To all the BALLSers our there

Good luck! Wish I was there.

Maybe they will kindly post pictures.

That's the R booster two stage, right? Booster CATOed not long after that?

Regardless, that's incredibly impressive.

Yes - a 3% R16k.
Our spin-caster failed to coat the motor right behind the nozzle.
There was no time to strip it out and re-do the coating, so we tried to fix it.
Failed right there.....melted off the end of the motor.

FredA said:

Yes - a 3% R16k.
Our spin-caster failed to coat the motor right behind the nozzle.
There was no time to strip it out and re-do the coating, so we tried to fix it.
Failed right there.....melted off the end of the motor.

Click to expand...

Just pressing the button on a project like that is one heck of an accomplishment Fred. And maybe CATO whilst a correct description doesn't really encapsulate the relative clean failure of a spat nozzle which is what I was told occurred? My expectation is that most of the stack should ideally survive that failure mode. Still, I'm working on word of mouth so I could easily be wrong!

Pure thermal issue.
No sign of any pressure problems.
The closure pins were all intact and their holes were not stretched.
The propellant/geometry all seemed nominal.

We've had success in our thermal protection in past experiments & flights.
But we were screwed when the coating failed to cover.
All indications point to a successful boost had we not had this insulation problem.

Ya gotta love a 25-foot flame coming from a 6-foot combustion chamber!

FredA said:

Ya gotta love a 25-foot flame coming from a 6-foot combustion chamber!

Click to expand...

Indeed! I like using the flame length compared to total rocket length as a bit of a low tech metric to highlight just how aggressive a flight profile will be from a speed perspective. Anytime you have a flame that approaches or exceeds the total vehicle length you're doing something right imo! My single stage MD rockets routinely exceed this metric. That said yours is a two stage stack and still fits the metric nicely. That's INSANE!

Ya gotta love a 25-foot flame coming from a 6-foot combustion chamber!


Can you share any info about the motor? I'm guessing that it is at least a 10 inch diameter motor to be a R class and only have 6 feet of fuel .

Eric

The motor was a 8" case-bonded, 72" long mono-grain Finocyl using my pin-in-slot closure design using 3/8" pins in a 1/8" wall motor tube.
Burnsim called it an 3% R-16150 with a 10.3 sec burn time.
Volume loading was 85% with 175 pounds of propellant
Nozzle throat was 3.0"
Take-off thrust was ~2900 pounds which puts the stack pretty close to 10:1 TTW.

Fantastic work no the burn time Fred. That's really impressive.

I took a little drone video at the launch and caught a few of the flights. I think I got Neil Anderson's two-stage fight, Fred's R motor cato and Buddy Michaelson's L3.



Jim