Fixing the Italian Military, 1933~1945

[tomo pauk]

True but that is problem when you take a 1920s engine and put a reduction gear on the front and supercharger on the back and keep all the old stuff inbetween.

I don't do that - Italians did it.
If the next goal is 1300+ HP (and it should be), they will need a new engine.

OK 2nd rate engine

Instead of 3rd rate engines, like whatever I-F made in the 1930s, plus the Fiat A.74.
1st rate will need to be, again, a new engine.

You have a 32.65 liter engine turning at 2350rpm (at best?) and the DB 601 is 33.9 and turning 2400rpm and 2500rpm for take-off.
M-105 engine was 35.1 liters at 2700rpm. You have the smallest displacement and the least rpm. You need really good breathing and/or a lot boost. Except that your gas is not very good.
The 4 valve heads they used may have been hot stuff in 1924 but in the 1930s?
Mixture goes just about all the way through the heads and then turns and goes down passages on the inside of the V to reach the cylinders. Not sure if this cools the mixture or heats it?
But passage size may be restricted and sharp bends do not help. Good flow is not there.

Be it as it might, seems like 900-1000 HP was extracted from the L.121 and 122.

Using expensive German style fuel injection and refined superchargers is sort of like using a lot of small Band-aids on an arterial bleed.

Italians, as well as other people, were making diesel engines in thousands. These don't work without fuel pumps and distribution to the cylinders. Compared with the cost of the aircraft, cost of the fuel injection is a rounding error. Especially when the fuel saved is calculated in, as well as the 'price' of the pilot.
I'd say that the pointing out to the price of fuel injection system on a ww2 engine is well past the selling point.
A refined S/C was what everyone was making, so again no point to make a mountain from a mole hill.

Carry on with the fuel injection and refined S/Cs on the new gen engines.

 

[TM06]

Closest thing Italy had to a proper indigenous tier 1 engine was the 16-cylinder FIAT AS.8 which was rated for 2,250 hp at 3,200 rpm. Unlike basically every other non-radial engine with more than 12 cylinders, the AS.8 actually seemed decently reliable even on 87 octane as it successfully completed its 50-hour bench tests. It was initially only designed as a record-setter engine but the secondary objective of the engine was to provide a high-powered inline for military aircraft. However it is behind the bend with only a single-stage supercharger fitted.
FIAT was ordered to turn it into an inverted engine which resulted in the woefully inadequate A.38/A.40/A.44 engines.

Not a perfect engine by any means and would probably run into some issues in combat, but It's probably the most reasonable choice Italy would have for a tier 1 engine in a reasonable time frame.

 

[Shortround6]

Closest thing Italy had to a proper indigenous tier 1 engine was the 16-cylinder FIAT AS.8 which was rated for 2,250 hp at 3,200 rpm

Yes and no, sometimes race engines can lead to service engines and sometime not.
This race engine (like many) was set up for sea level running.
From Wiki so...................
"This V-16 engine used a supercharger similar to that used on the Fiat AS.6 capable of delivering air at a boost pressure of 1,350 mmHg (53.15 inHg)."
This actually tells us very little about the supercharger. The Supercharger on the Allison C-15 engine (Tomahawk) could deliver a boost pressure in the very high 60s without ram.
It was smaller and could not deliver the volume of air needed for more than just about 1700hp.
This is actually not very good pressure for a supercharger as this is a 1.77 to one pressure ratio. The Supercharger on the Merlin III was good for about 2.5 times at 16,000ft.

Anybody worth his paper and pencil would have set the supercharger up to flow about the maximum amount of air (boost) that the engine could stand while using the least amount of power to turn the supercharger, giving the maximum efficiency with the least heating of the intake charge. Great for setting records at low altitudes but lousy for higher altitude performance.
What I don't see in these articles is what kind of fuel this engine was being run on during these tests. Anybody that was trying for a speed record was not using gasoline of any type/octane rating. All of the speed records in the 1930s were done using special fuels, often tailored for each engine and often based on methanol. I believe it was Rod Banks, the Englishman who blended the fuel for the Supermarine S.6B who also blended the fuel for the Macchi-Castodi MC.72 when they succeeded at the speed record. Germans were certianly not using gasoline in the He 110 or Me 209 record runs.

the AS.8 actually seemed decently reliable even on 87 octane as it successfully completed its 50-hour bench tests.

