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Old Sep 29, 2012, 07:48 PM
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Evansville, WI
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Swap meet score, what is it?

I went to a swap meet this weekend, a regular car swap, not an RC swap. I happened across this glider. For the grand sum of $30, I got the glider, three wings, a box of misc parts from a Sig Riser, and a positively ancient 2ch Futaba Attack. I have no idea what this glider is(it's definitely not the Sig Riser who's box and misc parts were included). It's all balsa and monokote, 2M span, about 44" nose to tail. Two of the wings are the same and seem to fit, the third green/yellow wing I think is off a different plane. I've got some questions.

First what is it? Can anyone ID this thing? How will it fly, is it worth messing around with, or is it just a flop from the past?

Second, how do I get it off the ground? I'd call myself an intermediate glider pilot, but my other sailplanes are powered. I don't have a bungee, high start, winch, or slope to fly from, and there is no tow hook on the plane. What's the easiest/cheapest way to get it in the air?

Third(really 2.5), If I can't come up with a way to launch it unpowered, what kind of powerset will I need for it? I don't need a rocket ship, just enough power to keep me in the air when there's no lift. What prop size and what wattage will I need?

Thanks for the help
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Old Sep 29, 2012, 08:10 PM
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Jeff...what you have is one of Goldberg's last gliders...It is a wonderful glider but not strong enough for launch on a 12 v.system. It will be a good slope glider or you can get a bungee launch system and use it.
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Old Sep 29, 2012, 08:12 PM
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Looks a whole lot like a Sophisticated Lady.
http://www.hobbyclub.com/images/gpma...icatedLady.jpg
That means it's much like a Gentle Lady except for a weak tail (t-tails tend to break easily) and the brutally pointed nose which might hurt someone. The GL is aptly named as it is handles nicely and floats well. But you probably know that. By all means fly it.

If you have a really good arm, you can throw it. I've seen a skilled pilot with a strong arm fly a Gentle Lady as a hand launch glider. It's easy to add a tow hook. Just put a piece of aircraft ply inside the bottom, slightly ahead of the c.g. Bend a threaded cup hook into an l shape and screw into a hole in the ply, maybe an inch ahead of the c.g. You can try moving it back maybe a quarter of an inch at a time for higher launches. Suggest using a high start that just barely fits in your field when stretched. Aerofoam makes some nice ones called Hosemonsters. A cheaper option might be the Dynaflite "Heavy Duty" high start, which is actually only strong enough for two meter gliders like this one.

If everything is really flat around you, perhaps you could slope it in front of that barn which shows up on Google Maps when you look up Evansville. It really doesn't take much if the area in front of the slope is flat for a long way upwind. I've sloped a two foot (or less) bump in the sand in a light wind coming off the ocean. Needs a light glider, but this one probably is.

I think a rule of thumb is 75 watts per lb. That should give you enough for a reasonably strong climb. That would be about 125 watts. Anything recommended for a light two meter glider ought to work just fine. I've seen a slightly lighter two meter (the Allegro Lite) climb just fine with a Speed 400 ferrite motor and a 6 inch Graupner folder, but it had to be kept moving, and you might spend a couple of minutes getting to a few hundred feet. The power system from a Radian would be manageable but give you a lot more than you need. If it was me, I think I might try a 7 inch prop of medium pitch (4 to 6 inches, maybe?) and a motor that could put 125 watts into it.

I've seen power pods that can be rubber banded on top of the wing, but I don't know how well they work.

Beware of the single conversion receiver that originally came with the Attack, unless you're flying in the middle of nowhere, with no one else on 72 mHz. It's narrow band and all, but there are various problems. Particularly with two radios 23 channels apart. I'm not expert, but I hate crashes.
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Old Sep 29, 2012, 08:15 PM
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P.S. People think a glider isn't winchable unless you can stomp the pedal without breaking it. We've actually been using essentially the same 12V winches (with 6V winds) as long as I've been in the hobby. Back when we didn't EXPECT indestructible wings, we launched stuff like this on winches as a matter of course. Just practice your tapping before launching. Little quick taps a couple of times per second. Or you may be able to do it once per second. Of course, if the workmanship is poor, you may find out.
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Old Sep 30, 2012, 12:19 AM
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Quote:
Originally Posted by Bugman Jeff View Post
Second, how do I get it off the ground? I'd call myself an intermediate glider pilot, but my other sailplanes are powered. I don't have a bungee, high start, winch, or slope to fly from, and there is no tow hook on the plane. What's the easiest/cheapest way to get it in the air?

