Hybrid Rocketry - Jim Yehle

UROC Ground Support Equipment

Speed shops seem to only be able to fill tanks which have 4AN fittings. This photo shows a CGA-326 to 4AN adapter installed on the tank. (It weighs 180 grams.) The tag shows an empty weight of 27.6 lb. But its actual useable (liquid) nitrous empty state is more like 29 lb. probably because the pickup tube doesn't go all the way to the bottom of the tank. It began life as a 20 lb. CO2 tank. I don't know the density of CO2 (NO2 has a specific gravity of .8 at 20°C) but the useable nitrous capacity is about 15 lb, which works out to roughly 8 liters. Checker auto parts on 45th south State will fill for $3.75/lb. as of Sep 2006. Ask for Ryan or Justin, since not everybody knows how to operate their nitrous equipment. Call first: 801-281-5515.
The solenoid valves for nitrous fill and dump are now on the nitrous tank. It doesn't take a lot of force on the wrench to tighten flare fittings such as the CGA-326 tank fitting or the 4AN fill-hose fittings. The brown wires and plug go to the Fill solenoid, the white to the Dump solenoid. The pressure should be between 550 and 900 psi for safe end effective hybrid flying. The right photo shows where the nitrous (blue) fill tube gets connected.

This is the green oxygen tank strapped onto UROC's hand truck. The red 4AN fitting can just be seen behind the black solenoid valve. It's a good idea to keep the tanks strapped to the carrier since the fittings can get damaged easily if a tank falls over. Hypertek and West Coast Hybrids use oxygen, but Sky Ripper and R.A.T.T. don't. Oxygen fill lines are red. The electrical wires, plug, and outlet for oxygen are black. The regulator should be set to about 100 psi. The high-pressure gauge (upstream of the regulator) tells you how much oxygen remains, unlike with nitrous.

UROC Nitrous Charges

Please log all fills. The charges are due to UROC according to the following table:

Skyripper 29mm 29/75 29/125 29/185
  $1.50 $2 $2.50
Skyripper 38mm 38/220 38/400 38/580
  $3.50 $4.50 $5.50
Hypertek 54mm I/J/K 300cc 440cc 835cc
  $4 $5 $7.50
Hypertek 75mm L 1685cc 2800cc
  $13 $20
Hypertek 98mm M 3500cc 4630cc 5478cc
  $25 $32 $38

Hybrids - Introductory and How-to Links

Vendor's and Manufacturer's Links