SSSC-2 Higher AR and less drag for better soaring ( mini-powered sailplane)

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Pops

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Any one want to voice there ideas for a little better soaring airplane. We will call it the SSSC-2 . Light weight, more wing area and less drag.

SSSC but extending the wing from 30' to 34'and extending the wing cord from 48" to 54" for a wing area of 153 sq' . Same 24" wide fuselage. Hopefully same weight of the SSSC of 485 lbs. 1835 cc, 60 HP, non-electric VW engine.DSCF0013.JPG
 

Marc W

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You must have some trick up your sleeve to expect the same weight with more wing area!

I would go with a higher aspect ratio, carbon spar and ditch the strut. If you can do that, sign me up.
 

Victor Bravo

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If you can live with just a little better soaring, then adding wingspan alone might do what you want. But building another whole airplane to get just the ability to climb in a strong thermal... seems like you're passing up a bigger opportunity. Not suggesting you try to build a cross country glider of course, but if you can make something that has maybe the performance of the old Schweizer 2-22 and self-launch, then you can have a lot more fun.

What you might think about is whether you can easily create a retractable main wheel under the center,a nd have it work with the SSSC structure. If you can retract a single main gear (even if it goes forward under the engine), then it will be worth doing all the other little clean-up stuff, extending the span, using a little better airfoil, etc. etc.

Getting rid of half of the landing gear and tire weight would go a long way toward keeping the weight the same but with a longer wing.
 

Pops

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I was thinking that way. Maybe having one wheel under the CG like my old I-26. For the weight, I know I can save some weight over the SSSC of 485 lbs. At first the SSSC weighed 450 lbs. Then I added a battery for the radio, electric elevator trim servo, went from small 5" tires and wheels to large tires and 6" wheels.
It all adds up. I watched every ounce on the firewall forward, but not so much on the airframe. I know I can do better.

I would like to go to a CF wing, but I have to face it, designing a CF wing is over my head.
 

103

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Any one want to voice there ideas for a little better soaring airplane. We will call it the SSSC-2 . Light weight, more wing area and less drag.

SSSC but extending the wing from 30' to 34'and extending the wing cord from 48" to 54" for a wing area of 153 sq' . Same 24" wide fuselage. Hopefully same weight of the SSSC of 485 lbs. 1835 cc, 60 HP, non-electric VW engine.View attachment 99087
Dan you know I like the SSSC! Combine it with gliding/Soaring my favorite form of flight! That said air restart would eat into the low weight objective. Please keep fleshing out the concept!
 

Victor Bravo

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II would like to go to a CF wing, but I have to face it, designing a CF wing is over my head.
I think a mostly or all carbon wing is a waste of time for what you are specifically trying to do. You'd be spending a lot of time leaarning how to make the wing, design the wing, and learning how to use the materials. And then after all that you are still making a very low performance glider.

Adding the CF strips to the existing wooden spar, now that is probably a very worthwhile thing on the Single Seat Soaring Cub (no charge for the clever name). A lot of bending load strength for only a little bit of extra work and material cost. I'll bet a hundred bucks or so worth of the Graphlite rods or bars would be more than enough to offset the increased span.

Jim Marske and several of the people on the HBA forum will be able to help figure out the math and number of layers of carbon on the wood and all that.

Maybe look into finding a retractable nosegear assembly and mounting trunion, from some very lightweight airplane, and see if you can figure out how to cobble that onto the fuselage structure. That would probably put you a long long way ahead compared to fabricating something on the bench. In order to kee the engine mounted in the same place and have prop clearance, it's going to be a fairly tall main gear, which will need a little more room to retract. Forward into the cowling, or rearward behind the seat, whichever works best. And you can use a 4.00 x 4 Lamb tire or 5.00 x 5. No need for aa big Cub style wheel for what you want to do.

