Motors ...for beginners - please keep it simple

[Ed Anderson]

If he is going to start changing propellers he should check it with a wattmeter.  The advice you just received is to go from a 9X4.5 to an 11X6.   That is a big prop jump.    

That might be OK or it might overload the motor, the battery or the ESC.    Once you stray from the MFG recommendations you must check with a wattmeter.    

I have seen too many crashes and too many buned up components due to people bumping up the voltage or changing the prop and burning something out as a result.   They cry foul and blame the components until I put my wattmeter on and find they are pulling 40 amps against a 25 am ESC and a motor rated for 30 amp.   

Poof and all the magic smoke comes out, assuming it doesn't start a fire.

 

 

 

 

Edited By Ed Anderson on 20/08/2016 21:24:38

[Peter Miller]

I know he hasn't got one. Maybe someo has one he can borrow, we do have some other electric flyers in the club.

[Tim Mackey]

It had already been stated in the o/p that his friend didnt have a meter. The thead title is motors for beginners keep it simple.
Im SIMPLY saying a 9" prop on 72" plain model is too small. Without knowing the exact motor specs - especially max current capabilities Its impossible to be sure. However, most decent sized 950 kv motors ive used or got are fine on a 12"prop and 12v.
Mind you - what do I know 😄

Edited By Tim Mackey on 21/08/2016 01:53:27

[Ed Anderson]

 

Whether the friend has a Wattmeter or not, if he is going to play around with props he should be checking the power with a wattmeter. Don't have one?

If he doesn't want to get one he should stay with the MFG recommended, which, in this case is a 9X4.5 as reported in the post.

 

 

 

 

Edited By Ed Anderson on 21/08/2016 02:46:04

[Peter Miller]

Thanks I will pass on both comments. As I have said, I know nothing about electrics, nor does my friend. Hence the original question.

I shall suggest thathe stays with the original prop and then try bigger ones if the performance is lacking.

[Ed Anderson]

That is a good approach.

 

Wattmeters are an essential piece of kit for electric flyers who are moving away from Ready to fly or bind and fly packages.   As you change props or battery voltage you change the power curve of the motor.   As a result you can overload something leading to component failure.  So you check with the wattmeter to insure that you are not overloading the motor, the ESC or the battery.

They are not expensive.   I have two.

Here is an example of a wattmeter from HobbyKing.

http://www.hobbyking.com/hobbyking/store/__14624__HobbyKing_PO_Wattmeter_100A.html

 

 

Edited By Ed Anderson on 21/08/2016 14:51:19

[kc]

A wattmeter will save it's cost the first time it saves an ESC!

[Tim Mackey]

Posted by kc on 22/08/2016 12:43:42:

A wattmeter will save it's cost the first time it saves an ESC!

Yup

[Steve Adams]

Hi Everyone,

I have an old ic balsa and ply model aircraft that my mate(who is no longer with us) built me and was his own design and was powered well with an Enya 40 two stroke. My question is this plane is 2.5 kg dry 58 inch wingspan mid wing sport trainer,what would be ideal set up on electric ie motor,esc and battery please? Cheers 

 

Steve😎👍

 

[Tom Gaskin 1]

Hi Steve,

I would look at an elite Power 46 on 4 cells. The motor is quite expensive so you could note down the specs (motor can length & diameter, rpm per volt (KV) operating voltage and then do an internet search for an equivalent.

 

Length 55mm

Diameter 50mm

KV 670

Voltage 4 to 5 cell Lipo

 

Tom

[Chris Walby]

Could phone George at 4Max, with his experience he'll be able to quote ECS, motor, prop and lipo that best suits the model in question.