Which brings us to this. I would hope that a race engine when running on 87 octane was "decently reliable" as it is making a lot less power than when running on racing fuel. The thing should have been 99.9% reliable operating at about 60% of it's racing power
I have no Idea of what the 50-hour bench test is. A lot of companies may have used a 50 hour test as a bench mark in development. What that test consisted of may be entirely up to the company. International or commercial tests for certification were almost always 100 hours. Russians wanted a 100hr test on the Hispano-Suiza in 1933, it failed but that is a different story

However it is behind the bend with only a single-stage supercharger fitted.

There is no reason (or very little) to use a two stage supercharger when all you have is 87 octane fuel. The more you compress the air in the supercharger the hotter it gets and all "octane" tells you is about at what point the fuel/air mixture will auto ignite. With 100 or 100/130 you can really compress the air and not have it auto-ignite (detonate) and wreck the engine. Inter-coolers help because they lower the temperature of the air and allow for more boost to be used before you hit the limit. Water injection also helps.
2 stages worked for the Allies because they had the 100/130 fuel. The octane rating scale is not linier and 87 octane fuel is actually 68.29 on the performance number scale. 100 equals 100 on both scales. There is nothing over 100 on the octane scale.
It also turned out that flying and fighting at over 30,000ft was a lot harder than people thought and to spend any time (more than 1-2 hours) there you needed pressurized cabins for the crews and the higher you went the less time you could spend there. Record flights were dangerous stunts but they didn't know how dangerous when they did some of them.

Build a decent single stage supercharger before trying for the two stage. The two American two stage superchargers were not very good to begin with. The GE compressor in the turbos was not very good as a compressor and this was hidden by the abundant power of the turbo and the fact that GE had learned very early that they needed an intercooler to make it work at all with the fuels of the day. It was also very much a a work in progress. The P-38 went through 4 different models of turbos and GE had gone through several experimental models before that. The two stage supercharger in the P & W engines was also somewhat limited. The one in the F4F wasn't much better than the supercharger in the Merlin III. Of course just about everybody else was behind the Merlin III in 1939/40 by various amounts.

Two speed is a lot different and lot easier. But it is not really an easy way to high altitude power. What it usually was, was a way to get 15-20% more power for take-off and very low altitudes without loosing high altitude performance. Please look at the Italian engine model names, if you are not aware of it already, the last 2 numbers are the rated altitude in hundreds of meters. The Fiat A74RC38 gave peak power at 3800 meters. The Fiat A74RC42 gave peak power at 4200 meters except, it gave less power at lower altitudes. because the fast spinning impeller took more power to turn and it heated the intake charge more meaning you had thinner and hotter air and sometimes you had to use a little less boost.
US P&W R-1830 engines that were rated at 1200hp often only gave that power to 4900ft (1493 meters) after which power fell off until the supercharger was shifted and power went back up to 1050hp at 13,100ft and that is with 100 octane fuel. The Fiat A74 doesn't look quite so bad. Two speed supercharger might not have done much for it at 4000 meters but it might have been worth over 100hp for take-off

Edit.
The Fiat A.74 was not as bad as many people had assumed. It was rated at 947hp at 3000 meters at 2520rpm emergency power. The 840hp at 2400hp at 3800meters is the "normal" rating which is usually the Max continuous power. Unfortunately not all countries could agree on common terminology but most countries could agree on "normal" rating for international commerce.
US did not start using "military rating" until some time in 1940-41? Many times Military rating was the same (or very close to it) as take-off rating ( 5 minutes or less) , same RPM and same or close manifold pressure. The P&W R-1830 engines that showed right before 90/91 octane and 100octane gas but ran at 2700rpm for take-off and 2550rpm for max continuous (older ones were lighter but were limited to lower RPM) on 87 octane were good for 1050hp for take-off but were rated at 950hp at 2550rpm at 11000ft (3352 meters).

The A. 74 was about 150lbs lighter (give or take) about 25mm smaller in diameter and made about 110hp less about 450 meters higher up at max continuous. A lot closer than the usual 1100-1200hp P&W vs 840hp A.74 we are usually told.
The higher octane fuel in the single speed R-1830s that were rated for it didn't do much at 10-11,000ft but did give more power closer to sea level.

