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

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Where do i send money for the 54mm version of these?????? Want them asap. Pretty please??

I asked nicely....
 
I have to take things one step at a time, but a 54mm version will be forthcoming after the 38mm version is proven. Or at least that is the plan.
 
That's great to hear. Any plans on price yet?

Well, yes, but I have no idea for 54mm yet. I hope to have more info on this in the next couple of weeks. Have to form the LLC, start the Etsy shop, send some to a vendor, agree on vendor pricing, deal with accountant, etc. And before I can make 54mm guides and see what the time/material realities are I have to build a new printer.

I didn't start this process with the idea that I would be making more than one or two sets, but I'm in up to my neck now :). Having fun though.
 
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Well, yes, but I have no idea for 54mm yet. I hope to have more info on this in the next couple of weeks. Have to form the LLC, start the Etsy shop, send some to a vendor, agree on vendor pricing, deal with accountant, etc. And before I can make 54mm guides and see what the time/material realities are I have to build a new printer.

I didn't start this process with the idea that I would be making more than one or two sets, but I'm in up to my neck now :). Having fun though.

As long as you're having fun with it then keep it up. I think the idea is excellent. I am building a 54mm minimum diameter and was going to do a magnetically retractable rail button set up but once I found this, I pretty much threw that idea out the window.
 
Here's Stan MacDonald's rubber band powered 'fly-a-way' rail guides on a 4" M-powered rocket at BALLS...it works great.DSCN9232.jpg
 
Looks good but I still want Bill Cook's fly away rail guides for myself. Both in 38 & 54 mm.

Greg
 
Here's Stan MacDonald's rubber band powered 'fly-a-way' rail guides on a 4" M-powered rocket at BALLS...it works great.View attachment 253001

Those are similar to my original design and others I have seen (including Tim Van Milligan's), and like the others I am sure they worked. One of the problems with guides like that, however, is that the spring is linear and the force that is pulling them open is at its maximum when the guides are in the rail. Thus it is a trade-off between having a tight enough spring (an elastic band in this case) and low enough rail friction. For 38mm rockets and their motors, I judged the rail friction to be too high with this type of linear-force guide. This is why I didn't go with a torsion spring - it has the same problem.

I do understand that in the case of Mr. MacDonald's guides the buttons can be made to spin and act as a sort of roller bearing, but I am not sure that in actual practice that operates as intended most of the time. I've seen a LOT of rail buttons out there with a LOT of wear on them that shouldn't occur if they are spinning.

The advantage of the hinged guides is that due to the placement of the hooks relative to the hinge, the torque forcing them open is non-linear, and is at its maximum when the guides are open about 45 degrees. When the shell is in the closed position (i.e. when the rocket is on the rail) the outward pressure on the T-slot is very low and the torque about the hinge is just enough to force the guides open, with the torque increasing as they do so. Thus, the hinged guides achieve very low, tower-like levels of friction against the rail's T-slot during the guided portion of the boost while still springing away from the rocket very quickly when it exits the rail. It's one of those things where you sort of have to get a set in your hands to see what I am talking about, but once you fiddle with them a little bit it becomes obvious what's going on.

In addition, the hinge provides good, positive retention of the rocket within the shell.

As for the problem of fin strike, it should in reality be a non-issue. When the guides spring open, they are moving in the same direction and at the same speed as the rocket. There is not a substantial difference in velocity and in the event that the guides glance off of a fin it will be with minimal impact force. The hinged guides may in fact offer better clearance as I theorize they are less likely to tangle on anything due to the lack of a long string. Certainly with any fly-away rail guides the rocket must be shaped so that they will clear, and obstructions such as buttons or forward-raked fins would potentially be a problem, but I don't see the hinged guides having any more clearance issues than other types.
 
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Flew an AMW Purple Parrot kit yesterday using Bill's flyaway railguide prototype AMW has.
Photos here.
Worked great! G80 Skidmark to 2000+ft.

Great! I'm glad you liked them! The two reasons I started this project were (1) I wanted to do a machbusting flight but didn't want to build a tower, and (2) I didn't want to put big fat ugly rail buttons on my AMW Parrot!
 
