Centuri / Enerjet Parts - 3D Printing

[Tau Zero]

Over on Facebook, Jack Hydrazine shared a link to the group: Centuri Model Rockets.

"I have just published a 3D version of the Enerjet 1340 fin can that's pretty much an exact copy of the real thing which you can download from Thingiverse for free and print. Several Centuri kits used this fin can."

https://www.thingiverse.com/thing:3641770?fbclid=IwAR238khRfHKOglmOAiCVA7tO4siD9esijQaTpzRRskT5ps117KR2lpugxR8

"This is a replacement fin can for the following model rockets:

Enerjet 1340
Enerjet 1340/20
Centuri Phoenix Bird
Centuri Argus
Centuri MARS Project
Estes Longshot
Estes Maniac
Estes Challenger II
Estes Eliminator
Estes Eliminator XL

The dimensions were taken right from fin can and put into the CAD program I used to design it. The tubing designed to use it is Centuri ST-13 and the Estes BT-56. You can always scale it up or down to fit.

Will it reach and pass through transonic speeds and even into supersonic speeds remains to be seen. The massed produced one that came with various kits was not able to do so."


Posted per LTVscout's request. :D

[Tau Zero]

Centuri 5 Series Plastic Nose Cones

https://www.thingiverse.com/thing:559583


Centuri 7 Series Plastic Nose Cones

https://www.thingiverse.com/thing:560706


Centuri PNC 89

https://www.thingiverse.com/thing:576222


Doug's Fun Nozzle Pack #1

https://www.thingiverse.com/thing:559511

.

[Ltvscout]

Thanks, Jay!

[ghrocketman]

Very cool !
+1 to the Thanks !

[teflonrocketry1]

Over on Facebook, Jack Hydrazine shared a link to the group: Centuri Model Rockets.

"I have just published a 3D version of the Enerjet 1340 fin can that's pretty much an exact copy of the real thing which you can download from Thingiverse for free and print. Several Centuri kits used this fin can."

https://www.thingiverse.com/thing:3641770?fbclid=IwAR238khRfHKOglmOAiCVA7tO4siD9esijQaTpzRRskT5ps117KR2lpugxR8

"This is a replacement fin can for the following model rockets:

Enerjet 1340
Enerjet 1340/20
Centuri Phoenix Bird
Centuri Argus
Centuri MARS Project
Estes Longshot
Estes Maniac
Estes Challenger II
Estes Eliminator
Estes Eliminator XL

The dimensions were taken right from fin can and put into the CAD program I used to design it. The tubing designed to use it is Centuri ST-13 and the Estes BT-56. You can always scale it up or down to fit.

Will it reach and pass through transonic speeds and even into supersonic speeds remains to be seen. The massed produced one that came with various kits was not able to do so."


Posted per LTVscout's request. :D

Jay,

Many Thanks! I will try to print up a few to go with the nosecones and transitions I already made http://www.oldrocketforum.com/showthread.php?t=17892.

[Rocketflyer]

It may not be in keeping with things from the past, but I think that fin can would be better off with out the open area used a launch lug. It would work for two stagers, but for a single stage, make it smooth all the way around.

[teflonrocketry1]

My first attempt to print the fin-can for the 1320/1340 didn't go very well. I tried using red ABS filament with some printer settings that gave a low amount of warp in previous 3D prints I made, but the plastic won out and warped causing the fins to split see attached photo. Well at least I got a full print and can see the issues that need some attention for a good 3D print. I will probably try using PLA filament for the next attempt which is much less prone to warping but lower in strength and not as heat tolerant as ABS. I thought the ABS would make for a better fin-can because of its better resistance to heat. If I ever make an enclosure for my 3D printer perhaps I will be able to get an acceptable print in ABS plastic.

[MarkB.]

Bruce,

It looks like you sealed the area under the integral launch lug rather than leave it open as in the original, is that right? And the color is very similar to the Argus I had in the 70's.

Looking forward to you working out the bugs.

What, more or less, do you anticipate the cost for the fin can would be?

[teflonrocketry1]

Mark,

The area under the launch lug on the fin-can is sealed by the brim that the 3D printer software uses to adhere the part to the printer bed. It is only 0.36mm thick in this case and is easily removed. The color is a red ABS filament made by Vilarox that I have been using for duplicating the Centuri nosecones, it close to the original Centuri red orange color but not quite.

