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

UPDATE:

The 54mm guides have been a long time coming, but they are available now. I have also re-designed the 38mm guides based on what I've learned making the 54s, and I have moved to a new, stronger material (PETG) which is also better in the heat of mid-day sun, inside a car, etc. The new 38mm guides will be available mid-October 2015, depending on this hurricane we have bearing down on us.

The launch reports from BALLS24 have been great!

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AVAILABILITY: These are available from Animal Motor Works.

I've UPDATED the design a bit based on rockdoc's feedback, and I've posted a video. I think these are an improvement, although they take quite a bit more time to print. See post #60.

Some launcch video: in post #100

------------ ORIGINAL POST:

I'm starting this thread to solicit commentary from the group on some 3D-printed fly-away rail guides I've designed. I've mentioned them in other threads, and in the interest of not hijacking those any further I've decided to move the discussion here. This design is based on an R&D paper presented at NARAM-52 (2010) by Tim Van Milligan, so the basic concept is not mine, although the 3D-printed part was developed by me.

I want to thank atlcdp, who printed me a set of my original design, which unfortunately was not very good. The parts were fine, but my design was gawd-awful. I managed to get my hands on a 3D-printer for a little while, and so I've been able to iterate through several different concepts and improvements to get where I am now. There is about a pound and a half of dead PLA at the bottom of my workshop trashcan that represents a lot of mistakes.

Anyway, here is the original video I posted to nute's Redshift build thread. I have since updated the design a bit, and that will be detailed in post #3. The first guinea pig, er, lucky recipient of these things will be rockdoc, because he has a launch coming up this weekend. I have spent so much time playing with the 3D printer, I mean, uh, designing these things that I have neglected to even start my own 38mm rocket and will have some difficulty being ready for this month's MDRA launch. I have promised a few sets of these to some people and you'll be receiving those if rockdoc's experience is a good one.

Comments are welcome and appreciated.

[video=youtube;S2fWMos7UCE]https://www.youtube.com/watch?v=S2fWMos7UCE[/video]

When does commercial production start? I'm thinking sets in common sizes from BT-20 through 2.6" or maybe 3".

I'm seeing these being used for hi-perf MD flights. I'm not sure how well they would work for 3" or 4". Might need to be cast aluminum for that or considered single use.

Great job!

Here is what I am calling Rev A, and this is what I will be sending to rockdoc. I changed the design so that it can be printed without support material (which reduces the print time and material usage by about 50%). I also modified the rubber band hook to aid in retention so that we don't end up with rubber bands all over the field. Lastly, and I think most importantly, I made a small adjustment to the rail button geometry which seems to make it slide much more freely on the rail and which I think will allow for more rubber-band tension, which could be important with Vmax/Warp9 type launches.

[video=youtube;YlyPewS5V2I]https://www.youtube.com/watch?v=YlyPewS5V2I[/video]

Very nice work Mr. Cook. Me like!

I still think these are going to be a game changer for the guys that fly minimum diameter but don't want a tower. That's 100% of the reason I have not built a 38mm min-dia is the need to build/borrow/steal a tower. Very well done!

Love it. Great idea. These would also work as a retrofit for launch lug rockets. I'm currently waiting on some 1010 rail to try out some fly-away guides I got from another TRF member.

This just shows the whole idea and concept of a 3D printer and a forum sharing the ideas. I love it. Send me some too the UK please.

I am looking forward to testing the fly away rail guides, thank you Bill. I've flown HPR out of towers and was offered to fly out of a launch tube as well. These, will be another option and a good one for those that like to fly minimum diameter. Years ago in the old Tripoli magazine there was an article on "fly away launch lugs", which worked for me quite well in it's time, though ancient compared to what Bill is offering. I'm sure these will be a game changer for those of us that fly minimum diameter. Will post results after launch this Saturday.

Tonimus said:

I'm currently waiting on some 1010 rail to try out some fly-away guides I got from another TRF member.

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I'm curious what they look like

Great idea, much better than the one I was thinking of.
Can you design one as a standoff for HOJO type rockets as well. That would also open up another hole area of builds.

pythonrock said:

Great idea, much better than the one I was thinking of.
Can you design one as a standoff for HOJO type rockets as well. That would also open up another hole area of builds.

Click to expand...

I can't think of any reason why not.

The first step, though, is to see if they actually work...

I'm planning a small MD 54mm and was going to get stuck with rail buttons since I don't feel like building a tower. If these work I would love to try the 54mm version.

Looking forward to seeing these in action! Rockdoc, where are you launching this weekend?

Ravenex said:

I'm planning a small MD 54mm and was going to get stuck with rail buttons since I don't feel like building a tower. If these work I would love to try the 54mm version.

Click to expand...

If they work for 38 I'll start working on 54...

wfcook said:

If they work for 38 I'll start working on 54...