ALSO, consider that if you are extending the wingspan by 20%, at least half of that increase should be a swept, tapered wingtip. Straight trailing edge, single or double swept leading edge with a little kick up in dihedral at the very end. This is proven in many gliders and it works. You can carve this out of foam, or build it all up out of wood, whatever you want. But this "Scheumann Planform" will make a measurable difference in low speed turning and climbing and thermaling.

Don't take the aileron all the way out to the wingtip, make the last foot of the span fixed with no moving aileron surface. We learned this in the high performance ships, when you are thermaling and the wingtips are working hard, the aileron flapping up and down (maneuvering in the thermal) will cause a tip stall or a drag spike you don't need. (Yes of course this was a bigger concern with the racing stuff, but the concept is still valid... remember you'll be spending a lot more time climbing than running with this airplane).

You will also need to significantly increase the differential throw some amount over and above whatever the Koala or SSSC needs. Double the up versus down aileron travel is not out of the question. Design your bellcranks and horns with different holes and ratios, so you can play around with this by moving the clevis, just like an R/C model. This is new territory and chances are you can't figure out the final configuration on paper ahead of time. Even if you could, it would take longer than building the airplane.
 
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plncraze

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Marske Aircraft's website has a composite design book for sale. It is not a complete guide but will get you started. Marske is a sharp guy and has been using some type of plastic since his XM-1.
 

Pops

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I think a mostly or all carbon wing is a waste of time for what you are specifically trying to do. You'd be spending a lot of time leaarning how to make the wing, design the wing, and learning how to use the materials. And then after all that you are still making a very low performance glider.

Adding the CF strips to the existing wooden spar, now that is probably a very worthwhile thing on the Single Seat Soaring Cub (no charge for the clever name). A lot of bending load strength for only a little bit of extra work and material cost. I'll bet a hundred bucks or so worth of the Graphlite rods or bars would be more than enough to offset the increased span.

Jim Marske and several of the people on the HBA forum will be able to help figure out the math and number of layers of carbon on the wood and all that.

Maybe look into finding a retractable nosegear assembly and mounting trunion, from some very lightweight airplane, and see if you can figure out how to cobble that onto the fuselage structure. That would probably put you a long long way ahead compared to fabricating something on the bench. In order to kee the engine mounted in the same place and have prop clearance, it's going to be a fairly tall main gear, which will need a little more room to retract. Forward into the cowling, or rearward behind the seat, whichever works best. And you can use a 4.00 x 4 Lamb tire or 5.00 x 5. No need for aa big Cub style wheel for what you want to do.

ALSO, consider that if you are extending the wingspan by 20%, at least half of that increase should be a swept, tapered wingtip. Straight trailing edge, single or double swept leading edge with a little kick up in dihedral at the very end. This is proven in many gliders and it works. You can carve this out of foam, or build it all up out of wood, whatever you want. But this "Scheumann Planform" will make a measurable difference in low speed turning and climbing and thermaling.

Don't take the aileron all the way out to the wingtip, make the last foot of the span fixed with no moving aileron surface. We learned this in the high performance ships, when you are thermaling and the wingtips are working hard, the aileron flapping up and down (maneuvering in the thermal) will cause a tip stall or a drag spike you don't need. (Yes of course this was a bigger concern with the racing stuff, but the concept is still valid... remember you'll be spending a lot more time climbing than running with this airplane).

You will also need to significantly increase the differential throw some amount over and above whatever the Koala or SSSC needs. Double the up versus down aileron travel is not out of the question. Design your bellcranks and horns with different holes and ratios, so you can play around with this by moving the clevis, just like an R/C model. This is new territory and chances are you can't figure out the final configuration on paper ahead of time. Even if you could, it would take longer than building the airplane.
No problem in designing the single wheel retractable gear. I also understand the wing platform needed for a sailplane. Also the need for the more differential throw in the ailerons because of the longer wing. In the SSSC I got the differential right on. I can design in wood and aluminum but for an ALL CF wing I would need to learn or get help.

