Brodak's Day 5 ( results )

[Will Davis]

Great end to a perfect week, Congratulations to all contestants .

[peabody]

I judged Expert PA.....and think that District II PAMPA rep Buddy Weider did a terrific job as well.....
Mike flew with the same electric set-up that he has been using, including conventional prop. Mike's plane SOUNDS different than other electrics...
It should be noted that young Daniel flew his well-worn Vista....with 8 appearance points...Mike received 17, I believe and Joe 16...
Have fun!
 

[Ted Fancher]

I judged Expert PA.....and think that District II PAMPA rep Buddy Weider did a terrific job as well.....
Mike flew with the same electric set-up that he has been using, including conventional prop. Mike's plane SOUNDS different than other electrics...
It should be noted that young Daniel flew his well-worn Vista....with 8 appearance points...Mike received 17, I believe and Joe 16...
Have fun!
 

P'body,

I'm fascinated by your comment re the noise of Mike's electric.  I at one time pontificated at great length (big surprise, huh) about the sounds--most of which come from the prop, not the motor--of electrics and how they seemed to amplify maneuver shape distortions particularly in squares and triangles.  The tattle tail apparently coming from the loading and unloading of the prop, making a distinctively noticable "varroom" at a higher decibel level.

How would you characterize the difference in sound of Mike's ship and do you (or does he) have any idea what is making the difference???

Ted

[REX1945]

I can't quite read the scores.

Any chance you can send a larger file ?

Rex

[Will Davis]

Better set of Pics, the others were compressed too much

[Mike Palko]

P'body,

I'm fascinated by your comment re the noise of Mike's electric.  I at one time pontificated at great length (big surprise, huh) about the sounds--most of which come from the prop, not the motor--of electrics and how they seemed to amplify maneuver shape distortions particularly in squares and triangles.  The tattle tail apparently coming from the loading and unloading of the prop, making a distinctively noticable "varroom" at a higher decibel level.

How would you characterize the difference in sound of Mike's ship and do you (or does he) have any idea what is making the difference???

Ted

Ted,

I agree it is most likely prop noise. I think it has to do with prop stiffness and how tight the corner is. Round maneuvers make little to no noise while squares have a pronounced bight in the corners. I like it. Of course there could be other factors like prop shape, governor effectiveness etc... but I think they are less likely to be the reason.

The majority of people flying electric use APC-E props which are not very stiff and I would expect they are distorting in the corners reducing the prop noise. I also think a lot of people fly softer corners than I do (or try to do).

Thanks to Rich, Phil and Bob for judging expert.

Mike

[peabody]

Thanks Mike....
Yup Ted....it's pretty much what Mike describes....makes a nifty buzz when doing tight maneuvers...not so much on rounds...
Glad young Daniel found his Clown...I imagine boring and stroking an LA 15 took some time\.......

[Ted Fancher]

Mike and Rich,

Are all the electric guys running pretty high pitch props or are there some that go each way on that?  Is the more forward CG that Paul is keen on universal or do some of you run CGs back where the heretofore "modern" ~25% or so IC ships were running?

I'm thinking that differences in prop pitch and load (drag) from tight corners with forward versus aft CGs might have a significant effect on prop noise...and the possibility of pitch flexing with the E-props might also.

Rich, how would you characterize the "difference" in sound?

Ted

p.s.  Sounds like Brodak's was a big one!

[Dennis Toth]

Ted,
Here in Florida we are running 6" ish pitch at around 9000 rpm. At this setting there is still a distinct sound as the ship flies through the corners and at the top of the vertical eights. You can hear the motor load up and power through. I have found that the low pitch / high rpm draws higher current (fuel therefore weight) than the more conventional set ups resulting in the need for larger batteries and more weight. This is the balancing act with electric, we can have any amount of power you want from the motor it just needs more amps and you need to carry the additional mah in the battery pack. I have tried various props wood and carbon and the noise comes from an inefficient tip shape. I'm still working on comparing the performance of a good stiff prop to the APCE thin ones. So far there hasn't been anything that jumps out as superior.

Best,        DennisT

[proparc]

P'body,

The tattle tail apparently coming from the loading and unloading of the prop, making a distinctively noticable "varroom" at a higher decibel level.

Ted

The big F3A electric ships make that sound-but much loader. Ted you should hear an F3A contra drive!!

[Mike Palko]

I have tried various props wood and carbon and the noise comes from an inefficient tip shape.

Best,        DennisT

Dennis,

If the noise was solely from an inefficient tip shape it would be heard throughout the flight, not just in corners.

Mike

[Will Davis]

Palko's Flight , hope you can hear the noise , I like the way it sounds

[Robert Redmon]

In my case, I hear a very noticeable corner "growl" only on one airplane. It runs an APC 11x5.5 "e" tractor prop (the newer, thicker bladed version pitched up to 11/6.5 on my Prather) @ 9200 rpm. The "growl" is noticeable only in tight inside corners....not in outside corners (tight or not) or any of the round maneuvers. Good going at Brodak's, Mike.

Bob

[Dennis Toth]

Mike,
On various props I've tried, you do hear the prop noise through the whole flight when its inefficient. This is the one thing about electric that tells you that its wasting power. On IC's they can't hear the prop noise to know when the prop is not working. On my ships there is a slight change in overall motor/prop noise as the ships loads and unloads the motor even with very efficient APCE props. You can only hear it if no one else is flying IC.

Best,          DennisT