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Old Sep 25, 2009, 10:18 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Hi FF,

The fuse is really tight. To an old glider hack, it might seem a cave, but to me......

The three cell A123 2300ma pack weighs 9.75oz with wires.

There are 2 cell Lipos that would likely work well and be a little lighter. That said, I think you would end up needing to add nose weight to compensate. I already have .75oz at the forward part of the hatch.

A 3 cell Lipo would be good, but would require that you mount the speed controller behind it. Would make for a trickier install, but you could get more power and capacity then the A123's.

As to ballast, yes you could add ballast, but you would need to be a master installer to get it in there. The main problem is the hatch is so small. It makes working and securing things in the fuse really hard going.

A question might be whether you would want ballast. I hear a lot of people ballasting the pure glider AVAs, but the "E" is already 20 plus oz heaver ( very similar to the amount of ballast added to the pure glider version )

Best,

Branwell
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Last edited by branwell; Sep 26, 2009 at 11:25 AM.
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Old Sep 25, 2009, 10:28 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
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Bob, I'll get some pics of it with a Supra on Sunday if the weather cooperates.

Walt, thanks for the suggestion. I have a lot to learn about sailplanes and electrics, and what you suggest is definitely getting added to my list of things to get.

Branwell
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Old Sep 26, 2009, 05:50 AM
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Terre Haute, Indiana, USA
Joined Aug 2004
959 Posts
Quote:
Originally Posted by branwell
....A question might be whether you would want ballast. I hear a lot of people ballasting the pure glider AVAs, but the "E" is already 20 plus oz heaver ( very similar to the amount of ballast added to the pure glider version )....
Yup, the extra weight might well be enough ballast for most flying conditions, especially if you avoid the windier days. Just seems to me that your AUW is pretty low for a 4 M sailplane. But then again, I have never flown an AVA of any kind. I'm sure that some AVA devotees out there can shed some light on this matter.

FF
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Old Sep 26, 2009, 11:12 AM
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Northern VA
Joined Apr 2006
90 Posts
Hi Bob,

Here are some not so good pics from today. The weather is very flat, gray.

That said, there is enough lift that the AVA will stay up where the Radian wont.

Branwell
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Old Sep 26, 2009, 11:39 AM
The Lone Blue Plaid Flyer
Bob Cook's Avatar
Seattle
Joined Jan 2003
7,586 Posts
VERY VERY nice plane and great shots too. Thanks for posting them. I have a Mini AVA and really enjoy it a lot. I don't have room to fly a plane this big around here. I'm glad you do.

Bob in Seattle
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Old Sep 26, 2009, 11:51 AM
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branwell's Avatar
Northern VA
Joined Apr 2006
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Some flight notes:

So far I have only flown the AVA in very light lift conditions in virtually no wind. So these notes apply to those conditions.

The plane can be flown at a crawl just above stall to work really really light lift. The rudder and elevator are very effective making control easy, however, it does have a sharp stall. That said, it does broadcast the impending stall so if one is paying attention.......

Given the light lift with which it can maintain altitude, I imagine on normal days with normal lift, keeping it down might become a large part of the flight regime.

Branwell
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Old Sep 27, 2009, 07:13 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
Quote:
Originally Posted by branwell
Which pack are you using?
What timing and switching rate are you using on the controller?
I started out with 7-cell GP2200 NiMH, and the 17x13 was too much for this pack. Switched to 2s5000mAh Neu LiPo, and it had a good jump in power. Tried the 17x13 again and it had a much better climb rate. Perfect combination!

The controller has no programming that I am aware of, other than brake/no brake - it is an early Hacker 105A, not even "lipo friendly" which makes no difference, as I only use a fraction of the pack capacity.

