Bodytube , need a nosecone!

[Karl]

I have just scored a nice postal tube with specs of :

ID = 1.997"
OD= 2.102"

And about 20" long . Does anyone know if this would be ideal for a min dia 38mm rocket? And if I can find a lightweight nosecone?
Thanks
karl

 

[Ryan S.]

sandman can make youone, though if you plan to break the sound barrier you should ask for hardwood and coat it with epoxy or even fiberglass, as the high speeds can pull apart wood.

 

[Karl]

WOOD? arrrrrrgh!
This is what I've come up with so far :

3x THOR style fins (3mm Balsa)
24mm/38mm engine mount
3mm , 3x Ply centering rings
Balsa Nosecone


I've simmed her , on a Aerotech I201 , 3500+ FPS , 2500ft+ Alt..

Karl

 

[sandman]

Are you sure???

3500+ FPS is mach 3.218

I wouldn't use a balsa nose cone for that!

You will have a little lump of charcoal at the tip in no time.

 

[Karl]

Ooops I should of said I simmed her with a 15" long bodytube And without TTW fins !!

 

[Missileman]

HMMM balsa NC, balsa fins, mach 3+
I doubt it will get that fast. It should shread long before that.

 

[wwattles]

It could make Mach 3, but only in the cargo hold of something else like a suborbital space plane!

WW

 

[edwardw]

Some company out there makes nosecones for mailing tubes. I really forget who right now. I'll post it if I can find them.

Edward

 

[DynaSoar]

Originally posted by Karl
3x THOR style fins (3mm Balsa)
24mm/38mm engine mount
3mm , 3x Ply centering rings
Balsa Nosecone


I've simmed her , on a Aerotech I201 , 3500+ FPS , 2500ft+ Alt..

The reason you were able to sim it and get those numbers is because the sim package doesn't incorporate *all* the laws of physics.

At the acceleration and speed of an I201, the balsa fins will be left behind very quickly, followed in short order by the body tube doing a banana peel imitation as the nose gets shoved down the tube. It will never reach that speed. If it did.....

3500 fps is not far off the max speed of the SR71. It was made out of special alloys so that it didn't melt due to aerodynamic heating. Its average "heat limit" was 427 degrees C (800 F). At this speed (with the velocity assisted partial pressure of atmospheric oxygen being force fed into it), balsa and paper would give new meaning to the phrase "light this candle". Fwoom.