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Old Dec 11, 2012, 03:51 AM
The props of tomorrow
Varna , Bulgaria
Joined Feb 2007
960 Posts
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Originally Posted by Dotcom View Post
Very interesting stuff, I am following with interest. In fact, I can hardly wait for the first flight with what I soldered up tonight. Unfortunately the Leo doesn't fit in the B06 fuse. Needs a nose job


Greets, andy
Why don't you just put a longer spacer between motor and fuse motor mount ?
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Old Dec 11, 2012, 04:09 PM
Registered User
Winterthur, Switzerland
Joined Aug 2003
127 Posts
Quote:
Originally Posted by GeorgiMirov View Post
Why don't you just put a longer spacer between motor and fuse motor mount ?
The spacer would need to be 8mm thick, with some squeezing 7mm at least. This would leave just 8mm of shaft to be clamped in the propeller which sounds very little... or is that too cautious?

The bottleneck is the motor case aft of the gear where the winding starts. The Leomotion is at this point short of 40mm in diameter while the Neu is 39mm and mainly, the gearbox is longer. Putting in a new motor mount at the required location and shortening the fuse by ca 4mm and removing the old motor mount seems to me the only way to fit the spinner to both the gear shaft as well as the fuse diameter

On the topic of ramps, with my limited electrical understanding I have the following question: Earlier in the thread it was suggested to have the ramp programmed in the transmitter, and choosing the controller parameters as above. I use the throttle on an on-off switch in the transmitter (where a ramp profile or a delayed/soft-start can easily be programmed). But from a controller point of view, would it not make more sense to provide the controller with just the desired final values (i.e. on or off) and have the ramp done entirely by the software of the controller? If the ramp is included in the signal rather than just the on or off, the controller needs to match the motor speed constantly to the provided value during ramp-up. Does my question make sense?


Cheers, andy
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Old Dec 11, 2012, 05:20 PM
The props of tomorrow
Varna , Bulgaria
Joined Feb 2007
960 Posts
The given settings will follow exactly the ramp of your radio. The settings themselves won't make a ramp. It's just the right settings to have a smooth ramp via Futaba Tx. Not sure what you have, I know graupner MC 20 and above can do it as well.
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Old Dec 23, 2012, 11:09 AM
Battery Puffer
Orange, California, United States
Joined Nov 2001
1,128 Posts
I flew my enigma and noticed the prop cavitated alot before hooking up. More than it should I thought.I have a Georgi 18 x 21 prop and no ramp. I am going to change over to my futaba 9c radio and wondered if anyone could help me with the ramp settings. Thanks for your help guys.

Mark
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Old Dec 23, 2012, 05:22 PM
Livin it UP when Im goin DOWN
Arcteryxxx's Avatar
Norway, Telemark, Skien
Joined Feb 2010
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Quote:
Originally Posted by MarkF View Post
I flew my enigma and noticed the prop cavitated alot before hooking up. More than it should I thought.I have a Georgi 18 x 21 prop and no ramp. I am going to change over to my futaba 9c radio and wondered if anyone could help me with the ramp settings. Thanks for your help guys.

Mark
+1, except for the radio part. Anyone with Spektrum DX8 with this one figured out?

Best regards and Merry Christmas to you all.....
Arcticfreezingmybuttsoffteryxxx.....
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Old Dec 23, 2012, 08:17 PM
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Singapore
Joined Aug 2006
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Look at Joe Morris' blog for throttle ramps.
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Old Dec 25, 2012, 06:55 AM
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Italy,Russia,Kazakhstan...
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There is a very small and virtually harmless error in his reasoning.
Not "power curve to speed" function but "RPM curve to flight speed" to maintain the optimum angle of attack (pitch) of the propeller blades and minimum energy consumption. Throughout the rev range and flying speed.
In the future you will choose the motor that will be able to do the right curve of RPM's with minimum power consumption.
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Old Dec 25, 2012, 11:41 AM
Battery Puffer
Orange, California, United States
Joined Nov 2001
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Here is a graph of my short run. The volts avg. was 38.4, the rpms were 9200 and the amps around 159. How do these numbers look for my setup?

Mark
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Old Dec 25, 2012, 12:01 PM
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Singapore
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Hi Mark,

Zoom in real close on your 2nd or 3rd climb. Have the x axis show 3 seconds of your climb. That way it's easier to see what your power curve looks like vs time. I hope your data log is set to 10hz recording frequency.
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Old Dec 25, 2012, 12:02 PM
Needs to do 52 legs !!
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Verenigd Koninkrijk, Fareham
Joined Aug 2008
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Originally Posted by MarkF View Post
Here is a graph of my short run. The volts avg. was 38.4, the rpms were 9200 and the amps around 159. How do these numbers look for my setup?

