Nostalgia vs. modern built-up kits?

[chlee]

Hi all,

I've never flown one of these older kits like the Windfree, BoT, Mirage, Cumic or Aquila, but understand that some of them were quite serious contest-winners in their time. They would not likely stand a chance today against, say, a Bubble Dancer. But I'm wondering how well these flat-bottom Nostalgia ships fly against more comparable Sovereigns, Lil Birds and Chrysali, assuming that flying skill is fixed.

The reason I'm asking is that many of these Nostalgia designs are now available as laser-cut short kits for quite reasonable prices. (And I'm a cheap grad student :) ) So, all you experienced flyers out there: how good is a Windfree vs. a Lil Bird, or a Mirage vs. a Majestic, etc.?

-Chung

[Ollie]

The Cumic, Mirage and BOT have airfoils that are not flat on the bottom all the way to the leading edge like the Windfree and Aquila. The Cumic, BOT and Mirage will penetrate better at the same wing loading. The Mirage has the lightest wing loading and will come closest to the tight turning and weak lift working ability of the BD. None of them will come close to the spar strength and zoom launching ability of the BD. The Windfree, Aquila and Mirage have the weakest wings. Of the five that you mention, I would pick the BOT design and build it from scratch or be prepared to at least replace any bad balsa in the kit. Ray Hayes' new Skybird is a bit bigger than the BOT, has a better airfoil and will be a quality kit with good wood and laser cut parts. It would be a top choice and should be available soon.

[fprintf]

Chung, I echo your question for my own knowledge - will the BoT or nostalgia ships fly better, given enough skills to fly them, than the more modern, but smaller, birds?

I would note that the "modern" built up machines you listed are 2 meter designs. There has to be some thermaling advantage due to the size and wing loading of the nostalgia ships, so this is really not exactly an equal playing field. Perhaps it is better to compare modern built up standard class machines with the nostalgia versions, or the Sovereigns versus the Spirits and Gentle Lady's.

Just thinking out loud, and in type...

(note: I post this in the full knowledge that I'll be building a Sovereign first, and then moving on to a Big Bird or Sky Bird as building skills, flying skills, field size, time and money allow, so the answer is for future knowledge only)

[fledge]

the strength of the new gliders has really improved with the new building materials but im not sure that the performance is a whole lot better
im sure that there sink rate has improved because of lighter materials but i think a lot of these old kits are great birds!

i think it would be real eazy to assume that gliders have gotten a lot better but i think you will find that each glider has its good and bad features
i love these old bent wing gliders and in some cases i think they will really shine

i like to compare them with old sailboats,,,fast boats usually dont like rough water,slower boats are built for rough water there is no perfect design for all conditions.


gentle lady is a perfect example;; its won all kinds of events and somedays it will beat out the best of them just simply because it has an unreal sink rate!



call me old fashion but still think that the aquila,sagitta are some of the nices gliders to fly


also; have the times gotten longer for thermal duration tasks??? if so that would prove the newer designs are performing better,,,i can still stay in the air just as long as anyone else?????

fledge

[BMatthews]

If you want to compare these older designs to today's molded stuff then there is no comparison. But if you're comparing them to truly built up modern stuff then I doubt if there is much advantage to most of the modern stuff compared to the best of the past decade.

But be sure you're comparing apples to apples and not to cumquats... :D The Windfree was a floater first and foremost. Compare it to a Gentle Lady or some of the new trainers but don't even think about comparing it to the new ships. The Aquila was better but even it used an airfoil that was more concerned with thermals than with penetration.

The BoT, Cumic and Saggita all came out near the peak of the polyhedral contest designs. These, and others like them, came out at a time when we had realized that it was just as important to be able to speed around as it was to thermal. The standards of performance for speed and thermaling that this generation set is still valid and in use in today's designs from what I've seen.

The only real advantage the new ones have is their use of composites in the spars to allow crazy fast and hard launches.

