Fly-away rail guides: 54mm 3D-printed available now

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If I did my math right, at 300g you only need about 4 inches of guidance until aerodynamics starts working.
If these things work, they would be worth $10 a launch just to not have to mess with setting up the tower and its build cost.
 
What is the volume of those parts?

I can see this being economical for small (38 and under) rockets, but the print time looks like it would be pretty significant for bigger rockets.
 
I concur with wearing out rail buttons with high force flights. I use delrin buttons on my 54 SpaceCowboy when not using a tower. After every flight [5grain -6xl ] flights I must loosen the button..... turn a few degrees to a "fresh" spot, due to the flat edges I now have. LOL

BUT.....yesterday at our launch there was an USLI team there with 3d printed fin can [replaceable fins to boot, slide in tracks] and a midsection airframe with 5 flip out air brake flaps. 3in rocket [proof of concept] before the full size version. Altitude limit of 5200 ft. Anyhow.......

What caught my eye was the fin can with replaceable fins and what I saw after recovery. It came down in some trees and one of the fins hit a good size limb. It was forced up THROUGH the carbon airframe cutting it about 2-3inches zipper.....with vitally NO damage to the fin, [just a nick]

SO I cornered the mechanical engineering student behind the design and printing. It's a high temp [you set the heat on needle to 300 something degrees to print, this fins are stiff and sturdy like G-10 plate. Surface is slippery smooth, natural color is like champagne. Name of material was just a bunch of numbers & letters. I'll make contact with the captain and see what that stuff is, it definitely is not your mom's standard 3d material.

And it ain't cheap 90.00 per cubic in.... of material he told me. BUT something like this may allow making a second type of POP offs for the "high stress" fliers along with the standard version for the majority of more Tame flights.
 
blackjack2564 said:
I concur with wearing out rail buttons with high force flights. I use delrin buttons on my 54 SpaceCowboy when not using a tower. After every flight [5grain -6xl ] flights I must loosen the button..... turn a few degrees to a "fresh" spot, due to the flat edges I now have. LOL

BUT.....yesterday at our launch there was an USLI team there with 3d printed fin can [replaceable fins to boot, slide in tracks] and a midsection airframe with 5 flip out air brake flaps. 3in rocket [proof of concept] before the full size version. Altitude limit of 5200 ft. Anyhow.......

What caught my eye was the fin can with replaceable fins and what I saw after recovery. It came down in some trees and one of the fins hit a good size limb. It was forced up THROUGH the carbon airframe cutting it about 2-3inches zipper.....with vitally NO damage to the fin, [just a nick]

SO I cornered the mechanical engineering student behind the design and printing. It's a high temp [you set the heat on needle to 300 something degrees to print, this fins are stiff and sturdy like G-10 plate. Surface is slippery smooth, natural color is like champagne. Name of material was just a bunch of numbers & letters. I'll make contact with the captain and see what that stuff is, it definitely is not your mom's standard 3d material.

And it ain't cheap 90.00 per cubic in.... of material he told me. BUT something like this may allow making a second type of POP offs for the "high stress" fliers along with the standard version for the majority of more Tame flights.
Click to expand...

Wow you bet. If a printing service could be found that can do it I could have them print the things from my designs using the new material on a special-request basis.
 
Undue stress accrued during launches?
I have it every time I launch a rocket and better launch lugs aren’t going to help.

Usually it requires Valium.

That being said; I’d really like to get my hands on a set for 38mm tubes.
 
I think to sell these things I have to hit $15-$20 or so for the light duty parts and the $20-$25 range for the newer design, which has as much plastic as landru's 4" sled ($25) and is a more complicated print. Plus a couple of bucks shipping. Quantities would be pretty low until I can use proceeds to scale up the operation. I don't know if those numbers are a deal-breaker.
 
blackjack2564 said:
I concur with wearing out rail buttons with high force flights. I use delrin buttons on my 54 SpaceCowboy when not using a tower. After every flight [5grain -6xl ] flights I must loosen the button..... turn a few degrees to a "fresh" spot, due to the flat edges I now have. LOL

BUT.....yesterday at our launch there was an USLI team there with 3d printed fin can [replaceable fins to boot, slide in tracks] and a midsection airframe with 5 flip out air brake flaps. 3in rocket [proof of concept] before the full size version. Altitude limit of 5200 ft. Anyhow.......

