1935-45: airforce on a tight budget & schedule

[tomo pauk]

Everybody and his brother were trying to have as good as aiforce/air-service as possible, and especially in the specified time frame, but many times the available budget was a serious brick wall between the desires and reality. What kind of aircraft should a not-rich, but a reasonably developed country (like Czechoslovakia, Poland, Sweden, Belgium, Yugoslavia, Romania, even Italy) try to purchase? Even if it means combining foreign bits & pieces with home-grown stuff? Wanted are cheap & cheerful, yet capable fighters and bombers. No biplanes, not even the strutted monoplanes - save the money on other places.
'Make' the engines you want, but something that is plausible for the time frame. Don't go awry with numbers of cylinders on the engine, like 16, 18 or 24, that will make the engine purchase expensive.
Note that there is a lot of outdated biplanes/strutted monoplanes in need of replacement, so having the affordable designs in the backburner is not out of the place for France, UK, Japan or Soviet Union. Americans can pay for turbochargers, so keep that in mind.

Note that not the budget is tight, but also the schedule - we never know when an big-mouthed neighbuor might decide to act upon the big words.

 

[riggerrob]

One factor is reducing the number of prototypes built. Sure, air forces need to test out new concepts like turret-fighters (BP Defiant and Blackburn Roc), but those bizarre concepts should only be built in small numbers and only test-flown until lessons-learned become obvious.
Then shift development to the best-performing airplane in each class.
Small nations like Belgium could only afford a single type of single-engined fighter, say Renaud for example.

 

[Apophenia]

Not sure this is what you meant, but here goes ...

Since a 'big-mouthed neighbour' has been identified as a potential opponent, I'm going to eliminate Italy from my list.

Belgium

Belgian airframers had too many projects for the nation's size. SABCA signed a marketing and production deal with Caproni in Oct 1937 (whichmight be viewed as a security threat). Nationalisation of SABCA would eliminate its Caproni connections.

In this scenario, there are no orders for foreign Fiat CR.42s, Gladiators, Hurricanes, or Battles.

Fighters

- Renard: 1937 R.36; ordered straight off the drawing board
-- R.36: 1 x 860 hp Hispano Suiza 12Ycrs; 3 x 13.2 FN hmgs
-- Renard would be assembling parts from outside suppliers*
-- * Who, hopefully, could ID potential airframe weaknesses

- Renard: 1938 R.38; ordered as R.26 development/follow-on*
-- R.38: 1 x 1,030 hp Rolls-Royce Merlin II; 4 x 13.2 FN hmgs
-- * Backup R.37A (640 hp Kestrel V) rejected; prototype only

Recce-Bomber

- Avions Fairey: Faucard, whif monoplane Fox deriv.*
-- R.38A: 1 x 860 hp HS 12Ybrs; 3 x 7.62mm FN-Brownings
-- R.38B: 1 x 1,030 hp RR Merlin II; 1 x 2 x 13.2 FN hmgs
-- * Modified Fox-fuselage as low-winged 'Mini-Battle'

Bomber

- SABCA: Bristol Blenheim Is assembled at Haren-Evere

- SABCA: (Project) Breguet Br.694 A3B2 assembled at Haren*
-- * As RW but order backdated for deliveries by May 1940

__________________________________________

Czechoslovakia

Too many firms chasing for too few production contracts - concentration/rationalisation required. CzAF focused
excessively on army co-op, recce-bombers, & other light combat types. In this scenario, no license for Soviet Tupolev SB bomber.

Czechoslovak aero-engine industry is also spread over too many competing types (especially at the small end). Most critical is getting Hispano types right. Have ČKD license-build HS 12Ycdr/drs series aero-engines while Avia focuses on evolving their 1,000 hp variant - while employing simplified construction techniques (to eliminate Marc Birkigt's dedicated tooling requirement).

Fighter

- Avia Av.36: Whif B.534-based monoplane (eclipsing Av.35/Av.135)
-- Av.35A: 1 x 860 hp Avia HS 12Ycrs; 2 x 7.9 + 1 x 20 mm FFS gun
-- Av.35A: 1 x 1,000 hp Avia 12Y-1000C; 2 x 7.9 + 1 x 15 mm ZB
-- Modified B.534 fuselage; Av.135 wings, retractable undercarriage*
-- * A Messier versus Dowty competition to design a retractable u/c

Recce-Bomber

- Praga E-53-II: Twin Avia HS 12Ycrs-powered alternative to lighter E-51

Bomber

- Aero Vodochody: A.300; 2 x 820 hp Walter (Bristol) Mercury IXs
-- Also whif A.204V twin trainer w/ max. A.300 airframe commonality

__________________________________________


Poland

Usual drill ... too many concept and designs; too much focus on lightweight concepts - eg: RWD-25, etc.

A desire for indigenous aero-engine designs is understandable (technically and economically). But airframe designs with untried engines should include back-ups. In other words, the PZL-38 and PZL-48 should have been designed concurrently. That said, I would suggest that Poland should have developed expertise in retractable undercarriage design at an earlier stage.

Fighters

- PZL.41: 1938 whif; low-winged monoplane fighter*
-- PZL.41: 1 x 840 hp PZL Mercury VIII; 4 x wz.36
-- * Effectively a Mercury-powered Polish IAR 80
-- * PZL.50 cancelled for excessive development time

- PZL P.11g: 1938 Kobuz; rebuild of P.11c airframes*
-- PZL P.11g: 1 x 840 hp PZL Mercury VIII; 4 x wz.36
-- * RW P.11g but backdated conversions not new-builds

Recce-Bombers

- PZL-46A: 1939 whif Sum; as RW but with retr. u/c
-- PZL-46A: 1 x 970 hp PZL WS Pegaz XX; 4 x wz.36*
-- * 2 in cowl, 2 in wings + 4 x wz.37 on flex mounts

- PZL-48: 1939 Lampart; 2 x 730 hp GR 14M-07/-08s*
-- * As RW but backdated for earlier airframe prod'n start

Bombers

- PZL.37B - Łoś; 2 x 970 hp PZL WS Pegaz XX; 3 x wz.37

__________________________________________

Romania

Fighter

- IAR-80A: 1939; 1 x 870hp IAR K14-III C32; 4 x 7.92mm FN-Browning

- IAR-80B: 1941; 4 x 7.92mm FN-Browning + 2 x 13.2mm FN-Browning

Recce-Bombers

- IAR-47A: 1939 whif low-winged monoplane 2-seat recce-bomber*
-- IAR-47A: 1 x 960 hp IAR 14K IV C32; 4 x 7.92mm FN-Brownings
-- IAR-47B: 4 x 7.92mm FN-Brownings + 2 x 13.2mm FN-Brownings
-- * RW 1942 project backdated to replace IAR-37 recce biplane

Bombers

- IAR SM-79B: 1939 whif; locally made; 2 x 960 hp IAR 14K radials*
-- * Locally-built versions of Savoia-Marchetti-built original order

- IAR JRS-79B: 1941; RW locally-made; 2 x 1,200 hp Jumo 211Da

__________________________________________

Sweden

Sweden was quick to shift from mixed-construction to all-metal types. For quicker local production, that could have been scaled back. It would also help to make use of indigenous materials - eg: wood and steel-tubing.

Fighters

- CVA : J 19; 1939 whif Fokker D.XXI production as a 'Nödjakt'*
-- 1 x 980 hp Nohab My XXIV Mercury; 4 x 8 mm m/22 mgs
-- * 'Emergency-Fighter' intended for FI use but retained by SE
-- * Designation free (no Swedish use of Fiat CR.42 - all to FI)

- FFVS: J 20; 1940 whif; Bo Lundberg's 1939 Götaverken GP 9 design*
-- 1 x SFA R-1830-STWC-3; 2 x 8 mm m/22 + 2 x 13.2 mm m/39A
-- * RW Götaverken GP 9 design matured into FFVS J 22 fighter
-- * Designation free (no Swedish Reggiane Re.2000 purchase)

Divebombers

- SAAB: RW B 17 light-/divebomber design (based on ASJA L 10)
-- 1 x 980 hp Nohab My XXIV or 1 x 1,065 hp SFA R-1830-STWC-3

- ASJA: B 5B; Northrop 8A-1 light-/divebomber; 1 x Nohab My XXIV
- SAAB: B 5C; Northrop 8A-1 light-/divebomber; 1 x Nohab My XXIV

Recce-Bombers

- CVM : 1940 S 26; licensed Fokker G.I; 2 x Nohab My XXIV Mercurys
-- RW procurement choice but orders backdated for earlier delivery

- SAAB: RW S 17 light recce-bomber design (based on ASJA L 10)
-- 1 x 980 hp Nohab My XXIV or 1 x 1,065 hp SFA R-1830-STWC-3

Bombers

- SAAB: 1944 B 18A; 2 x x 1,065 hp SFA R-1830-STWC-3

- CVA/CVM: B 16A; 1940 whif; 2 x 930 hp Bristol Pegasus XXVI*
-- Whif hybrid Fokker T.V (wings, nacelles) + T.IX (fuselage, tail)
-- * Designation free (no Swedish Caproni 313S purchase)

- SAAB: B 3C; RW licenced Junkers Ju 86K; 2 x Nohab My XXIVs

__________________________________________

Yugoslavia

Fighters

- Rogožarski IK-3: 1940 low-winged monoplane fighter*
-- IK-3: 1 x 980 hp Avia 12Ycrs; 2 x 7.92 mm + 1 x 20 mm FF
-- * As per RW IK-3 but more intensive production rate

Recce-Bombers

- Rogožarski R-313A: 1940 whif twin-engine 'destroyer'*
-- R-313A: 2 x Avia 12Ydrs; 2 x 7.92 mm; 2 x 20 mm FF
-- * As RW R-313 but w/ higher-powered engines

Bombers

- Imported Savoia-Marchetti SM.79s & Dornier Do 17Ka-2s
___________________________________

 

[Unstart]

Sweden was quick to shift from mixed-construction to all-metal types. For quicker local production, that could have been scaled back. It would also help to make use of indigenous materials - eg: wood and steel-tubing.

