Fly-Apart Rail Guides

[Lentamental]

Anyone have much experience using fly-apart rail guides in HPR? The Apogee newsletter covered the basics here:
https://www.apogeerockets.com/education/downloads/Newsletter243.pdf

I'm working on a 38mm MD rocket and decided to go the fly-apart direction rather than add rail buttons. Do you think music wire bent over a section of BT cut in half will work? The BT is a bit thick and tough to deal with so I was thinking of using cardstock in its place.

Suggestions?

 

[edwinshap1]

i was researching this before, but i was worried about the wire grabbing the rail.

the best option i found looked kind of like this }_{. it's piece of wire bent away from eachother, a rubber band between them, and they wrap around the rocket to the rail. when the wires leave the rails, the rubberband loses tension and the wire clears the rocket. if it's one solid piece of piano wire going around, it'll stay on the rocket and create a TON of drag

 

[Sooner Boomer]

Anyone have much experience using fly-apart rail guides in HPR? The Apogee newsletter covered the basics here:
https://www.apogeerockets.com/education/downloads/Newsletter243.pdf

Suggestions?

Is there any way this could work with a rod rather than a rail? Has anyone tried? Or I guess a question as important - would anyone be interested?

 

[edwinshap1]

Is there any way this could work with a rod rather than a rail? Has anyone tried? Or I guess a question as important - would anyone be interested?

not really because a rail has the advantage of not requiring a full attachment to the rocket. a rod has to be completely surrounded by a wire or lug or whatever you use. a rail just needs something to connect into the joints.

 

[clreynolds]

Is there any way this could work with a rod rather than a rail? Has anyone tried? Or I guess a question as important - would anyone be interested?

Fly away guides (for rods, rails, etc) have been in use in competition almost as long as there have been competitions.

 

[Lentamental]

Thats an interesting point. It may be much easier to form the wire to go around a rod, and I don't exactly need the rigidity of a rail. It would just be nice.

 

[clreynolds]

They come in lots of forms, but here is one example.

Take your two wire version, joined by a rubber band or spring opposite the rod/rail, and the two ends hook into the rail like this (top view) -) (-.

Now squeeze them closer together, until they cross over each other, and they fit around a rod like this (O).

Pardon the poor ascii graphics.

 

[Lentamental]

Well here's my first attempt. Not too shabby for my first work with composites. Kevlar is nice stuff, if a bit stringy.

I'll make the other pair once I test these out. I may make an extra set just in case they get lost. I'm also gonna try attaching the two sides together to make it harder to lose.

 

[edwinshap1]

how are they attached? the idea is that they can come off to reduce drag, but it looks like you've laminated them onto the surface of the rocket?

also, the apogee newsletter designs them to be disposable (piano wire and cardstock paper). finding them on the playa will be especially difficult since it'll look like playa and estes igniters

 

[Lentamental]

how are they attached? the idea is that they can come off to reduce drag, but it looks like you've laminated them onto the surface of the rocket?

Nope, thats a piece of parchment paper wrapped around the tube. It peels right off. Zero stick to the epoxy. Its crazy really.

also, the apogee newsletter designs them to be disposable (piano wire and cardstock paper). finding them on the playa will be especially difficult since it'll look like playa and estes igniters

I'll give them a spraypaint or something and hope for the best. Red sharpie may be my friend. Or I'll attach them together so if you find one, you find both.

 

[edwinshap1]

I'll give them a spraypaint or something and hope for the best. Red sharpie may be my friend. Or I'll attach them together so if you find one, you find both.

ooh thats a good idea put a piece of kevlar between the rubberbands

though you gotta remember, they may be kicked a little ways by the rocket, or be singed, so you should bring a few rubber bands, just in case