CRAZY G's - MD G80-10 Rocket

[Willie]

My 10yo son asked to build a rocket that would break the speed of sound. Due to the ease of build, I convinced him to build a minimum diameter tube fin rocket (LINK BELOW). We have flow this successfully multiple times, but the speed is estimated to be only 85% the speed of sound, and our estimated max altitude is 3558' on a G80-10. This original rocket is a blast to watch...

But, He is asking if we can achieve greater speed and height. So, we are on to another attempt.

This second design goes back to fins to minimize drag. I plan to tip to tip FG these for strength (I will need to learn this build technic). Using OpenRocket, I have a design that achieves 4% over the speed of sound, and 3693' on a G80-10. It has a balsa nose cone in the design, and a body tube at ~30".

MY QUESTION: what body tube material would best be suited for maximum altitude on a G80-10? With the additional speed, I'm concerned about sticking with the original body tube used for the tube fin design.

The tube rocket was built with SEMROC thick wall cardboard tubing typically used for motor mounts.

https://www.rocketryforum.com/showthread.php?67214-Minimum-Diameter-tube-fin-rocket

 

[cbrarick]

First: It's extremely difficult to break the speed of sound with tube fins. Way too much drag. Switch to normal fins, small span, generally long root. It's not so hard to break mach then.
Second: tip to tip is usually a big waste of time. Fins with a long root might need them to decrease flutter. Other fins that get laminated are special ones (think estes mosquito) or very large ones (I'm gonna do my mega wildman but it's gonna fly on a P.
Material? Normal LOC tube works fine. I have a vulconate that's broken mach on the J600 (mach 1.5) without any fancy reinforcement.

 

[Willie]

My son and I will make duplicate rockets to drag race them at a launch. Not really expecting to get either of them back, way too high, way too fast.

Decided to make some progress on this build by cutting the fins...


Marked up some fins on Midwest Product 1/8 (3mm) birch plywood


Here is the layout. Very simple rocket. The tube is SEMROC LT-115300 29mm motor mount tubing. Recovery will be a streamer.

Now, what is the best way for motor retention for an ESTES G80-10?

 

[Willie]

Here is a snap shot of the OR file for this one.

it looks like it will be around 7 oz.. Hit about 4000 ft apogee... and reach 1.2 mach.

 

[tmacklin]

My son and I will make duplicate rockets to drag race them at a launch. Not really expecting to get either of them back, way too high, way too fast.

Decided to make some progress on this build by cutting the fins...

View attachment 250769
Marked up some fins on Midwest Product 1/8 (3mm) birch plywood

View attachment 250770
Here is the layout. Very simple rocket. The tube is SEMROC LT-115300 29mm motor mount tubing. Recovery will be a streamer.

Now, what is the best way for motor retention for an ESTES G80-10?

Epoxy?

 

[Cl(VII)]

When I built something similar, called mine "Single Use" i held the motor in with heavy aluminum tape. I know it didn't spit the motor because I actually got it back when someone popped their main at apogee, and saw the mylar streamer from where their rocket landed.

 

[dave carver]

Run more sims with different weights. If speed is the goal then light as possible is the aim. If altitude is what you're after then optimum weight is what your looking for and that's what the sims are for. I run mine in 1/2oz increments then to grams for fine tuning. Most minimum diameter rockets will need a little extra weight...unless over built of course.

 

[Willie]

Run more sims with different weights. If speed is the goal then light as possible is the aim. If altitude is what you're after then optimum weight is what your looking for and that's what the sims are for. I run mine in 1/2oz increments then to grams for fine tuning. Most minimum diameter rockets will need a little extra weight...unless over built of course.

I noticed that affect when playing with the OpenRocket's optimization component. Since by boy and I are building these MD rockets, I'm going to let him optimize his for either height or speed. For me, I'm going to height, which requires some additinal weight. I'll wait until the rocket is complete to get an accurate build weight before adding what is needed....

I believe the boy wants straight up speed, but he may change is mind before we get them completed.