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Old May 11, 2011, 09:18 PM
Got the Slickness
gabrielisrael's Avatar
Seattle, WA
Joined Jul 2010
2,521 Posts
Maidened my new 3DHS version 3 SHP (Blue scheme with SFG's) last night and flew the 30cc MXS and the Adrenalin P-51 Voodoo proto-type plane.

The V3 SHP is even better than my original yellow one... a real harrier monster!

Sorry, I didnt get any photos - too busy having fun flying

Lets plan on flying at MARC on Friday afternoon if the weather permits....
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Old May 11, 2011, 09:46 PM
Quadrophenia
egaus's Avatar
Seattle
Joined Mar 2009
915 Posts
I'm down for Friday, got the day off!
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Old May 12, 2011, 12:17 AM
I think I forgot how to fly RC
cryhavoc38's Avatar
United States, WA, Woodinville
Joined Mar 2007
8,063 Posts
Quote:
Originally Posted by egaus View Post
I'm down for Friday, got the day off!
bring ez ups and umbrella's

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Old May 12, 2011, 04:20 AM
Training to be a cage fighter.
bicyclechris's Avatar
Woodinville, WA
Joined Apr 2010
499 Posts
I'm stuck

Man, I have been pondering over the whole issue of what motor to use on 6 cells with my 71" Slick...

After searching through the threads, it seems that everyone is in agreement that on 6 cells a 400-450 gram 380kv motor with a 18"-19" prop is the best overall setup for this plane.

The problem is, 19x10E props on a 380kv motor draws anywhere from 80-90amps.
This exceeds most "recommended" ratings for most motors of this size on the market.

The Hacker A50-16s would fit the bill, but they only rate their maximum amp range at 55 amps.

Many say that Hacker motors are way under-rated, but 55 amps is very far from 90 amps.

The Scorpion 4035-380 motor pulls about 90 amps, although it is only rated to 70 amps continuous.

I believe the Infinite 4035-360kv motor draws around 80 amps with a 19x10E, but I wonder if the lower kv would have decent enough thrust.

The 3D guys are saying that 310kv motors are great for 8 cells, and that 380kv motors are best for 6 cells.

They also say that 350-ish kv motors are a wierd in-between winding, too much for 6s and not enough for 8s.

The new motors that the "cool kids on the block" are now using are the Motrofly 4325 series.
They offer a 380kv version which folks rave about, but on paper it seems the same as the Scorpion 4035-380.

Motrofly doesn't list anything more than bare-basic specs.
They list size and weight dimensions, but no detailed power or amp ratings.
They list data from a couple of props, give some weight recommendations, and that's it.
Their motor construction also looks kind of cheesy, it reminds me of RCSmart motors from ye olde days of yore.

Motrofly:


RCSmart:



Call me shallow, but I'd rather use a Scorpion or Infinite motor based on my first impressions of the Motrofly motors.

Both Infinite and Scorpion are much more thorough in listing power data in physical specs than Motrofly does...

I'm still undecided, but leaning toward a Scorpion motor.

If anyone has found information regarding Hacker, Infinite, Scorpion, Motrofly motors 400-450grams on 6 cells with 19x10E props please share it.

I think if I get a Motrofly motor I'll have to dress cool too:

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Old May 12, 2011, 05:41 AM
aka JetMan Joe
MCSGUY's Avatar
Joined Feb 2010
2,740 Posts
Motor Tests

Here's my results from testing 8 motors trying to answer the same question. The problem is, according to Scorpion (as told by Vitter) this size motor with 6 cells is only rated for 20cc equivalency. Vitter and I both separated the stator core on our Scorpion 4035-380's last week either due to extreme overloading or factory flaw (mine during it's first flight). They say their 5525-225kv on 8 cells is the correct setup for 30cc.

