Converting R/C Planes to rocket Power

Howdy all,

Last year I successfully converted a Multiplex funjet to rocket power. With this conversion I could fly the model on either the electric power system it was designed for or swap it out and put in a 32mm R/C RMS F or G reloads. The funjet sadly perished earlier in the year, so I was faced with the question, what to do with the salvaged R/C gear and motor casing?

I found this. The Fox Composites ME 163 Komet, perfect choice, desingned for the same power system as the Funjet and about the the same wieght and wing area and not a Foamie.

I will do a retrospective thread on how I achieved this.

Hope you find it both educational and recreational.

We continue. First up was removing the moulded tailpipe on the model as this was only 26mm diameter so needed to be enlarged for the 32mm casing. This reqired some patience as I block sanded it back so that I did not oversize the hole. I ended up under cutting the fin and tailwheel fairing by about 3mm to achieve this. See pic 2

Internally there is a bulkhead with a lightening hole conveniently centred to work as a centering ring which needs to be opened out about 5mm to accept the the engine mount tube. I did this with 80grit sand paper wrapped around the motor case, then carefully opened it out alittle more to accept the mount tube. After this was done I made some plywood plugs to block the end of the mount tube and act as a bearing surface for the rocket motor. See pic 3

Very nice project. Looking forward to some flying pictures and a flight report!

Ari.

Very much looking forward to a rocket flight. Do you have it set up for pure rocket power only, combo rocket/brushless, or swappable? It seems to have the prop in the first picture, so I presume it's one of the latter two.

Nice plane! Planecrazy can you give some specs AUW, span etc? The Fox website has little info on the 163, I liked the Ju 128 too. I have a smaller Cloud Models Komet I've been trying to sort out for a long time and it looks like the vac formed body will need to be replaced. Styrene gets brittle after a time. :dark: I love the Komet and won't let it die so am very interested in your build and reasoning thereof.


Richard

This really looks cool! Does take off from a rail like a rocket or horizontally like a plane? Years ago there was a ME-163b Komet described in R/C Modeler magazine (January 1995) that was powered by an Aerotech H-45W that took off horizontally.

Thank you all, I am overwhelmed at the interest. I will answer you in order.

Ari, I thought this would get your interest. The only flight I have done, was with the brushless motor and had to be cut short as I forgot my glasses. One very fast red smudge is hard to control. But it ended well, no wailing and gnashing of teeth.

Aviator, I've set it up so it is truly multi-role. Mission profiles include Boost/Glide/Brushless, Brushless/Boost, or any combo you can think of. If I learnt slope soaring I'm sure it would be adept at that as well. Truely the the only model I need. (You are right, I don't believe that either:wink

Tellurian, Wingspan is 37" length 25" flying wieght(minus reload) is 1100grams (I think a bit over 2lbs in your money). This includes, Typhoon 2w 25 brushless in runner, 100amp Leopard ESC, 3300mah 4s Lipo and 450mah lipo for the on board ignition and the 32mm RMS casing. Reasoning, Hmmmm because it looked like a good idea at the time. Hehe

Aerostadt, I have a set of rails I built for my Funjet I will use those for any rocket launches. For a mission on the brushless motor a good hefty hand launch was used for the maiden. There may be some radio trickery required to improve that technique. Will keep you posted as the flight testing advances.

Next up was to sort out the forward end with the brushless motor. I was going to skip this as it is covered in the building manual. A glass fibre motor mount is provided in the kit, to which the motor is fixed with screws. there are no holes provided which means you dont have to match motors to the holes available. This is then glued into the nose cone. At this point+/_ 2 degrees of right thrust needs to be built in. I just eyeballed that as I have no idea how to measure that. I did at that point put reference marks on both the nose cone and fuselage so that every time I remove or replace that assembly it goes back in the same place. Photo shows this installed

Next was the onboard ignition. Once again salvaged from the Funjet. This is a 35amp brushed esc from GWS. hooked into a the gear channel on the AR 6210 Rx with the red wire removed so only the main battery is feeding the rx from the main ESC. I have re assigned the Trainer switch on the Tx ( JR DSX9) to the gear, so holding the trainer switch on for ignition then release when we see smoke. The output leads were then fed down the cooling vents I had cut in the rear fuselage for the brushless power system. This can bee seen in two of the pics in my first post, The ignition leads have some extra length to reach the igniter and when flying brushless only I push the clip s back into the cooling vents to keep things looking a bit tidier.

Cool! Its the same size as the Cloud Models, now I'm very interested!:w: Looking at yours I think I'll fiberglass the inside of the nose as right now there is a big 30mm hole there the result of the last test phaze. The styrene is not very structural and I was stymied for a motor mount solution. Glassing the inside looks better than trying to work out some internal bracing. You said the motor assembly could be removed? I don't see how if its glued in there.

Sorry for all the dumb questions.


