Motors

What would be the noticeable difference having 1100kv motors compared to 880kv motors on a quad?

What are the pros and cons for higher or lower Kv motors?

Would I be correct to assume if I put one different Kv motor on one arm from the other three motors that the AMP would compensate to keep it flyable? Has anyone tried this?

If that's the case then it would also work if we had one different ESC as well right?

I'm now building a small quad just for the purpose of test flights and testing systems etc and will give this a try at some stage.

Replies

• Developer

This is a fantastic tutorial on sizing a home-made quad.

It needs to go in the wiki!!

Anyone know how to do that?

• In a multi is recommended that all engines are equal and the esc too.
Coaxial only can play with different engine rpm

• Then an engine deal 70% efficiency weighing 7.75oz above. (219 grams) with a kv of632.
And at 80% efficiency weighing 6.77oz (193 grams), with 557 kV.

An engine with 80% efficiency should bear. 576Watts minimum.
An engine with 70% efficiency should bear. A minimum of 659 Watts.

To do the same job.
There is clearly a disadvantage to use a little engine efficiency.

When selecting the motor within the range observed. The most appropriate, will be thelighter weight and greater efficiency.
Greetings.

• Determine Motor and Kv.

I do a calculationAlthough not scientifically correct is to find the Kv. for the engine.
Multiply consisting of RPM * 100 between 2-5 points more efficiency furtherTotalbetween the voltage used.

In this example. We look for 9954 rpm. A 70% efficiency most 5 points. Multiply by 100and divide by 75, then enter 21. We give a Kv of 632. And between 85would give us aKv. of 557. Therefore we need a motor with a KV. Among this range.

There is a rule which says that an engine must weigh at least 1 ozFor every 100 watts ofinput. But for large propeller engines would be better to consider a maximum of 85 Wattsper oz.

• As with all electric motors have efficiency losses and can not be 100%. Rather variesbetween 50 and 80%.
A good engine would give maximum power with an efficiency of 70%. 80%.

Now if 461.3 Watts. , Which is the output power is 70%. 100% will be 659 Watts. That will be our power Come to 70% efficiency.

Now if 461.3 Watts. , Which is the output power is 80%. 100% will be 576.6 Watts. Thatwill be our input power at 80% efficiency.

With 2sA deal 7.V * 94.14 = 659 Watts. 70%
With 2sA deal 7.V * 82.29 = 576 Watts. 80%

With 3s. We occupy 10.5V * 62.76 = 659 Watts at 70%.
With 3s. We occupy 10.5V * 54.86 = 576 Watts at 80%.

To 4s. We occupy 145V * 47.07A = 659 Watts at 70%.
To 4s. We occupy 145V * 41.14A = 576 Watts at 80%.

• I hope my modest explanation helps.

The type of model, the application determines the size of the propeller and the speed and power needed couple good model performance.
The weight of the model with all equipment installed is critical.

1.-To determine the rate of loss. And the maximum speed of the model
2.-Determine propeller RPM and appropriate.
3.-To determine the power required
4.-Determining Motor and Kv.

Step No. 1.

Determine the rate of loss. And the maximum speed of the model.

APC e10 x 7= 9954 rpm,
APC e11 x 5.5 =12,669 rpm,
APC e 11x 7 = 9954 rpm.
GWS hd10 x6=11,613 rpm,

APC e10 x 7= 9954 rpm, 1617g, 56oz.
APC e11 x 5.5 =12,669 rpm, 3205g, 113oz.
APC e 11x 7 = 9954 rpm. 2268g, 80oz.

a link of interest:

http://www.ecalc.ch/xcoptercalc_e.htm?ecalc

•  if you want a large prop you need a low kv motor and high output w. pid and a high rate.

in contrast with high kv motors a propeller pid small and low.
the small multicopter are more stable and agile than large ones.

the big multi great outdoors are more stable but less agile.
I use the 650 v2 XAircraft engines are very well balanced and have excellent response with 10x4.5 propellers and use 10 amp esc, with 8 of these engines have a good efficiency. multicoptero in a 650 mm diameter. and a weight of 1600 grams.

http://www.ecalc.ch/xcoptercalc_e.htm?ecalc

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