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Old Jun 07, 2013, 02:42 PM
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good thermal ship AND acrobatic

In an electric sailplane are the two mutually exclusive? I like to do some acrobatic flying while gliding, but I also like to be able to stay up with out motor assist.

Any reasonably priced, around $200-300 ships that do both. I've looked at the 2.5 M Swift http://www.hobby88.com/shop/product_...d906ce7ff1cc68 and the 3M Fox http://www.hobby88.com/shop/product_...d906ce7ff1cc68

I'm just doubting their thermal abilities.

And I really like scale sailplanes rather than contest types that I can't afford anyway
Thanks

Randy
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Old Jun 07, 2013, 03:09 PM
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Swifts and Foxes and their ilk have high wing loadings, they are never going to be good thermallers. Gliders of a more conventional design can, however, also do pretty well at aerobatics.. Do you want to stick with scale, or can a sport model do?

Chris
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Old Jun 07, 2013, 03:32 PM
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Hi, Randy.

From what I have read the scale aerobatic gliders like the Swift and Fox sacrifice quite a bit of thermal soaring performance for not a great deal more aerobatic performance. I have a 2 meter foam ST ASW 28 that soars very well and is quite aerobatic now that I have replaced the stock ailerons and dysfunctional internal linkages. Loops, rolls, spins, hammer heads, tail slides, and inverted flight are quite decent. When I want to soar I use my lightest battery and when I want energy retention I use the heavier ones but it will still soar in strong lift at a higher weight.

I'm almost certain that my next glider will be the Fly Fly DG 1000. It sounds like it's probably the best thermal machine in the Fly Fly 2.5 meter line. Will it soar as well as a lighter foamy? Probably not but I'm hopeful that it will soar if there's any lift at all and should be a little better aerobatic performer than a foamy due to a stiffer airframe. Plus, it's bigger and it's not foam.

I'm also considering getting an extra wing kit that I would add flaps to for camber control while soaring and then I would reinforce the other wing for aerobatics. I'm using my ASW 28 as a test mule to see if I think I can get by using just the ailerons for camber. It sounds like it can increase the natural propensity of a scale glider to drop a wing in a stall and that might get hairy. We have a big flying day scheduled for tomorrow and I'll let you know how it works.

There are also a few "warmliners" available that won't break the bank. Esprit Models has several with moderate wing loadings for example. I realize that they aren't scale but would probably perform a little better over all. They just wouldn't look quite as cool whistling across the field at ten feet!

Cheers!
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Old Jun 07, 2013, 03:36 PM
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BTW. My Specter 1800 is a very good general purpose sailplane and also fully aerobatic (except that I still haven't figured out how to get decent spins with a V-tail) at a very good price. The genuine Passer-X sounds like it's a bit lighter and better overall quality.
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Old Jun 07, 2013, 05:05 PM
flying at SCMAC
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i my self have just been through this decision my self, i ended up going with the asw 28 2.5m, not exactly a thermal ship but i do like the scale and i will be doing some slope as well, the condor evo 3m i think would be a good all rounder in this category, the pic shows the 2 side by side
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Old Jun 07, 2013, 08:06 PM
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Originally Posted by Woodstock 1 View Post
Swifts and Foxes and their ilk have high wing loadings, they are never going to be good thermallers. Gliders of a more conventional design can, however, also do pretty well at aerobatics.. Do you want to stick with scale, or can a sport model do?

Chris
Hi Chris:

Sport would be fine, IF the payoff is there. IE, it does what a scale ship won't. Do you have one in mind? Please share. Otherwise, I'd prefer scale. I've been looking at the airfoil shape of all of the FlyFly sailplanes offered by Hobby88. I'm assuming, I know can be dangerous!, that a more symmetrical airfoil is what I'd be most happy with. OR does that tend to kill it's thermal ability?

Which begs a question. What can be read into a planes flying qualities based on wing airfoil?
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Old Jun 07, 2013, 08:07 PM
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Originally Posted by peterlngh View Post
BTW. My Specter 1800 is a very good general purpose sailplane and also fully aerobatic (except that I still haven't figured out how to get decent spins with a V-tail) at a very good price. The genuine Passer-X sounds like it's a bit lighter and better overall quality.
I have a problem with V tails. Half the time I can't tell if they are coming or going. Old eyes I guess.
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Old Jun 07, 2013, 08:12 PM
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Originally Posted by peterlngh View Post
Hi, Randy.

