Transonic plastic nose cone

[jason0]

Hello,

I recently certified L1, and am now having a lot of fun designing, in openrocket, options for the next rocket that I will build. I am looking at altitude-optimized, almost minimum diameter designs, so most are simulating at mach 1-1.3 max (with accelerations in the 15-20g range), using longer burning motor options. My question is, will standard small plastic nosecones, such as the LOC PNC-1.52 or apogee PNC 29, hold up to this velocity range?

Extensive googling and searching on this forum has revealed plenty of useful information about optimal shape and dimension, but most threads here seem to be about pushing mach 2 or 3. I'm hoping that a few of y'all will be able to share your experiences flying plastic nose cones in the transonic range. If anyone can point me to resources with these answers instead, that would also be greatly appreciated.

Thanks
-Jason

 

[tfish]

Jason, I've been pushing both the LOC 1.52 and 2.14 nose cones to just below mach 2 for a few years now. Around mach 1.8 Rustoleum paint becomes affected...bubbles and starts to soften. Both the above nose cones are fairly thick which aids in their ability to withstand the heat. "Real" mach heating starts around mach 2.8..in my opinion.

I've not used any of the Apogee nose cones.

From 2003...LOC 2.14 plastic nose cone.....flew on a K1275, went to 19,936'... simmed at mach 1.98 and 46g's

Tony

 

[ksaves2]

Time at Mach also plays a part. I remember seeing a picture of one of Robert DeHate's rockets that was I recall above Mach 2 for something like 26 seconds. Boy it was really cooked and the lamination on the tip to tip fins was really ablated
away from the aerodynamic friction. That's one advantage of staging. Get it "up there" in the thinner air then punch it!

I don't think you'll have any problem with Mach 1 to 1.3 with the LOC nosecones. Kurt

 

[retortec]

I agree with ksaves2 the time spent in transitions a big factor. I have been using the Apogee PNC29 nose cone on several mid power supersonic flights with no problems. My last flight exceeded Mach 1.7 but the burn was just over 2 seconds at 56g. Trying to create durable surface finishes is always a challenge. Best bet is to make it as smooth as possible. My next build will be pushing Mach 1.8 at 7000 feet.