ME-163 - this looks like fun/trouble
 

Apart from working away on the .049 Boomerang (I am laying up the second half of the cowl mold tonight - yippee!) I have been puttering with a HET ME-163, which you might call a prop-jet but using that syntax, isn't it really a "prop-rocket". Whatever. They are a popular platform for overpowering and thrashing - see YT. I am building mine with an E-flite BL32 motor (Habu motor) and some battery TBD.

So this thing has about 270 squares, 32"+- wingspan, very light glass/polyester layup but due to the egg shape it is actually plenty robust. I was in the process of glassing the wings to the airframe, when I realized that the whole thing is magically light and very stiff. At the same time I was spying an engine or two poking out of the bottom drawer, and a light came on. Why not..?

Oddly, with the engine and pipe taped in place it is almost in balance. Rx pack behind the CG and voila.. that was easy.

So online with iCare.. time to order another ME-163. This goes in the expanding production cue of glow conversions of lekkie airframes. Thanks to the proliferation of electric models, there is a wealth of stuff to cannibalize.

This will be an easy one, I figure 18-20 hours work.

- motor mount plate to match fuselage profile
- OPS .45 DF, QM40 prop (7.4 x 8-ish, TBD)
- internal pipe tunnel, Al lithoplate and some insulation I think. The pipe nearly reaches to the rear end, so I'll graft in an exhaust duct.
- bladder tank mounted midships, in front of the spar puts about 1/3 behind the CG (that'll work)
- strip the covering from the wings, cut in some reflex, 3/4oz glass cloth, beef up ailerons
- beef up servos, hinges
- glass wings to fuselage
- new canopy from soft balsa and glass skin

All this sounds heavy but it's not. I am sure the dry weight will be under 3 pounds, putting wing loading in the low-mid 20's. Totally manageable.

http://www.rcuniverse.com/forum/atta...mentid=1985827http://www.rcuniverse.com/forum/atta...mentid=1985828http://www.rcuniverse.com/forum/atta...mentid=1985825http://www.rcuniverse.com/forum/atta...mentid=1985826

That's a great looking model..!
I'll bet it's the type of model that 1 guy shows up at a club field with...then if he has a good day laying down high speed passes [especially with an electric motor] some club members will decide that they have to have one.

cool keep posting pics...

The one pictured above is just the lekkie, not the one that will get the .45 - I am ordering another airframe from iCare for the glow job.

The electric version will eventually be for flying in the community center out back where I do the parkies. Eventually, meaning after I trim it somewhere else and figure out if I actually can land it there. Depends how many pounds of batteries I guess. The .45 version is for bigger venues.

While I am waiting for the airframe I can get out the contour gauge, get profiles from this fuselage and work on the motor mount and that stuff. This looks like a pretty simple project with promises of stupid fun as a reward. The wing is deep enough for some pretty beefy servos.

This is a fairly low cost ARF airframe - $99 - $109 retail. Just a hollow shell, you figure out how to mount stuff. The wings are prepped for elevon servos of course. It's probably pretty fun just building it stock with a peppy amount of electric power. But it begs for abuse. I guessed wrong at the wingspan, it's about 36".

The wing airfoil is nothing special, not a flying wing airfoil, and needs a lot of reflex in the elevons according to the instructions. I'd like to see what can be done about that. Given the molded fuselage which saves so much work, I'd entertain cutting new wings with a flying wing airfoil.

Mjd for that Habu motor its a bit high on the KV for anything over 4 cell on that plane. I have flown many of these motors and the best all around prop was a APC "GLOW" 6x4. not the electric 6x4 but the glow 6x4. If I remember correctly it spun that prop around 34,000-35,000 on the ground. I think it was good for 4 pounds of thrust also. With that prop hand launch will be no problem and speed will be around 140. although that is a wing the fus is pretty thick. if the air frame will hold up run a Neu 1517 1.5Y on a 7.4x7.8 Carbon at around 32,000 on 6S pack and around 140 amps. This would put it over 200 pretty easily.

Sorry, I forgot there are more than one Habu. This is a Habu 32 motor - 2150kV 32 size. I guess there is a smaller Habu with a 15 size motor 3200kV, that must be the one you mean.

I was going to go 6S and 100A controller, 5 to 5.5" prop TBD.

Know anything about annular cooling inlets? So far I have this set up with a prop adapter and no spinner, and about a 1/8" clearance all around the adapter, i.e. it is sticking through a hole 1/4" larger in diameter with a rounded lip. While this opening is much larger in area than the 4 cooling holes in the motor, I am concerned how much air I can expect through there.

Yes that is true. i would still buy two of the 6x4 props and try them out. use them on the first test flight since the thrust is very high. I would think that motor would still spin it around 35,000

Yeah, I was playing with eCalc looking for possible combos, and the 6-4 is one I looked at. 1284W input on 6S 2500, 140mph pitch speed, stall thrust just over 4 lb - that should do it.

From there - 6x5.5 down to 5x5, 5.25x6.25 are all possibles.

I had one of these , I used the guts out of a 120 dollar HK ducted fan arf.. I put a 5/5 prop on the motor and it was still ballistic. I made the mistake of using a friends battery and It met its demise when I think I managed to throw the battery out of the mounting box.. Oh yeah mine was very fast with just a 4 cell 2350 for power. It was tough to hand launch..It would really waller and almost stall at launch... but once it was in the air..look out !

the annular cooling setup workt like a charm, if you keep it above 151 mph....or 149....
With such a setup speed is your friend and you can get away with amazing power from a small motor.

I'll bungee launch it. I hate wobbly hand launches. But if the static thrust is high enough and I like how it flies then maybe hand launch later.