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I felt that was a fair assumption to make.

I could use the 38mm on a couple of my rockets, but I'd be really interested in a 3" version (as a retrofit for my KK, my new Punisher, and for the ARILSS-K rocket I hope to build this year.)

Are you looking at making these as a product you sell, or are you planning to release the STL files for folks to print their own? (Just curious.)

have you thought about instead of using rubber bands, to just print the sled so that it surrounds the rocket? And also do you have any thoughts on the strength of the PLA and whether it will hold the rocket to the rail if the angle of attack is too great?

They are held on by rubber bands?

I’m guessing that somewhere someone has successfully done this before because never in a million years would I believe that two rubber bands would hold those guides onto a high power rocket as it accelerates up that rail.

Good luck and if they do indeed work as advertised I’d be interested in a couple of sets; it would give me an excuse to build a 38mm minimum diameter rocket.

Because as we all know; you just have to have an excuse to build those types of rockets.

rbelknap said:

Are you looking at making these as a product you sell, or are you planning to release the STL files for folks to print their own? (Just curious.)

Click to expand...

To be honest I have no clue, but probably I'll just post the STL files. I don't have the capacity to print a zillion parts in a production-like setting.

boomtube-mk2 said:

They are held on by rubber bands?

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Well, the guides themselves go 3/4 of the way around the rocket. The bands are there mainly to pull the guides apart and away from the rocket as quickly as possible.

My sense of things is that they will work, but of course testing is the only way to find out...which is why distribution is very limited so far...

junkyard said:

have you thought about instead of using rubber bands, to just print the sled so that it surrounds the rocket? And also do you have any thoughts on the strength of the PLA and whether it will hold the rocket to the rail if the angle of attack is too great?

Click to expand...

The bands are there mainly to pull the guides apart and away from the rocket as quickly as possible.

The problem with going all the way around is that it is difficult to impossible to print one set that will work for multiple rockets. Every type of tube has tolerances, and being off by even a small percentage would make them unworkable I should think.

Great idea!
Look Great!
29mm, 38mm product any one?
I would buy two or three of each!
Andrew Diehl?

What's the orientation of the parts as they're being printed?

I have a project that could use 38mm and another for 54mm size fly away rail guides.

Would using elastic instead of a rubber band help overall or not ?

Kenny

etoyoc said:

Looking forward to seeing these in action! Rockdoc, where are you launching this weekend?

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Testing them while the TARC team is flying Saturday and see how they work. I'll be testing them again at the Michigan launch later in January as well.

Okie Dokie, looking forward to seeing you at the Michiana launch then in a couple of weeks!

jmight said:

What's the orientation of the parts as they're being printed?

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Upright. No support material required for the latest iteration.

I'll add another "three inch, please" though my application would be for a scale model that will be using an Estes Leviathan as the main parts donor...with the intent to fly it at NARAM-57.....

I want to thank Bill Cook for coming up with this design and am pleased to be able to give them the beta test round of testing. Here we go folks. Received the fly away rail guides today and they look great. I'm using a Madcow mini AGM 33 pike for the test subject. After unpacking the guides, they are finished in a pink plastic, easy to find and the fit is very good around the 38mm airframe. Also included were different types of rubber bands, small skinny ones which you would need 2 of and larger bands which you would need only 1. I placed the guides around the airframe to see how they fit and they are a perfect fit. I next put the rail guides in the rail channel and then placed the AGM pike into the "cradle" that the guides form and then placed the 1 larger rubber band around the 4 "band holders" at each corner of the guides. One nice feature is that the part the rubber band slides over is rounded over with a small gap where the band slides into. Once the guide was in place I slid the rocket up and down on the rail and there was no tension, and it slid up and down on the rail easily. The next test was a dry run of how the rail guides would work after leaving the rain, and it worked as expected not powered and the rail guide flew off the rocket and both pieces remained intact on the floor due to the rubber bands still retaining both pieces. Next test will be under power, and I'll post my results. I'll also be at the Michigan launch on the 18th for those that want to see and if you have any 38mm rockets you want to try them with, I'd be happy to show you how they work.

This is the view of the rail guides out of the box

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View of guides on rail minus rocket and bands

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View of rocket on rail secured to rocket with large band

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Side view of rocket on rail with guide

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Another view of rocket on rail

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Close up of rail guide on rail

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Rail guide with large rubber band I opted to use versus the smaller ones.

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grouch said:

I still think these are going to be a game changer for the guys that fly minimum diameter but don't want a tower. That's 100% of the reason I have not built a 38mm min-dia is the need to build/borrow/steal a tower. Very well done!

Click to expand...

For sure. Where were these a year ago when I needed them for my 38 MD project?!?!?! I went off on a wild goose chase to design/construct a tower contraption that took longer to build than the rocket itself! It is cumbersome and collects dust for 11 months of the year!