kit bashing a Gentle Lady?

[ozmo01]

Anyone modify a Gentle Lady or other 2m kit to a higher performance airfoil?
I would guess all kinds of spar mods have been done for winch etc.

[jtlsf5]

A number of years ago (late 80's) Walt Good, one of the deacons of RC, modified a Gentle Lady by putting a Selig 4061 airfoil on it, along with a multicomponent spar. This little gem rewarded Walt by taking a full power launch and flying in conditions that most Gentle Lady's would be kept at home.

Also in the early 80's there were people taking Sagitta 900s and removing main rib bays to end up with a 2M ship with more square inches and a lower aspect ratio than normal 2M's. Some of these launched very well.

JT

[histarter]

Anyone modify a Gentle Lady or other 2m kit to a higher performance airfoil?
I would guess all kinds of spar mods have been done for winch etc.
The GL design is quite good as far a configuration is concerned. Structure improvement, like wider sheeting all the way to the wing tip, adding two 3/32 spars to the fin for a diamond profile and stiffness, and making the stab with a 3/32 spar into a 1/2 diamond (negitive) for stiffness is about the best that one can do for the GL.
Winch operation is too intense with the heavy lines etc. so profile refinement should not be a concern, while limiting a reinforced GL to high start only yields hours of delightfull entertainment. At 30 ounces + rtf the speed range of Carl Goldberg's FB is just about right. ;)

[jtlsf5]

The GL design is quite good as far a configuration is concerned. Structure improvement, like wider sheeting all the way to the wing tip, adding two 3/32 spars to the fin for a diamond profile and stiffness, and making the stab with a 3/32 spar into a 1/2 diamond (negitive) for stiffness is about the best that one can do for the GL.
Winch operation is too intense with the heavy lines etc. so profile refinement should not be a concern, while limiting a reinforced GL to high start only yields hours of delightfull entertainment. At 30 ounces + rtf the speed range of Carl Goldberg's FB is just about right. ;)

Read the above. You're experience is a too limited to be such an "authority" if you really believe your minimalist modifications are the best that can be done. Clearly others have more vision and are more open to try things than you seem to be. You should do more and talk (type) less.
JT

[cosmicpossum]

My goodness. Was that comment really necessary?

[histarter]

Read the above. You're experience is a too limited to be such an "authority" if you really believe your minimalist modifications are the best that can be done. Clearly others have more vision and are more open to try things than you seem to be. You should do more and talk (type) less.
JT
Wow, after 30 years of flying about 12 modifications of GLs - that actually placed in the early TNTs, TD events for unlimited sailplanes, I find it interesting that you are more experienced, and have a vaster imagination in modifying a $30 kit! Mine flew F3B in Blakesburg Iowa doing the traps in 14.6. (Profile was tweaked a bit with Phillips). When the winches got over 50 lbs tension, I stopped with this stupidity - and the lone surviving GL is still flying.

Now if you can make one into a better F3B machine for less than the price of 2 kits, I will blow the dust off one in my stockpile, and build it your way for a learning adventure. I sit hear all ears!!

[lincoln]

I had a Gentle Lady on which I substituted a 2 meter wing of similar proportions (perhaps a bit higher AR, but I'm not sure so many years later) which nominally had an Eppler 205 airfoil. I really liked it, it was much faster, handled fine, etc.. Launched just fine on a winch, too. A Ford starter motor winch. The kind that are too powerful to be legal in F3B. Just had to tap a bit. Not as much as you have to tap with a GL, which goes up fine on the winch too, although perhaps not as high or fast.

[ozmo01]

Play nice or I'll take my ball and go home :D ;) ;)


DON"T FEED THE TROLLS PLEASE

[ozmo01]

Ok so there is lots of options for airfoil choices and I have set in mind.
I also have read up on beefing up spars. So at this point has anyone minimalized the fuse of Gentle Lady or other wood glider. I think of this is an opportunity to get more performance ( fun) out of a $50.00 kit. :D

I already have a finished stock GL. This is for fun.

[histarter]

I had a Gentle Lady on which I substituted a 2 meter wing of similar proportions (perhaps a bit higher AR, but I'm not sure so many years later) which nominally had an Eppler 205 airfoil. I really liked it, it was much faster, handled fine, etc.. Launched just fine on a winch, too. A Ford starter motor winch. The kind that are too powerful to be legal in F3B. Just had to tap a bit. Not as much as you have to tap with a GL, which goes up fine on the winch too, although perhaps not as high or fast.
The Ford Long Shaft Starter motor winch is the one I used with my GLs at the time. 33 lb tension, step hard and zoom my (reinforced) GL - was my tactic! This antique Ford feild motor was weak compared to today's PM motors with rare earth magnets, and low milliohm windings - that can stall at 6x run torque. (more than 100 lbs tension). Yes, I am the cowardly lion because I cannot tap that cautiously.

