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All Forums >> RC Airplanes >> RC Gliders, Sailplanes and Slope Soaring >> Introduction and Question re- electrifying sailplane
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Introduction and Question re- electrifying sailplane - 5/23/2006 6:41:06 PM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Hi there, I'm pretty new to this site, but already have found help in various areas just by searching the archives. I've been flying glow planes for a while and now I've got a question concerning a sailplane that I built years ago and want to finally get in the air. The club I belong to won't allow hi-starts so that's out, and so I want to put an electric motor and prop on it. It is a Windsurfer 100, a 2m sailplane. Although I haven't weighed my plane I found a reference on the internet that says it should be about 28oz. After a little hunting around I found a few possible solutions and would appreciate any advice I can get. The motor/folding prop combos I'm looking at are:

EFlite EFLM108 - 480 size motor, 4:1 gear ratio, 11x8 folding prop

EFlite EFLM107 - 600 size motor, 2.8:1 gear ratio, 11x8 folding prop

The one with the 480 is considerably less expensive - would this do the job or do I need the 600 size? If it's any help, I experimented with a Cox .049 with a 5x3 prop on a pod on the top of the plane and it could fly - barely, but definitely couldn't climb. I'm sure some would frown aggressively at my putting a glow motor on a sailplane but hey, I was experimenting and happened to have a .049 kicking around. Anyway, it didn't work and I'm going electric.

So, what say you folks?

Cheers,
Kerry


_____________________________

Cheers,
Kerry
       Post #: 1

RE: Introduction and Question re- electrifying sailplane - 5/23/2006 8:54:36 PM   
BMatthews



Posts: 8945
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline 		If it's a 2 meter airplane and under 30 oz then the 049 should have been enough power to make it glide uphill at least and end up at around 300 feet. Either you were too aggresive on the controls (big control inputs generate big drag prices) or you were not running the 049 on a decent fuel and prop or the engine is kaput for some other reason.

So for starters I'd suggest you find a scale and weigh the parts. Also, how much nose weight did you need to use?


_____________________________

Bruce-
Proudly wasting balsa since 1965.

Free Flighters go that extra mile........

(in reply to zoneshot)
       Post #: 2

RE: Introduction and Question re- electrifying sailplane - 5/23/2006 9:54:50 PM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Thanks Bruce

You are absolutely correct that the .049 wasn't running on the right fuel - it was just some 15% four stroke fuel that I had. I tried again using some 25% Sig fuel but the results were no better. The prop was just what was on there from when I got the motor as a gift with a control line model. I'm guessing it's nylon (white) but I could easily be wrong on that. I'm also guessing that it's a 5x3 just by comparing to some others in a store. You're also very likely correct about the amount of control movement I was applying.

Even if I could get the plane to climb with the .049 though, I really want to switch to electric (for convenience and cleanliness) so an opinion on the motors I mentioned would be appreciated too.

Cheers,
Kerry

_____________________________

Cheers,
Kerry

(in reply to BMatthews)
       Post #: 3

RE: Introduction and Question re- electrifying sailplane - 5/23/2006 9:56:33 PM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Oops, forgot to say - I'll try to weigh my plane tonight and let you know the true weight.

Kerry

_____________________________

Cheers,
Kerry

(in reply to zoneshot)
       Post #: 4

RE: Introduction and Question re- electrifying sailplane - 5/24/2006 3:48:06 PM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Turns out my sailplane weighs considerably more than the estimate I saw elsewhere. With the radio installed and lead weight in the nose it weighs in at 40oz. I epoxied the lead weight in the nose so didn't take it out to weigh it but I believe I added around 4 - 5 oz.

So, my question is still do you think I can get away with the E-Flite 480 size motor with the 11x8 folding prop? Do I need the 600 size motor? Or, is there a better alternative?

Any advice or suggestions would be appreciated.

Cheers,
Kerry

_____________________________

Cheers,
Kerry

(in reply to zoneshot)
       Post #: 5

RE: Introduction and Question re- electrifying sailplane - 5/31/2006 12:23:13 AM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Hah, I did it! I fit my plane with a master airscrew folding prop/3:1 gear/550 brushed motor combo and it flies! It did add 10oz so I'm at 50oz flying weight now, but hey, it works! I need to get some bigger batteries - the ones I had on hand are only about 850mah.

Now, to find a thermal or two...

Cheers,
Kerry


_____________________________

Cheers,
Kerry

(in reply to zoneshot)
       Post #: 6

RE: Introduction and Question re- electrifying sailplane - 6/6/2006 5:04:03 AM   
flying evader


 

Posts: 100
Joined: 3/19/2006
From: , CA, USA
Status: offline 		50oz dont sound like a 2m sailplane to me anymore.. hehe just kidding. No really, you added considerable nose weight with those 4-5 leads... I have a gentle lady that is in the 36-40oz range (depending on wind i put on or off weight).. an el-cheapo T-600 with an 8X4 with 3S LiPo really hauls it.. I do just about every manuever possible with a 3ch and polydyhedral plane with this motor.

When the T-600 wears out, I think i'm gonna go with a 480 with a geared drive and big prop..

do you have the battery on the nose and the servos as fwd as possible? you could take an oz or 2 off if you move all the weight fwd..

(in reply to zoneshot)
       Post #: 7

RE: Introduction and Question re- electrifying sailplane - 6/6/2006 5:13:04 PM   
zoneshot


 

Posts: 6
Joined: 7/29/2005
From: Fort Sask, AB, CANADA
Status: offline 		Sorry, I should have been more clear. When I added the motor and prop I took out the lead weight, so in all the plane is 10oz heavier with the motor. I had to put the batteries behind the wings to get it to balance again. Maybe next year I'll invest in LiPoly and charger etc, but for now I'm just using some 7cell NimH's I had already. I can manage to get 8 - 10 minute flights, ~3 minutes powered, 5-7 minutes gliding in dead calm air in the evenings, so not horrible. Well, someone with some experience would probably find that horrible but hey, it's a start.

By the way, any estimate how much lighter a fibreglass fuselage, or fibreglass pod and boom would be compared to built up balsa/ply? Without investing more money playing around with different motors etc, that's the only place I see a possiblility of shedding some weight.

Kerry

< Message edited by zoneshot -- 6/6/2006 5:14:17 PM >

_____________________________

Cheers,
Kerry

(in reply to flying evader)
       Post #: 8

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