My latest AADD side trip

batjac Tue Nov 01, 2022 2:16 am

Last week when I was at a club member’s garage, I noticed a Medallion .09 sitting on his bench. I asked about it and he said he got it from another club member. The engine was locked up and he didn’t know what to do. So, I took it home, cleaned it up, and test ran it on the stand. I took it over to his house this past Tuesday.

Initially he started to offer it back to me, but I told him I already had three or four .09 Medallions. He then asked if I would ever build a plane for a Medallion .09. I owned up that I probably would. He said that if I do, cut out two kits and he’d build one also. The first thing that popped into my head was an All American. As I was leaving, I asked if he had any preferences. He said something quick, and profile. So the All American is out. I figured I have all sorts of plans for an .09 that I’ve downloaded over the years from OZ, so I have plenty to choose from.

But then, my AADD (Airplane Attention Deficit Disorder) kicked in, and my mind started wandering. A few years ago I ordered a Sig Super Chipmunk wing kit to build a Sarpolus Challenger “someday”. Later I decided a .15 sized Challenger would be cool. Then I thought I’d build a Sarpolus 1/2A Challenger. So now, I figured “Why not slightly enlarge the 1/2A Challenger for the Medallion .09?” I’ve been itching to try my bladder pressure Medallion conversion on an .09, so this is perfect.

Okay, maybe not perfect, but I drew up the parts for my Cricut machine. If I did my math correctly, the wing area will be 256 square inches. The ribs, one fuselage blank, and fins are 1/16", and the rest are 3/32". There are three fuselage blanks because the largest thickness the Cricut will do is 3/32", so to get a 1/4" fuse takes two 3/32" blanks with a 1/16" blank laminated in between. I did this with a Skyray fuselage and it's stiff as a board. Doesn't bend or twist at all.

My latest AADD side trip Capture

I also drew out the parts for a FROG Talisman since I'm so wishy-washy.

The Ritalin Free Mark

**944_Jim** Tue Nov 01, 2022 3:02 am

Mark,
I watched you tease the StuntHangar crowd with this idea. I even went so far as to grab the 1/2A images from evilBay. But to go upside from the 1/2A one is genius. I'd love to try this one.

Any chance you can convert to full-size PDF for the razor-cutters among us? That's right...for the guys that still use razors...not lasers or Cricuts.

Thanks in advance for your consideration. Who knows, you may get a group build going!

Levent Suberk Tue Nov 01, 2022 5:58 am

https://www.biblejournalingministries.com/make-stickers-from-pdf-files/

Pumpkin

rsv1cox Tue Nov 01, 2022 5:28 pm

Let's hear it for AADD Smile

Remember when many of us made the Roger Harris? kit's?

Lot's of information in your link Levent.

**944_Jim** Tue Nov 01, 2022 11:28 pm

I have to wonder how this would fly with an Enya .09 in the nose...hmmm.

Levent Suberk Wed Nov 02, 2022 12:11 am

https://leapoffaithcrafting.com/cricut-wood-cutting/ Pumpkin

https://www.amazon.com/Knife-Blade-Drive-Housing-Cricut/dp/B082XSTRHC/ref=sr_1_9?crid=WMT9F7CBDSG5&keywords=cricut+knife&qid=1667365821&qu=eyJxc2MiOiI0LjQ4IiwicXNhIjoiMy42MyIsInFzcCI6IjMuMjgifQ%3D%3D&sprefix=cricut+knife%2Caps%2C322&sr=8-9 Pumpkin

**944_Jim** Thu Nov 03, 2022 7:03 pm

That's looking like a big kit for a .09. It makes my Akromaster wing look high speed/low drag, and the fuselage is pretty chunky too. Considering the Midwest kits were built for earlier .15s, although thinner wings, I have to wonder how this plane would go on a .09.

Time to go weight my oh-nines!

batjac Thu Nov 03, 2022 7:24 pm

Well, if it's too much for a Medallion .09, I can always go with a TD .09 engine. I was planning on using bladder pressure anyway.

The Versatile Mark

**944_Jim** Thu Nov 03, 2022 9:40 pm

Don't let my "public thoughts" affect your course, Mark.

I don't know or believe it'll be too much. Not after noting the little Pinto, Hunter Stunter and Gremlin are 1/2A 35"-ish planes.

I'm trying to think if paper/foam board can be used as a fuselage (with ply doublers on either side of hardwood bearers embedded in the nose). Maybe even use a truss balsa frame within foam core sheets.
More studying will happen as I consider this one. I want to build the wing first so I can wrap my head around those deep ribs! That wing has got to be really special!