[histarter]

jtlsf5 I am totally excited about your technical synopsis on the super GL. I guess I should give you some time to gather up your data.

[lincoln]

The Ford Long Shaft Starter motor winch is the one I used with my GLs at the time. 33 lb tension, step hard and zoom my (reinforced) GL - was my tactic! This antique Ford feild motor was weak compared to today's PM motors with rare earth magnets, and low milliohm windings - that can stall at 6x run torque. (more than 100 lbs tension). Yes, I am the cowardly lion because I cannot tap that cautiously.
Who is using rare earth magnets in their winches? A 6V wind (forgot to mention that) Ford motor with a 12V battery is quite powerful. Probably too powerful for it's own good, I've seen one smoke. I agree that the 12V wind is gentler. The 6V wind is powerful enough to zoom a couple of hundred feet, I think. The 12V wind is adequate to launch quite large gliders but not as thrilling.

I have never seen rare earth magnets in winch motors, and I am a member of a large RC club with many sailplane flyers including a number of avid contest flyers. There's no need for the rare earth magnets unless you need a LIGHTER winch motor. Come to think of it, I could use one, so I'd love to know more.

[lincoln]

Ok so there is lots of options for airfoil choices and I have set in mind.
I also have read up on beefing up spars. So at this point has anyone minimalized the fuse of Gentle Lady or other wood glider. I think of this is an opportunity to get more performance ( fun) out of a $50.00 kit. :D

I already have a finished stock GL. This is for fun.
If you're going to replace the fuse AND the wing, why not build something else? The airfoil I understand.

A guy in our club used to make 1/32" ply fuses which were kind of a U cross section. I don't know what he capped the top with as I didn't actually see one. People have been using fishing poles for skinny rear fuses for a long time.

I would just steal the airfoil from a Bubble Dancer or Allegro Lite. If not a Drela foil, I'd favor the S3021.

[jtlsf5]

...

[jtlsf5]

Wow, after 30 years of flying about 12 modifications of GLs - that actually placed in the early TNTs, TD events for unlimited sailplanes, I find it interesting that you are more experienced, and have a vaster imagination in modifying a $30 kit! Mine flew F3B in Blakesburg Iowa doing the traps in 14.6. (Profile was tweaked a bit with Phillips). When the winches got over 50 lbs tension, I stopped with this stupidity - and the lone surviving GL is still flying.

Now if you can make one into a better F3B machine for less than the price of 2 kits, I will blow the dust off one in my stockpile, and build it your way for a learning adventure. I sit hear all ears!!


Wow, now I'm impressed!! 30 years, 12 modified Gentle Lady's and the best you can do is a little sheeting and a couple of ribs in the tail. You're a pretty skilled guy.

Still got your 14.6 second GL? Bring it to Muncie this year and fly it in the Nats F3B event. I know our future USA team members would be glad to benefit from your wealth of knowledge and experience. I'll be on pins and needles too.

Joust on, Don Quixote.

[TLyttle]

I'm thankful that it is only once; please go back up to your mountaintop and consider the universe, clearly we the unwashed are not worthy of your ministrations...

I D-tubed my GL, plenty strong enough, changed the airfoil to roughly E193, made it one piece, and installed shear webs. I also replaced the sides and half the bottom with 1/32 ply, resists tentpegging just fine (do you have to ask?)

I have tried the stab at different heights, mostly to keep it out of the grass (or rocks, in my case), seemed to change nothing.

My GL is almost 20 years old, and has many'many hours on it, both thermal and slope. Good ol' GL, Carl sure left us a legacy.

[SmokinJoe101]

Ok so there is lots of options for airfoil choices and I have set in mind.
I also have read up on beefing up spars. So at this point has anyone minimalized the fuse of Gentle Lady or other wood glider. I think of this is an opportunity to get more performance ( fun) out of a $50.00 kit. :D

I already have a finished stock GL. This is for fun.

Spend another $25 and build a BOT :eek: no matter what you do to the GL

it's still a GL :cool:

sj

[histarter]

Who is using rare earth magnets in their winches? A 6V wind (forgot to mention that) Ford motor with a 12V battery is quite powerful. Probably too powerful for it's own good, I've seen one smoke. I agree that the 12V wind is gentler. The 6V wind is powerful enough to zoom a couple of hundred feet, I think. The 12V wind is adequate to launch quite large gliders but not as thrilling.

