Yes, the manual hand-rammed methods in the Teleflite book could be rather involved. I was put off trying them by the first step given in the book, which was the construction of a steel plate "explosion shield."

Sugar rockets aren't quite as hazardous to make as black powder motors, and they lend themselves to core-burner grains. (It's really a necessity with sugar motors due to the propellant's lower specific impulse.)

The sulfur in the BP acts as a binder, but the MSDS I found with a case of motors indicated that a small amount of dextrin was added which would also be a binder

I have also been wrong in the past - once in 1973 and again in 1994!

We do have an expert on the subject that has firsthand knowledge on making Estes engines that is a regular here on YORF. Maybe one day he'll speak up and shed some light on our many motor questions. ;) (Note I used engine and motor in the same paragraph. heh)

Anyhow, he may also have signed some agreeement when he retired that does not allow him to speak about the manufacturing process for all I know.

Yes, I believe it was dextrin, I can't seem to find the pdf I had of that. A Google search shows that it is used as a binder in pyrotechnics.

The blast shield did discourage me from trying it my attached Garage!

Not that I could think of anyway to do it safely, other than the way it's done by manufacturers.

There is a thread or threads here on YORF in which we all contributed real or perceived manufacturing methods for the original original b16-b3-b14 and the later variations of the B14 to B8 transition, along with historical info and pics.


What follows is from memory and email conversations but the "O-O" b16-b3-b14 was actually just a B4 which has a wider core than a B6 that then had an approx. .25-.375 length cylinder shaped smaller core in it. If you look at the old Estes catalogs you will see pics of elongated cores running 3/4 "of the way up the grain; this was misinformation primarily to fool potential rival companies from copying Estes trade secrets.

So the "O-O" B14 started our life on a Mabel as a B4 and was then drilled by a machine designed invented by Vern Estes. I'm not at liberty to go into the exacting details of the size and type of drill used,etc. Let's just say it wasn't simply just a twist drill. Vern did numerous tests varying drill bit types and rpm's to get the "sweet spot"....

So the "O-O" b14 was a semi-automated 2 step process.....


This 2 step process resulted in periodic explosive events so later B14's that evolved into the B8's later were all made from fully formed mandrels in Mabels.

I think "O-O" B14 could probably be made to day fully automated, using a combo cylinder-coned shaped mandrel, but if that was true Estes probably would have already done it.

I've never been privy to how abrasive the hydraulically pressed fine black powder is on the tooling.....but i'm sure it has to be replaced or retrofitted on a more or less regular basis as the fine black powder being pressed at the pressures they are on automated runs over time had to be very abrasive, so the tooling has to be made of some pretty hard stuff.

I would guess for insurance purposes they have made the business decision to let B14's Rest In Peace.

hth

Terry Dean

I personally have original examples of late 60's/early 70's Centuri B14-7's and Estes B14-0's that have cores so narrow that they MUST have been drilled. Any pintle that deep and small in diameter would most likely break under the ramming pressure.
The drilled core is approximately .0625 (1/16") in diameter and quite deep. The nozzle appears to be a standard "B4" profile nozzle diameter and shape.

Thanks for chiming in Terry. Your post confirms my suspicions. Maybe we will see a B8-x again some day, or a C5-0, but I think B14's are gone but not forgotten.

Sulfur does not act as a "binder" in EstesBP rocket engines. There is no need for an additive binder in Estes BP engines, because they press to approx 1.7 g/cc ..at these pressures the fine particles of black powder ie KNO3/S/C undergo a plastic deformation process...ie they become somewhat plasticized and they flow freely into and with one another.

http://en.wikipedia.org/wiki/Plasticity_%28physics%29

Sulfur does act as a pyrolant in black powder ie as an ignition promoter.




As far as Dextrin being used in Estes engines, I too have seen that MSDS..... I once asked a source if Dextrin was every used in the Estes manufacturing process as a binder or anything else..... and I was told no. It may show up on the that old MSDS because it was used a a burn rate modifier in the delay train...... but it was not used in the actual propellant.

If you look at modern day MSDS from the 80's forward you will see no mention of dextrin. Dextrin is a well know binder used by some who make BP pyrotechnic skyrockets. It will also slow down the burn rate. This is favorable in skyrockets as they are have full top to bottom cores and a slower BP is required.



It is my understanding the the large FGH Rocketflite BP engines actually used a water based elastomer as a binder but this was required because of their sheer size and their large cores.... the binder made the pressed BP grains somewhat rubbery so they wouldn't crack and they would adhere better to the casings.

HTH

Terry Dean

Now that we know all about B14's, and have a good idea on the Mini-Max's, Does anyone know how FSI cored/pressed their motors?