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Old Feb 24, 2008, 11:47 AM
Plane and multirotor's - FPV
DrEvil's Avatar
Moss, Norway
Joined Jun 2007
855 Posts
Hi there dave
I am quite a newbee , so speed is not the issue, but desent scale speed and , most of all plenty thrust is important.
Will a 9" give me thrust to spare ??
This 10x10" is a APC-E , i also have a 10x8,5 4blade noname, butt i guess it works best on the ground
Thanks for the quick reply...

Kai

' And up she goes '
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Old Feb 24, 2008, 11:55 AM
Dave North
timocharis's Avatar
USA, CA, San Jose
Joined Apr 2004
5,254 Posts
Try the 1170 to begin with and adjust from there. It's a very thrusty prop. The 1080 is an okay choice if you think the 1170 is too slow... or maybe the 10x6 or 10x8 APC.


Dave
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Old Feb 24, 2008, 12:24 PM
Plane and multirotor's - FPV
DrEvil's Avatar
Moss, Norway
Joined Jun 2007
855 Posts
Dave

Ok, i will do a Amp. draw mesure later this evening with the 11x7GWS.
I want to ceep it its most effectiv range.
But do you think a 10x10 is too much for the motor, or does it get inneffectiv ?
Sorry about my English...Not perfect
How about 4cell, will it be able to run a 9" or a 10" ??
I have several 2cell i can conect in series.

Thanks... Kai
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Old Feb 25, 2008, 08:11 PM
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shawn595's Avatar
United States, VA, Bedford
Joined Sep 2006
2,018 Posts
The wire I got from Dave just showed up my mailbox today but before I rewind I did a little testing first to get a baseline.

Here's my result:

GWS 10x6 HD; Loong Max 3S 1300 battery; 18T Delta 22 awg dLRK

7050 rpm: 9.46 amps, 10.5 volts; 634grams/22.36 ounces thrust

Note that my efficiency numbers are calculated, not measured and I can't give an effeciency result because Badcock won't calculate them.

RPM was measured using a Tower Hobbies Digital Mini-Tach and amps and volts were measured using a Watt's Up meter. The test was run twice indoors and an LED flashlight was suspended in front of the prop while the tach took a reading from behind the prop. The ESC is a Turnigy Plush 18.

Interpret these results as you see fit and make suggestions as necessary. I'm very green to testing motors and would rather be notified of a flaw in my setup than provide incorrect numbers. (Note picture of testing setup below.)

-Shawn
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Old Feb 25, 2008, 08:39 PM
Dave North
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USA, CA, San Jose
Joined Apr 2004
5,254 Posts
Drive Calculator will give an efficiency/thrust reading for the 1060. It says you just got:

25.18oz thrust @ 82.4% efficiency. I find DC to be just a hair optimistic on thrust and therefore a hair optimistic on efficiency. But not a whole lot, and sometimes it hits the ball cleanly. Badcock tends to be a bit low on the 1060, probably because of using older Dr Kiwi prop data.


Dave
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Old Feb 26, 2008, 08:01 AM
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United States, VA, Bedford
Joined Sep 2006
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Thanks for the info Dave. Sounds like my numbers are realistic enough so that means I have enough of a baseline to compare my rewind too.

I'll look at Drive Calculator too. It'll be nice to have something to compare Badcock to.

-Shawn
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Old Feb 28, 2008, 12:09 AM
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manuel v's Avatar
Mexico, BC, Mexicali
Joined Aug 2004
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Finally came my BW with steroid HXT DT750. and now need 21 or 20 AWG
I am doing a little EP foamy for the. But I leaving something this big. So I think that would put 2 engines together in tandem.

Manuel V.
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Old Feb 28, 2008, 11:14 AM
Dave North
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USA, CA, San Jose
Joined Apr 2004
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Manuel, mui macho! Carramba!


Dave
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Old Feb 29, 2008, 11:04 PM
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USA, CA, San Carlos
Joined Nov 2007
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Manuel, what's the plane on the bottom left w/ the blue cockpit? Looks spiffy and I'd like to make one : ]

- Jeff
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Old Mar 01, 2008, 12:52 AM
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manuel v's Avatar
Mexico, BC, Mexicali
Joined Aug 2004
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Jkarnacki.

