Vintage and old timer models Discuss nostalgic vintage aircraft

Goldberg "Sailplane"

Old 01-18-2007, 11:01 PM
  #1  
donjiskra
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Default Goldberg "Sailplane"

Jim is doing a beautiful job on his awesome "Sailplane" and is wondering how to install servos and receiver, since the 1940 plans, naturally didn't use R/C gear at that time.
Anyone have suggestions?
Thanks,
Don
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Old 01-18-2007, 11:18 PM
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AEAJR
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First you need to define what moveable surfaces you will have.

That looks like it might be a free flight glider. If so, it probably has plenty of dihedral in the wings, so you could set it up for Rudder/Elevator controls. Very common on sailplanes.

Depending on the balance of the plane, servos could be mounted in the tail or in the nose with control rods going to the back.

Can you post a photo of the fuselage?

Mini or micro servos should be fine.

How do you propose to fly it?

Hand launch?
Hi-start?
Winch?
Slope soaring?

Glad to help if I can.
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Old 01-18-2007, 11:20 PM
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Sky Sharkster
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Default Controlling the "Sailplane"?

Hi Don, Jim is doing a great job! The Goldberg Sailplane is one of the most beautiful models ever designed. Hope to see some flight shots!
I've converted a few O/Ters to R/C, my suggestion is to use hard balsa strip stock (3/16"-1/4" square) for the pushrods, with a short piece of "L" shaped threaded rod on the tail end, a "Z" bend of regular M.W. on the servo end, attached with thread + glue. This is lightweight, strong in compression/extension and looks "right' among all those sticks.
For the servos and R/X, I use a lightply frame, with 1/8" balsa side rails. It's mostly cut out, made slightly larger than the "hole" size and gets glued to a convenient stringer on each side. It's just behind the C.G., I leave a large open space in front for battery fore-and-aft shift until I get the C.G. right. The RX antenna can run through the fuselage, there's very little metal or F/G to interfere with the signal.
Although the elevator is fairly sensitive on these models, they need a good-sized rudder, like 40% of total vertical area and plenty of throw. I guess the large dihedral angle reduces the rudder effectiveness.
Last suggestion, cover it with "Transparent" covering, it would be a shame to hide all that work!
Good Luck!
Ron
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Old 01-19-2007, 04:19 PM
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Ed & Ron,
Thanks for your comments, they are appreciated.
Jim plans on 3 channels, no ailerons and wants to keep the servos inside.

The Goldberg "Sailplane" is a beautiful elliptical design and was originally designed for an ingition gasoline engine, which would have a short limited engine run to get up to altitude and then perform as a sailplane. I tried to talk him into electric motorization but he's into Giant Scale with glow engines. I sure wish he'd build one for me, as I'm strictly electric.

I'll pass your comments on to him.

Thanks,
Don
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Old 01-19-2007, 05:09 PM
  #5  
Cecil M Wethy
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Default Goldberg Sailplane Rc

When Comet kitted the Goldberg Sailplane, RC models
were being built. Comet kitted a 10 foot Goldberg
Clipper about this time. AMA [Pond] I believe has
the plan. The Goldberg Sailplane would have been
great for RC, but at the time the RC equipment
available was too large to fit in the fuselage. I still
have a Comet Sailplane kit from 1946, which was
priced at $4.95. Cecil
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Old 01-19-2007, 05:25 PM
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Cecil,
That's very informative. Times sure have made many significant changes in our hobby. I'm very excited to see Jim's "Sailplane" inflight.
He's an incredible builder, very meticulous and an excellent pilot.
I'll shoot some videos when it's airborn, later this soring.

BTW, want to sell your kit?

Don
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Old 01-20-2007, 02:36 AM
  #7  
AEAJR
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Servos of the size of Hitec HS-81s would probably meet your needs.

A micro receiver, such as the Hitec Electron 6 would work.

Hope that helps.
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Old 01-20-2007, 12:30 PM
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donjiskra
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Thanks Ed,
Good suggestions.
Don
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Old 01-20-2007, 10:28 PM
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Cecil M Wethy
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Default Goldberg sailplane

Don, I am not sure all of it is there. I have been a Goldberg fan since I was a kid. He was way ahead of his time in indoor, free flight and later RC.
I believe the kit would be worth more as a souvinir. I have a copyimg source that is very reasonal and can make you a copy if you want to
build one. I also have a 1/2 size plan [36"]. LMK if either of these insterest
you.
On the Comet 10 foot RC Clipper, Hal DeBolt put a article on it in MAN in
either 1991 or 2 from pictures and info I sent him. I have a copy here somewhere, the article was "Florida Clipper". It was powered with a
Forster "99". Cecil
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Old 01-22-2007, 09:40 PM
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Thanks Cecil,
Appreciate your information and comments.
I no longer have the dexterity for building but thought perhaps a reader to this post might be interested. It sure is a beautiful bird.
Jim has completed the servo installation, after using his years of building and ingenuity. Soon it will be covered but he won't fly it until spring, here in Illinois. I'll take some photos of it when he brings it for "planes for points" at one of our club meetings.
Don
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Old 06-05-2009, 06:36 AM
  #11  
oian
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Tandy Walker has a very detailed build log for the Comet Sailplane (100 pages and over 200 photos) showing every step in the construction including hatches, radio mounting, engine mounting, control surfaces etc.
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Old 06-05-2009, 06:45 AM
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Forum rules do not allow one to put a link in a post until after your third post, the previous post was my third, so here is in my fourth post and the link. www.sam15/walkersailplaneproj.html
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Old 06-05-2009, 12:10 PM
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Default New Link

