Rocket Powered RC Space Shuttle: Failure

I know everybody clicked on this article to see the video so I might as well start with that.

AFTER! A quick warning: Do NOT launch model rockets if the grass is DRY. That is how grass and forest fires start. Other than that, just don't be too stupid.

After closely looking at the video and inspecting the Space Shuttle afterwards, it clearly looped because it is top heavy. I completely overlooked the balance of the plane in that regard and it never crossed my mind. Lesson learned. The two solutions I can think of is to cut off the stabilizer, or move the rocket engine up about half an inch. I hate the idea of cutting off the stabilizer. I dislike the idea of moving up the rocket engine. It would give less support to the rocket engine and therefore make it weaker. Even though the Space Shuttle survived, rocket engines come in packs of three so I have two left, I do not plan on trying this again. Since I took all these photos and I know people will ask, I will continue this article with how I built it. There will be helpful tips throughout this article so if you plan on trying something simular, please read further.

Overview of model rockets: I have flown many model rockets as a kid. For those of you that don't know, a model rocket is a cardboard tube the same size of the engine, a large cardboard tube, and two washer shaped cardboard sleeves that hold the big and little cardboard tubes together. There is a plastic cone on top, a metal clip to hold the rocket engine in place and also serves the purpose of lifting the rocket off of the platform, and a rubber bungie that holds the parachute to the tube which is also tied to the cone. Point is, a rocket does not weigh very much. Which is why a C6 engine can easily get a rocket 800-1000 feet into the air. I certainly do not need my Space Shuttle to get that high for it to be an enjoyable experience, but the lighter I could get it, the better.

As you can see in the video, I used a model rocket launch pad and model rocket electronics to ignite the engine. This makes it a lot simplier and I had it laying around. David used a brushed ESC to launch his rocket plane (see related article on the bottom of this page). Maybe that was what he had just laying around. I feel the need to also mention that rocket engines to not ignite instantly. I remember in high school we flew some model rockets for a class project and some of the students would push the button and then not understand why it didn't work. You have to HOLD the button. The reason why I didn't count down in my video is because I was actually having problems with it. The batteries were old and I think my wire leads might have been touching at first. After I re-clipped them, then I finally got it to go after holding the button for a while. The Flitetest Rocket Plane video looks like it launched quicker after David flipped his switch than it normally takes. It must have been the extra battery power that got the igniter hot enough quicker.

Build and tips:

Here is a photo of the engines I used. I went with the C6 because A) it was the biggest the local hobby store I went to had, and B) if this didn't work with this sized engine then I wouldn't call it a success. I shouldn't have to go with the biggest I can get my hands on to get it to work. (I know of another local hobby shop that sells D sized.) C6 refers to the power of the engine. The 3 after the dash refers to the 3 second time delay before the rocket engine explodes to release the parachute. They also make engines with a zero second delay. These engines are meant for multi-staged rockets. After the engine has been spend, it will ignite another engine attacted to it. I have never messed around with these engines and I assume that it would try to set my plane on fire. This is why I went with the engines that explode at the end of their life. I left the rocket engine mounted very loosely so when the engine did explode, it would simply eject out of the plane, leaving it un-harmed. (Which is exactly what happened. And I even saw the fire that shot out. Sorry about not getting that part on video. I got excited and turned off the camera so I could run up and see the plane.)

Here is a photo of the chart that came with the rocket engines. I don't know what any of it means either, but I thought I would include it.

Here is a photo of the bottom and wings of the plane. I wrote all of my measurements on it. I hope it is clear and tells you exactly how to build one. I looked at a few photos of the real Space Shuttle to get an idea of the ratios of the sizes of the different parts. I don't think I got an exact replica of the Space Shuttle, but I think I got pretty close. To clarify what all the numbers mean, this is 10 inches high and 8 inches across. Drawing a line centered down it, I drew a line 2 inches, 1 inch on each side of the center line, on the very top. Then 4" down I drew a line 3" across, again centered. 2" down from that a 4" wide line. 3" down from that, a 8" wide line. Then the flaps are 1" tall. I cut out a 2" wide gap to divide the flaps and make room for the rocket engine. I drew straight lines connecting all of the across lines together and cut out that shape. Later I ended up cutting off the corners on the top. I believe I left the very top half of an inch wide and went down one inch on each side. I was originally going to make a boxed fuselage, but I liked the look of the profile style and it made it lighter.

This is the fuselage and rudder. Again, I hope the measurements I wrote on it are clear. Except maybe the illegible 3" connecting the fuselage to the rudder. This is too complicated to clarify with with mere words.

Before glueing the two pieces together, cut out a spot for the rocket engine. Since this location made it top heavy (from the point where the rocket engine is), bring the rocket engine up about, oh I'd say directly above where I have mine. Maybe higher. You can balance it out by moving the electronics and battery up and down the fuselage (not to be confused with towards the nose or tail). I had all my electronics down as far as I could, tight against the wings, while having them mounted on the fuselage.

