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Author Topic: Super-Fil  (Read 10376 times)

Offline Dan McEntee

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Re: Super-Fil
« Reply #50 on: March 02, 2019, 07:53:32 AM »
   Just to add to the thread drift, I think you really need to pay attention to air flow more so with the electric set ups than with an engine.Too much intake and not enough exhaust for the air will cause a stagnant bubble inside the fuselage. There are three components to consider, battery, speed control, and motor, and they are all in a "stack" or pile and the motor is in front and in the way! I like starting with Bubba's annular ring around the spinner for the intake, and maybe have a small opening in the cowling that you can start off with it taped over. Have the batteries and controllers arranged to not be in contact with each other and have airflow around them, and then plenty of exit grills. When the trend in full scale aircraft restoration of Hawker Sea Furies went to an engine swap, the cooling inlet was an annular ring opening between the spinner and the cowling lip. You could barely fit your fingers in the gap, but plenty of places at the back for air to escape. I haven't done any electric stunt but did quite a bit of electric assist R/C soaring and this is pretty much what we did. The power train components were not under load as long as a stunt set up, but were worked very hard for shorter periods of time during a climb. we didn't have any modified spinners like this one depicted, but I'm thinking that the only time any air gets through is when it isn't spinning!
  Type at you later,
  Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Ken Culbertson

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Re: Super-Fil
« Reply #51 on: March 02, 2019, 10:26:12 AM »
   Just to add to the thread drift, I think you really need to pay attention to air flow more so with the electric set ups than with an engine.Too much intake and not enough exhaust for the air will cause a stagnant bubble inside the fuselage. There are three components to consider, battery, speed control, and motor, and they are all in a "stack" or pile and the motor is in front and in the way! I like starting with Bubba's annular ring around the spinner for the intake, and maybe have a small opening in the cowling that you can start off with it taped over. Have the batteries and controllers arranged to not be in contact with each other and have airflow around them, and then plenty of exit grills. When the trend in full scale aircraft restoration of Hawker Sea Furies went to an engine swap, the cooling inlet was an annular ring opening between the spinner and the cowling lip. You could barely fit your fingers in the gap, but plenty of places at the back for air to escape. I haven't done any electric stunt but did quite a bit of electric assist R/C soaring and this is pretty much what we did. The power train components were not under load as long as a stunt set up, but were worked very hard for shorter periods of time during a climb. we didn't have any modified spinners like this one depicted, but I'm thinking that the only time any air gets through is when it isn't spinning!
  Type at you later,
  Dan McEntee
Dan:

one day at our flying site I happened to have my hand over one of the exhaust ports on my plane when I hit the start button.  When the prop spun up for that short burst I felt a rush of air coming out of the exhaust.  However, I see no real difference in the motor temperature at the end of a flight using this spinner.  I think you are right, at operating rpm it has no effect.  But...they do look cool!

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline john e. holliday

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Re: Super-Fil
« Reply #52 on: March 03, 2019, 10:14:25 AM »
If you had your hand over the exhaust hole of the plane, the air you felt has to be the air that 2 stroke engine is pumping.   D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Offline Ken Culbertson

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Re: Super-Fil
« Reply #53 on: March 03, 2019, 12:58:51 PM »
If you had your hand over the exhaust hole of the plane, the air you felt has to be the air that 2 stroke engine is pumping.   D>K
So what do you call the holes in your airplane where the air goes out?

ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC


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