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Extreme Flight Yak 55SP-E

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Regarding Extreme Flight's new electric Yak. Does anyone know the approximate size of the carrying case that this plane comes with? They advertise that it can be disassembled and put into a carrying case for easy transport.


ProBro #222
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Man I saw the one at Nashville, but was ooohing and ahhing over the plane. I'd guess about 36" X 12" X 2", but that's pretty rough guestimate.
Auger knows everything ! He even oohhh's and aahhh's :lol: :wink:
They are shipping right now..

Chris said he would call when they came in so I could pay for mine...but he ain't called. I guess we'll see if he really wants to sell me a plane or not.
I gotta say this is one of the coolest planes I've seen in a long time.
I've got a decent motor, gear box, and radio stuff. I'm waiting for the plane, and a battery. (LHS is getting me one of those 30 amp Kokams)

So Chuck, E-Flite 400-4200, CC P-25, and a 6.60:1 12x6 an a 30 amp Kokam 3S? I have an Electron and 4 HS-55s.

Is that workable for this one, or still not enough to get the job done?
I don't know much about the E Flight motors.. is this the long can job?? It'll be plenty of power. Not a huge Kokam fan...seems like those high capacity packs are heavy, heavier than a 2P pack of regular cells half as large. But either way, you'll have plenty of power.
The motor is a clone of the Himaxx 2025-4200.

The battery is a little more than an ounce heavier than the Tanics with the same discharce capacity.
I have been calling over there to EF for the last two weeks and can't get any answer.
I have the e- Yak on order and want to know about that big 87" Yak !!

Is there any Thread here or on RCU about the big Yak?
TailTwister said:
What's RCU?
Yea, I thought I might get something like that.
Sorry to be so predictable... :oops:

Anyway, Wayne Geffon works with Chris on most projects. Odds are, he has flown the plane. Drop him a PM, and see what he says.

I've seen vids of the plane (the prototype) with Chris at the sticks. It looked like it flew well.
Just got a call from Chris and my little Yak is payed for and shipping!!
I guess that makes you the guenie pig Chuck.

Though, I don't think that plane's going to do anything but ROCK!

Give us a flight report as soon as possible will ya?!
Yeah Chuck, beat the snot outta that thing, and let us know how much it liked it! :twisted:
I keep trying to get on the Extremeflight website and I keep getting a "bandwidth" problem message. :evil:
So Chuck, E-Flite 400-4200, CC P-25, and a 6.60:1 12x6 an a 30 amp Kokam 3S? I have an Electron and 4 HS-55s.
Man!!! I hope this mess is somehow standardized in the near future. :x All that mess might as well be Russian sweet talk. I can't figure it out. I got the 12x6 part and the HS-55 part, but the rest made me dizzy... :shock:
2FAST4U, I'm with you on that one. The electrics need to standardize.

I like the Himaxx way of identifying a motor. 2025-4200. That is a 20mm diameter motor, 25 wind, 4200 rpm per kv motor. If the last two zerso are numbers, ie 66, then it is a geared motor. A 2025-4266 would be the same motor with a 6.60:1 gear. I can get that, now that someone explained it.

E-Flite calls it a Parkflyer 400-4200. 4200kv number still makes sense, they use 400, as it replaces motors in a speed 400 class. The Parkflyer 370-4100 looks a lot like a Himaxx 2015-4100. 2015 is a smaller winding and shorter can.

The Hacker version is a B20L. 20mm I see, and "L" is long can indicating it is their longer version. The "S" is like the size of a 2015 or Parkflyer 370. The Hackers out power them well, due to the QC, I guess.

Extreme Flight uses a designation like Hacker.

Great Planes just goes by replacement type, ie 400, 500, 600. Except the Ammo 20-4300, which is almost like Himaxx minus the winding.

Then, there's the fuckin' outrunners, and nobody knows what the hell any of that shit means!
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oh outrunners are easy!

axi 2814-12 28mm can, 14mm long (im assuming this is the length of the magnets, or the thickness of the stators, not the actual can), 12 turn winding.

2808-34? 28mmwide, 8mm long 34 turns! the more turns, the lower the Kv and the higher the Kt. (that means fewer rpms and more torque)

im assuming lehner has a *similar* type (dia/length-turns) but with different measurements specified (magnet size?)

the Mega aCn's also use a similar 6 digit representation, although I admit the Kv on the himax's is nice, it dont say much about the power rating for the motor.

personally, I look for a motor's max power in watts, max # of cells (or voltage), and its Kv. Kv and max V will give you an idea of motor RPM, and whether you will gear it or not (anything that would give over, say, 9k rpm would do well geared, in the case of all-out thrust) and max power will give you an idea of the prop you'll use.

for example: axi 2814/12 has a kv of like 1020 or something like that, and max is somewhere around 10 cells, so 3s pack would kick out something like 11000rpm at best. I know from experience that 350 watts at 11k rpm is somewhere around a 9x6 to an 11x4 prop. it would be kick-ass to plot a graph of the power needed to turn a prop at a certain rpm.

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