From what I have read the scale aerobatic gliders like the Swift and Fox sacrifice quite a bit of thermal soaring performance for not a great deal more aerobatic performance. I have a 2 meter foam ST ASW 28 that soars very well and is quite aerobatic now that I have replaced the stock ailerons and dysfunctional internal linkages. Loops, rolls, spins, hammer heads, tail slides, and inverted flight are quite decent. When I want to soar I use my lightest battery and when I want energy retention I use the heavier ones but it will still soar in strong lift at a higher weight.

I'm almost certain that my next glider will be the Fly Fly DG 1000. It sounds like it's probably the best thermal machine in the Fly Fly 2.5 meter line. Will it soar as well as a lighter foamy? Probably not but I'm hopeful that it will soar if there's any lift at all and should be a little better aerobatic performer than a foamy due to a stiffer airframe. Plus, it's bigger and it's not foam.

I'm also considering getting an extra wing kit that I would add flaps to for camber control while soaring and then I would reinforce the other wing for aerobatics. I'm using my ASW 28 as a test mule to see if I think I can get by using just the ailerons for camber. It sounds like it can increase the natural propensity of a scale glider to drop a wing in a stall and that might get hairy. We have a big flying day scheduled for tomorrow and I'll let you know how it works.

There are also a few "warmliners" available that won't break the bank. Esprit Models has several with moderate wing loadings for example. I realize that they aren't scale but would probably perform a little better over all. They just wouldn't look quite as cool whistling across the field at ten feet!

Cheers!
I was kinda afraid of that, or should I say thinking that may be the case. I don't have slopes so fast highly acro slope soaring is out. And as of today I'm not intending on anything too high stress in the acro dept. Just the normal loops. rolls, snap rolls, inverted loops, hammer heads, that kind of stuff.

I do indeed really like the DG1000 myself. Any experience or opinion on it's flight envelope? Sure looks pretty with those swept wingtips.

thanks
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Old Jun 07, 2013, 08:14 PM
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Originally Posted by ask21flyer View Post
i my self have just been through this decision my self, i ended up going with the asw 28 2.5m, not exactly a thermal ship but i do like the scale and i will be doing some slope as well, the condor evo 3m i think would be a good all rounder in this category, the pic shows the 2 side by side
Nice sailplanes. I especially like the Condor. How do the perform? Thermal well?

Sold mild acrobatics?

thanks
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Old Jun 07, 2013, 08:21 PM
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Hi again.

In general terms; A semi symmetrical airfoil will have a lower lift coefficient than a flat bottom or under cambered airfoil. Flying Foam has a very basic comparison that might come in handy.

https://www.flyingfoam.com/content/w...should-i-use-0

Where things get complicated is comparing the lift coefficient to the lift to drag ratio (L/D). In very general terms, again, a plane with a heavier wing loading will usually go for a higher L/D. One trades pure floating ability for the ability to cover more ground, penetrate in stronger winds, aerobatic ability, and pure speed. (NOTE: One would think that an under cambered airfoil wouldn't fly inverted worth a damn but my Specter flies fairly well inverted. I don't pretend to really understand the math.)

Many modern glider airfoils use a very thin wing section with an under cambered surface in hopes of a greater speed range and more versatility. Using my Specter 1800 as an example again; it has a thin airfoil with under camber. It will slow down in lift, especially with added camber by drooping the ailerons, but won't match a thick flat bottom airfoil like on a Calypso for pure floating ability. On the other hand; I can cover a lot more ground and find the best thermals while the Calypso is still struggling to make it's first search up wind.

The EP 205 airfoil on my ASW 28 is semi symmetrical and actually flies very much like the Specter with a similar wing loading.

Cheers!
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Old Jun 07, 2013, 08:25 PM
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P.S.

I haven't flown a DG 1000 but it should perform fairly well compared to most of the others in the Fly Fly line. The reviews I've seen are quite positive and it has the lowest flying weight among the ones of the same size.

