Rock-A-Chute Motors

[Gus]

Intact box of Rock-A-Chute motors with all the original contents.

Anyone have an idea of what year these might have been?

[shrox]

Intact box of Rock-A-Chute motors with all the original contents.

Anyone have an idea of what year these might have been?

1958?

[shockwaveriderz]

Welll at least Jan 1959, which is when Estes started manufacturing the Rock-A-Chutes for MMI.

EDIT
There an MMi ad iin 12/59 issue of American Modeler mag where they advertise 3 standard A4 motors for $0.98....

For this ad to appear in the 12/59 issue, it had to be available perhaps as much as 3-4 months earlier than the publication date

The last MMi ad where they are 3 for $1.50 appears in the 4/59 issue of AM, so that dates them to after 4/59 and before approx 10/59

These were most likely made in Vern's backyard in Denver Co. by Estes Enterprises

Terry Dean

[BEC]

The printing on those looks just like that on my late 1960s vintage Estes engines....so perhaps these are from the original Vern Estes-build engine making machine (AKA "Mabel")?

[Ltvscout]

Intact box of Rock-A-Chute motors with all the original contents.

Who'd you steal those from? :D

[Bazookadale]

The printing on those looks just like that on my late 1960s vintage Estes engines....so perhaps these are from the original Vern Estes-build engine making machine (AKA "Mabel")?

I have both an original Brown Rock-a-chute and an early Estes Rock-a-chute - those motors are clearly Estes

Willing to sell them? :chuckle:

[Gus]

Terry,

Thanks for the help. I figured probably pre-1960. I've never seen a picture of this style box. The only box I had seen previously was the yellow one. I'm amazed that the original motors came in three packs and included instructions, igniters, and parachute protectors, just like today.



Who'd you steal those from? :D
Scott,

Right place, right time. ;)n One in a million pure dumb luck.

[snaquin]

Intact box of Rock-A-Chute motors with all the original contents.

Anyone have an idea of what year these might have been?

What a find and in great condition too!

.

[Mark II]

"...with parachute wrappers..."

A K A recovery wadding. I kind of like MMI's terminology - on one level, "parachute wrappers" is a very specific, functional way of describing wadding (if you already know what it is). On another level, it is strikingly vague and euphemistic. (Huh? Parachute wrappers? Why would you need wrapping paper for the parachute?)

MarkII

[shrox]

We have an unfolded box in the display case, model rockets were referred to as model missiles then.

[mperdue]

Gus,

Those are extraordinarily dangerous! Ship them to me ASAP for proper disposal!

Mario

:)

[stefanj]

"...with parachute wrappers..."

A K A recovery wadding. I kind of like MMI's terminology - on one level, "parachute wrappers" is a very specific, functional way of describing wadding (if you already know what it is). On another level, it is strikingly vague and euphemistic. (Huh? Parachute wrappers? Why would you need wrapping paper for the parachute?)

MarkII

You might know this, but:

This wasn't wadding they were talking about. Way early on, parachutes were protected by a sort of folded paper cup with long "legs" that formed the sides. Plain paper, from everything I've read.

Ah, you can see them in one of the pictures, lower right side. The diagram printed on the outside sheet shows an assembled protector.

By the early '60s wadding replaced protectors.

[shrox]

You might know this, but:

This wasn't wadding they were talking about. Way early on, parachutes were protected by a sort of folded paper cup with long "legs" that formed the sides. Plain paper, from everything I've read.

Ah, you can see them in one of the pictures, lower right side. The diagram printed on the outside sheet shows an assembled protector.

By the early '60s wadding replaced protectors.

We have that in our display case too.

[Royatl]

The box I have (white with plain green printing) was probably from 1959, according to Vern (due to original type of casing tubes).

The fancier printing on your box was probably used from 1960 through at least 1964, as I've seen a Model Missiles ad in a 1964 Boys Life with that design

[Mark II]

You might know this, but:

This wasn't wadding they were talking about. Way early on, parachutes were protected by a sort of folded paper cup with long "legs" that formed the sides. Plain paper, from everything I've read.

Ah, you can see them in one of the pictures, lower right side. The diagram printed on the outside sheet shows an assembled protector.

By the early '60s wadding replaced protectors.No, I didn't know that! Thanks for the info; now it makes sense.

MarkII

[Gus]

The box I have (white with plain green printing) was probably from 1959, according to Vern (due to original type of casing tubes).

