What I'm talking about
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.
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.
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