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Feb 23, 2020, 08:49 PM
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Question

Can anyone help identify this Balsa Glider?


I just received this Glider (blue and yellow 3 piece wing) as a gift and I would like to to identify it. I have never had a balsa unpowered glider, it does not have hi-start hook and it has a lot of lead weight in the nose. I have a lot of questions...
Any information (Model type, CG?, recommended battery?, best options like installing a motor pod or a hi-start hook?, can I use smaller servos?) will be greatly appreciated.
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Feb 23, 2020, 09:35 PM
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prodjx's Avatar
It's an Airtronic's Olympic 650. Battery can be a 4 pack AA. C of G would be at the spar. Initially the hook would be somewhere between the leading edge and the C of G. That's an aweful lot of nose weight.
Feb 23, 2020, 09:57 PM
Brett
bjaffee's Avatar
Quote:
Originally Posted by prodjx
It's an Airtronic's Olympic 650. Battery can be a 4 pack AA. C of G would be at the spar. Initially the hook would be somewhere between the leading edge and the C of G. That's an aweful lot of nose weight.
I wonder if the original owner was using a small battery or something.
Feb 23, 2020, 09:59 PM
Brett
bjaffee's Avatar
A few years ago I re-built an Oly 650 that was in pretty bad shape. The build log (or just the pictures) might be of interest if you want to see what some of the internal parts of the plane look like https://www.rcgroups.com/forums/show...Gentle-Lady%29
Feb 23, 2020, 10:16 PM
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GliderJim's Avatar
Oly 650 was my first sailplane, and the only one I ever did an hour flight with as well. Still have it. It's in need of a re-build, which I thought I was going to get to this winter but didn't.
Feb 23, 2020, 10:28 PM
Registered User
Plans and instructions are on Outerzone.

My first RC sailplane was an Olympic 650. It was probably a good trainer, though I wasn't qualified to judge at the time. If the servos are in fine shape, you could just use them. If not, you can go smaller. Do they still make HS-81's? If you have a large and a small servo, put the large one on the rudder. Not because it takes more power, but because it will probably get banged around more.
Feb 24, 2020, 04:10 AM
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Thread OP

Thank you all for the quick (and helpful) responses


I will start reading up on it and see if I can do without all that weight!
Feb 24, 2020, 06:22 AM
Gots me a good used Hobie Hawk
Steve Corbin's Avatar
It's fun trying to reduce nose weight. I was surprized to find out how much lead it takes to counterbalance the triangle stock and epoxy I used to make one of my first repairs, which was simply putting a fin back in place.

I've found that balsa pushrods can be very light and still do their job, it's a matter of arranging things so that the compression loads are as close to being straight down the center of the rod as you can get it.

Heavy balsa sticks can be split open and hollowed out some. They can also be tapered at the ends.

I have reduced tail weight and also eliminated nose weight by simply sawing off the nose section and splicing in a section of EPP foam, which can absorb loads imposed by my oh too typical "landings".
Just getting the nose block furthur fwd an inch or two can make a big difference, keeping in mind the "flywheel effect" on handling qualities.

If you already have a light glider, leave the heavy one alone and use it when it's "blowin' like stink", that's how I dealt with the situation when I was given an " Early Bird"---a short nosed design that due to the builder's desire for a strong tail it had almost as much weight-in-the-nose as the glider weighed empty---but when it got really windy it was often the only show on the hill.
Last edited by Steve Corbin; Feb 24, 2020 at 06:29 AM.
Feb 24, 2020, 09:22 AM
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prodjx's Avatar
If you can find Al Doig's Sailplane and Soaring manual it has all the instruction's and photo's you could possibly need to build an Olympic 650.
Feb 24, 2020, 03:16 PM
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I'd be surprised if it was too heavy, as is, to fly fairly well. Don't change things unless you know there's a problem.
Feb 24, 2020, 07:34 PM
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Quote:
Originally Posted by lincoln
I'd be surprised if it was too heavy, as is, to fly fairly well. Don't change things unless you know there's a problem.
Thank you, that is good advice.
Feb 24, 2020, 07:49 PM
Brett
bjaffee's Avatar
Quote:
Originally Posted by prodjx
If you can find Al Doig's Sailplane and Soaring manual it has all the instruction's and photo's you could possibly need to build an Olympic 650.
It's available here: https://rclibrary.co.uk/title_details.asp?ID=1062

Here are the plans: https://outerzone.co.uk/plan_details.asp?ID=6040
Feb 24, 2020, 08:37 PM
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Thread OP
I did notice, however, that the horizontal stabilizer is not parallel to the wing when looking from the front or the rear. If for example, I look from the rear, the right side of the horizontal stab. is higher than the left side in relation to the wing. I do not know how (or if at all) this could affect flight.
I guess I could rise the fuselage wall on the right side with some kind of wedge to bring the wing to parallel with the horizontal stab.? But it is about 1/4" difference so the angle is very noticeable...The tail has some covering patches suggesting it was broken at some point.
Feb 24, 2020, 08:39 PM
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Thread OP
Quote:
Originally Posted by bjaffee
Thank you, downloading the manual!
Feb 24, 2020, 09:45 PM
Brett
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Quote:
Originally Posted by HARD DRYVE
I did notice, however, that the horizontal stabilizer is not parallel to the wing when looking from the front or the rear. If for example, I look from the rear, the right side of the horizontal stab. is higher than the left side in relation to the wing. I do not know how (or if at all) this could affect flight.
I guess I could rise the fuselage wall on the right side with some kind of wedge to bring the wing to parallel with the horizontal stab.? But it is about 1/4" difference so the angle is very noticeable...The tail has some covering patches suggesting it was broken at some point.
Can you take a picture of it? If you are saying that it, would require a 1/4" shim to get the wing parallel to the stab, that's quite a bit. It'll still fly, but it will probably require a good amount of rudder trim. At any rate, you can still shim up one side of the wing to level it out, with balsa, or just layers of tape, if it doesn't need too much.


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