 

[z42]

As we've seen in this thread, Italy definitely faced a huge uphill struggle in quality and quantity of equipment as well as fuel when going up against the Allies. Is there some kind of asymmetric response the Italians could have done rather than trying to match Allied capabilities 1:1?

An "Italian SAS/LRDG" operating in the deserts of NA, blowing up planes on the ground?

 

[Hardrada55]

As we've seen in this thread, Italy definitely faced a huge uphill struggle in quality and quantity of equipment as well as fuel when going up against the Allies. Is there some kind of asymmetric response the Italians could have done rather than trying to match Allied capabilities 1:1?

An "Italian SAS/LRDG" operating in the deserts of NA, blowing up planes on the ground?

Like the Compagnie Auto-Avio-Sahariane?
View: https://www.youtube.com/watch?v=0Te06YWuMDw

 

[swampyankee]

As we've seen in this thread, Italy definitely faced a huge uphill struggle in quality and quantity of equipment as well as fuel when going up against the Allies. Is there some kind of asymmetric response the Italians could have done rather than trying to match Allied capabilities 1:1?

An "Italian SAS/LRDG" operating in the deserts of NA, blowing up planes on the ground?

Well, they did have Decima MAS.

 

[Airborne2001]

As we've seen in this thread, Italy definitely faced a huge uphill struggle in quality and quantity of equipment as well as fuel when going up against the Allies. Is there some kind of asymmetric response the Italians could have done rather than trying to match Allied capabilities 1:1?

An "Italian SAS/LRDG" operating in the deserts of NA, blowing up planes on the ground?

Like the Compagnie Auto-Avio-Sahariane?
View: https://www.youtube.com/watch?v=0Te06YWuMDw

Well, they did have Decima MAS.

Honestly, and excuse my language, but the main thing that needed to happen was Mussolini removing the stick up his ass and realizing that Italy needed to be willing to get non-fascist international help and try new ideas.

First, he needed to stop worrying about Balbo getting acclaim and having to possibly give the US credit for oil reserves while simultaneously realizing that oil >>>> farmland:

https://qr.ae/pCrFlF

View: https://www.youtube.com/watch?v=FxMUQEXcCso&list=LL&index=1
Pinned comment from the video:
"Sorry Tik your info are partial and half/wrong.( you have only the final part of it ) Ardito Desio following the italian victory in the italo-turkish war he start to become interested in oil research in libia, becouse he read some reports that stated: that italians troops digging for water discovered some very superficial oil, in the region of cirenaica and in the gulf of sirte. (his investigation was interrupted by ww1 and restarted in the 20's)In 1926 together with Agip (italian national oil company) wich did some preliminary search he did some digging. He was sent back again in 1929 (under Badoglio administration) and he discovered in multiple travels/years a lot of oil between 1930-1936 (funny enought he discovered it in the same spots the italians re-discover later during the period of the agip administration of Mattei (wich allegedly was killed by the french secret service for helping states like algeria and others to gain indipencence and challenging the 7 sisters "the 7 big oil companies, offering better share if they accepted his proposal but thats another history)In 1929-1936 Badoglio was the governor of Libia and he autorized the search for oil fields, so Desio traveled around usually on camel,and found many of it, unfortunately the majority where to deep to be useful, so thrue Balbo wich had many connections with usa (thx to him being famous for flyng around the globe) he tried to obtain a probe able to go that deep, but thats where the story become uncertain it seams that Mussolini interfer with it so the texan friend of Italo Balbo never sent the probe.. and Desio was forced to give up.Another thing that is sure, is that agip the italian oil company under Mattei administration used Desio charts to start their search and found that Desio was overall right. (1953-1962 period)Desio bringed home lot of "samples" in italy we talk a lot about the "bottiglione" the big bottle of oil he bring as sample around 1938. https://slideplayer.it/slide/927102/2/images/22/Ancora+in+Libia%3A+il+petrolio%21.jpgHe found also potassium salts and magnesium mines, at the end of his probing period he found no less then 18 oil fields.But overall the Fascist government where interested in libia as farming ground, if you need more help about the subject fill free to contact me i am an italian historician from university of Bologna.Sources: https://i.ibb.co/Ks4D4vh/olio.jpg "

Second, he needed to stop viewing advanced technology like radar as "communist ideas" (just like how the nazis saw nuclear science as "Jewish science") and accept that the expenditures for radar in war were worthy. Same thing with carriers (the UK feeling like it needed carriers despite its insanely expansive naval bases across the globe should've spoken volumes to Mussolini way earlier than the impact of Taranto).