The pack is larger than it needs to be as far as capacity goes, but at the time, was the smallest that could handle the 100A current draw. Of course, there are many lighter packs able to handle that now, but I would never get the model to balance with a smaller pack..
..a
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Old Sep 27, 2009, 08:19 PM
I do this for fun!
Sunshine Coast, Australia
Joined Sep 2004
1,197 Posts
Hi branwell,

lots of guys use your motor in our Aussie LMR glider comps. They can be pushed to 150A on 3S so long as you keep the runs to 5-6 secs max. You won't need more than that!

The PHX80 is a popular controller too. They handle the 150A for short runs no problem.

Hacker always under-rate their motors to an incredible degree, and Castle have an excellent reputation of standing behind the PHX-80 and above ESCs, even when they are used well beyond their rating.

Short runs are the key to reliability because there is very little heat buildup, if any.

Enjoy your plane, it looks fantastic!

Ken.
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Old Oct 01, 2009, 10:16 PM
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Northern VA
Joined Apr 2006
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Went over to a friends place and got a great day soaring with the AVA.

Came to a good compromise on the CG.
Got the flight modes set, Thermal, Cruse, Speed.
Played with the 3 and 4 cell A123 packs with an RF 17-10 prop.

The plane has a long enough boom that it can be flown really tail heavy without getting overly pitch sensitive. That said, if you put it in a 45 degree dive, it accelerates and starts to tuck just getting faster. Can be a spooky feeling.

I set the CG so it will pull back to level from a dive in the Thermal flight mode and run fast in Speed.
Plenty sensitive to find thermals and easy to core them tightly.

The 4 cell A123 on the 17-10 ran the Watts Up off the Amp meter. I don't know how many amps it draws but its over a 100.
The vertical was really really strong needing little more than 10 seconds to get some good altitude, but the extra weight over the 3 cell pack was very noticeable and not worth the extra vertical.
If I can find a good 3C lipo that weights similar to the 3C A123, can push 100+ amps, and fit, I'll get it, otherwise I plan to stick with the 3C A123.

I am loving this glider.
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Last edited by branwell; Oct 01, 2009 at 10:56 PM.
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Old Oct 01, 2009, 10:24 PM
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branwell's Avatar
Northern VA
Joined Apr 2006
90 Posts
Hi Ken,

Thanks for the info.

My problem getting to 150 amps is trying to fit the battery in the plane. The fuse is very tight on this version.

Branwell
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Old Oct 01, 2009, 11:04 PM
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Rairwalk's Avatar
United States, FL, Lakeland
Joined Nov 2008
204 Posts
flight modes

branwell,
May I ask what you are doing with the programming for this RES bird to set up thermal, cruise, & speed modes? Just curious. I understand with the flapped AVA-E. I programmed 1mm down flap for thermal and 1mm up for speed.

Rick
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Old Oct 01, 2009, 11:22 PM
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Northern VA
Joined Apr 2006
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Hi Rick,

I'm using flight modes to alter trim and expo.

There is also some mixing ( not mode related ).
Spoiler / Elevator mix for a flat decent.
Throttle / Elevator mix for hands off assent.

Branwell
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Old Oct 01, 2009, 11:24 PM
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United States, FL, Lakeland
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Thanks. Nice bird.

Rick
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Old Oct 02, 2009, 05:44 AM
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Terre Haute, Indiana, USA
Joined Aug 2004
959 Posts
Sounds like a nice-flying e-sailplane! Have you put it up on a windy day? I was wondering how well it deals with wind.

Sounds like the A123 packs are working well for you. But as for a lipo pack, your best bet may be a 3S2P 2200 or 2600 (35C) pack. Such a pack should be comparable in size and weight to your A123 packs, and ought to be able to handle 100 amps. The higher capacity 3S1P packs may be too awkwardly shaped for your fuse.

However, if you are planning to fly through the upcoming colder months (if you live in a cold area), then the A123 packs are probably the best choice until spring.

FF
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Old Oct 02, 2009, 08:02 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
No reason to think it would be much different from a regular AVA in wind. They can handle more wind than I am happy flying in!
..a
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