I have never seen rare earth magnets in winch motors, and I am a member of a large RC club with many sailplane flyers including a number of avid contest flyers. There's no need for the rare earth magnets unless you need a LIGHTER winch motor. Come to think of it, I could use one, so I'd love to know more.
Never did a 6 volt wind on a Ford motor, and at 4 times the wattage, I really don't clasify that as "state of art."

Check out Rham winches. That is state of art.

On my Ford long shaft 6 volt starter (with unreliable 6 volt battery at the time), the DLSF insisted I tone it down for the majority of high start pilots. I added a program switch that changed windings from shunt to series, and tension was a smidgeon more than a highstart. Everyone was happy! GLs competed with Sailaires at a flip of the switch. :)

[jtlsf5]

[QUOTE=histarter]Check out Rham winches. That is state of art.[QUOTE]

Yet another gem here. 15 year old winch technology, and I recall hearing that Cy Rahm stopped making winches at least 4-5 years ago. But you still consider this is state of the art. Care to share with all interested parties where they can buy their own new Rahm winch?

If it isn't available, it is no longer state of the art, just a good piece of history. Something else becomes state of the art, because art moves on.

Fly more, talk less.

[histarter]

[QUOTE=histarter]Check out Rham winches. That is state of art.[QUOTE]

Yet another gem here. 15 year old winch technology, and I recall hearing that Cy Rahm stopped making winches at least 4-5 years ago. But you still consider this is state of the art. Care to share with all interested parties where they can buy their own new Rahm winch?
Just like the Legionair, the Rham was a pacesetter. Marketing is the number one priority in America, and not engineering. If one company dies off, another picks it up with their (Chinese) copy.
If it isn't available, it is no longer state of the art, just a good piece of history. Something else becomes state of the art, because art moves on.
That is your cerebral problem. Stradivarius, Yamaha Concert pianos, SR 71 Blackbird, all happen to be a lot older equipment, yet they are still state of Art. State of art does not mean the "winner of some kind of competition"
Fly more, talk less.
Your lack of loyalty to anything of quality and good engineering is breathtaking! :rolleyes:

[jtlsf5]

Your lack of loyalty to anything of quality and good engineering is breathtaking!

And perhaps when you quit living in the past and get a clue, intelligent discussion can result. As it stands, your stagnant view of reality is truly awe inspiring and laughable.

[TLyttle]

Oh, yawn.... is he still here? Wake me when he leaves...

[ozmo01]

if you keep putting milk in the dish on the porch the stray won't leave :eek:

FYI I am building a BB xl 118'' with spoilers and without serious mods.

Kit bashing a GL is just for fun. and at $50.00 for a kit its cheap fun.
Also because it is a fast to build kit even if you bash it some.

As far as using Drela air foils...well that is what I had in mind :D
I would sheet it further back ( deeper D tube) and tip to tip.
I have some CF for top and bottom of spar tip to tip. and would wrap it with kevlar thread. Had not decided to add a polyhedral set up like a Drela wing or keep the GL look. It would be fun to show up at a contest with it looking like a stock GL. Except I already Blabbed here! :(
Fuse mods would be to minimize size / wt to just fit around the gear I would use. possibly stiffen up the main tail spars. use a little CF to boost the fuse strength back by the tail and to allow for generous rounding of the corners.
Then cover it to look like the GL on the box ;) ;)
I will do a set of spoilers in any event to fly RES.. ?? big flat one in the middle ?? or keep the disguise?? :)

Any way you cut it it is all fun!

[histarter]

if you keep putting milk in the dish on the porch the stray won't leave :eek:

FYI I am building a BB xl 118'' with spoilers and without serious mods.

Kit bashing a GL is just for fun. and at $50.00 for a kit its cheap fun.
Also because it is a fast to build kit even if you bash it some.

As far as using Drela air foils...well that is what I had in mind :D
I would sheet it further back ( deeper D tube) and tip to tip.
I have some CF for top and bottom of spar tip to tip. and would wrap it with kevlar thread. Had not decided to add a polyhedral set up like a Drela wing or keep the GL look. It would be fun to show up at a contest with it looking like a stock GL. Except I already Blabbed here! :(
Fuse mods would be to minimize size / wt to just fit around the gear I would use. possibly stiffen up the main tail spars. use a little CF to boost the fuse strength back by the tail and to allow for generous rounding of the corners.
Then cover it to look like the GL on the box ;) ;)
I will do a set of spoilers in any event to fly RES.. ?? big flat one in the middle ?? or keep the disguise?? :)

Any way you cut it it is all fun!
I see you being a lot more sophisticated than jtlsf5! He was unable to relate to the hop up adventure as yourself, and I have to admit your design prospect sounds better than my simple modifications. Guess I am too lazy for the intensity you are displaying, and simply enjoy the prospect of having a great HAM performer rather than a mini F3B. For the fun of it is the best reason in the world.

