Thoughts on a VTOL type rocket with spinning fins?

Hi,

I'm brainstorming some odd rocs and I'm entertaining the thought of having a rocket designed like a VTOL with spinning fins on the end.

Like this from the Captain America movie:



However I would have the motor in the bottom/body tube as usual and there wouldn't be propulsion on the ends of the fins.

I figure maybe a ring around the fins (like those little flying disc helicopter toys) in addition to a set of standard fins for stability above or below the spinning fins. Has this been done yet?

Thoughts?

Take a look at this for an article and buyable paper model of the real thing, the Focke-Wulf Triebflügel:
https://www.fiddlersgreen.net/models/Aircraft/Focke-Wulf-Triebflugel.html

The main problem with the model you propose is that if there's any friction between the spinning fins and the main body then the whole model will spin. But there is a way round this - sort of...

Back to reality, where Britain experimented with the idea of a tip-powered rotor, starting with the Fairey Jet Gyrodyne:
https://en.wikipedia.org/wiki/Fairey_Jet_Gyrodyne
And then proceeded on to what would have been a commercial aircraft if it hadn't then been cancelled, the Fairey Rotodyne:
https://en.wikipedia.org/wiki/Fairey_Rotodyne
These aircraft were laid out more like conventional helicopters, with the rotor mounted on top of the fuselage, and with a pair of wing-mounted propellors to drive the aircraft in forward flight once the rotors had got it off the ground:


Of course, the fuselage and wings like that aren't going to be very useful to a flying model rocket, so let's get rid of them. And what we're left with is Scroton:

That wasn't mine. At least, the rocket wasn't. The launch pad was,and when that beast took off, it tried to take the pad with it, which wasn't going to end well because the pad was pegged to the ground, so Scroton only got away with the launch rod. I managed to repair the pad, and next time the owner sent Scroton off a much shorter rod. This worked so well that he decided to increase its power by putting a triple cluster on each end, and the resulting force sent it off in three directions at once. So if you're going to try something like this, be aware of the limitations of your material.

Spinning lower fins would cause the whole model to spin and the Drag induced would likely make the model have very short flights.

I have a 1/48th POGO VTOL plastic model in my fleet that flies very well. It's front mounted counter-Rotating props do spin freely on the way up. It's takes a good bit of fuss to get these props and bearings to spin freely enough that air pressure alone causes them to rotate.

On it's best flight days this fairly heavy model only gets about 120feet on a C6 motor. Great for PMC judging and recovery but far less then would be expected without the spinning props.

It has been done before...

[video=youtube;fQ4AyUBArkI]https://www.youtube.com/watch?v=fQ4AyUBArkI[/video]

Thanks all for your interesting and informative replies!

Of note is that I'm going more a rocket loosely designed like the one in the pic I posted with a single rocket motor in the main body tube and the propeller more for show and little "go". I would decrease the pitch so that it won't be too much drag, but just enough so that it spins slightly on the way up.

Adrian - thanks for the links and info! You're really fueling my imagination; however I'm going to try to keep it simple and try some small simple tests after regular rocket flying season is over (read winter). The one that took the launch pad with it is exactly why I don't want this to be multiple engine prop-end propulsion...way too unpredictable and small engines can be so variable with thrust (something you can't allow in a system that depends on balanced, matched and even thrust). One option to brainstorm is the monopod, so the thrust imbalance effect is not an issue; however trying to mount anything in the center can be just as disastrous (but sounds exciting!)

Micromeister - That's a REALLY awesome pogo rocket! I probably would've tried something like that as a separate project; however it's going backwards from what I'm looking for, but at the same time helps get me thinking. I actually earlier thought about the possibility of counter-rotating props on the back to counter the spin effect; however I do realize that friction and drag becomes a much bigger issue and that goes against my initial thoughts of a first simple test version. Maybe a small prop in the front and a bigger (2 calibers?) rotating ringed prop in the back?

K'Tesh - Have you seen that video where in another country (India?) they launched a rocket powered giant ring that was something like 30-50' wide? Thing was a monster and actually worked! Nothing at all like what I'm going for, but still really cool to watch. Rocket porn. lol

Thanks again everyone!

adrian said:

The main problem with the model you propose is that if there's any friction between the spinning fins and the main body then the whole model will spin. But there is a way round this - sort of...

Click to expand...

Hmmm...maybe angle the fixed fins on the model to counter the rotation friction/spinning effect? Probably too hard/variable to predict or make actually work well, but an option to explore.

KenECoyote said:

Thanks all for your interesting and informative replies!

K'Tesh - Have you seen that video where in another country (India?) they launched a rocket powered giant ring that was something like 30-50' wide? Thing was a monster and actually worked! Nothing at all like what I'm going for, but still really cool to watch. Rocket porn. lol

Thanks again everyone!

Click to expand...

Thailand... Rocket porn... Best Kind o' Kink :wink:

KenECoyote said:

Adrian - thanks for the links and info! You're really fueling my imagination; however I'm going to try to keep it simple and try some small simple tests after regular rocket flying season is over (read winter). The one that took the launch pad with it is exactly why I don't want this to be multiple engine prop-end propulsion...way too unpredictable and small engines can be so variable with thrust (something you can't allow in a system that depends on balanced, matched and even thrust).

Click to expand...

It worked well enough with a short launch rod. Really short - we're talking 6", maybe a foot long. The same goes for monocopters.

K'Tesh - Have you seen that video where in another country (India?) they launched a rocket powered giant ring that was something like 30-50' wide? Thing was a monster and actually worked! Nothing at all like what I'm going for, but still really cool to watch. Rocket porn. lol

Click to expand...

Thailand. There were a couple of threads about it. Here's one:
Crazy rocket launch.....

The first time I heard the term "rocket porn" was some years ago when I was at Waltham Abbey, formerly the Royal Gunpowder Mill where various explosives including rocket propellants were made, now a museum. A bunch of us had been invited to put on an exhibition because due to their involvement with rockets, Waltham Abbey was hosting a "Rockets and Space" event. I was camping overnight but the first night they let me sleep in the marquee where some of their own stuff was laid out ready for display the following day. This led me to comment "Who needs rocket porn when you get to sleep with the actual rockets?" :lol: