Velocities

[Matt]

How fast hav you ever flown a 3" performance rocketry fibreglass nosecone?

How fast hav you ever flown a 3" PML Plastic nosecone?

 

[Missileman]

It's not saying much but I flew a PML 3"
plastic cone to about 600 f/s. (Rocsim calculated speed, no electronics ondoard)
PML nosecones are pretty tough. I wouldn't expect any problems with mach speed.

 

[Rocketjunkie]

I've flown a LOC plastic nose cone to mach 2.7. A custom fiberglass nosecone has reached mach 2.3. No damage beyond paint removal in either case.

 

[Matt]

Do you guys hav any idea how long it takes for the rocket to come from mach 2.5 to transonic speeds.

I imagine it's not very long although my thinking shows a very tight margin in my mach inhibitor on my electronics, anyone have any idea?


Thanks heaps
Matt Graham

 

[GL-P]

Use a program like Rocksim or Wrasp to sim ur flight. You can also get an accelerometer based altimeter which isn't affected by mach.

 

[bobkrech]

Do you guys have any idea how long it takes for the rocket to come from mach 2.5 to transonic speeds?

I imagine it's not very long although my thinking shows a very tight margin in my mach inhibitor on my electronics, anyone have any idea?

The rocket will be probably be supersonic for 3-4 seconds. Run a sim to verify.

You want to set the mach inhibit for 6-8 seconds or so, however it would be better to use electronics that employs an accelerometer for drogue deployment so that you don't have to worry about a mach inhibit at all.

Bob Krech

 

[Matt]

I wanna use a 3/8 launch lug... but i hav to make it only 36mm long (1.4") is it best to hav the lugs longer or shorter.... (shorter less drag on the lug... but longer more material to attch it's self to the airframe)

Whats are you guys sugestions

 

[PatFloyd]

FWIW... Adapt altimeters have a software mach lockout on them and it works really well. You don't need to do anything to them but size the vent holes correctly. It makes going Mach really simple.