[ozmo01]

YUP
If were having fun its all good :)
the goal would be a glider that could handle a little more wind and be cheap and quick to build. RES is were I want to play.

[lincoln]

snip
Check out Rham winches. That is state of art.

snip
I would if I knew where to look. But I seriously doubt they use rare earth magnets. Perhaps I'm wrong.

[Curare]

heh, I tend to agree with most of the guys here.

You can't call it a GL if you change the planform, airfoil and fuselage can you?

Look its a pitts special that modified, and lengthened the tail, took the wings off put a zlin wing on!!!! nice Pitts isn't it?

Um er. what?



BLTGDPS!!!!

[histarter]

heh, I tend to agree with most of the guys here.

You can't call it a GL if you change the planform, airfoil and fuselage can you?

Look its a pitts special that modified, and lengthened the tail, took the wings off put a zlin wing on!!!! nice Pitts isn't it?

Um er. what?



BLTGDPS!!!!
My thoughts. The GL is a cute little floater that can be made into a compact thermal machine by stiffening and strengthening structure. The additional weight onto Goldberg's profile that can tollorate even higher loadings, makes the machine very effective (supported by statistics).
More exotic conversions really converts the fine design into something else.

[UnkyJack]

As far as using Drela air foils...well that is what I had in mind :D
I would sheet it further back ( deeper D tube) and tip to tip.
I have some CF for top and bottom of spar tip to tip. and would wrap it with kevlar thread. Had not decided to add a polyhedral set up like a Drela wing or keep the GL look. It would be fun to show up at a contest with it looking like a stock GL. Except I already Blabbed here! :(
Fuse mods would be to minimize size / wt to just fit around the gear I would use. possibly stiffen up the main tail spars. use a little CF to boost the fuse strength back by the tail and to allow for generous rounding of the corners.
Then cover it to look like the GL on the box ;) ;)
I will do a set of spoilers in any event to fly RES.. ?? big flat one in the middle ?? or keep the disguise?? :)
Cool mods. Definitely go with the "disguised" GL look. ;)

Jack

[Curare]

hehe, you know i did the same thing to a an old house of balsa 2 x 6, well sorta.

flew the 2 x 6, realised it had no penetration, so made a nice AG 36 wing for it.

It really moved out, and was nice to fly, till I realised the fuselage was holding me back.

Redid the fuselage as skiiiiiiny as possible and put some nice thin tailfeathers way out the back, the result was a new airplane. I called it the NIX becuase it was ten times as good as a 2x6 but contains zero parts. 2x6x10x0= 0


yes, I'm nerd, but it reiterates my point, A GL is a GL, if you bash it too much it's just not a GL anymore.

[Lance Prior]

I noticed CST has square carbon tubes now.

You could replace the stock wood spars with square carbon tubes for a stronger wing.

[ozmo01]

sure carbon spars would be killer but also expensive. I don't mind spending some, but on this project I would keep it simpler and cheaper just because a cheap airframe was part of the original idea. I would like this to stay simple to
help stimulate the interest of beginners but allow flying in some more wind
(and for me to be a little more competetive) but mostly just for the heck of it! :D

[lincoln]

If you want to stay with wood, and you don't mind going to two spar caps with a shear web, maple lets you get more of the strength further from the neutral axis.

[Curare]

D box it if you can, just add more sheet top and bottom on the leading edge, it'll give you a much stronger wing and a better airfoil profile.

Also a turbulator or two outboard will help as well, if you wanna keep it easy

[TLyttle]

Curare has it right; just D-tube the wing (don't neglect the shear webs) right out to the tips, that is as strong as you need to have a GL. As I said, mine is 20 years old, and wing flex or failure is never a problem.

[Fly2High]

Lincoln,
I always thought that strength to weight, spruce was the best. I could be wrong.

I like the idea of D tubing and adding carbon to the spars. My old GL only had one spar but the newer ones have two, top and bottom. If you gt one with only one, good luck.

