3.3" Dynacom Python

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mpitfield

mpitfield

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Last year I picked up a OOP 3.3" Dynacom Python kit from a local club member who was looking to offload some kits due to him not being very active in the hobby. For those who don't know the kit or the manufacturer two things come to mind when you see the components, it was ahead of it's day and the quality of components and workmanship must have been second to none. Even today there are very few manufactures that build kits with this much attention to detail.

That being said, when I picked up the kit it was missing the fins. Apparently they are not lost but just misplaced. However here I am still with no fins and this is a project I would like to start assembling this summer. I was able to find a sim file which I have validated against the components, as well the kit did come with very detailed specifications which included mostly everything I needed to extrapolate the fin dimensions. That being said the fins look much bigger in the sim file than the online pictures, so I would like to validate them with anyone that knows the kit.

Aside from that I was contemplating building new fins from carbon plate simply because if the dimensions are accurate then these fins are relatively large and I may rip them off based on the motors I may fly. Thoughts, who knows this kit?

Below is a screenshot from OR and attached is the OR file View attachment Dynacom_Python_54.ork.

 
I also picked up a Python a few years ago and built it but have never flew it. What are your plans for recovery? Its not really set up for a standard DD. I could go with a JLCR.
 
crossfire said:
I also picked up a Python a few years ago and built it but have never flew it. What are your plans for recovery? Its not really set up for a standard DD. I could go with a JLCR.
Click to expand...

So far I haven't given the kit much thought because I have quite a few others on the build pile ahead of it. However what I am considering is the following:

- cut roughly 10" off the existing 30" MMT
- remove the integrated recovery attachment pin in the MMT
- add a y harness to what is currently the middle CR which will become the top CR
- make carbon plate fins, same dimensions
- fill the machined spots for the launch lugs and use rail buttons, or nothing and go with a 3" FARG

What I need to put some thought into is the following:

- possibly swap out the integrated tailcone retainer with something that will work with my Loki hardware
- how to make this a clean DD

Or just build it stock for nostalgic reasons.
 
Loki 54mm hardware works with Slimline threaded retainers (not sure about the other ones) and the fastback retainers from MAC performance. I've put this kind of retainer inside a boattail before, and you could do something similar.
 
AdAstraPerAspera said:
Loki 54mm hardware works with Slimline threaded retainers (not sure about the other ones) and the fastback retainers from MAC performance. I've put this kind of retainer inside a boattail before, and you could do something similar.
Click to expand...

The previous owner started to assemble this one. He got as far as gluing the retainer, boat-tail, and all three CRs to the MMT. It looks like he used decent epoxy, although one thing I am pretty sure I will do is cut roughly 10" off the MMT. If I do this then I will try to remove the CR on the scrap piece as a test and if it does comes off without killing it then I will look into swapping out the retainer for something compatible with Loki

crossfire said:
I also have a Dyna Com Black Widow with same motor retainer as the Python. AT and CTI fit perfect.
Click to expand...

While I would be happy launching on AT and CTI, also having Loki as an option would ideal.

Steve Shannon said:
I think I bought a Dynacom something or other from you several years ago didn’t I? It’s still in its box in the basement. I should build it.
Click to expand...

Please dig it out and let me know if it is the 3.3" Python

patelldp said:
https://www.rocketryforum.com/showt...bonus-Python-data-too!)&p=1574235#post1574235
Click to expand...

Hi Dan, That's where I found the sim file...thanks! However where I am questioning the accuracy is on the fins. The specs say the root chord is 14.25 but your sim file shows root chord as being 13.63". Also do you have any pictures of yours? All the pic inks to imgur seem to be dead from that thread.

Below is a pic of what I think may have been a brochure. It contains several of their rockets including the Python, which the previous owner gave to me with rocket.

 
Last edited:
I have a catalog from 1995 that reads fin root cord for Python is 13.63
 
mpitfield said:
Hi Dan, That's where I found the sim file...thanks! However where I am questioning the accuracy is on the fins. The specs say the root chord is 14.25 but your sim file shows root chord as being 13.63". Also do you have any pictures of yours? All the pic inks to imgur seem to be dead from that thread.
Click to expand...