The fancier printing on your box was probably used from 1960 through at least 1964, as I've seen a Model Missiles ad in a 1964 Boys Life with that design
Roy,

Will you snap some pics and post them on this thread? I tried to do some research before posting here and I came up with zero photos of the old boxes.

I'm on my way out of town (to the Capitol Cup) but when I get back I will post scans of all the paperwork inside the box.

Steve

[shockwaveriderz]

Gus, could you photo the little blue strip of paper and the parachute protector?

Terry Dean

[shockwaveriderz]

Gus here are some photos:

The first shows the original 6-pak box with Brown Manufactured Rock-A-Chutes while the 2nd photo shows Roy's Estes Enterprises Rock_A_Chutes in the same 6 pak box...


Dale windsor has a pic showing your 3-pak box and some 6 pak boxs:

http://www.dalescience.info/rocket/page25/page21/page53/page53.html

Terry Dean

[Gus]

Terry,

Thanks for posting the pics. When I get home I'll scan all the pieces and post them.

[Gus]

OK, here are scans of the box and contents.

1. Scan of box and all the contents
2. Box Front, including open top and bottom
3. Box back
4. Box sides

[Gus]

Box Contents:

1. Motor Mount Notice - Front
2. Motor Mount Notice - Back (actually a price list for MMI items)
3. Rock-A-Chute Instruction Sheet - Front
4. Rock-A-Chute Instruction Sheet - Back
5. Rock-A-Chute Parachute Wrapper (3 of these were in the box)
6. Rock-A-Chute electrical ignitors (this card has 3 ignitors taped to it)
7. Rock-A-Chute motor ignitor retainer stickers

[Gus]

Motor nozzle comparison:

Rock-A-Chute A motor on left.

Centuri A8-3 on right.

Note how thick the wall is on the Rock-A-Chute.

[wilsotr]

"Designed for boys over 12" .... my how times have changed. :)

[stefanj]

Thank you for the great scans!

We've all seen scans of catalogs from the early days, but little things like motor instruction sheets have been neglected.

I'd love to see Minimax motor instructions, for example.

[BEC]

Motor nozzle comparison:

Rock-A-Chute A motor on left.

Centuri A8-3 on right.

Note how thick the wall is on the Rock-A-Chute.

I have some Estes 1/4A and 1/2A engines with November 1967 date codes that have nozzles that look just like the Rock-A-Chute example. I also have three June 1968 1/4A3-4s that have the thick casing walls but a much flatter nozzle face as in the Centuri example above (or current Estes engines). It's also intersting just looking at them that the 1967 engines are in English units (1/2A .8-0S, for example) but the 1968-ers are Metric.

[Bazookadale]

I have some Estes 1/4A and 1/2A engines with November 1967 date codes that have nozzles that look just like the Rock-A-Chute example. I also have three June 1968 1/4A3-4s that have the thick casing walls but a much flatter nozzle face as in the Centuri example above (or current Estes engines). It's also intersting just looking at them that the 1967 engines are in English units (1/2A .8-0S, for example) but the 1968-ers are Metric.

The Rock-a-chutes and Estes motors up to the mid '60s were made on the original Mable machine which used casings with an ID of .406". tI was Mable 2 or maybe Mable 3 that went to the .500" thin wall casing. Also the mable 1 motors had simple rounded nozzles.

As a kid I always wondered why .406" and not just .400 - it was years 'till I figured out .406 is 13/32"

[Royatl]

Motor nozzle comparison:

Rock-A-Chute A motor on left.

Centuri A8-3 on right.

Note how thick the wall is on the Rock-A-Chute.

All motors were that thick (.406" id) before 1968. Also, the nozzles all had gently curving, "horn bell" shapes (B14 was a bit different) until a little later (I've got a couple of .5" id motors from 1968 that have bell nozzles)

[Carl@Semroc]

As a kid I always wondered why .406" and not just .400 - it was years 'till I figured out .406 is 13/32"...and .6875" is 11/16". In various places the casing size is listed as .690" and .688". For some reason, we ordered .688", maybe because NE used three decimal places.

[shockwaveriderz]

great p[ic Gus. Notice the 4629 E. Cedar Ave Denver Co address. That just happens to be the location of Dick Keller's Dad's House , Skip Keller, which is where MMI moved to the basement after GHS was removed as President on July 30 1959.

