Light fighters alternatives, 1935-1945 (2 Viewers)

I have found out that tapared swept wings made of wood are somewhat tricky to make. Not impossible.
Not impossible indeed :)
 
They did?

Not quite. There were several iterations of different concepts for the aircraft, the fastest of which had a theoretical calculated max. speed in level-flight of 682 kmh. See also my post on the project on page 5 of this thread here.

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Source: Jukka Raunio (2007): Valtion Lentokonetehtaan Historia, Osa 2: Tampereella ja sodissa 1933-1944, pp. 237-240.

Considering the mid-air disintegrations that plagued the Myrsky project, which were a result of Finland lacking the capability to produce high-grade adhesive film, among other things, it's difficult to imagine the Puuska would've faired any better.
 
Not quite. There were several iterations of different concepts for the aircraft, the fastest of which had a theoretical calculated max. speed in level-flight of 682 kmh. See also my post on the project on page 5 of this thread here.

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Source: Jukka Raunio (2007): Valtion Lentokonetehtaan Historia, Osa 2: Tampereella ja sodissa 1933-1944, pp. 237-240.

Considering the mid-air disintegrations that plagued the Myrsky project, which were a result of Finland lacking the capability to produce high-grade adhesive film, among other things, it's difficult to imagine the Puuska would've faired any better.
Which air foil was it to use ?

VL Pyörremyrsky oli Valtion Lentokonetehtaan suunnittelema toisen maailmansodan aikainen suomalainen hävittäjälentokone. Jos etsit tietoa koneen siiven aerodynamiikasta ja siipiprofiilista (engl. wing airfoil), sen tekniset tiedot ovat: [1]
    • Siipiprofiili tyvessä: NACA 23015
    • Siipiprofiili kärjessä: NACA 23009
    • Siiven kärkiväli: 10,38 metriä
    • Siiven pinta-ala: 19 m² [1, 2, 3]

    Same as Pyörremyrsky ?
YAK-3 had Clark YH.
 
I don't have time to wade into this now, but I can roughly sketch out a premise:

We have the assumption in the Anglophone world (and the multi-lingual but Anglophone adjacent worlds ;) ) that more power, more guns, more armor was the only way to victory in WW2. I don't think that is necessarily the case though, and a let's say 'revisionist' approach to the history of aircraft like the A6M, Ki-43, MC 202, Yak-1B, Yak 3, La 5FN etc., and then by contrast the P-47, Typhoon, Bf 110 / 210 / 410, Ki-45, yes even the Corsair and P-38 based on their operational histories, tells us that perhaps there was another way- a lighter way.

Operational history tells us that lighter aircraft with fewer guns and a bit less speed or high altitude dominance could also be effective. Whether you needed to be highest and fastest in every scenario depended a lot on the nature of the battlefield and the Theater. Strategic bombing campaigns were not the only way to victory, and where there was a big ground war (or a naval war) going on below the skies, tactical bombers and attack aircraft were much more important (arguably) than big high flying heavy bombers. Which meant that fighters needed to be able to perform better down low, and needed to be agile enough to win sustained fights around the smaller tactical dive bombers and attack planes.

So there are two tiers to this perhaps. First, we have the known to be successful 'lighter fighters', then we have the more experimental truly 'light fighters' with smaller engines, less guns, maybe non-strategic materials etc., which for the most part, never got real investment or were abandoned by the later war. These would generally be under 3,000 kg gross weight, mostly not used or saw minimal action during the war, mostly using smaller than typical engines (sometimes really achieving a lot in terms of speed with quite small engines ~500 hp etc.) and with small production ranging from just a prototype to maybe 300 or 400 produced. There is obviously some overlap between the two groups, as anything which saw widespread military service goes in the first group.

I probably missed quite a few but I'm out of time ... this gives us something to think about though.

Lighter Fighters might include:
A5M
...
I am reading back through the early messages of this thread. We are having difficulties defining lightweight fighters.

From the mid-thirties to the end of WWII, the engines increased in displacement and power, and the guns got bigger and more numerous. Aircraft like the Mitsubishi A5M and the Curtis P36, developed in the thirties, used the biggest available engines, and if not (relatively) massive firepower, their armament was at least conventional. However light they were later in the war, they were conventional back in their day.

It's 1943, and the Billy Bob and Cousin Elmo aircraft company sets to work developing a lightweight fighter. In 1943, BBCE can design around the Pratt & Whitney R1830 in preference to the now available and reliable R2800. I think that less than four M2 0.5" machine guns is not a good idea. To keep the aircraft as tiny as possible, we give up high altitude performance, and range. If the aircraft is really tiny, it will have good acceleration and climb. The aircraft would be useful for tactical air superiority, and for light bombing tasks. Presumably, you would have lots of them.

