[ChuckAuger]

While I own a couple of Axi motors, I'm less than impressed by their performance. You gotta love the poor little 2212/34, it has been packed in a thousand times (not exaggerating) and still runs.

But when trying to establish a viable power system for 3D planes, I came to the realization that something was wrong, the Axi just don't do very well.

Now don't get me wrong. If you are looking for a quite motor without a gearbox, a motor that will take 1K crashes, and are not worried about performance, the Axi is a fine choice.

But Axi has been developing new motors, and have finally come up with a motor that turns pretty close to the same RPM as the motor I'm running on my E Tacos, on the same prop.

This motor is the 2826/10. It will swing a 14X7E at 6930RPM (at 5200 ASL). This is very close to what the Lehner 1020/15 at 6:1 turns the 14X7E at 3250ASL. So we have a good comparison!

Post from RCGroups:

Static tested the 14x7E prop tonight on the AXI2826/10. Used my 4400 Irate 3S2P pack instead of the 5200 pack. Here are the results :

Altitude 5200 feet ASL.

APC 14x7E
A 41
V 10
W 410
RPM 6930 (ThrustHP estimates 88oz of thrust, 46mph pitch speed) .

This is great news. Finally a viable equivalent to the Lehner 1020/15-Cobri rig. Except...

This Axi weighs 6.4oz without the radial mount. So 7+ oz for the motor and mount. The Lehner/Cobri combo weighs 3.5 oz with the collet prop adapter. But hey, weight is not everything. Although 3.5oz extra hanging on the nose of a 25 oz plane might seem like a good amount, it's really only 14% of the AUW.

So let's look at performance.

The guy above was drawing 41 A to spin the 14X7E. He was running (2) 3S 2200 packs to make a 3S2P 4400. This pack will weigh right at 10 oz.

The Lehner 1020/15 draws 30A to generate 6500 RPM, so slightly lower RPM, but 11A less. This means I can run a single 3S 2500 Tanic, 6 oz. So I draw 73% as much current to get almost equal RPM ( I am 2000 ft lower)

So now we have 3.5oz less motor, 4oz less battery. 7.5oz off a 25oz plane is 30% lighter (but the plane will weigh more, so...). Or, my plane weighs 25 oz, an equivalent Axi powered plane would weigh 32.5oz, similarly equipted.....77%as much for my plane (To put this in context, it would be the equivalent difference between a 4.5lb profile and a 6lb profile)

So this is where all the misunderstanding about me and the Axi comes into play. To me a 23% ligter plane that draws 27% less current is a good deal. But some guys do not care about the weight or the current, and for them the Axi is a fine choice.

Please don't let me talk you out of the Axi, if that is what you want, by all means buy it! Please! Just understand why, if I seem to be less than enthusiastic about them, this is the reason. There are LOTS of happy Axi users out there, it's just that I can't run the numbers and be as enthusiastic as they are, that's all.

 

[mfeuilly]

Hi Chuck, me again. I agree that the Lehner Kicks ass, but the AXIs are OK. They are budget motors, even for outrunners. There are some $$ outrunners that would be more of a comparison to the Lehner as far as quality of motor, but I can't afford them(or a Lehner). I don't have the 2826, but I really like my 2808/24. I'm proped way higher than recomended, and the Hobby Lobby sites says 37oz of thrust with the recomended prop. I would guess I'm well into 40oz of thrust, judging from how it flys my 20oz plane. I get 17 minute flight times, and I could get well over 20 if I held back. This set up is on my Attitude, which used to use a direct drive mega as the recomeded power plant. The AXI weighs the same as the DD Mega, but gives better thrust for less amps. Todd now recomends a geared mega and even had a custom gear box made that he's going to sell. The AXI is lighter than the geared mega, but has less thrust, and probably more current/oz of thrust.

I'm begining to think outrunners are best for smaller planes, when doing 3D. My cdroms do great on my little bipes. My current one weighs 4 1/8oz, and has 11oz of thrust. Thats around the same power to weight my Attitude has, on a stator that was designed to run at a fraction of the current I'm using. The 2208 AXI appears to fly the Hell Raiser great. I think the 2212 could be pushed harder than I have seen anyone push it yet, but I haven't tested that theory yet.

damn... I'm babling aint I

 

[cropdusterdave]

chuck, where do you find the lehner? I've looked all over and only find a couple of the bigger one for cars. I"m planning an E Taco this winter.

 

[ChuckAuger]

Well, I push the 2212/34 harder than about anybody. I've ruined 4 Etec 1200 packs with it. But that's not what I was trying to get across.

I know Axis are fine choices, you are a perfect example. You like it fine, and that is all that matters. That was all I was trying to get across.

I am building some fairly niche planes, and guys say "I want a plane just like Chuck's". All I was trying to point out was, if you saddle it with a different power plant, it won't be the "same". It ain't gonna be "just like Chuck's". It will be a great plane if that's what you like, but face it...the 25 +/-% difference will significantly affect the performance.

I'm in no way saying my way is the only way, it is just my way. That's why we have "my way" and "your way". Your way will yield a fine plane, but I'm trying to keep people from confusing that with my way.

The last 2 paragraphs in my previous post attempted to explain my position, obviously not very well.

 

[mfeuilly]

probably explained it just fine. I shouldn't post stuff that late at night(early morning.)

I'm relatively easy to please. If it goes faster vertical than what I like to cruise at, I'm happy. Not that I complain if it goes a lot faster :twisted:

PS you know how much you were pulling on the 2212? I was thinking of putting a 12x8HD on mine. SF props suck on outruners.

 

[birdie_in_texas]

try troy at bishop for lehners..

www.b-p-p.com