Using a cardboard toliet paper tube, make a sleeve for the rocket engine. If you glue the rocket engine in, it will destroy your plane when the end part of the engine explodes. I said it earlier, but I'm saying it again. By making this cardboard sleeve, you are making this plane reusable. Plus if it exploded mid-air, you probably can't fly it back down. The rocket engine WILL just eject out of the plane if you leave it a loose fit. Yet you do want it tight enough to hold the engine in. You don't want it to slide out while waiting on the launch pad.

Here is a photo of the cardboard tube glued in. I don't know why I took and uploaded so many pictures. I heard people love pictures. Actually, so do I. In a way, I should have taken more.

Here is a mistake I made. Like I said earlier, the rocket engine explodes at the end of it's life. I should have glued in a foamboard plug into the cardboard tube. But I didn't. So I added a piece on each side to protect my electronics from the blast. I didn't get it perfect, but it worked. You'll see in pictures futher down in this article that some black soot got through. But it didn't damage anything.

I used a couple of zip ties to make the holders to... um... hold the plane, rocket thingy to the rocket launch pad. You can also see that I used a black Sharpie to draw on the heat shield. Paint may have looked even, but heat shields don't look even. This was faster and I think it looks more realistic this way. Maybe not realistic up close, but from far away it looks good.

The mess of electronics on the Space Shuttle. At this point all I could think was "this isn't going to work, this isn't going to work..."

More of the mess.

More of the mess. Also note the corners I cut off of the nose.

Better photo of the electronics. Plus my fancy Sharpie use to finish off the Space Shuttle look. Seriously though, I quickly drew some lines and shaded a few spots because I didn't want to spend a lot of time with it when I didn't think it would survive.

I will also mention that I put the center of gravity at about the middle of the ESC. Maybe back a little further. I also found the CG  with out the rocket engine in. Since the rocket engine would have ejected by the time this becomes a glider, you do NOT want to factor it in with the CG. Not that I had the CG even close to where it should be. Not that I could possibly know since I never got to the glider phase. Nor did I even throw it down a flight of stairs to get an idea. Basically, I have no idea where the CG should be. I assume about 2/3 the length of the plane from the nose since the wings are in the back. Unlike me, check the CG from top to bottom. Try to balance the plane on your finger by the rocket engine. I will also mention that maybe having the engine where I had it for mine, but aiming it down a little bit could, maybe, also solve the top heavy issue.

Aftermath:

A little charring on the flaps. But still flyable.

Hard to see, but some black soot on the bottom of the foamboard plug. I don't think the foamboard got burnt or anything, just residue from the blast.

Some more black soot, on the other side of the fuselage, leftover from the blast. Clearly I left some little gaps, but this should prove that foamboard works fine as a plug. Remember, model rockets are made from cardboard. It isn't a real violent, fire starting explosion that we're talking about. Also, by leaving the rocket engine loose, it makes it like firing off a fire cracker on your hand with an open palm. If you glue in the engine, it would be like closing your fist.

A screenshot of the video. This is the shot I used to determine that the backflips weren't from the flaps being up. I thought maybe the force of the rocket engine reset the ESC and did something weird, but clearly not. Especially since the plane clearly was top heavy when I tried to balance the engine on my finger afterwards.

Material List:

*- Half a sheet of foamboard. I did NOT use Dollar Tree Foamboard. I have never had that stuff in my hands, but apparently the more expensive stuff that I used is denser and heavier that Dollar Tree. At least that is what I heard. I have no idea if Dollar Tree would work or not.

*- Toilet paper tube.

*- Zippy Flightmax 2 cell 500mah battery.

*- Hobby King SS Series 18-20 amp ESC.

*- Hobby King 2.4ghz 6 channel Version 2 Tx and Rx.

*- Hextronik 9gram servos.

*- Of course hot glue, zip ties, wire flags for push rods, Hobby King control horns and clevises.

Conclusions:

I think the video shows that this would have worked great, if it flew straight up. I think it would have gotten a decent height for a decent glide down. Since I never got to the glider stage, I have no idea if this would fall like a rock or fly around for a few minutes. A bigger plane would mean that it could glide for longer, but I didn't want that extra weight or extra drag. More drag means that the plane would be stressed even more from the force of the rocket engine. Possibly shattering the plane instantly. I think the point of this project is less of a great flight, and more of an easier way to retrieve your "rocket". Like I said earlier, I've flown plenty of model rockets and one of the frustrating parts of that hobby is trying to find the rocket after the wind blew it far away from the launch pad. Just a simple launch into the air, not too high, and then gliding it down to your feet would be amazing.

The Space Shuttle did survive. If it wasn't for the fact that it would just do a bunch of backflips and crash land, I could easily launch it again as is. I don't think I could fix mine, but I could build a new one with what I've learned but I don't plan on doing that anytime soon.

Thanks for reading my article. Even if all you did was laugh at the video. I thought it was hilarious. Luckily it flipped away from me and not towards me. I did aim the launch pad a little bit away from me. Another safety tip for you if you plan on trying this. Sorry that this article got so long. I tried to keep it informational without repeating myself too much.