However, the facts in my case are that I ran an Infinite 4035-360 in the same set up (except 19x8 instead of 19x10) for the entire last season with no problem and I got it hot enough a couple times to scorch the windings. Yet my test data shows it's still fully capable. I've also been running the heck out of the Hyperion ZS4035-10 (354kv) I replaced the Scorpion with and have had no trouble whatsoever even though I upsized to a 20x10 prop (and even let Vitter fly it once ;-)

IMHO if the motor frame and bearing support structure will not twist and distort under the type of punishment you dish out (which is what I think caused the Scorpion problem) then if you don't burn it up your OK. I know I overload mine but if it lasts a season or two and is powerful enough to pull me up out of my always bungled hover's- then I'm satisfied. That's certainly not the way I specify industrial servo's out at Boeing but I'm not looking for a 24/7 service factor.

Anyway, that's my two cents on the subject which might be what it's worth. As far as my testing, I ran the motors flat out for 1 minute and evaluated temperature rise to form an opinion as to whether they would survive my kind of throttle management. The other thing I was looking for was max net thrust (subtracting motor weight). There's more detail about the test procedure on my blog.

Joe
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Old May 12, 2011, 10:02 AM
Registered User
Renton, Wa.
Joined Feb 2006
1,758 Posts
Quote:
Originally Posted by bicyclechris View Post
Man, I have been pondering over the whole issue of what motor to use on 6 cells with my 71" Slick...

After searching through the threads, it seems that everyone is in agreement that on 6 cells a 400-450 gram 380kv motor with a 18"-19" prop is the best overall setup for this plane.

The problem is, 19x10E props on a 380kv motor draws anywhere from 80-90amps.
This exceeds most "recommended" ratings for most motors of this size on the market.

The Hacker A50-16s would fit the bill, but they only rate their maximum amp range at 55 amps.

Many say that Hacker motors are way under-rated, but 55 amps is very far from 90 amps.

The Scorpion 4035-380 motor pulls about 90 amps, although it is only rated to 70 amps continuous.

I believe the Infinite 4035-360kv motor draws around 80 amps with a 19x10E, but I wonder if the lower kv would have decent enough thrust.

The 3D guys are saying that 310kv motors are great for 8 cells, and that 380kv motors are best for 6 cells.

They also say that 350-ish kv motors are a wierd in-between winding, too much for 6s and not enough for 8s.

The new motors that the "cool kids on the block" are now using are the Motrofly 4325 series.
They offer a 380kv version which folks rave about, but on paper it seems the same as the Scorpion 4035-380.

Motrofly doesn't list anything more than bare-basic specs.
They list size and weight dimensions, but no detailed power or amp ratings.
They list data from a couple of props, give some weight recommendations, and that's it.
Their motor construction also looks kind of cheesy, it reminds me of RCSmart motors from ye olde days of yore.

Motrofly:


RCSmart:



Call me shallow, but I'd rather use a Scorpion or Infinite motor based on my first impressions of the Motrofly motors.

Both Infinite and Scorpion are much more thorough in listing power data in physical specs than Motrofly does...

I'm still undecided, but leaning toward a Scorpion motor.

If anyone has found information regarding Hacker, Infinite, Scorpion, Motrofly motors 400-450grams on 6 cells with 19x10E props please share it.

I think if I get a Motrofly motor I'll have to dress cool too:


Try e-mailing Ken at subsonicplanes.com for specific numbers on the Motrolfly, he usually responds quite quickly. I'm using the 4325-310 on 8cell in the 72" Extra and I've flown it pretty tamely so far but it has'nt even gotten warm after several flights in a row. Hope that helps.
Steve
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Old May 12, 2011, 10:48 AM
Got the Slickness
gabrielisrael's Avatar
Seattle, WA
Joined Jul 2010
2,521 Posts
Motrofly motors are spoken highly of through the threads.

Check with Ken, I believe that size motor is out of stock for about another 2 to 4 weeks.
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Old May 12, 2011, 11:22 AM
Registered User
Renton, Wa.
Joined Feb 2006
1,758 Posts
Heres some numbers pulled from the 71" Slick thread

I just got my Motrolfly motor back and I wanted to do a static test on my Watts up meter. I recall checking my Slick on another Watt meter when I built it and I can't remember the numbers I got.

Do these look about right?

