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Old Apr 09, 2010, 10:13 PM
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Super AVA-E Pro Motor and Servo Questions

Hello All,

I have a shiny new Super AVA-E sitting in the box and I am starting to amass the parts required for the build. My Frankenglider project has gotten me more accustomed to flying a large glider, so I want to get the AVA together and flying. Realistically this will take until mid May as I have quite a few commitments between now and then. I do want to order everything I'll need so I can get to it when my schedule opens.

My criteria for outfitting the AVA is simple, I have the dueling priorities of light weight, affordability and durability. The Frankenglider pushes the envelope on affordable 12' WS gliders at $280 total. That is obviously not the benchmark. From reading the AVA-E and Longhorn-E threads I've gotten lots of ideas, but need some concrete input applicable to my specific project. One of the issues I want to consider is weight and balance, I don't want to have to add ballast except as a last resort.

For motors I've looked at a lot of options and read a good bit I don't need competition grade power. A solid 45 degree climbout would be great. First I have these three in my toolbox:
Hacker B50 10L 5.2:1 (322g)- Heavy
Himax 3618/4522 XX:1 (228g)
AXI 2826/8 w/4:1 (262g)

If I were to purchase a new motor, these are the ones that fit the budget/criteria:
MVVS 5.6/690 (268g, $146)
Mega 22/30/4 (220g, $135)
Mega 16/25/3 4.4:1 (168g, $165)

I've looked at the Hyperion glider outrunners, but at 37.8mm I don't think they'll fit.

For controllers I have a Castle 80 sitting in the toolbox as well.

Now onto servos, I used the servo torque calculator to figure that a MG 9 gram servo should do thew trick in the tail. I have DS 09D's, will they fit and have sufficient torque?

I would like feedback on the above, as well as help determining what the best combination will be to get the plane to balance ballast free at the lightest possible weight. Some many of you have so much experience in these things that I know I can avoid a lot of mistakes and heartache by soliciting input early on.

Thanks,
Wardo
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Old Apr 11, 2010, 04:30 AM
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Manchester, UK
Joined Feb 2009
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Wardo

I can only comment about one motor in particular as I haven't used the others side-by-side for comparison. The MVVS 5.6 690kv Glider motor is a great unit, beautifully smooth and balanced and powers my standard 3.2m AVA to perfection in our UK height-limited comps when set for 200m climb in less than 20s. A number of others also use it in similar applications. A 3S lipo in the range 2600 - 3700mAh can normally be shifted around to balance the rig with no added lead.

A bunch of us have started using the Hyperion Atlas digital servos (DS9AMD, DS95TMD and DS13TMB) and have found them to be excellent all-round units. So yes, DS9AMDs are great in the Ava tail.

Hope that helps.

Skip
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Old Apr 11, 2010, 08:24 AM
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USA, VT, Putney
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Quote:
Originally Posted by SkipT35 View Post
Wardo

I can only comment about one motor in particular as I haven't used the others side-by-side for comparison. The MVVS 5.6 690kv Glider motor is a great unit, beautifully smooth and balanced and powers my standard 3.2m AVA to perfection in our UK height-limited comps when set for 200m climb in less than 20s. A number of others also use it in similar applications. A 3S lipo in the range 2600 - 3700mAh can normally be shifted around to balance the rig with no added lead.

A bunch of us have started using the Hyperion Atlas digital servos (DS9AMD, DS95TMD and DS13TMB) and have found them to be excellent all-round units. So yes, DS9AMDs are great in the Ava tail.

Hope that helps.

Skip

Thanks Skip,

I've only heard good things about MVVS motors. It is on the heavier side of what I am considering but I am sure the quality is there. it looks like Puffin Model is my likely source. I looked at their website and they don't list an e-mail address. It is a bit of inconvenience to call from the States, I wonder if there is an address out there?

Regards,
Wardo
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Old Apr 11, 2010, 08:54 PM
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Canada, ON, Burlington
Joined Sep 2004
703 Posts
I have ordered quite a few things from Puffin, and they have all arrived within a week. Great service, and very helpful. They usually charge you the VAT (value added tax) even though you are out of the UK, and use that to pay for the shipping. For an email try;

sales@puffinmodels.co.uk

I have an MVVS motor for my Pulsar 3200, and it's a great motor and loads of power, great value IMHO.
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Old Apr 12, 2010, 08:04 AM
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Thanks Flyboy,
I appreciate the input on MVVS. I am still trying to figure out how light I can go in the motor department. My general experience with e-sailplanes so far is that the crux of a light build is keeping the tail as light as possible. I read in the Longhorn thread that the OP had a 141g motor but needed an ounce of lead (I may misremember this). That indicated to me that I could theoretically get away with a motor as light as 170g. Of course there are tons of variables, but I have to start somewhere....

Regards,
Wardo
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Old Apr 12, 2010, 09:19 AM
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Andy W's Avatar
Marietta, GA
Joined Jun 1999
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FWIW, I am running a B40 in my (regular) AVA on a 2s 5000mAh pack, and it produces "just enough" power to be competitive in LMR events, around 3500fpm climb rate.
I come in just over 3lbs..
..a
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Old Apr 12, 2010, 10:55 AM
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Graham 65's Avatar
Chipping Norton, UK
Joined Jul 2006
393 Posts
Hi Wardo,

How much room do you have, could you use a 35 mm outrunner?
Maybe an AXI 2826 12?

Interested to see what weight you end up at.

