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Old Feb 22, 2002, 07:59 PM
I am M I G H T Y !
Steve Wrona's Avatar
Ipswich, England
Joined Feb 2001
486 Posts
Gas/Petrol engine = ? E-Motor ?

I've had my eye on the beautifully designed Matney's Models "Rivets" Quarter Midget Racer as a first Wet to Electric conversion. I have been pondering a question that, no doubt, a few e-flyers have had and ,hopefully, more have figured out:
Is a geared 280 comparable to a .049? Is a S400 equal to a .15 or .25? Is there a chart available comparing motor capabilities to engine capabilities?

I thanketh thou,

Steve "Wha?" Wrona
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Old Feb 22, 2002, 08:56 PM
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epilot's Avatar
Germany, NDS, WOB
Joined Nov 2000
5,953 Posts
Just look at the power output. One BHP is app. 750 watts. Many IC engine mfgs state output in BHP.

There is more to it though. Electric motors are more easily geared and can use larger, more efficient props.

What I like best about electric is that you can test fly an unfinished model - no oil dirty up the airframe.

Michael
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Old Feb 22, 2002, 09:11 PM
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Steve McBride's Avatar
Agra, Oklahoma
Joined Feb 2000
5,390 Posts
IN all actuality - if it were strictly a question of "what motor equals what glow engine" the answer would not make you happy. I would estimate an .049 power output to a good 500-600 class cobalt, but as epilotmentions, there is more to it that that.

IE - I would not hesitate to put a planetary geared 400 in place of an .049 in a large glider type airframe. You will get better performance.

But put an 400 direct drive in place of an .049 on a somewhat heafty or draggy model and you probably will be a bit disapointed.

For an .049 racer type to electric, I would consider a P450 or Graupner 480 as a good start. Again, this is not always the case. I'm not familiar with the airframe you speaketh of. Perhaps you could get by with a 400. I know some of the HOB .049 models fly fine (although not spectacular) on Speed 400.

I know, very vague. I suppose if supplied with the weight, WS, area, etc. the true gurus of the Ezone (which I am not) could give you a list of great drop in suggestions.

Good luck on the project. Keep us informed of the progress.

Steve
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Old Feb 22, 2002, 10:51 PM
Master of the Wind
AIR MOVER's Avatar
TEXAS
Joined Jun 2001
3,044 Posts
what is the motor used on the wet version of this racer does it say 049 to 15 or such? anyhow that plane with a electric set up is going tobe with out question heaver...eeeek i said the fat word... anyways.. the power to weight of a 049 vs a speed 400 on say 7 600s just wont match .. yes i geared 049 motors and wow wow. uh huh uh huh in fact not to many years back someone of a major hobby co. sold geared 049s for there gliders. ahh nice little set up but with lil insight you can make your own gear box... the racer type plane you have is made for speed.. its a scale looking model so anything at a nice pace should keep you happy as your flying this one for the looks.. more so.. a direct drive 6v speed 400 on 6 600mah will be a fine start. but if you want the same speed and yet the same wingloading as its gas counter part you would have to spend the bucks and buy a astro 010 on 7 350mah nicads.. there your weight to ratio would be as close as you get since you dont have to gas proff the plane you can save alittle weight here there less vibration from electrics so you can mod the kit a tad as far as making it lighter at its finished weight...all done n said the electric version would be close in ready to fly weight as the fueled up gas proof plane .. or... or.. buy a speed 300 cheaper motor and run 6 350mah nicads and be near the same goal.. i would love to see a micro nitro burner geared flying indoor.. with a half oz fuel tank.. on a .0050 size engine.. such a motor of this size would hardly make a mess let alone sound loud.. half oz of fuel say with a 8 min burn time a full throttle would be a wonderful thing.. gee maybe a .0010 engine with a unloaded rpm of 40k ... wag wag micro jet slurp.. all up weight 2oz ready to fly wag wag wag wag slurp drool drip tell the people in the gym that the tiny puff of smoke is too help ward off and small flying insects.. smirk
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Old Feb 22, 2002, 11:18 PM
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Ralph A. D'Amelio's Avatar
United States, MA, Chelmsford
Joined Jul 2000
3,444 Posts
Thats a tough one..always wanted something like that when I started in electric since I been doing ic for over 25 years. My approach is see works for others in comparable airplanes. Example, my 120% TM with a 5:1 geared 300 is just great. nice realistic speed and with plenty of power on a 8/6 prop. The HL spit with a 480 isn't all bad either. A MM motor with a great planes gb will pull a 3lb airplane easily....like the other said to many variables.
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Old Feb 22, 2002, 11:55 PM
Registered User
N.B. Canada
Joined Nov 2001
102 Posts
Craig Kulesa has a page that gives a comparison of glow to electric, dealing mostly with Astro Cobalt.
http://loke.as.arizona.edu/~ckulesa/propulsion.html
It's a fairly detailed chart on prop/battrey/runtimes for the electrics and compares Direct drive to 2-strokes and geared to 4-strokes.
Maybe a more experienced electric (former IC) flyer gould look and their opinion on these.
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