I don't see how any of this works outside of the USA. Great Britain's small, early war engine was the Merlin. The Rolls Royce Kestrel and Bristol Pegasus were well under 1000hp, and not suitable for a 1943 fighter. Firepower can be reduced to a pair of 20mm Hispanos. The Germans did not have a dinky early war engine. Both the Bf109 and the Fw190 were tiny aircraft. Japanese fighters were lightweight by 1943 standards, and they desperately needed to develop big, powerful fighters, with armour protection, and the firepower to knock down American four engined bombers. Like the Germans, they failed to develop high altitude fighters.
 
Puuska was to be 9% smaller than Yak-3...and 30% smaller than Pyörremyrsky.
 
Nobody has mentioned the Ambrosini SAI.403. This was lightweight by mid-war standards and made of wood. The Germans and Japanese were impressed by its performance, although I have my doubts about a war-ready aircraft doing 403mph.
I'd share your doubts about that turn of speed, especially since the similar SAI.207 did only 575 km/h (under 360 mph).
Also, stuff coming from Green of the 1960s/70s is another red flag.
 
I'd share your doubts about that turn of speed, especially since the similar SAI.207 did only 575 km/h (under 360 mph).
Also, stuff coming from Green of the 1960s/70s is another red flag.
The single prototype (MM.518) was seized by the Germans and evaluated by the Luftwaffe at Vergiate. Japanese pilots then stationed in Germany were also given a chance to fly the aircraft, with the result that it was ordered into production by both Heinkel and Mitsubishi.[citation needed]​ None of these flew before the end of the war.

I tried with help of the AI construct a plane that would propel itself into 870 km/h speed at high. According to AI and my calculations of the drag it was 675 hp...the need for HPs....so Ambrosini at 750 hp was plenty to go 650 km/h. My design was way more streamlined than that Dardo was....with a TIO -550 it could do 680 km/h. With a souped up Corvair on supercharger (180 hp) 450 km/h. 275 hp engine gave top speed of 550 km/h.
 

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The single prototype (MM.518) was seized by the Germans and evaluated by the Luftwaffe at Vergiate. Japanese pilots then stationed in Germany were also given a chance to fly the aircraft, with the result that it was ordered into production by both Heinkel and Mitsubishi.[citation needed]​ None of these flew before the end of the war.

I tried with help of the AI construct a plane that would propel itself into 870 km/h speed at high. According to AI and my calculations of the drag it was 675 hp...the need for HPs....so Ambrosini at 750 hp was plenty to go 650 km/h. My design was way more streamlined than that Dardo was....with a TIO -550 it could do 680 km/h. With a souped up Corvair on supercharger (180 hp) 450 km/h. 275 hp engine gave top speed of 550 km/h.
Your AI is hallucinating. 870kph is 545mph, faster than any piston engined aircraft has ever gone in level flight.

I have my copy of William Green's War Planes of the Second World War -- Fighters Volume_2 (sorry Tomo Pauk), with its article on he calls the S.A.I.403 Dardo. The top speed is quoted as 403mph at 23,620ft. This converts to 645kph at 7,200m. Green did not understand decimal accuracy. I see that the earlier S.A.I.207 did 398mph at 14,765ft (635kph at 4,500m). These numbers are truly spectacular for 750hp. I wonder if the 7200m altitude is a typo. Wikipedia's article on the Isotta Fraschini Delta engine says it got 750hp at 4,000m (13,000ft), which makes sense with its single stage supercharger.

The Isotta Fraschini Delta was an inverted V12, and it was air cooled. Meredith effect requires a liquid radiator. The de Havilland Albatross had some clever jiggerypokey with its inverted, air cooled V12s sucking air in at the wing roots and feeding it forwards. I don't know how well this worked. The Dardo had its cooling duct at the front. Successful air cooled engines were bigger than the successful liquid cooled engines during WWII, probably due to cooling.
 
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The single prototype (MM.518) was seized by the Germans and evaluated by the Luftwaffe at Vergiate. Japanese pilots then stationed in Germany were also given a chance to fly the aircraft, with the result that it was ordered into production by both Heinkel and Mitsubishi.[citation needed]​ None of these flew before the end of the war.

I tried with help of the AI construct a plane that would propel itself into 870 km/h speed at high. According to AI and my calculations of the drag it was 675 hp...the need for HPs....so Ambrosini at 750 hp was plenty to go 650 km/h. My design was way more streamlined than that Dardo was....with a TIO -550 it could do 680 km/h. With a souped up Corvair on supercharger (180 hp) 450 km/h. 275 hp engine gave top speed of 550 km/h.
Notice that caption "citation needed" in the first paragraph? That's because the author is full of fantasy. The SAI.207 was a failure.