Prices were much reduced over initial prices to move inventory out the door.

thanks

Terry Dean

[Gus]

...and .6875" is 11/16". In various places the casing size is listed as .690" and .688". For some reason, we ordered .688", maybe because NE used three decimal places.
Carl,

Could you fill in a bit of the technical and business history for us?

When Vern started was he just using standard fireworks casings? What were the technical requirements in terms of strength? Did he (and you at Semroc) have to have these specially made or was there some company churning them out for some other purpose? When you got into motor making was there more than one place for you to get casings? I know how hard the current casings are if you try to cut through (an empty) one. Are they made the same way today they were back then?

Thanks,

Steve

[stefanj]

FYIage:

When I got my very first orders from Estes -- Fall 1970, Spring 1971 -- the motors came with a little slip of paper describing improvements in motor design. The only specific I recall was the use of more clay parts . . . meaning the ejection charge cap, I suppose. I guess they wanted to explain the big changes in the motors' appearance.

I don't recall getting any of the narrow-ID motors back in the day. Most of the motors I purchased for the first years were Centuri and MPC, from local hobby shop and a hardware/variety store.

I have a dozen or so of the early motors now, given to me by a manager who was big into the hobby back in the late '60s.

[Royatl]

FYIage:

When I got my very first orders from Estes -- Fall 1970, Spring 1971 -- the motors came with a little slip of paper describing improvements in motor design. The only specific I recall was the use of more clay parts . . . meaning the ejection charge cap, I suppose. I guess they wanted to explain the big changes in the motors' appearance.

I don't recall getting any of the narrow-ID motors back in the day. Most of the motors I purchased for the first years were Centuri and MPC, from local hobby shop and a hardware/variety store.

From '68 to about late '70 they still used the paper ejection cap they used from the beginning. In the early photos of Mabel, you can see the big roll of paper that the caps were punched from.

The lower power 18mm motors (A5, 1/2A6, and 1/4A3) were apparently still made on Mabel I for awhile and so still came with .406" IDs and so would have still been available into the '70's.

[Shreadvector]

FYIage:

When I got my very first orders from Estes -- Fall 1970, Spring 1971 -- the motors came with a little slip of paper describing improvements in motor design. The only specific I recall was the use of more clay parts . . . meaning the ejection charge cap, I suppose. I guess they wanted to explain the big changes in the motors' appearance.

I don't recall getting any of the narrow-ID motors back in the day. Most of the motors I purchased for the first years were Centuri and MPC, from local hobby shop and a hardware/variety store.

I have a dozen or so of the early motors now, given to me by a manager who was big into the hobby back in the late '60s.

IIRC, back in that timeframe, the A8 and B6 and C6 motors were in the new thin wall casings and the 1/4A3, 1/2A6, A5 and B4 were in the thick walled casings. Both casing types remained in production through the transition from loose black powder ejection charges with a paper cap (leaky) to the modern clay cap.

[Carl@Semroc]

Carl,

Could you fill in a bit of the technical and business history for us?

When Vern started was he just using standard fireworks casings? What were the technical requirements in terms of strength? Did he (and you at Semroc) have to have these specially made or was there some company churning them out for some other purpose? When you got into motor making was there more than one place for you to get casings? I know how hard the current casings are if you try to cut through (an empty) one. Are they made the same way today they were back then?

Thanks,

SteveI think his first ones may have been standard fireworks casings, but he quickly moved to New England Paper Tube Company. They made them from Virgin Kraft high burst strength paper . I am not sure the exact specs, but it is around 5kPa, almost two times that of standard Kraft paper. Vern needed it on Mable I because there was not a supporting metal sleeve to keep the engine casing from swelling under the high pack pressure. Later Mables used metal sleeves so the casings could be thinner.

Tom Kennedy is still at New England and still talks fondly of Vern and Gleda and the "old days." There was a major disagreement between Estes Industries and New England over trade secrets concerning the engine casings in late 1997. Estes sued (http://www.fundinguniverse.com/company-histories/Centuri-Corporation-Company-History.html) and lost. Tom related that NE was making the same tubes before Estes approached them and the judge agreed. They refused to sell Estes any tubes after that lawsuit. Estes has used Sonoco (I believe) as a supplier since then. It is ironic that Semroc used Sonoco for a short time before discovering NE. We changed over to NE exclusively because their tubes were superior to Sonoco. Today, the tubes from Sonoco are much better than they were in the late 60's, but I still have a fondness for NE!

