What a propeller driven "rocket" might look like.

[Antares JS]

One question I have is recovery.
If a helicopter loses power, it's rotors will lower it relatively slowly.
If I use a large propeller, will the same sort of thing happen with my rocket?

Yes. Helicopter recovery is a thing.

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-4-Model-Rocket-Kits/Heli-Roc

 

[neil_w]

Yes. Helicopter recovery is a thing.

Yes, but probably not effective with such a small propeller as would be used for a project such as this.

 

[NateB]

For stability, a helicopter needs the tail rotor to counteract the HUGE torque generated by the fast-spinning main rotor. Otherwise, the cabin will spin too.

The torque generated by the main rotor can be counteracted in other ways too. For example, our ship has a large tail fin with stabilizers on both sides. They have an airfoil and slight cant to them. We are stable above 110kt without input from the tail rotor.

I don't know how the body shape would affect stability, but I would guess that the fins could help counteract the torque from the rotor in the same way our tail does. Something would have to be done as the aircraft comes up to speed for the fins to be effective, or a coaxial rotor system could be used. RCGroups.com might have better ideas or maybe someone has already modeled some of the aircraft posted above in this thread.

@Senior Space Cadet why can't you launch a small rocket? A nearby park with a few soccer fields or similar sized area is all you need for low power. Small model rockets aren't usually breaking any laws.

 

[Senior Space Cadet]

The torque generated by the main rotor can be counteracted in other ways too. For example, our ship has a large tail fin with stabilizers on both sides. They have an airfoil and slight cant to them. We are stable above 110kt without input from the tail rotor.

I don't know how the body shape would affect stability, but I would guess that the fins could help counteract the torque from the rotor in the same way our tail does. Something would have to be done as the aircraft comes up to speed for the fins to be effective, or a coaxial rotor system could be used. RCGroups.com might have better ideas or maybe someone has already modeled some of the aircraft posted above in this thread.

@Senior Space Cadet why can't you launch a small rocket? A nearby park with a few soccer fields or similar sized area is all you need for low power. Small model rockets aren't usually breaking any laws.

I suppose I should talk to the local law, but no clubs are currently launching in my state due to fire bans.

 

[Senior Space Cadet]

Yes, I know about the whole engine torque thing, which is why rocket one had propellers on top and bottom rotating in opposite directions and rocket two had canted fins, which may or may not be effective enough. Considering it's purpose and my design, I'm not sure a little spinning would be all that bad.
I found this while searching for motors, etc.
https://www.amazon.com/Dancing-Wing...lane+parts&qid=1593712391&sr=8-32&tag=mh0b-20
More money than I'd want to lose, so I'd need to be sure I'm able to recover.
This would be a purpose built vehicle. It would do one thing, go straight up and keep going till it can't go no more. Sounds more like a rocket than a helicopter. It's it's own thing. A rockopter. A copterrocket. I don't know, call it what you want.
Of course I don't have it all figured out! I just thought it up several days ago. It's going to take me time. If it isn't feasible or gets too expensive, I'll go on to something else.

 

[kuririn]

I found this while searching for motors, etc.
https://www.amazon.com/Dancing-Wing...lane+parts&qid=1593712391&sr=8-32&tag=mh0b-20

Add that motor to an airframe with wings and you might have something:


Here's a VTOL model R/C airplane.
After taking off vertically it transitions to horizontal flight at the flip of a switch.
One prop spins clockwise, the other counter clockwise, negating torque.
R/C technology nowadays is amazing.


And BTW, these are still aircraft, not rockets.
A prop driven craft with wings going through the air is an airplane.
A rotor driven craft is a helicopter.
Even a ram jet driven craft with wings going at mach 7 is still a plane.
Or a cruise missile. But not a rocket.
They can only operate within the atmosphere.
An airframe with wings and a rocket motor is a rocket plane, like the Bell X-1 or the Komet.
An airframe with fins or thrust vector control and a rocket motor is a rocket.
So there.

 

[NateB]

I suppose I should talk to the local law, but no clubs are currently launching in my state due to fire bans.