The pilots who flew it hated it, it suffered from low power, high wing loading and a fragile frame that prevented heavier armament (heavy recoil cause frame damage). And after three years of "debugging" (introduced in 1940), it still was not performing as the Italians had hoped.

If you insist on using AI and wiki as a resource, you will not get anywhere.
 
The single prototype (MM.518) was seized by the Germans and evaluated by the Luftwaffe at Vergiate. Japanese pilots then stationed in Germany were also given a chance to fly the aircraft, with the result that it was ordered into production by both Heinkel and Mitsubishi.[citation needed]​ None of these flew before the end of the war.

I tried with help of the AI construct a plane that would propel itself into 870 km/h speed at high. According to AI and my calculations of the drag it was 675 hp...the need for HPs....so Ambrosini at 750 hp was plenty to go 650 km/h.
As noted by the above posters, AI and Wikipedia is meh.
I have my copy of William Green's War Planes of the Second World War -- Fighters Volume_2 (sorry Tomo Pauk), with its article on he calls the S.A.I.403 Dardo. The top speed is quoted as 403mph at 23,620ft. This converts to 645kph at 7,200m. Green did not understand decimal accuracy.

See here for 575 km/h figure for the SAI.207.
Green's books have run their course.
 
Your AI is hallucinating. 870kph is 545mph, faster than any piston engined aircraft has ever gone in level flight.

I have my copy of William Green's War Planes of the Second World War -- Fighters Volume_2 (sorry Tomo Pauk), with its article on he calls the S.A.I.403 Dardo. The top speed is quoted as 403mph at 23,620ft. This converts to 645kph at 7,200m. Green did not understand decimal accuracy. I see that the earlier S.A.I.207 did 398mph at 14,765ft (635kph at 4,500m). These numbers are truly spectacular for 750hp. I wonder if the 7200m altitude is a typo. Wikipedia's article on the Isotta Fraschini Delta engine says it got 750hp at 4,000m (13,000ft), which makes sense with its single stage supercharger.

The Isotta Fraschini Delta was an inverted V12, and it was air cooled. Meredith effect requires a liquid radiator. The de Havilland Albatross had some clever jiggerypokey with its inverted, air cooled V12s sucking air in at the wing roots and feeding it forwards. I don't know how well this worked. The Dardo had its cooling duct at the front. Successful air cooled engines were bigger than the successful liquid cooled engines during WWII, probably due to cooling.
Sure it is faster than any piston aircraft....and why ?

Cause no one has designed such...and build one.

One was designed.


You need to consider the new speed regime...that comes with high speeds...the transonic region.

But when you load it with cannons and ammo...it needs a lot of hps.

Just outside hanging tail wheel costs 10 mph even at 600 km/h region.


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Dardo may have hit 650 in a tail wind or shallow dive...who knows.


Stenautti was ahead of his time anyway....the designer.
 
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A non existing aircraft has a speed of exactly zero km/h.


'Who knows' is the equivalent of 'trust me, bro'.


Source?
Sergio was a know canard aeroplane designer.

Sergio Stefanutti was an Italian engineer who pioneered the canard aircraft configuration in Italy during the 1930s, designing a series of experimental aircraft before his most famous fighter prototype. His work began with light aircraft like the SS.1 (1934), SS.2 (1935), and SS.3 Anitra (1937), which served as testing grounds for tail-first aerodynamics.

These experiments culminated in the SAI-Ambrosini SS.4, the first Italian canard fighter, developed in the late 1930s. This all-metal, single-seat prototype featured a pusher propeller, retractable tricycle landing gear, and twin fins mounted on the main wing's trailing edges. Although it offered excellent pilot visibility and stable handling qualities during tests in 1940–1941, the sole prototype was lost in a crash on its second flight in March 1939, halting further development.

Stefanutti continued to innovate in post-war aviation, designing the Aerfer Sagittario 2, which became the first Italian aircraft to break the sound barrier. His legacy is defined by his early and persistent application of canard and pusher layouts, predating similar popularizations by decades.



View: https://www.youtube.com/watch?v=lq-zq253ipg

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Physics apply.
 
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Thank you.

FWIW, I do like the 'normal' Ambrosini fighters' idea - a small, sleek fighter, powered by a legacy V12 engine. Not everyone was able to aford the all-singing, all-dancing powerful and expensive fighters. His application of wood, and supposed ease of manufacturing - at least when compared with the other Italian fighters that were notoriously time-consuming to make - was also a benefit.
Problem with this is that the idea was too late. If Italians, or other people wanting to make a similar design, were to start actually making prototypes already after 1935, by 1939/40 they would've have these fighters in decent numbers.
 

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