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        Electric ASW-22 B270 from Graupner

#1 Thomas Nelson Sep 22, 2003 07:32 PM

Electric ASW-22 B270 from Graupner
 
Posted this over in the Electric Sailplane forum, but got no responses. Maybe should have posted here?

Got a good deal on this plane, NIB:

Graupner ASW-22 B270. Wingspan: 105", Wing area: 679 sq. in., Weight: 79 oz., Wingloading: 17 oz./sq. ft., Airfoil: Eppler 195 modified, Skill level: INT/INT, Radio: standard receiver, 4 micro servos, Motor type: 10-cell

Seems to be an older kit, with the following brushed recommendations:
Graupner Speed 700 turbo direct drive system, a 10-cell 1000 SCR battery pack, and FX35D speed control. Alternative is Turbo 900

NSP has an old posting with Sal offering:
Mega Midi 7 with 8 cells and a 10x6 Graupner prop & FX35D ESC.

Anone have a different opinion? I'm thinking I'd like to go the higher-voltate Lithium Polymer route, with high-turn DD brushless motor. While not new to electrics, this one is a LITTLE different from what I'm flying just now ... and I'd really like to follow a success story...

Presently I fly two electrics: a S480 powered TwinJet, on (9) RC 2400 cells, and an OD Su-27 Flanker on a Mega 16-15-5 and 4S1P LiPoly.
http://www.tnelson.rchomepage.com/vi...lageLipoly.wmv

#2 WarrenKriesel Sep 24, 2003 01:46 PM

Yup, I had this plane. It barely climbed on the recommended power system, but better with 10-cell CP1700. The 4 servos did not heat the ESC with BEC. A medium sized geared brushless setup would be best. You will notice ALOT of wing flex. Those two skinny wing joiners aren't strong enough. I lost mine while bringing it down from a big thermal, and the wings folded. I would recommend putting in flaps, so you can get braking action from the crow position. I can send instructions if you want. But then, you'll have to use a receiver pack. However, with the weight savings of switching from sp700 to brushless, the net weight change might be zero.

I had alot of fun flying it.

Warren

#3 WarrenKriesel Sep 24, 2003 01:51 PM

Oh yeah, that plastic battery holder will be toast on the the first hard landing. Just go ahead and wrap it with duct tape.

#4 WarrenKriesel Sep 24, 2003 07:09 PM

1 Attachment(s)
Launching method

#5 Thomas Nelson Sep 27, 2003 01:37 AM

Good stuff, Warren. Thank-you very much. Also sounds like you and I are on the same wavelength regarding the joiners and flaps. Nothing beats flaps at 90 degrees for glidepath control :D

How many watts do you think I should planning on? I WILL be going brushless, but was hoping to use a motor with mucho torque to eliminate the gearbox. And I was hoping to use 5 or even 6 LiPoly cells in series (6S1P), meaning high voltage and low amps. Perhaps 330 to 400 watts ... sound reasonable?

#6 WarrenKriesel Sep 28, 2003 08:53 PM

I would keep it pretty moderate because of the wing flex, like 60 watts/pound. This is a five pound plane. Good luck.

Did you want the flap instructions? They are for the MPX Kranich, and these planes are similar.

Warren

#7 Thomas Nelson Sep 29, 2003 06:20 PM

Please and thanks, Warren! I'll PM you with my e-mail addy for the Flap info.

My thoughts regarding power are starting to head in two directions. Feel free to comment:

1. Mega 7-turn (direct) with 6S1P 2100 Lipoly cells delivering some 15 amps. Would be around the 300 watt mark. I'd imagine the AUW would be around 3.5 pounds. Would need to play with * calc to estimate an appropriate prop. Obviously, with the 7-turn, I am aiming for a reasonably large folder. I'd wonder about the need for nose ballast, however. But this would result in a nice LIGHT plane.

2. Larger Mega, lower wind, and gearbox. Lower cell-count with higher amps. IOW, a more traditional setup with brushless power. In this case, I could easily get 400 watts or more, but I'd use the 9 cell RC2400 pack that I already have. Around 40 amps or so.

In both cases, the idea is to prop for good vertical, but at a slow speed - maybe 30 mph ish. Regardless of the power setup, I'd definitely not be yanking the bird around - just looking for suggicient power to get to thermal-chasing height quickly.

Thanks for your help with this one!

tn


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