I had a chance to test Bill,s 38mm guides Saturday at Princeton IL. They work sweet, can't wait for the 54mm & 3" versions.

Mike
 
I had a chance to test Bill,s 38mm guides Saturday at Princeton IL. They work sweet, can't wait for the 54mm & 3" versions.

Mike

Mike, I was particularly glad that you had a chance to fly with them and evaluate them. Your feedback was really great.
 
I do understand that in the case of Mr. MacDonald's guides the buttons can be made to spin and act as a sort of roller bearing, but I am not sure that in actual practice that operates as intended most of the time. I've seen a LOT of rail buttons out there with a LOT of wear on them that shouldn't occur if they are spinning.

I too see lots of rail buttons with the button worn. Often a result of the screw too tight so as to not allow the button to rotate and even when loose, if the button is in contact with both sides of the rail, that is traditionally done with two rocket mounted buttons, which direction would they 'spin'? On the guides Stan makes. they are pulled to one side and roll on one side of the rail reducing or eliminating wear...depending on the Gs at liftoff.

In addition, the hinge provides good, positive retention of the rocket within the shell.

I think your design does this nicely for 'small' rockets and perhaps two could be used for larger/longer rockets.

As for the problem of fin strike, it should in reality be a non-issue. When the guides spring open, they are moving in the same direction and at the same speed as the rocket. There is not a substantial difference in velocity and in the event that the guides glance off of a fin it will be with minimal impact force.

With a single guide they are moving about the same speed until release off the rail, and since yours is mounted right above the fins, the fins may actually help push them out of the way. With longer rockets, when the upper fly-away releases from the rocket, they may be a few feet above the fins and vertical acceleration of the guides stops at release off the rail (actually they begin deceleration) while the fins are accelerating with the rocket.

I'm not knocking your design, I think it is great for 29-75mm rockets, maybe even larger, and I plan on making some for the student teams I mentor (just last week they tore out a rail button on their 8 foot long rocket and we had to quickly install another.

Rick
 
I too see lots of rail buttons with the button worn. Often a result of the screw too tight so as to not allow the button to rotate and even when loose, if the button is in contact with both sides of the rail, that is traditionally done with two rocket mounted buttons, which direction would they 'spin'? On the guides Stan makes. they are pulled to one side and roll on one side of the rail reducing or eliminating wear...depending on the Gs at liftoff.



I think your design does this nicely for 'small' rockets and perhaps two could be used for larger/longer rockets.



With a single guide they are moving about the same speed until release off the rail, and since yours is mounted right above the fins, the fins may actually help push them out of the way. With longer rockets, when the upper fly-away releases from the rocket, they may be a few feet above the fins and vertical acceleration of the guides stops at release off the rail (actually they begin deceleration) while the fins are accelerating with the rocket.

I'm not knocking your design, I think it is great for 29-75mm rockets, maybe even larger, and I plan on making some for the student teams I mentor (just last week they tore out a rail button on their 8 foot long rocket and we had to quickly install another.

Rick

And I like Stan's design as well; there are certainly features that become more desirable as the rockets get larger and the forces get larger. At some point the weight of a plastic guide, which grows roughly with the cube of the size, does become problematic. And as things get larger tolerances allow for different mechanisms. When I get to the point of mass-producing guides for larger rockets I am sure I'll be looking at a lot of different things.
 
AVAILABILITY:

Assuming the carrier gets their act together, a limited number of the guides will be available from Animal Motor Works at the launch they are attending in Albuquerque this weekend. We're still testing some of the spicier motors (thanks, beta testers!) and my production capacity is still quite low, but I am working on those issues. In the meantime, I'd like to expand the field of testers to those willing to be early adopters. So if you are there this weekend pick up a pair, and look for them on AMW's web site. Thanks!
 
Just exactly what will be the 38mm tubing diameter the initial guides will be compatible with? If my cardboard LOC tubing is undersized, I can throw a wrap of glass cloth just proximal to the fincan so no big issue to me. Kurt
 
Do you have any plans to try to produce a 29mm set? You may be able to just scale it down in your CAD program to the right size, as long as your wall thicknesses don't get too small. I'm working on a 29mm min. diameter rocket that fly-away rail guides would be perfect for! ;)
 
Something I thought of was 24mm sizes. Wildman's BH24 is really, really too small for rail buttons, but really, really too big for a rod. It's also a pretty inexpensive rocket to put together a tower for. Fly away rail guides could help this rocket quite a bit IMHO.