Richard

The kit comes with the nose cone as a seperate part, with no cutout for the propeller. I sanded this back until I had the correct diameter hole for the prop adaptor. The instructions also call for the nose cone to be glued on, I wasnt happy with that for the purposes of access for service, so once assembled I glued some spruce blocks inside the fuselage and the used 4 self tapping screws to hold the nose cone on. (I predrilled the holes for the screws to stop the spruce blocks from splitting)

With the prop adapter removed there is just enough space to get a fine screw driver onto the mounting screws to release the motor. My only concern with this set up is the possibility of the motor pulling and tearing the fibreglass nose cone. I wll keep a watch on this and if neccessary I will glue some 016 ali sheet in there to reinforce the fibreglass. Hope that explains all that.



Here is a shot of the ESC for the on board igniter. It is just mounted with servo tape to the side of the fuselage.



In case you have wondered why the squadron codes for this aircraft are not those of Wolfgang Spate's red komet, google that LZRC and see what you find.

In case there are any rivet counters out there you will have already notice the error in the squadron codes for Wolfgang Spate's red Komet. If you google this code it should take you to the friendly site from which I bought this kit and get much support and encouragement from.

So with the hard part done this is what all the electrickery inside looks like when I go flying. A comment I must make here is that if I were really serious about this I would run a much smaller battery than a 3300mah. Its in there because I have two of these for another model I own so that is what went in here. I'm certain a noteworthy loss of weight could be achieved with a 2200ish battery. But this properly managed should give some serious endurance if I feel so inclined.

Maybe I should tidy up that wiring some.:shock:

Because I know all you thread watchers out there are into the gratuitous use of photography here is another angle for you.



The markings are not supplied in the kit and I had a local sign writer whizz them up for me. The squadron code is not that of Wolfgang Spate's red Komet. Google LZRC, tell me what you find hehe.

Till next time Planecrazy

The Tellurian, I hope pragraph one answers your questions. Good luck with your cloud models Komet, that styrene you speak of sounds a bit dodgy in the least. Hope you can get something sorted for it. I'll feel like I've saved an old dust gatherer.

Awesome. You really make me want to get one, but unfortunately, they don't seem to be available in the US, and international shipping would probably be atrocious.

The nose piece was not obvious in the earlier pics, thank you for clearing that up. Yes the styrene they used was not a good grade, PET or ABS would have made a much more robust air frame. I had been thinking of taking a mould off it to either vac form a new fuze using better plastic or doing a fiber glass version. And yes the dust will need to find another home.:wink:


Richard

TheAviator said:

Awesome. You really make me want to get one, but unfortunately, they don't seem to be available in the US, and international shipping would probably be atrocious.

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If you contact LZRC down here I'm sure he will give you a good price on the frieght

Sorry chaps, the weather gods are still not smiling on us down here in the Atipodes. So I am still not able to file a flight report.

However I did my home work this weekend and got out my camera for you.



This the launch rail set up I use for a rocket powered take of. It is very loosely based on the Phoenix glider launch rails then adapted for the foldable work table. Here is a close up of the base assembly.



I will have to come up with a better stand off for this as that is still set up for my old Funjet. One other thing I have done is to put checkered panels under the wing to (hopefully)assist with orientation. I painted my Funjet similar to a Space Shuttle so I could easily see which way up it was. With the Komet's all over red scheme it is not as easy to see which way up the plane is. I hope this will help.

So, why didnt I call this thread converting a Me 163 to rocket power? Here is a quick peek at what else has been conjoured up over the winter. Launch day can't get here soon enough.

One of these is in boost mode. Guess which one?

That's a neat build. How about a pwm controlled FET instead of an ESC? They're cheaper, lighter and have terminal blocks so you can easily replace the igniter. https://www.pololu.com/catalog/product/1211

botscott08 said:

That's a neat build. How about a pwm controlled FET instead of an ESC? They're cheaper, lighter and have terminal blocks so you can easily replace the igniter. https://www.pololu.com/catalog/product/1211

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I have looked at that but I guess I got lazy and went with what I know. Payday is coming so I may try it on the Jet Vision.

Drat wouldn't you know it. First launch for our 2013/14 season has been postponed.

Sorry people but the flight tests will be delayed a week. Lets hope the weather is OK. Tomorrow, of course is looking really good. I will be getting to the park to do a proper flight on the electric motor, you can expect a report on that in the next 48hrs

Sure wish someone would start making these again:

https://jetex.org/motors/motors.html

Don't know why they aren't. They were a lot of fun to use. I used them on light free-flight planes, but these days R/C control would be easily possible using off-the-shelf equipment.

Winston said:

Sure wish someone would start making these again:

https://jetex.org/motors/motors.html

Don't know why they aren't. They were a lot of fun to use. I used them on light free-flight planes, but these days R/C control would be easily possible using off-the-shelf equipment.

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I had one of these 50 years ago. It was by far the largest of the Jetex engines. I probably assembled something wrong, because it had a burn-through at the front lid on the very first try. In any case, this Jetex engine was very heavy and only produced a few ounces of thrust. It did not have enough thrust to lift itself off the ground. A catapult system for example using large rubber bands was needed to get the model airborne. The low thrust long burn-time was then able to sustain lift and overcome air drag. The metal cases on the smaller motors got very hot (in a darkened room the case would glow red hot) and quite often the Jetex motor was mounted on the model in standing air with no construction materials nearby.

