HyperTEK Experimental Motor Test Flight April 10, 2005


Re: my HyperTEK Experimental Hybrid Page. I flew my first HyperTEK Experimental motor flight at the Whitakers WELD launch.

Grain Data

15% ZnO (chunky) 85% PBAN binder cast in 1.5" SCH 40 PVC with 1" core (coring rod 3/4" SCH40 PVC) long enough for AT 1280 case and my adapters.

I had to mill the end of the grain at the field with my Dremel so it'd fit the adapter bell throat that I had. This area will get more work - but I wanted to fly so I milled this by hand at the field. As a result the PVC was a bit thin and burned through in places.

Due to field modifications, I do not have flight weights for this grain. I could probably extrapolate it.

Motor / Injector / Tank

440cc tank with 0.125 injector (240NS thrust) on HT-AT Mryazek adapter, 1280ns AT case, with custom nozzle.

Rocket

Ignorant Of My Destiny The flight was nominal, with good thrust, lift, burn, noise, and to about 1154 feet. The rocket is 4" diameter, about 7 1/2 feet tall, and about 12 pounds. I haven't yet flown Ignorant on the 440 tank with a sport load so can't comment on comparability, although on the 835cc tank on sport loads altitudes are about 3400 ft.

Pictures / Grain Analysis



Here is the grain as removed. The entire end isn't burned off, just the upper 1/8" for about 180degrees of arc. The rest is scortched. Click on it for a very high resolution photograph.



I've sectioned it, and placed the nozzle and adapter in their respective places in pretty close alignment to how it was flown. The clearances shown are for o-rings that are not shown. Click on it for a very high resolution photograph.

Note the nozzle end regression. It wasn't lined all the way to the nozzle entrance so we started burning pipe itself.  On the forward closure / adapter, I think, at minimum, the shoulder will need to be milled to accomodate full pipe thickness, if not a little more.


Here you can see a cross section. The nozzle end regression was greater - but note that due to a casting issue that area wasn't lined. Click on it for a high resolution photograph.

Results / Analysis

It seems to show that straight pipe might fly on the .125 injector with the 440cc tank, and that with a full length lining, that the ZnO/PBAN lined grain might fly on the 835cc tank. The nozzle end lining issue also suggests that a post combustion chamber (perhaps on a 1706 case) would need to be lined for a 835cc tank burn. The 835cc tank, with or without post combustion chamber may provide higher ISP by this combustion evidence.

Due to field modifications, I do not have flight weights for this grain. I could probably extrapolate it as well as regression.