Rocket Plane

[bob]

I've been trying to find info about using rockets to fly model air planes and haven't been having much luck. Right now I'm more interested in plain card bored planes, instead of RC which I would like to try but not at this point. The most I've been able to find on google is this, http://www.jetex.org/cja/images/bullet-50.gif Rocket Plane (Dick Cole, 1933) Which doesn't really have much on it, what I'm picturing is something that uses a 3/8 ID rocket (small core) and looks something like this, http://www.jetex.org/cja/images/bullet-50.gif D.H. 108 Swallow (Howard Boys, 1947) So have anyone on here down anything like this or know of a good tutorial? bob

[NightHawkInLight]

Rockets have too quick a burn time to build a model plane around that would be worth flying in my opinion. Gluing some wings to a model rocket body is about as much work as I'd put into it. Pulse jets on the other hand, those make some sweet model planes. That's the route I'd pursue. If you're stuck on rockets for your project, pulse jet designs should be compatible with rockets instead.

[Anarchy08]

yeah your not the first that's dreamed this dream

 

 

you would need a long steady burn time for sustained flight, and a plane designed for a bit of speed or the wings will be ripped off

[Bobosan]

That video was cool.

 

My thoughts are building a sleek bodied glider with foldable wings that lay into the fuselage. The glider would be in a rocket configuration at take off and wings would deploy up and out of launch position when the recovery charge ignited.

 

The action would be similar to tube launched cruise missiles only with much larger wing spread.

 

When I was heavy into R/C, I toyed with this idea a bit.

Edited July 24, 2013 by Bobosan

[Carbon796]

Something like this ?

 

http://www.ebay.com/itm/Estes-T25-Centurian-RC-Rocket-Glider-New-in-Box-/261249682257?pt=Model_Kit_US&hash=item3cd3b1cb51

[Mia]

I've been trying to find info about using rockets to fly model air planes and haven't been having much luck. Right now I'm more interested in plain card bored planes, instead of RC which I would like to try but not at this point. The most I've been able to find on google is this, http://www.jetex.org/cja/images/bullet-50.gif Rocket Plane (Dick Cole, 1933) Which doesn't really have much on it, what I'm picturing is something that uses a 3/8 ID rocket (small core) and looks something like this, http://www.jetex.org/cja/images/bullet-50.gif D.H. 108 Swallow (Howard Boys, 1947) So have anyone on here down anything like this or know of a good tutorial? bob

This may be of some interest to you http://www.jetex.org/about.html if my memory serves me right I believe the fuel pellets used were Guanidine nitrate, this may be a good project NHITL, I remember having the jet x 50 it was a good little motor and simple design.

[Arthur]

Jetex made great jet motors for model planes, they had a reasonable burn time too. I doubt that they are still available sadly.

 

If you intend to make something consider "wheel drivers" or "line rockets" or "gerbs" these are slower comps with durations to 30 seconds and a long steady thrust.

Alternatively make an RC fast delta shape and fly it in the glide after a rocket has pushed it skywards.

[kpknd]

Here's what I would do. Ram a 3/8" clay plug in one end (this is the nozzel end, put a piece of tape over it first) of your 3/8" I.D. rocket tube, then ram a solid culmn of black powder fuel about 1 to 1 1/2" long. Ram a clay plug on top of that. drill a 1/16" hole by hand with a drill bit, give it about a 1/4" core, light with a small visco bottle rocket fuse.

 

A hot fuel will do fine, I mill mine for an hour, the engine gives several seconds of burn time, a longer fuel grain will diminish the thrust as the fuel burnes farther back in to the tube. The 60.30.10 fuel sucks, do'nt use it. As an end burner, the 75.15.10 will do quite well.

 

This is what I will use on my rocket car.

[bob]

Thanks for all of your reply's guys.

@NHL just gluing on wings isn't going to work as it will most likely spin around and not really go anywhere.

@Bob this is a little too complicated for me right now.

@Carbon exactly like that, just smaller for starting out and not remote.

@Mia what does NHITL stand for?

@Arthur yes this is what I had in mind.

