Low Drag Drop Away Rail Buttons 

Horizon is being worked on in the background.... :) We're shooting video as we go so we'll do an update when we have enough to cover the interesting bits.

Cheers, thank you!

Thanks. Yup, just pick them up and put them back on the rocket.

@@AirCommandRockets next you'll want to upgrade to GPS and tiny weeny parachutes. PS can't wait for horizon launch. Cheers.

Happy New Year Ralph. Thanks for the feedback, glad to hear that the rail buttons are working for you. :)

Cool good to hear. Thanks for the update. You want to make sure that the buttons sit on the brackets fairly snugly, but loose enough that they fall off easily. I had to scrape the inside groove with an exacto knife because the 1st printed layer was deformed a little more when I printed the button. Good luck.

@@AirCommandRockets Thanks, I'll post an update on the performance of these great little critters. Hey, by the way, for your readers who might be making these as well, I've found a neat trick on making these regarding where the rounded slot is. I simply choose to design around an existing hole in the Simpson StrongTie metal and then open up that hole using it as a guide. It seems to help when someone is not familiar with metal-working (as I am at the moment). Thank you again so much for sharing this great idea!

If you do end up trying the rail buttons, I'd be interested to hear how you went with them.

@@AirCommandRockets Roger that! I've picked up some steel and now just fighting with my Ender 3 to get these printed out. My printer settings are apparently off and having a heck of a time dialing this thing in.

Thanks Matt. :)

Thanks! 😊

Thanks Mathieu. You'll definitely never look back after you own a 3D printer, and you'll wonder how you were able to work without one. :)

@@AirCommandRockets yes, indeed! It will definitely make things a lot easier

Thanks Laurence, one should be able to print pretty much any rail profile and make it work with this setup.

All good questions. I have seen fly-away rail guides get impacted by the fins, especially on the more energetic flights. Yes the brackets attached to the rocket still have a little bit of drag, but much less than some rail buttons. If you can't find a button near the pad, you can just use another one, no need to waste time looking for them. They only cost around 2 cents each. We've been printing them in batches. The other main design criteria was the ability to fit pretty much any rail type you may encounter at a launch. Perhaps the rail you wanted is taken at the time and they only have a 1515 rail available... just pop on the bigger buttons.

We use the 808 #16 V3 camera mostly, but have also started using the mobius mini V2.

Thanks :) ... I couldn't resist.

Thanks, good question. It really is no different to how normal rail buttons would act. You can still pivot around a normal single button. The time it takes is minimal from the first button leaving the rail to when the second one does. While theoretically it is possible that you could pitch over, somewhat but in practice the amount of pitch is minimal.

Yes, CO2 experiments are on the road map for us. The higher molecular mass of CO2 gives you extra performance during the gas phase too.

That would be interesting... general rule of thumb is that each stage should be 5x the capacity of the next stage. That means with 15 stages, that's around 30Giga liters for the first stage. Say about 10% the volume of Sydney Harbour. :)

@@AirCommandRockets Ups, a bit underestimated. But still it would be interesting to see an estimation of deltaV. Did a quick check, 10 stages, 1kg payload, 9tons total weight, 1:6 ratio fuel/dry, specific impulse 30 (300m/s not sure if it is achievable) Total mission deltaV=2km/s. Well at least hypersonic water rocket.

No, I believe the SpaceX engineers installed them the correct way round. :)

Good question. I would say generally you don't need a guide rail if you are using a launch tube.

@@AirCommandRockets since we're using long launchtubes for our rockets we ditched the guide rail. And it works perfectly fine the rockets are flying straight.

If the guide rail is much longer than the rocket or the launchtube is bending it might be a good option to consider using a guide rail

These rail buttons weigh about the same as conventional rail buttons, perhaps 1 or 2 grams heavier. These are really intended for Mid Power rockets and up, they wouldn't be useful for low power.

Yup very true.

We've experimented with FTC tubes quite a few years ago, and chose not to pursue continued development with them. www.aircommandrockets.com/day69.htm and www.aircommandrockets.com/day71.htm

I think this is very much possible. On our record flight we went to 961m at 1150psi. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-OTArDzG2veg.html Had we used an extra 15psi we would have reached 1km. We hope to go higher when we fly our Horizon rocket as a 2 stage rocket.

I can’t wait for that event ;-)

I'm not exactly sure of what rail profile you are referring to. Do you have a dimensioned diagram of the rail profile? What size rocket are you planning to use them on? We don't have a set launch date for Horizon yet.

@@AirCommandRockets www.dold-mechatronik.de/Aluminum-Profile-20x20-B-type-slot-6-standard-lengths-425-EUR-m this rail. It would be for a homemade pyrotechnique rocket, with a 54mm OD carboard tube

@@shere_kan8329 Ok, that is just a little smaller than a standard 1010 rail. I am not sure if you downloaded the STL files from my website, but try giving the 1010_2.stl button a try. That should work but may be tight. You may have to modify the design to make the groove a little narrower.

@@AirCommandRockets all right, I'll take a look, thanks for your help

No, the buttons seem to glide fine without any treatment. Apparently there are lower friction filaments that could be used for printing.

I wouldn't expect to see much of a difference for the regular water rockets we use. This design is intended more for high performance rockets for record attempts where you are trying to squeeze out as much performance as you can. All our high performance water rockets don't use buttons, but need a launch tube or a tower to launch them.

@@AirCommandRockets ah, so the real win here is not so much for flight, but for flexibility of launch for non-high power rockets. If the bracket that's fixed to the rocket was of a standard size, you could roll up to any launch site and adapt to the local rod/rail launch system. Thank you ACR team for the humorous, hard-working and thoughtful videos.

The original design was trying to minimize drag, but perhaps the bigger benefit is the ability to adapt to different rail profiles. The bracket doesn't have to be a standard size. The buttons themselves give you the flexibility. My buttons may not necessarily fit your brackets, but as long as you have a collection of your own buttons for your brackets, then yes you should be able to fit any rail at the launch site.

If you can keep the water from freezing then yes.

@@AirCommandRockets How did I not think of that

Yes, in New South Wales

@@AirCommandRockets i thought rockets are illegal in Australia?

@@duncan7610 Nope, perfectly legal. CASA gives us the altitude clearance at our launch sites, and issue NOTAMs at the bigger events.

@@AirCommandRockets what if you live in Melbourne, is that possible? ( sorry for bothering)

@@duncan7610 Yup, here is Melbourne's rocketry club: www.tripoli.org.au/

Waterrocketscience!

Time to add a new tool to the workshop. :)

Yup, we just print them in batches, and we bring a box full.