Friday, April 23, 2010
Note the clip attachment.
1st stage ascent.
Staging smoke and weathercocking
DSP stands for Deep Space Probe, 'cause it sure doesn't look like an atmosperic rocket. I named it Goddard in honor of Robert Goddard's famous first liquid fueled rocket which
was likewise a tractor rocket. A tractor rocket pulls from the front rather than pushes from the aft.
The Goddard was inspired and built in a junk pile back in the early '90's. The top cap is from a Colgate upright toothpaste pump that was a good fit on a BT-60 coupler once the internal
threads were moto-tooled off. It was supposed to look like a docking ring, but I never bothered with the extra details. The large ball was from a Valentines balloon bouquet and was clear plastic with a tiny teddy bear inside. Last I looked, it and other sizes were available at Hobby Lobby. The gold pressure spheres are plastic Xmas ornaments. The conical body is the
heart of it and was originally a Yoplait Yogurt cup. The legs are the only costly components, Dave Brown fiberglas pushrods from the hobbyshop. The tailring is a handy droppoff of LOC 5.38 airframe tubing.
One leg is used as a blind launch lug for a 3/16" rod. The other 2 legs each have an ignitor extension wire up them, with flat blade crimps at the bottom for the micro-clips and binding posts at the top for wrapping ignitor wires to.
With a single motor, the Goddard balances behind the nozzle. With two D12's the CHAD booster motor crosses the balance point, and once I even flew it 3 staged. I don't recommend it except in absolute calm. It flies quite well on E11J & F12J's on calm days, and E15W & E18W on breezier days. The old Estes E15 was good, but I have yet to try the newer Estes E9.
Even staged, short delays are the rule.
I have 80% of the parts I need for an H-I sized version, that'll stand nearly 6ft tall.
All Range Safety Officers fear me!
1st pic by KeithAlanK, pics 2-4 by John Lee.