I shot off another one today using a 3/8inch end burning rocket and a small plane made from card bored, if I was trying for a helicopter I could claim success however that isn't the case.

so fair unless I put a very long tail for a plane on it, it goes all over the place.

bob

[Oinikis]

man, i've created planes (well, gliders), and went into science about it since i was tiny! first paper and tape, next i got some lightweigh sheet, which are used to cover ceiling. that's what i'm using. and i tought about rockets, but for some reason lost interest in pyro, and the project was abandoned. i've intended to use endburner due to long and steady, not powrfull burn, but never did that, but i designed the plane for rockets, which could glide, but also go very steady at high speeds. the point of everything is the center of the mass. did alot of reasearch on this, both testing and reading. at first let's talk about straight rectangulat wing. when the center of mass is 50 % of the wing lenght from the front of the wing(exact middle) basicly it' a parachute, which slowly (sinks) while going forward(must have stabilyzer, otherwise,it will point it's nose up, and fail). plane which will sustain it's altitude(enough speed), at the right speed needs to have weight mass 1/3 from the front of the wing. when overspeeded it needs to be even more in front, becouse the nose will point into the skies, and fail. point is (we'll talk about keeping the plane straight, with minimal stabilyzers) for airspeed 0 the center of mass should be in the center of the wing, for perfect speed (when it'll sustain it's altitude(the lift=mass)) the center of the mass should be 1/3 (from the front). for gliders, it should be between these 2 points, depending on how on how much of the mass it will sustain (will it more "sink" or will more create lift). and as i said, for overspeed, it needs yo be more in front of the 1/3. now if the center of the mass is in front too much, or the speed is too small, the nose will point down, untill it will get enought speed to sustain the altitude, more to stop falling, and it'll fly with overspeed, point nose up, waste it energy, and start falling, and the cycle repeats. when overspped, or weight of the mass is in back too much, it will do the same thing, exept first point up, then fall. basicly, gliders when launched with incorect speed will "surf" on the "wave" one with rocket will either crash, or fail, and then crash.. so, you would need small (compared to plane) rocket, or have the the center of the mass realy infront, which will basicly turn a rocket, then a falling thing with stabilyzers. with delta shape wing, and with "bent back" wing is a bit more complicated, but the same rules apply, just finding these 2 points might get bit difficult. so yeah, i would go for a plane with small and long endurber rocket, which will sustain, rather than super fast horizontaly going rocket with stabilyzers. btw with magic of centers i manage to create flying wing, easily. the perfect airspeed will be figured out, with putting the center of the mass at 1/3, and throwing it multiple times and cheking, at which speed it'll fly straight.

 

 

TL;DR the point is in the center of mass!

 

and yeah, maybe too much text

Edited July 25, 2013 by Oinikis

[kpknd]

I bet you could tape an engine to one of those cheap balsawood gliders and it would work.

[SekndAmendment]

It's tough because lift coefficients are determined by airspeed via the Reynold's number. If the rocket thrust is quite large relative to the mass of the airplane then you're likely going to lose control authority and it's going to go ballistic for a bit until drag forces slow it down enough to regain control. I've built some pretty neat gliders from the ground up but as I'm sure you could imagine, glider design is a completely different ball-game than rocket plane designs. I would recommend purchasing an electric RC airplane and then rigging up some sort of radio frequency igniters and taping motors to the fuselage. Otherwise I would build a glider and put rocket motors on it that are pretty small compared to the plane. If you get too much thrust on it, glider wings lose performance quickly and you'd be better off having something with a much smaller wingspan and shorter chord length. If you pull it off though, I'd love to see some videos of it! Best of luck

[Oinikis]

in this project lift ceoficients, and whole lift are not important. the point is to build a glider, which will remain stable when overspeeded, and which will then glide nicely and stable, even in wind. so the center of mass is more important.

[FlaMtnBkr]

For some reason I want to say rocket powered model planes are illegal for some reason? Don't know why but it seems like I read that when I have seen this subject before.

 

Probably not something to worry about if you have plenty of private property to fly on, but something you might look into?

[NightHawkInLight]

It's illegal to use pyrotechnics on any craft that's remote controlled in the states. That said, I doubt the federal government is going to take interest unless it gets to be a pretty darn advanced project.