The plane is a Skeeter with flat wing of EP foam 1/2 inch.
9 oz. with Blue wonder Kit 17T Star and 3s 500ma. GWS 9x5.

http://www.rcgroups.com/forums/showthread.php?t=797010

original plane: with plans.
http://www.rcgroups.com/forums/showthread.php?t=360600

Manuel V.
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Old Mar 01, 2008, 12:17 PM
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United States, VA, Bedford
Joined Sep 2006
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18T of 21 awg

I finally got the 18T of 21 wound up and tested. This definitely isn't my prettiest wind but it does run and the results are.. well.. judge for yourself:

GWS 10x6 HD; Hextronic D9 3S 1300 battery; 18T Delta 21 awg dLRK
7260 rpm: 9.8 amps, 10.6 volts

So there's an extra 200 rpm with about half an amp and 1/10th of a volt increase. It would have been more interesting to run this test again with the same Loong Max battery I used in the first test but unfortunately that battery is no longer with us. Anyway, using Drive Calculator's Simple Prop Calculator I came up with 758 grams of thrust (26.73 ounces) with an efficiency of 85.3. This mimics the slight improvement that was shown by Dave's calculated numbers below.

So it's only slightly better than the 18T of 22 and honsetly I'm not so sure it's worth the extra trouble. 18T of 22 is a easy wind. Almost too easy really. And the difference between 22awg and 21 awg with regard to amount of effort to wind it is amazing. You just don't get this difference in workabilty between the smaller gauges in only one step up. So I'll leave it up to you to decide if it's worth the extra effort. It would be really hard to justify the extra effort using the numbers shown above.

-Shawn
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Old Mar 01, 2008, 12:49 PM
Dave North
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USA, CA, San Jose
Joined Apr 2004
5,254 Posts
First let me say that's a Kick Grass wind without any Gr needed. Exactly how a packed wind should look -- the best motors almost never look perfect because you have to tickle the wire a little bit for a full fit. (Compare to "am I awake yet" 22g wind...)

What's with that chip? Did I sell you some crap wire?

Love the result. It's so close to what I saw with the 22g that I'm darned glad I gave up on the motor when I did. My opinion? Definitely not worth it. I know what you just went through, and it's a great experience. You should be proud of yourself! But with my clacky hardware (I got a bum motor! The dirty rats) I'm certain I'd have been getting nowhere. Thanks for confirming.

That motor makes no sense to me at all. Manuel nailed it cold: wind it with anything, give it the right watts in, and it will pull a tugboat.

At any rate, I think that's a beautiful job.


Dave
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Old Mar 01, 2008, 01:37 PM
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United States, VA, Bedford
Joined Sep 2006
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Dave,

Thanks for the compliments! It was definitely one of my toughest winds and there's no doubt that it took the longest. Still, it's done and my fingers are happy for the rest.

I chipped that wire myself. I have the standard dLRK pattern committed to (muscle) memory but still don't have the Delta variant fully memorized yet. As you can guess, I wound two teeth using the standard version and had to unwind and rewind them to get the correct result. That's probably where the chip make from. Needless to say, I'm happy it even runs because if that chip had been anywhere else it could have been a show stopper.

Oh, I appreciate the deal you gave me with the wire. I'd still be waiting another week and or more for it to arrive from AllTronics. Those extra wing saddles are comforting to have in the hobby box too.

This motor is certainly a conundrum. It's efficient as is but refuses to show any improvements. Whether that's comforting or frustrating defends on your point of view but I'm currently going with the latter. That'll probably change after a flight or two with it though..

I do have some GWS 11x7 *D props on the way and I'll give them a go when they arrive. I don't expect any miracles but it'll be interesting to see how it compares with the 10x6. I don't really need any more power so I may just settle for using the 10x6 and going with a 3S 800 mah lipo. Half power (crusing speed) requires approx 4 amps so that's certainly not out of the question on a calm day.

-Shawn
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Old Mar 01, 2008, 03:59 PM
Dave North
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USA, CA, San Jose
Joined Apr 2004
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Basically I found it frustrating too. Join the club! I do think the 800 3S sounds like the way to go....


Dave
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Old Mar 01, 2008, 06:51 PM
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manuel v's Avatar
Mexico, BC, Mexicali
Joined Aug 2004
5,180 Posts
Shawn

Very neat winding. paint the chip with nail paint.
Today, i wind a 17T 21awg. horrible wind but its working.

No load, 9200 rpm, 11.40V, 1.4A. 3s 900ma. KV 807.

GWS 10x6, 7300rpm, 10.8V, 10.9A, 3s1600.
GWS 10x6, 7600rpm, 11.4V, 12A, 3s1300

APC 10x7, 7500rpm, 11.72v, 14.3A, 3s 2250
APC 12x6, 7100 rpm, 11.44V, 18.3A, 3s 2250, 47 oz, 83.5%

Im very happy. with this motor,
Is very cheap remplace for E-flite 480-920 and only with 209 Watts,

Manuel V.
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