Tubes from New England are still made the same way and to the same standards they were 50 years ago. I was amazed at their precision and the way the last wrap was ground to hide the outside seam.

[mojo1986]

I think his first ones may have been standard fireworks casings, but he quickly moved to New England Paper Tube Company. They made them from Virgin Kraft high burst strength paper . I am not sure the exact specs, but it is around 5kPa, almost two times that of standard Kraft paper. Vern needed it on Mable I because there was not a supporting metal sleeve to keep the engine casing from swelling under the high pack pressure. Later Mables used metal sleeves so the casings could be thinner.

Tom Kennedy is still at New England and still talks fondly of Vern and Gleda and the "old days." There was a major disagreement between Estes Industries and New England over trade secrets concerning the engine casings in late 1997. Estes sued (http://www.fundinguniverse.com/company-histories/Centuri-Corporation-Company-History.html) and lost. Tom related that NE was making the same tubes before Estes approached them and the judge agreed. They refused to sell Estes any tubes after that lawsuit. Estes has used Sonoco (I believe) as a supplier since then. It is ironic that Semroc used Sonoco for a short time before discovering NE. We changed over to NE exclusively because their tubes were superior to Sonoco. Today, the tubes from Sonoco are much better than they were in the late 60's, but I still have a fondness for NE!

Tubes from New England are still made the same way and to the same standards they were 50 years ago. I was amazed at their precision and the way the last wrap was ground to hide the outside seam.

WOW, really interesting stuff, Carl. Thanks for posting this.

Joe

[Gus]

Carl,

Thanks for the info. That filled in some big gaps in my understanding of the early motors.

Opening the Rock-A-Chute box was a real surprise to me. The contents of the box are almost exactly what you find in a Walmart-version Estes motor pack today. 3 motors, igniters, igniter holders, and parachute protection. I'd love to see similar scans of the earlier version Rock-A-Chute boxes and contents.

[Shreadvector]

IIRC, back in that timeframe, the A8 and B6 and C6 motors were in the new thin wall casings and the 1/4A3, 1/2A6, A5 and B4 were in the thick walled casings. Both casing types remained in production through the transition from loose black powder ejection charges with a paper cap (leaky) to the modern clay cap.

MPC A3 and B3 motors used the thick walled casing as well.

[blackshire]

Carl,

Could you fill in a bit of the technical and business history for us?

When Vern started was he just using standard fireworks casings? What were the technical requirements in terms of strength? Did he (and you at Semroc) have to have these specially made or was there some company churning them out for some other purpose? When you got into motor making was there more than one place for you to get casings? I know how hard the current casings are if you try to cut through (an empty) one. Are they made the same way today they were back then?

Thanks,

Steve

According to G. Harry Stine, those 0.690" diameter motor cases were an existing case size that was used for a firework device called the "Buzz Bomb," which I believe was a helicopter-type piece with a report.

[blackshire]

"...with parachute wrappers..."

A K A recovery wadding. I kind of like MMI's terminology - on one level, "parachute wrappers" is a very specific, functional way of describing wadding (if you already know what it is). On another level, it is strikingly vague and euphemistic. (Huh? Parachute wrappers? Why would you need wrapping paper for the parachute?)

MarkII

The First Edition of G. Harry Stine's "Handbook of Model Rocketry" has the plan & pattern for the original-design parachute wrappers, which were cruciform in shape, rather like a Maltese Cross. Two opposing arms of the cross had the angled cuts toward the center (like the cuts in the newer wrapper design that Gus posted).

I once tried home-made cruciform parachute wrappers, and they worked very well. If the parachute wrappers are made of fire-proofed typing paper or computer printer paper (see below for a fire-proofing solution recipe), they are just as safe as commercially made wadding. Here is the recipe (from a July 1961 "Popular Science" article about tissue paper model hot air balloons):

Water..............................4 ounces
Borax...............................60 grains
Boric acid.........................28 grains
White glue....................3 or 4 drops

Just saturate the paper by flowing this solution over it, then let the paper dry.

[Mark II]

It's also intersting just looking at them that the 1967 engines are in English units (1/2A .8-0S, for example) but the 1968-ers are Metric.Exactly. 1968 was when Estes changed over from using English units to metric units for their motor designations. The motor chart in the 1968 Estes catalog cross-references their motors bearing the new metric designations with their previous English equivalents. I'm not sure when NAR S&T began using metric units for motor designations, but I believe it was a couple of years before that and that Estes took awhile to change over.

