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Old Jan 24, 2013, 11:18 PM
olllian
olllian's Avatar
United States, AZ, Chandler
Joined Nov 2011
608 Posts
Quote:
Originally Posted by jstoll View Post
I put on an APC 8X8 and am running 4S 2200 45-90c nano techs. I really wanted to get out this weekend but its supposed to rain all weekend :-(
I cant find my inductive amp meter and need to buy a watt meter but was wondering if anyone knew what a stock motor pulls with an 8X8 on 4S?
I have much larger speed controllers with separate BECs if I need it....but I ended up gluing the wing on after the crash on the maiden so Ill have to cut out the old speed controller out and make a hatch for the speed controller anyway have a great weekend
JAK
8x8 is a power hog I can try it on mine tomorrow and see. I would think u would be pulling 50 amps and 700 watts. I would watch out with that stock speed controller it comes with.
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Old Jan 25, 2013, 10:24 AM
chuck
santa barbara, CA
Joined May 2009
4,119 Posts
Quote:
Originally Posted by jstoll View Post
I put on an APC 8X8 and am running 4S 2200 45-90c nano techs. I really wanted to get out this weekend but its supposed to rain all weekend :-(
I cant find my inductive amp meter and need to buy a watt meter but was wondering if anyone knew what a stock motor pulls with an 8X8 on 4S?
I have much larger speed controllers with separate BECs if I need it....but I ended up gluing the wing on after the crash on the maiden so Ill have to cut out the old speed controller out and make a hatch for the speed controller anyway have a great weekend
JAK
enough to turn the motor into a nice heater, that is until it lets out the magic smoke!
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Old Jan 25, 2013, 11:46 PM
cant leave things stock
jstoll's Avatar
United States, KY, Lexington
Joined Feb 2007
1,457 Posts
I was hoping for some numbers :-)
Ive pushed many motors way way beyond their intended wattage the controller is more what I was worried about
thanks for your input though :-)
have a great weekend
JAK
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Old Jan 26, 2013, 08:18 AM
Flying is Freedom
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Annandale, VA
Joined Jul 2007
6,211 Posts
Quote:
Originally Posted by olllian View Post
Yes I recommend that lipo! And this is what I used. I added 3 to the back of the plane to make the cg perfect

http://www3.towerhobbies.com/cgi-bin...P?I=LXK204&P=8
I am guessing I would have to add less weight if I plan on using a 3s lipo. The largest I have is 2200mah.
Any suggestions on a 3s lipo setup?
I have some of those darn weights around here somewhere if I can find them
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Old Jan 26, 2013, 08:32 AM
Flying is Freedom
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Annandale, VA
Joined Jul 2007
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Quote:
Originally Posted by zooplane66 View Post
what camera did you use for this video?? Please send me a link my go pro doesn't seem to like flying much...
I don't want this statement taken personally nor do I mean to hurt anyone's feelings when I say this.
Zooplane66,
I'm glad that you have the ability to stand up and admit your purchase was not perfect for the activity you planned for it. I have made many mistakes in this hobby so I'm not pointing fingers either. I just find it funny that some of my flying buddies got the GoPro and found that it had that annoying bubble effect, not only annoying to themselves but also to those who watch the video, but they wouldn't admit they made a mistake in their purchase and will defend it even when they buy a cheaper camera that will do just as good if not better. I have one of those cheap keychain cameras and plan to buy another one because it does very good (not great) video and I'm happy with it.
I will add that the GoCamera is very good and has great clarity and high resolution and all that stuff. I just can't stand that bubble effect.

Boy, I can't wait to see what can of worms I opened with that statement
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Old Jan 26, 2013, 08:35 AM
Flying is Freedom
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Annandale, VA
Joined Jul 2007
6,211 Posts
[QUOTE=olllian;23880443]
Quote:
Originally Posted by mustflynow2 View Post

Thx and yes its 7x5
Almost sounds like an EDF I think it's cool when people add tape to the trailing edge of the prop and make it sound like a gas or nitro plane
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Old Jan 26, 2013, 10:54 AM
chuck
santa barbara, CA
Joined May 2009
4,119 Posts
Quote:
Originally Posted by jstoll View Post
I was hoping for some numbers :-)
Ive pushed many motors way way beyond their intended wattage the controller is more what I was worried about
thanks for your input though :-)
have a great weekend
JAK
well w/ electrics there are some general parameters that tell the tale. your combo of cell count, kv , motor weight and prop are way out of any workable area.

the 8x8 might work on 3 cells but your prop speed will be down. there is a reason the stock prop is what it is. if a 8x8x worked w/ a bigger esc , it would be that way from the factory. on 4's ,w/8x8 , the motor is grossly overproped and current will be very high and making heat will be what it does best.

