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Old Nov 04, 2011, 04:59 PM
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central PA.
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Originally Posted by Tom K. View Post
Whether or not it damages it, it stresses it more as the motor tries to overcome inertia. Also, from a performance standpoint, using a gas prop doesn't make any sense as electric props are more efficient, like you said. However, in theory at least, the added weight leads to more inertia the motor has to overcome to turn the prop, adding to possibly higher amps, more heat, shorter flight times, and shorter battery life.

--Tom K.
It's just a prop. People shouldn't neglect heat or load on the system regardless... just like any other prop, you make a choice based on the load you place on the system, and adjust flight times according to how fast you drain the batteries. It's like any other setup, but it doesn't have to create any more stress or load. Gasser props can be part of a very nice and very smooth running system that places no more load on anything then an electric prop. For the same current draw though you can indeed run a larger electric prop and generate more thrust... it's just an efficiency/performance difference.
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Old Nov 04, 2011, 05:24 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
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In other news, the props for the prop analysis came in the mail... so we'll see how the props make out.

--Tom K.
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Old Nov 04, 2011, 05:27 PM
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USA, WA, Redmond
Joined Aug 2010
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Propeller Pondery / Brand Comparison

Ever lie awake at night wondering what is the best propeller brand for a given setup? Is a $14 prop better than a $7? Is there really a performance difference between a wood or composite prop? Can you really tell a difference between a dedicated electric prop vs. a glow prop? Which prop is better for 3D or IMAC? Which prop fly’s better not just tests better? Inquiring minds want to know!

In the coming weeks I will be testing multiple propeller brands both measurably (bench test) and subjectively (flight test). I have also solicited a couple of creditable RC groups contributors to give their insight as well. I wanted to find out just what is the best prop brand for the (60" EXP plane / motor 4016T/500 / esc 80A / batt 6S 3300mah ) combination. Note, I am not getting paid to do this propeller comparison nor was I provided any propellers for free, this will be a straight up test.

Here are the brands I will be testing:
Xoar PJN
Vox
Vess Sport
Falcon
EMP Neodym Scimitar
APC E

Oh yes there will be armchair critics because like anything else part of it comes down to personal preference. However after my testing, if you can prove that you are a legitimate RC contributor, have the skills, background and attention to detail, I will send you the entire prop array for a second test run. A second posted independent test using the same props with the same or different equivalent power set up.

Beware if you derogatorily speak up then get ready to man up (3D/IMAC posers) and do the whole prop test your self. The first potential criticism... how am I qualified to do the test? I am Project Manager for a Seattle based Airplane Mfg...

Sit back and prepare your self for some fun, lively debate and cool results in the coming weeks. So just who is the best prop mfg? We are going to find out.

Lee
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Old Nov 04, 2011, 05:31 PM
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USA, WA, Redmond
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Propeller Pondery / Brand Comparison / Physical Data & Dimensions

Attached is a pic of the propellers tested and spreadsheet with the physical data & dimenisions.

APC Thin-E
EMP Scimitar
Falcon Beechwood
Vess Sport
Vox Electric
Xoar PJN


Notes
-All Propellers were calibrated to a 8mm prop shaft, checked for balance and corrected if needed.
-15x8 Propeller was used for comparison based on best theoretical pitch value (15/2=7.5) and availability from all brands.
- The EMP required the most work to achieve neutral balance.
- The Vox Prop was the lightest of the props weighing in at 31grams.


System Constants
Motor Torque 4016T-500 (Turns 16/ KV 500)
Battery Turnigy nano-tech 3300mah 6S 45~90C Lipo
ESC Airboss 80 Elite (80A)


Attached is a pic of the static test bed and equipment that will be used for testing.
-Test was static with motor system installed on test stand.
-Eflite Wattmeter
-O'Donnell infrared thermometer
-Hanger 9 RPM Meter
-Berkley Digital 50lb capacity Fish Scale
-Thunder Power 610C Lipo Charger


I should have the static bench test results posted in the next couple of weeks. I will be working with Aeroplayin to review and validate the measurable results. In the future Northwest weather permitting I will try to work with Flopgun to perform subjective flight tests for each prop because how a propeller performs in the air is just as important as bench data.

Stay tuned this should get interesting. So just who is the best prop mfg? We are going to find out.
Lee
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Old Nov 04, 2011, 05:35 PM
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USA, WA, Redmond
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Propeller Pondery / Brand Comparison / The Bench Test Results Ta Da!

