ghost123uk

Hi all

I know very little about E-Power.

I own 2 x Herr Little Extra as seen at =

http://www2.towerhobbies.com/cgi-bin...&I=LXFWM2&P=RF

basically =
Low wing aerobatic sportster
Wingspan: 36.5
Weight: 18 - 22 oz
Wing Area: 344 sq in
Designed with the Novell 074 in mind

I fly one with a Thunder Tiger 10 installed and it is very nice to fly.
The other one is yet to be assembled, and I would like to fit Electric Power

Question = What E-Power motor would I be looking for to get similar, or slightly more, performance ?

The only proviso is I would prefer to use Sony US18650GR Lithium Ion cells, as I can get plenty of these from work.
At present I also fly an E-Power trainer with a geared 380 on a 9 x 6 APC E-Power prop and 2 of these cells in series give me about 15 mins engine run.
I mention this to give some idea of their capacity.
Note - I am ok at wiring cells in various parallel and series configurations as required.

KidEpoxy

Do you know how many amps those cells can put out before heating up?

ghost123uk

No not really

All I can say is, according to a quick search they are 1800 mAH each, and after a 15 min run on my geared 380 with APC E-Power 9x6, they are only slightly warm.

Not sure if that is any help.

I do like them in my trainer set-up, as a 2s / 2p setup gives my 30 min runs with a wieght that is no problem

If I have to go to LiPo, then I will, just trying to save money !!

KidEpoxy

I may not have looked hard enough, but I found 2 places that say they are a 2C discharge, so ~3amps..... that is a tough nut to crack when looking to get some real power out. Even in 2S2P, ~7amps aint many watts of power, and 3s2p is startin go get bulky.

Dunno, but that 2C discharge might be a dealbreaker. You are gonna have to consider a motor/gear/prop that is easy on the amps

I've been out of electrics for a year or 2... but I'm sure somebody can help with your limitted amps situation.

ghost123uk

Ummm - if that is the case, anyone else replying to this question might like to assume that I will have to go with buying LiPo's

edit = I am interested to check the discharge current on my current set-up when I get home...

Bipe Flyer

E-Flite makes a Power 10 Brushless that is supposed to be a direct replacement for a .10 engine. I've only seen their smaller motors, but they seem to be quite good.
http://www.horizonhobby.com/Products...odID=EFLM4010A

An AXI 2814/12 or 2820/12 should be about right. I've flow a plane with the 2820/12 and it is has lots of power.
http://www.hobby-lobby.com/brushless-axi2814.htm
http://www.hobby-lobby.com/brushless-axi2820.htm

These are outrunner motors, so they use larger props, in the 9" to 12" range.

If you want to run a smaller prop, more like a .10 would use, then a Mega Motor 16/15/5 would be a good choice. It does very nicely on a 7X3 prop on 3 to 4 cell LiPos.

Make sure that your battery packs can supply 30A continuous for all of these motors.

ghost123uk

Thanks for that last reply - good info there

Question = are there disadvantages in using 9 and 10 inch props on a failrly small aerobatic job as outlined in the first post ?

Might I be better to go for a motor designed for 7" props ?

KidEpoxy

The suggested motors are looking at 250-350watt ballpark using around 30amps
them cells you have just aint in that neighborhood of output, they are duration cells, not burst output.

ghost123uk

Aye cheers for that KidEpoxy - your previous info has taught me that.
I am resigned to buying LiPos to go with whichever motor I finish up with.

Still wondering if I should be looking at a motor designed for 7" props (rather than the type that need much bigger ones) ?

Any chance anyone could do a short begginers guide re :-

Outrunner motors ?
Gearbox V No Gearbox ?
Brushed V Brushless ?

combatpigg

My Feedback: (3)

Go with more prop diameter if it can be turned effectively with the same weight package as the equivalent glow set up. This is what gives small electric planes a huge advantage over glow for spectacular aerobatic capability. Go with as much diameter and as low a pitch as your power package is rated for, and explore the flight envelope that small glow flyers can only dream about.

Bipe Flyer

Larger props are more efficient and will provide more thrust. The mega motor is no slouch though. Check out this video clip of a Jr. Falcon with a Mega Motor 16/15/5 and a 7X3 prop. [link=http://www.missionwings.com/videos/JR%20Falcon.wmv]JR Falcon[/link]

Because an Outrunners spin larger props, they are replacing gearboxes.

flyinrog

My Feedback: (1)

There was an article in FlyRC ,they took 2 of the Herr extras back when the were a hotter item,,did one up with the Norvel .074 and the other electric..I doubt I still have the Mag but if I find it I will post the setup they used I am certain it was with Lipo's though..the .074 I put in mine didnt have the power (bought it used) left in it to fly mine...I am in the process of rebuilding it and have a Magnum XL .15 ready to mount up to it..that should be able to take off in 10 feet or so I hope...will check after the holiday week is up....Rog

ghost123uk

Hi Rog - yep the original post mentioned at the top of here, concluded that a 15 was a better bet.

I am likely to be buying a motor / LiPo packs from eBay ( to save money ) and am hoping to finish up with somthing that gives a good 10 towards a 15 type power.

So, from what I have learned on here, it looks like I should be looking for an outrunner motor, around 350 watt and a PACK and ESC that can provide 30 amps, and use a 9 or 10 inch x 5ish prop.

Does this sound about right ?

JB

ghost123uk

Anyone got any comments as to if this would be suitable = http://tinyurl.com/nqted

I note it is only rated a 18 amps but the thrust is quoted a 1Kg ?