What caught my eye was the fin can with replaceable fins and what I saw after recovery. It came down in some trees and one of the fins hit a good size limb. It was forced up THROUGH the carbon airframe cutting it about 2-3inches zipper.....with vitally NO damage to the fin, [just a nick]

SO I cornered the mechanical engineering student behind the design and printing. It's a high temp [you set the heat on needle to 300 something degrees to print, this fins are stiff and sturdy like G-10 plate. Surface is slippery smooth, natural color is like champagne. Name of material was just a bunch of numbers & letters. I'll make contact with the captain and see what that stuff is, it definitely is not your mom's standard 3d material.

And it ain't cheap 90.00 per cubic in.... of material he told me. BUT something like this may allow making a second type of POP offs for the "high stress" fliers along with the standard version for the majority of more Tame flights.
Click to expand...

I'm sure it's Ultem 9085
https://www.stratasys.com/materials/fdm/ultem-9085

Unfortunately it's crazy expensive just for the material, and the printers that can use it start around 150K. For any service bureau that can make one, I'm sure it will be upwards of $300 to make a guide like these unless you know somebody.
 
Yep that looks like the color. He told me they tried to outsource the fin can, but the best price was 8700.00 so they made it on university equipment in Charlotte for 800.00 in material.

Must be nice having access to all that equipment. Kinda put theses guides into the "stratosphere" price range.....oh well ...
 
If you can find a way to print them in a dual material setup or make the button part of the unit bolt on or otherwise replaceable it may make it reasonable.
 
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You could also replace the button section with some sort of roller or bearing on both sides so they roll instead of slide on the rail. It would probably make them a bit more expensive but they would most likely be much more durable.
 
First off I love your ingenuity, Mr. Cook! This is an excellent use of 3Dp and I would totally buy a couple of these from you. I would also be interested in the .stl file(s) if you're still planning post them but, if not, I totally understand. :)

I'm curious on the comments above about needing to replace Delrin rail guides after every high-velocity flight. I used to crank my rail guides down so they were rigidly held in place. This prevented rotation about the mounting screw(s) and I definitely saw the post-flight wear you mention. More recently I only crank the screws down until the screw head just touched the guide therefore leaving a bit of rotational freedom and now there are never signs of wear on the guides. Has anyone else tested this difference?

Thanks,

=G=
 
Here are two buttons, both Delrin. Black one is still on rocket, so I had to X-cut paper to fit over it & blacken background so you could see the white one.

White was set loose to spin. Lasted one flight, other one of pair was so destroyed, only the screw and some remnants of button were left.


Black one has 3 flights on it, now falls out of slot, need to turn to fresh section. [ click 3 times to get full size]

DSCN3775.jpg DSCN3780.jpg

These 2 rockets fly a lot on high velocity motors, white buttons were on an N-5800.
Black on rocket that flies mostly CTI White thunder and AT Blue thunder.

So there you go....useless after one flight & three. I think all this depends on your combination of rocket/motor & how high velocity is .

For me buttons are so cheap I just plan on replacing them.


Back to the OP's product, the outcome will be very interesting. I think for long-burns and most motors/ user's [ probably 98% ish], I think they will be fine as long as there are no issues with fins hitting them/damage. That will all come out in testing and any adjustments needed.

Extreme flights will probably still be done with towers. [funny ...you can tell who's done this stuff and who hasn't, by many of the comments]

It looks to be a great advance & problem solver for many & that's a good thing. I know would I love to get my hands on one, & will beat the hell out of it ! LOL:grin:
 
for low production injection molding I have had good luck with these guys but I'm guessing you don't have the quantity to buy the molds over printing them.

https://www.protolabs.com

You might try to find a tech college with a small injection press
 
All right I think that with a new 3D printer I can bring the price down a bit. There is still some testing to be done with higher-thrust motors, and a printer acquisition to be made, but if that all goes well I will be looking to have 38mm models for thin-wall, thick-wall (FG, Blue Tube, etc), and flying case (true 38mm) rockets.