___________________________________

I really like the FFVS J22 design as a late 1930s fighter. Performance seems very good; http://web.archive.org/web/20120223140906/http://www.hobbybokhandeln.se/j22/22perf.htm

And since it used an R-1830 and has wood/steel tube construction as mentioned I can't see why it wouldn't be feasible for someone like the US or UK to come up with something similar in the late 30s.

 

[riggerrob]

Dear Apophenia,
You make some good points about rationalizing production by reducing the numbers of different designs.
Are you suggesting that Poland should have developed their gull-winged monoplanes into something more like the low-winged Romanian I.A.R.?

May I suggest narrowing the focus of inline engines to Hispano-Suiza 12Y?
This would allow mounting a single 20mm auto-cannon as faster, all-metal bombers were being introduced. With barely 1,000 hp. late-1930s fighters could barely loft a single cannon. Look how successful So jets were with their HS engines built under license by Klimov. HS engines had plenty of growth potential. By 1942, Klimov VK-107B was pumping out 1,800’hp.

 

[Apophenia]

I really like the FFVS J22 design as a late 1930s fighter. Performance seems very good; http://web.archive.org/web/20120223140906/http://www.hobbybokhandeln.se/j22/22perf.htm

And since it used an R-1830 and has wood/steel tube construction as mentioned I can't see why it wouldn't be feasible for someone like the US or UK to come up with something similar in the late 30s.

Me too. And I can see this type (or my what-if J 20/Götaverken GP 9) being offered to the Finns to replace D.XXI production at VL as well.

 

[Apophenia]

...Are you suggesting that Poland should have developed their gull-winged monoplanes into something more like the low-winged Romanian I.A.R.?

May I suggest narrowing the focus of inline engines to Hispano-Suiza 12Y?
This would allow mounting a single 20mm auto-cannon as faster, all-metal bombers were being introduced. With barely 1,000 hp. late-1930s fighters could barely loft a single cannon. Look how successful So jets were with their HS engines built under license by Klimov. HS engines had plenty of growth potential. By 1942, Klimov VK-107B was pumping out 1,800’hp.

riggerrob: Yes, 'Jaki' Jakimiuk's PZL.50 was potentially a fine design but, as history showed, it simply took too long to develop. So, leave Jastrząb development until the Hercules engine was available - which we know (with 20/20 hindsight) never happened.

Since, in OTL, a much less-experienced IAR Brașov design team was able to produce the P.24-derived IAR-80, why not have Jakimiuk do the same? Less development time involved, same engine as the RW P.11g Kobuz.

HS 12Y: Agreed on the possibilities of the Hispano Suiza. But, in its original form(s), the RW HS 12Y never lived up to its potential (and the post-WW2 HS 12Z had reliability problems). IIRC, part of the HS 12Y's issue was low rpms and its Turbomeca supercharger. But I've also read that Birkigt's obsession with dedicated, proprietary tooling also limited development. Others may know better (and ATLs would be so much simpler if I was proven wrong).

Specifically about Avia I was proposing Klimov-like modifications and simplification. However, all eastern European airframe makers experience difficulties in procuring HS 404s and ended up falling back on the indifferent Oerlikon FF series. That was why I proposed that Czechoslovakia rely on its own, excellent armaments industry to produce an aircraft gun chambered for the 15x104mm Brno cartridge (as per the ZB 60). The HS 404 would be superior ... but it was never available.

The brief was designing airframes but, for Poland and Romania, there was another angle to be played. With Romania being a major oil producer (by European standards), what if they (and/or Poland) built refineries dedicated to producing higher octane aviation fuels? RW, the introduction of 100 octane for the RAF made a big difference during the Battle of Britain. So, what if similar fuels had been available to the Poles in September 1939?

As part of Royal Dutch Shell, Astra Romano would seem the obvious candidate for such a refinery. Adopting such fuels would mean higher outputs for new engine types - with PZL perhaps adopting the Mercury XV for production rather than the 87 octane Mercury VIII. Then, existing service engines - like the PZL Mercury VI S2 - might be modified to take increased manifold pressure (possibly bringing them closer to Mercury VIII power outputs). If these changes were in effect by the Summer of 1939, it would have made a big difference in the Poles fight with the Nazis.

 

[tomo pauk]

HS 12Y: Agreed on the possibilities of the Hispano Suiza. But, in its original form(s), the RW HS 12Y never lived up to its potential (and the post-WW2 HS 12Z had reliability problems). IIRC, part of the HS 12Y's issue was low rpms and its Turbomeca supercharger. But I've also read that Birkigt's obsession with dedicated, proprietary tooling also limited development. Others may know better (and ATLs would be so much simpler if I was proven wrong).

