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Oct 24, 2003, 08:08 AM
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asw-28 3m electrify or not?


I bought my hf asw with the intention of electrifying it with a hacker b-50 on 16 x 1700 cp.With an auw of 9 to 10 lbs I wanted to know if she would thermal well or just become a lead slead?With out the electric motor she weighs about 61/2 pounds with radio and about 19 onces wing loading.I assume with the added weight it should increse the wing load to aprox 23 onces.
My experience with scale gliders is limited at best so before I go and spend 500 on electrics I would appriciate your opinions.

DANIEL
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Oct 24, 2003, 10:56 AM
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96S14's Avatar
I think a 3m plane at that weight would become a lead sled. At best, I would try a high power, lower cell count, high current drive system to get shorter, powerful runs, at a huge weight savings. Why not go 10 FAUP's or CP1700's and a hotter wind B50? You shouldn't need 16 cells to get that plane in the air.

I am in the process of planning a NYX electric conversion, and the drive that I've heard works well is the B50-9S on 10 RC2400's or 12 1950 FAUP's. Something along those lines would be better I think, though I would stay away from the 2400's to save weight.

Personally, I would keep that plane for the slope, winch, or aerotow.

Hope that helps a bit.

Ryan
Oct 24, 2003, 01:52 PM
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Thread OP
My exact power plant will be a hacker b-50 13s on 16 cp 1700 runing a 18-10 prop.This combination should pull about 56 amps and produce about 700 watts of power.(figures based on motocalc)As for the slope we don't have any close ones to use and yesterday was actually the first time I went to a sight which was amazing.The only problem is it is 2 hours away and the wind has to be nw.Which to say is not often.So from what i gather you would rather electrify something which it is designed for rather then a conversion?

In general are scale planes hard to thermal?
Oct 24, 2003, 02:22 PM
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96S14's Avatar
No slopes? Where in Beautiful Canada are you? Saskatchewan? Here in Calgary we have slopes virtually everywhere.

I would take your drive system and put it in a 3 meter thermal ship. It would perform great there. Also, don't trust motocalc with these drive systems...for me it overestimated current by 25% and has been so unbelievably wrong on some simple "changes" to a setup. I think what you have will easily pull the scale plane up, it's just that I think the plane won't fly too nicely anymore.

There's a guy in our club running the B50 13S and an 18 x 12.5 prop on 12 cells in a Stork and though it does not climb like a rocket, it gets to winch height pretty quickly. That plane also glides quite nicely. I would buy a lighter airframe, but the drive is pretty good. I would also get a slightly bigger prop and pull more current (probably a 20" prop of some sort)

As for thermal abilities of scale planes, it all depends. I have a (very light) Gerasis 3.2m DG-600 and it flies OK. I have thermaled it and it's not too bad. Your plane would probably perform a little better as compared to the DG, just because it probably has a better airfoil on it (even though it weighs more).

I also have a 4.2m Rodel ASK-21 and that plane will out thermal any 3m molded competition TD plane. It's simply incredible. So to answer your question, yes scale planes can thermal, and they tend to do it far better as they get bigger.

Hope that helps,

Ryan
Oct 24, 2003, 02:59 PM
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RYAN,

thanks for the info,I am located in la belle province(montreal).By the way you mentioned winching it,have you had any success in this type of launch.I will assume you are using a rog technique with a bridal hook set up.How much height can you get?
Oct 24, 2003, 03:08 PM
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The few times I have winched, I did not ROG but rather had a launcher throw the plane when there was plenty of tension on the line. Our field has pretty deep grass, so ROG can be risky from a ground loop perpsective. I think it's probably still the safest way to go though (rather than throwing the plane).

You need to absolutely use a bridle to launch (don't ask me how I know!!!). If you use a bridle, launch is a non-issue.

As for altitude, it depends on the position of the tow hooks and the length of the winch line. Our field is short, but we use very powerful winches. I could easily get up a few hundred feet...which is enough to find lift.

I'd sya try winching first, since it'll only cost you two tow hooks and maybe an ounce to the plane. If you're still not happy, them look at electric.

Hope that helps a bit. Let me know if you have any other questions,

Ryan
Oct 24, 2003, 03:33 PM
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Thread OP
Once again, thanks for the info.

RYAN when you have a chance could you take look at the discuss 2b fully molded on the icare-rc web site.I would like to know if you think this would make a better conversion if I go with lighter equipment?By the way I will build a winch since I have acsess to a full machine shop andd sheet metal shop.I will use the basic long shaft 12 volt starter but incorporate bearings and aluminum end caps with extra vents for better cooling.I was even thinking of machining a complete knew case out of aluminum.As for the above question I do realize it is kind of rhetorical(I hoped I spelt it right)but I love the scale look and at the same time try to convert a few "glow" guys to silent flight?

