cygnet

My Feedback: (33)

Hi all I just got an original Taurus kit I'm thinking to building it in a electric version has anyone done this? I have a long histiory with the taurus as it was my first pattern plane and I loged over 1000 flights on the airframe, I don't own any glo motors anymore(all gas and electric) but I think electric would work well. Any thoughts would be appreciated.

Free Bird

Perhaps King Altair will chime in, I believe he e-powered the Primus, which is a modern version of the Taurus. Nice find on the Taurus kit!

FB

UStik

An electric Taurus must be great! I think the modern electric drives are in some respect similar to the old glow drives. If you have the same power, the electric drive will weigh about the same. It is even better because it saves the hassles (I think you know that better) and gives a better flight behavior (because an electric motor matches a propeller better than a glow engine).

From calculations made for other models a while ago I might suggest two example drives:

AXI 4120/14 motor, suitable 40A ESC, 6000mAh 5s2p LiPo battery, 12x8" APC propeller.
Weighs 44oz, runs 10+ minutes. A bit heavy, but ballistic for a Taurus.

AXI 4120/12 motor, suitable 30A ESC, 6000mAh 4s2p LiPo battery, 12x8" APC propeller.
Weighs 38 oz, runs 15+ minutes. Still quite heavy, but maybe better for a Taurus.

The configuration could be fine-tuned (e.g. using A123) spending some work on it.

Just my thoughts...

cygnet

My Feedback: (33)

Good suggestions I'm not to worried about the weight as I recall we flew the taurus in the 6.5lb range and it handled very well I think it would do fine at 7.5lbs. I flew mine mostly with a piped 60 way over powered I also used a piped YS 45 which in my opion was the best power plant so electric that can swing a 12x9 say at 10-11K would work out very nice. I do have about 100 1100 mah A123"s looking for a home, they might just be the ticket I could charge right in the plane.

pd1

I have an electric Taurus.
The only problem is the reduced flight time.
I'd stuff as many A 123's in there as I could.

cygnet

My Feedback: (33)

Great I need details motor,prop,batteries,amp draw,prop RPM oh and all up weight

pd1

I cheated on that one. It's only a 70% Taurus. 50 inch wing.
All up weight only two pounds.

I have a couple E-Flite 60's that I've been using in 7 to 8 pound planes.
I'm building an Aeromaster for one next.
The E-Flite draws 55 Amps with a 15x10 prop on 6 cells.
It only an opinion, but I think the electric motor has more pull than the glow engine.
I have a Trainermaster with an E-Flite 25 that goes absolutely vertical until out of sight.
I never had that performance with a 40.

UStik

Well, not only an opinion, usual electric has more pull than usual glow. The first drive above spins at 10-11k rpm, the second 8-9k. These are outrunner motors, and the inrunners are often geared. The propellers are a bit bigger and have more pitch than the usual glow propellers. Prop efficiency is much better so the drive pulls more than a glow drive. Think of the long-strokes (like a Hanno) giving less hp at less than 10k rpm but still pulling better with a 12x11 prop instead of a 11x8 on a short stroke. You may use an ungeared inrunner at high rpm, but efficiency would be bad so you'd have only 3 minutes flight time. Electric is better also because the torque increases proportional to a rpm decrease.

Just use [link=http://www.drivecalc.de/]Drive Calculator[/link] to fiddle with the drive components. I'd stick to the slower-flying, longer-running drives, though. Taurus is an elegant slow-flying plane, not a rocket. A 12" prop should be no problem, 13" or even 14" should be possible on paved runways. May look weird but pulls nicely and gives good flight times. You might have to get used to the prop torque, though. But that's all just me.

And yes, I as well think the A123 cells are better than conventional LiPo. Not only charging in the plane, also very fast charging so you have more flights. And you don't lose time for safety measures. A benefit of the small cells might be that you can distribute them in the fuselage to adjust the c/g.

UStik

Sorry, double post.

Erik van Schaik

Definately go LiFePo. You can fly all year long if you want.

Have a look at this 16000rpm/10x4 combo:
YouTube - Winter A123

Currently I made an upgrade for a Sig Wonder at 9S A123 and 700kV/200gr outrunner : 17000rpm,30A, 79dB.
Yes this is as loud as 2-stroke, but the low pitch gives >2kg thrust as like on steriods with a great sport speed. The low pitch allows the good thrust at low speed too AND it is a great brake.
In the back of my mind I am reconsidering building a Curare40 with this setup. Best thing of all, I can use my 1200W charger for 5-6 minutes recharge time!

grtz! Erik

btw, feel free to ask info if needed!

Free Bird

Nice project! Just need a dummy engine up front to comlete the look!

BTW - did you modify the construction for the smaller size? Could you provide some details?

FB

pd1

Here's a build thread I did on the Mini Taurus.

http://www.wattflyer.com/forums/showthread.php?t=19864

I'd be happy to answer any questions, if I can do so without hijacking the thread.
Paul

Free Bird

Kewl! Thanks for the link, I'll check it out!

If I have any questions, I'll post them in the build thread.

FB