That file was made by measuring an actual rocket. Killed the images in that thread because this place is annoying. Only posting now because you probably have one of the last kits out there...there's certainly less than 10 of these unbuilt out there, likely less than 5...

Enjoy!
 
recon60 said:
I have a catalog from 1995 that reads fin root cord for Python is 13.63
Click to expand...

Hi recon60, thanks for the info. Is there anyway you can scan, pdf and upload that document here?

patelldp said:
That file was made by measuring an actual rocket. Killed the images in that thread because this place is annoying. Only posting now because you probably have one of the last kits out there...there's certainly less than 10 of these unbuilt out there, likely less than 5...

Enjoy!
Click to expand...

Thanks Dan, and I BTW hear you.

Well so far that is two against one so it is leaning towards my documentation being incorrect or a different version. I will scan and convert the document to a pdf and upload it here for reference as I think it contains info 3 Dynacom rockets.
 
mpitfield said:
The previous owner started to assemble this one. He got as far as gluing the retainer, boat-tail, and all three CRs to the MMT. It looks like he used decent epoxy, although one thing I am pretty sure I will do is cut roughly 10" off the MMT. If I do this then I will try to remove the CR on the scrap piece as a test and if it does comes off without killing it then I will look into swapping out the retainer for something compatible with Loki



While I would be happy launching on AT and CTI, also having Loki as an option would ideal.



Please dig it out and let me know if it is the 3.3" Python



Hi Dan, That's where I found the sim file...thanks! However where I am questioning the accuracy is on the fins. The specs say the root chord is 14.25 but your sim file shows root chord as being 13.63". Also do you have any pictures of yours? All the pic inks to imgur seem to be dead from that thread.

Below is a pic of what I think may have been a brochure. It contains several of their rockets including the Python, which the previous owner gave to me with rocket.

Click to expand...

I think Eric made 2 styles of the Python. The picture I have here shows the fins slotted almost all the way down the tail cone. The Python I built has the fin slots starting just above the tail cone in the booster tube. Here are the specs. for the tail cone slotted style

airframe 3.30"
ogive N/C 16.50"
payload section 12"
fins 4
fin root chord 13.63"
distance to TC 7.38"
exposed area 40.53"
diamond airfoil 7.5"
L/D ration 23.18"
length 76.50"
NC caliber 5
weight W/O motor 7.80#
fin span 4.50"
fin tip chord 5.75"
fin thickness 0.125"
total equiv. area 64.76
leading edge sweep 61.00"
CP 57.59"
 
crossfire said:
I think Eric made 2 styles of the Python. The picture I have here shows the fins slotted almost all the way down the tail cone. The Python I built has the fin slots starting just above the tail cone in the booster tube. Here are the specs. for the tail cone slotted style

airframe 3.30"
ogive N/C 16.50"
payload section 12"
fins 4
fin root chord 13.63"
distance to TC 7.38"
exposed area 40.53"
diamond airfoil 7.5"
L/D ration 23.18"
length 76.50"
NC caliber 5
weight W/O motor 7.80#
fin span 4.50"
fin tip chord 5.75"
fin thickness 0.125"
total equiv. area 64.76
leading edge sweep 61.00"
CP 57.59"
Click to expand...

Hmm interesting...

Below is an easy to follow side by side comparison of the specs you took from your build to the specs listed in my brochure:

Item Description
Taken from your Python
My Specs
Airframe
3.3"
3.3"
Ogive NC
16.5"
16.5"
Payload Section
12"
12"
Fins
4
4
Fin Root Chord
13.63"
14.25"
Distance to TC (Tip Chord)
7.38"
8.25"
Exposed Fin Area
40.53"²
42.125"²
Diamond Airfoil
7.5°
7°
Length to Diameter Ratio
21.18
24.09
Overall Length
76.5"
79.5"
NC Caliber
5
5
Weight W/O Motor
7.8#
5.75#
Fin Span
4.5
5"
Fin Tip Chord
5.75
5"
Fin Thickness
.125"
.125
Leading Edge Sweep
61°
58.78°
CP
57.59"
45.9"
Total Fin Area
64.76"²
68.61"²

The first question I need to answer is are my specs representative of my actual components. Either Dynacom created more than one version and tweaked the specs, or my brochure is incorrect.