Turbomeca's S/C was the best part of the HS-12Y-45 (and -49), but these were just being introduced on the D.520s. The MS 405/406 were powered by the -31 engines with the old, legacy S/C made by the parent company (HS). Difference was big, talk ~200 HP more for the -45; power surplus was at all altitudes. The -45s S/C construction that employed variable guide vanes enabled it to have the power surplus also on the low altitudes (1-speed S/Cs that offer better hi-alt power usually sacrifice the low-altitude power).
(dashed lines are power, full lines are manifold pressure)



H-S have had the -51 in the works, with crankshaft with ballances in order to turn extra 100 rpm, but it was a lo-ish altitude engine that made it's 1000 HP at some 3000 meters IIRC. Mating the -51 with the Turbomeca S/C would've provided a very good engine for the needs of 1940, if not for 1941, but even the -51 was too late in production to matter.

Specifically about Avia I was proposing Klimov-like modifications and simplification. However, all eastern European airframe makers experience difficulties in procuring HS 404s and ended up falling back on the indifferent Oerlikon FF series. That was why I proposed that Czechoslovakia rely on its own, excellent armaments industry to produce an aircraft gun chambered for the 15x104mm Brno cartridge (as per the ZB 60). The HS 404 would be superior ... but it was never available.

HS 404 was too late, even the French were still using the licence-manufactured cannons of Oerlikon design in 1940. Supplying the 404s to the E. European conutries was nigh impossible.
Oerlikon cannons were the best 20mm cannons in the world before 1939-ish, and were still very usable in any ww2 year - calling them indifferent is selling them short.

It took Klimov until 1941 to sort-out the HS 12Y, that included opting for smaller bore so the block is stronger, introduction of a 2-speed S/C, introduction of new valve train with 3 valves per cylinder.

The brief was designing airframes but, for Poland and Romania, there was another angle to be played. With Romania being a major oil producer (by European standards), what if they (and/or Poland) built refineries dedicated to producing higher octane aviation fuels? RW, the introduction of 100 octane for the RAF made a big difference during the Battle of Britain. So, what if similar fuels had been available to the Poles in September 1939?

Someone will have to pay to DuPont to make the factory to make TEL. Not impossible, but something else does not get made? Granted, a good/long credit (perhaps by Austrian bank(s) in mid 1930s?) can perhaps have the factory (factories?) running before things get pear-shaped, like German invasion of Poland.
Mercury VIII that runs on 100 oct gained some 150 HP at lower altitudes - that is a very good increase. Polish need to sort their fighters 1st, though - parasol fighters with fixed U/C have a problem past 1935.

 

[tomo pauk]

May I suggest narrowing the focus of inline engines to Hispano-Suiza 12Y?
This would allow mounting a single 20mm auto-cannon as faster, all-metal bombers were being introduced. With barely 1,000 hp. late-1930s fighters could barely loft a single cannon. Look how successful So jets were with their HS engines built under license by Klimov. HS engines had plenty of growth potential. By 1942, Klimov VK-107B was pumping out 1,800’hp.

VK-107 was having problems in pumping out 1650 HP even in 1945; in 1942, it was not an option. Compared with HS 12Y, it was an all-new engine, not some sibling. Klimov's engines were probably the 3rd best family of Soviet engines (after the Mikulin's V12 and M-82s), and were lagging behind the German or British V12s. Even the unloved V-1710 was a better engine.

I'll agree with the HS 12Y in general for the second half of 1930s, however, since it indeed allows for a good cannon to be carried, being a V12 it should be a less draggy option than a radial engine, and it was a light engine so one can make a light fighter around it. It will be tricky to obtain Merlin or the DB 601, while V-1710 is too late.

 

[HoHun]

Hi Tomo,

(dashed lines are power, full lines are manifold pressure)

View attachment 716959

Thanks a lot, that's a set of power curves I hadn't seen before!

According to the caption, the full lines are power on the test stand at 15 °C and 760 mm [Hg ambient pressure]. As they provide a curve over altitude anyway, I'd say that their test stand could control intake pressure (and perhaps ambient pressure for the exhaust), but not intake temperature.

The dashed lines, according to the caption, show calculated power at altitude, which means that they mathematically corrected for the effects of air temperature in the atmosphere decreasing with altitude.

What's a bit odd is that they have added three extra data points with higher boost pressure - one for the Hispano-Suiza supercharger and two for the Szydlovski-Planiól supercharger - that show higher boost pressures than the 885 mm Hg they were using for the test run.