I also want to see how it compares to my 34" Scientific Challenger, which is a commercialized/smaller version of Walt Musciano's 44" plane of the same name and my Veco TomTom clone kit. Both of those call for larger engines, but they have full, detailed fuselages.

I think this one will school me!

Coxfledgling Fri Nov 04, 2022 11:02 am

Since balsa is so expensive now, foam board is the up and coming go to material and used very successfully used, but mainly for electric/soarer type models.

See some examples on rcme forum. It can be "moulded" or encouraged to "curve" then adopt a "set". Used for most of structure along with reinforcement.

The chap says he has had no airframe/structural failures in the air, he does chuck them about when flying.

andrew Fri Nov 04, 2022 12:19 pm

944_Jim wrote:
I'm trying to think if paper/foam board can be used as a fuselage (with ply doublers on either side of hardwood bearers embedded in the nose). Maybe even use a truss balsa frame within foam core sheets.

Coxfledgling wrote:Since balsa is so expensive now, foam board is the up and coming go to material and used very successfully used, but mainly for electric/soarer type models.
See some examples on rcme forum. It can be "moulded" or encouraged to "curve" then adopt a "set". Used for most of structure along with reinforcement.

Foam board is inexpensive, easy to work and, with a little experience, can be formed into a number of shapes. The downside for this forum is that it is not fuel friendly and would need to be totally fuelproofed.

The wing shown has a 38" span and 8" chord; the fuselage is 26" as pictured. While I could not get a decent photo, the airfoil is very close to a Clark Y with both upper and lower curvature. Total investment for the parts shown is under $3.00. Firewall was made from a paint stick.

**944_Jim** Fri Nov 04, 2022 5:14 pm

Hi Andrew,
Thanks for posting your stats and the pictures. I know we are comparing oranges to grapefruits, but since the overall.sizes aren't too far apart, what is your target completed airframe weight? Will yours be electric or glow?

Now I'm really thinking hard about this. Even a foam/ply forward with balsa rear middle/foam sandwich may work (I'm planning beam mount).
Huh...

andrew Fri Nov 04, 2022 8:06 pm

944_Jim wrote:
............what is your target completed airframe weight? Will yours be electric or glow?

Gosh, Jim, I really haven't thought about it. I tossed everything you see in the pictures plus the vertical fin and rudder on the scale and it came in at 11 ¼ oz. For structure, it only needs upper and lower fuselage sheeting to finish up -- I don't plan to have landing gear on this. I may add some accent stripes, but don't intend to paint it.

It will be electric -- the motor is a 2212/13T rated at 1000 KV running on, probably, a 1300 mAh Lipo. I will be using two (R/E) 17 gram metal geared servos and a 20A ESC. With 304 sq. in. area, I should have some wiggle room.

A 20" x 30" sheet of Ross foam board weighs around 7 ¼ oz -- I think I paid about a buck a sheet, IIRC.

With paper on both sides, it's pretty stiff; peel one side, and you can bend toward the foam side; peel both, and it becomes too bendy (sp?) for my usage.

batjac Sat Nov 05, 2022 2:10 am

I sent Jim a copy of what I've drawn, since he was interested. He suggested that I might make what I have available to anyone else here who's interested.

I'm not sure I'm happy with the wing as drawn. When Dick Sarpolus drew his 1/2A Challenger, he only sheeted the center section. He did not sheet the leading edge or the trailing edge, so that's how I drew it. But I'm not sure I like it. It'll be lighter, but I'm not sure how much torsional strength it's gonna have. I am currently cutting out the wing ribs, and I'll build the wing in the next couple of days. but if I'm not happy with it, I'll redraw it with leading edge and trailing edge sheeting, added weight be darned.

If there's interest after I've got it finalized, I'll send the .pdf file to anyone who wants it.

The Apprehensive Mark

getback Sat Nov 05, 2022 6:17 am

Hey Mark , where did you get the plan from ? I can't see the plan you show very well and the only one I can find is OZ 52" W/S and it has the reinforced LE >>

batjac Sat Nov 05, 2022 2:21 pm

Here's the .jpg file I have for the 1/2A Challenger. I don't remember where I found it, but it was a while ago.

My latest AADD side trip 1-2-A-Challenger

The Forgetful Mark

getback Sat Nov 05, 2022 3:42 pm

thanks Mark that is a lot clearer , yes needs LE support . IMOP

**944_Jim** Sat Nov 05, 2022 4:32 pm

Go to eBay:
https://www.ebay.com/itm/185472236061

batjac Sat Nov 05, 2022 5:40 pm

944_Jim wrote:Go to eBay:
https://www.ebay.com/itm/185472236061

No, I can't use that one. It has a flat bottom airfoil.

