Hi guys,
Iam using thismotor in a Greatplanes Slinger and get super performance for slow to fast flying and some aerobatics. It seems to be getting pretty hot, however, and Iwas wondering what is a safe operating temperature for brushless motors? My next flight I'll remember to take my infrared <span style="font-size: 9pt; font-family: 'Arial','sans-serif'; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">thermometer</span>with me so Ican see exactly how hot it is getting but right now Ican't touch it for more than a couple seconds.
Iam using the stock prop and the canopy has a cooling port in the front of it so I'm sure it's getting sufficient airflow. If it is overheating should Iget a thinner prop?
Igeneraly keepthrottle at about center stick for normal flying which is 90 percent of what Ido so it concerns me that it gets so hot with such mild flights.

Thanks for any help,
Brian

Normally if it's too hot for you to touch, the motor is running too hot.

As the temp goes up, there is a likelyhood of the magnet glue debonding.

Also you may be pushing too much current through the motor which can lead to burning out the coil wiring in flight.

The last thing you want to see is smoke coming from your electric plane at takeoff.

I have.

I used to think that smoke is what made them work

I, early on, found out that if all the smoke is gone they will no longer run.

What is a good way to reduce the amps Iam pushing through the motor? The motor seems to handle the size and weight of the plane just fine but do Ineed to buy a bigger motor anyway? I'm a newbie at this so any help is appreciated.

Thanks,
Brian

To lower the AMPS reduce the prop diameter.

Ok, thank you for the reply. So Iget a smaller diameter but same angle on the blades? Will my motor have to sping at higher RPMs to generate the same lift? I'm guessing so but like Isaid I am new at this so don't want to make any assumptions

Lift is really generated by the wings...

The smaller diameter is going to reduce the amount of THRUST the engine produces.

The prop will spin marginally faster however and with less load on the engine. The pitch determines the SPEED of the airflow created by the prop, or you can think of it as the prop slicing through the air, or effective plane AIRSPEED.

The plane may fly at the same speed after you reduce the diameter or close to it, as would have with the bigger prop, but it will be less powerful when climbing straight up. It will take longer to get up to the same airspeed though.


Anyone who flies electrics MUST, MUST, MUST get a Watt meter ASAP.

This is the only way of accurately determining what is going on with your power systems.

Your motor is rated for no more than 266 watts constant, and this figure is in part determined by the motor's thermal limit ( it's ability to deal with heat ).

A watt meter permits you to select a propeller that will keep the motor under this range.

If you ran the motor at a constant 30A, you would fry it after a minute.

No... no.. The smoke DOES make it run. If it escapes, that's when you are in trouble.

CGr</p>

Well, just as you land if the motor smells hot, it is probably too hot

AHAH!!!

That explains why my plane failed to take off!

All the smoke left the motor!

That is correct.  Trust me!!  </p>

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Having just an opening in front of the motor for cooling air won't work if the air doesn't have any place to escape at the rear of the coweling or whatever. It must have a good flow through the cowl or fuselage.

Ok thanks! Now Ihave a place to start. Iwill try out a shorter prop and get a watt meter. Is "Watts Up?" a good one?

Thanks Guys!

The "Watt's up" meter will do the trick. While you're buying toys, if you don't have them already, think about a tachometer,and atemp guage.

As you measure... Change one ANDONLYONE thing at a time.

1. Test your current setup, and get your power measurements.
2. Change ONLYdiameter OR pitch, and measure again.

and so on..

Right down everything with each measurement.

Iknow, it's a pain, it's boring, and takes time.. but it'll be worth it.

The last thing you want to happen is seeing a blue puff of smoke come out of the motor while you're doing an inverted, low altitude, high speed pass down the runway.

If it were me.. I'd be doing such a pass while someone was video-taping...

As it turns out, it is very hard to find a local hobby shop with props smaller than 5.5 x 4.5 that could use a prop adapter. So, Ibought a new motor instead. I made sure Igot one that had a direct drive rating that could handle the 5.5 x 4.5 prop and ended up with an e-flite 6 series motor with a higher power rating and lower Kv to manage my speed better. The result was spectacular with unlimited verticals, loop after loop and all kind of silly crazy stuff with no bogging at all. As a bonus the motor was lighter than my other one so Iwas able to remove some lead weight from the nose! After 10 minutes of mixed hard to slow flying my motor was only128 degrees, the esc was about 108 and the battery barely warm tot he touch. This was an expensive lesson for me but not as expensive as it would have been if my old motor caught fire in the air so I'm happy with the results. Live and learn

Ihaven't bought a watt's up meter because the LHS didn't have any. But, Iwould still ike to get one. Would you guys recommend an on board flight recorder or the kind you use during setup and testing?

Glad to hear you've got a solution and you're flying...</p>

I followed the link, that's an interesting motor... I have a couple projects that might require such a motor.... I'll have to keep it in mind.</p>