Alfa Fan motor and power testing :D - Page 5 - RC Groups
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Nov 02, 2005, 08:46 PM
Suspended Account

Well said. And to all the naysayers, just remember, Nobody ever built a statue to a critic. Keep on pushing the limit Justin. If it wasn't for people like you who are willing to take a few risks, we'd still be limping through the sky with speed 480's and 600 AR NiCads.

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Nov 02, 2005, 08:54 PM
Model Designer
keven64's Avatar
rcguy01 said
Ok, once upon a time, in America, when the sky was so blue
and the bed was so warm, so good for ****
No idea what that has to do with any of this...

and added
only if you used those motors within their specs.
Not true - as my Feigao example above illustrates completely !

Specifications are an odd thing - and odd that you should mention Mega motors...

A Mega 16/15/2 motor is rated at around 35A max.
That IS odd... as many modellers run them at 33% over specification - for many, many flights.
( note I did not say thousands - or years... )

rcguy01 ( no idea what your REAL name is... ), I am not saying you're WRONG... I was merely pointing out that there are TWO sides to every story...
The Mega motors are another example that well illustrates that.

If you run any brushless motor at the specified power levels, you will, ( like me *) have YEARS of service - as you have discovered for yourself.

If however, you are willing to push just a little bit, you may just find 'something else'... with no apparant detrimental effect to the motor...

The point that Barry touched upon - about things lasting is a good one... but with quality getting better, and prices getting lower, we can all afford to be a little wreckless...

( Oh - and by the way... you DID type YEARS... )

* I've been flying a Hacker B20-26L in '400' models for YEARS !
I mean YEARS, too. I bought it for Christmas in 2001 - from Gordon Tarling.
I telephoned - and asked him for a brushless that would be a 'straight swap' for a Speed400 motor.
The £80 that that motor cost back then was money well-spent in my opinion...

With a Gunther on 8-cell Kan1050 battery packs it has about 140% of the power of a speed400 - at only 70% of the current !

Nov 02, 2005, 09:01 PM
smug in granny panties
monkamarm2000's Avatar
I would but im busy thrashing brand new stuff! lol

Nov 02, 2005, 09:01 PM
Watts your motivation
roccobro's Avatar
I post pictures because some like to "speak from their backsides" when it comes to setups they have used "successfully" for whatever reason. AGAIN- PLEASE of you have nothing POSITIVE or CONSTRUCTIVE, stay out of my thread!!!!! Many posts, not a single shred of importance. Gooneybird/E_flyer2005/John-flyer/RCGuy01 I am talking to you, stop trolling here! Obivously you don't understand why WE fly EDF, but we don't bother you do we?

Back on topic again, It was a slow day today. The Himax setup was still on the chopping block so I made another adapter to make a 5s2p TP 1900. Still letting the motor cool down while I try to get my screen capture working again. Suffice to say, it was interesting, but not any faster than any previously tested Mega setup. And it had a funny smell afterwards.

If pounding these tests out, each for minutes not seconds ata time, isn't enough torture then I don't know what is.

What is a "stress test"? Eric, you offerend to have a rotor tested for strength through excessive forces, can I send you one? I really don't care how one of these rotors will hold up to repeated 70K spins (done quite a few already), but if that is a "stress test".....

Nov 02, 2005, 09:07 PM
Watts your motivation
roccobro's Avatar
Power- Thanks for the link. I thinkthe motors will hold up fine until they fail. If/when the bearings need to come out, I will take some measurements and find good replacements.

Randy- Thanks for popping in. Thanks for the motors, I LOVE them!!! I saw a deal on a MIG the other day, had to pass for now. I build fast, but am veeery slow to maiden.

Bruce- There are only two difference between the Mk1 and Mk2 fans, one is the ID of the fan shroud (Mk1 is .5mm smaller) and the other is the rotor (same look very different molds and blade designs. For the Mega to fit, you have to do some grinding, but nothing as schnazzy or conprehensive as power did to the Microfan. Basically, as you look at the rear of the fan unit motor tube, there is a little lip that aids in centering the smaller motors. If you grind that off and continue that diam to the front, the Mega slides in. I first thought the (factory?) machining took alot of material out, but after going back in with my dremel and sanding drum, there is alot of material left and not as much removed as I first thought.

