Originally Posted by dead

I just stumbled on a curiosity. PA's Thrust 40 vs. Torque 2814T/820

The torque is 143 gr and good to 38 amps (Peak or Constant Unknown?) and 500 to 550 Watts.

The KV is 820 and they recommend a 13 x 6.5 on 3s

The Thrust 40 is 850KV only 140 grams and is good to 500 watts and 35 amps constant and 45 amps 10 sec burst and they recommend a 14 x 7on 3s. The Thrust motor does not specify what 4s prop to use, only that you should stay within the suggested amps.

Is the Torque motor under rated? Could you safely put a 13 x 5 or 13 x 6 on it with 4s? I would think the lower KV of the Torque would allow for higher prop sizing?

I been using the Torque with 4 cells APC 13 x6 never an issue but now I like the 12 x 6 APC prop less power....

Originally Posted by frankjp

OK,,,Can't resist this. I'm good at making "Half Props" so I cleaned one of these up ,,,(hacksawed it through the center),, and weighed it. The prop was a Turnigy Light Electric 16x8. I don't have one xactly like what you are testing but this method should get us some spool up data Right?
The total (half) is 20.5 grams 41gr before landing? It balances on my Buck Knife at 2.66",(67.53mm),from center hole which would be center of mass right?
Tip 6.9 gr
Ctr 13.8 gr
Center mass Dia 5.32" /135.06mm

It gained a couple grams at my Harbor Freight/ one car garage lab.
Worth while ?? or do I have to go sit in the stands?

Very Clever and simple solution which are often the best!

For years my company spent millions on complex inventory management systems to predict and replenish production floor stk. However far a simpler method was employed a box containing a predetermined number parts that when emptied on the production floor visually signaled replenishment. And the box (Kanban) works far better than any complex software algorithm. Simpler is almost always a better solution.

Again Nice work Frank.

Originally Posted by Tom K.

A friend of mine had a vacuum chamber big enough for this... but he kinda fell of the radar a year or so ago. You remember James right?

--Tom K.

Oh yes,,James would be like this.


Tom, how about for this test we blindfold you while we switch props,put the plane in the air,hand you the Tx,fly it,land it at the end of the runway,then make your analysis. You need a little pressure too. Oh ya ,we'll pull the blindfold somewhere in there.

Originally Posted by leespaddock

Very Clever and simple solution which are often the best!

For years my company spent millions on complex inventory management systems to predict and replenish production floor stk. However far simpler method was employed a box containing a predetermined number parts that when emptied on the production floor visually signaled replenishment. And the box (Kanban) works far better than any complex software algorithm. Simpler is almost always a better solution.

Again Nice work Frank.

Thanks Lee,

If you are going to put Tom in the Aero industry ,,do it in the next couple weeks OK.
We have a new 10 year old at our field that just got his wings and is following Tom very close,talking 3d trash, so there will only be short window of opp. for Tony and to try to be King again. LOL

Originally Posted by flazo

I been using the Torque with 4 cells APC 13 x6 never an issue but now I like the 12 x 6 APC prop less power....

How many amps were you pulling?

Originally Posted by dead

http://rcwebclub.com/LinkClick.aspx?...%3d&tabid=1208

This is the Analysis to go along with Leespaddock's testing...

Okay, I’m on board now. Thanks, Dead, and thanks for linking my analysis. Here are some important things to remember about what I have done.

Although it has been 31 years since I had to defend an independent study, the process is the same – to use scientific standards and address the data only, with no hypotheticals, in a way that you can defend it. Good questions are things like “why did you do it this way” or “why did you not use this technique”, but if the data is addressed objectively, and without agenda, then these questions are easy to answer.

One thing to remember is that I focused on developing a prop constant (pK) from Lee's very fine data, because it provides a means for comparison. Unless I made a math error, these constants can be plugged into the Watts formula so that using the same efficiency rating (84% was linear), the prop diameter, the prop pitch, the Kv of the motor, battery cells, battery mAh, measured volts, RPM’s, and Amps, are all relative per sample, per pK. Resistance, lost Amps, heat, and the difference between measured Watts and kinetic Watts was illustrated.

This was achieved and produced for WOT and the half-throttle setting. The volts, across the board, and the difference in RPM increase from half to full, were constant enough to be statistically acceptable, keeping in mind that the RPM increase for nearly all the samples was 33% from half setting to full setting and not 50%.

I will try to review all the posts so far to see if there are any questions about the analysis that I have not answered, but I think this thread can become a very productive thread if each of us continues to contribute by recording and sharing data. My focus for now will be to try some in-flight comparisons, using video, so we can hopefully see differences during maneuvers we are used to performing, or seeing others perform.

I feel that this is an important discussion for one main reason… to get the most out of a very fine airplane. This means a balance between motor size, motor weight, Amps, heat, and flight time. For most of us, turning a bigger prop at a lower RPM with reduced prop stall and higher torque is the ultimate goal. Sometimes this is all about disk diameter and pitch, but the prop constant will also tell us about performance relative to load.

Feel free to PM me if there is a question about my analysis, but feel free to run with the data too, or duplicate the test and present different data, or try new propellers in this size class. This should be fun for some of us, but crazy boring for others. Such is life.

Originally Posted by dead

How many amps were you pulling?

I don't know anymore but I must say I was using a throttle curve...

and was able land like a Heli


fred

Originally Posted by Tom K.

If you want to swing a big prop on 4S, the Motrolfly 2820-750 will swing a 14x7 on 4S at 7900RPM's at about 35 amps constant. My custom Motrolfy 2820-750 with 680 kv (comes stock with 630) will swing a 14x7 8200RPM's at about 45 amps producing almost 10 pounds of thrust.

