Just about any pattern plane can be converted to electric. I would look for
one of the built up models so you can control the weight a little better.
Power for this kind of plane will be VERY expensive, in the $1000 range.
I am a newbie at electric, but I am interested enough, after having
purchased a few low power electrics, to look into buying a muscle bound
propulsion set up for my Great Planes Fun One (5.5 lbs.). I want the model
to be powered as well as it would be with my Webra .50 onboard, but lighter,
Any hints? TIA
To get lighter and have as much power is a real challenge Ed.
The good news is that Lithium batteries and probably a good 600W plus
outrunner would be a good match for the airframe.
here are some possible motors for you - you will probably have to
reconstitute the URL if your reader wraps lines.
You would need something like a 6s LIPO pack capable of 45A or better.
Much better to pop over to the Ezone (RCGROUPS) and ask there though.
I'm in the process of converting a .46 size Great Planes U Can Do 3d
which will be in the 5.5 - 6 lb range ready to fly.
Here is what I bought for the conversion
You can vary the price a little with your choice of brands but not
1 Axi 4120/18 Outrunner motor 11.7 oz 146.73
1 Jeti Advance 7-3P OPTO ESC 2 oz 128.27
1 Ultimate BEC 1 oz 34.90
1 Radial Mount set & prop adapter 1 oz 28.90
5 2 cell 1500 ma LiPoly packs @ 31.20 2.8 oz 156.00
5 3 cell 1500 ma LiPoly packs @ 45.50 4.0 oz 227.50
Total weight of 49.7 oz
My Enya .80 24 oz
500 ma flight pack 4 oz
12 oz fuel approx 10 oz
Total weight of glow power system approx 38 oz at take off
A total investment of 722.30 in power system. I'm sure there will be
some misc items such as connectors , switches etc that will probably
run 50.00 bucks or so and of course some asstd props at 5-6 bucks
I planned on a 5s5p battery configuration which will give me 18.5
volts and 7500 mah. May be a little more than I need so I'm going with
a 3s3p first to see how that does....which will also lighten my system
13.6 oz for a total of 36 oz which puts me in the range of a glow
I'm not sure how much the weight difference between 3s3p and 5s5p
will affect flight duration and performance but I suppose I will find
It's not cheap but I think it will be worth it. Although I still fly
glow , I 've been flying electrics very actively for about 4 years now
but these have all been small , lightweight aicraft in the
1-2 lb range.
Looking forward to trying out the U Can Do. :-)
I see that my Charter cable system is on the blink, which would explain why
my response, made many, many hours ago, never made it to the newsgroup. This
is why I maintain one of the ultra cheap dial-up providers - "Just In Case".
What does 5s5p mean? It looks like 5 in series with 5 in parallel? I doubt
I used to fly a little competition fun fly, so a flight duration of 5
minutes would be plenty for me.
How long does it take to charge the Li-Poly packs? If you want to fly the
way you would with a glow powered plane, can you do it with a field charger?
Or do you need to have multiple packs pre-charged?
Why did you choose that particular motor? I'm curious. I would like to learn
some of the logic that you employed, even if it was cost based.
That's a lot of questions. I'm sorry if I have loaded you down with too
much. Thanks for jumping in there and providing some useful information.
It takes over an hour to fuylly recahrge packs, but if you run tehm
conservaticely (advised for decent life on teh v expensive packs) you
should get 3 5 minute flights between full recharges, and maybe a 20
minute charge time aftre a single flight. I find with take off and
landing and some low throttle flying, it takes me about twice as long to
recharge as the total length of flight - i.e. all of it from walking out
with te planbe, checking out, takeoff/alnding and retrieval etc.
I can get aanuthing from 15 minute sto 490 minurtes out of one charge as
well, which often means I simply don't bother to field charge at all.
Its a very good replacement for a 40 sized glo - similar power/RPM curve
to a decent 4-stroke ands turns similar sized props without needing a
gearbox. Its not horrendously exensive.
PACKS are almost more important than motors you will find. The batteries
are what proiduces the power. The motor is just a small part of the
overall power train.
