# help with some old ProDyne Inc motors

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#### Jerry Thompson

##### Member
I was into model rocketry during my high school years and even attended NARAM 6 and 7 in 1964 and 1965. I got back into it a little bit with my own kids 30 years ago and now I have grand kids interested. They found some of my old model rocketry supplies including some engines made by ProDyne Inc out of Utah. I think I bought them at NARAM 6 or 7 so they are 50 some years old. I have had them stored in a cool dry location all these years. They made a "Cyclone" and a "Hurricane" model. They are beautiful looking motors but I need help on the motor nomenclature. As an example they all seem to start with a BE lettering then numbers like 2.5-3 followed by a 0 which I assume is a booster or a a delay number like 4,5,6 etc So my question is what class motors are these? they are about 1 inch and 1 1/4 inch in diameter and have various lengths of 4-6 inches so I think they are too big to be B engines and I don't know what the BE stands for. I may test fire one of them to see if they still work. Here are some examples of the labels
BE - 2.5 -1 - 0
BE - 2.5 - 2 - 8
BE - 2.5 - 3 - 5
BE - 3.5 - 3 - 10
BE - 3.5 - 4 - 12

I just found and joined this forum so I hope I posted in the appropriate topic

#### dhbarr

##### Amateur Professional
2.5cm OD Cyclone / 3.5cm OD Hurricane IIRC.

The first number should be pounds of thrust and the second the delay.

#### Jerry Thompson

##### Member
2.5cm OD Cyclone / 3.5cm OD Hurricane IIRC.

The first number should be pounds of thrust and the second the delay.
so what is the middle number? sometimes is less then the first number and sometimes it is greater than the first number. Does the BE mean anything.

#### dhbarr

##### Amateur Professional
so what is the middle number? sometimes is less then the first number and sometimes it is greater than the first number. Does the BE mean anything.
Sorry: 2.5 & 3.5 are the diameters in cm ; 2nd is ( I think ) thrust in pounds ; 3rd is ( I think ) delay in seconds.

Maybe ProDyne made both BP & APCP motors? What does a light reveal in the nozzle? Any photos?

Regardless, please have someone video!

#### Nytrunner

##### Pop lugs, not drugs
TRF Supporter
+1 to pictures of the motors and video of any firings/flights!

#### Buzzard

##### Well-Known Member
This is the Prodyne E that I have in my collection. I do not recall the designation and it is buried in the ammo can of collectable motors. The nozzle is amazing. It is one of my favorites in my collection.

#### prfesser

##### Lifetime Supporter
TRF Lifetime Supporter
This is the Prodyne E that I have in my collection. I do not recall the designation and it is buried in the ammo can of collectable motors. The nozzle is amazing. It is one of my favorites in my collection.
Prodyne's owner--don't recall his name--mentioned that he pressed graphite nozzles into tubing at several thousand lb/in^2. Claimed they didn't pop out. But that nozzle looks like an ordinary clay+grog nozzle, tamped in like a fireworks motor.

#### Jerry Thompson

##### Member
I did understand your 2.5 and 3.5 meant cm. The cyclone is about 25 mm and the Hurricane is approx 29mm in diameter. Looking down the nozzle it appears grayish black. The booster engine looks gray on the top. I wonder if the number after the BE is some thrust amt in ? units and the next number could be thrust duration in seconds and the last number would be the delay. Could the B in BE stand for Black powder and the E for E class motor. I have tried to attach some photos of a few of these motors with a 24 mm Estes motor for comparison. Also price sheet when I ordered these.

#### Jerry Thompson

##### Member
This is the Prodyne E that I have in my collection. I do not recall the designation and it is buried in the ammo can of collectable motors. The nozzle is amazing. It is one of my favorites in my collection.
So you think this a class E motor. I am Still trying to figure out the nomenclature after the BE on the label. The nozzles do look great.They are very smooth and have a somewhat long curved aperture, and seem to be very hard. They do look more polished then the Estes nozzles.

#### CoyoteNumber2

##### Original San Diego High Power Rocketry
Sorry: 2.5 & 3.5 are the diameters in cm ; 2nd is ( I think ) thrust in pounds ; 3rd is ( I think ) delay in seconds.
Thrust in pounds - average, initial, peak?

#### Jerry Thompson

##### Member
Thrust in pounds - average, initial, peak?
I don't think the 2.5 and 3.5 refer to diameter because the Hurricane motor is approx 29 mm in diameter

#### prfesser

##### Lifetime Supporter
TRF Lifetime Supporter
Thrust in pounds - average, initial, peak?
I suspect you're right. The old Estes motors were A.8-3, B.8-4, B3-5 (coreburning), etc. I'd assume average thrust.

