Ye Olde Rocket Forum

Ye Olde Rocket Forum (http://www.oldrocketforum.com/index.php)
-   SVDT - Semroc Virtual Design Team (http://www.oldrocketforum.com/forumdisplay.php?f=20)
-   -   Bt-30 (http://www.oldrocketforum.com/showthread.php?t=2549)

Carl@Semroc 12-08-2007 10:21 PM

Bt-30
 
I have a quote from the original manufacturer of the parallel wound BT-30's (after Gleda, that is.) The order is pending a sample of an original tube to match the paper. They do not still have those records, but know they did make them for a short time.

If anyone can supply a small piece of an original BT-30, I can not promise to get it back, but I can provide many newer replacements.

We are working on an exact replica of the original Scout that was packaged in engine mailing tubes in the earliest days of Estes for Vern and Gleda to hand out at the next NARAM to commemorate their 50th anniversary in model rockets.

dwmzmm 12-09-2007 12:10 AM

That's great news, Carl. I got a balsa nosecone from BMS some time ago that's the same
as that for the Astron Scout. I was thinking, whenever I can get around to building a clone
of the model, of handwrapping paper around a standard BT-20 tubing to simulate the BT-30.
I've been wanting to build a clone of the Astron Scout to "replace" my original Estes kit that
got lost just as I was returning to the hobby in January 2004 (at Rushing Park, near Katy,
TX - Challenger's regular launch site) :( :mad: . It was painful to lose that model after having it for some 35 years....

sandman 12-09-2007 11:44 AM

I have one. I sent you a message on it.

kurtschachner 12-09-2007 02:04 PM

Quote:
Originally Posted by sandman
I have one. I sent you a message on it.


Ya, I have quite a lot too. Let me know if you need any more.

What I don't have is any BT-40. Maybe that could be your next offering :D

Mark II 12-09-2007 06:42 PM

Quote:
Originally Posted by kurtschachner
Ya, I have quite a lot too. Let me know if you need any more.

What I don't have is any BT-40. Maybe that could be your next offering :D

Semroc lists BT-40 in their online catalog. They have also had BT-30 for awhile, but spiral-wound, not parallel. I like cloning the old designs, so I've been using plenty of the BT-30. :)

Mark K.

SEL 12-09-2007 07:56 PM

Estes BT-30
 
Quote:
Originally Posted by kurtschachner
Ya, I have quite a lot too. Let me know if you need any more.

What I don't have is any BT-40. Maybe that could be your next offering :D


Hi Kurt -

If you're interested in selling a couple or four bt-30's I'd be interested in buying them.
I have a few projects in the works that I'd like to use the original's on.

Sean

kurtschachner 12-09-2007 08:40 PM

Quote:
Originally Posted by Mark II
Semroc lists BT-40 in their online catalog. They have also had BT-30 for awhile, but spiral-wound, not parallel. I like cloning the old designs, so I've been using plenty of the BT-30. :)

Mark K.


Ya, I am assuming it is spiral wound BT-40. IIRC Estes never made parallel-wound BT-40, it was only the leftover MMI stock, right?

Ltvscout 12-09-2007 08:51 PM

Quote:
Originally Posted by kurtschachner
Ya, I have quite a lot too. Let me know if you need any more.

I knew you had a bunch and I was going to volunteer you after Carl made the post, but I figured I'd wait and let you do it. ;)

kurtschachner 12-09-2007 09:12 PM

Quote:
Originally Posted by Ltvscout
I knew you had a bunch and I was going to volunteer you after Carl made the post, but I figured I'd wait and let you do it. ;)


Apparently my "bunch" has dwindled. I went downstairs and did an inventory, and found I had less than I thought.

I remember now that I gave away a couple of pieces as door prizes to the Christmas party (?), plus I built a Scout and two Sprites.

Ltvscout 12-09-2007 09:16 PM

Quote:
Originally Posted by kurtschachner
I remember now that I gave away a couple of pieces as door prizes to the Christmas party (?), plus I built a Scout and two Sprites.

