Trivia question--

[powderburner]

I am trying to re-work some motor performance models and need a little help remembering the old (circa '60s and '70s) Estes motor details.

I remember seeing a variety of motor case thicknesses on the basic 18mm motors but don't remember which ones or how thick. Does anyone have any notes on this?

Also, approx what year was it that Estes switched from paper retaining caps to ceramic?

Thanks ahead of time for your help.

 

[powderburner]

Lots of lookers, but no posters?
Now I KNOW some of you guys are as old as me (or more so) and probably used the same variety of Estes motors 30-40 years ago. I am hoping that someone has better memory than me . . . or has kept a collection of old motors.
Help, please.

 

[sandman]

powder,

Remember, most of us are BAR's and I believe the change came when most of us were "away" from the hobby and never really saw the change.

Or we never noticed it.

 

[BobH48]

I have some D13-3's with a date code of 1-16-70 that have paper retaining caps.

I have some 1/2A6-4S motors dated 3-30-71 with a clay retainer.
They also have a very thick casing. I'm guessing twice as thick as the current 1/2A6-2's.

The old A5-2's and A5-4's had a thicker casing. I remember those because in light rockets they had a slower liftoff than the A8's.


That's about all I remember.

 

[DynaSoar]

Originally posted by sandman
powder,

Remember, most of us are BAR's and I believe the change came when most of us were "away" from the hobby and never really saw the change.

Or we never noticed it.

Yup. I remember there being some differences at different times, but if they didn't impact me, I didn't pay attention. Motors were far more plug-n-play back then.

Here's a link to a page about older motors. The owner might be a good person to ask: https://www.a3maq.qc.ca/Keith/Rockets/Vintage.htm


Look at the FSI F motors at the bottom. I just got nine of them, including some boosters. Imagine direct-staged F100s in an 8 ounce 2 stage bird.
POOF!gone.
Some are F7s, which can't lift anything, but make great sustainers for altitude. Darn shame they're all out of cert.

 

[shockwaveriderz]

powder: the info you are looking for may be in the RMR archives.....

use google groups to search for some of it.....there is tons of information from very old timers about the various motors..

https://groups.google.com/groups?hl=en&lr=lang_en&newwindow=1&safe=off&group=rec.models.rockets


as a last resort you might email Bob Kaplow as he probably has the most extensive model rocket motor collection and selection from "the day" or Mary Roberts at Estes.....

My first go around with rocketry was 1967-1973 but back then as a teenager I really didn't pay much attention to motor construction

good luck and if you find the answers please post the info for all of us to enjoy....

 

[powderburner]

You have some good suggestions and info.

DynaSoar, I also was more interested in launching them than studying them. I just remember being puzzled at the changes, wondering why.

If I can improve the accuracy of the data correlations by using more of these details, I will certainly post my results.

 

[DynaSoar]

Originally posted by powderburner
DynaSoar, I also was more interested in launching them than studying them. I just remember being puzzled at the changes, wondering why.

Like Shockie said, call Mary Roberts at Estes. She knows the motor history.

When you decide to burn them, let me know. I'm never going to get to use these FSI motors at any club launch, and I can't wait to see that much BP power.

 

[Bazookadale]

>I remember seeing a variety of motor case thicknesses on the basic 18mm motors but don't remember which ones or how thick. Does anyone have any notes on this?<

The motors from the original "Mabel" machine at Estes were .690 O.D. or 11/16"
and the I.D was .406 or 13/32" and they produced 1/4A through B motors with delay/ejection charges in this size, they also produced a C.8-0 but there was no room in the casing for a delay.In the mid -'60s Mabel 1 reached full capasity and 2 new machines were built, one of which was set up to use casings with an I.D of .500" . This allowed C motors with delay/ejection charges. If you check www.ninfinger.org you will see that these were first listed in the 1968 Estes and Centuri catalogs, although I believe they were phased in at least a year earlier.
They had the old style rounded nozzles and paper caps. '68 was also when they started using metric designations instead of English.The cone shaped nozzles were shown in the 1969 catalog and I remember ceramic caps coming in '70 or 71. For a while they continued to make 1/4A and 1/2A motors in the .406 casing, not sure when that was phased out

Dale Greene
www.spaar.org

 

[BobH48]

Originally posted by bazookadale
The motors from the original "Mabel" machine at Estes were .690 O.D. or 11/16" and the I.D was .406 or 13/32" ..... snip ...... For a while they continued to make 1/4A and 1/2A motors in the .406 casing, not sure when that was phased out

Dale Greene
www.spaar.org

I have a pack of A5-2's dated 7-28-71 that are still in the .406 casing. The .406 casing probably went out with the A5's