Project
1230 Static

Post-flight Analysis

• Three static engines were tested at 300, 350 and 400 Kn to try to arrive at and not exceed a chamber pressure of 300 PSI due to the fact that the 2" PVC is rated at 280 PSI. To my surprise, the first and smallest of the three static engines, had a maximum thrust of 199 lbs. which according to Po = F / (Cf * A) means the chamber pressure was 298 PSI assuming a 1.4 nozzle coefficient. This was exactly what i was trying to achieve and what made it even better were the final numbers; a 39% K, K400 rating with a fuel efficiency of 451 Newtons per pound of fuel! Unfortunately, it also meant that the other two larger engines were going to exceed the pressure rating of the PVC.
• The second static exploded after maxing out the gauge.
• The third static, to my surprise, did not explode.
• Another interesting fact is that this fuel exceeds the efficiency of the best KnSu engines I ever tested. See this graph for data. Now, of course this could be because of a different nozzle design I'm using now but even so, Kno3 / Corn Syrup is right up there with Sugar. KnCs also has the added advantages over KnSu of being remaining very flexible after the propellant is cured, slightly slower burning and much more pourable during the casting process.

• The first static engine was 60/40 Kno3 / Corn Syrup.
  • 23.00" Casing
  • Core burner, case bonded.
  • Fuel weight 3.95 lbs.
  • Casing weight 1.95 lbs.
  • Total engine weight 6.14 lbs.
  • Throat .78" diameter.
  • Expansion ratio 3.7:1
  • Divergent nozzle 15 degrees from center line.
  • KN 300
  • 1781 Ns.
  • Average thrust 400 Newtons.
  • 39% Full K
  • K400
  • 451 Newtons per pound of fuel.
  • Maximum chamber pressure 298 PSI
  • Maximum thrust 198 lbs.

• The third static engine was 60/40 Kno3 / Corn Syrup.
  • 30.00" Casing
  • Core burner, case bonded.
  • Fuel weight 5.18 lbs.
  • Casing weight 2.32 lbs.
  • Total engine weight 7.73 lbs.
  • Throat .78" diameter.
  • Expansion ratio 3.7:1
  • Divergent nozzle 15 degrees from center line.
  • KN 400
  • 2377 Ns. (Pressure above 200 lbs. was assumed)
  • Average thrust 530 Newtons. (Pressure above 200 lbs. was assumed)
  • 86% Full K (Pressure above 200 lbs. was assumed)
  • K530 (Pressure above 200 lbs. was assumed)
  • 459 Newtons per pound of fuel. (Pressure above 200 lbs. was assumed)
  • Maximum chamber pressure was 500+ (Pressure above 200 lbs. was assumed)
  • Maximum thrust was 370 lbs. (Pressure above 200 lbs. was assumed)

Construction

• 2" PVC pipe and fittings with a .78" diameter heavy steel washer in the throat.

Pros

• Propellant remains flexible after it is cured.
• Propellant is very pourable.
• Propellant is slightly slower burning compared to KnSu.
• Inexpensive.
• Easy to work with.
• Flexible to prevent cracking with case bonded engines.

Cons

• Slightly more expensive than sugar but the added advantages outweigh the small cost disadvantage.

Pictures

Video

• Static 01 Gauge
• Static 02 Gauge
• Static 03 Gauge
• Static 01 GIF
• Static 02 GIF
• Static 03 GIF

Drawings

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