MarkII

[stefanj]

Exactly. 1968 was when Estes changed over from using English units to metric units for their motor designations. The motor chart in the 1968 Estes catalog cross-references their motors bearing the new metric designations with their previous English equivalents. I'm not sure when NAR S&T began using metric units for motor designations, but I believe it was a couple of years before that and that Estes took awhile to change over.

MarkII

My working theory is that they waited until the motor redesign / new Mabel to introduce the Metric-themed motor codes.

I remember having a few A5 motors back in the day, but don't remember them being "different." I might have just not noticed. They (and B4 motors) were specialty items, in that you didn't see them in the hobby shops and variety stores that my friends and I bought motors from.

[blackshire]

I remember the A5-2, which was one of the recommended motors for the Estes Falcon boost-glider. Is the B4 you're referring to the plugged static test motor B4-0(P) that was listed in their catalogs up until about 1969 or 1970?

[stefanj]

I'm speaking B4 generically. B4-2, B4-4, etc. There was even a B4-0 at one point.

The B4-x probably started out as a relabeled B.8-x, and the A5-x as a relabeled A.8-x. Old motor technology items.

Eventually the B4-x was redesigned to use the newer motor technology, and the A5 dropped.

[Gus]

Reviving this old thread to ask a new question.

MMI also produced “Super B6” Rock-A-Chute motors, as well as separately labeled and distinctly colored booster and sustainer motors. All of these were produced by Vern.

Does anyone have any idea how these were packaged? I’ve never seen any packaging other than the original green label box for the Brown Manufacturing motors or the colorful box for the A4 motors that appears at the beginning of this thread?

Thanks,

Steve

[shockwaveriderz]

Reviving this old thread to ask a new question.

MMI also produced “Super B6” Rock-A-Chute motors, as well as separately labeled and distinctly colored booster and sustainer motors. All of these were produced by Vern.

Does anyone have any idea how these were packaged? I’ve never seen any packaging other than the original green label box for the Brown Manufacturing motors or the colorful box for the A4 motors that appears at the beginning of this thread?

Thanks,

Steve

don't know about packaging but:
A4 = A.8-3
Super Type B6 = Type B.8-4

[shockwaveriderz]

Reviving this old thread to ask a new question.

MMI also produced “Super B6” Rock-A-Chute motors, as well as separately labeled and distinctly colored booster and sustainer motors. All of these were produced by Vern.

Does anyone have any idea how these were packaged? I’ve never seen any packaging other than the original green label box for the Brown Manufacturing motors or the colorful box for the A4 motors that appears at the beginning of this thread?

Thanks,

Steve

don't know about packaging but:
A4 = A.8-3
Super Type B6 = Type B.8-4

the A4 and Super B6 where 2 of the 4 motors used at NARAM-1 in July 1959.

That's an Estes Enterprises manufactured MMI Rock-A-Chute. These "Super" type B6 were introduced to the public by "Sam, the Spaceman" with a MMI ad in American Modeler magazine in July 1959.

[ghrocketman]

I still have a bunch of thick-walled A5 motors in both lengths.
The B4-0 was only available as a plugged B4-0(P).

[Gus]

don't know about packaging but:
A4 = A.8-3
Super Type B6 = Type B.8-4

the A4 and Super B6 where 2 of the 4 motors used at NARAM-1 in July 1959.

That's an Estes Enterprises manufactured MMI Rock-A-Chute. These "Super" type B6 were introduced to the public by "Sam, the Spaceman" with a MMI ad in American Modeler magazine in July 1959.

Terry,

Thanks so much for posting that! I've never seen that ad. May have to find a physical copy.

Steve

[BEC]

...and almost off topic: My maternal grandparents lived at 4106 So. Cherokee street for many many years. Unitl I looked at that ad, I had no idea MMI was so close to a place I went to every Saturday night when we lived in Denver and as often as practical after my family moved to New Mexico.....

Of course, I was coming up to my fourth birthday when that ad ran, so wouldn't have noticed/cared about MMI being that close, I suppose.

But we did, back then, live next door to a hobby shop on the other side of the city. I still have my first #1 X-Acto knife purchased there for 60 cents.

Now, back to MMI motors.