We are getting off subject, but I have thought the same thing that it might still be nice to have these motors available to use in parasite glider applications, but the hot cases might present fire hazards or safety issues.

aerostadt said:

I had one of these 50 years ago. It was by far the largest of the Jetex engines. I probably assembled something wrong, because it had a burn-through at the front lid on the very first try. In any case, this Jetex engine was very heavy and only produced a few ounces of thrust. It did not have enough thrust to lift itself off the ground. A catapult system for example using large rubber bands was needed to get the model airborne. The low thrust long burn-time was then able to sustain lift and overcome air drag. The metal cases on the smaller motors got very hot (in a darkened room the case would glow red hot) and quite often the Jetex motor was mounted on the model in standing air with no construction materials nearby.

We are getting off subject, but I have thought the same thing that it might still be nice to have these motors available to use in parasite glider applications, but the hot cases might present fire hazards or safety issues.

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Not long ago, these were available for a while, but had to be imported from the Czech Republic:

https://jetex.org/motors/motors-rapier.html

Anyway, I guess someone already plans to fill that niche market. Just saw these:

AeroTech Demonstrates 18mm RMS-R/C™ Reloads at NARAM-55

https://www.rocketryforum.com/showt...%99-Reloads-at-NARAM-55&highlight=aerotech+c3

"The C3.4T-P and the D2.3T-P reloads are “plugged” and intended only for use in radio controlled rocket gliders and cars. They do not include a delay or ejection charge and are therefore not suitable for standard vertical launch model rockets, without the use of electronic recovery system deployment."

Thats interesting I saw some old Jetex kits (I Think) in a model collecters shop a little while ago. I will go back and see if they are still there and check the burn time on those Aerotech motors. I think I saw a Saunders Roe SR 53. A perfect candidate for a boost non glider. But I now have a surplus 45mm ducted fan that needs a home

Dammit I feel a project coming on


Cheers Pete

Hi all,

Finally got a launch with the Komet today. Sadly the results were dissappointing to say the least.

Launch @ 45 degrees into a 10kt breeze the Komet left the rails in what looked like a stalled condition, did a back flip and pretty much fell to the ground. I think Im going to have to trim some wieght from the model to get this deal to work.

I have no problem with the model as it has flown very well on elecric power from a hand launch. I will get some more reloads and try using a much smaller battery for the electric motor. Im sure also that an airstart may be a better way to go.

Got a month before our next launch so we'll see what happens then.

Sorry about the dissapointing result but if we dont get it wrong we dont learn as much.

Cheers Pete

The launch didn't go off but it sounds like the plane is still in one piece so thats good. That it did a back flip sounds like the CG is too far back. Have you tried to fly it on electric with a reload loaded in the tail? The Me 163 that I have is very sensitive to CG location. Finding that spot that allows the plane to fly with a loaded rocket motor and still be flyable with it exhausted ain't easy.

Its building season up here so I need to get back to mine. Thanks for the nudge.



Richard

Hi Richard,

Further investigation of the 163 with the aid of time and amber fluid, I noticed that at some point one of the elevon horns had come adrift wth the fibreglass skin delaminated from the foam. This is inconsistant with the way it went in but does fit with the 4secs of video I had taken. Methinks that may be it got a knock in the car on the way down to Taupiri (our launch site) about an ours drive from here.

From now on it gets a seat belt.

Peter

aerostadt said:

I had one of these 50 years ago. It was by far the largest of the Jetex engines. I probably assembled something wrong, because it had a burn-through at the front lid on the very first try. In any case, this Jetex engine was very heavy and only produced a few ounces of thrust. It did not have enough thrust to lift itself off the ground. A catapult system for example using large rubber bands was needed to get the model airborne. The low thrust long burn-time was then able to sustain lift and overcome air drag. The metal cases on the smaller motors got very hot (in a darkened room the case would glow red hot) and quite often the Jetex motor was mounted on the model in standing air with no construction materials nearby.

We are getting off subject, but I have thought the same thing that it might still be nice to have these motors available to use in parasite glider applications, but the hot cases might present fire hazards or safety issues.

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It sounds like they totally sucked big time. A few ounces of Thrust? Does that even make up for the weight of the Motor? Those things sound really lame.

TopRamen said:

It sounds like they totally sucked big time. A few ounces of Thrust? Does that even make up for the weight of the Motor? Those things sound really lame.

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They weren't intended as vertical flight motors. They provided enough thrust to give a free-flight airplane a nice spiraling climb.

Refering to post #16,

After a lengthy and painful wait for motors, weather and everything else that ruins a rocketeers life I got to fly the jet vision today on an E11 motor. Flew well if not high, but with a little more trimming and tweeking I think I have a nice parkflyer here. Will need to see if I can cram some more N/s into that casing.

The local rocket supplier has a PML Nimbus set aside for me to use as a booster for a parasite set up. So that is my winter build sorted out.

Gheers Planecrazy