Edit: I mean the DG 1000 should perform better than the similar scale sailplanes.
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Old Jun 08, 2013, 12:09 AM
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For what it's worth, my friend has a Fox ST. He's isn't that happy with it. I've seen it fly and it's a brick as far as getting slope or thermal. She will get both, just not very well. there is also a terrible tip stall if she is allowed to slow. seems to always catch my friend when she is low too. He is a very good pilot and this is the main reason he has a love-hate relationship with her. Not one I would consider myself after seeing this one fly. Price is okay and she will fly inverted and sport fairly well but not much else to offer. Got to be a better option than the Fox.
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Old Jun 09, 2013, 10:57 AM
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Quote from Peter : Many modern glider airfoils use a very thin wing section with an under cambered surface in hopes of a greater speed range and more versatility. Using my Specter 1800 as an example again; it has a thin airfoil with under camber. It will slow down in lift, especially with added camber by drooping the ailerons, but won't match a thick flat bottom airfoil like on a Calypso for pure floating ability. On the other hand; I can cover a lot more ground and find the best thermals while the Calypso is still struggling to make it's first search up wind.

The EP 205 airfoil on my ASW 28 is semi symmetrical and actually flies very much like the Specter with a similar wing loading.

This DOES get complicated!!! Does it not!!! We all want our cake and eat it too!! Do we not!!
We want aerobatic capability AND good soaring , good floating etc!! Well,,, if your willing to spend some money,, you HAVE to go BIGGER and or more hi tech ( hollow molded wings )
Some of the bigger 3+ meter molded ships have incredible speed ranges ( using trailing edge camber ) and are EXTREMELY aerobatic ,,, the hollow molded wings give you the stiffness and airfoil fidelity to give performance that NO foam wing can even come close too. ,,,, I don't know what your budget is,,, but if you REALLY want something that has extreme speed range very good thermalling AND is around 2.5 meters,, at Soaring USA you might look at the NAN Orion . 95 in WS hollow molded at $650 for airframe,, sounds like ALOT,, but actually very good deal for something like that,,, it can be set up with a fairly inexpensive outrunner running on 3S for an AUW of around 50oz and Wingloading around 10oz/sqft,,, this plane IS what your looking for,,,, BUT are you willing to spend that much.
Go to Soaring USA s web site and watch the video of it,, quite impressive
Looks like I was wrong,,, its only $600,,, here's the link,, I've seen one of these in person,, very very impressive and soars quite well

http://www.soaringusa.com/Orion-2.4-E-Carbon.html

Ps edit : now you've got ME thinking again about getting an Orion!! There's toooo many good planes out there!!!!
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Old Jun 09, 2013, 11:11 AM
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Another less expensive choice in the bigger is better category is the E Flite mystique,, I've flown one ( until it crashed :-(,,, go to my blog ) it is very aerobatic has a speed range from about 20 mph to 95 mph will float almost as good as a radian with some trailing edge camber,,, but cause the wing is all wood,, just be careful about extreme direction changes at speed,, also your gona Havta be willing to fix its flexing pushrod system ( no big deal )
Go to the mystique thread here :
http://www.rcgroups.com/forums/showt...16172&page=166

Ps edit : ooooops!!! I didn't see your budget posted in very first post,, sorry!!!
All I can say is ,,,, eventually if you REALLY want GOOD soaring,, and I mean GOOD soaring AND good speed range , AND good handling AND aerobatics,,,, you'll have to find a way to increase your budget a tad and try one of the above mentioned planes,, and if you ever see one of those two planes in the hands of a good pilot ( to see their full potential ) you'll NEVER look at foam the same way again
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Old Jun 09, 2013, 11:28 AM
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Hi Chris:

Sport would be fine, IF the payoff is there. IE, it does what a scale ship won't. Do you have one in mind? Please share.
In general, sport planes will fly better than scale (particularly if you want to stretch the window of what one plane will do). They are designed to be efficient at the size they are. As soon as you start scaling a full-size design down, you run into limitations in flight behaviour. Generally, the answer to that is to go as big as possible with scale models, and the "numbers" will start working better for you. This is why you see so many huge scalies (up to 10 - 11m wingspan): they just fly better. When you scale a modern glass ship down to less than 4m, the wings end up with an extremely high aspect ratio, and that limits the ability of the wing to generate lift in a wide range of conditions. A sport glider will be way more efficient (I'm generalising here): just choose any one within your price bracket, and I can assure you that, apart from decent thermalling, they will do all the aerobatics you want to do. Possibly the Mystique is a good bet (I have't flown one, so I can't be sure)?

Chris
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