and will move on to the coupler next. I was planning on using the lighter of the two sections for
the aft airframe, but they turned out almost exactly the same weight so I will choose based on hiding imperfections with fin slots
and graphics. The CF turned out to be less expensive than a decent quality primer/paint for this project.

Real Sonotubes are generally all the same size and near perfectly round if you get the Sonotubes designed for making columns instead of forms. The concrete tubes sold at your local home improvement store are designed for making footings so size and roundness isn't nearly as critical.

belfert said:

Real Sonotubes are generally all the same size and near perfectly round if you get the Sonotubes designed for making columns instead of forms. The concrete tubes sold at your local home improvement store are designed for making footings so size and roundness isn't nearly as critical.

Click to expand...

I looked at some Sonotubes at a builders supply and found them unsuitable because of a glossy rain resistant finish on the outside and inside that made them no good for reinforcement.
They also had a "strip cord" feature that was designed to make removal easy, but did not seem like a good feature for a rocket airframe.

I am getting some from menards that's white and made for another company . There sono tube but white and each size has three size one is the 8" and one fits inside and the other outside

Very interesting CF. That weave looks massive! Where did you buy it?

Alex

Soller composites 8oz 2x2. Definitely not recommended for smaller airframes


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Really look forward to following this one, keep posting!
Scott

Got tired of laminating so I cut out the "wings" and fins. The wings are CF .5" honeycomb panel, could not believe how strong and light this stuff is.
The 24x24 panel would not flex at all by hand and it weighs nothing. I know the grain is wrong on the fins. They are getting some reinforcement.
Hoping to keep the whole bird less motors at <80lbs.

chris m said:

The nose cone is a small section of tube with foam on top that is shaped and glassed then a nipple is put in the center

Click to expand...

The nose cone is made with 40 psi foam over phenolic airframe tubing. The tip on this cone is hardwood over a 3/4 x 16 inch aluminum rod. The aluminum, hardwood and foam are turned as one piece, then filled, sanded, glassed with 2 layers 6 oz plain weave and sanded again.
Please check my website for more info. www.pythonrocketry.com

What are you using to power this beast? Where you live? country?

The plan is to fly at URRF in NY this June. won't have motor config until
I have a better idea of final weight. Likely a central N air starting 2 Ks or
Baby Ls.


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can't wait to see it


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OHHH! Good a NY flight, maybe I will be able to get there and see it up close. I did a thrust plate for a similar SonoTube project with 10 motors in it. Not sure if he has flown yet, he was intending to fly at one of the Red Glare events........

Love the creativity of a scratch build like this. Keep the momentum !!

mIcahel said:

The plan is to fly at URRF in NY this June. won't have motor config until
I have a better idea of final weight. Likely a central N air starting 2 Ks or
Baby Ls.


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Click to expand...

SCP said:

OHHH! Good a NY flight, maybe I will be able to get there and see it up close. I did a thrust plate for a similar SonoTube project with 10 motors in it. Not sure if he has flown yet, he was intending to fly at one of the Red Glare events........

Love the creativity of a scratch build like this. Keep the momentum !!

Click to expand...

Thanks, send me a PM if you have any unistrut airfoil rail guides available.


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Misread title- thought you were making a concrete rocket.:y:
What does Rocksim day about the altitude with K and airstart Ls?

PM sent! (sorry for the delay )

Definitely guilty of procrastination on the coupler and NC shoulder. I was getting a little burned out of tube
laminating. In the end it was necessary to cut out a 1.75" strip of tube in order to get the correct fit.
Also applied a layer of 4oz FG to the airframes in order to reduce the basket weave effect of the CF and
allow for better adhesion of the vinyl.

Made a decision to use 2 part foam in the NC shoulder to reduce the chance that the massive separation
charge will deform the shoulder and cause it to jam.

The nosecone is going to come down separately from the rest of the rocket by the 69 recovery technique:

7' Rocketman chute for the NC will be pulled out of deployment bag attached to the upper airframe bulkplate.

20' Rocketwoman chute for the airframe will be pulled out of the deployment bag attached to the NC.

This should allow me to get both chutes out even if there is a less than forceful separation.

View attachment 170702

That's a really cool deployment technique.