Ah yes, that was a number of years ago that you gave those as prizes for the contest you put together.

Mark II 12-09-2007 11:31 PM

Quote:
Originally Posted by kurtschachner
Ya, I am assuming it is spiral wound BT-40. IIRC Estes never made parallel-wound BT-40, it was only the leftover MMI stock, right?

No, when I mentioned the part about them only having a spiral-wound version, I was referring to Semroc's BT-30.

I started ordering from Estes in 1967, but I don't recall ever seeing the engine mailing tubes (aka BT-40) during that time. My orders used to come in a long box - almost exactly like my orders from Semroc do! ;) - and the engines would come lined up end to end and rolled up in some newspaper, and then packaged in their own little parcel post box, as I recall.

I'm not 100% sure about this, though; it was a long time ago, I only had about 3 or 4 orders with them altogether (didn't have much money then) before taking a 30+ year hiatus from the hobby, and nothing that I had from that era has survived (my folks threw away all of my rocket stuff - including live engines! :eek: - when I went off to college). :(

Mark K.

Ltvscout 12-10-2007 08:04 AM

Quote:
Originally Posted by Mark II
No, when I mentioned the part about them only having a spiral-wound version, I was referring to Semroc's BT-30.

I started ordering from Estes in 1967, but I don't recall ever seeing the engine mailing tubes (aka BT-40) during that time. My orders used to come in a long box - almost exactly like my orders from Semroc do! ;) - and the engines would come lined up end to end and rolled up in some newspaper, and then packaged in their own little parcel post box, as I recall.

I'm not 100% sure about this, though; it was a long time ago, I only had about 3 or 4 orders with them altogether (didn't have much money then) before taking a 30+ year hiatus from the hobby, and nothing that I had from that era has survived (my folks threw away all of my rocket stuff - including live engines! :eek: - when I went off to college). :(

Mark K.

Mark,

The engine mailing tubes and the BT-40 were two different animals. The BT-40 was from what I recall leftover stock from MMI. I have some scratch-built rockets here that I bought off of eBay six or seven years ago that have BT-40 tubes and those old, rubber nose cones. This tube had an inside diameter of .765". They had a balsa cone, a plastic skyrocket cone (fit over the outside of the tube) and two rubber cones available for this tube. The BT-40 size derived from the skyrocket size tube if I'm not mistaken.

The engine mailing tubes were much larger in diameter and much thicker-walled. Estes only offered one cone for the engine mailing tubes. That was the BNC-MTD. This tube had an inside diameter of .937".

kurtschachner 12-10-2007 08:12 AM

Quote:
Originally Posted by Ltvscout
Mark,

The engine mailing tubes and the BT-40 were two different animals. The BT-40 was from what I recall leftover stock from MMI. I have some scratch-built rockets here that I bought off of eBay six or seven years ago that have BT-40 tubes and those old, rubber nose cones. This tube had an inside diameter of .765". They had a balsa cone, a plastic skyrocket cone (fit over the outside of the tube) and two rubber cones available for this tube. The BT-40 size derived from the skyrocket size tube if I'm not mistaken.

The engine mailing tubes were much larger in diameter and much thicker-walled. Estes only offered one cone for the engine mailing tubes. That was the BNC-MTD. This tube had an inside diameter of .937".


Yes, this is correct. BT-40 is pretty similar to BT-30, much smaller than the mailing tubes.

Carl@Semroc 12-10-2007 08:21 AM

Quote:
Originally Posted by Ltvscout
The engine mailing tubes were much larger in diameter and much thicker-walled. Estes only offered one cone for the engine mailing tubes. That was the BNC-MTD. This tube had an inside diameter of .937".
As Scott said, the ID was .937". The OD was 1.002" which meant most of the balsa nose cones for it had a flat spot since the balsa was 1" x 1". One of the biggest problems with convolute (parallel) wound tubes is their "roundness" which is not as good as spiral wound tubes and the fact that they are different thicknesses around the inside of the tube.

