Fly away rod guide

[AcadiaRockets]

Soooo, I did some searching and did not find anything about fly away ROD guides. I have fly away rail guides for my minimum diameter 38mm stuff, but I am putting together one of the 29mm Estes So Longs and am prepping it in FULL SEND mode. Now I imagine I will launch it at my HPR meets in the LPR area. I also imagine putting my Feather weight GPS and a Blue Raven in the generous payload just for data collection. And in the interest of squeezing every meter of altitude out of it . . .I was thinking there should be a fly away ROD guide.
Anyone heard of such a thing?
Thanks,
M

 

[mh9162013]

Is this what you're asking about? https://www.rocketryforum.com/threads/what-are-our-opinions-on-fly-away-rail-guides.174230/

Relevant discussion starts at Post #10.

 

[kuririn]

Pop lug?
https://modelrocketbuilding.blogspot.com/search?q=pop+lug

 

[AcadiaRockets]

Is this what you're asking about? https://www.rocketryforum.com/threads/what-are-our-opinions-on-fly-away-rail-guides.174230/

It is! I will explore the KFLL method further!
Thanks for the fast response!

 

[mh9162013]

It is! I will explore the KFLL method further!
Thanks for the fast response!

FWIW, I've only had success with my KFLL/FALL on BT-20 rockets. The problem for me is finding a suitable material that has the right level of rigidity and springiness, but doesn't create too much drag/friction/binding on the launch rod.

When trying to use my orange foam on rockets larger than BT-20, it become too flimsy and the launch lugs can then twist on the rod creating a braking effect.

 

[SolarYellow]

Is this what you're asking about? https://www.rocketryforum.com/threads/what-are-our-opinions-on-fly-away-rail-guides.174230/

Relevant discussion starts at Post #10.

I made a KISS-FALL with the orange foam from Hobby Lobby, but had multiple unsuccessful flights with it on a BT-20 rocket. The first one, I'm not sure when/where/how/why the flight went wrong, but it went bad. The second one, the FALL definitely hung up on a fit and turned it into a low and slow, coning/spiraling flight up to ~150 ft before the FALL finally separated. The rocket was almost a lawn dart, barely got the streamer out in time. I am moving in the direction of a tower.

 

[mh9162013]

I made a KISS-FALL with the orange foam from Hobby Lobby, but had multiple unsuccessful flights with it on a BT-20 rocket. The first one, I'm not sure when/where/how/why the flight went wrong, but it went bad. The second one, the FALL definitely hung up on a fit and turned it into a low and slow, coning/spiraling flight up to ~150 ft before the FALL finally separated. The rocket was almost a lawn dart, barely got the streamer out in time. I am moving in the direction of a tower.

I think I remember your comments about your FALL/KFLL and how you had trouble getting it to work properly. I wish I could figure out why your attempts didn't go as well as mine. I've probably had about a dozen or so launches with my FALL and they have all flown just fine, except when I tried it on a BT-50 rocket.

 

[tsmith1315]

I used mine on a 2” fiberglass HPR. Rubber bands around the outside from the center lug to each end provided tension to snap it off the rocket quickly.

 

[mh9162013]

I used mine on a 2” fiberglass HPR. Rubber bands around the outside from the center lug to each end provided tension to snap it off the rocket quickly.

Pic?

I ask because any time I used a rubber band on my FALL, it created waaaaaay too much binding on the launch lugs so that they effectively turned into "brake lugs."

 

[tsmith1315]

Pic?

I ask because any time I used a rubber band on my FALL, it created waaaaaay too much binding on the launch lugs so that they effectively turned into "brake lugs."

I don’t think I have any pics, that was 1997 or so. Rocket weight was 4-5 lbs, IIRC, and flew on I motors. So the tension was needed, but not a big deal to overcome.

I’d like to try a LPR version and report, but it won’t be anytime soon. There’s a crossfire somewhere in my build pile, that would be a good candidate.

 

[mh9162013]

I don’t think I have any pics, that was 1997 or so. Rocket weight was 4-5 lbs, IIRC, and flew on I motors. So the tension was needed, but not a big deal to overcome.

I’d like to try a LPR version and report, but it won’t be anytime soon. There’s a crossfire somewhere in my build pile, that would be a good candidate.

Wow, that's a heavy rocket!

I'm using my FALL on rockets that weigh less than 40 grams...

 

[shockie]

Here's a couple of Pop launch lugs from the past, the forerunners of today's Flyaway launch lugs. You could probably 3d print these.

 

[SolarYellow]

I made a KISS-FALL with the orange foam from Hobby Lobby, but had multiple unsuccessful flights with it on a BT-20 rocket. The first one, I'm not sure when/where/how/why the flight went wrong, but it went bad. The second one, the FALL definitely hung up on a fin and turned it into a low and slow, coning/spiraling flight up to ~150 ft before the FALL finally separated. The rocket was almost a lawn dart, barely got the streamer out in time. I am moving in the direction of a tower.

Spacedog posted in another thread:

I too have received several requests for analysis of rocket flights that suddenly veered off course after launch. One was definitely the fly-away-rail-guide striking a fin, clear video evidence. A second rocket, using the same model fly-away-rail-guide, was a probable fin strike. The others were unknown causes.

It was interesting to me to see consistent experiences of fin strikes causing problems in flight.

I've thought about it a little recently and realized that one possible factor is the LE angle. On my BT-20 rocket discussed above, the LE angle was not very swept. I could easily see that a more-perpendicular LE like this might be more prone to hang up a FALL than a more swept fin, such as a Hi-Flier, Alpha, Little John, or any other number of more-zoomy looking fins that are popular. I haven't thrown my chunk of orange rubber in the trash; kept it around to help trigger the memory bank of failed experiments. Might drag it back out and try it on another rocket that seems less prone to have a problem with it.