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Old Jun 01, 2007, 07:05 AM
Mt. Dora, Florida
mtdoramike's Avatar
USA, FL, Mt Dora
Joined Dec 2006
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Help!
Hobbico Avistar from Fuel to electric convert.............

I was given a Hobbico Avistar by a club member who crashed it upon take off. The only damage was to the engine firewall, which I repaired in about 5 minutes. He said he doesn't repair them. I asked him if he wanted the plane back because I'm not into glow, but he said the only thing he wanted back was the .40 sized engine.

My situation is, how would I convert the Avistar over to electric? I'm a newb with just a few flights under my belt with an instructor. I'm not sure how it could be done because the plane is a tad heavy even without a motor or battery setup. Right now, I'm using a Hobbico Superstar EP stock setup that I fly for training purposes.

Thanks for any insight,
Mike
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Old Jun 01, 2007, 07:25 PM
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I flew one with a Jeti Phasor 30/3 on 3s with a 40 esc. Originally had a 10 cell nimh pack, the I flew it on a 3s4p Thunder Power Gen 1 pack.

Typically at our field, the guys are running 400-500 watts with either a 3s or 4s pack.

One of many combo would be a E-flight power 46 running on a 4s 3700 lipo pack. A Castle Creations Phoenix 45 or better yet a Phoenix 60 would work great. Use either a receiver pack or a ubec to power the radio.

John
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Old Jun 01, 2007, 08:31 PM
Deletedfor proving Nauga wrong
Joined Mar 2005
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Essentially... get the power package thats in the ElectriStar.

Or.. get the Electristar instead of the Avistar....
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Old Jun 02, 2007, 06:15 AM
Mt. Dora, Florida
mtdoramike's Avatar
USA, FL, Mt Dora
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Quote:
Originally Posted by fhhuber506771
Essentially... get the power package thats in the ElectriStar.

Or.. get the Electristar instead of the Avistar....
I already have the Avistar!
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Old Jun 02, 2007, 08:10 AM
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I used an Axi 2826-12 and it flew as my trainer with a Thunderpower 3s 11.1 volt 4200 lipo pack and a jeti 40 ESC.
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Old Jun 02, 2007, 11:29 AM
know it all
Miami, Fl
Joined Nov 2003
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use this motor:

http://www.bphobbies.com/view.asp?id...27&pid=V736362

this esc:

http://www.bphobbies.com/view.asp?id...3&pid=A3237681

For $75 you have both the esc and motor.. I have the motor and it is very good, similar power to a 46-50 glow engine.

You will need a 4s lipo pack, I like the Dewalt A123 lipo cells.. they can be fast charged in 15 minutes and are very inexpensive.
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Old Jun 03, 2007, 06:58 AM
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Antioch,CA,USA
Joined Dec 1999
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Herms recommendations are exactly what came to my mind when I saw this thread.

The DeWalt packs come with 10 cells for ~$100 on Ebay. This'll give you either 2 5 cell packs (=~4S Lipo) or a 4600 5S2P A123 pack.
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Old Jun 03, 2007, 10:44 AM
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The main thing is keep the motor system light, as the airframe is overbuilt for electric use. That's why I'd look in the direction of lipos for this one. To keep it cheap, how about paralleling a couple of cheap 3s 2100 lipos.

John
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Old Jun 04, 2007, 12:05 AM
know it all
Miami, Fl
Joined Nov 2003
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people have been flying these planes with 32oz worth of nimh or nicad cells for many years.. a 5s1p dewalt pack is 12.5 oz, about the same weight as a tank with 12oz of glow fuel

As a matter of fact you are are replacing a 17oz 40 size glow engine with an 8oz electric motor, if you are not careful you may end up with a lighter plane, or a plane that will not balance.

I dont like regular lipos, they are expensive and delicate, plus you can only discharge them 80% .. you also have to wait for them to cool off before recharging, and they take over an hour to recharge.. the opposite is true of the A123 cells, plus they can be recharged in 15 minutes at 10amps.. I routinely charge my A123 cells at 15 amps in about 10 minutes, 15 if they are fully discharged

check the weight on this glow engine:
http://www.horizonhobby.com/Products...rodID=EVOE0400
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Old Jun 04, 2007, 01:35 AM
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All true, but IMHO it flies better with less weight. This might be better for a new pilot. Both systems will work fine.

John
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Old Jun 04, 2007, 03:51 AM
Deletedfor proving Nauga wrong
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cheapbatterypacks.com has some good 10C rated 4000 mah 2S Lipos at a very good price. A pair of those in series would be ideal. (they have 4S also... but the 2S gives more flexibility for other uses of the same packs.)

EXACTLY correct packs for the Electristar. (remember... the Avistar is same size, virtually the same weight, same speed range... So, identical power is appropriate)
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Old Jun 04, 2007, 06:56 AM
know it all
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I am sure that is true, but we are talking about 2 oz difference?, total plane weight of 90oz .. the os 40LA glow engine they recommend for this plane is a measured 400watt or less engine.

Quote:
Originally Posted by jonnyjetprop
All true, but IMHO it flies better with less weight. This might be better for a new pilot. Both systems will work fine.

John
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Old Jun 04, 2007, 11:22 AM
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Sometimes, that 2 oz will make a huge difference in performance.

For a pylon racer, every ounce you add means lost speed.
For an aerobatic airplane every ounce means you need to have more speed to do a maneuver, and you need more power to maintain the speed.
Just taking off... every ounce means more runway is needed, and reduced climb rate.

Usually, on a 4 lb plane 1 or 2 oz isn't noticeable, but sometimes its just enough too much to be really annoying.
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Old Jun 04, 2007, 03:43 PM
Got shenpa?
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2 oz on top of 90 oz...that's about a 2.22 percent increase in weight. A mere 1% drop in the battery voltage will cause a similar change in power/weight ratio. All of us who fly electric experience much more change than that during every flight as the batteries lose their charge.

Heck, a change in the air temperature will cause greater changes in flight quality than this. So will a change in altitude, a change in humidity, a change in motor temperature (wire resistance goes up as it gets hot), or normal aging of the battery pack as it gets more cycles on it. I don't think most of us RC pilots worry too much before a flight if the air temperature has gone up a few degrees since our last flight (though pilots of full-size aircraft certainly do pay attention to altitude, air temperature, etc - they have to, they don't have the vast excess of power most of our models do!).

There are certainly RC models where you will notice 2 oz (any small 3D plane or GWS foamy, for instance). But, with all due respect, I am extremely skeptical that 2 oz will matter a rodents behind on a nearly 6 lb trainer. That's less than the weight of most receiver packs!

-Flieslikeabeagle
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Old Jun 04, 2007, 03:45 PM
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Quote:
Originally Posted by hermperez
Anyone know if this motor is reversible? Edit: I meant to ask if the motor shaft is reversible. Sorry for the poor choice of words. I couldn't tell from the BP Hobbies website, and a few RC Groups searches didn't turn up anything useful either.

TIA,

-Flieslikeabeagle
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Last edited by flieslikeabeagl; Jun 04, 2007 at 09:41 PM.
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