Regards,

Henning (HoHun)

 

[riggerrob]

Turbomeca's S/C was the best part of the HS-12Y-45 (and -49), but these were just being introduced on the D.520s. The MS 405/406 were powered by the -31 engines with the old, legacy S/C made by the parent company (HS). Difference was big, talk ~200 HP more for the -45; power surplus was at all altitudes. The -45s S/C construction that employed variable guide vanes enabled it to have the power surplus also on the low altitudes (1-speed S/Cs that offer better hi-alt power usually sacrifice the low-altitude power).
(dashed lines are power, full lines are manifold pressure)

View attachment 716959

H-S have had the -51 in the works, with crankshaft with ballances in order to turn extra 100 rpm, but it was a lo-ish altitude engine that made it's 1000 HP at some 3000 meters IIRC. Mating the -51 with the Turbomeca S/C would've provided a very good engine for the needs of 1940, if not for 1941, but even the -51 was too late in production to matter.




HS 404 was too late, even the French were still using the licence-manufactured cannons of Oerlikon design in 1940. Supplying the 404s to the E. European conutries was nigh impossible.
Oerlikon cannons were the best 20mm cannons in the world before 1939-ish, and were still very usable in any ww2 year - calling them indifferent is selling them short.

It took Klimov until 1941 to sort-out the HS 12Y, that included opting for smaller bore so the block is stronger, introduction of a 2-speed S/C, introduction of new valve train with 3 valves per cylinder.



Someone will have to pay to DuPont to make the factory to make TEL. Not impossible, but something else does not get made? Granted, a good/long credit (perhaps by Austrian bank(s) in mid 1930s?) can perhaps have the factory (factories?) running before things get pear-shaped, like German invasion ….

What if a disgruntled DuPont chemist quits and returns to his native Poland to adapt a Polish refinery to produce TEL?
Since this project is un-licensed, it is done on the quiet with little paperwork and only one Polish Air Force general in on the secret.

 

[riggerrob]

Polish need to sort their fighters 1st, though - parasol fighters with fixed U/C have a problem past 1935.

In an alternate time-line how would PZL “evolve” their gull-winged fighters to “Luftwaffe-killers?”
How many steps in the evolutionary process?
Would they try out Loening/Grumman style retractable landing gear?
Would they try to built cantilever (strut-less) high-wings?
Would they try mid-mounted cantilever wings (Brewster Buffalo or Grumman Wildcat)?
Would they hire an ex-Grumman engineer?
Would they go all the way to I.A.R. 80 style cantilever low-wings?

 

[tomo pauk]

In an alternate time-line how would PZL “evolve” their gull-winged fighters to “Luftwaffe-killers?”
How many steps in the evolutionary process?
Would they try out Loening/Grumman style retractable landing gear?
Would they try to built cantilever (strut-less) high-wings?
Would they try mid-mounted cantilever wings (Brewster Buffalo or Grumman Wildcat)?
Would they hire an ex-Grumman engineer?
Would they go all the way to I.A.R. 80 style cantilever low-wings?

Stay miles away from Grumman and Brewster, unless you want draggy aircraft.

Take a good, hard look on the I-16.
Polish have had cantilever monoplane prototype (that of the P.23 light bomber) taking flight in early 1934.
An I-16-lookalike, but with a Mercury VIII (engine used on Blenheim I, Gladiator, and the P.11-G) in the nose and with a closed canopy gives them Gloster F.5/34 equivalent - a 500+ km/h fighter by the late 1930s.

 

[Apophenia]

... Someone will have to pay to DuPont to make the factory to make TEL...

Was Dupont's tetraethyl lead bought for Royal Dutch Shell's Pladju refinery's 100 octane production?

 

[Apophenia]

In an alternate time-line how would PZL “evolve” their gull-winged fighters to “Luftwaffe-killers?”
[...]
Would they go all the way to I.A.R. 80 style cantilever low-wings?

Yes, none of the other options was going to quickly produce your "Luftwaffe-killers".

In my what-if modernisation scheme, PZL would introduce a 'new' PZL.41 Krogulec (Sparrowhawk) low-winged monoplane fighter based upon the P.11 fuselage and empennage. The P.41a would be produced on PZL's P.24 line. The P.41c would be a conversion of damaged/worn P.11c airframes.

Thereafter, a game of engine-swap musical chairs begins. The remaining P.11c airframes would get 'least-mod' conversions to P.11g Kobuz (Hobby) standards with 840 hp Mercury VIIIs. Engines removed for the Kobuz conversions would be transferred to rebuilt P.11a and P.7a airframes. The 20 x P.11a upgrades also receive wing-sets from the P.41c conversions - becoming P.11a/M fighter-bombers. Other Mercury VI S2s go to re-engining P.7a fighters to produce P.7a/M2 fighter-bombers. Any unmodified P.7a/T (Trener) for the flight schools.

 

[Apophenia]

In an alternate time-line how would PZL “evolve” their gull-winged fighters to “Luftwaffe-killers?”
[...]
Would they try out Loening/Grumman style retractable landing gear? ...