If I ever get a good print of this fin-can I will ask around $15.00 for the printed part (depends on the plastic). I have been asking $8.00 for shipping so the whole set; nosecone, coupler and fin-can will be $29.00 or a total of $37.00 with shipping. I just paid $32.00 for an Estes Eliminator Kit (#1950) that contains the nosecone and fin-can so I am not sure if I want to sell the fin-can for less to compete with that price.

I am currently working on getting a good print with a red PLA filament for the fin can. So far I am having issues switching my printer from ABS plastic back to PLA plastic.

[Jerry Irvine]

And the color is very similar to the Argus I had in the 70's.If that is the case then it is the likely source for the original 1340 fin units.

[Jack Hydrazine]

It may not be in keeping with things from the past, but I think that fin can would be better off with out the open area used a launch lug. It would work for two stagers, but for a single stage, make it smooth all the way around.

I created and posted a version at the same link of the fin can without the launch lug.

[Jack Hydrazine]

Mark,

The area under the launch lug on the fin-can is sealed by the brim that the 3D printer software uses to adhere the part to the printer bed. It is only 0.36mm thick in this case and is easily removed. The color is a red ABS filament made by Vilarox that I have been using for duplicating the Centuri nosecones, it close to the original Centuri red orange color but not quite.

If I ever get a good print of this fin-can I will ask around $15.00 for the printed part (depends on the plastic). I have been asking $8.00 for shipping so the whole set; nosecone, coupler and fin-can will be $29.00 or a total of $37.00 with shipping. I just paid $32.00 for an Estes Eliminator Kit (#1950) that contains the nosecone and fin-can so I am not sure if I want to sell the fin-can for less to compete with that price.

I am currently working on getting a good print with a red PLA filament for the fin can. So far I am having issues switching my printer from ABS plastic back to PLA plastic.

Glad to see someone is able to profit off my hard work! LOL!

[teflonrocketry1]

The 1320/1340 fin can printed up nicely in with red PLA filament, see picture attached. However this part is not flight worthy as the fins are much too thin and brittle, I doubt they would hold up in a flight or even a landing. I will attempt to rework the 3D file with the software (Blender) that I am learning to use. I plan to put in some reinforcing fillets and make the fins thicker, currently they are 1/16" thick and I think 3/32" thick will be better. The PLA fin can weighs in at 30 grams and the ABS one that has split fins due to warping weighs 31.5 grams.

Was the band on the transition for the 1320 really 0.25" thick? The one at 9:42 in this YouTube video https://www.youtube.com/watch?v=U7sy_fLYSPg looks like it is much thinner.

[Jerry Irvine]

Was the band on the transition for the 1320 really 0.25" thick? The one at 9:42 in this YouTube video https://www.youtube.com/watch?v=U7sy_fLYSPg looks like it is much thinner.
In light of that Youtube video I am going to have to concur with you as the rocket is clearly an Enerhet 1340 despite the nose cone not being shown. The molded payload coupler has a very thin ring. My past posts and memory are thus in error. I only saw that video for the first time this month.

Jerry

[teflonrocketry1]

I found this plan for the 1340 that indicates the band was 0.1" wide on the coupler http://plans.rocketshoppe.com/enerjet/enj1340/enj1340.pdf

It would be nice if someone with an original 1340 model would confirm this!

[Jerry Irvine]

I found this plan for the 1340 that indicates the band was 0.1" wide on the coupler http://plans.rocketshoppe.com/enerjet/enj1340/enj1340.pdf

It would be nice if someone with an original 1340 model would confirm this!
I do recall that brochure. I do recall my 1340. They did match. That is accurate.

[teflonrocketry1]

Jerry,

Thanks once again for your expert information! I appreciate having you on this forum to answer questions such as these, as I recognize you were one of the pioneers of high power rocketry.

Jack,

I mean no disrespect for 3D printing and offering the parts you provided the files for on thingiverse. I am not trying to start or run a business, I just want to recover my expenses for the 3D printing of these items. I see this as a way to make these rare parts available to those who have graciously helped me on this forum (like you and Jerry). Please accept my humble apologies if I have offended you.

[Jack Hydrazine]

Jack,

I mean no disrespect for 3D printing and offering the parts you provided the files for on thingiverse. I am not trying to start or run a business, I just want to recover my expenses for the 3D printing of these items. I see this as a way to make these rare parts available to those who have graciously helped me on this forum (like you and Jerry). Please accept my humble apologies if I have offended you.