The Well Rounded Mark

duaneh Sat Nov 05, 2022 5:55 pm

Following with interest. A worthy project, Mark. Add me to the list of those wanting a pdf file of the finished plan.

And even though you didn't ask, I personally would not D-tube the wing. Once covered, it will be plenty stiff enough. Notice that neither the Flite Streak nor Ringmaster have LE sheeting, even in their .35 size incarnations.

**944_Jim** Sat Nov 05, 2022 7:34 pm

batjac wrote:
No, I can't use that one. It has a flat bottom airfoil.
The Well Rounded Mark

Mark,

He's got it labelled incorrectly. Look at his picture. It IS the same as you first shared, and is the one I started.looking at. I grabbed my copy straight from eBay because the first shared file was so small. His blows up loaded into Adobe Acrobat and scales up to full size with little loss in detail. There are ways to scale up and re-save as if the file were destined for larger paper sizes. While some files get really pixilated, others can take the "magnifying operation" with little loss of precision...specifically if the original image is high dpi to start with. I really need to figure out how to trace PDFs to generate a rastor file, at which point the new copy looks more like your custom jpg.

I just like your larger plan. Since I would be hand cutting, I would cut my LE for the next square section balsa up (strength), and lap the LE skin against the proud edge but cut into the relevent ribs...if I go balsa. Or I'll run several smaller stringers across the curves while keeping the spar.

I have access to paper-covered foam core in (I believe) 5/32". Seeing the curve on the above foamie wing, I'm leaning in that direction. This is for mocking up a knock-about, "who cares" plane, so fuel proofing would be paper and Elmer's white glue covered with Rustoleum or spray polyurethane.[/quote]

But then, I'm looking for an excuse to play with foam/paper. Yeah, I'll get schooled!

Oh, and I dropped my SIG Akro .15 fuselage on your R1...it appears the Akro shares an awful lot with the original Challenger, from which the eBay guy scaled down to the 26-ish" plan. Given the Akro was designed for earlier .15s (like the Fox), I'm beginning to believe a decent Cox .09 may have the stuff to pulls yours!
See how much of your rib is visible inside the Akro wing cut-outs:

andrew Sat Nov 05, 2022 7:43 pm

batjac wrote:
944_Jim wrote:Go to eBay:
https://www.ebay.com/itm/185472236061

No, I can't use that one. It has a flat bottom airfoil.

The Well Rounded Mark

Mark -
I believe the one that Jim referenced is actually the original .jpg file that you posted. Although the title states flat-bottomed, the plan shows a thick symmetrical airfoil. I have that plan, 21" span, with Sarpolus as the designer, saved as a .pdf if anyone is interested. To print, you would need to choose scaling percentage that meets your needs.
a--

EDIT: I had not seen Jim's post when I posted. In any event, I do have a relatively clean .pdf for anyone.

batjac Sat Nov 05, 2022 11:34 pm

Jim, that is interesting that they are so close. If I can build this one as light as I plan, the .09 should do well.

The Dieting Mark

**944_Jim** Sun Nov 06, 2022 12:19 am

batjac wrote:
The Dieting Mark

Jeez, you crack me up! lol!

Ken Cook Sun Nov 06, 2022 6:51 am

I have a Challenger kit. It's probably been 30 years since I purchased it and it was expensive back then. In addition, the wood selection which was all top quality Sig balsa is impeccable. I just dug out the kit and to my surprise the cost was $45. I've always wanted to build this kit and other kits always seem to take precedence. This was the pre Norvel era. Bill Noyes kitted this version. Bill Noyes was legendary in all aspects of the hobby, carrier, stunt,scale, speed etc. Just a couple of things I've read in this post. Weight is extremely critical in regards to planes of this size. I see mention of the Akromaster. The Akromaster is a neat flying plane. However, it's a real porker. Too much emphasis in building it like a battleship. Sig control line kits in my opinion are not notoriously known for light wood. I will say Midwest wins hand down in supplying baseball bat stock.

I see mention of sheeting the leading edge, while that is a requirement of the larger version, absolutely not needed on a 1/2A. My version utilizes a 1/2 x 3/8" leading edge. No gear blocks or ply ribs for wing mounted gear. The gear is mounted to the leading edge and is sandwiched with plywood to the back of the leading edge. This makes for a big weight savings. The doublers in my kit are also 1/32". I use 1/16" ply on .35 size stunters so I see no reason to use it on a 1/2A. There's no spars at all and a wing this size with the appropriate sized leading edge wouldn't require spars.

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