My guess that there would be little performance gain with that "Loening/Grumman style retractable landing gear". But, FWIW, I did play with the idea on Beyond the Sprues as an imagined connection forged between Jakimiuk's team at PZL and Curtiss Aeroplane.

The result was my 'PZL P.21' series with F11C Goshawk-style undercarriage options - cantilever main gear legs with spatted wheels and a fully retractable gear. But I doubt that either option would provide sufficient advantage over the P.11c to warrant production.

 

[Apophenia]

[...] Take a good, hard look on the I-16.
Polish have had cantilever monoplane prototype (that of the P.23 light bomber) taking flight in early 1934.
An I-16-lookalike, but with a Mercury VIII (engine used on Blenheim I, Gladiator, and the P.11-G) in the nose and with a closed canopy gives them Gloster F.5/34 equivalent - a 500+ km/h fighter by the late 1930s.

I'm not sure how a Polikarpov lookalike - or Gloster F.5/34 analogue - would help. The P.11 series already had more sophisticated construction than that Soviet fighter. And, if you're suggesting PZL construction techniques for an I-16 clone, I doubt that would save any time over developing the RW Mercury VIII-powered PZL-50.

 

[tomo pauk]

I'm not sure how a Polikarpov lookalike - or Gloster F.5/34 analogue - would help. The P.11 series already had more sophisticated construction than that Soviet fighter. And, if you're suggesting PZL construction techniques for an I-16 clone, I doubt that would save any time over developing the RW Mercury VIII-powered PZL-50.

It is not about the production techiniques, but about a layout. I-16 was with a cantilever low-set wing, and with a fully retractable U/C, those features cut the drag and made the aircraft go faster.
PZL-50 was a too little, too late - Polish need to make fighter with a low-set cantilever wing and the retractable U/C ASAP, talk instead of P.24, and make as many of these for themselves.

 

[Apophenia]

It is not about the production techiniques, but about a layout. I-16 was with a cantilever low-set wing, and with a fully retractable U/C, those features cut the drag and made the aircraft go faster.
PZL-50 was a too little, too late - Polish need to make fighter with a low-set cantilever wing and the retractable U/C ASAP, talk instead of P.24, and make as many of these for themselves.

Agreed that incremental developments like the P.24 were a waste of time and Polish production facilities. An example of Wsiewołod Jakimiuk being assign too many half-thought-through projects rather than focusing on immediate need. (Had I been Piłsudski's successor, every other Polish aircraft project would be sacrificed to create a plausible fighter/interceptor for 1939.)

As for "make fighter with a low-set cantilever wing and the retractable U/C ASAP", I see no faster way of Poland doing that than adapting a fuselage which is already in production. We know that the Puławski-descended fuselage was suitable to such conversion because IAR did it in the RW.

Expanding slightly on my previous comment: Creating an all-original design - regardless of whether it riffs on the I-16 layout or not - would save little or no time over developing Jakimiuk's Mercury VIII-powered PZL-50.

 

[tomo pauk]

As for "make fighter with a low-set cantilever wing and the retractable U/C ASAP", I see no faster way of Poland doing that than adapting a fuselage which is already in production. We know that the Puławski-descended fuselage was suitable to such conversion because IAR did it in the RW.

Expanding slightly on my previous comment: Creating an all-original design - regardless of whether it riffs on the I-16 layout or not - would save little or no time over developing Jakimiuk's Mercury VIII-powered PZL-50.

Oh, I have no problems with the idea that a new fighter uses the legacy fighters as part donors. Even the outer wing panels should do. Just make the darned fighter ASAP, and start rolling them out from the factory (factories?).

 

[tomo pauk]

Italy has a big-mounted neighbor in Germany once these annex Austria. Let's say Benny the Moose sees that as encroachment in the Italian sphere of influence (he was not very happy with the Anschluss when it happened, IIRC - who knows, maybe Germany will want Sudtirol now??), so he decides to lessen the spending in Spain and improve on securing the Italian airspace. Moose should be aware of German aircraft and production of the same, even if he has no exact and specific numbers.

Italian fighters - 1st and foremost, start making exclusively monoplanes with retractable U/C. 2nd - adopting the designs better suited for series production is needed, Italy was making aircraft in dribs and drabs. More focus on V12 engines, like those of what Isota-Fraschini was making (the L.121 was good for 900 HP at 4 km, the L.122 was supposed to make extra 1000). Even the legacy Asso XI is a better choice than the Fiat A.74.

Bombers/attackers - a good, hard look on the DH Comet might've helped... Note that bombs are also very good in killing ships.

 

[Apophenia]

... Even the legacy Asso XI is a better choice than the Fiat A.74...

I'm curious, in what way was the Isotta Fraschini Asso XI superior to Fiat's A.74? The former was heavier (even before accounting for radiators and coolant) and produced 100 hp less at altitude (835 hp @ 2,250 rpm versus 947 hp @ 2520 rpm for the Fiat).

The L.121 was really just a warmed-over Asso XI and the L.122 its inverted kin (addressing a new RA fixation).

