Small(-ish) turbo-props

[PR19_Kit]

In The Loft I have an exquisite resin kit of a Shorts Sealand amphibian, made by the unlikely named 'Lift Here' company. In the RW the RAF never had any, Shorts only made 25 of them IIRC, but I'd like to change that, and fitting the Sealand C2 with some turboprops would seem to be a good idea. 

The Sealand's original engines were DH Gypsy Queens with an awe inspiring 340 bhp each    and (I can't help feeling that the smallest turbo-prop ever could do better than that! The question is, WHICH turbo-props would suit, and even are there any small enough? The 2nd question is, where would I get some in 1/72 scale?

The one that comes immediately to mind is the Astazou from a Jetstream, which would TRIPLE the available power output, but aren't available in model form as the Airfix Jetstream comes with the Garrett 331s ordered for the USAF C-10s which never happened. The Garret just doesn't have the style of the Astazou either.

So does anyone have any ideas where I could find a pair of Astazous or a suitable alternative?

[Flyer]

Does anybody kit the Shorts Tucano? It uses the Garrett TPF351, and is by the same company that makes the amphibian too.

Then there is the Pratt & Whitney Canada PT6 to consider too, it's used by heaps of light twins and singe engine aircraft, surely you can find some suitable nacelles from a Beechcraft King Air 350 or something...

Or... why not invent your own turboprop?

[PR19_Kit]

Yes, Airfix did the Tucano, and I've got a couple, but the cowling is huge compared to that of the Sealand's Gypsy Queens. It needs a long slim engine to fit the Sealand's styling.

A PT6 sounds good, yes, and I hadn't thought of that, goodness knows why not.    I'll have a dig around in the airliner area of The Loft and see if I have a suitable donor.

[Zero-Sen]

Don't you have any Airfix Short Skyvan (Garrett TPE331) or FMA Pucará (Astazou) hidden somewhere ?

[PR19_Kit]

Not a Skyvan, I wish I had, but I think I have  Pucara! I forgot that had Astazous, thanks very much. 

[jcf]

A Cessna L-19 was converted to use a Boeing 502 gas turbine and it didn't look all that different from a regular L-19. It was the first turboprop light aircraft and set an altitude record for light aircraft. It was designated XL-19B, two other L-19 were designated XL-19C and powered by the Continental 251, licensed Artouste.

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[jcf]

Gipsy Queen 70-3/70-4 (Short Sealand)
Length: 71.74 in
Width: 19.56 in
Height: 33.23 in
Weight: 698 lbs

Pratt & Whitney PT6A-6 Family
Length: 62 - 75 in
Width: 19.5 - 22.5 in
Height: 21 - 25 in
Weight: 456 - 595 lbs

Artouste IIIB
Length: 71.5 in
Width: 20 in
Height: 24.7 in
Weight: 340 lbs

Dimensionally a PT6A series or an Artouste III would fit within the nacelles of the Sealand, the weight
change would be the issue. Also as far as timeline is concerned the PT6 was first run in 1960 and had
its first flight test in 1961, it went into service in 1964. The original Artouste was first run in 1947 but
it was a less than 300 hp engine.

Based on the specifications perhaps lengthening the Sealand nacelles would work? Adding the length
in front of the leading edge of the wing. Widen the cooling air intake for the Gipsy Queen to work as
an engine air intake and then add an exhaust pipe. Just behind the propeller for a PT6 and exiting
over the wing for an Artouste?

Bryan Ribbins has a page of Sealand drawings over on Seawings including an original sales brochure:
Sealand on Seawings

[sandiego89]

This might be a great time to consider a scale-o-rama here:

- 1/144 Darts from a Viscount on your 1/72 aircraft.  Long and slim Darts look great.
- 1/144 Garrets from a  jet stream
- 1/144 Pucara
- 1/144 Bronco
etc

you probably have some in the stash.....

[McColm]

What about the Airfix De Havilland Heron,  I think the engines are small enough for what you have planned?

[The Rat]

PT-6 would be the best in my opinion. As for the timeline, well, it wouldn't be the first time that an aircraft design was resurrected with updated equipment. Or may it would be, but it has happened. Nuts, it's a whiff, the backstory can justify anything. 

[Weaver]

The Allison 250 is mostly thought of as a helicopter engine, but it's powered fixed-wings as a turboprop too.

Only specs on Wikipedia are for a turboshaft, so the weight's probably a bit low for a turboprop:

Length: 40.5 in (1,029 mm)
Diameter: 22.5 in (572 mm)
Dry weight: 138.5 lb (63 kg) dry

Power outputs can be anywhere from 300 to over 700 hp.
First ran in 1959, first production in mid 1960s.

[PR19_Kit]

What about the Airfix De Havilland Heron,  I think the engines are small enough for what you have planned?

Er, the Heron has the same engines as the Sealand, and they're not turbo-props.

I think the PT-6 would  work, and it fits the time line too, as would the Allison. I'll see what I've got in The Loft.

[The Rat]

Er, the Heron has the same engines as the Sealand, and they're not turbo-props.

I think the PT-6 would  work, and it fits the time line too, as would the Allison. I'll see what I've got in The Loft.

The de Havilland Gipsy Queen used on the Proctor had 210hp, so 2 would increase the Sealand's power by 80hp. But I still like the turbo idea.
https://en.wikipedia.org/wiki/Percival_Proctor#Specifications_(Proctor_IV)

[McColm]

As an alternative a pair of Elands from a Fairey Rotodyne, the Revell kit is smaller than the Airfix model and don't quote me but I think that they were turboprops.

[sandiego89]

The 1/200 4360's on the Spruce Goose are a great looking, long, slender, engine source.