Vertical landing model rocket

afadeev said:

There is nothing unique about SpaceX's one core + two boosters configurations.
They are neither the first, nor the last, to use that arrangement. You no more need to license it from them than they did from Ariane 5, or the others.

You can grab any 3 tubes + nose cones + motor mounts, attach them together (permanently, or with an option to separate), paint it white and let it fly.
Call in FalconHeavy, or rstaff3Heavy, or TramperHeavy, Big Mamma, it will still fly the same.

Your challenge will be not in the naming rights, but in moving the CP below CG, to keep the rocket flying straight and up off the launch rod. Model rockets accomplish that by hanging big fins on the tail end of the tubes.
Commercial rockets, like FH, accomplish the same by vectoring the motor thrust. Do you have the budget for that?

If not, forget about licensing issues, as your final product will, at best, bear a spiritual homage to FH.

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You are right that you can easily build the general configuration and if you don't call it by the exact name, you would be fine. All but the most scale purists would probably not care much. If you copy it to the letter for your own personal use there also would be no problems.

Gimballed motors are too much for me. Give me some Lexan and I'm good.

The problem is with short burn solid fuel motors that are non throttleable, it's very hard to reliably ignite them at the right time to slow a rocket down that may have variable decent rates based on a lot of environmental factors, and you don't want to set your field on fire. Steering is one thing, steering, slowing down without going back up and timing it all is very hard with throttling and with a very short burn.

Heavenly Hobbies Back draft. The kit that can get you banned out West!

Steve Shannon said:

Something that might work, be less expensive, and be interesting, would be to convert the rocket to an electric drone for landing.

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Done!

I've had this idea in mind for years. I remember that one day I've drawn a sketch and I kept in my wallet for... a while.
Finally, last year, I built a rough prototype. To do the tests, in order to keep a low budget, I've used water rockets, but I can swap the modules (water/pyro) in a second.
https://makezine.com/2018/03/21/dron...ds-vertically/
It has been the most challenging thing I've ever built.

Steve Shannon said:

Something that might work, be less expensive, and be interesting, would be to convert the rocket to an electric drone for landing.

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https://makezine.com/2018/03/21/drone-rocket-hybrid-lands-vertically/
I've already done a few tests using Estes Motors (simulating the same AUW) and weight distribution (CG) with very promising results.
https://youtu.be/1WNQxj7vTnM
Of course, using the Rocket Drone, I'm not going to deploy the parachute.

If a chute release can deploy a chute a altitude X, could a lower powered motor with no delay be fired at a certain altitude using a circuit controlled by the chute release to slow the descent? Looking in to using laptop hard drive motors for gyros since they are low voltage and springs/shocks from RC cars to buffer the landing gear. Looking at my stretched Big Daddy and thinking a receiver, servos, LiPo battery, and flight gyro would fit but is it feasible?

Just a random thoughts...

Knuckledragger said:

If a chute release can deploy a chute a altitude X, could a lower powered motor with no delay be fired at a certain altitude using a circuit controlled by the chute release to slow the descent? Looking in to using laptop hard drive motors for gyros since they are low voltage and springs/shocks from RC cars to buffer the landing gear. Looking at my stretched Big Daddy and thinking a receiver, servos, LiPo battery, and flight gyro would fit but is it feasible?

Just a random thoughts...

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Altimeters as used in 'chute release devices probably would not be accurate enough for last-seconds retrorocket deceleration. Better to use ground proximity sensing, either with a cheap ultrasonic sensor module or one of the new, inexpensive laser range finder ICs combined with a microcontroller OR RC control, but the latter wouldn't be as "cool" as a fully automated system. Since only a very small drogue chute would be used to maintain a vertical orientation of the rocket airframe during descent (since the landing legs [if used] and sensor(s) would be at the base of the rocket), pre or post-apogee deployment wouldn't be as prone to zippering as usual, so pyrotechnic 'chute deployment motor delay could be used. This post has a video of a Soviet cargo airdrop using the retrorocket method:

https://www.rocketryforum.com/showt...al-landing-model-rocket&p=1672000#post1672000

Note where the rockets are attached - very important for stable deceleration AND fire prevention. Any amateur attempt at this sort of method should be done only over a fireproof surface like concrete, asphalt, desert dirt, or sand.

Also, from another post above, the problems you'd encounter beyond just proper altitude sensing:

burkefj: The problem is with short burn solid fuel motors that are non throttleable, it's very hard to reliably ignite them at the right time to slow a rocket down that may have variable decent rates based on a lot of environmental factors, and you don't want to set your field on fire. Steering is one thing, steering, slowing down without going back up and timing it all is very hard with throttling and with a very short burn.

georgegassaway said:

Yes, so many of you missed this. It is a link to Joe Barnard's test flying of a model to do just that. A model similar to a Falcon-9.

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I sure did, but won't now. Thanks for that great post.