Fly Away rail guides?

[ghostfather]

I'd be interested in your experience with the FARG that you found on Thingiverse.

It looks similar to the stuff Andrew at Additive is making, which have worked out well for me over the years. The older PLA versions were more brittle, but he's been using PET in the last few versions that I've used. Seems to be an improvement.

I've broken a few, mostly because they were somewhat loose around the airframe. I've used them for low thrust and high thrust flights without problems. I've even used them for a non-mindia rocket just because I discovered when I got to the field that I had forgotten to attach launch lugs, and I had a FARG with me that passed.

They always seem to fail at one of the hinges, which seems to be a weak place in the design. Also lost one because we were launching next to a wheat field, and it disappeared in the wheat, and have had one stolen. Though I never caught the guy, I'm pretty sure I know who it was.

Flying one of the early versions at a launch in England a few years back, when they were still a novelty, started a discussion about whether they would be allowed in level certification flights. That was one of the older PLA versions that fractured a bit coming off the pad, so it wasn't reusable. The discussion was whether the FARG should be considered part of the rocket or not, and because it failed (was damaged), would that be grounds to disqualify a level certification. My view was that the FARG could be seen as a disposable, like dog barf wadding, and that the rocket could be reflown after recovery. If the pad had been damaged at launch, it wouldn't disqualify the level. But, of course, it was my rocket, and if it had been a level attempt I would be inclined to argue in my favour. They never did agree on how it should be interpreted, but it made for an interesting discussion.

 

[Landru]

The strength vs weight vs durability is a delicate balance, and the current product line does a good job with that.

Adding material makes the guides heavier, which means more force on landing... And repeat.

The occasional damage is usually caused by very hard launch surfaces, rocks, etc. The guide should be considered as GSE, and if damaged through normal use, has nothing to do with the quality of the flight.

For anyone who has a broken guide, I have always issued replacement parts at or below cost. Shoot me an email or order a replacement using this link: https://www.additiveaerospace.com/products/replacement-components

~Andrew

 

[cerving]

I've had them break at the hinges, and also at the "waffle" pattern. I've been through five or six of them, from more than one vendor. If somebody made a formed sheet aluminum 54mm FARG, I'd be whipping out my PayPal card right now... at least I'd know that it wouldn't shatter when it hit the ground.

 

[Nick Hutton]

Andrew, I’ve not used yours before obviously, but I have looked at them. prob would have bought - but international delivery is such a lottery at present I’m just avoiding it. I also need a 29mm one which you don’t make anyway. I’m intrested to know why you use aluminium tube rathere than carbon rod? The design I’ve printed goes together with 6mm carbon rod. Do you think it’s more likely to shatter, heavier or more expensive? I can definitely source aluminium tubing here fairly easy. I’ve printed mine out of PETG so far, but once I have built an enclosure, I’m thinking about trying polycarbonate for rocket parts.

 

[ghostfather]

The strength vs weight vs durability is a delicate balance, and the current product line does a good job with that.

I haven't broken any of your newest models using PET . The ones I've broken were the older PLA models, and always just a bit loose, which usually dented the paint on the leading edges of the fins. So I'm thinking that a loose FARG sliding down with enough impact force to caused them to crack. Since I've paid more attention to having the right fit, there have been no problems.

My Australian K altitude record a few years ago used a CTI K300 and one of your 54mm FARG's. Perfect flight.

For anyone who has a broken guide, I have always issued replacement parts at or below cost. Shoot me an email or order a replacement using this link: https://www.additiveaerospace.com/products/replacement-components

Never realized you did that, but most of the broken stuff is gone. I've saved the rods and springs in case they might break on another model

 

[ghostfather]

I also need a 29mm one which you don’t make anyway.

Apogee makes models for smaller diameters from laser cut plywood, which you have to glue together. They use those small rubber bands meant for braces to open them. They are somewhat brittle and easily damaged, especially if you accidentally step on one in the grass

 

[Nick Hutton]

Apogee makes models for smaller diameters from laser cut plywood, which you have to glue together. They use those small rubber bands meant for braces to open them. They are somewhat brittle and easily damaged, especially if you accidentally step on one in the grass

I've printed the plastic parts in PETG already. Just waiting for a carbon rod. Think I'll try that first!

I've never bought from Apogee as tjhe postage costs to here were always ridiculous.

 

[ghostfather]

Andrew, you might be interested in looking into various PET filaments, as all PET is not created equal. I buy most of my filaments from a company here in the Netherlands that provides different PET formulations based on different Kodak Amphora products.


My GOTO filament is the XT type, which requires good temperature control and it strings a bit more. It's much tougher than most generic PET filaments I've used. Might be useful for your line of products, not just the FARG's.

 

[ghostfather]

I've never bought from Apogee as tjhe postage costs to here were always ridiculous.

Nick, you might look into using a remailer service. I order several things in the US (kits, parts, electronics), let them all go to an address is Florida where they repackage and bundle them together in one box, and mail that on to me in Europe. Saves lots of money.

 

[Landru]

Andrew, you might be interested in looking into various PET filaments, as all PET is not created equal. I buy most of my filaments from a company here in the Netherlands that provides different PET formulations based on different Kodak Amphora products.
View attachment 445836

My GOTO filament is the XT type, which requires good temperature control and it strings a bit more. It's much tougher than most generic PET filaments I've used. Might be useful for your line of products, not just the FARG's.

The pet im using is about the same as XT. I participated in independent testing at lehigh university, and the print parameters tended to have a larger effect compared to a particular resin within a family. Most of the data out there is for non-printed material properies and once you send it through a nozzle there are a lot of new variables which often defy the virgin material charts.