Pietenpol Air Camper (oz6161)

About this Plan

Pietenpol Air Camper. Scale model homebuilt. Wingspan 84-1/2in, area 1267 sq in, for .61 power and 4 channel RC. Model # pl-869. Designed by Gene Wallock. Featured in RCM 7-82.

Quote: "In 1932, the Flying and Glider Manual presented the construction article on the full size homebuilt of the Air-Camper. It was powered by a Ford Model 'A' engine. This 1/4 Scale replica is a winner with an U.S. .60 four-stroke.

I have admired the Pietenpol Air-Camper for years because of its exquisite simplicity and subtle charm. Several years ago I had the opportunity to copy the original 'Flying and Glider Manuals' published by Fawcett Publications in the late twenties and early thirties. The 1932 edition had the construction article for the full size aircraft, including the Model A engine conversion. A few years ago I joined the Experimental Aircraft Association (EAA) and to my pleasant surprise, they offered reprints of the original manuals. I ordered the set, saw the Pietenpol article again and decided I had to model it.

The O.S. .60 4-cycle engine came on the market and Quarter Scale modeling was in full bloom. A quick check of dimensions resulted in an 84-1/2 in wingspan model. The manual text revealed the Clark Y airfoil was tried on early versions and the Clark Y is an old standby in modeling, so the model designed started to click. Tail area is especially vulnerable to scale modeler's 'let's make it bigger' attacks. I figured that at Quarter Scale no enlargement was necessary. (I feel the same way about Peanut Scale.) Let's face it, an airplane is completely scaled down or it isn't scale. It's Stand-Off, butcher or fish, but scale it ain't.

The construction style was the next consideration. I liken solid sheet construction building apple crates and foam is something that makes shaving easier and girls more proportional. After five minutes consideration, I decided to draw it using scale construction. Fortunately, wood sizes in the 1930's were nice and comfortable, like 1 in square or the ever popular 1 in by 3/4 in. Dividing numbers like this by four may be done in your head, unless you've been educated with new math. In that case, buy a calculator and get familiar with the number 4 and the divide button.

After the plans were drawn, I took a few modeling liberties:

(1) Solid ribs were used instead of built-up. I did this because someone else may want to built it and they might not share my passion for building.
(2) The scale landing gear requires an expert tin bender for the fittings and that technique I leave to the master - Lou Proctor.
(3) My '71 Chevy Kingswood wagon would transport the model assembled very nicely; but my good friend, John Camp's Porsche 924 wouldn't. John wanted to build one with me, so his car became the transport envelope. Thus, the three piece wing came to be.
(4) Cabanes that aren't readily removable create building problems because they usually end up in your eye, nostril, or some other part of your anatomy while you're putting a sanding move on the model. A broken cabane in a finished model will cause grown men to weep at the repair prospects. Relax, they're removable.
(5) A steerable tail wheel was used in lieu of a re-bent Model T 4th leaf spring. It makes ground handling easier and was used on some full size Pete's.
(6) Wire rigging was eliminated as a structural requirement. Obviously, it can be added for maximum scale points.

Scale Reference. The 'EAA 1932 Flying and Glider Manual' is my primary source. However, in 1981, there were 54 Air-Campers registered in flying condition, so a little sleuthing and you'll probably find a full size example at a local flying field (would you believe somewhere in your state?). I have old magazines that show them with cub type wheels, motorcycle wheels, Lycoming engines, radiators mounted in the cowl chin and Mr. Pietenpol's latest example had a Corvair engine in it. If you want to build it for sport flying, build and finish it to your own idea of what your full size one would look like. Remember, it is a homebuilt.

Construction Considerations: Before starting construction, the following must be established:

(1) Engine: The O.S. .60 4-cycle is ideal for scale sound. The K & B .61 provides a bit more power on the same prop and fuel (a 16/6 Y & 0 and K & B 100 fuel). You say a 16/6 won't work on a K & B .61 — wrong! Run the engine slightly rich to prevent overheating and enjoy. Actually, any cross scavanged (Non-Schnuerle) .60 will be fine or a 4-cycle up to .90 c.i. I do have a Quadra in my Sears chain saw and it cuts wood, not air. The model is not designed or stressed for the industrial type engine. The model should weigh a little over ten pounds ready to fly. That's the whole airplane, not just the engine. With the 20 ounce 0.5..60 4-cycle, the model will balance with minimum nose weight.

(2) Gas Tank: The original model uses an 8 oz. Kraft Slimline tank which is good for 15-20 minute flights. The tank's physical size is needed to establish the dimensions of the tank doghouse. Most models have internal tanks with plumbing running through firewalls. Neat, till they leak or the line deteriorates. The Pete has an oil wall with an opening (door of the doghouse). The tank slides in through the oil wall and is held in place by foam tape on the sides and rear (vibration isolation) and the engine mounting plate in the front. If the tank fails, remove the engine plate, pull the old tank out, shove a new one in and hook up lines directly to the engine. The doghouse uses a light ply floor and back, and 1/64 in ply cover. Naturally, the inside has several coats of K & B resin.

(3) Aileron Servo: The aileron servo output (wheel or arms) driver will determine the location of the aileron bellcrank control rod holes in the ribs. The original model used a Kraft KP-15 III servo and Sullivan Gold'N-Rods. Contrary to popular opinion, temperature stability was no problem with the rods.

Construction. The Pete is built in the following sequence to insure proper alignment and minimum wood waste:

(1) Fuselage sides, cabanes and 1/8 ply wing center ribs.
(2) Fuselage frame and landing gear.
(3) Wing and struts.
(4) Tail group.
(5) Fuselage completion.
(6) Assembly and covering.

Fuselage Sides, Cabanes & Center Ribs: I assume any modeler building the Pete doesn't need 'glue stick A to stick B instructions,' so I'll describe my building technique. I build both sides at the same time to insure identical sides. I use the outside outlines and the front edge of uprights and diagonals as reference to eliminate wood size tolerance..."

Supplementary file notes

Article pages, text and pics, thanks to JohnSH. Very long and detailed, at 16 pages.

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