Nate
 
Something I thought of was 24mm sizes. Wildman's BH24 is really, really too small for rail buttons, but really, really too big for a rod. It's also a pretty inexpensive rocket to put together a tower for. Fly away rail guides could help this rocket quite a bit IMHO.

Nate

+1. I made a cheap and dirty tower for my old BH24, which worked fine and wasn't too expensive, but it was such a pain to lug around and bring to launches.
 
Just exactly what will be the 38mm tubing diameter the initial guides will be compatible with? If my cardboard LOC tubing is undersized, I can throw a wrap of glass cloth just proximal to the fincan so no big issue to me. Kurt

The initial bunch that AMW has are sized to be compatible with Proline and Wildman 38mm thin-wall FG tubing and LOC paper tubes. I plan to add something to the instructions that says that if your tube doesn't fit, return the guides to me in exchange for a refund or a slightly different set. Some of these tubes, particularly the FG ones, tend to vary in size just enough to make things difficult for me.

I plan to also have sizes for standard (thick) wall FG tubes as well as for "flying case" rockets. I am not yet sure if I will have Blue Tube/Magnaframe or PML phenolic sizes. If I get a ton of requests, then yes, but otherwise it would have to be a $pecial order thing, probably with some increase in price.

After doing nute's guides I got a few requests for custom graphics, etc...for now I can't really do custom requests unless they are likely to go out in quantity (I.e. Someone who wants to include guides in a kit or something) . It just takes more time than anyone is going to be willing to pay for.
 
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Do you have any plans to try to produce a 29mm set? You may be able to just scale it down in your CAD program to the right size, as long as your wall thicknesses don't get too small. I'm working on a 29mm min. diameter rocket that fly-away rail guides would be perfect for! ;)

Yes! I am working on that right now, but I don't really have a timetable. It's a little more complicated than just scaling things down, unfortunately, but it's not too bad. The hardest part is sizing the diameter correctly; there is a lot of trial and error there. And I need to keep the weight down, which means making some decisions about how long the guides really need to be.
 
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Something I thought of was 24mm sizes. Wildman's BH24 is really, really too small for rail buttons, but really, really too big for a rod. It's also a pretty inexpensive rocket to put together a tower for. Fly away rail guides could help this rocket quite a bit IMHO.

Nate

I hadn't really given that much thought but I will look into it - it seems like a good idea. I plan to do 29mm and 54mm next, then see where the market takes me. It all sort of depends on how well these sell. Eventually I'd like to be able to cover most if not all of the Proline/Wildman thin-wall FG rockets. And if CTI comes out with other sizes of those cool FG-infused polycarbonate nose cones then those sizes will be targeted right away.
 
Heh. One of original reasons for doing this was to keep the big ugly rail buttons off of my (still unbuilt) AMW Parrot.

ImageUploadedByRocketry Forum1422539861.986177.jpg
 
I saw them fly today and they seem to work very well. One flight came off the rail squirrelly. It could be the wind. Maybe a 2 part guide with one above and below the fins.
 
They work pretty well, and we are trying to find their limits. There are certain configurations which I would guess don't work well: Forward-swept fins will snag the guides, for example. The squirrelly flight today was on a Talon which was flying on a CTI Mellow (very low thrust). The Talon has the leading edge of the fins waaaaaaay forward, so the guides were pretty far forward of the CG. I probably wouldn't recommend using them in that configuration - at least not when the motor has such low thrust. I'm not sure if the problem there was the motor (which I understand was actually flown accidentally) or the guides, but either way I will be adding a cautionary note to the instructions about flying with the guides mounted so far forward.

The guides are 6" long, and that might not be sufficient for a 4-foot-long 38mm rocket. I am developing a short section to mount further up the rocket for those situations just to add stability.

My wonderful beta-testers (to whom I owe many beers) are working their way up to the bigger stuff. The product is in a bleeding edge early-adopter phase right now. They are available now in very limited quantities from Animal Motor Works at a really low introductory price of $16.
 
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