Just what is the best prop brand for the (60" EXP plane / motor 4016T/500 / esc 80A / batt 6S 3300mah ) combination? You had best be sitting down for the two part collaborative measurable results thread!

I have bench tested the props and generated the initial data. Attached are two results graphs and the full up raw prop data captured. Aeroplayin (Jim) has reviewed the results and will provide some stellar detailed analysis and wisdom which he will release in a forth coming EXP thread.

Limited Conclusions
I took exhaustive efforts to remove as many variables out of the test equation. Talk is cheap results are what really counts. While my test methodology was not perfect it was validated by Aeroplayin as a decent effort with linear results. However I think there is always room for improvement.

What does it all mean? I will save the in depth analysis for Aeroplayin who will blow your socks off. However here are my limited observations and conclusions.

1-Stating just Watts produced is not the end all determinative performance measurement. True Watts will give you a good gauge on a props performance in the power system but you need more info Volts, AMPs, Thrust, RPM, Mah Returned to Batt and Heat Build up to clearly conclude a propellers overall performance and efficiency. For example, you could take a really inefficient prop and it could produce wild WATT numbers but low thrust in a given power system.

2-Who is the best prop mfg? It depends upon what you’re looking for. In this power system experiment, if pitch choice remains a constant, then there’s three options. Clearly if you want raw thrust it’s the wood Vess glow prop. It’s apparent that Vess has really done their aero engineering homework and you can see it in the numbers. If you want longer flight times go with the composite APC prop. If your airplanes on a diet and you want a light weight prop that provides decent flight times and excellent thrust Xoar is your prop.

3-Myth busted! VOX and Xoar are the same just rebranded. If there was one test that rattled me it was the Vox vs Xoar bench test. Xoar was more efficient, period (less Amp draw, similar thrust, higher RPM and lower system temps). It rattled me so much I fully retested the Vox and Xoar to validate the results. While I won’t rule out that VOX may be produced in the same factory as Xoar because the props at first glace are so similar looking. Xoar is definitely shrewdly holding back on some key competitive and proprietary data. Without leveraging mult-million dollar test and measurement equipment at midnight, by eye and my crude measurements it appears that Xoar’s little better airfoil profiling and premium beechwood selection are the separating performance factors.

Now What?

Whoa wait a minute! Bench testing is not enough! How do the flippin props perform in the air? Great question. Leaving no stone unturned, I am going to work with Flopgun to see if he is available, Northwest weather permitting, to do subjective flight testing. If Flopgun is unable to perform flight tests due to weather, then I will be sending the prop array to Tom K and Aeroplayin for further testing including subjective flight testing. Once it is determined which props have most flight potential then we can start tweaking with the pitch.

Stay tuned as this is gonna get crazy interesting. Six props tested one prop wins.

The brands and models measurably tested
-APC Thin-E
-EMP Neodym Scimitar
-Falcon Beechwood
-Vess Sport
-Vox Electric
-Xoar PJN

System Constants
-Motor Torque 4016T-500 (Turns 16/ KV 500)
-Battery Turnigy nano-tech 3300mah 6S 45~90C Lipo
-ESC Airboss 80 Elite (80A)

Notes
-Metric values where used due to more precise measurement.
-All test equipment was calibrated prior to the test and all propellers were tested on the same day.
-All Propellers were calibrated to a 8mm prop shaft, checked for balance and corrected if needed.
-Data was based on the average of three 20sec WOT bursts with alternating 20sec 50% Throttle recovery cycles. 2min total run time.
-15x8 Propeller was used for comparison based on best theoretical pitch value (15/2=7.5) and availability from all brands.
-The same battery was used which was fully charged and starting battery voltage was (25.0 volts) for each prop eval
-Results Data was compared against ecalc web tool (http://www.ecalc.ch/) / Aeroplayin reviewed the data, preformed additional calculations and analysis forth coming.
-Test results will greatly vary based upon motor / esc / batt / test equipment used. Example (Lower Batt Mah / C values will yield lower Amps / Watts / Thrust)
-I didn’t get paid to do this propeller comparison nor was I provided any propellers for free, this was straight up no hidden agenda test.

I wish to again thank Aeroplayin for all his efforts and thank EXP contributors for sharing their knowledge. My hope is that this prop test thread has cultivated interest, that our joint RC Group efforts can help set a new propeller testing bench mark and we can continue to contribute to the EXP thread collaborative knowledge base. Thus making the EXP’s the absolute pinnacle of flight performers. I certainly have learned a lot from this experiment and I have had a lot of fun playing the mad scientist.