Thanks for your insight!
 
Michael
The specs. posted are not from my build but are from the 1995 Dynacom catalog. The catalog show kit with fins slotted into the tail cone.
 
crossfire said:
Michael
The specs. posted are not from my build but are from the 1995 Dynacom catalog. The catalog show kit with fins slotted into the tail cone.
Click to expand...

I checked my catalog and I did not see a date on it, just "CATALOG 003". I wonder if this predates your 95 catalog or follows it?



AdAstraPerAspera said:
Loki 54mm hardware works with Slimline threaded retainers (not sure about the other ones) and the fastback retainers from MAC performance. I've put this kind of retainer inside a boattail before, and you could do something similar.
Click to expand...

I was also able to get into my shop and actually do some work this evening. Even though I have other builds that I should be working on I was curious to see how easy or possible it would be to disassemble the components that were assembled with epoxy years ago. I am happy to say that with a few whacks of the hammer the epoxy cracked and I managed to get some scrapers in between and pried the epoxy off. I was able to remove the top and middle CR, as well as the pin that holds the recovery cable in place on the forward end of the MMT. That is when I discovered that there was a smaller diameter thin walled tube in the end of the MMT to reinforce where the pin slid through. At the end everything came out and cleaned up like new.

More importantly I was able to hold onto the retainer and rotate it on the MMT. Right now it's about a 1mm off and I am confident that with a bit more finessing it will come completely off. I then test fit the MAC fastback retainer on the forward end of the MMT and it looks like it will fit well. However in order for it to fit flush with the aft end of the boattail I will have to shave a bit off the boattail, but that should be doable. The last piece to tackle is separating the tailcone from the MMT. Although it would be convenient having those two components apart it might also prove to be more challenging than it's worth and I am not sure that it is necessary, so I may just let sleeping dogs lie.

The really good news is that Loki hardware will now be an option to fly and I may even be able to fit the Loki 54-4000 hardware in there...but then again the two motors that fit in that hardware might just leave those oversized fins on the pad.
 
mpitfield said:
I checked my catalog and I did not see a date on it, just "CATALOG 003". I wonder if this predates your 95 catalog or follows it?





I was also able to get into my shop and actually do some work this evening. Even though I have other builds that I should be working on I was curious to see how easy or possible it would be to disassemble the components that were assembled with epoxy years ago. I am happy to say that with a few whacks of the hammer the epoxy cracked and I managed to get some scrapers in between and pried the epoxy off. I was able to remove the top and middle CR, as well as the pin that holds the recovery cable in place on the forward end of the MMT. That is when I discovered that there was a smaller diameter thin walled tube in the end of the MMT to reinforce where the pin slid through. At the end everything came out and cleaned up like new.

More importantly I was able to hold onto the retainer and rotate it on the MMT. Right now it's about a 1mm off and I am confident that with a bit more finessing it will come completely off. I then test fit the MAC fastback retainer on the forward end of the MMT and it looks like it will fit well. However in order for it to fit flush with the aft end of the boattail I will have to shave a bit off the boattail, but that should be doable. The last piece to tackle is separating the tailcone from the MMT. Although it would be convenient having those two components apart it might also prove to be more challenging than it's worth and I am not sure that it is necessary, so I may just let sleeping dogs lie.

The really good news is that Loki hardware will now be an option to fly and I may even be able to fit the Loki 54-4000 hardware in there...but then again the two motors that fit in that hardware might just leave those oversized fins on the pad.
Click to expand...

All mine says is !995 Aerospecialties catalog. No catalog number.
 

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