I had always wondered why there was a seam on the inside of a convolute tube and the outside had very little seam. I thought the paper was tapered on the outside edge, but someone recently told me that the final tube was sanded smooth on the outside.

Mark II 12-10-2007 09:02 AM

Quote:
Originally Posted by Ltvscout
Mark,

The engine mailing tubes and the BT-40 were two different animals. The BT-40 was from what I recall leftover stock from MMI. I have some scratch-built rockets here that I bought off of eBay six or seven years ago that have BT-40 tubes and those old, rubber nose cones. This tube had an inside diameter of .765". They had a balsa cone, a plastic skyrocket cone (fit over the outside of the tube) and two rubber cones available for this tube. The BT-40 size derived from the skyrocket size tube if I'm not mistaken.

The engine mailing tubes were much larger in diameter and much thicker-walled. Estes only offered one cone for the engine mailing tubes. That was the BNC-MTD. This tube had an inside diameter of .937".

A-ha! My knowldege of early model rocket history is even sketchier than I thought! I had read about the old mailing tubes, and had also read about BT-40, and had assumed that they were the same thing. I stand corrected. In any event, back in the day I never saw either one.

BTW, when I went to build my Li'l Augie (EIRP-10) this summer, the plans called for cutting the augmenter tube out some mailing tube, by which I assumed they meant the engine mailing tube. I thought that I would need BT-40 for that, but it turned out to be the wrong diameter and I ended up using ST-10, which worked fine. Now you have cleared up that mystery for me. Thanks!

Mark K.

Doug Sams 12-10-2007 12:40 PM

Re: Li'l Augie
 
Quote:
Originally Posted by Mark II
BTW, when I went to build my Li'l Augie (EIRP-10) this summer, the plans called for cutting the augmenter tube out some mailing tube, by which I assumed they meant the engine mailing tube. I thought that I would need BT-40 for that, but it turned out to be the wrong diameter and I ended up using ST-10, which worked fine. Now you have cleared up that mystery for me. Thanks!.
I used BT-50 for mine. I think anything in the 1" vicinity will work well. FWIW, I epoxied a tin foil liner to the augmenter tube. It has held up well so far although I don't fly it often.

With the extra motor in it, space for the recovery system is quite limited. I end up stuffing the shock cord into the hollow plastic nosecone.

Doug

Bob H 12-10-2007 09:34 PM

Quote:
Originally Posted by Mark II
- and the engines would come lined up end to end and rolled up in some newspaper, and then packaged in their own little parcel post box, as I recall.

The little boxes would hold 9 tubes of engines and that's the way I always got them. Supposedly, that was the maximum number of engines that could be mailed in one box.

They never came rolled in newspaper. They were always in the mailing tubes. You could buy single motors so maybe if you were only ording 1 or 2 of a specific type they would wrap them in paper. I always ordered them in quantities of 3 because they were cheaper if you bought 3.

Whenever I ordered motors, I would order enough to fill one of the boxes. I still have one of those boxes and the postage sticker is from September, 1969 and it cost $.85 to ship.

Mark II 12-10-2007 10:12 PM

Quote:
Originally Posted by Bob H
They never came rolled in newspaper. They were always in the mailing tubes. You could buy single motors so maybe if you were only ording 1 or 2 of a specific type they would wrap them in paper. I always ordered them in quantities of 3 because they were cheaper if you bought 3.

You're right. I think that the most engines that I ever included in an order was 6 - 2 each of three different kinds. Even with the quantity discount, my budget was too meager to allow me to order any one kind of engine in quantities of three. Back then, ordering 27 engines at once would have just boggled my mind. These days, of course, I have a slightly different perspective, and regard a quantity order like that as being merely astonishing. :eek:

Mark K.