I don't mind at all especially considering that Estes has stopped producing and selling the BT-56 tubing and the fin cans. We really needed a 3d model of the fin can to be designed.

The only problem I have with it is that the fin can really needs to be flight tested first just to ensure that it works before you sell them. I have printed one and the fins seem to be as strong or stronger than the mass-produced version, but testing first is the best way to go.

[teflonrocketry1]

I know from experience with other 3D printed fin-cans that 1/16" thick PLA fins won't hold up very well for flights or landings or even sitting in a hot car. I might try using PETG or a similar polymer as mentioned in https://forums.rocketshoppe.com/showpost.php?p=229416&postcount=6 . I am currently working on building an enclosure for my printers to get better ABS prints that don't split or warp. The 1/16" thick 3D prints of fins I made from ABS are much stronger than the same part made from PLA.

[Jack Hydrazine]

I recently learned about low-warp ABS being for sale on the retail market. I haven't tried it, but if you really want to print with ABS this might be the way to go.

https://www.pushplastic.com/products/low-warp-abs-filament

https://www.amazon.com/HQA-ABS-LW-3D-Printer-Filament/dp/B07BWGMPDL

[ghrocketman]

That Amazon price is about 40% lower for 33% more product.

[Jack Hydrazine]

I know from experience with other 3D printed fin-cans that 1/16" thick PLA fins won't hold up very well for flights or landings or even sitting in a hot car.

PLA has a glass transition temperature of 60–65 °C (140 F - 149 F) and a melting temperature of 173–178 °C (343.4 F - 352.4 F).

PETG has a glass transitition temp of 80 C (176 F) and a melting temp of 210 - 250 C (410 - 482 F).

You can increase the strength of PLA. Steve Jurvetson made a fin can with PLA for his daughter's rocket and flew it past Mach several times. The key was coating it with some epoxy.
https://www.thingiverse.com/thing:630069

Video about it starts at the 11:00 mark.
https://www.youtube.com/watch?v=IBMMPBpZeHo

[teflonrocketry1]

I recently learned about low-warp ABS being for sale on the retail market. I haven't tried it, but if you really want to print with ABS this might be the way to go.

https://www.pushplastic.com/products/low-warp-abs-filament

https://www.amazon.com/HQA-ABS-LW-3D-Printer-Filament/dp/B07BWGMPDL

Jack,

I am aware of the low warp ABS, I haven't purchased any since it is over my $17/kg price point for filament.

I purchased some 3/4" thick foam board for $8.38 from Home Depot:

https://www.homedepot.com/p/3-4-in-x-1-25-ft-x-4-ft-R-2-65-Polystyrene-Panel-Insulation-Sheathing-6-Pack-150705/202090272

and built an insulated enclosure (R2.89) for my 3D printer today, see attached picture. I am attempting to print a 1340/20 fin-can in ABS filament again, at high resolution it takes about 6 hours, if this works, problem solved.

[teflonrocketry1]

It worked!, see first picture! I opened the enclosure 6 hours later and found an almost perfect ABS print of the 1340/20 fin-can with no warping or splitting. The second picture shows the latest print detached from the supporting material next to the ABS print from before that has warped and split fins. This ABS print is strong and flexible and very flight worthy.

[Jerry Irvine]

It worked!, see first picture! I opened the enclosure 6 hours later and found an almost perfect ABS print of the 1340/20 fin-can with no warping or splitting. The second picture shows the latest print detached from the supporting material next to the ABS print from before that has warped and split fins. This ABS print is strong and flexible and very flight worthy.I would be proud to try a set and fly them with photos.

[ghrocketman]

VERY NICE, Bruce !
Put me in line for wanting one of your orange fin cans !
Really !

[ratchetman]

I agree, very well done Bruce, bravo!
I also would be pleased to be in line to obtain one of those fin cans. Red would be great.

[astronwolf]

Great job, Bruce. :cool:

[Quasar]

I will attempt to rework the 3D file with the software (Blender) that I am learning to use.

Blender is a really powerful CG program that I've been playing around with, too. Below is a 3D model of a Cherokee-D that I made with Blender.

https://i.postimg.cc/SxRCVHh9/Cherokee-D-final.png

[Jack Hydrazine]

It worked!, see first picture! I opened the enclosure 6 hours later and found an almost perfect ABS print of the 1340/20 fin-can with no warping or splitting. The second picture shows the latest print detached from the supporting material next to the ABS print from before that has warped and split fins. This ABS print is strong and flexible and very flight worthy.

