Bill Clark

well, atleast I think its a new idea. I really enjoy coming up with new things or refining existing ones. My latest project has been a Sebart Wind 110e. I have found from experience that keeping motor tempsvery coollets you run them harder (dah!!!). The nose area and firewall on the Wind just about makes it impossible to effectively move air through the motor and around the windings. I have found this type of airflow to be critical with outrunners. After thinking about the problem I came up with a solution that just may be the ticket. A little lathe work on a GP spinner and a trip to Skycraft for a circuit board fan to scavange the impeller fromnetted something I think looks pretty cool and just may work. Data aquisition on the plane will confirm just how much of an improvement, if any this will provide. I will be taking steps to seal the back plate to the nose and around the propeller blades to make surethe airflowhas no place to go but through the motor. spinning it up with out the prop in place looks promising.

klhoard

My Feedback: (10)

.That looks Kewl (as my kids would say) . . ..

rgreen24

My Feedback: (6)

Bill keep us posted on the progress after you run it.

flyintexan

My Feedback: (1)

Nice work!

I wonder if the pitch speed of the fan blades will need to be higher than that of the propeller to create a positive pressure behind the fan?...


Good luck,
mark

Bill Clark

good question Mark. This is one of those "try and see" projects with information coming from a temp probe stuffed down in the windings. I plan to run it with the fan, without the fan, just having a big hole and with a stock spinner. there are a lot of variables and I'll post the results.  Hopefully it just works and doesnt turn into another one of "those" projects. FYI the blades are angled at 35deg has a 7/8" dia hub and is 1 7/8 on the outside. Probabley just sealing everything up (there is seperate cooling blowing on the outside of the motor) leaving the air no where to go but through the motor will be the biggest gain.  I am changing alot of things on the plane so I'm still a few weeks out from its maiden voyage.

rix

When I was flying a Wind110 I had a Hacker A50-16L V1 in it and it would get really warm so I cut the cone on the stock spinner and it seemed to help a little. A friend has a V2 in his and it runs much cooler than mine ever did. Your idea should really be of benefit I would think.

serious power

Hi Bill,
Look here it does work;

http://www.rcuniverse.com/forum/m_67...tm.htm#6778623

Brian

EHFAI

Some time ago I made some measurements comparing the air speed behind the spinner of Tru-Turn spinners with their lightened backplate and with their Turbo-Cool spinner which has fan shaped spokes on the backplate and openings in the cone. http://www.truturn.com/cgi-bin/store...30&maxp=30

I chose to measure airspeed, as motor temps are very dependant upon air ducting. Measurements were taken in flight using a pitot tube mounted 1/4 inch behind the spinner at a midpoint between the shaft and outer diameter.

Results with no spinner, a standard spinner / solid backplate, a standard cone / lightened backplate / and the fan backplate - vented cone indicate the most flow speed with no spinner (comparison point for others) and no flow with the solid backplate / cone.

The lightened backplate and solid cone resulted in airspeed of 35% that observed with no spinner. (This cone had larger than necessary prop cut-outs.)

The fan backplate / vented cone provided 60% of the airspeed provided with no spinner (and looks way better). 

My conclusion is that a spinner with an internal fan and cone openings provides significantly more airflow than other systems. The cooling benefit of the extra airflow is highly dependant upon how the air flows through / over the motor.

underdw

My Feedback: (2)

Nice work Bill!
Please let us know the effects on current/power and rpm too.