THANKS

DANIEL
Oct 24, 2003, 09:26 PM
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wakumann's Avatar
Ryan,
the ASW 28 with the B50 and 16 cells is overpowered and a waist of energy and money.
You will get good performance with 10 or even 8 cells.
I fly electric gliders since the last 15 years in all sizes and shapes, (but only if the next slope is to far, or for lack of wind)
Attached picture of Esprit 3.3m with just 10 cells and the 4,2 m LS 6 flys with 14 cells.( before Brushless motors were available)
Cheers
Thomas
Oct 24, 2003, 09:31 PM
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wakumann's Avatar
OK, here's the Mueller Esprit with an geared 600 sized brushed Motor which runs 3:30 min on 10 cells with an RF 17 x 10 prop.
I have also the 2.5m Discus from Icare it's really an nice Model but never used it on a winch.
It belongs on a slope and for electric retract it,s to small to perform well.
(my opinion)

Cheers
Thomas
Oct 25, 2003, 12:31 AM
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96S14's Avatar
Quote:
Originally posted by wakumann
Ryan,
the ASW 28 with the B50 and 16 cells is overpowered and a waist of energy and money.
You will get good performance with 10 or even 8 cells.
Thomas,

Is that not exactly what I said??? Take a look from my first post:

Quote:
I think a 3m plane at that weight would become a lead sled. At best, I would try a high power, lower cell count, high current drive system to get shorter, powerful runs, at a huge weight savings. Why not go 10 FAUP's or CP1700's and a hotter wind B50? You shouldn't need 16 cells to get that plane in the air.
Oct 25, 2003, 12:40 AM
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96S14's Avatar
Quote:
Originally posted by GHOST RIDER


RYAN when you have a chance could you take look at the discuss 2b fully molded on the icare-rc web site.I would like to know if you think this would make a better conversion if I go with lighter equipment?
I would go bigger, or not at all with a scale electric glider. There's a thread on the Electric sailplanes forum that is about a Rodel Ventus (the thread starter was Warren Kriesel) with a Plettenberg motor. That plane would soar very well, but you're looking at big bucks (and an overall big plane). If you want to stay small, I would say you're better off giving up appearance for far improved performance and buying a purpose designed ship. Then get a bigger scale glider and either convert it to electric or fly it on the slope/aerotow/winch.

Personally, I love the looks of the scale planes as well, and I must say that all my scale planes that are less than 3.5m are used strictly on the slope...they just don't perform that well in any other setting (or at least, I have other planes in my fleet that fly far better for those other conditions, so the scale planes stay home in those cases)

As for building your own winch, that's the way to go, and you should be able to make a nice one for not too much money if you have access to a shop. Good luck.

I hope I've answered your questions adequately. Let me know if you have any lingering thoughts. I'm not trying to sway you away from doing what you really want, but I'm just trying to be realistic about the outcome that you're likely to see.

Ryan.
Oct 25, 2003, 08:43 AM
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Thread OP
RYAN,

Your advice has been appreciated as well as your patience for answering my some what newbe questions.I am definatly going to think it over.Like you said better to have a purpose built glider then a conversion.Just the electronics with esc and battery was about 700 cdn.Thats more then what I paid for the plane.And if it didn't fly well I would really be disappointed.

THANKS

DANIEL
Oct 25, 2003, 10:18 AM
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96S14's Avatar
Daniel,

No problem on the help. It's nice to talk on these forums when you know someone is listening and actually contemplating your advice, as opposed to just taking it and following it word for word. That's where this hobby is the most rewarding...when you take some knowledge, and try to put your own thing together and see how well it works.

Anyways, I know it's a lot of dough, but you're still best off either keeping the setup you have and spending another pile of dough to get a porpose built, reasonably large airframe (like an F5J type airframe), or trying to trade/sell the setup and then buying a smaller plane along with a smaller/lighter setup. If you can handle the looks, the Moebius from Icare flies quite nicely, and it comes with both an electric and glider nose, so you'd have a pretty good airplane for two purposes. It would work well on the winch, and is strong enough for all but the most heavy of launches (pedal to the metal with a stiff headwind), while being perfect for the drive system you have. It's expensive, but not as fully molded planes go, and I have seen it fly and it really is a nice plane (again, if you can handle the looks of the silly wingtips)

Also, if you are in Montreal, why not ask Etienne if he will trade the motor for another wind (assuming you have not used it)? He may be good about it. I would go with a B50-9S on 10 cells and an 18 x 10 or 18 x 12.5 prop. It would be a powerful setup, without being a really ridiculous 100+A system.

Check out the Moebius at: http://www.icare-rc.com/moebius.htm
Etienne's price is very fair for Canadians (though the strength of the dollar is starting to change that).

Ryan.
Oct 25, 2003, 12:35 PM
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Thread OP
RYAN,

Funny you mention that plane,I was just looking at it this morning
I think this plane is a love it or hate.I like it.Actualy it was with etienne on thursday that i experience my first "real" sloping time.
Those glow guys do not know how lucky they have with thier cheap arf prices.You are right 700usd is a lot but I am sure I would have more sucsess and in turn have more fun.I will give you an up date in the future.By the way is the guy who has it ,is he really happy with it?

THANKS

DANIEL
Oct 25, 2003, 02:24 PM
somewhere in South America
ShredAir's Avatar
For this 3-m ASW, I'd consider a LMT1525/8D with 8:1 gearbox on eight 2600-3300 NiMH cells. This would swing 17x13 to 20x13 props, give you brisk performance, yet keep the weight down.

Dieter Mahlein
http://shredair.com


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