#### Lawndart

##### Well-Known Member
From a post back in 2008 on another forum:

As far as Prodyne was concerned they offered D2.5/D3.5 ( D11/D16), E2.5/E3.5( E11/E16) and F2.5/F3.5 (F11/F16) BP motors that used a hi-temp plastic casing and these ranged in size from 4-7.125" in length with an OD of 1.0"and an ID of 0.810 for the Cyclones and 3-6.0" x 1.125" OD x 1.0" ID .

The F11's had an Total Impulse of 45.4Ns while the F16 was 53 Ns, so they were barely an F. These were low thrust long burn (4.0 sec burn time for the F11/F160, had a propellant mass of approx. 2.3 oz, with an Isp of 80-85 sec.

The Cyclones had a a nozzle core of .01875, recessed .01875 into the casing., while the Hurricanes, had a nozzle diameter of .234" . These were ALL semi-core end burners like Estes end burners. I might add that the Cyclone core dimension are the exact same core dimension of the old B14 motor. hmmmmm....

The Cyclones had a peak thrust of 4.25 lbs(19N) and a sustainer thrust of 2 lb(9N).

The Hurricane's were the D,E,F 3.5 while the Cyclone's were the D,E,F 2.5

terry dean
nar 16158​

#### Jerry Thompson

##### Member
Thanks for finding the above info, so I am assuming I have E motors. So does the 2.5 designate average thrust of 2.5 lbs and the following number is length of burn in seconds and the 3rd number is the delay.
By the way can you give me the link to other forum where you found this info

#### Lawndart

##### Well-Known Member
Thanks for finding the above info, so I am assuming I have E motors. So does the 2.5 designate average thrust of 2.5 lbs and the following number is length of burn in seconds and the 3rd number is the delay.
By the way can you give me the link to other forum where you found this info
Also do a search on this forum. Lots of info from the past.

#### Jerry Thompson

##### Member
I suppose this is futile but does anyone have a thrust curve for any of the ProDyne engines?

#### Jerry Thompson

##### Member
Well I went digging thru some of my old rocketry documents and old catalogs from the 1960's and I found an old Prodyne catalog. Unfortunately it has some water damage but I did manage to fin some information on the ProDyne Cyclone and Hurricane thrust curves so thought I would share it for anyone else who is looking for it. See the enclosed file.

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#### shockie

##### High Plains Drifter
Here's some of my Pyrodyne documentation. More later as soon as I find it.

Here's a link to what I posted over on Ye Old Rocket Forum:

I also have an old magazine that has the thrust curves in it and as soon as I find and scan it I will post it

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#### aerostadt

##### Lifetime Supporter
TRF Lifetime Supporter
John passed away several years ago....
Yes, John rahkonen passed away a few years ago. He lived in one of the northern Utah suburbs not far from here. He still had lots of chemicals in private storage and his wife was very concerned. The local fire departments took the materials away and disposed of them. His motors were ahead of his time.

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#### Jerry Thompson

##### Member
Here's some of my Pyrodyne documentation. More later as soon as I find it.

Here's a link to what I posted over on Ye Old Rocket Forum:

I also have an old magazine that has the thrust curves in it and as soon as I find and scan it I will post it
Thanks for the documentation. It is better condition than my water damaged catalog. I did a static test of one of my cyclone motors and it worked fine. I put another into a custom rocket and it also worked fine. Because of its non standard size I had to make my own motor mount tube. I have since made several more somewhat heavy and draggy rockets to use with these motors because I don't want to lose them. A lot of my prodyne motors have quite a long delay in them, so unless I build 2 stage rockets I may have to archive them.

#### don carter

##### Sponsor
TRF Sponsor
John Rahkonen was a cool dude. He spent a week at my house many years ago. Tried to get me to buy drums of Pban. He would get up early in the morning, before sunrise, and run for 5 miles. I loved John. Wonderful man. Knew a lot about propellant, motors, etc. At the time (this was back in the 80s) I was looking at buying some chemicals. John had a bunch but I didn't want to buy ALL he had at the time. I just wanted to buy a portion of what he had. He also had drums of AP and lots of other chemicals as I recall. John told me he had been exposed to some pretty serious chemicals when he worked for Thiokol many years ago. I think it was from some of the chemicals that go into airbags. It had affected him pretty bad.

We corresponded for years after he went home. He loved my wife's southern cooking. He was of Finnish lineage. I think he was first generation if I'm not mistaken. He had so many stories to tell about Thiokol, propellant, and solid motors. He was fascinating. I would sit and listen to him for hours.

#### shockie

##### High Plains Drifter
Thanks for finding the above info, so I am assuming I have E motors. So does the 2.5 designate average thrust of 2.5 lbs and the following number is length of burn in seconds and the 3rd number is the delay.
By the way can you give me the link to other forum where you found this info