BTW, it was primarily Regia Aeronautica fighter pilots who insisted upon obsolete open-cockpit biplanes.

The problems with Italian aircraft requirements were by-products of Fascist corporate policies (or lack thereof) and an overly-conservative DGCA - which reflected an unimaginative RA and a stodgy Ministero dell'Aviazione. And that is a lot of bureaucratic 'over-burden' to shift!

 

[tomo pauk]

I'm curious, in what way was the Isotta Fraschini Asso XI superior to Fiat's A.74? The former was heavier (even before accounting for radiators and coolant) and produced 100 hp less at altitude (835 hp @ 2,250 rpm versus 947 hp @ 2520 rpm for the Fiat).

'Better chioce' was my wording
It was a V12 engine, so even with drag of the cooling system it will be less of a draggy option. Fiat radials, especially as installed on the MC.200 or G.50, were also not as smoothly streamlined as it was objectively possible, with gaps between the cowling and fuselage and 'helmets' around the cowling. Usage of exhaust thrust was negligible when compared with what was done on the V12s of the day (exhaust thrust at ~5 km was adding another 10-15 km/h to the top speed, if installation was at least decent, as in case of Spitfire or D.520 for example).

Asso XI RC 40 was making 835 CV at 4 km ('nominal' rating, 2250 rpm; max rpm was 2400), the A.74 did 960 CV at 3000 m (emergency power), and 840 CV at 3800m.

The L.121 was really just a warmed-over Asso XI and the L.122 its inverted kin (addressing a new RA fixation).

I will not claim that these engines were the next best thing after the sliced bread, but can help the Italians to split the difference between them and Germany in engine power on the most-produced fighters. A MC.200 or the G.50 with the L.121 in the nose and the closed canopy should be no worse than the VG.33, Avia B.135 or the D.520, all 3 of whom were in the ballpark with Bf 109E speed-wise, and much faster than the Hurricane I.

BTW, it was primarily Regia Aeronautica fighter pilots who insisted upon obsolete open-cockpit biplanes.

The problems with Italian aircraft requirements were by-products of Fascist corporate policies (or lack thereof) and an overly-conservative DGCA - which reflected an unimaginative RA and a stodgy Ministero dell'Aviazione. And that is a lot of bureaucratic 'over-burden' to shift!

Pilots should be taking orders, not issuing them
We can recall that Italy was one of the 1st countries that went with cantilever monoplanes, capturing a lot of records with them, and also making 2-stage supercharged engines for altitude records (same as with Bristol, Junkers or Farman). But they were slow to adopt the idea of monoplane fighter with a closed cockpit and retractable U/C.
The forced switch from liquid cooled engines to the radial types cancelled almost all of the institutional knowledge gained during the development of the liquid cooled types, forcing the Italian aero engines companies like Fiat and I-F to start over from the backward positions.
We can just imagine the consequences of the British Air Ministry forcing the RR to start making radials some time in 1933-34.

 

[tomo pauk]

Re. small fighters on modest engine power - here is how the SAI 207 was supposed to perform: 575 km/h at 5500m, with 750 HP. Fighter was size of Yak-3.
Just how the Italians managed to gain extra 1500 m in the ram (dynamic) rated height vs. the non-ram (static) rated height is anyone's guess. But anyway:



Fighter was made with a lot of wooden elements, and was supposed to be produced fast, much faster than the 'normal' Italian fighters that were notoriously taxing on manhours required.

(BTW, the ~650 km/h figure for the SAI 403 is as fake as a 3 dollar bill)

French can also play this game, their HS 12X was a small and light engine with 690 HP at altitude (granted, the 12Y were also reasonably light engines). British can also do this with RR Kestrel; of course, no biplanes.
Even the Germans can do it, with He 100 as the basis (but without the surface cooling hoopla).

 

[HoHun]

Hi Tomo,

Just how the Italians managed to gain extra 1500 m in the ram (dynamic) rated height vs. the non-ram (static) rated height is anyone's guess.

They assumed a ram efficiency of 76%, a high, but not impossible value.

Regards,

Henning (HoHun)

 

[riggerrob]

If you want to see light-fighters that made it as far as the drawing board, read Justo Miranda’s book “Enemy at the Gates - Panic Fighters of World War 2.”

In an alternative-history thread, I proposed that Canadian Car and Foundry build an alternative version of Grumman’s F4F Wildcat with a 20mm auto-cannon firing through the prop hub of a Wright R-1820 radial engine.

 

[tomo pauk]

French attempt on a small, but high-performing fighter was the D.551 - roughly, it was a smaller and lighter D.520, with a bit more HP at lower altitudes, and was supposed to be much faster, as well as to climb better. Size-wise, it was right there with the Yak-3, He 100 or the SAI 207 and 403. But, like a lot of French stuff, it was too late, even if it could be argues that, at least the airframe, it was a possibility many months before the ww2.

