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Old Sep 18, 2009, 01:39 PM
Registered User
Manchester, UK
Joined Feb 2009
283 Posts
Can I echo Ralf's suggestion regarding external whisker antenna location if you have a carbon boom - definitely a good idea to avoid 'reception brown out orientations' for 2.4GHz.

Also an extra vote for 'milled' contacts - we always used them in the lab in preference to cheaper items which often gave trouble after a few insertion cycles.

Enjoy flying

Skip
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Old Sep 24, 2009, 10:33 PM
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Rairwalk's Avatar
United States, FL, Lakeland
Joined Nov 2008
217 Posts
Hey branwell,
Maidened this big dude yet?

Rick
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Old Sep 24, 2009, 10:58 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Hi,

My ignorance made gathering all the right parts that would fit in the slender fuse a longer process then I would have liked.

The setup I ended up with is:

Hacker B40 FAI F5F motor.
AeroNaut 16-10 Prop
Vladmire 38mm spinner, 6mm offset.
Castle Phoenix 80 speed controller
Castle BEC ( acting as a voltage reg from the receivers pack )
A123 2300ma Motor pack.
2C 930ma Thunderpower pro lite receiver pack.
Spectrum AR9300 receiver with one remote.
Hiperion HP-DS090SCD servos in the spoilers.
Hiperion HP-DS095-FMD servos on the elevator and rudder.

The motor draws in the 90 amp and 850 plus watt range with the 4 cell A123 pack on the 16-10. Both the motor and the pack get warm pretty quick. The plane has more than 1 to 1 power to weight ratio at around 1/4 throttle.

On the 3 cell A123 pack, the numbers are in the 60 amp & 400 plus watt range. The plane reaches 1 to 1 power to weight ratio at a little over 1/2 throttle.

I dont know enough about electrics to know if the "getting warm" is happening too quickly with 4 cell A123 pack. Hacker say a 3C 3800ma lipo on a 16-10 / 17-10 should be about optimum. The A123 is a little higher voltage, so I am thinking on the 4 cell A123, the 16-10 might be okay.

That said, I should have a 17-10 in a few days and that might be a nice match to the 3 cell A123 pack.

Its supposed to rain Saturday, so I am hoping to fly it either tomorrow if I get the time or Sunday.
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Old Sep 24, 2009, 11:19 PM
Flyer
Rairwalk's Avatar
United States, FL, Lakeland
Joined Nov 2008
217 Posts
Have fun. Neat plane.

Rick
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Old Sep 25, 2009, 06:27 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
I run a 16x10-17x13 on my B40 FAI, on 2s, and get 100-110A. I have the 6.7:1 GB..
..a
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Old Sep 25, 2009, 07:58 AM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Andy,

If I might.

Which pack are you using?
What timing and switching rate are you using on the controller?

Thanks,

Branwell
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Old Sep 25, 2009, 09:35 AM
W0X0F
IBWALT's Avatar
United States, CA, Los Angeles
Joined Nov 2005
1,003 Posts
Quote:
Originally Posted by branwell
Hi,

Hacker B40 FAI F5F motor.
AeroNaut 16-10 Prop
Vladmire 38mm spinner, 6mm offset.
Castle Phoenix 80 speed controller

...

Castle BEC ( acting as a voltage reg from the receivers pack )
The motor draws in the 90 amp and 850 plus watt range with the 4 cell A123 pack on the 16-10. Both the motor and the pack get warm pretty quick. The plane has more than 1 to 1 power to weight ratio at around 1/4 throttle.

.
Nice setup but why skimp on the ESC? If your pulling 90 amps through a 80 amp ESC something is going to give. I guess it's a good thing that you have the CC BEC so you will still have power to the rx when the ESC burns up. Also the B40 LMR has a 60 amp max draw. This can be exceeded for short motor runs but you want to make sure you have adquate cooling and allow adquate time for cooling between motor runs.

IMHO I would get a ESC that can handle more amps also go out and get an Eagle Tree Logger so you will know what's going on when you turn the juice on. It will help you tune your setup and achieve max performance without burning something up.

Walt

PS: Here is a link to my AVA-e setup that has the Eagle Tree graph attached.
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Last edited by IBWALT; Sep 25, 2009 at 10:07 AM.
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Old Sep 25, 2009, 11:50 AM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Hi Walt,

I have a 110 amp hacker speed controler, only I can't figure out how to get it in the fuse along with all the other stuff. The fuse size is one of the main reason for the a123 batteries. A long thin tube fits better than the more square shape of the lipo.

The 80 amp Phoenix is rated at 80 continuous and 120 burst. Given the motor run time is unlikely to be more than 15 seconds, i am hoping it will hold together.

Branwell
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Old Sep 25, 2009, 02:09 PM
W0X0F
IBWALT's Avatar
United States, CA, Los Angeles
Joined Nov 2005
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Yes, once you get past the PHX 80 the speed controllers get pretty large and are hard to place in the fuse. But I don't know if burst lasts as long as 15 seconds. I thought that burst was more like momentary (one or two sec.). Let us know how it works out. I considered a larger ESC myself but could not figure a way to use one without a rather long wire run from the ESC to the motor. Another thing that I was disappointed about was the amount of lead that I had to stick up under the motor to get the c/g right (95mm). With a 2s lipo I had to stick about an ounce of lead under the motor to get it to balance. That sort of took away any advantage of having a CF motor can.

Walt
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Old Sep 25, 2009, 04:23 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Hi,

I got the AVA in the air today with the 3 cell A123 pack and 16-10 prop.

Went great. No problems.

The A123 will go about 5 full power climbs.

Ended up adding a little lead under the canopy to balance the plane further forward. It balances fine with the 4 cell pack, but at the moment, I would rather have a little lead and not worry about anything burning out until I learn more about the plane.

Speaking of learning more.

The split spoilers don't need much compensation. I have about 14% up elevator mixed in.
They do work well to slow the plane on approach and don't drop it like a stone.

Branwell
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Old Sep 25, 2009, 06:49 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Weighed it with the 3 cell A123 pack. 64.8oz
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Old Sep 25, 2009, 07:22 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Receiver install.

The reciever is "stuffed" into the fuse and sits just about under the center of the pod.

The two antennas from the receiver run forward into the kevlar section and are taped to the fuse walls, one horizontally, one vertically.

The antenna from the remote comes out of the top of the pod and rests in between the two center ribs of the wing.

Range check was solid with no major loss of frames and no issues at any angle in the air.
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Old Sep 25, 2009, 07:48 PM
Registered User
Terre Haute, Indiana, USA
Joined Aug 2004
959 Posts
Quote:
Originally Posted by branwell
Weighed it with the 3 cell A123 pack. 64.8oz
That is a very nice AUW for a 4 m e-sailplane, and even with that fairly heavy A123 pack. Seems like you could get the AUW under 60 oz with a suitable lipo pack. Any problems with getting the right CG? Any room for ballast if needed?

FF
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Old Sep 25, 2009, 09:28 PM
The Lone Blue Plaid Flyer
Bob Cook's Avatar
Seattle
Joined Jan 2003
7,586 Posts
Hi Branwell,

PLEASE post some flying photos of the plane if possible. OR some ground shots, something, anything. Just some photos of it in the air would be nice.

Bob in Seattle
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Old Sep 25, 2009, 10:26 PM
W0X0F
IBWALT's Avatar
United States, CA, Los Angeles
Joined Nov 2005
1,003 Posts
Congrats on a successful first flight. I'm sure you will have many more memorable flights with your AVA. I would still suggest the Eagle Tree logger. It does not take up much room and it will give your the ability to fine tune your power system.

Walt
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