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        Build Log micro Virus motor glider

#1 derk Jul 22, 2010 08:17 PM

micro Virus motor glider
what do you guys do for landing gear on a model thats semi-scale but under 15 grams?
i want to do tricycle gear like the plane i'm building but i dont have wheels that small. 0.010 music wire should be plenty strong and easily shaped, but what about the wheels? they would only be about 9mm in diameter if they are scale...
here is what i am building: http://www.mcp.com.au/sinus/models/virus.html
it will be all white EPS foam with plantraco 0.9g actuator rx, a 6mm motor and 30-50mah cell. should end up around 9-12 grams. just motor and rudder control for simplicity.

thanks guys!

#2 I R Irv Jul 22, 2010 08:32 PM

The rear landing gear on the Sukhoi and Mustang are close to 9mm. If your doing a full fuse version it's gona be one sweet looking plane.

#3 derk Jul 22, 2010 08:34 PM

yeah it will be full fuse, its laminated 3/8ths white foam so the fuse should be about 1 1/8th wide. about 10 inches long so the span should be about 16-18 inches, havent scaled that out yet.

actually, it could end up around 15 grams come to think of it. but thats why i chose white foam, its light :)

oh, and at the moment, i only have 1 sukhoi tail wheel and the assemblies cost like $4 so thats $8 just for 2 wheels :eek:
i could try and cut some out of foam rubber...if only my dremel had the full chuck so i could spin them on it!

#4 derk Jul 22, 2010 10:15 PM

well, so far the majority of the foam airframe is done and weighs in at 2.7 grams :eek: thats for a 19.75 in span!!

i added 2 0.5mm carbon rods on the wings l.e. and t.e. and a square of paper at the root joint. now i am thinking i could almost get away with a 4mm geardrive rather than the direct drive 6mm. i will play with the frame and see if i can get it to balance with that on there. should be a super floater though with such a high aspect ratio. wing chord at the root is 1.75 in so thats 11.2:1 ratio

pics to come later!

#5 PiperCub49 Jul 22, 2010 10:36 PM

Do you need foam or balsa wheels? Either?

#6 Slider2732 Jul 22, 2010 10:55 PM

You might get an LRF out of this lol. Well, being as the Leaf was some while ago...ya know :)

The Virus has a look of a full sized sport glider. It's really a fun design, great choice.
Wheels of my choice for this would be a tricycle group from an ITC Microfighter. If you have one, or know someone with one, the whole 3 wheel assembly is about 1g. Hot Wheels cars would be another thought, if you sanded down the tire wall thickness. By the time you'd be done, they may be even lighter.
Or, discs of foam with a pin through. Bit of soldering to look and act like welding and the job is done by many routes :)

#7 derk Jul 22, 2010 11:06 PM

i have stuff here to make some so i think i will try that. they just wont be *as* round as i'd like lol

thats some great ideas, but no, i dont have any itc gear and solid plastic sheels would seem heavier than some balsa ones :)

i think i will do 2 layers of 1/32 balsa ca'ed with a teeny bit of brass tube in it. should do ok for this little thing.
so it looks like i am going to try it with the geared 4mm as it seems to balance fine with the gear laid out on the fuselage. i put an exacto blade in the nose and did some test glides outside, and man are those wings flexible! they are flat while stationary but flex into dihedral in flight. much like the human powered planes do :D

off to find more bits to make landing gear!

#8 Heliman420 Jul 22, 2010 11:56 PM

What i do when i need wheels... i get some old dr scholls shoe inserts or any other brand... the rubbery foam type, cut some squares quite a bit larger than the wheel needed, use a sharp 1mm rod and poke a hole roughly through the middle, them mount on a dremmel and using 120 grit paper sand to shape, use finer paper as it gets close to the desired size, makes nice light indestructable wheels for these small models... use some brass tubing for the bushing, works for me.

#9 derk Jul 23, 2010 01:15 AM

4 Attachment(s)
ok i got the landing gear finished, works great so far. i also installed the radio gear and battery and found out that i am much lighter than expected :)

total auw minus the rudder and magnet right now is 7 grams!
sooo it should fly nice and slow :D

for now, i am going to keep the whole right side removable for charging and maintenance. if its calm out i may get a chance to test fly it tonight as well.

so here are the final specs:
span 19.6 inches
length 10.3 inches
motor 4mm geared about 4.5:1
battery 30mah 1s lipo
est. total weight 7.1 grams

#10 derk Jul 23, 2010 04:40 AM

ok i did one more modification that really helped it. i glued on some medium 1/16th sq balsa to most of the leading edge, now it hardly flexes in flight and gets MUCH more of the lift from the long wings. i think now it needs a motor and battery upgrade though as it is now i have to use full throttle just to do level circles. it handles very well and shows no signs of tip stalling or anything odd. as i was flying it, the geardrive started to loosen from the foam and slowly changed the thrustline si it flew sorta crabbed :p

but by tomorrow, it should be all fixed up and waiting for a chance to test again!
when i was building it, i thought that the rudder might have been too thick, but i needed it to support the horizontal stab but it seems plenty effective to me. deflection is about 35 degrees each way.

i dunno if anyone would use it but i could do up a little "plan/guide" on how to make one. its actually fairly simple, just need the right foam parts etc.


#11 Matt D. Jul 23, 2010 11:55 AM

Where did you get the proportions/3 view etc. to be able to make this model?
I might would be interested in making a bigger model.

#12 derk Jul 23, 2010 01:15 PM

Matt, i had emailed them on how to get a hold of 3 views, and they said all the manuals have a 3 view in them :)
here is the link for the virus manual: http://www.mcp.com.au/pipistrel-usa/...s/VirusLSA.pdf
and the list of manuals, if you want to make the Sinus or Taurus: http://www.mcp.com.au/pipistrel-usa/...s/manuals.html

so after installing a 6mm motor, it really livened up! now it will take off in about 2 feet on full power! it will fly level on about 1/4 throttle and has a great climb rate.
i will try and find a break in the wind to catch some video. also now its time to decorate and add detailing.

#13 Faethor Jul 24, 2010 05:07 PM

I'd love to see plans/how-to. I've been interested in a Micro-powered-glider for some time. :)


#14 Matt D. Jul 25, 2010 05:32 PM

Thanks very much for that.
How did you do the roundish parts? Did you just guestimate?
Do you think the one with the shorter wing would be a good float plane? I know it is a motor glider....but maybe.

#15 micro_builder Jul 25, 2010 08:58 PM

That thing should float like a feather with that wingloading, nice work. Where'd you get the EPS foam? Thats not the same as standard beaded white foam is it?


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