The earlier Potez 230 was/is also interesting, being very small (smaller than the record-making He 100s with the small wing), powered by a 670 HP HS 12X engine.
Dewoitine's D.550 racer was in-between the D.551 and Potez 230, it would've been doing okay with the smaller and lighter HS 12X.
Both of the two were - you have guessed it - too late to matter, but show that there is more than one way to skin a cat.

 

[uk 75]

The problem with looking back is that we choose the successful designs and suggest the bad ones should not have been built.
The Fairey Battle is a case in point. Anyone seeing the disastrous fate of the RAF Battles in 1940 would be keen to build something else instead. But during the build up of RAF bomber squadrons the Battle helped introduce them to modern monoplanes.
It is worth remembering that if the RAF had gone to war over the Rhineland in 1936 its main bomber would have been the Vickers Virginia..
So in weeding out aircraft programmes you have to develop a method for picking winners.

 

[tomo pauk]

The problem with looking back is that we choose the successful designs and suggest the bad ones should not have been built.

We can certainly suggest the designs that were not proceeded with.
Granted, a whole heap of designs was either conceived on false assumptions (like the Defiant, Potez 63 series, Battle, biplane fighters designed past 1935 like the Gladiator or CR.42; PZL 24), or the company simply botched up (as in the case of Ba.88 and the Botha; MS.406 and Block fighters were no great shakes either, but at least these were service-worthy).

 

[Apophenia]

The Fairey Battle is what you get when officialdom tries to spec a more capable Hart/Hind replacement.

The Bristol Blenheim I is what you can get when industry provides its own ideas outside of requirements.

Simultaneous production of both Battle and Blenheim I is what you get when AM/MAP are incapable of making a useful role distinction between the two.

Personally, I'd rather see the Fairey contract cancelled in favour of Merlin-powered Blenheims. But I doubt it would make much difference whether it was RAF Battles or 'Merlin-Blenheims over Sedan.

 

[Scott Kenny]

Everybody and his brother were trying to have as good as aiforce/air-service as possible, and especially in the specified time frame, but many times the available budget was a serious brick wall between the desires and reality. What kind of aircraft should a not-rich, but a reasonably developed country (like Czechoslovakia, Poland, Sweden, Belgium, Yugoslavia, Romania, even Italy) try to purchase? Even if it means combining foreign bits & pieces with home-grown stuff? Wanted are cheap & cheerful, yet capable fighters and bombers. No biplanes, not even the strutted monoplanes - save the money on other places.
'Make' the engines you want, but something that is plausible for the time frame. Don't go awry with numbers of cylinders on the engine, like 16, 18 or 24, that will make the engine purchase expensive.
Note that there is a lot of outdated biplanes/strutted monoplanes in need of replacement, so having the affordable designs in the backburner is not out of the place for France, UK, Japan or Soviet Union. Americans can pay for turbochargers, so keep that in mind.

Note that not the budget is tight, but also the schedule - we never know when an big-mouthed neighbuor might decide to act upon the big words.

A pretty significant point is just how much technology advanced between 1935 and 1945.

You're probably going to end up with 2, maybe even 3 generations of aircraft flying, just from the amount of structural and aerodynamic improvements made in that time.

1935 or so, the Me109 is your high end example, also Hurricanes and Spitfires. The US was flying F3F biplanes and P-26 Peashooters in 1935!

I think your best bet is something akin to an early Bf109 for the 1930s, and then something broadly comparable to an Fw190 after 1940. If you're unlucky you might get a third generation in ~1943; broadly comparable to a Mustang or Thunderbolt because war were declared(tm).

 

[tomo pauk]

A pretty significant point is just how much technology advanced between 1935 and 1945.

You're probably going to end up with 2, maybe even 3 generations of aircraft flying, just from the amount of structural and aerodynamic improvements made in that time.

Agreed.

1935 or so, the Me109 is your high end example, also Hurricanes and Spitfires. The US was flying F3F biplanes and P-26 Peashooters in 1935!

I think your best bet is something akin to an early Bf109 for the 1930s, and then something broadly comparable to an Fw190 after 1940. If you're unlucky you might get a third generation in ~1943; broadly comparable to a Mustang or Thunderbolt because war were declared(tm).

Yes, the Bf 109 is/was probably the best bet among the historical A/C from the mid-1930s - easy to manufacture, small and light enough so it can perform even with legacy engines.
Both the Fw 190 and P-51 do look very good as follow-up designs, again not complicated to manufacture, and will perform well with yesterday's engines.

 

[royabulgaf]

In the US, the Peashooters were being phased out. The Spitfire did not fly until 1936, and the Hurricane and 109 had their first flights in 1935. The A5M of the IJN was easily the most advanced naval fighter, but the F3F was only slightly slower and since it was a biplane I would guess more maneuverable. You don't want to know what the FAA was flying in 1935, but I'll tell you anyway: Nimrods and Ospreys.