Another thing was not deposing the king, which would've made all loyalty go to him instead of being split and would've allowed him to establish the dictatorships Germany and Japan had to get more war support. He could've used the discovery of oil as a way to distract from the upheaval by "lying like a politician" to say that the discovery was solely his doing.

 

[bf109xxl]

Second, he needed to stop viewing advanced technology like radar as "communist ideas"...

Interestingly, such radical anti-communism did not prevent Mussolini from selling weapons and technology to the communists (i.e., the Soviets) for nearly a decade. Just business...

 

[Airborne2001]

Interestingly, such radical anti-communism did not prevent Mussolini from selling weapons and technology to the communists (i.e., the Soviets) for nearly a decade. Just business...

This is a fair point. I will say that the radar also was seen as "too expensive".

That being said, this does also show how corrupt Mussolini could be by preaching one thing then doing the other.

 

[Zmauky]

Well, as far as I'm concerned, communists (extreme left) and fascists (extreme right) meet at the bottom of the circle. Maybe not in terms of rhetoric, but certainly in terms of corruption and incompetence of the government and violence against its own population. Besides, didn't Mussolini enter politics as a candidate for the Italian Communist Party?

 

[yulzari]

Well, as far as I'm concerned, communists (extreme left) and fascists (extreme right) meet at the bottom of the circle. Maybe not in terms of rhetoric, but certainly in terms of corruption and incompetence of the government and violence against its own population. Besides, didn't Mussolini enter politics as a candidate for the Italian Communist Party?

And at one time a paid agent of the British crown handled by Liberal Minister for Transport Hore-Belisha MP.
It was when Mussolini was running a newspaper and Britain feared Italy might drop out of the Great War so paid Mussolini to keep up a pro-war stance in its writings.

 

[Humblebee]

And at one time a paid agent of the British crown handled by Liberal Minister for Transport Hore-Belisha MP.
It was when Mussolini was running a newspaper and Britain feared Italy might drop out of the Great War so paid Mussolini to keep up a pro-war stance in its writings.

It wasn't Leslie Hore-Belisha but Samuel Hoare ( the future appeaser and Foreign Secretary etc) who paid Mussolini. Hoare was working for MI6 during WWI

 

[Airborne2001]

And at one time a paid agent of the British crown handled by Liberal Minister for Transport Hore-Belisha MP.
It was when Mussolini was running a newspaper and Britain feared Italy might drop out of the Great War so paid Mussolini to keep up a pro-war stance in its writings.

Yeah that's opportunism for you. He was far-left at first when it was convenient, but then the moment it was realized that communism might not work in Italy he switched and invented fascism based on the vittoria mutilata. His inherent opportunism and cronyism is why things like the Fiat-Ansaldo monopoly on tanks existed, and why very big things like trying to jump at France when Italy was three years away from being ready for WWII happened.

 

[yulzari]

It wasn't Leslie Hore-Belisha but Samuel Hoare ( the future appeaser and Foreign Secretary etc) who paid Mussolini. Hoare was working for MI6 during WWI

My error. Apologies. Indeed Sir Samuel Hoare was his MI5 handler.

 

[Airborne2001]

Now, back to the topic of aircraft, one aircraft that I think actually would've worked great as a ground attack aircraft is the Ba.65 if Breda didn't end production in 1939.

The aircraft actually performed very well for the 1930s. It was a ground attack aircraft that could fly at over 400kph in its strongest form and had a reasonable armament of 2x12.7mm and 2x7.7mm machine guns. Domestic variants used the 700hp Gnome-Rhone K-14 license, though export variants used the 1,000hp Fiat A.80. The Chilean ones actually had 23mm Madsens as part of the armament, though these ones did suffer from excess weight.