I have a total of 10 packs....five 2 cell and five 3 cell 1500 ma.
I wired one 2 and one 3 cell in series to get 18.5 volts.
Then I wired those five in parallel to get 7500 ma.
I think I will change it to 5s3p after talking to some electric flyers
who are getting 10-12 minutes aggressive flying with this
configuration in the same weight 3d type aircraft.
I think I will change it to 5s3p (18.5 v 4500 ma) after talking to
some electric flyers who are getting 10-12 minutes aggressive flying
with this configuration in the same weight 3d type aircraft. It should
do (on paper) 6.75 min at full throttle.
I can charge all the packs in one hour on my Astro Flight 109 D. It
has a max charge rate of 8 amps and it will actually do that. I have a
parallel charging module that I picked up at Hobby Lobby.You can plug
up to 5 packs into it. It was cheaper than buying enough Deans
connectors to make my own and very convenient.
Actually , it wasn't cost based. As you can see I spent a few bucks ,
so I wasn't going to let a few dollars more ruin my experience.
I chose that particular motor because:
(1) I like outrunners.I have other smaller ones and I really like
them. No gearboxes. Very smooth , quite power.
(2) It will handle the voltage and amperage to get the total watts I
need .18.5v x 40 amp = 740 watts which gives me approx 125 watts per
pound which will give me the performance I want.
(3) I have seen many electric conversion articles where they used the
same motor with excellent results.
(5) and most important.....it's real "pretty"....and sexy , in that
black and gold case. :-)...add a shiny prop adapter...Mmmm...mm.
Ed , almost forgot. As "Natural" said in one his posts , the most
important part are the batteries. Thats really where you start when
you are deciding on a power system.
First figure how many watts per pound you need , how many minutes
flying time and that will determine the batteries you need. Then find
a motor and speed control to handle them. I may be oversimplifying
things a bit , but thats the basic process.
Unlike glow , electric motors have a wide power range depending on
what you feed them and how you prop them. Thats why it's hard to
compare to a glow engine.
Yep. 5 series and 5 parallel.
Most packs safely charge at 1C. Some can tolerate 2C. That means you will
spend a little over one hour for a complete charge at 1C and a little over
1/2 hour at 2C. At least this is my experience with my Multiplex charger.
It charges at the set current until the battery is about 90% charged then
the current drops off quite a bit to top it off.
I am also looking at the electric scene. I think that right now, a .32 size
plane is about optimum for performance electrics without going overboard on
cost. I am designing one with some unique design features. Shoule be very
light. I am also testing some batteries I got from a supplier overseas.
On Sun, 22 May 2005 23:13:09 +0100, "Paul McIntosh"
Paul , I know you addressed Ed but I would like to say that it would
be expensive , but not quite in the multi thousands. Pattern flyers
are using electric more and more and getting long flight times without
a leg and arm investment.
I'm not sure why you would need 2100 watts for 15 minutes since no one
flys the whole pattern at full throttle. We're talking a15 lb airplane
when we get into that much wattage.
Here's an approximate estimate of what it would cost ...mind you , I
said approximate since I'm certainly no authority on electric models.
1 Motor and speed control approx 400.00
4 Thunder Power 5s4p 6,400 ma packs @339.00 1356.00
Misc connectors adapters etc 50.00
Wire these in a 10s8p configuration and you will get 37 volts and
12,800 ma. 37 volts @ 55 amps will give you approx 2035 watts.
This will equate to about 14 minutes of flight time at full throttle.
Actually you won't need this much battery but I'm just trying to get
at your figure of 2100 watts for 15 minutes.
I don't know how to figure what percentage of throttle to use in
pattern flying , but someone here probably does.
Someone please correct me if I'm wrong.
The handwriting is on the wall. It won't be too many more months/years
before electric power dominates pattern. It is kind of sad in a way. It will
mark the end of an era. Then again, I see the same thing coming for
Once the price of batteries drops to about a 1/5th of current prices, glow
flying will be strictly for the sake of nostalgia.
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