Quantcast

Small motor staging

The Rocketry Forum

Help Support The Rocketry Forum:

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
I like multiple stage rockets! Its very cool to see the stages fall off the back just like we saw when the Saturn V sent us to the moon. But I don't like building big rockets! Big rockets equate to big money for motors and materials (not trying to start another thread here please), and lots more storage/building room needed, and transportation issues...

I like SMALL multiple stage rockets, using small motors (I like to get my rockets back), so where do I find or make A8-0's...

I'd like to use even the 'T' motors A10-4t... to make an A10-0t...

Can you make an A8-0 by knocking out the ejection charge and delay stage of an A8-3, then adding black powder (or the ejection charge) back into the motor? How? Gotta site?

As always, Thanks In Advance for the Information.
 

BlueNinja

Well-Known Member
Joined
Jan 18, 2009
Messages
2,690
Reaction score
1
It would work but....


It would be against teh NAR code, as motor modification. I think you cna buy A8-0s at the store, but you cna buy B6 and C6-os.
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
38
Location
Washington DC
3 words Scadaman29325:
DON'T TRY IT!!! altering motors violates ever single safety code there is and voids any insurance you might have. Not to mention wouldn't be very helpful anyway, you wouldn't be able to tell if you removed the ejection and delay or left some or went to deep reducing the motor impluse. Not to mention the potential for igniting the propellant by friction while you digging aroung in there. Please!!Don't try this.... it isn't worth the trouble, danger and potential injury to yourself and other.
 

jflis

Well-Known Member
Joined
Jan 18, 2009
Messages
15,353
Reaction score
34
The B6-0/A8-5 multi-stage combination makes for a nice 2 stage for small fields. (well, relatively speaking... LOL)

The FlisKits Cheetah! goes well on that motor combination, but I still wish for the days when 1/2A6-0 and 1/2A6-4 motor were available, even the 1/4A3-0T... man, great for small field multi stage!

Keep watch for an upcoming *small field* two stage kit... :D
 

shockwaveriderz

Well-Known Member
Joined
May 25, 2002
Messages
2,466
Reaction score
1
scadaman:
thats a BIG NONO...

I believe that Red Arrow Hobbies may have some A10-0T motors that you could use with say 1/2A3-4T,A3-4T or A8-5 upper stage motors.......or perhaps even with micro maxx upper stage motors?

http://www.redarrowhobbies.com

also check out my Motor dealer Listing on Page 2 of the Propulsion section and make some inquiries....I'm sure you may be able to find some A10-0T and perhaps even some A8-0...


good luck
 

sandman

Well-Known Member
Joined
Jan 18, 2009
Messages
10,468
Reaction score
5
The new Estes Renagade is large (BT-60 sized) and has lots of fins.

A B6-0 B64 combo won't go that high.

If you search at some hobby shops you can find some 13 mm A10-0 booster motors.

They are still around...just not made any more.

Dave at Red Arrow Hobbies has some.

sandman
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,356
Reaction score
4
scadaman,

It is theoretically possible to convert a single or upper stage motor into a booster. Aside from the safety and NAR-rule aspects, there are some practical problems.

First off, it isn't that easy to do without damaging the rest of the motor. The clay retainer cap is usually in there pretty solidly and will take some force to crack/displace. That amount of force can also carry on through and crack the main grain, or separate it from the sidewall. Neither of those is a good thing. (Can you say "CATO?")

Let's say you can get the clay cap out---the ejection charge is granular BP, and could be removed with a little work and the right tools, but if you make one mistake you are going to have a fireball in your lap. Not a good thing. (Would you like to have children someday? Are you really good at Braille?)

Let's say you can get past the cap and the ejection material. The delay charge is hard-packed inside the motor casing, and would also require rather strenuous efforts to dislodge. Same danger of damaging the main grain, plus you will not be able to recognize where the delay portion ends and where the main grain begins (they physically look the same). If you leave a blob of delay on top of the main grain you will significantly reduce the chances of successful staging. If you dig out all the delay and take part of the main grain with it, you are reducing your impulse. Neither of those is a good thing.

Finally, even if you mod the motor and everything works fine, it will be a royal PITA to repeat this for the next flights.

Best not to mess with these motors, but to find an available booster and design a rocket around it. If you want small-field performance for safe recovery, pick out a BT-60 or -70 airframe tube and some big fins---it won't go far.

Myself, I am not even gonna make jokes about motor mods anymore, because I got publicly flogged here the last time!
 

scadaman29325

Catching up and tripping all over myself.
Joined
Feb 6, 2004
Messages
389
Reaction score
65
Location
Clinton, SC
Ok, I can take a hint.:(

As far as that goes, I met a young man last month that had been 'playing' with a rocket motor several summers ago. He had done something similar to what I was describing, except he had poured a little black powder out of the motor and was trying to light it. He was still holding the motor casing in his other hand when the small pile ignited. The flash set the rest of the motor off which he was still holding.

Results:
Third degree burns to his whole hand and exposed some areas right down to the bone!

His hand had healed very well but you can still see some burn scars.

Can you say OUCH!
 

Karl

Well-Known Member
TRF Supporter
Joined
Jun 30, 2010
Messages
2,456
Reaction score
25
:( Well i guess thats what you get for messing around with rocket motors , no matter what size!
Even if it was to be tried , you wouldnt be able to remove ALL of the delay element , and that would fail to ingite the 2nd motor.
- Karl
 
Top