Westland Whirlwind Whirling in my brain

[Leading Observer]

This may have been mooted before, but today the idea of the Westland Whirlwind fighter crossed with the DH Hornet popped into my mind. Is it feasible? Has anyone done it on here before?

[PR19_Kit]

I think so, at least one Merlin engined Whirlwind has appeared here in the past.

I've been doing an extreme version, a Griffon engined Welkin, for umpteen years now, and I may even finish it before one Christmas or another. 

[George the Cat]

I've been doing an extreme version, a Griffon engined Welkin, for umpteen years now, and I may even finish it before one Christmas or another. 

Is this a relative of the celebrated PR19 Meteor? 😉

[Leading Observer]

I think so, at least one Merlin engined Whirlwind has appeared here in the past.

I've been doing an extreme version, a Griffon engined Welkin, for umpteen years now, and I may even finish it before one Christmas or another. 

Now if we can get hold of 2 of Freightdogs Eagle Engine conversion sets an even more extreme Welkin becomes possible....

[PR19_Kit]

I've been doing an extreme version, a Griffon engined Welkin, for umpteen years now, and I may even finish it before one Christmas or another. 

Is this a relative of the celebrated PR19 Meteor? 😉

Well, it's got long wings for sure. 

Now if we can get hold of 2 of Freightdogs Eagle Engine conversion sets an even more extreme Welkin becomes possible....

Hell yes, they're BIG, and would probably suit the Welkin quite well. Let's hope Colin can re0furbish the tools for the Eagle.

[NARSES2]

I think so, at least one Merlin engined Whirlwind has appeared here in the past.

There's been a few Whirlwind variants posed here in the past. Must admit it's one of my favourite WWII aircraft and I keep meaning to build at least one of my Special Hobby kits 

I did this Merlin Mk V a few years ago now. Used 2 Italeri Spitfire Mk V engines.

You cannot view this attachment.

Here's the link to the build https://www.whatifmodellers.com/index.php?topic=45532.0

[PR19_Kit]

Ah yes, that does look rather splendid Chris. 

And SO logical too, I'm sure they wouldn't have missed the relatively few Merlins it would have taken to put them on all the Whirlwinds, and it would have improved their performance no end.

[NARSES2]

Ah yes, that does look rather splendid Chris. 

And SO logical too, I'm sure they wouldn't have missed the relatively few Merlins it would have taken to put them on all the Whirlwinds, and it would have improved their performance no end.

I've always read that it was more down to Petter's insistance on continuing with a developed Peregrine ?

Interesting extract from Wikki' :-

Despite the Whirlwind's promise, production ended in January 1942, after the completion of just 112 production aircraft (plus the two prototypes). Rolls-Royce needed to concentrate on the development and production of the Merlin engine, and the troubled Vulture engines, rather than the Peregrine. Westland was aware that its design – which had been built around the Peregrine – was incapable of using anything larger without an extensive redesign.

After the cancellation of the Whirlwind, Petter campaigned for the development of a Whirlwind Mk II, which was to have been powered by an improved 1,010 hp (750 kW) Peregrine, with a better, higher-altitude supercharger, also using 100 octane fuel, with an increased boost rating. This proposal was aborted when Rolls-Royce cancelled work on the Peregrine. Building a Whirlwind consumed three times as much alloy as a Spitfire

[PR19_Kit]

I wonder what the 'extensive re-design' would have been? A Peregrine wasn't all THAT different to a Merlin.

[zenrat]

I wonder what the 'extensive re-design' would have been? A Peregrine wasn't all THAT different to a Merlin.

A Merlin weighed approximately 50% more than a Peregrine.  Putting a pair on the same firewalls as the Peregrines would have had CoG consequences and ISTR Whirlwinds already had a big chunk of ballast in the tail...

[Old Wombat]

The biggest issue was the weight, two Merlins would weigh about 1,000 lbs more than the two Peregrines, so would seriously effect the CoG.

Specifications (Peregrine I)
Data from Lumsden, Gunston & Wilkinson

General characteristics

    Type: 12-cylinder supercharged liquid-cooled 60-degree Vee aircraft piston engine
    Bore: 5 inches (127 mm)
    Stroke: 5.5 inches (139.7 mm)
    Displacement: 1,296 in3 (21.2 L)
    Length: 73.6 in (1,869 mm)
    Width: 27.1 in (688 mm)
    Height: 41.0 in (1,041 mm)
    Dry weight: 1,140 lb (517 kg)

Performance

    Power output:
        Take-off rating: 765 hp (570 kW) at 3,000 rpm at ground level
        Max combat rating: 960 hp (720 kW) at 3,000 rpm at 12,000 ft (3,700 m)
        Max continuous rating: 860 hp (640 kW) at 2,850 rpm at 13,500 ft (4,100 m)
        Max cruise rating: 730 hp (540 kW) at 2,600 rpm at 13,500 ft (4,100 m)
    Specific power: 0.68 hp/in3 (31.1 kW/L)
    Compression ratio: 6:1
    Power-to-weight ratio: 0.77 hp/lb (1.28 kW/kg)


Specifications (Merlin 61)
Data from Jane's.

