Questions for Lee Piester
 

I was wondering what propellant(s) did he use in his Amateur Rocketry days. AND how did he come to know about them? Books? which ones? Magazine articles?

There is an early photograph of Lee with a young man named Laird Schroeder in the 65 HBMR...the rocket is the same one that was in Lee's Hobby store in Phoenix. Who was this person and what was their relationship during Centuri's earlier days? What happened to him?

Also something I've always been interested in was how did the Irv Wait Enerjet-8 with it's external thermalite fuse delay train evolve into the Enerjet's delay train/ejection charge?..... I'm particularly interested in the delay/ejection charge assembly.....who was it , that helped the design go from that old Carlisle inspired external fuse time delay ( see the Orv Carlisle patent for his toy rocket for reference) to the internal design of the Enerjet?

More questions I have is concerning the Coaster Motors.

In the 65 letter Lee talks about the motor making machinery coming from Euliss,TX to Phoenix. How about any description or comments on that machine(s)? Gang Rammers, Hydraulic cylinders? etc.

Also how about some information about the actual Centuri motor making machine. Where did he get the ideas for that? Had he seen the operation of the Estes MABEL and took it from there and basically cloned it or what?

The answers and elaboration on these questions would go a long way to filling in some of the gaps about motor design and manufacturing back in the early 60's to early 70's.

Terry,

I've never seen Lee participate in any forum or on any social media. But if you send a snail mail letter to him at Hobby Bench he might respond.

Hobby Bench
8058 N 19th Ave
Phoenix, AZ
85021

Steve

I seem to recall reading somewhere on a "Centuri Memories" thread that had a link to a video Lee did, that they were ZnS "Micrograin".

I'm assuming you've seen Lee's talk at the Museum of Flight, but just in case:

https://www.youtube.com/watch?v=DtfS540a5Ck

At one point he shows a glimpse of the blueprint of the regular motor machines, and mentions how it is a rotary index, makes a motor in 5 seconds, etc. so sounds like a Mabel, and looks like the machines MRC had and FSI found. And I'm not sure if it was in this video, but somewhere he mentions that the Coaster machinery was basically a gang press. And that they had to modify it due to un-even amounts of powder being deposited and causing none of the motors to be properly done.

after reading the Lee Piester interview, he states that he was cooking propellant in his kitchen with his wife, so that sounds to me like RCandy, ie Sugar Propellant. Nobody asks him the obvious questions:

How did Lee Piester discover or come to get into composite propellants? Did it come from one of your HS rocket mates? A fellow employee? or did he just read some books back then ?

I mean think about it. Where does one learn about composite propellants in the 55-60 timeframe? in the late 40's to mid-50's there was a lot of composite propellant work being done in the Army. I've read several books describing the history of composite propellants. But most of this stuff was top secret or just not really reported in the media at that time period.

John Rahkonen probably learned about composite propellants from his time in the Air Force in the mid 50's...

Irv Wait stated that he learned his while at Standard Oil(Indiana)

All my research shows that Sugar, Zn/S (micro grain) were most of the amateur rocketry fuels that was used back then.

You can liquify Zn/S but it was so dangerous and time-consuming, most people used it packed dry.

He talks about a 22 ft 220 lb propellant rocket that was launched in Yuma, Az.....what was that propellant?

That's a hell of a lot of propellant no matter what it was.

In the September 1962 issue of American Modeler magazine is a picture of Laird Schroeder and Leroy Piester, in G. Harry Stines column, Rocket Trails Page 10. see attached

G. Harry Stine in his article states, "propellant is a cast composite developed by Centuri's propellant expert, Laird Schroeder, 19 years old "



G. Harry seems to be implying that Centuri was going to come out with a cast composite propellant under the name of Mini-Max..... Folks this is September of 1962.

Is it possible that in late 1962 Centuri, ie Leroy Piester, was already planning on releasing cast composite model rocket motors , BUT under the name of Mini-Max, about 6 years or so before he actually did it with Irv Wait and his Enerjets?

Is it possible that Leroy Piester learned about composite propellant from this Laird Schroeder?

Who was Laird Schroeder? How did he and Leroy know each other?

The rocket in those photos is the same one Leroy Piester shows in this youtube video.

https://www.youtube.com/watch?v=U7sy_fLYSPg

see photo .

What propellant was used in it? or was it just Coasters?



I was hoping somebody that knows Leroy Piester might pass this along to him and ask him these questions.

thanks Roy.

I'll have to take a closer look at that youtube video. SO in essence it was a MABEL like machine with a rotary index table with multiple stations? And I was aware the Coasters were gang-pressed. And I was also aware of the calibration problem with the gang-press.
Can I assume the Mini-Max BP motors were gang-pressed? and not made on a MABEL like machine?

That's what I recall, that the Mini-Maxes were gang pressed. They figured out the problems with the gang press during the initial Mini-Max runs.

I also recall someone (Ed, Vern?) saying that when Damon had the Centuri machines shipped to Penrose, they wanted to incorporate them into Estes' system but could not, so they were scrapped, so they must've been fundamentally different in some way. Dave DelVecchio probably knows.