I use the Mk2 rotor as is has more blade area and actually creates acceptable loads and air movement. I would suspect you would have to spin 70K to make even what the 4200 does on 3s (42k rpm). An interesting note- the Mk1 rotor had a little better centering and tightness (blade gap AND rotor "button" tension) built in. the Mk2 rotor has a countersunk chattering machine mark where the rotor hold down screw goes. Two of my many rotors actually had teh hole offset some.

Nov 02, 2005, 09:09 PM
EDF rules... :)
AirX's Avatar
Yah, send me one of them and I will get the blades pulled off it to test the calculations for the rotor that I did. Pm on the way.

Eric B.
Nov 02, 2005, 09:41 PM
Suspended Account
Originally Posted by rcguy01
I would love to try the time honor systems, and not
some initial tests out of few seconds on the bench.
What Justin is doing is far superior to the "time honor systems" of just stuffing it in an airplane and flying it until it fails and trying to figure out what went wrong post-mortem. He's built a test rig and is taking ACTUAL MEASUREMENTS of all parameters, voltage, current, power, thrust, and TEMPERATURE.

Heat is the culprit that demagnetizes the rotors and causes the batteries and electronics to fail. Justin is proceeding with a disciplined engineering approach to determine the feasibility of even operating an Alpha fan at these power levels before proceeding to an actual flight test.

I am speaking as a systems engineer and program manager with 20 years of experience managing major weapons systems acquistions for the Air Force. My experience includes 3 years at General Electric Aircraft Engines. He's doing it just like the "big boys".

Justin has chosen to share his test results with the community here as he makes progress, no different from a build thread. So, why don't you let him complete his testing before you start throwing rocks at him and saying "it won't last" with NO DATA to support your claim. Or are you working some other agenda here?

Nov 02, 2005, 09:42 PM
Watts your motivation
roccobro's Avatar
Thanks Rob. Both equipment and the tester are just simple items in this fun testing.

Jim- I did not forgot your question. As far as switching speed of the controllers, I am no expert and am not at the top of my game today. The only time I hit the "limit" of a controller was with a P-10 (12.500 hz limit) and a "HOT" CD motor in an EDF-50. Once it got past ~52k rpm it would cut out. Now, the cd motor was 9 stator, 6 mags- is that 3.5 commutations per revolution-each comm is 2 switches ( I'm pretty sure I'm wrong here)? Anyways, the Mega has less commutations (6mags x ?windings) per rev, and the P-35 and 45 are rated higher with programmability for 11, 22 and 41 Khz. Alot of head room in that respect. I am running my P-45 with factory settings for all these tests.

Nov 02, 2005, 10:41 PM
Watts your motivation
roccobro's Avatar
Originally Posted by Paul DF jet man
HA HA HA that is absolutely stupid , running an Alfa 60 on 550+ watts. What were you thinking??????

AND thatís why I love it LOL . You did your self proud mate in my eyes anyway.

I love pushing the limits well beyond the specs and finding out something new. WHY because we can .

For the nay sayerís say what ever u want where having fun and where not using your equipment so I see no reason why anyone should criticize these tests.

RIDE ON roccobro I look forward to more of your amazing resalts.

I have 4 spare Alfa MK2 fans 2 with 2025 4200ís and 2 with 2025 5300 I will have a play with these later on when I have time.

Maybe the 5300 on 4s.

Thanks Paul. You know, I have to blame you for this whole Alfa testing kick! After one user said that there is nothing better than a himax 5300 on 3s, I knew that generality to be false. So far, the 4200 seems to be more efficient, a better "bang for the buck", and cheaper for a "starter" setup than the 5300 on 3s! If I had a 5300, I'd try it on 4s for you. The 4200 on 5s (like in your bad @** SR-71) did right what you said it would. I should have started that test with a heatsink.