Bob H 12-11-2007 06:44 AM

Quote:
Originally Posted by Mark II
You're right. I think that the most engines that I ever included in an order was 6 - 2 each of three different kinds. Even with the quantity discount, my budget was too meager to allow me to order any one kind of engine in quantities of three. Back then, ordering 27 engines at once would have just boggled my mind. These days, of course, I have a slightly different perspective, and regard a quantity order like that as being merely astonishing. :eek:

Mark K.
I was a little older when I discovered model rocketry so I had a part time job at the local ice cream shop. I was probably pulling in $20 a week and I mowed lawns in the summer also. So by the time I used up my last order of engines, I had saved up enough to buy another box.

By 1969 (the box that I still have), I was out of High School and had a full time job and still living at home so rocketry money wasn't a problem. Heck, I bought a brand new Z28 Camaro in 1969 and the car payments were only $55 a month.

Ltvscout 12-11-2007 08:05 AM

Quote:
Originally Posted by Bob H
Heck, I bought a brand new Z28 Camaro in 1969 and the car payments were only $55 a month.

Cool! Did it have the high output 327 small block in it?

My dad was new car manager of a large Chevy dealer here back then. He had a '69 Z28 as a demo that was all tricked out and custom painted. I still remember cruising around in that thing. He'd let me shift it from the right seat. I was all of seven years old. :D

Bob H 12-11-2007 09:08 AM

1 Attachment(s)
Quote:
Originally Posted by Ltvscout
Cool! Did it have the high output 327 small block in it?
It had a small block 302. It was a special made motor only for the Z28 to qualify for Trans Am racing so the motor had to be less than 305 CID.

It was the 327 block with a 283 crankshaft. The heads and the solid lifter camshaft were from the fuel injected Corvette. It had an aluminum high rise manifold with a huge Holly carburator.

You could get it with tubular headers that would be delivered in the trunk to be installed at the dealer but I didn't get those since my father, who had to co-sign the loan since I was under 21, was already freaking out that I was paying $3800 for a car. :eek:

The car has been completely restored and makes the car show circuit now. The current owner sends photos occasionally.

This thread has strayed OT a little bit. :rolleyes:

Ltvscout 12-11-2007 09:32 AM

Quote:
Originally Posted by Bob H
It had a small block 302. It was a special made motor only for the Z28 to qualify for Trans Am racing so the motor had to be less than 305 CID.

It was the 327 block with a 283 crankshaft. The heads and the solid lifter camshaft were from the fuel injected Corvette. It had an aluminum high rise manifold with a huge Holly carburator.

You could get it with tubular headers that would be delivered in the trunk to be installed at the dealer but I didn't get those since my father, who had to co-sign the loan since I was under 21, was already freaking out that I was paying $3800 for a car. :eek:

The car has been completely restored and makes the car show circuit now. The current owner sends photos occasionally.

This thread has strayed OT a little bit. :rolleyes:

Crap! You're right, I meant a 327 destroked with the 283 crank for a 302 CID. Those Camaros were awesome. I grew up around hot rods. My dad used to race at Great Lakes Dragaway in Union Grove, WI. My mom was always in to sports cars. When they met, she had a '60 Vette. She now cruises around in the Summer in a Toyota MR2 Spyder and a Pontiac Solstice. I remember in '73 my dad got my mom a Chevelle SS as a demo. My first car I bought in '78 was a '73 Chevelle SS. ;)

Ah, memories.

Mark II 12-11-2007 05:19 PM

Quote:
Originally Posted by Bob H
This thread has strayed OT a little bit. :rolleyes:

Did your Z28 have any BT-30 in it? :D

Mark K.

kurtschachner 12-11-2007 06:03 PM

Quote:
Originally Posted by Mark II
Did your Z28 have any BT-30 in it? :D

Mark K.


Like the earlier thread about NCW-1s that went for multiple pages, I think this one has wrung out pretty much everything there was to discuss about the subject ;)

Bob H 12-11-2007 08:09 PM

Quote:
Originally Posted by Mark II
Did your Z28 have any BT-30 in it? :D

Mark K.
Well, I did transport my Astron Sprite in it and that's made from BT-30.


All times are GMT -5. The time now is 03:59 PM.

Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.