How hot was the ambient temperature of the print chamber during printing?

[teflonrocketry1]

Jack,

I don't know the temperature inside the chamber during the 3D print, I think it was more than 60C and less than 100C, the setting of the hot bed temperature. I will try to measure the temperature with a thermocouple placed in the chamber on the next fin-can I print.

If anyone is interested I have a few of the 1340/20 fin-cans printed in red ABS for 1.34" outside diameter tubing ; PM me if you want one. I am asking $15.00 each plus $8.00 shipping and handling. I also have a few nosecones and transition sections printed for the LT-125 tubing.

[teflonrocketry1]

Enerjet 1340 mock-up day, see pictures attached. Not sure what colors I should go with as there is no good source about the colors of the original.

[Jack Hydrazine]

Those look really good.

[Jerry Irvine]

Enerjet 1340 mock-up day, see pictures attached. Not sure what colors I should go with as there is no good source about the colors of the original.
Red-Red. This is the first time I have seen a 1340 in years. White tube and Enerjet decal. Simple. Now all you need is a G76!

Take a picture of that one all by itself with the brochure and sell kits! Or send me 24 sets and I will make a short run of kits.

[Jack Hydrazine]

Here's the promo flyer. I colorized it and found that the colors are white on the nose cone, part of the payload bay, and the fins. The air frame is a gray color and the other half of the payload bay is aluminum.

I don't know from where the red, white, and blue color scheme originates. It might originate from the original kit.
https://www.worthpoint.com/worthopedia/extremely-centuri-enejet-1340-251820623

You can see in the kit that the nose cone is red, the fin can is blue, the payload bay tubing coupler is red. I did find a pica online of what it might look like.

How many paint schemes did the 1340 have?

[Earl]

Here's the promo flyer. I colorized it and found that the colors are white on the nose cone, part of the payload bay, and the fins. The air frame is a gray color and the other half of the payload bay is aluminum.

I don't know from where the red, white, and blue color scheme originates. It might originate from the original kit.
https://www.worthpoint.com/worthopedia/extremely-centuri-enejet-1340-251820623

You can see in the kit that the nose cone is red, the fin can is blue, the payload bay tubing coupler is red. I did find a pica online of what it might look like.

How many paint schemes did the 1340 have?

The 1340 thick walled nosecone and payload tube connector -- which were specific to that vehicle -- were only red as far as I have ever seen.

The fin can -- which was eventually shared in other kits -- could have come in other colors later on, but was also probably red in most instances.

The cover photo on the 1340 brochure is actually an aberation, since that vehicle is basically the 'consumer' Nike Ram kit with Nike Ram paint pattern, with a white (probably painted) fin can. That photo is NOT of a typical 1340 vehicle.

Earl

[Jerry Irvine]

The cover photo on the 1340 brochure is actually an aberation, since that vehicle is basically the 'consumer' Nike Ram kit with Nike Ram paint pattern, with a white (probably painted) fin can. That photo is NOT of a typical 1340 vehicle.
Earl Exactly. The real main tube was ST-125 with a BT-11 Enerjet (now Estes) version slid inside. Usually with some tape. No thrust ring per normal Enerjet style to accomodate all 3 motor lengths (E24/F52-F67/G76) The vaporware H111 would have been longer.

Jerry

[Jack Hydrazine]

The ST-125 was the airframe tubing that had an O.D. of 1.34" and an I.D. of 1.25" with a wall thickness of 0.045"?

The BT-11 was the 29mm motor mount tube? The O.D. was large enough to slip into the 1.25" airframe I.D.?

[Jerry Irvine]

The ST-125 was the airframe tubing that had an O.D. of 1.34" and an I.D. of 1.25" with a wall thickness of 0.045"?

The BT-11 was the 29mm motor mount tube? The O.D. was large enough to slip into the 1.25" airframe I.D.?Yes.

USR/Ace BT-11 is 1.14 x 1.22. Estes/Enerjet BT-11 (whatever they really call it) is 1.14 with a thinner wall around 1.20 OD. I have some around here somewhere.

Jerry

[teflonrocketry1]

Finished my 1340 clone with a 29mm motor mount. It has 3D printed nosecone, transition and fin-can, and homemade decals printed on a an inkjet printer, see picture.