If screen capture is still non-op in a couple hours, I'll just post the next set of useless information I have. Tomorrow should be back to the Megas, the 16/7/4 on 4s with inlet, and maybe the /5 on 4s(5s too?) to compare. Don't want to offend anybody's decency with more 500+watts runs in this 60mm fan!!!


EDIT: Had to remove some smilies from Paul's and my post for RCG use! : ) Did not know there was a limit! : p
Nov 02, 2005, 10:59 PM
Suspended Account
Speed is Life's Avatar
You GO rocco'............

I've just settled on my next EDF project:
Alfa fan reamed out to fit a Mega /2 installed in an EDF Gooneybird. (hey, maybe an original design!)
In prep for flight I think I'll chase the cat down the HALL imitating machinegun sounds. WOO hoo!!!!!

rcguy01, can you give me a recommend for a good, long lasting, eco-friendly ESC/battery combo? Do you think used LiPo's would work? 3s or 4s?

This setup has to last for YEARS.................
Nov 02, 2005, 11:24 PM
SoCal, Year Round Flying!
bmiller's Avatar
It's cool to test and find out how much you can push the equipment, but we all still need to be based in reality. I mean yeah now we know it's possible to get 500+ watts out of the alfa 60mm (Much thanks to Justin!)but how much weight/battery are you going to have to put in your model jet to deal with 40+amps. Then we'll have to fiberglass it/bigger spars/heavier high torque servos to deal w/ the speed, not to mention the magnets coming loose/bearings seizing in the poor motor and thats if the rotor doesn't explode first! And by the time we do all this we'll need to put a bigger fan in the thing in the first place!
Last edited by bmiller; Nov 02, 2005 at 11:43 PM. Reason: don't want to sound like I'm mad at anybody
Nov 02, 2005, 11:30 PM
SoCal, Year Round Flying!
bmiller's Avatar
Hi Justin,
You posted the answers to my questions as I was typing . Thank you!

btw I have a 2025/5300 I could lend you if you want to test w/it
(And I won't hold you responsible if it explodes!)
Last edited by bmiller; Nov 02, 2005 at 11:36 PM.
Nov 02, 2005, 11:41 PM
Paul DF jet man's Avatar
Originally Posted by roccobro
Thanks Paul. You know, I have to blame you for this whole Alfa testing kick! After one user said that there is nothing better than a himax 5300 on 3s, I knew that generality to be false. So far, the 4200 seems to be more efficient, a better "bang for the buck", and cheaper for a "starter" setup than the 5300 on 3s! If I had a 5300, I'd try it on 4s for you. The 4200 on 5s (like in your bad @** SR-71) did right what you said it would. I should have started that test with a heatsink.

All becouse of me NO...... .......... really LOL

im glad you had sucsess just like i did with the 4200 on 5s its a good combo the only draw back would have to be the need for a seperate BEC pack

i will try the 5300 i have her on 4s when my F-86 arrives.
Nov 03, 2005, 02:45 AM
Watts your motivation
roccobro's Avatar
Bruce, thanks for the offer. I think if you are to go up in V, you should step down in Kv. The efficiency falls off real fast with high Kv and high v . Kinda like Nitrous in a vehicle. HUGE temporary grins, but not long lasting performance. There are a bunch of you Alfa owners with an installed 5300 fan that could try a 4s pack and give a nose down comparison for others to get foamy at the mouth. I'm curious to find out how the Alfa ducting does at these flow rates.... :evil grin:

The ParkBEC is a great item. Under $20 and only weighs a few grams and can supply 5v (or 6v), for four micro servos or 5 big ones. Some of the 4s setups are well worth the extra weight an additional 46g TP PL 2100 cell would add, adn they are rated for 50amp bursts.... WOOHOO!

Snagit screencapture has hit a permanent snag. I'll post numbers later...

Nov 03, 2005, 06:22 AM
Model Designer
keven64's Avatar

Snagit has snagged ?

Copy the whole folder from where it was installed, and paste it to a new folder. ( Forget about installing it again... )

Then create a new shortcut to the new position, and delete the original. That ought to sort it...

If not...


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