Dummy engine "Lenape Papoose"

[chris46]

The Piper J-3 Cub is typically powered by a 4-cylinder boxer engine from Continental. Unfortunately, these engines initially did not deliver the power specified by the manufacturer. For this reason, Piper announced a competition for aircraft engines with a minimum output of 50 hp. The competition was won by Lenape, which developed a small, 3-cylinder radial engine named the "Lenape Papoose." Piper then ordered 13 engines from Lenape, which were installed in a small series of Piper J-3 P aircraft.
As usual, I started building details, namely the Lenape Papoose 3-cylinder radial engine Dumy in 1:15 scale. To do this, I needed thin washers of various diameters and thicknesses to represent the cylinder cooling fins, as these could not be made in wood.

[chris46]

The two different washers were mounted on two different tubes, respectively wooden dowels, with intermediate rings. This resulted in the cylinder. The two valve supports were then mounted and fitted with half washers. To this I attached the rocker arm housings made of hardwood.
The crankcase was made from a thin-walled aluminum tube and 0.8 mm plywood attached on both sides. The front part of the housing consists of a part of a propeller spinner. After attaching the cylinders, the valve pushrods and intake lines were added. The engine dummy is now ready to be built in the model.

Chris

[TheLurker]

That looks really good.
What does it weigh?

[OZPAF]

Are those thin washers metal Chris? The motor looks great.

John

[chris46]

@ The Lurker: The dummy weighs 16 grams. Given that ballast still needs to be added to the nose of the model, the weight of the dummy wasn't a factor.
@ John: Yes, they are chrome steel washers 0.1 and 0.3 mm thick.

Chris

[Lastwoodsman]

Thur April 30 2026

Dummy engine "Lenape Papoose"

Hi chris46 !!    And that is a great looking scale laminated prop too,    to compliment that exquisite engine,  very nice.    I don't think I ever saw one on HIP before .... except mine,  .... but mine are just laminated static display props.    Looks like it will fly nicely with it.    How did you get the wood grain color?   

Lastwoodsman
Richard

[chris46]

@ Richard,

I'm afraid I have to disappoint you: I made the propeller just for display purposes. By the way, it's not the only one—as you can see from the picture, I've made a few. The diameter is only about 6 inches.
The laminated finish came about naturally by using thin-ply marine plywood, which I then varnished.

Chris

[Lastwoodsman]

Thur April 30 2026

Dummy engine "Lenape Papoose"

     Hi Chris.   Now I see.    That thin dark wood grain color, is from the glue used for the plywood layers,  and the wood color was varnished.     It works well,  and really compliments the engine.

     I should try that.   I have manually cut out and surface-painted  both sides,  of several planks for each of my propeller carving blocks,   which I then glued the faces thereof onto each other,  all together with white glue,   and clamped it all up,   and waited for it all to dry for a week.    Then I  'carved'  it.    No offense,  those were the ones I was referring to,  that I have not seen made in HPA.

    I used to have a big thread on all of the hand 'carved' props, with names, on my planes,  that is now lost to the ether from the last big HPA crash.    You just might be motivating me enough to repost it ...

     What are the names of those props and what plane did you put them on?   Your hub plates and bolt patterns and cladding look great!

Lastwoodsman
Richard

[chris46]

@ Richard, Lastwoodsman

When it comes to model building, I'm not one of those so-called "rivet counters." The overall look has to be right, without getting too bogged down in the details. That's why the propellers I make for display purposes don't correspond to a specific manufacturer or aircraft type. Of course, a wooden propeller belongs on a vintage aircraft, while a metal or plastic propeller is more suited to a classic or modern propeller-driven aircraft.

Chris

[Robert McKellar]

Beautiful work on this dummy engine and cylinders! Neat idea using washers!

Rob