chuck.
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Old Jan 26, 2013, 12:40 PM
cant leave things stock
jstoll's Avatar
United States, KY, Lexington
Joined Feb 2007
1,457 Posts
thanks for your opinion :-) did you run this motor and get this result? Im happy to post the data when I get it
I flew wings for many years and pushed motors really hard... this is a much slower turning motor though
I was the lead technician for Joby Motors and did large Brushless motor testing... Dynoed large brushlles motors on stands that I built.....I developed bond testing and assembly technique used to assemble these motors now in china...two JM1 motors I built got 80 hours of flight time with a human at the stick on a lazair ...maned flight with motors I built....
Ill let you know what I find :-)
JAK

edit... I also worked with the engineers at Zero Motorcycles and showed their powertrain engineer how to carbon wrap rotors....
I think the reason they dident put on an 8 inch prop and a bigger controller was because it will want to torque roll really bad on launch people allready struggle to launch them with a 7 inch prop and cost....but that is my opinion no data yet :-)
JAK
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Last edited by jstoll; Jan 26, 2013 at 01:04 PM.
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Old Jan 26, 2013, 04:13 PM
Flying is Freedom
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Annandale, VA
Joined Jul 2007
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Quote:
Originally Posted by Sky_Captain View Post
I am guessing I would have to add less weight if I plan on using a 3s lipo. The largest I have is 2200mah.
Any suggestions on a 3s lipo setup?
I have some of those darn weights around here somewhere if I can find them
I forgot to ask, How would the plane run on the stock prop with a 3s prop?
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Old Jan 26, 2013, 05:07 PM
chuck
santa barbara, CA
Joined May 2009
4,119 Posts
[QUOTE=jstoll;23937816]thanks for your opinion :-) did you run this motor and get this result? Im happy to post the data when I get it
I flew wings for many years and pushed motors really hard... this is a much slower turning motor though
I was the lead technician for Joby Motors and did large Brushless motor testing... Dynoed large brushlles motors on stands that I built.....I developed bond testing and assembly technique used to assemble these motors now in china...two JM1 motors I built got 80 hours of flight time with a human at the stick on a lazair ...maned flight with motors I built....
Ill let you know what I find :-)
JAK

edit... I also worked with the engineers at Zero Motorcycles and showed their powertrain engineer how to carbon wrap rotors....
I think the reason they dident put on an 8 inch prop and a bigger controller was because it will want to torque roll really bad on launch people allready struggle to launch them with a 7 inch prop and cost....but that is my opinion no data yet :-)
JAK[/QUOT

no , i would not ever go there, it's so far out of the efficiency curve there is no way i would do that to the motor. on the other hand i have done hundreds of static tests and mostly watts out with efficiency boils down to the mass of the motor being able to dissipate heat so the ir of the copper windings remains reasonable.

the 8x8 is a brute of a prop, i know i have 3 different planes w/ them on them. what u are asking is in the 800 to 1000 watt range and that takes a min 150 gram motor. this plane is designed for high pitch speed and u will not get that w/ 8" diam w/o a bunch of watts, been there done that.

chuck.
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Old Jan 26, 2013, 07:36 PM
cant leave things stock
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United States, KY, Lexington
Joined Feb 2007
1,457 Posts
I got 3 flights in today on the setup with the 8X8 and there were no fires or smoke but the batteries got pulled down fast ... I do think that a higher KV motor is a more efficient way to go faster then propping up the stock setup because as magnet speed increases so does efficiency to a degree... I had the controller set to high timing for when I was flying on 3S and should have kicked it back to medium or low for 4S as Im sure that made more heat ... so when my watt meter gets here Ill post some numbers ... the batteries came down mildly warm and it was kind of a long landing (cool down) but the controller did not seem hot on the ground.... I was doing half throttle up wind passes and wide open down wind and got 5 minutes max but I dident time them.... I did crash in the end as I was on low power (reduced power from low bat) and got down wind of myself coming in for a landing and stalled it up kinda high.... I can repair the fuse but will need another wing :-(
so thats the lame report on the 8X8
I dident get to do a back to back to see if it was much faster on the 8X8 over the 7X6 it probably was somewhat but the shortened flight times may not have been worth it
have a great evening everyone
JAK
edit I agree with chuck not a great prop for this plane
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Old Jan 26, 2013, 09:32 PM
cant leave things stock
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United States, KY, Lexington
Joined Feb 2007
1,457 Posts
I also wanted to say that with 1/2 oz of weight at the very tail corner of the plane that the 4S 2200 45-90C bats ballanced perfectly I was flying in 20MPH+ wind today and the down wind passes were spectacular :-) it does great in the wind if you arent trying to bring it in on reduced power :-)
JAK
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Old Jan 26, 2013, 10:32 PM
olllian
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United States, AZ, Chandler
Joined Nov 2011
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Nice
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Old Jan 27, 2013, 12:15 PM
cant leave things stock
jstoll's Avatar
United States, KY, Lexington
Joined Feb 2007
1,457 Posts
I was thinking of going with one of these http://www.hobbyking.com/hobbyking/s...arehouse_.html
on 4S running the 7X6 or 7X5 on 4S or a 2200KV ish motor with a 6X4 or 6X5.5 next
take care
JAK
PS Im bummed I wrecked the wing yesterday .... hit a small tree and crushed the wing pulling out of a stall yesterday.... the air seems still today but I do have my lil rare bear :-) on 4S and its a screamer too
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Old Jan 27, 2013, 02:54 PM
The Sequel
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Australia, VIC
Joined Sep 2011
1,262 Posts
Quote:
Originally Posted by jstoll View Post
I was thinking of going with one of these http://www.hobbyking.com/hobbyking/s...arehouse_.html
on 4S running the 7X6 or 7X5 on 4S or a 2200KV ish motor with a 6X4 or 6X5.5 next
take care
JAK
PS Im bummed I wrecked the wing yesterday .... hit a small tree and crushed the wing pulling out of a stall yesterday.... the air seems still today but I do have my lil rare bear :-) on 4S and its a screamer too
http://www.rcgroups.com/forums/showp...&postcount=292

It's a tight fit but can be done
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