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wbmfishman
09-20-2005, 03:48 PM
Hi,

I have a Spirit 2 channel glider. I would like to add and electric motor so I can launch it without a hi-start. I want solid preformance. I do not want cheap either...you get what you pay for. What type of motor, propeller, battery and controller do I need to get this glider up?

Thanks

Wbmfishman

wingman
09-20-2005, 11:25 PM
I converted my Spirit to electric with a Speed 400 motor, and a Graupner folding prop. I did this as I was building it, so it was easy to shape the nose to fit my hardware. I am using a Phoenix 25 amp esc, and a 1000mah 9.6 volt nimh battery. I can get about 15 to 25 minutes of cruising time if I go easy on the throttle. It climbs out well with the 400 speed if you want to get to altitude for thermaling. With my setup it is a little heavy, so I have plenty of ballast for those windy days to get good penetration. If I could go back I would probably go with Lipos though. I also have used this plane as a camera ship with an Aiptek digital camera.

Jason T
09-21-2005, 03:47 AM
Wbmfishman,

Welcome to wattflyer!

Jason

AEAJR
10-19-2005, 10:04 AM
The Spectra is the Spirit which has been electrified at the factory. It comes with a direct drive speed 600 motor and 8X4 prop. Most people feel the climb is weak and they upgrade to a geared system or brushelss. Here are examples.

Geared systems - tower
http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=600gd&FVPROFIL (http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=600gd&FVPROFIL)=++

As a higher cost, higher performance alternative, you can go to a brushless
motor/gearbox combo. Here is one example that looks like a good choice on
8-10 cells or 3 cell lithium that can handle 35 amps. On this set-up these
planes should have strong, 45 degree or better climb angles and probably an
extra climb or two.

MJ20152 MPJet AC 26/45-20 D Brushless Motor with 2.8:1 Gearbox ..... $ 68.90
An 11X8 prop should do fine with this combo.
http://www.hobby-lobby.com/brushless_mpjet.htm (http://www.hobby-lobby.com/brushless_mpjet.htm)
Advance PLUS 30 Amp Brushless Controller $ 90.00
http://www.hobby-lobby.com/jetiblue.htm (http://www.hobby-lobby.com/jetiblue.htm)

Reports are that this combo, on 7 cells and 13X7 Prop, will climb agressively. AXI 282010 outrunner brushless motor + Jeti 40 Amp controller =
$175
http://www.hobby-lobby.com/brushless-combo-axi.htm#282010 (http://www.hobby-lobby.com/brushless-combo-axi.htm#282010)

tillmas
09-15-2006, 02:34 PM
Remember that the airfoils on gliders (SD7037 included) have an optimum power ratio that provides a sweet spot for either penetrating or climbing under power. What you seek is to be flying at a point where your wing is generating a lot of lift and where your prop is running efficiently. This usually corresponds to a place in the speed range FASTER than where L/D is highest, but it results in the most efficient climb per Watt of input.

The last time I ran the numbers off the SD7037 polar, I believe that optimum speed was somewhere around 25 mph. For this speed range, the propellors with high pitch (>6) will never be taxed, and will be very inefficient at converting shaft work into thrust.

What we need (those of us who want to electrify our two and three meter gliders to avoid the winch and high start) is large, flat props that fold (e.g. a 11 or 12 x 5 or 6). Unless you want to fly fast, but most thermal ships weren't designed to outfly their aerodynamics and do aerobatics.

I'll try to find that analysis I did and post it. You can analyze/design any prop at http://www.mh-aerotools.de/airfoils/javaprop.htm.

Matt

AEAJR
06-01-2007, 12:32 AM
Hi,

I have a Spirit 2 channel glider. I would like to add and electric motor so I can launch it without a hi-start. I want solid preformance. I do not want cheap either...you get what you pay for. What type of motor, propeller, battery and controller do I need to get this glider up?

Thanks

Wbmfishman

How did your conversion come out?

RRW
06-01-2007, 08:36 PM
How did your conversion come out?Yes please, and if you have pictures of how you did it... wonderful.

Take care.

rcastro
02-21-2008, 01:04 PM
Hello,

Here is mine: spirit2m.blogspot.com (http://spirit2m.blogspot.com)