Estes S and T motors
 

Sorry if this is supposed to be common knowledge, but when did Estes stop making the "s" (short) motors and start the "T" motors?

I see that there is a mini brute sprint (up for auction on e-bay claiming to be 37 years old. It is the "t" motor version (1215 K-15). I flew the "s" motor version (K-15) 38-40 years ago.

The changeover first showed up in the 1972 catalog.
http://www.ninfinger.org/rockets/no...a/72est038.html
Estes did sell 5/20 adapters for some of the older models that used 18mm S engines.

I went and looked through that catalog.
I'd forgotten about the "Series" engine designations.
Series I were standard 18mm x 2 3/4" engines
Sereis II were the B14
Series III were the shorter 18mm x 1 3/4" long S engines
Series IV were the D engines.


The "S" stood for short engines
I guess the "T" designation (13mm) is for tiny.

Hope this helps!

I suspect "T" = Thirteen mm...

The Mini-Brutes were first on sale at NARAM-13 in August 1971, but they had been shown over the spring at the various model rocket conventions as MPC introduced their Minirocs and Minijets.

The "Shorty" motors were phased out over the next year.

Also, I think you mean Sprite (the tumble recovery, ring-tailed rocket) not Sprint (the low drag form factor rocket which used standard motors.

Tiny would be much more obvious than thirteen. Especially since their competition, the MPC Minijets were labeled "m" for Mini, and their own "s" engines were for "short."

You are correct......it should have read Sprite.

Thanks to all! I do remember the mini- kits coming out now that you mention it.

I really loved my short engine two stage midget.

http://www.ninfinger.org/rockets/no...a/70est036.html

edit: And birdie too!

http://www.ninfinger.org/rockets/no...a/70est056.html

I much preferred the 'shorty' version of the Midget over the mini-brute version, but the mini-brute version of the Beta was beta-r than the shorty version.

Thanks, Sven Knudson, for posting the old Estes catalogs. What a trip to an earlier life. :)

With a band saw, you could make more 1/2A6-2S Series III motors at least for an "S"-version Sprite, and if Quest brings out an A6-0 booster motor as Bill Stine hinted at last year, it might also be a candidate for "S-ifying."