Piaggio Pegna PC.7 racer

[apophenia]

http://aeroweb.lucia.it/en/history/pegna1.htm
http://aeroweb.lucia.it/en/history/pegna2.htm
http://pagesperso-orange.fr/alain.vassel/piaggio.htm

[jcf]

Here is Seattle area modeler Jim Schubert's build of the Noix 1/48th kit.

Jim scratchbuilt the trestles.

Jon

[PR19_Kit]

Hmmm, I can see one of those bursting to get out of an MC-72 model somehow.

Delta's MC-72 needs so much work to make it into an MC-72 you might as well go the whole hog and make PC.7 out of it. Now where did I put that much delayed MC-72.....?

[GTX]

This just begs to be updated into a WWII seaborne fighter operating in the Med'!!!

Regards,

Greg

[jcf]

This just begs to be updated into a WWII seaborne fighter operating in the Med'!!!

Regards,

Greg

The Piaggio IC.21(idro-caccia or hydro-fighter) was an attempt at realizing Ing. Pegna's theories in a coastal defense
interceptor. The clutch problems in the switch from water-propeller to air propeller were never fully resolved and as
a result the IC.21 squadriglia spent most of their career in waterborne mode as fast hydrofoils. The air propeller and
gearbox were finally removed to increase ammunition carriage for the two cowl mounted 20mm cannon.
The 'Pesce Volante' or 'Flying Fish' were popular with their, unfortunately water-bound but phlegmatic, pilots, however
they were hated by the maintenance crews. Not surprising as the aircraft were not equipped with a relief tube and when
on long patrols the pilots had a tendency to treat the bilges as a chamber pot, disregarding the standard issue empty
chianti bottles and funnel.

[PR19_Kit]

ROTFL! 

I like the title of that last pic! 'Afloat'? Only just!!

I didn't realise the thing sat so low in the water without the foils operating, but that must have meant they had a clutch for the aero prop or it would have thrashed the water to death till it came up above the surface.

[amsci99]

A bit off topic but alone the lines of a hyrofoil/hydroplane, the Idroscrivolante T108 at
http://www.alfabb.com/bb/forums/alfa-trucks-buses-marine-aviation-rail-industrial/48536-speedboats.html

[jcf]

ROTFL! 

I like the title of that last pic! 'Afloat'? Only just!!

I didn't realise the thing sat so low in the water without the foils operating, but that must have meant they had a clutch for the aero prop or it would have thrashed the water to death till it came up above the surface.

The clutch system was the downfall of the of the design, the problem of switching the engine power from driving the water propeller to the air propeller was never solved. Becoming foil-borne relied entirely on the thrust from the water propeller.

[PR19_Kit]

Becoming foil-borne relied entirely on the thrust from the water propeller.

That's what I figured, the water prop doesn't look man enough for the job at all.

Comparing its size with racing power boats of the era, which had similar horsepower engines, it needed to have been larger and had some more blades maybe. Even better to have more than one prop on the same shaft, like the 'Turbinia'

[jcf]

Becoming foil-borne relied entirely on the thrust from the water propeller.

That's what I figured, the water prop doesn't look man enough for the job at all.

Comparing its size with racing power boats of the era, which had similar horsepower engines, it needed to have been larger and had some more blades maybe. Even better to have more than one prop on the same shaft, like the 'Turbinia'

The marine prop size had nothing to do with the problems, prop and gearbox were tested in boats and performed very well.
The problem was with the clutch assembly in the aircraft, it continually filled with oil and skidded.

The comparison with a period racing boat isn't really relevant, they were single or multi-step hydroplanes and, for the most
part, very much larger and heavier, Gar Wood's Miss America X was enormous. They relied on the prop to get them on
plane and keep them there, the prop of the PC.7 was only to be required for a very short time, increasing the size would
have greatly increased drag. Also a small hydrofoil, which is what the PC.7 was when not flying, actually requires a surprisingly
small amount of power to become foil-borne. Sailing hydrofoils work quite well on wind-power alone.

http://www.foils.org/gallery/sail.htm



Jon

[PR19_Kit]

Sorry I even mentioned it........