[Shaun Walsh]

3 hours ago, Steve Adams said:

Hi Everyone,

I have an old ic balsa and ply model aircraft that my mate(who is no longer with us) built me and was his own design and was powered well with an Enya 40 two stroke. My question is this plane is 2.5 kg dry 58 inch wingspan mid wing sport trainer,what would be ideal set up on electric ie motor,esc and battery please? Cheers 

 

Steve😎👍

 

Assume 6lbs AUW. Minimum power requirement approx 600 W. Assume 4s battery, current draw is around 44 Amps. Therefore 60A ESC to be on the safe side. Motor kv will depend upon prop size required 12 inch would be a good starting point, possibly bigger if there's enough ground clearance. 6 inch pitch would be a good starting point.  

[Shaun Walsh]

Something like this might be appropriate 

https://www.overlander.co.uk/rc-motors/outrunners/3548-05-900kv-tornado-thumper-v3-brushless-outrunner-rc-motor.html

I'll run the numbers through propCalc when I get home.

Edited August 16 by Shaun Walsh

[Steve Adams]

1 hour ago, Shaun Walsh said:

Something like this might be appropriate 

https://www.overlander.co.uk/rc-motors/outrunners/3548-05-900kv-tornado-thumper-v3-brushless-outrunner-rc-motor.html

I'll run the numbers through propCalc when I get home.

Thankyou so much,I used to fly ic in the 90s and only been back in the hobby a year or so,wow so much has changed,but I don't know much about electric set ups and I'm keen to preserve this airframe as sentimental to me but I want it flying again also.

[Shaun Walsh]

15 hours ago, Shaun Walsh said:

Something like this might be appropriate 

https://www.overlander.co.uk/rc-motors/outrunners/3548-05-900kv-tornado-thumper-v3-brushless-outrunner-rc-motor.html

I'll run the numbers through propCalc when I get home.

i've run the numbers in propCalc assuming a 4s 4000mAh battery, 60A ESC using a 12x5 APC-E prop and these are the results

 

 

 

 

Edited August 17 by Shaun Walsh

[MattyB]

On 21/08/2016 at 09:09, Peter Miller said:

Thanks I will pass on both comments. As I have said, I know nothing about electrics, nor does my friend. Hence the original question.

I shall suggest thathe stays with the original prop and then try bigger ones if the performance is lacking.

Ok, but please suggest he gets a wattmeter first before making any changes otherwise anything he does to the powertrain  is likely to get expensive very quickly! 

[Shaun Walsh]

21 minutes ago, MattyB said:

Ok, but please suggest he gets a wattmeter first before making any changes otherwise anything he does to the powertrain  is likely to get expensive very quickly! 

Probably a bit late Matty, that's a 8 year old post 

[MattyB]

10 minutes ago, Shaun Walsh said:

Probably a bit late Matty, that's a 8 year old post 

Sorry, this is the kind of confusion that can easily occur when people bring  an ancient thread back to life rather than starting a new one! As @Steve Adams did here with this thread. Thread necromancy should be banned! At the very least there should be a warning that pops up when you try and post to an ancient thread, suggesting you start as new one instead, Mods, could this feature be turned on? Thx, Matt

Edited August 17 by MattyB

[Cuban8]

17 hours ago, Chris Walby said:

Could phone George at 4Max, with his experience he'll be able to quote ECS, motor, prop and lipo that best suits the model in question.

Unless one is prepared to quite a bit of research into what is not exactly a straightforward process for those who know nothing or very little of things electical, then to avoid expensive errors I'd say George is the best way forward.

[Steve Adams]

On 17/08/2024 at 09:53, MattyB said:

Sorry, this is the kind of confusion that can easily occur when people bring  an ancient thread back to life rather than starting a new one! As @Steve Adams did here with this thread. Thread necromancy should be banned! At the very least there should be a warning that pops up when you try and post to an ancient thread, suggesting you start as new one instead, Mods, could this feature be turned on? Thx, Matt

Sorry for that,didn't mean to cause confusion and upset as result 👍

[MattyB]

2 hours ago, Steve Adams said:

Sorry for that,didn't mean to cause confusion and upset as result 👍

No upset caused it is just with my only partially functioning post -strike brain it is hard to spot stuff like the start date of a thread so I do think the forum ought to have features that actively prevent very old threads n brought back to life! As many other forums do.