Graham
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Old Apr 12, 2010, 01:16 PM
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The Pro fuse is limited by the access hatch opening. You can squeeze a 36mm motor through there. All bets are off larger than that. I have a Hyperion on the way for the Frankenglider, I'll try fitting it on the AVA Pro, but I don't hold out much hope as the wires will be in the way. The AXI might work. I haven't dug mine out yet. It is is a box at the bottom of my "kits to be built" pile. Andy, a B40 or smaller Neu is what I wish I already owned, but I'd rather not have to buy one. At 48 ounces, you are right at my dream weight. I am intrigued by the direct drive motors, I have had surprisingly good luck with my Turnigy 540/810kv in the Frankenglider. I did torch it, but that was totally my fault, I over propped it because that's all I had around. It actually held up surprisingly well. I don't want to use that motor on the AVA, but at 180g and 500w it is actually a good data point. I am going to contact Etienne at Icare and see what he says about the smaller Mega with a gearbox.

Regards,
Wardo
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Old Apr 13, 2010, 12:16 PM
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United States, IN
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Wardo,
I have a B50 in my longhorn and I still needed 3/4 oz. of lead to balance. I used Hitec 125 thin wing servo's in the tail and I don't know how they compare weight wise to your servo's. I have a Hyperion 3300 3 cell and I don't think anything bigger would fit. Fly's great at 66 oz.

Marc 540
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Old Apr 13, 2010, 02:12 PM
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Ralph Weaver's Avatar
Indianapolis, IN USA
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I love my Hyperion in my Topaz. The new Hyperion glider versions can be mounted with the wires out the back.
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Old Apr 13, 2010, 06:48 PM
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Quote:
Originally Posted by marc 540 View Post
Wardo,
I have a B50 in my longhorn and I still needed 3/4 oz. of lead to balance. I used Hitec 125 thin wing servo's in the tail and I don't know how they compare weight wise to your servo's. I have a Hyperion 3300 3 cell and I don't think anything bigger would fit. Fly's great at 66 oz.

Marc 540
Marc,

That is helpful, you've offered an excellent concrete data point.The 125's are advertised as 24g's, the Hyperions are 9g with some relative loss of published torque. I don't know the exact ratio to balance additional tail weight on the Super AVA, but a quick glance at the picture tells me it is roughly 3:1. Of course I could be totally off.... All things being equal, that might indicate that the 30g difference in tail weight is worth 90g at the nose. If so I am wasting my time trying to get below about 245g on the motor. Part of my assumptions were based on Branwell's Longhorn thread. He found a good balance using 19g servos in the tail with a 142g motor, 21g of lead and a123 pacs varying between 280g to 364g. Having said that, we are comparing a Longhorn to a Super. I probably should post over there and confirm all my info.

My rough calculations indicate that I should be able to build the Super AVA-E right around 60 ounces with a 220g motor and corresponding components. Having said that, my Frankenglider flies incredibly well at 75 ounces, and is not even remotely aerodynamically clean. I am not really obsessed by the weight, I am just figuring if I am going to buy something I might as well try to do a light build. I just like a goal to shoot for. No matter what, I am sure that it is going to fly far better than anything I've owned or flown.

Ralph, thanks for the input. I've only heard good things.

Regards,
Wardo
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Last edited by wardo78; Apr 13, 2010 at 09:24 PM. Reason: Bad math!
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Old Apr 14, 2010, 05:39 AM
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Wardo,
I have had two Hyperion DS09AMD servos in my standard Ava tail for almost two years.They have had plenty of the sort of abuse that normally strips gears(banging into the garage door etc.)and are still fine.They centre very well and despite heavy use have developed no slop.
They replaced HS 125 servos in the same model and saved about 80gms, or so, in the nose.
I think they would be suitable for your model.
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Old Apr 14, 2010, 07:12 AM
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Thanks Painter. I will definitely use the Hyperions. I've also had good luck with the MKS 450DS. They have approximately the same torque and excellent centering.

On the motor front I've heard back from a few sellers. For a lighter MVVS motor, Puffin Models recommended the 4,6/840 which weighs 206g. The power rating is a little hard to find, but it looks to pull a 14x10 prop on 3s. Esprit recommended a NEU 1110/1Y, again pulling a 14x10 on 3s. This motor weighs 196g with gearbox and is rated at 400w continuous, 1000w surge. I am not sure how many watts I should be targeting, but the Frankenglider climbs at close to 45 degrees with a Turnigy 540/810, 14x10 and 3s. I measured this system at 405w max. The FG-E weighs 16 ounces more than the likely AUW of the Super AVA-E Pro, so I think I've answered my own question.... Of course any additional input is appreciated.

Regards,
Wardo
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Old Apr 14, 2010, 04:30 PM
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United Kingdom, England, Stratford-upon-Avon
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Wardo, I suggest you tape the plane together and tape the actual (or equivalent weight) components in place and see what minimum motor weight you will need to balance it. Don't forget the rear extension leads which could weigh as much as the servos.

When I was estimating this with some early production parts that we received I estimated that the prop/gearbox/motor/ESC combination would have to weigh around 320g. I think I was assuming that a 200g battery would be used.

See http://www.hyperflight.co.uk/product...UPER-AVA-PRO-E

Regards,

Neil.
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Old Apr 14, 2010, 05:41 PM
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Thanks Neil,

I've used that technique before and it seems applicable here. It would be nice to get it right and have it balance without any ballast, and this seems like the most sure fire way to get there. I have used your website before, I appreciate the details you provide. I used the Pulsar 3.6 review for motor ideas. At this point I am pretty settled on a Neu, I just need to figure out which model.

Regards,
Wardo
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