General characteristics

    Type: 12-cylinder, supercharged, liquid-cooled, 60° "Vee", SOHC, piston aircraft engine.
    Bore: 5.4 in (137.2 mm)
    Stroke: 6.0 in (152.4 mm)
    Displacement: 1,649 cu in (27.0 L)
    Length: 88.7 in (225.3 cm)
    Width: 30.8 in (78.2 cm)
    Height: 40 in (101.6 cm)
    Dry weight: 1,640 lb (743.9 kg)

Performance

    Power output:
            1,290 hp (960 kW) at 3,000 rpm at take-off.
            1,565 hp (1,167 kW) at 3,000 rpm at 12,250 ft (3,730 m), MS gear)
            1,580 hp (1,180 kW) at 3,000 rpm at 23,500 ft (7,200 m), FS gear)
    Specific power: 0.96 hp/cu in (43.6 kW/L)
    Compression ratio: 6:1
    Fuel consumption: Minimum 30 Imp gal/h (136 L/h), maximum 130 Imp gal/h (591 L/h)
    Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg) at maximum power.

NOTE: The period appropriate Merlin III & Merlin XII (& the Merlin XX, for good measure) had different performance statistics;

    Merlin III (RM 1S) - 1,310 hp (980 kW) at 3,000 rpm at 9,000 ft (2,700 m) using 100-octane fuel; using 87-octane fuel the power ratings were the same as the Merlin II. First production Merlin III delivered 1 July 1938.

    Merlin XII (RM 3S) - 1,150 hp (860 kW); used 70/30% water/glycol coolant rather than 100% glycol. Reinforced construction First production Merlin XII, 2 September 1939.

    Merlin XX (RM 3SM) - 1,480 hp (1,100 kW) at 3,000 rpm at 6,000 ft (1,800 m); two-speed supercharger; boost pressure of up to +14 psi. First production Merlin XX, 4 July 1940.


While on paper they look similar, it needs to be noted that the Peregrine was the tail end of Kestrel development &, according to Rolls Royce, was nearing the absolute maximum performance it would ever be able to generate from that family, while the Merlin was at the beginning of its development cycle & had much more promise.

[PR19_Kit]

Petter should have taken a leaf out of my Rule Book, and made the fuselage longer. 

[Weaver]

Kit beat me to it about making the fuselage longer.

Another trick would have been to put belt-feed Hispanos in a belly pack, with the majority of the weight further back, and ammo above their breaches behind the fuselage tanks. That would have the added advantage of not blinding the pilot with muzzle flash.

It must be possible to make a compact twin-Merlin fighter because the DH Hornet existed. The Hornet was only three feet longer than the Whirlwind and had exactly the same span. It did have 30% more wing area (for marginally less wing loading) though.

Hornet:
Length: 35 ft 6 in (10.82 m)
Wingspan: 45 ft 0 in (13.716 m)
Height: 14 ft 2 in (4.32 m)
Wing area: 361 sq ft (33.5 m2)
Empty weight: 11,292 lb (5,122 kg)
Wing loading: 43.82 lb/sq ft (213.9 kg/m2)

Whirlwind:
Length: 32 ft 3 in (9.83 m)
Wingspan: 45 ft 0 in (13.72 m)
Height: 11 ft 0 in (3.35 m)
Wing area: 250 sq ft (23 m2)
Empty weight: 8,310 lb (3,769 kg)
Wing loading: 45.6 lb/sq ft (223 kg/m2)

Data from Wikipedia.

[perttime]

If you want to put more weight in a Whirlwind, in the form of heavier engines, you need more wing too. Or new lift enhancement technologies.
I recall Whirlwind landing speed was pretty hot in real world.

[jcf]

The single-speed, single stage Merlin that would have been available in the period is shorter in length than the Peregrine, 69" vs. 73.6", and "only" 235 lbs. heavier, 1,375 lbs vs. 1,140 lbs. The length difference is primarily due to the downdraft carburetor that sticks out from the rear of the supercharger on the Peregrine. It's not as neat as the updraft carburetor installation of the Kestrel and Merlin. A primary visual difference of a Merlin Whirlwind would be an air intake on the underside of the nacelle.

Speaking of Merlins, early evening yesterday one nailed a dove in our backyard. It was easily visible from the living room and we watched it ripping
away for about 25-30 minutes.