Electro Skeeter

Father O 5 · Post by **Father O 5** » Wed Feb 22, 2006 12:55 pm

Finish one, start another.

58 1/2" wing, which is +10% for 2610 and within 2548 rules.

Looking to electric power so I am following the E-SSC thread. Any tips or suggestions welcome.

drewjet · Post by **drewjet** » Wed Feb 22, 2006 5:11 pm

Mike, it looks interesting. How are you making the airfoil?
Do you use any spars or just the coro as a spar?
I am looking into another mega motor that maybe a suitable cross 2548 and 2610 motor. Hope to have it by next week.

wrnstockwel · Post by **wrnstockwel** » Wed Feb 22, 2006 7:54 pm

Mike,
Looks very interesting. I assume your mocking the plane up, then untaping the the foam to cut the airfoil.
I have experimented with direct drive on Kyosho Magnetic Mayhems. The RPM starts out at around 15,500, but with 2 running in series you only need a 6s1p setup of 2000 batteries. The plane launchs fine and the motors will produce enough thrust for an almost 1:1 thrust to weight ratio, then they will unwind in a dive, just like a gas plane. The big benifit to series motors is, if one quits, so does the other, no death spiral.

(side note: The Kyosho Magnetic Mayhem has evidently been discontinued, guess they sold to many, I am currently looking for a replacement. It was a 22x1 wind motor, anyone have any suggestions?)

Scott

drewjet · Post by **drewjet** » Thu Feb 23, 2006 4:37 am

How about the endoplasma? I have a few of them laying around and will probably never use them.

Father O 5 · Post by **Father O 5** » Thu Feb 23, 2006 9:23 am

This is how I am getting the airfoil into my wings.

View of wing ready to be worked. (Upside down it kinda looks like the Bat Symbol, just an aside.)

This explains how the coro fits into the wing. I traced the outline of the wing onto the blue foam after blowing it up on the high tech copier. (no CAD here!) Then fit and cut the coro to shape. The picrue also shows the approximate position of the holes I cut to lighten the coro some.

This image shows how the airfoil gets sanded in. I am following the old principles of "if it looks like it should fly, then it should fly." I grew up on control line stunt planes so all of my airfoils have been symetrical so far. Unfortionately my building skills, such as they are, far outstrip my flying skills so none of them have been test flown yet. I am considering asking some of the Atlanta folk to be my test pilots.

drewjet · Post by **drewjet** » Thu Feb 23, 2006 9:47 am

Wow that looks like a lot of work. And seems a bit heavy. Good luck with it. I am curious to see the outcome

wrnstockwel · Post by **wrnstockwel** » Thu Feb 23, 2006 2:30 pm

Drew,
Check out my use for the Endoplasma motor in the SSC forum http://www.rccombat.com/forum/topic.asp ... hichpage=1

You could go this route with about the same results, but you have to have the geardrive. The Endo is wound so it just LOVES AMPS at lower RPM under load. Direct drive wont get it. With gear drive you wont get the down hill acceleration as much.
Ill run that option through Motocalc and see what it says.

Scott

Lou Melancon · Post by **Lou Melancon** » Thu Feb 23, 2006 3:31 pm

Father O 5,
I built a DeHavilland Hornet about four years ago and flew it in one contest. Here is the only photo that I have of it:

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I believe I still have the templates. The airfoil was a Selig 8052.

Father O 5 · Post by **Father O 5** » Mon Feb 27, 2006 1:44 pm

Anybody have any thoughts on using folding props on the electrics?

I don't know of any way to ensure that the prop ends up horizontal to the ground for landing and I thing that a folder may (??) help out on a prop strike on another plane.

Ed Kettler · Post by **Ed Kettler** » Mon Feb 27, 2006 2:16 pm

I have a Me-110 with two OS 15LAs, and it has about 8 combat rounds on it. It went through 3 iterations to get the weight down to 4 pounds even, and now flies pretty nice. With the RPMs on singles down to 14.5K, this should make the twins very competitive.

I am looking at a couple of options for twin electrics: Beaufighter and He-219. Lee has a Me-410 he's working on, and Cash got the P-70 (A-20 nightfighter) fuselage from me yesterday, so there should be some more twins on the circuit (Cash will use IC). I think a good electric setup will make twins more popular because it really reduces the 'hassle factor' of syncing the engines and there won't be a lot of launch pressure. I think Scott will be doing an electric P-70 as well.

Right now we will be using MAS 8x3 SSC props, and I'm not sure about folding props in that size/pitch.

Best of luck on the Mossie. I love that plane.

Ed

Father O 5 · Post by **Father O 5** » Mon Feb 27, 2006 2:32 pm

I know that we are shooting for 8x3 props to stay within the rules with the electrics but the nature of alot of the systems calls for bigger, slower props.

Lee is swinging a 10x4 on his 2548 Fw-190 on another thread.

I was doing some research and think I am going to give the Astro Brushless 19 Direct Drive motor a try. On the Astro site (astroflight.com) it shows 31 oz thrust on 3 Lipos with an 8x4. I cannot find an 8x3 foder but the 8x4 is pretty common. Will 61 ozs thrust fly a 68 oz plane to combat levels?

One of the things that I am worried about with the electrics is a Watt War. There are limits on motor size for IC but what is to stop E flyers from using really large motors (HiMax HC3528 is listed as a .40 IC replacement) and overpowering the field?

drewjet · Post by **drewjet** » Mon Feb 27, 2006 4:37 pm

In 2548 there is a mandatory prop. You must use an APC 10X3 or Master airscrew 10X4 for singles at 14500 RPM. For twins Master airscrew 8X3 at 17500. End of discussion, as more watts puts you over the limit. In Scale, the amount of watts will be determined by how fast you want to go versus weight. If you are pulling too many watts you won't be able to handle the weight. And I would rather fly a slightly slower plane that handles and turns well rather than an all out speed plane.

Lee Liddle · Post by **Lee Liddle** » Mon Feb 27, 2006 7:51 pm

I wouldn`t worry about a folding prop. One thing about the Mosquito is that the engine nassels are very deep and the thrust line is at the top of the nassel, so the prop would have to stick straight down to cause a problem. When the props are stopped they will still rotate enough to move when landing. You may break one every now and then, but it hasn`t been a prob for me with the electrics.

Lee Liddle · Post by **Lee Liddle** » Mon Feb 27, 2006 7:55 pm

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Will 61 ozs thrust fly a 68 oz plane to combat levels?
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

It depends a lot on wing loading. SSC`s fly at less than one to one power/weight ratio.

Give me a link to some motor specs or post some specs, that will tell a lot.

Lee Liddle · Post by **Lee Liddle** » Mon Feb 27, 2006 8:13 pm

Mike, DON`T buy those Astro motors. They are not what yoyu need. The 1350K/V rating will keep them from turning the needed rmp on 3 cells. You need a K/V of around 1900 to turn 17.5k on 3 cells.

I`ve had great performance out of my HiMax 3615-2300. It will easily turn 17.5 on 3 cells as long as the batts can deliver 30 amps continuous without the volts dropping.

The Apex 3s 2000 batts that Drew is using are only rated at 10c and I think that that is a little high. I would recomend batts that are rated at 12c. The 3615 also has the 5mm output shaft which is good.