I would rather not have a retractable wheel because of the added weight of the hardware. But the negative part of the fixed wheel is the need for the ground clearance for the prop. Means putting the engine thrust line above the WL and the resulting trim change with power change. Easy to get the prop ground clearance with a retract gear. All a large trade-off.
I like the name.
Just thinking of designing for a low performance powered sailplane. I worked lift in the SSSC very often. Have gained about 8K at one time. Fun to work weak lift and see how good you can do. One time with the surface winds of over 30 knots, I ridge soared a Cessna 172 from Selinsgrove, Pa to near Morgantown WV. down the mountain ridges. Just used power to jump over the valleys from one ridge to another to keep somewhat in the direction I wanted to go. Fun day.

On the SSSC, Not one part is the same as the Fisher Koala 202 or the Super Koala, it just looks close to the 202 for the Cub look. I couldn't think of a name I wanted to call it at the time and ask the owner of Fisher if it would be OK if I called it a Koala 202 on the paper work since it looks sort of like one. He said OK. Latter he said he was thinking of doing the same thing and coming out with a kit version as soon as he finished building one of his kits. but sold the company before he did.
 

TFF

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I think I would design the wing as original shape, but I would have 5 ft plug in tips. Pop them out for regular airplane and storage. It would also give a more sailplane wing. I think I would pylon mount the wing with a low deck behind the wing. Wheel pants and covers for a spring type gear for drag.
 

Pops

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I think I would design the wing as original shape, but I would have 5 ft plug in tips. Pop them out for regular airplane and storage. It would also give a more sailplane wing. I think I would pylon mount the wing with a low deck behind the wing. Wheel pants and covers for a spring type gear for drag.
Lot to good ideas to think about.
 

Pops

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Dan you know I like the SSSC! Combine it with gliding/Soaring my favorite form of flight! That said air restart would eat into the low weight objective. Please keep fleshing out the concept!
Neighbor had the pull start on his Chief with the A-65 engine. Worked good and was light weight. He had an extra and I got to do a good inspection of it.
If someone wanted a side job of manufacturing one designed for a VW engine. With more and more VW's used for airplanes I believe there would be a market.
 

Lendo

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I would suggest buy Jim Marske's book, calculate the cap loads and go from there. I would also suggest the Carbon Rods have to be held in place to what ever type of WEB you choose to use and this would require a number of +/- 45° Spar wraps. I have seem where the Rods are embedded into timber Spar with Flox, I wouldn't recommend that for a number of reasons. However if you buy Jim's Manual, he's always happy to help with designs.
George
 

Pops

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The video doesn't show the pull handle the is at your left knee on the left side. The handle hinges on the floor if I remember correctly. Cable attaches below the handle grip.
 

John.Roo

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Any one want to voice there ideas for a little better soaring airplane. We will call it the SSSC-2 . Light weight, more wing area and less drag.

SSSC but extending the wing from 30' to 34'and extending the wing cord from 48" to 54" for a wing area of 153 sq' . Same 24" wide fuselage. Hopefully same weight of the SSSC of 485 lbs. 1835 cc, 60 HP, non-electric VW engine.View attachment 99087
Hello!
Because this thread is a "little bit" about soaring I will react :) In thermals is a very important to see who is arround. Every glider pilot carefully watch upper hemisphere. In a high wing airplane config. you are "closing" view during turning with your wing. Even window on the top (between wings) doesn´t help enough. So please be very carefull using same thermal if they are other gliders arround. In hangglider area will be situation better - you will probably need bigger turn diameter than hangglider pilots + they also look down. But still... soaring is "group sport" when the gliders are often really close to each other so perfect vissibility is important.
Good luck with your modifications and enjoy simbiosis with forces of nature :)
Martin
 

BBerson

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I like low wing. Of course, low wing suggests a strong urge to go cantilever also. The removal of the strut drag can cancel some of increased induced drag effects of less span. So the result is a more compact sport glider.
The single wheel is suited to low wing. (think RF-3)
 

WonderousMountain

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Hi,

I know very little about your tranport. However,
the plyon mount seems like it could do a lot for
Your thermal rise in the 10.5 Meter suggested.

THX,
LuPi
 
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