Sunday, February 22, 2009

Where does time go?

I can't believe that Feburary is almost over.  Due to my day job, I haven't had much free time to work on the new N2O-propane motor.  However, today I finally finished mounting it on the test stand.  I intend to test ignition and thrust levels using very short duration tests.  After I've gotten that worked out, I will go through the trouble of adding the regenerative cooling to the chamber.

Tuesday, February 17, 2009

The Rest of the Story

Here are the results for the other two cases...

M 1.851
p 29530 Pa
rho   0.398 kg/m^3
T 258.4 K
V 596.4 m/s
Drag 1750 N
Cd 0.764

M 0.936
p 27640 Pa
rho 0.377 kg/m^3
T 255.6 K
V 300.0 m/s
Drag  327 N
Cd 0.596

Monday, February 16, 2009

Unreasonable Request

I offered to run some CFD for Paul Breed of a simple "rocket like" geometry - a 8" by 8' tube.  I picked an arbitrary ogive nose cone and a bluff tail.

Here is the Mach number contour for the 150 m/s case.

The free stream conditions were:

M 0.468
p 27580. Pa
rho 0.376 kg/m^3
T 255.4 K
V 150.0 m/s
Drag 55.1 N

The calculated Cd is 0.40.   300 m/s and 600 m/s results to follow.