And then if that is successful I'll look into 54mm and 29mm sizes.

More to come.
 
wfcook said:
All right I think that with a new 3D printer I can bring the price down a bit. There is still some testing to be done with higher-thrust motors, and a printer acquisition to be made, but if that all goes well I will be looking to have 38mm models for thin-wall, thick-wall (FG, Blue Tube, etc), and flying case (true 38mm) rockets.

And then if that is successful I'll look into 54mm and 29mm sizes.

More to come.
Click to expand...

Awaiting possitive word of testing and manufacturing of these as I definately will be purchasing 38mm and 54mm when/if available.

Greg
 
Quick comment/question: What prevents the fincan from slamming into the fly-away rail guide frame with high velocity projects? With the rubber band tension on the rail quide, I'd be a bit concerned about drag with the rocket body sliding "up" on the rail guide and slamming into the fincan before the rocket assembly is off the rail. I suppose one could come up with a "stop" on the airframe to keep that from happening. Kurt
 
ksaves2 said:
Quick comment/question: What prevents the fincan from slamming into the fly-away rail guide frame with high velocity projects? With the rubber band tension on the rail quide, I'd be a bit concerned about drag with the rocket body sliding "up" on the rail guide and slamming into the fincan before the rocket assembly is off the rail. I suppose one could come up with a "stop" on the airframe to keep that from happening. Kurt
Click to expand...

The plan is for the guide to begin the flight backed up to the fins. When it springs apart it is moving at the same velocity as the rocket and any fin strikes should be minimal.

For flights where you want multiple guides, I think some further testing will be required and I have plans for that. For now my thinking is that the single guide should be adequate for most 38mm rockets with commercially available motors. They are pretty stout.
 
This is very cool. If you can, get a good high speed camera zoomed in on the top of the rail, perpendicular to the active rail slot. That way the dynamics of the release can be seen.

As for slippage between the body and the guide, you only need more friction in the sleeve than you have at the guides (plus a factor of safety that should be greater than the μs/μd ratio) and it shouldn't budge unless the guide hits a snag in the rail. In the worst case scenario you could print the guides for a slightly larger body dimension and coat the inside with a rubberized material to gain a higher μ.

Can't wait to see it in action!
 
wfcook said:
The plan is for the guide to begin the flight backed up to the fins. When it springs apart it is moving at the same velocity as the rocket and any fin strikes should be minimal.

For flights where you want multiple guides, I think some further testing will be required and I have plans for that. For now my thinking is that the single guide should be adequate for most 38mm rockets with commercially available motors. They are pretty stout.
Click to expand...

Ok, Fair enough. Would likely want G10/12 fins or glassed plywood fine material. Also a clean rail with perhaps a silicone lubricant (if the rail guides wouldn't be dissolved by it) to make the guide/rail interface as "slick" as possible would be one way around
friction drag. Kurt
 
Received the new rail guides today and they fit like a custom glove. I've included 2 photos of each one of the guides. If you look closely, with the added stand offs there is nice clearance for the cradle to the rail, there is absolutely no friction now, slides up and down the rail very smoothly. Also, I've noticed no slippage of the rail guides around the airframe. This test, I am going to video so everyone can get a view of the rail guides in action. Will give them a test this Sunday so stay tuned.

View attachment 251834 View attachment 251835
 
Thanks again to Rockdoc for testing these. I'm going to test these as completely as possible and if everything turns out as I expect, I want to go into production ASAP. I hope to cover a range of 38mm tubes to start and theen branch out into 54mm and 29mm if things go well.

But first things first...I don't want to be selling a product that doesn't work as advertised.
 
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wfcook said:
Thanks again to Rockdoc for testing these. I'm going to test these as completely as possible and if everything turns out as I expect, I want to go into production ASAP. I hope to cover a range of 38mm tubes to start and theen branch out into 54mm and 29mm if things go well.

But first things first...I don't want to be selling a product that doesn't work as advertised.
Click to expand...

Bill, if this thing works half as well as your triple canted motor Red Barron I may have to join the NAR! :rofl: Seriously man, nice work!
 
I really would like to see these in action. Sorry I had to cancel the launch for the 18th due to weather. I hope the conditions are better next weekend.
 

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