Ethesis

I'm putting a rocket powered RC together and right now my biggest difficulty is finding a good pair of wings and an rocket engine for powering the plane. I need some advice on finding wings or rocket engines that last more than 5 seconds.

cyclops2

There is a group of National Model rocket assoc. or something close to that. All sizes and types. Great orginazation. I will try to find a web site for you.

Edit surf the web for ESTES model rockets. Should be plenty of sites to help you.

Better surf term..........model rocket association....... Turned up everything. Enjoy!

DaveFlynn

How big a rocket motor? Aerotech makes G12, I65, J90, K185, K250, M650 and M750 motors. The G12 is specifically made for rocket gliders.

RedGN

Seems like an interesting idea.

Although the acceleration would probably be too quick to try and control. Then plane would probably shoot too far to see. And lastly, it would only last a few seconds.

Nice idea though

cyclops2

Try to see on TV the annual Model Rocket championships. Some rival early NASA lift offs. Almost.

Dsegal

> Then plane would probably shoot too far to see. And lastly, it would only last a few seconds. <

That depends on the type of model. A rocket-launched glider will be looking for thermal lift after shutdown and can stay up for a while. But the foamy SR-71 that a fellow club member bought on close-out went straight up and then straight down as he was so excited by the launch he forgot to change trim for the glide!

cyclops2

Good one Dave. Reaction times need to be much faster. Rocket flights are all business.

Control surfaces CAN NOT have any give in them. Control surface " fluttering " is almost gaurenteed. Very STIFF rods or very SHORT rods do the job.
Rod holes NEED to be a SLIGHTLY SNUG fit at both ends.

Tall Paul

I watched a demo of rocket r/c flight at Riverside Airfield.
One of the pilots failed to turn his radio on.
The plane arced over and ran into a parked full-scale.
The two that launched with that one flew OK... short power burst, then glide.

lbarnes

About 5 years ago I built a rocket powered Delta plane.
The plans were from RCM and the name was LadyHawk. Powered buy 2, D size Estes rockets. I modified so that I could fire the second rocket once it was in the air.

Trimming the plane is the most important issue as it will take your breath away once it launches and You only have a few seconds to correct and bad flight issues.

I loaded the plane with 2 rockets and went to my back yard. After hand launching the plane several times to get it to glide in a straight line and the CG was where I needed to be it was ready for powered flight.

It is real important to Plug the end of the rocket motor so that no hot gases will shoot out the front of the expended rocket. This will cause great damage to your balsa and electronics.

After several flights I gave it up due to the high cost of D-12 Estes engines. MY reason was for what it cost me to get 5 flight I could buy a gallon of glow fuel and fly allot longer than the 1 to 2 minutes of rocket air time.

Good luck on your venture, it is a rush when you first light it off...




Larry

cyclops2

Agreed, Larry.

I attended a couple of rocket launches by a local group. The V2 was too realistic. The ICBM's of the USA were ok.
Still, when the V2 was roaring up, I was seeing London burning. Very few scale models have ever touced me like that one did.

Rich

burkefj

What is the weight you are expecting? I've done a bunch of scratch built depron RC rocket gliders, that use the aerotech E-6RC motor which burns for 8 seconds or so, these are 39-49" long planes, that weight around 10-12 ounces, you can definitely fly them around and do aerobatics while under boost, you don't need a lot of strength with these motors, I'm using some simple carbon strip/rod for spars for the most part. I've done an upscale Estes Interceptor, X-15, X-1, Natter, Bomarc, and ME-163 komet using these materials, and they work great, and have good glides(not competition glides, but good for scale models).

Frank

lbarnes

I cant really remember the flying weight of the Delta I built. If I remember it was about 13 - 15 oz loaded and ready to fly.

Specs are:
WS - 23"
over all fuse length - 24"
wig area - 175sq.

Here is a pics of the first one I built. If you remember I stated that YOU MUST plug the end of the rocket for the hot gas does not enter the fuse area. I also included some pics of my first flight. I didnt plug the front end of the engine[X(]


After cutting off the wings of the burnt fuse, I rebuilt and used the wings and flew some more.

What you see in the photos are 2 mini servos and a hitec 555 receiver.