Motrolfly 4325 380
Xoar 19x10
Turnigy 6S 5000mah 30C

Watts 1974
Amps 88


I recall pulling more amps with the same battery/setup back in January.
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Old May 12, 2011, 11:48 AM
Gonna need a bigger plane . .
FlopGun's Avatar
Kitsap County, WA, USA
Joined Jul 2007
2,951 Posts
Steve, that looks pretty good. The clown had the 380kv scorpion, and was pulling 83-85 with 25C packs with the same prop.

The clown never had any problem with the Scorpion motor, but it is at the limit so I imagine after enough flights it would break down.

2000 watts is about perfect on one of the 70" planes imho.

That new Slick is a little bigger than the old one, but it's shorter right? and a little lighter?
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Old May 12, 2011, 11:57 AM
Registered User
Renton, Wa.
Joined Feb 2006
1,758 Posts
I should have specified this John. I don't have the Slick, I just did a search in the 71" thread for Motrolfly and pulled those numbers out of it. I'm running the Motrolfly 310 in my Extra on 8s, can't remember the numbers off the top of my head but the watts were higher and amps were lower. Amps were in the 70's range and watts 2000 plus range if I recall. Plus I won't deal with a collett adaptor if I don't have to. BTW, one more day to wait LOL. Problem is I'm off tomorrow so probably won't bring the 60" home until Monday, then I leave Wed. for Ia. so I probably won't even start the build until I get back. At least I know it'll be there waiting.
Steve
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Old May 12, 2011, 12:33 PM
I think I forgot how to fly RC
cryhavoc38's Avatar
United States, WA, Woodinville
Joined Mar 2007
8,063 Posts
My take on the amps issue is that the average 3d flyer is not wot all that much so the max amps would be burst only. While im not a fan of hacker motors per se, alot of slickers are using them. The motrolfly is also pretty popular. If the motrolfly is out of stock then I would use the scorp. But..the end user has to be ok with collet adapters unless you use the 5x series with the screw on nuts.

Don't worry too much about max amps unless the motor is used on a warbird wot all the time.
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Old May 12, 2011, 01:08 PM
Registered User
Renton, Wa.
Joined Feb 2006
1,758 Posts
Good point. I rarely use full throttle.
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Old May 12, 2011, 01:17 PM
Quadrophenia
egaus's Avatar
Seattle
Joined Mar 2009
915 Posts
Motor is seeing same amps at WOT or not.

e
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Old May 12, 2011, 01:23 PM
I think I forgot how to fly RC
cryhavoc38's Avatar
United States, WA, Woodinville
Joined Mar 2007
8,063 Posts
Quote:
Originally Posted by egaus View Post
Motor is seeing same amps at WOT or not.

e
thats a whole topic that has troubled me regardless of how many times others have explained it.
I'm an electronics engineer by training, and a server/network engineer by trade, but even with this background, and the fact that our common esc/brushless motors and battery/prop combinations do not learn amperage and wattage, I still and reticent to believe that a motor sees max amperage regardless of throttle settings.

call me stubborn. and it wouldn't surprise me if I've been wrong all this time.
All I know is the practical applications that I have used, versus the theoretical.

lol
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Old May 12, 2011, 01:33 PM
Quadrophenia
egaus's Avatar
Seattle
Joined Mar 2009
915 Posts
My understanding is that the ESC delivers as much amps as the engine wants, determined by its Kv, but the ESC pulses the power to lower the load it delivers. ESC will get hotter at lower throttle as they are working harder there. Motors will get hotter at WOT and fail faster at sustained WOT because there is relatively no pulsing going on at WOT.

This has been my understanding and from what I've read from Lucien to Vitter recently, I believe it is correct. It was explained to me that what you see in your amp/watt meter is just an average of the amps due to the pulsing. Some serious pulsing going on at 8k/sec. This topic is troubling to understand and interpret correctly. I don't think my understanding is 100% and would welcome any one else to contribute.

I think all manufacturers underrate their motors so they don't have to deal with as many unsatisfied customers w/ burnt/broken motors.

e
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