Trial & error matching electric system
 

Hello



Since I fly RC electrical energy system , I realized I had to check sum Fixation

For example:
When I fly a gas engine the propeller match is the manufacturer data and experience of others with the same engine, thes was the only things I was looking for, while I completely ignoreing the model,
The same fixation was in the Start fo my electric flying ...
but I had a lot of question marks .



Another thought was the Outrunner being less efficient fom Inrunner + gear?

Today I am doing trial & error using different propellers and different motors
I gathered information through EAGEL TREE checking for various .



I checked the motors:
Hacker C50 13 XL COMPO gear 6.7 / 1
Hacker C50 14 XL COMPO gear 6.7 / 1
Plettenberg Xtra 30-10 Evo



Different propellers
22X12
21X14.5
21X15
20X13



The model & batterys stays the same .
I wanted to create a situation that I do not have to change the model with the ability to go back for this test

Shlomi Chester
F3A Israel

RE: Trial & error matching electric system
 

sum EAGEL TREE

Hacker 13XL 20x13
Hacker 14 XL 22x12

RE: Trial & error matching electric system
 

Personally, I would be more interested in watts (volts @ amps) and rpm. Cumalitive mah and temp isn't very useful to me for comparative purposes between motor/prop combinations. YMMV tho.

Woodie
Team Acme LG

RE: Trial & error matching electric system
 

Hello Shlomi,

I find your testing very interesting. Your test mount is very nice! I hope you will do much more testing and share more information, but Woodie is correct. If you already know this, please forgive me:


When testing electrical systems, you must measure the power in and the power out. The power in is the volts and amps. You can see the power out from the RPM of the propeller.


Also, for the motors you are testing, many people here on RCU have already tested these motors and propellers over and over. I believe the consensus is:

1) Inrunners are more efficient, but most people can not tell the difference during 8 or 9 minutes of practice.
2) The 20.5 x 14 propeller is the best overall compromise size for a 5000g/3000 watt e-system.
3) Outrunners are preferred by many because they require no maintenance.
4) The 30-10 has much more top end power than the geared Hacker motors.


If you search more on RCU, I am sure you will find much more information and many more opinions.



Anyways . . .




What kind of plane are you flying using electric?

Is electric or glow more popular in your club?

Is this your first electric plane?


Just curious, and I hope I was not saying something too obvious ;)



Joe

RE: Trial & error matching electric system
 

Hello Joe



Exactly what you write and others write, I try to prove or disprove .
I believe that models have a different working point - flying at different speeds with different style
I personally have difficult to establish such general things to all spectrum of options
so I want to show the work I have done on the specific model that I'm flying in the style I emphasizes (my model has a lot of dragge & it is flying very slowly ),
I want to show how different it is from the familiar general formula ,that's all .

I have a problem with assumeing that the rpm Remained constant =constant Watts? in flight?
The watts will change when the load on the propeller varies, it depends on the speed of the Air flow on the propeller .
so when ther is larger gap between the rpm & Watts can we assume it is mor eficient ?
But everything changed in flight , no one Can fly perfect ,
At least I can't
So maybe we need to use average rpm & average Watts
I have no problem providing the data

I fly the Osmose of CA is my third electric model, after an Intgrl of CARF& Beryll of OXAI
The Clubs I belong to are 50% electric F3A today

I work every day ,regardless F3A, in electric aviation

Shlomi Chester

RE: Trial & error matching electric system
 

First, I apologize for the slowly Supply in the information
I am editing the it during thes days.


So. I checked on 30-10 EVO the 21X15 and 21X14.5 in the same method
Out in the spiner without changing the model yet .


Energy demand in p11 schedule is less in general (for slow flying style)


Shlomi Chester

RE: Trial & error matching electric system
 

It appears the 2 charts in above message are the same chart.

Woodie
Team Acme LG

RE: Trial & error matching electric system
 

You're right
Here it is

RE: Trial & error matching electric system
 

Hello


All the questions originated from problems due to basic assumptions,
attempt to find the sclution I also began to understand better the problem (it's a natural process)

The problem was the Power Consumption when I fly very slowly relatively constant series of P11/F11

HACKER C5013XL
20X13 PROP received power in the 4000 MA P11 flight of 5000 it was plenty

In retrospect: not suitable for my model
It is for those who love to fly faster F3A

I got another lesson about the “big differences” between Outrunner considered less efficient

Again I found efficiency propeller is the Major dependent .
The differences between inrunner+gear 89 % to outrunner 87 % should not determine when Choose the motor fit
The best propeller suitable to the model and the motor that can turn this propeller wthe efficiency should be it .

I found my model like the propeller 22X12
This propeller should be a very big load on the motor = a lot of Power Consumption,
But it turned out well mor Economical when flying appropriate speed.


The logs wer after I let myself learn the new system on the model , understand the system and it is not the first flight after changing the system & Attempt flying at the same speed.
The fact is that the time it takes all series by the graph ,which means that almost one Variable is Tested (as far as hand-eye know how to fly precision)

RE: Trial & error matching electric system
 

I made more changes:D