Piper Skycycle - RC Groups
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Jan 26, 2003, 01:53 AM
Registered User

Piper Skycycle

My latest RFFS 100 project is the PA-8 Piper Skycycle. Owning one of these little rascals was one of my fantasies as a school boy. The original was designed to use a Corsair drop tank for the main fuselage so there are no flat panels or square edges to design or build from. I transferred a set of factory-derived plans into AutoCad and lofted the parts and assembly fixtures from that. In order to duplicate the drop tank shape I went back to an old balsa sheet forming technique where I used a soaked Ace elastic knee bandage to wrap and hold the sheet against a carved form until it dries. This is an excellent way to form compound shape in a balsa sheet if you are willing to spend the time to carve a forming block. The wing panels are pre-curved using the same technique. The aft fuselage cone wrapped and shaped on a tapered form like we did on rubber powered models. All of the balsa in the model is 1/32 sheet except for 1/16 ribs and the carved balsa cowl and tail cone. Fuselage bulkheads are two-ply 1/32 balsa. I wound oval-shaped actuators with special magnet armatures to provide a little more control authority. I will try 6:1 on the M20 LV initially but changing out to other ratios takes only a few minutes. The bottom of the front cowl is held on with magnets for motor and battery removal. There is room for two Lipoly 170's but I intend to use just one. The plastic canopy is heated and pulled over a carved form and is also retained with magnets. I couldn't resist some"scale" features: a dummy engine, a fuel gauage (which is also a shorting bar switch for the battery lead), gear spats, headache bar and steerable tail wheel. These added about 4 grams.
The weight as pictured, ready for paint, is 27 grams. With a 170 lipoly and some color it should be right at 33 grams. The wingspan is 16".
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Jan 26, 2003, 05:26 AM
Thats NOT indestructible
j8m8l's Avatar

That is the most beautiful micro plane, that i have ever seen !!

You have quite some gift

Jan 26, 2003, 08:16 AM
Registered User
buzzsaw 46's Avatar
I have to second Josh, that is an incredible bit of modeling. Looking forward to flight reports
Jan 26, 2003, 09:57 AM
Team 30 Micro EDF
Mike Taylor's Avatar
I concur; nice job. Very nice modeling going on there. I, too, would be interested in flight reports.

How many pieces did it take to mold the fuselage? I like the Albatross fighters with their oval fuselages, and this would be a great way to form those... I remember building larger C/L models (studi-bilt?) that came with heat-formed, 2-piece balsa sheet fuselages.
Jan 26, 2003, 10:18 AM
Registered User
bmutlugil's Avatar
Hi Carl,

This is a wonderful model - even if not finished yet.. Keep posting the developments.. Can you give more detailed information on the actuators?

Best regards,

Jan 26, 2003, 12:13 PM
Living Room Aviator
drliu's Avatar
Wow-- you and Chris3D should get together and design the new World Trade Center

Beautiful work!

Jan 26, 2003, 02:25 PM
in persuit of low wing loading
Gordon Johnson's Avatar
It looks great. Can't wait to see it painted.

Jan 27, 2003, 12:22 PM
High Exalted Poohbah
planeman's Avatar
Astounding work, Carl!

I have a hunch that, like me, you were a scale rubber model builder for a long time and are now having fun with the new R/C stuff and the capabilities you always wanted for the small models you like to build. Fun, isn't it!

Jan 27, 2003, 09:52 PM
De-Brushed user

Coolest little plane

I cant wait to hear how it flies. I hope there will be some plans in the works, even though i dont think i could build it with my limited skills. Ive wanted a skycycle ever sence i saw a picture in a magazine. It has got to be one of the coolest looking litle airplanes around. Good luck with the flight.
Jan 27, 2003, 09:59 PM
Foam rules
Thatovalguy's Avatar
That thing belongs on a shelve for a long while just to admire that workmanship. Than on a long dull day you break it out a fly it. Actually I'd leave it on the shelve. I'd be affraid of hurting it. But thats me, you go have fun with it and let us know how it does.
Jan 30, 2003, 02:19 AM
Registered User

PA-8 Skycycle

Several asked to see the finished model pics so here are a few views. The gravity Gods don't cut much slack when it comes to painting a micro model. Fortunately the original had a simple color scheme. I used my finish-of-choice for the last 50+ years--AeroGloss, masked and sprayed lightly. It added 3.5 grams to the model....oh well.
There were a couple of questions asked:

Mike, I pulled some two-piece fuselage parts but didn't care for the "bunching" at the small diameter. I ended up forming four approximate one-third sections and trimmed them to one fourth so it was made of four pieces. Thirty years ago I formed an Albatross fuse out of 3/32" balsa in two pieces. I think it is best to shoot for four pieces and fixture up so the match lines can be accurately laid out and cut. I took some pics of the process that I can provide if you are interested.

Bulent, The actuators are elongated coils, #39 wire, 500 turns, 60 ohm, sort of oval to clear 1/8" diameter by 3/8" magnet armature. Armature support and bearing arrangement is the bead-and-brass head pin technique I posted earlier. The dual actuator assembly, mount and wires weigh 2.4 grams and the force is 2.8 gm-cm. Centering on the companion magnets is probably adequate but I may add a rubber "hinge" anyway. The hinges are pieces of #32 wire insulation for sleeves and .010" M.W. pins. Push rods are .025" CF with .015" wire end fittings.
Jan 30, 2003, 07:46 AM
in persuit of low wing loading
Gordon Johnson's Avatar
You've been busy. I can't wait to hear how it flys. It looks terrific painted.

Jan 30, 2003, 08:49 AM
Registered User
Dave Wulff's Avatar

Very nice, as usual. If you haven't already, check out Dave Robelens paint method. It is described again in the Feb issue of RCMF in the article about his Bristol Brownie. He uses auto touch-up paint from a spray can, sprays it into a jar, then thins it an additional 50% and airbrushes it. His BB is 14" span as compared to your 16" Piper, but has alot of fuse area, so I would guess the surface area is at least equal. His finish looks pretty good and only added 400 mg in weight. Your actuator specs look good too.

Dave Wulff
Jan 30, 2003, 09:04 AM
Team 30 Micro EDF
Mike Taylor's Avatar

Yes, I'd like to see pictures of what you have done. I have had experience making molds and forming FG fuses and other parts, and molded plenty of weird wooden shapes (for musical instruments as well as models), but I would like to learn more. That is what is so cool about this group of people - willing to share ideas and techniques, and willing to learn from others at the same time.
Jan 30, 2003, 11:34 AM
Registered User
hobbyshopguy's Avatar
Carl please take this as the most substantial compliment I can think of--- looking at your amazing model made me think of a scale model builder in San Diego: Bill Noonan. For a while he would get published, his rubber powered plane plans --- at the time I thought I would never see more perfectly executed miniatures that FLEW.

I am corrected. You and Noonan are in a tie. What an extraordinary package you have produced.......

Paul in Athens GA

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