If there are official burn bans in place, you would want to make sure you are complying with the law.

Here in NE Indiana, it is very dry but we don't have any official burn bans or advisories yet. When they do issue burn bans, they are usually written to prohibit consumer fireworks and open burning. I haven't seen model rocketry, grilling, or contained fires prohibited. The West is probably different since the risk of wildfires is greater. Personally, I think a low power kit is a low risk, even a lower risk than backyard fireworks, and I would not be concerned with launching in a park. Even if there weren't level 1, I wouldn't launch a sparky motor right now.

 

[kuririn]

Personally, I think a low power kit is a low risk, even a lower risk than backyard fireworks, and I would not be concerned with launching in a park.

Water rockets are another option.
The caretaker will be grateful for your watering the grass.

 

[NateB]

Water rockets are another option.
The caretaker will be grateful for your watering the grass.

True, although the OP mentioned not wanting to make a water rocket. I had a few when I was a kid and we built some powered by 2 liter pop bottles in 8th grade science class and had a lot of fun with them.

 

[kuririn]

True, although the OP mentioned not wanting to make a water rocket.

Yeah, the OP said "water rockets (yawn)" but you can go as mild or as wild as you want.
The Quest and Apogee water rockets might be "yawn" but check out this video:

World record 3155'.
@ 1000 PSI?
I can see why they were so far away from the launch pad.

 

[srv]

1

 

[GlenP]

Another Cub Scout race is called the Space Derby, prop power “rockets” travel suspended on a line. For example:

https://www.scoutshop.org/space-derby-kit-17095.html

 

[NateB]

Another Cub Scout race is called the Space Derby, prop power “rockets” travel suspended on a line. For example:

https://www.scoutshop.org/space-derby-kit-17095.html

Wow, that would have been fun. I made a few pinewood derby cars and a CO2 powered race car over the years for a Chruch group and school projects, but nothing quite like that

 

[georgegassaway]

FWIW - Alphonse Penuad designed a "toy" rubber band powered model helicopter around 1870, which was little more than a lightweight wood structure with two props (one at each end), powered by a twisted rubber band.

Even the Wright Brothers had a version of this when they were kids.

In the late 1960's, I had a North Pacific brand "simple" version of the same design, using the classic red plastic propellers (one was modified) from their Sleek Streak, as well as the same kind of balsa fuselage stick as used for the Sleek Streek. Didn't climb too straight. When the rubber band ran out of power, it sort of flutter-tumbled to the ground. I THOUGHT that I bought that from North Pacific. but I can't find any trace of it on the internet, and I ran across an impressive 1966 advertisement of everything they offered. At one time I had a few Sleek Streeks, so now I wonder if maybe in my experimenting with them if I might have cobbled that double-propped copter together on my own, gluing a prop to the fuselage.

In the last 3-5 years, I do recall seeing some electric motor/prop powered "rockets", but IIRC they just had 1 motor and prop on the nose, and the fins helped prevent too much of a torque roll (as well as stability). Think they used super-capacitors of something like that, which only ran a few seconds, and going up 100-200 feet. But, IIRC the "descent" was not so good. Also, while some were homemade, I think at least one was sold commercially.

Ah, OK, found one, Hackaday.

https://hackaday.com/2019/05/07/supercapacitors-propel-rocket-to-the-skies/
Now, for me, if the rocket has propellers, I prefer 4-propeller powered rockets (that once in awhile uses a rocket motor too). Lands softer too. USUALLY.

 

[GlenP]

The converse of this would be a “rocket” powered rotor blade. Or tip-jet powered helicopter. The forced air nozzles at the tip of the rotor blade is essentially a thrust from reaction type of rocket propulsion.

https://en.m.wikipedia.org/wiki/Tip_jet

Kind of reminds me of a single engine powered monocopter model rocket, the motor is balanced opposite a single rotor wing.

 

[dr wogz]

https://en.wikipedia.org/wiki/SNECMA_Coléoptère
https://en.wikipedia.org/wiki/Fairey_Rotodyne