Hello Oian.
The link you provided wasn't working. I found the article here;
http://www.sam15.org/walkersailplaneproj.html
And here;
http://www.sam15.org/projectindex.html
For anyone interested in a smaller version of the Sailplane, here's a 36" wingspan kit from Penn Valley;
http://www.pennvalleyhobbycenter.com...9sailplane.htm
And photos of the kit.
Ron
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Old 06-06-2009, 11:47 AM
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Ron and other Sailplane admirers,
Here's a video of Jim's beautiful "Sailplane", enjoy.
http://www.youtube.com/watch?v=h85sjKn9gyQ
What a magnificent flyer she is.
Don
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Old 06-28-2009, 01:12 AM
  #15  
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Hi to you all: I had a Goldberg Sailplane, one of the most beautiful planes I ever had:
I put an O.S. 26 four stroke on it: wish I could find another kit: I would put electric in it now. I put the servos right at the center of the fuse on the CG. Plenty of room for two HS-81's and then room for a HS 55 for the throttle. It flew wonderfully. Get it up high, cut the throttle and search for thermals. Wow! what a treat. Roger Q
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Old 07-16-2009, 03:15 AM
  #16  
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Default power options and radio gear

Hey there

beauty of a build and very intricate.

It is so hard for "modern modellers" to understand the beauty of your work as the majority are ARF addicts and have no clue where to even begin with such a project.

How are you planning to power it - or not . . what is the weight. Before you really decide on servos and the like, let us know what weight you are shooting for to ensure the proper load capability. I would hate to see a lighter torque servo stall out on you and loose that plane.

Phil
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Old 10-02-2009, 11:31 PM
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That is one great looking plane. I had a very hard time deciding between that and the Goldberg Valkyrie. I thought about it for about 6 months and the Valkyrie finally won out. I am about ready to start building the Valkyrie and maybe have it ready for the spring season. Yous is beautiful though and you have one great looking and flying plane. I'm going electric on mine, but will be adding rudder and elevator for R/C flying just like yours. Congratulations on a very nice plane.

Ed
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Old 01-07-2010, 03:36 PM
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Hi Don,

Thanks for posting the video! That is a beautiful airplane. A gentleman in our club just completed one in yellow and black.

I have a question for you: I am currently building a Goldberg Valkyrie (http://www.rcgroups.com/forums/showthread.php?t=1094906). I have the wing panels done and am working on the stab right now. My question is about rudder authority. Did Jim mention if he had any issues with rudder control? I have heard different things about the fin/rudder on the Valkyrie and some have increased its size. The Sailplane and Valkyrie are pretty similar so I'm thinking if the Sailplane was fine on that fin/rudder, then the Valkyrie will be fine as well.

Thanks,

Franny
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Old 01-07-2010, 03:42 PM
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Franny,
Thanks for your comments. I will ask Jim Kummerow who built and flew the model in the video. Is truly a superb flyer.
Don
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Old 01-07-2010, 03:53 PM
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Thanks Don. Much appreciated! The fin/rudder is next for me after the stab so I'll need to make a decision before too long. I know with my Shreshaw "Cumulus", which has a reasonably large fin and a big rudder, at slow speeds it can take significant rudder to change direction. Nothing happens very fast. My Goldberg Viking has excellent control, but my Goldberg Blazer has very poor control in the glide. I guess we'll see with the Valkyrie.

Thanks again,

f

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Old 01-07-2010, 04:33 PM
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donjiskra
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Franny,
I just phoned Jim, he said, that the rudder area on the Sailplane is 50% of the fin. When landing he had to cut the engine because it would keep on flying. So when he glided down to land, he reports happily NO problems with the rudder area or handling.
Hope this helps?
Good luck with your model.
Don
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Old 01-07-2010, 04:44 PM
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Thanks Don. I think I'm looking at about 50% as well. Mine will be electric which can really help on approaches.

I bet I'll be just fine. It really is a treat to see these big birds circling above. One day this past late summer, I had the Cumulus out and I decided to just let it go where it wanted to as long as it remained in sight. Boy, it was all over the place! Different directions sometimes turning left, others right. Sometimes spiraling tightly and then it would straighten out and just fly straight as an arrow. Really something to watch. A friend at the club posted this video: http://www.youtube.com/watch?v=TXOok_jE9FI during our annual Vintage fun-fly. We also had a large Sailplane entry that took first in the gas division. There are two more club members building the 8'+ span old-timers this winter so this year's event should be a real blast!

Thanks again. I hope to have the big "V" flying this spring.

Franny
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Old 01-07-2010, 05:31 PM
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Great video Franny, I'm not familiar with that paricular model but Jim said hhad one and it was a great flyer. The video showed it was and is.
THANKS for sharing it with me,
Don
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Old 01-07-2010, 05:46 PM
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You bet! I did a big build log here:http://www.rcgroups.com/forums/showthread.php?t=1053860

And I have some more photos here on my website: http://www.frannybrodigan.com/Cumulus.asp

It is a Ben Shereshaw design from the late 30's - a very nice flying airplane and can stay up in the lightest lift.

Franny
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Old 01-07-2010, 05:55 PM
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Hey Don? If Jim has any photos of his I'd love to see them...

Thanks, f
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