Mark
Hi Mark, not sure what you are asking. As usual you can not see much on a ICE graph. Much better is Roy's program with a Unilog 2.

Vladimir, yes it is the angle of the prop to the air that is important and this is a function of forward speed and RPM. RPM is very closely linked to the power, so failing an airspeed sensor and an RPM sensor you can just look at the Watts and try to make a reasonable curve.

For now it suffices to say that the efficiency of the prop is bad but no a total loss when you hear it stall. It is worth trying to make the prop silent however beyond this you will be surprised how little difference it makes to the total performance of the drive system.

Some time in the near future I will do another blog to talk about prop performance and to help people understand what is really going on up front. I think many people will be surprised to learn what the angle of attack is doing at various places. I bet most people think that when the prop stalls they think the entire blade is stalled or the outer part of the blade. Not so!

I got myself an ICE2 160HV for X-mas and will have a close look at it. Compare it to the much cheaper 6S option I have for sale and report back to you.

Merry Christmas to all.
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Old Dec 25, 2012, 12:19 PM
Battery Puffer
Orange, California, United States
Joined Nov 2001
1,128 Posts
I guess what I'm asking is how do my amps and avg. voltage and so on compare to what others are getting on there same 10s setup. I think my amps are low for instance.

Mark
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Old Dec 25, 2012, 12:39 PM
Needs to do 52 legs !!
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Verenigd Koninkrijk, Fareham
Joined Aug 2008
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Originally Posted by MarkF View Post
I guess what I'm asking is how do my amps and avg. voltage and so on compare to what others are getting on there same 10s setup. I think my amps are low for instance.

Mark
Mark, you haven't told us if it was an actual flight or a static run. I don't know what prop you are running either. This will effect the power and RPM.

Further more, AVG voltage from the ICE or Unilog means absolutely nothing. We want to know the behaviour of voltage under load and this you can only see in a proper graph. As Dennis said, try zooming in on one motor run only and maybe also only display 3 things at a time so we have a chance to follow the lines.

It sounds like your setup is working normal tho.
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Old Dec 25, 2012, 12:50 PM
Battery Puffer
Orange, California, United States
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Thanks for the help guys. This was an actuall flight and I'm running the 18 x 21 Georgi prop.

Mark
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Old Dec 26, 2012, 02:42 AM
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Italy,Russia,Kazakhstan...
Joined Aug 2007
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Originally Posted by jjmouris View Post
....................................

Vladimir, yes it is the angle of the prop to the air that is important and this is a function of forward speed and RPM. RPM is very closely linked to the power, so failing an airspeed sensor and an RPM sensor you can just look at the Watts and try to make a reasonable curve.

For now it suffices to say that the efficiency of the prop is bad but no a total loss when you hear it stall. It is worth trying to make the prop silent however beyond this you will be surprised how little difference it makes to the total performance of the drive system.

Some time in the near future I will do another blog to talk about prop performance and to help people understand what is really going on up front. I think many people will be surprised to learn what the angle of attack is doing at various places. I bet most people think that when the prop stalls they think the entire blade is stalled or the outer part of the blade. Not so!
.................................................. .............................................
Merry Christmas to all.
Of course the power curve can provide some understanding of the process. But if you really want to have an effective system (and not to use SM 150A shunt and 8S setup in the competition), and then only the effectiveness of the propeller will stop you. For example, some known to me propellers have a maximum efficiency at the blade angle of attack of about 6 degrees. And to increase the angle of attack to 9 degrees, prop does not stall. But does accelerate just less effective. You spend more energy. In order to achieve the same result on the speed and altitude.

For different flight speeds effective angle of attack of the propeller, is also different. Propeller thrust at different flight speeds, also differs. And it is just that-propeller and how it leverages the shaft rotation transforming it into motion model and is primary. Secondarily, is the effectiveness of the motor which is powered by battery and converts it to rotate the shaft.

This is the basic theory. Physics of motion.

Thus, just for your propeller, and for flight conditions F5B, form the RPM curve, making the most effective use of the propeller in the first place. And then choose the motor that will provide this RPM curve with minimal energy consumption. Easy, no?
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Old Dec 26, 2012, 07:25 PM
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United States, CA, San Diego
Joined Dec 1999
7,359 Posts
Picture from the spy center The new year brings a new controller.

It has some useful features--including "short circuit protection" which could prove useful.

Steve
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