The longer I waited to stage, the more likely the sustainer would survive the motor burn. I made sure I had the correct weights. Also having good thrust curves to base the simulations off of made it much easier. I was shooting for Mach 0.85, in reality I could’ve coasted a bit longer.
I still wonder if waiting a little longer to stage would have actually lost you altitude. As it was, the sustainer coasted down to Mach 1.06 and then lit. If it had coasted down to Mach 0.85 it would have passed through M1 twice. Once when slowing down and once after it lit. That seems like a high drag scenario to be avoided. Although, I guess the trade off is the drag from that scenario versus the drag at max speed and at what altitude max speed occurs. A sim is probably needed to say which is best. Better yet, run the experiment! Fly it again but with a longer delay this time.
Vern you do indeed lose altitude albeit only about 5k but top speed is 0.2 Mach lower and at a higher altitude +5k which I’m guessing the leading edges would appreciateI still wonder if waiting a little longer to stage would have actually lost you altitude. As it was, the sustainer coasted down to Mach 1.06 and then lit. If it had coasted down to Mach 0.85 it would have passed through M1 twice. Once when slowing down and once after it lit. That seems like a high drag scenario to be avoided. Although, I guess the trade off is the drag from that scenario versus the drag at max speed and at what altitude max speed occurs. A sim is probably needed to say which is best. Better yet, run the experiment! Fly it again but with a longer delay this time.
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233 s is quite high for amateur propellant but not extreme. Shuttle propellant at 1000 psi and sea level had Isp of 266, if memory serves.
It was similar to what you see on the booster which is good to know. I had never tested that igniter at altitude. There was also a sealed “burst” cap on the nozzle which was only tested on the ground prior to this flight. The M830 ground test on YouTube used a different igniter and just a friction fitted cap which I moved away from because of slow ignition.
Yes, I think it is. If I had not landed on rocks, the second stage would have been good for reuse but one of the fins got clipped and the upper airframe chipped. It was a nasty spot to land in. The first stage is ready for another flight.
Quite awesome and congratulations to you for the record. I agree there is a gray area in the definition of amateur and your achievement is ground breaking when factoring in resources. Your rocket might have professional value as a sounding rocket. I am not sure the cutoff, but you are close. You might want to consider that. I am doubling down on publishing
Space historians I am sure would be interested in noting this accomplishment.
. Great guy and I'll always enjoy sitting around the campfire talking rocketry with him.
I don't have too many pictures of the sustainer, as I was helping Kip retrieve it and didn't bring my camera. But I have some of the Booster!
Great photos and like how the open end of the booster dug into the playa.
That's the interstage that sat on top of the booster!
Now I see it. Thanks.
Are those just surface mounted or did you cut slots into the airframe?
Surface mounted. They’re aligned straight to the airframe with aluminum angles. No pics of that because my hands are full when tacking one in place.
I suspect lots of us have questions on your project. Fin alignment would be one of mine. Almost all of the jigs I have tried tend to be worse than my eye. (I can always see a slight misalignment.) I realize taking a picture is hard but maybe take a mock pic with a generic tube and fin?
)... are the tolerances on drawn tube good enough, or do you have to machine the tube, well, machining the inside of a tube concentric to the outside is no walk in the park. And again, what is "concentric enough?