On a bad crash (I cracked the fuse in three places where the shortest crack was 18" long!) I decided to try my first attempt at making a glass fuse. While I was at it, I also made it a V tail. Now it is a pod and boom with a V tail. The dimensions were all based on the original plans and I am still using the original wing. Looks pretty cool too and it still flies like a GL (unfortunately I am lousey with epoxy and it came out 34oz all up. - but it does handle wind much better!)

Frank

[sailhigh]

Going back to the original subject of this thread, kit bashing a GL, in my opinion the options are unlimited and I don't think all that can be done, has been done.
I'm a big fan of GL and my latest mod of the GL with ailerons has really given it a new persona. I simply eliminated the polyhedral and the washout and added ailerons with minor structural modifications. With the aileron and rudder mixed, it turn as tightly as before and has definitely improved in the top end of the speed envelop. For the past few years it's been my favorite inland slope flyer.

[lincoln]

Lincoln,
I always thought that strength to weight, spruce was the best. I could be wrong.

snip

Frank
Strength to weight is a funny thing. It depends on a lot of things. If you're just pulling on it, steel cable blows away spruce. But try to make a spar out of that! (or music wire, which is also wicked strong, even for the weight). You need something thick enough not to buckle, but thin enough that you can fit it in the right place. A heavier, equally strong, but thinner spar cap can be placed further from the "neutral axis". (Think of it as the center.) So in effect, it's a little like slicing a 2X4 the wide way (to get 1X 4's). If you glue the two 1X4's to a shear web so they're 4" deep on the outside, you've almost doubled the strength for almost the same weight. (Ok, think of a 2 X 4 as 2 X 4, I know it's really more like 1 1/2" X 3 1/2")

If you get thin enough and your shear web isn't good enough then the extra strength won't be usable because the part under compression will buckle.

The strongest wood spar for the weight might be a very fat one that would never fit in the wing, a balsa i-beam.

A 1/8 spruce stick, a 1/32" music wire, and a 5/16" balsa stick are all about the same weight. It's my guess the balsa stick will be strongest in bending, followed, I think, by the spruce and then the wire. The music wire will be maybe twice as strong as the spruce in tension, and I bet the balsa is the weakest.

I think you are right that the pounds per square inch at the beginning of permanent deformation, when divided by weight, will be higher for spruce than maple. But not by much. BTW, douglas fir is an excellent spar material that is almost as good as spruce on strength to weight and a little denser.

[ozmo01]

Wow
Thanks for all the great "food for thought ". Lots of great ideas. :)

[Lance Prior]

sure carbon spars would be killer but also expensive. I don't mind spending some, but on this project I would keep it simpler and cheaper just because a cheap airframe was part of the original idea. I would like this to stay simple to
help stimulate the interest of beginners but allow flying in some more wind
(and for me to be a little more competetive) but mostly just for the heck of it! :D
http://www.cstsales.com/carbon_square_tubes.html

Doesn’t look very expensive to me. :)

On another subject, if you want to use a thin Drela airfoil you are going to need carbon fiber.

The nice thing about using a Drela airfoil is he has some flat bottomed ones designed for wood construction and they perform pretty well.

[merlinmurph]

Here's what I'm doing with my Oly 2S, my first real sailplane build. Basically, you replace the top and bottom spar caps with a tapered carbon fiber and hard balsa laminate, an idea borrowed from the Allecro-Lite and Bubble Dancer. I've attached a short article written by a fellow CRRC clubmember that explains the process.

Also here's a thread (http://www.rcgroups.com/forums/showthread.php?t=808956) where some of this is discussed.

Murph

[ozmo01]

Merlinmurph: Yup those price are decent, thanks ...

dr -sprocket: Thanks....I think that kind of spar reinforcment would be great as I have a couple of packages of CF tow around.

[Rusty Joe]

Why the trash talk? Maybe we should give our old timers a little respect. Keep in mind you will be an old timer some day.Wow, now I'm impressed!! 30 years, 12 modified Gentle Lady's and the best you can do is a little sheeting and a couple of ribs in the tail. You're a pretty skilled guy.

Still got your 14.6 second GL? Bring it to Muncie this year and fly it in the Nats F3B event. I know our future USA team members would be glad to benefit from your wealth of knowledge and experience. I'll be on pins and needles too.

Joust on, Don Quixote.

[histarter]

Why the trash talk? Maybe we should give our old timers a little respect. Keep in mind you will be an old timer some day.
Thank you Rusty,
Unfortunately the soaring genius of today wants to convert the great GL design into a F3B machine, and cannot perceive that simply upgrading a good design (like the Windows they are using for this discussion) is a viable technique to extract the most out of the designers intent. Instead of better, they want perfection (that is unobtainable). Which one of us is the Don Quixote?