Lesson learned

Larry

-pkh-

My Feedback: (2)

Estes does sell a plugged engine for boost gliders. It's a D11-P:

http://www3.towerhobbies.com/cgi-bin...?&I=LXZH29&P=7

Ethesis

I can use any type of motor, except those above E class. i think ill start out with a B class motor and then work up to an E class. my goal is to make a plane has a rocket assisted takeoff and then glides back down. the rocket will blow itself out of the tube and have a parachute attached to the end of it. hopefully, that will get rid of a lot of wieght after launch. I kwow a B class motor will not put me high enough to glide but a D class motor probably will get the plane high up. the plane is made out of foam and a the rocket tube has been layered about 3 times over, so im not too worried about a fire. Thanks for all the responses.

exeter_acres

My Feedback: (2)

Silly question... asking because I do not know...

How would a rocket powered R/C fit into the AMA model??
Would it not be an R/C aircraft with pyrotechnics, thereby not covered by AMA?

Curious?

Sounds like fun though

-pkh-

My Feedback: (2)

If you're blowing the engine out after the burn, be sure the CG looks good with and without the engine in it (and with the different size/weight engines you plan to use).

lbarnes

I would leave the engine in the glider. If you CG the plane with out a rocket and then add the weight to the rear of the plane your aircraft would be tail heavy ([:'(]).

The best way (at least the way I did it) was to C/G with a spent rocket motor. The 3-4 seconds of powered flight would not make that big of a difference on the C/G.

Your right about the plugged D11 engines, I could not find any and since this was my very first attempt a rocket power. I didnt understand that the D12-0 meant 0 sec delay pulse. I thought it meant NO pulse. That is why my first flight looked like the pictures.

After that I epoxyed the ends so it would not happen again.

Good luck and post some pics if you have them.

Larry

DaveFlynn

The ejecting motor tube works well. When the motor tube ejects it takes the nose weight with it. This shifts the CG from forward of the CP by a couple of inches (Rocket Mode) aft-ward to the CP (Glider Mode). This way it goes up like a rocket, no R/C required, then converts to a glider at apogee. I saw one that had 10 pounds of water in the nose that was ejected at apogee.

These kinds of things are best done at a rocket launch. Once you exceed 1000 feet altitude or 3.3 pounds total liftoff weight you will need an FAA waiver. There are many rocket clubs around the country with friendly people working on all kinds of rocket projects.

http://www.tripoli.org/

-pkh-

My Feedback: (2)

Well, your obviously talking about a very specific boost glider design, but show no diagrams or photos of it. There's no way to know where the OP has his engine mounted and where the CG will be before or after ejecting the motor without more details there. If he just puts the engine in the rear, after he ejects it the CG will shift forward, not back.

Like I said, you've got to watch the CG before and after the engine is ejected.

saramos

Acording to the Official 2009 AMA National Model Aircraft Safety code General section, rocket motors up to a G series size may be used provided that they remain firmly attached to the model aircraft during flight.

Scott

lbarnes

In other words no shooting off rockets from your plane.

Don't want to open a can of worms here and get off the topic of this thread...... BUT,

With that being said, I was at a scanctioned flyin last year and there was a warbird (P-47) that shot 6 rockets from the wing of his plane.

Now maybe they were bottle rockets but they were ROCKETS.

I thought that really strange because I was under the impression that any type of propelled object simulating a rocket was not allowed by the AMA.

Larry

vicman

My Feedback: (10)

You can scrape the ejection charge out of the end of the engine with a screwdriver. It's pretty simple there is a thin wax barrier between the boost and ejection charges.

lbarnes

Wish I would have known that about 4 years ago...

It would have saved me a Htec 555 and 2 servo's.

Larry

vicman

My Feedback: (10)

You didn't ask back then.

Your LadyHawk looks great BTW. I have a set of those plans that I bought and have played with that plane a good bit on the old Dave Brown Sim.

lbarnes

You mean there was a Sim program for the LadyHawk?

After burning up the first one, I cut the wings off and made a new Fuse and put it back together. My second version included a 3rd servo for igniting the second D12. By moving the throttle to full power the servo arm are would be used like a contact switch which would then apply the 4.8Vdc to the ignitor on the second rocket.

That was fun for a few times but the cost of D12's made me put it on the shelf. I sold it at a swap meet to a guy that wanted to try it. Never heard from him.

Wow I just had a idea, maybe a .049 pusher???

Have to get the plans back out.

Larry