[FlaMtnBkr]

That's right. It wasn't a rocket propelled plane. It was R/C planes with pyro rockets that are remotely ignited.

 

Both sound pretty freakin fun.

[SekndAmendment]

in this project lift ceoficients, and whole lift are not important. the point is to build a glider, which will remain stable when overspeeded, and which will then glide nicely and stable, even in wind. so the center of mass is more important.

 

You don't design aircraft with lift coefficients as design parameters, you're right. You pick an airfoil profile, typically a flat-bottomed NACA airfoil or perhaps a Clark-Y for gliders, and that determines your lift coefficients. After that, your design parameters are planform area, CG location and mass. In a sense you're correct. You optimize a glider by moving its gravity center ahead of the center of pressure to create dynamic stability. My previous comment was geared more towards pointing out that gliders have a much larger wing span than typical aircraft because overall lift is generated at much lower flight speeds. When you add a rocket motor to a glider you're going to increase the velocity dramatically. Lift is defined as L=1/2*p*v²*S*C_L. Where C_L is lift coefficient, p is density, v is velocity, and S is the planform area of your wing. Lift increases with velocity squared...so if your velocity starts to increase significantly, the lift gets completely out of control. Typical horizontal and vertical tail volume ratios for a glider may have trouble coping with that much lift and you're not going to be able to keep the nose down. If any roll whatsoever is introduced then the aircraft will end up in the dirt unless you're starting with tons of altitude.

 

The only thing I wanted to point out with my last comment is that once the rocket lights you're probably going to lose the ability to steer the aircraft until the rocket burns out and drag forces slow you down enough to get rid of all the extra lift. I'm not saying it won't work. I'm merely saying that high speeds on a glider will guaranteed produce way more lift than you're bargaining for and if you don't have the proper dynamic stability you won't be able to recover. Also, I typically shoot for CG on the quarter chord of the wing. Not 1/3 from the leading edge.Throw in a bout 7-14 degrees of dihedral and that's all you need for roll stability.

[Arthur]

I'd look at a form like the Avro Vulcan. The delta is resistant to high speed drag and flies with a good speed range. Something like foamex or gator board come to mind.

 

Model aircraft that fire projectiles upset most civil legislations. Given a suitable site and maybe model flying club then flying a rocket plane may not be too problematic.

[bob]

Here is the picture of the plane that I made a few days ago, you know the one I said flew like a helicopter. It had a six inch wing span and had a 3/8 inch rocket.

Am going to try one with a much less power full rocket soon.

bob

[Bobosan]

A bit of airfoil would help with lift. Might also try to extend the tail. A 1/4" or 1/2" balsa stick would provide longer fuselage for directional stability. Just glue the tail feathers to the stick and balance it out with rocket motor installed.

[FrankRizzo]

A buddy and I tried this. It didn't work out so well; kinda flipped through the air a few times... the CG and CP weren't really in the right spot.

 

http://www.pyrobin.com/files/Rocket%20Science.jpg

[Helipilot]

I've been flying a rocket powered glider/plane for two years now. I have it mounted on a Radio controlled mother ship and take it up around 200' and let it go. It glides back to earth by remote control and just before it lands I have an electric ignitor that I trigger and it ignited the motor. It a blast. I have been using Aerotech reloadable motors for gliders. Here is alink to the plane that I ahve been using http://www.randrmodelaircraft.com/R&R%20RC%20Rocket%20Planes.htm

[karliWadt]

Perhaps putting the rocket inside the plane? Like bore a cavity into the tail and have it exhausting from the center. May need a bigger donor plane though. About 4 years ago i adapted a model space shuttle to have functional SRBs with BP and a rocket candy main engine using a rudimentary delay.... Not going to lie it went SPECTACULARLY wrong. Still don't know why it went wrong apart from being built in a hurry. Kinda imagine 2 miniature black powder lift charges exploding and propelling a large smoke generator/rocket/deadly orange javelin wildly through the air then the main rocket exploding for some reason about 3 feet off the ground. My own fault for trying something that was at the time well out of my skill range!

[Bobosan]

The link that Helipilot provided also has a rocket plane under development which is kinds what I was alluding to in my post to this thread.

 

http://www.randrmodelaircraft.com/Scissor%20Flop%20Wing.htm