Thanks for the help
Jeff, You don't need much to get this plane into the air. A Dynaflight standard hi-start would launch this just fine and that is probably the weakest hi-start out there. I use this hi-start to launch my 2M Sig Riser and it does just fine. Gentle, easy launch to altitude and float off the hook, costs around $60. Yes there are stronger, more expensive hi-starts out there but this one will get the job done.

http://www3.towerhobbies.com/cgi-bin...P?I=LXYXK4&P=8

Good score there. The green and yellow wing looks like a Riser wing.

Wayne
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Old Sep 30, 2012, 04:23 PM
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You got yourself a great deal.

The nose on that bird is a killer but shaped just right for an electric conversion.
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Old Sep 30, 2012, 09:23 PM
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Thanks for the info. I don't think this plane had ever been flown. I had to rework the elevator linkage to get any down elevator deflection. I also think the canopy might be from another plane. It matches the pics of the SL I've seen, but it doesn't fit this plane. I got the elevator sorted out, and reworked the canopy enough to get it to (sorta) fit and took it out. I'll probably rework the whole elevator linkage, I just don't like how it's done and it doesn't operate very smoothly. I also swapped in a new Rx, so I can use my 9C. I didn't even want to attempt using the Attack, I don't trust that I wouldn't dumb thumb it into the ground with the elevator on the left stick.

It was kinda windy, and not real thermally today, but I found a temporary solution to getting it in the air. I have a 100' grain bin on the farm with an external staircase. It's a whole lot of steep steps, but it they get you there. I got to the top, and gave it a throw. Wow does this plane glide well. I don't know what I was expecting, but it really floats. On a nice day, I might even be able to hand launch thermal it.

I might try and make a high start, but I'm probably going to go electric. With the amount of ballast this plane needs, I can probably put in a small brushless system and be at the same, if not less, weight
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Old Oct 01, 2012, 12:28 AM
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The problem with electric rc gliders is what might be called a "moral hazard". It's really easy to turn on the motor instead of working hard to catch that low thermal, or, after a while, any thermal. Not a problem with the grain bin launch, I'm sure! If you go electric, make a commitment not to turn on the motor again unless you are down to 10 feet or so. Or if you will be in the trees otherwise, but in that case beat yourself up after the flight or you will be headed down the slippery slope.
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Old Oct 01, 2012, 05:19 AM
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I prefer pure gliders but have no problem with electric gliders, I have several and enjoy them a lot.

75 watts per pound of all up weight is fine for sport soaring. I prefer a stronger climb, so 100 per pound is more my preference.. Anywhere in that range will be fine.

Keep the battery as light as possible. The 1300 mah in my Radian only gives me about 4 minutes of full throttle time. I usually get about an hour per pack.
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Old Oct 09, 2012, 09:45 PM
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I went back and fourth and waffled for a few weeks, and I've made a choice. I'm going to build a high start. I can't justify the cost of a commercial high start, but I found a deal on enough silicone tubing to build one. It necessarily has to be a bit short because the field I fly from isn't all that big. I've got 40' of tubing, and I'll probably add 40' of line. I have around $20 in it, so if it doesn't work, I'm not out much. It also occurred to me that with a high start, I can build another glider from the Riser pieces that came in the bundle
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Old Oct 09, 2012, 10:16 PM
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String is cheap, I'd use 120 feet or so.
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Old Oct 09, 2012, 10:26 PM
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GliderJim is right, the string to relaxed tubing ratio is usually around 3:1. You will get much better launches this way.

Wayne
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Old Oct 09, 2012, 11:34 PM
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I appreciate the input. I know a longer string would be better and I've got a whole spool of 30# test, I just don't have the space for that much length on the field I fly from.
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Old Oct 10, 2012, 10:30 PM
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Jeff:
Given that you have a 100 foot grain grain bin available, you may have a launch option that none of the rest of us have. What if you put a pulley on a stick out over the edge of the top of the grain bin? Then take 300 feet of fishing line, run it through the pulley, put a 5 lb weight on one end, and the hi start parachute on the other end. Use it like a high start. Seems like it would be much like a high start except it would pull the same force the whole way up and it would pull UP. If it worked out, maybe you could use more weight and more line.

I just made this up, but it seems like it might be viable, and very easy to do.
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Old Oct 10, 2012, 10:48 PM
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Now I'm wishing I had a 100' grain bin and a pulley!

Just think, if the tow hook is in the usual location, the plane would be "past vertical" until it got close to 100' high. Only then would the string be parallel to the ground and the plane in a "normal" launch attitude. You probably wouldn't want to come off the line until you were well past 100', otherwise it would be like a pop off on a regular launch. Hopefully you get there before it get's pulled through the turnaround pulley.

Interesting.

Jim
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