It's been shown time and time again that when we build our models with open bays and film covering we loose much of the airfoil's promise. So I'd be very surprised if the new designs are delivering any more than the old ones in pratical terms of airfoil performance. The trend away from molded or all sheeted designs to the "new" :rolleyes: open bay ARF types is actually a step back.

But life is all about compromises. Many people will find that the lighter wings of these new ships will be easier to fly and to find lift. So in balance we get a performance increase at the expense of the speed range. Just more pilot friendly.

Mark Drela (Gad, I think I've been brainwashed into being his unknown PR guy... :D ) impressed me a lot with his work towards designing a practical airfoil that can be built accuratley in balsa and that accepted the realities of open bay construction. This airfoil is used on the Allegro Lite and E-Lite with, apparently, excellent results. Subbing in that airfoil on many of the older planforms would probably give them a big boost in performance.

Hey, just because it's new doesn't mean it's better. Surely politicians have taught us THAT...:D

[chlee]

This is a very helpful discussion. From what you all have said, it seems that a key feature is the D-tube with faster "semi-symmetrical" airfoils, like the E-205 or S3021.

I suppose, though, much fun can still be had with a $60 lasercut Windfree or Mirage -- if you like launching off of a high start and floating on mild days. ...And much fun could also be had by scratch-building a BoT with sheeted AG-34 airfoils and carbon spar caps.

Hmmm.... :)

- Chung

[BMatthews]

Oh, very much so chlee, I agree 100%. As long as it's not windy I love flying slow floaters. Nothing brings back memories of watching A-2's on a calm evening like a floater.

I've got a gull winged semi scale in mind for a sport glider that's right up this alley. Its a Ted Evan's design called, surprise surprise, the Gull. Very pretty and old world'ish.

Now if a few more people like Mark(aka Dr Drela when he's good to us... :D) would just put a little more effort into designinig flat lower surface rear run airfoils for practical built up contstruction the world would be a better place... :D

I may just have to fire up X-foil myself....

[schrederman]

I tried but couldn't stay out of this one. The Legionair series of sailplane designed on the early '70's is a contender. Ray Hayes at Skybench will be offering these soon. Check the results from this years Mid-South, and you'll find that the thin wing, flat bottom, built up Legionair 140 was 3rd in RES, and more importantly, in the realm of mouldies, 8th on Saturday in open class out of about 60. Of course, this wasn't stock as from the 70's, but was modified to take the winch launch and make the most of it. It was a nostalgia legal model, though, with the original wing planform and airfoil. I unfortunately lost it to a receiver failure in October. A new one is under way and my new, totally stock 100" version just flew about a week ago. Man is it LIGHT. While some brag about a BD being able to be hand-launched into thermals and specking out, I was doing that in '78 with a 100" Legionair. Try one...you'll like it!

Jack Womack:D

[BMatthews]

I have two all time fav's from the NOS era. The Grand Esprit and the Gaggler.

The Gaggler especially had the look of an A-2 Nordic in a radio control model. I've got the plans so perhaps one day....

And then there's the Grand Esprit if you don't mind square wingtips.... :D

http://www.dchobby.com/Airtronics/Photos/gel.jpg

[Mark Miller]

Hey, These are all great designs and just because something is old and maybe has a flexi wing doesn't mean it can't be fun to fly. I usually fly a Grand Esprit in Nostalgia and I think it is the most comfortable flying model I have. I also have one of my Mirage short kits and it is great in light air and flies like a big HLG. Don't forget the Mistral 3 meter either. Not nostalgis legal but a great building and flying ship. To my way of thinking as long as you take advantage of a designs strengths and fly it within it's limitations it will reward you. A mirage will never launch like a Bubble Dancer but it has a common design philosophy and have that light nimble feel.

BTW, the Bubble Dancer kit is coming along well. I should be making the first fuselage mold this weekend. Here is a pic of the plug.

Mark Miller
http://www.isthmusmodels.com

[Tim Jonas]

All time fav is the Aquila standard. Flew it in 1977, and loved it, right up until it made a hole in the ground. Bought one last year on Ebay, and I'll be building it shortly.