Skeeter E (ok making a Skeeter E powered)

Started by Ededge2002, March 27, 2014, 10:01:57 PM

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Ededge2002

My recent search for a little light weight glider to put a motor on has started.  Its a Dynaflite Skeeter hand launch glider.  It has a 56 1/4" wingspan and rudder and elevator controls.  Its an all balsa kit that looks like it will build quick and be perfect for what I wanted.  I plan on putting an AXI 2212-34(740kv) 3s 800's and an 11x8 folding prop. This should be about 100W of very efficient power.
Yea 400W/lb should about do it.. But wouldn't a nice round 500 be better?

pmackenzie


I have a similar sized model, a Sunbird. It has an Astro 010 swinging a 6x3 folder.
IIRC it pulls about 4 amps on a 3S pack, and goes up very fast (not your kind of fast  :) , but more than fast enough for the structure)
If I get a chance I will check the current tomorrow, might be a bit more than that.

With such a small wing if you want it to be able to thermal you need to keep it light.

http://www.rcgroups.com/forums/showpost.php?p=6733221&postcount=436

The 3S 1320 I mentioned might seem big, but they probably weighed about the same as the current 800 cells.
I would go even smaller now, perhaps only 500 mahr. I flew it for a while using a 3S 780 "Air hogs" pack.
(Anyone remember those)

Pat MacKenzie

Bigstik

Bigstik

pmackenzie

#3
Thanks. A better looking model than it flies. (It flies OK, but the airfoil is not the best)
Covered in monokote, but for some reason it stays tight after all these years when others just go wrinkly as soon as you complete them.
Mine was built from the magazine plans many years ago, but you can actually buy a kit now,

http://www.skybench.com/index.html?http://www.skybench.com/slhand.html  Scroll down.

Skybench kits are excellent by the way.
I have an Olly III that needs the bench to itself pretty soon. Probably make an electric fuse to go along with the glider one.

Pat MacKenzie

Frank v B

Ed,  Please be careful in powering the Skeeter.


1) I flew it on 5 cells with a speed 400 direct and a 6x4 prop.  Approx. 60 watts (brushed) and it was waaayyyy overpowered.
2) It needs about (at least) 3 degrees down thrust or it will loop when applying power.  It is a flat bottom wing if I remember correctly.  The first one I built (15 years ago) was 0/0 thrust and it needed full down trim to fly level at half throttle.  The second one (10 years ago) I added 3 degrees down and it still would sky when power was applied.  Make the down thrust on yours adjustable (washers, shims, etc.).
3) Heed Pat's comment about the limit of the airframe.  The wing is tender (1/20" balsa sheeting on the leading edge, top only).  For what you are trying to do (learn to thermal), light is best by far.
4) Use the see-through covering to save weight.  With the first one I used regular Solarfilm.  The second one was the see-through.  Also, the regular Monokote may twist/bend/break the wing if it is shrunk too much.  Solarfilm is lighter than Monokote and stays more elastic.  I have some spare see-through Solarfilm if you want (red, blue).
5) Maybe we can set up a "learn to thermal" seminar with Pat at the field.  I would love to be able to read the thermals/clouds, etc.


Just my two cents worth... and yes, I give change. :D


Frank
"Never trade luck for skill"

Ededge2002

I tripped and spilled some glue last night on some of the Skeeter parts. Thank goodness it wasn't that stinky epoxy stuff!

Yes Frank I do plan on using "ultracoat transparent light" that is just 0.12oz sq' vs that moneycoat 0.2oz sq' crap that I hate anyway.  Weighing my motor vs a speed 400 it's already 7g lighter with the prop adaptor and mount. I do plan on using the motor only for climb and don't understand this "half throttle" principal you mention. Although it seems I'm using a huge prop its low kv and I want vertical climb. I will be adding down thrust to try to tame it.
Yea 400W/lb should about do it.. But wouldn't a nice round 500 be better?

piker

#6
Hey!   That looks like the wing I built last night!

electroflyer

Nice Ed,
I picked up a composite glider at the London swap meet. It is a Highlight model of the type that was popular back in the 1990's. The cool thing is I essentially used a motor from a Phase 3 jet combined with a 4+:1 gear box swinging a small folding prop, a light weight 3s battery and other parts I had kicking around. The purpose of this plane is to have a thermal queen. I have to still weigh it, but it can not be more than a couple of pounds.
 

Ededge2002

Things have been quite hectic for a couple weeks but I did get a couple moments here and there. When I haven't been pulling my hair out I've made the additional portions of the wing to complete the span and added the sheeting. I added one rib to the outboard panels so I can cover them prior to assembling them as I hate trying to get covering to stick down in a valley.

Weight is just 2.8oz(79g)
Yea 400W/lb should about do it.. But wouldn't a nice round 500 be better?

piker

Your tips are still removable?  You'll cover, then glue the outer panels on?  Hmmm....  interesting.

BTW, that friend of your's looks suspicious.  He looks like he's up to no good.

Ededge2002

#10
Yes Robert I added a rib to the outer panels to make it so they could be built and covered apart.  The covering will be trimmed to the face of the added rib that I installed with the appropriate dihedral angle.  There is still a plywood gusset that is glued to the spars within the angle.  As I plan on using transparent covering I also made a built up stab and have started working on a built up vertical stab and fin to improve over the stock slab sheet looks.
Yea 400W/lb should about do it.. But wouldn't a nice round 500 be better?

tnjeff

May I ask what size wood you used for the tail? I have a Skeeter that I'm getting ready to start on. Thank you.

Ededge2002

I used 1/8" square and 1/8"x 1/4" balsa.   I didn't go overboard trying to get perfect geometry for strength as I figure the outer frame is quite strong and I hope the light covering wont warp it too badly.  I admit I built it up mainly for looks for when I cover it with the transparent covering.
Yea 400W/lb should about do it.. But wouldn't a nice round 500 be better?