Does anyone know if there were there decals on both sides of the rocket?

[ghrocketman]

To the best of my knowledge, the large Enerjet decal was only on one side.

[Jack Hydrazine]

Looks great. Time for a flight!

[K'Tesh]

Finished my 1340 clone with a 29mm motor mount. It has 3D printed nosecone, transition and fin-can, and homemade decals printed on a an inkjet printer, see picture.

Does anyone know if there were there decals on both sides of the rocket?
When my next shipment from eRockets arrives, I will get the original Enerjet decals I scored from eBay. I can't wait to scan them with a ruler to ensure the scaling is correct.

[teflonrocketry1]

I just cleaned up these (http://plans.rocketshoppe.com/decals/Enerjet_Decals.tif) and printed them on clear water slide inkjet decal paper then used one nice coat of KRYLON Crystal Clear # 1303.

[Jerry Irvine]

I just cleaned up these (http://plans.rocketshoppe.com/decals/Enerjet_Decals.tif) and printed them on clear water slide inkjet decal paper then used one nice coat of KRYLON Crystal Clear # 1303.
Post the file?

[teflonrocketry1]

The attached .jpg file is the Enerjet decal I cleaned up using Microsoft paint. I used a print from this file on my 1340 clone. Note this is a low resolution file created from the original .tif file which was made at 600dpi , some detail has been lost and the edges appear fuzzy.

[Jack Hydrazine]

Is the STL file for the 1340 nose cone posted on Thingiverse? If not, could you post it? Thanks!

It looks to me like a 5:1 rounded ogive.

[teflonrocketry1]

See attached .obj files for 1340 nose cone and coupler. I created these files with RockSim and 3D printed them using ABS and both parts both fit the LT-125 tubing that I have. If you need these files for Centuri ST-13 tubing or BT-55 just let me know.

[Jack Hydrazine]

Thanks! I appreciate that greatly!

[teflonrocketry1]

Picture of my 1340/20 clones; homemade decals and 3D printed ABS fin cans, transitions and nosecones. Might fly these at NARAM this week if I ever get there.

[ghrocketman]

Is the photo distorted or is the large payload at right slightly flattened near the top ?

[teflonrocketry1]

The photo is distorted, that's what happens when you take pictures with your cell phone late at night.

[ghrocketman]

I figured it most likely was distortion.
Nobody on this forum would build a BENT Enerjet anything.

[Jack Hydrazine]

They look great and ready for flight. Be sure to get so great liftoff shots of them.

[snaquin]

Picture of my 1340/20 clones; homemade decals and 3D printed ABS fin cans, transitions and nosecones. Might fly these at NARAM this week if I ever get there.
Beautiful Bruce! Did you fly these at NARAM?

[teflonrocketry1]

Beautiful Bruce! Did you fly these at NARAM?

I flew and damaged both of them at NARAM see pictures. The 1320 (payload version) was flown on a D12-3; this was its second flight as the first attempt hung up on the launch pad either due to a bad alignment of the (authentic) wire loop launch lugs or the lower wire lug catching the spring on the clothespin underneath it. The 1320 was flown on a C11-3. Both were good straight flights, with a 18 inch diameter plastic parachute (with a 2 inch spill hole) for recovery. I used the Estes Plastic 24mm to 29mm Engine Adapter (009753) for both flights. The 1320 got some "road rash" from being dragged over the asphalt pavement near the launch site and the 1340 suffered a cracked fin when it landed on the same surface. The cracked fin was easily repaired with CA glue, but the road rash on the 1320 will have to wait for a future repaint or rebuild.

[Jack Hydrazine]

The Enejet 1340 fin cans I have designed so far.

Enerjet 1340 Fin Can #1 (Original, FOUR FIN)
https://www.thingiverse.com/thing:3641770

Enerjet 1340 Fin Can #2 (supersonic, FOUR FIN)
https://www.thingiverse.com/thing:3829871

Enerjet 1340 Fin Can #3 (supersonic, THREE FIN)
https://www.thingiverse.com/thing:3831483

Enerjet 1340 Fin Can #4 (original, THREE FIN)
https://www.thingiverse.com/thing:3834846

Enerjet 1340 Fin Can #5 (original, FIVE FIN)
https://www.thingiverse.com/thing:3837575

Enerjet 1340 Fin Can #6 (original, SIX FIN)
https://www.thingiverse.com/thing:3837581