Larry's SR-71 Blackbird

 


I modified the Estes kit (no longer made, but still for sale occassionally in some Wal-Marts or hobby shops) to allow the option to use either one engine (as designed) or three engines (see below left & right)! I used epoxy instead of wood glue to attach the wings and side "jet engine" tubes, then modified each of the side tubes to accommodate an engine. I had to shave the inside of the lower exhaust cone to allow an 18 mm engine (A~C sized) to slip in and added an engine mount to each tube. The central engine will still provide ejection for the parachute, and the side pod engines (if used) should just eject out when exhausted.

WRasp simulation  predicts it will go ~62 feet on one A-8, ~350 feet on three A-8's, 220 feet on one B-6, 990 feet on three B-6's, 650 feet on one C-6, or (yipes!) 2100 feet on three C-6's. Of course, I'd never see it again! One reported problem with the SR-71 model is it's tenency to "weathercock", or tilt into the wind during flight. This means it could take off horizontally under power and quickly disappear from view! This is a calm day only rocket!


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