--Tom K.

The 2820-750 now come wound to about 683Kv

Ken

Tom,
Should only be about 6lbs thrust.

Ken

Thanks Ken for stopping by with good information

Originally Posted by Aeroplayin

Okay, I’m on board now. Thanks, Dead, and thanks for linking my analysis. Here are some important things to remember about what I have done.

Although it has been 31 years since I had to defend an independent study, the process is the same – to use scientific standards and address the data only, with no hypotheticals, in a way that you can defend it. Good questions are things like “why did you do it this way” or “why did you not use this technique”, but if the data is addressed objectively, and without agenda, then these questions are easy to answer.

One thing to remember is that I focused on developing a prop constant (pK) from Lee's very fine data, because it provides a means for comparison. Unless I made a math error, these constants can be plugged into the Watts formula so that using the same efficiency rating (84% was linear), the prop diameter, the prop pitch, the Kv of the motor, battery cells, battery mAh, measured volts, RPM’s, and Amps, are all relative per sample, per pK. Resistance, lost Amps, heat, and the difference between measured Watts and kinetic Watts was illustrated.

This was achieved and produced for WOT and the half-throttle setting. The volts, across the board, and the difference in RPM increase from half to full, were constant enough to be statistically acceptable, keeping in mind that the RPM increase for nearly all the samples was 33% from half setting to full setting and not 50%.

I will try to review all the posts so far to see if there are any questions about the analysis that I have not answered, but I think this thread can become a very productive thread if each of us continues to contribute by recording and sharing data. My focus for now will be to try some in-flight comparisons, using video, so we can hopefully see differences during maneuvers we are used to performing, or seeing others perform.

I feel that this is an important discussion for one main reason… to get the most out of a very fine airplane. This means a balance between motor size, motor weight, Amps, heat, and flight time. For most of us, turning a bigger prop at a lower RPM with reduced prop stall and higher torque is the ultimate goal. Sometimes this is all about disk diameter and pitch, but the prop constant will also tell us about performance relative to load.

Feel free to PM me if there is a question about my analysis, but feel free to run with the data too, or duplicate the test and present different data, or try new propellers in this size class. This should be fun for some of us, but crazy boring for others. Such is life.

I for one appreciate everything you guys have done and continue to do with these tests. You can never have too much good information, besides it's just interesting stuff.

Originally Posted by frankjp

Oh yes,,James would be like this.


Tom, how about for this test we blindfold you while we switch props,put the plane in the air,hand you the Tx,fly it,land it at the end of the runway,then make your analysis. You need a little pressure too. Oh ya ,we'll pull the blindfold somewhere in there.

Great suggestion Frank, your wisdom is shinning thru.

Tom,

Your the officer in charge of the much anticipated prop flight test so it really is your call on how you wish to pull it off.

Here are my thoughts for your consideration. Frank is spot on with a pilot blind prop test. Double blind would be even better. Two or more pilots blind to what prop they are flying at test time. Each pilot flying each prop twice in a random order with a surveyor wth clipboard standing next to them on the flight line recording their on the fly realtime subjective feel of the props in differing 3D and IMAC manuvers.

Again the props and testing torch has been passed to your capable hands and this is your deal / show now. Whatever you come up with will be absolutely superb. Make us all proud and kick some Kindest Regards, Your fan Speed.

A60-16M(215kv) / CC HV110/ CC Bec Pro / Mejzlik 22X12 e running on 45/90C Nanotec 4500mah 10s 101amps/ 3850 watts@ 7100 Rpms. Great reliable combo with over 250+ flights in a 78" EF Extra 300.

Q80-8M hacker/ opto spin 170 ESC/ Western Robotics 14s Bec/ Mejzlik 24X10 TH or APC 24X12 running on 35/70C 5000mah 12s in Extreme Flight 88" Edge 540. Haven't run the Q80 yet ...but@ up to 5500 watt( 7.3 hp) this should be ballistic power. Way over the DA60/proflow canister power I had in the plane previously. I'll update amps, watts, and rpm# as I get them!

James

Originally Posted by dead

This thread is designed to post data, observations, questions and any other banter that is related to power systems (Motor, ESC/ BEC, Lipo, Prop) for Extreme Flight aircraft.

I have found that every build thread for every different plane as well as the EF owner's thread contains lots of questions, and information that is discussed and re-discussed over and over. This thread is designed to consolidate this valuable information as well as to stream line the many different build threads out there.

HAVE FUN!

Dead, Here is an idea take it for what it is worth. Not sure what thread tools you have as the orginal author of how much effort it would take to maintain.

Image that at the very front of this thread each EF plane discussed has a power system summary. That way anyone curious could look at the first page or so and see what most people are running (Motor, ESC, LIPo, Prop) for a given airplane. It would be kind of a contributor updatable front sort of like a powersystem wikiepedia.

It would look something like this:
60" Edge EXP
Motors - Torque xyz-123 / Motofly abc-456
ESC - Airboss 80A / Castle Ice 100A
LIPO - Nanotech 3300 6S 45/90c / Sky 3600 6S 30/60c
Prop - 15x6 / 15x7 APC E / Xoar PJN

Just trying to take this awesome thread to the next level.
Lee

Originally Posted by Subsonic Ken

The 2820-750 now come wound to about 683Kv

Ken

Really? Cool!

Originally Posted by Subsonic Ken

Tom,
Should only be about 6lbs thrust.

Ken

Hmm... I'll have to re-do my thrust check if I get a chance tomorrow (fish scale test). Thanks for clarifying.

--Tom K.