Kindest Regards,
Lee

“If you’re not dragging your rudder on the ground your not flying low enough.”
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Old Nov 04, 2011, 05:37 PM
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USA, WA, Redmond
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Propeller Pondery / Lipo Parameter Effects / One Change...Changes Everthing

I was curious what the effects would be if I only changed Lipo's in the power system. This test run keeps the prop constant (Brand, Dia and Pitch), the Lipo constant at 6s and changes with the C value (30/60C & 45/90C) and Mah (3300 & 4000).

The data/results are attached below. What becomes obvious is the fact that if you change the lipo parameters or pretty much any component in the power system for that matter it changes everything regarding the measurable results.

To the 3D sinsei's this is no news. To the rest of us it means we should carry a wattmeter in our flight box at all times. Change props remeasure the amps prior to flight, Change Lipo C or Mah remeasure the amps prior to flight, Changed your underwear, well then try flyin a little further off the deck bozo.

Next in the Lab: Pitch and Diameter experiments showing the effects on the system. Caution, Ahh Houston we have a problem... 20X12 prop!!!

Then the much anticipated finally! Subjective Flight Testing of the prop array.

I have made an executive call. Northwest weather is too unpredictable to assure near future subjective flight tests of the prop array. I personally would like to see the results sooner than later. I am passing the testing torch and prop array to Aeroplayin and Tom K. for more testing and the ever important, much anticipated flight testing in better weather Florida. The test props and the final results will be in great hands as they have demonstrated they have the skills to pay the bills.

Six props tested one prop wins!
Who's it gonna be APC, VESS, XOAR

Lee
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Old Nov 04, 2011, 05:43 PM
They Call him Dead!
YellowJacketsRC's Avatar
United States, SC, Pawleys Island
Joined Jul 2003
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http://rcwebclub.com/LinkClick.aspx?...%3d&tabid=1208

This is the Analysis to go along with Leespaddock's testing...
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Old Nov 04, 2011, 05:45 PM
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USA, WA, Redmond
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Quote:
Originally Posted by Tom K. View Post
In other news, the props for the prop analysis came in the mail... so we'll see how the props make out.

--Tom K.
Knock em dead Tom.

Whoo Hoo! Hoo Rah!

Love this new thread. It's like a brand new playground dibs on the monkey bars

The propeller forecast. Showers of falling ego's with cloud breaks of paradigm shifting in-lighten-ment. lol
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Last edited by leespaddock; Nov 04, 2011 at 09:03 PM.
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Old Nov 04, 2011, 07:21 PM
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Burke, VA
Joined Sep 2009
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Good move Dead, this is perfect for some really useful info concentrated in one nice thread.
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Old Nov 04, 2011, 07:51 PM
2.3 D Hack Bradenton FL
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Joined Dec 2010
182 Posts
Quote:
Originally Posted by leespaddock View Post
Knock em dead Tom.

Whoo Hoo! Hoo Rah!

Love this new thread. It's like a brand new playground free of pesky data bullies!

The propeller forecast. Showers of falling ego's with cloud breaks of paradigm shifting in-lighten-ment. lol
I AM GLUED TO THIS ONE !!!!! I weigh wheel collars
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Old Nov 04, 2011, 08:57 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
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Quote:
Originally Posted by leespaddock View Post
Ever lie awake at night wondering what is the best propeller brand for a given setup?

Well I am married so I tend to lie awake at night wondering about a lot of stuff.
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Old Nov 04, 2011, 09:13 PM
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leespaddock's Avatar
USA, WA, Redmond
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Originally Posted by stgdz View Post
Well I am married so I tend to lie awake at night wondering about a lot of stuff.
I am married too. My wife loves me but thinks I am a bit crazy. Airplane crazy that is. Bad-dump-bump.
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Old Nov 04, 2011, 09:23 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
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Quote:
Originally Posted by frankjp View Post
I AM GLUED TO THIS ONE !!!!! I weigh wheel collars
Haha
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Latest blog entry: 12S on the 3DHS 74" Edge 540
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Old Nov 04, 2011, 09:34 PM
JUNK RADIO
Flazo's Avatar
USA, NY, Queens
Joined Dec 2006
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this is very technical! : ) Tim where are you? : )

fred
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Old Nov 04, 2011, 09:36 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
3,585 Posts
Whoa! Did RCG just change their format? Like... dramitically? I'm using fluid beta and it just became really weird!

--Tom K.
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