Really, what the aircraft needed was to fix its issue of low armor protection and having a stronger engine to handle more armor and keeping good performance with the defensive turret. Maybe give it a Fiat A.82 RC40 of 1,250hp (or the Piaggio P.XIX) to account for things like self-sealing fuel tanks and armor, and then up gun it to 4x12.7mm machine guns. The standard 500kg bomb load wasn't terrible, but a rise up to handle at least the 600kg+ Italian bombs could help, although that on top of the armor and primary weapon increase would likely require a Fiat A.82 RC42 of 1,400hp instead.

 

[Shortround6]

What Italy needed was a new airplane.
Or at least heavily modified version with a new engine and I am not talking about the Fiat A.80.

See

Breda Ba.65

The Breda Ba.65 was an Italian ground attack aircraft that first saw action during the Spanish Civil War. It was built in both single and two-seat configurations, and was exported to various nation…

plane-encyclopedia.com

For a more detailed history than Wiki.

Problem is that the Ba 64-65 series is about 1-2 years older than the Hawker Hurricane and is about the same size (wing area, wing span and weight) while trying to use a small internal bomb bay and a rear cockpit and holding more fuel. The more 'stuff' you put in to improve it the higher the weight and wing loading.
Using higher powered engines is an option but requires more work. The Fiat A.82 engine was about 300lbs heavier than the A.80 engine and you need a bigger propeller to use the extra power, even if it is just wider blades with the same diameter.
A photo of a wreck shows the construction better.

Like some other planes of it's era (mid 30s) the wing was metal covered from the leading edge to the main spar (?) and fabric covered from the main spar aft.
Yes a new version could change that. Hurricane went from all fabric covered with to all metal covered (interior structure also changed?)

Italians wanted to change. But the two replacements pretty much failed, the Breda Ba 88 spectacularly which lead to the forced use of the Ba 65. Question is if was worth any further development?

 

[MikeMeech]

Like some other planes of it's era (mid 30s) the wing was metal covered from the leading edge to the main spar (?) and fabric covered from the main spar aft.
Yes a new version could change that. Hurricane went from all fabric covered with to all metal covered (interior structure also changed?)

Italians wanted to change. But the two replacements pretty much failed, the Breda Ba 88 spectacularly which lead to the forced use of the Ba 65. Question is if was worth any further development?

Hi
Stressed skin (metal covered) wings started to replace the earlier fabric covered wings on the Hurricane on the production line during the first part of 1939. There were changes to the structure of the wing (see below), the fuselage basically remained the same.

Drawings from 'Aeronautical Engineering' Edited by R A Beaumont, published in the early 1940s.

Mike

 

[tomo pauk]

Several strong alternatives to the upgraded Ba.65:
- Ro 57 - it does use two engines (probably the only downside, considering the state of the Italian engine manufacturing), but can lug up to 1000 kg bomb; tweak bomb and fuel load for greater ranges
- bombed-up fighters - Re 2000 series is probably the best there due to it's generous wing and reasonably-powered engines; the Re-2003 was supposed to carry up to 650 kg of bombs
- Ca 355 - there is no reason that it cannot be made earlier, even accepting the lower powered engines and a lighter bomb load, as it was the case with the Ca-335

 

[Geoffrey Sinclair]

Hi
Stressed skin (metal covered) wings started to replace the earlier fabric covered wings on the Hurricane on the production line during the first part of 1939.

Second part of the year for production Hurricanes.

Putting Hurricane I changes into the one list. First order 600 L serials, second order 300 N serials, third order 1,000 P serials split 500 Gloster, 500 Hawker, with the Hawker section gaining another 24 P, R and W serials as replacements for foreign orders.
Hawker:
61st aircraft L1607 first factory fitted ventral spine (Unconfirmed), taken on charge 6 July 1938.
331st aircraft L1877 fitted with Metal wings for development, taken on charge 16 March 1939
363rd aircraft L1909 first factory fitted Merlin III, taken on charge 20 April 1939
434th aircraft L1980 first factory fitted two pitch propeller, taken on charge 12 June 1939
480th aircraft L2026, marked metal wing, Rotol propeller, development, built in July 1939, taken on charge 28 October 1939
481st and 482nd aircraft L2027, L2028 marked metal wing, both taken on charge 20 July 1939, L2027, L2028, L2039, L2045, L2046, L2047, L2055, L2058, L2065, L2066, L2067, L2068, L2077, L2078, L2079 marked metal wing (July/August 1939)
668th aircraft N2397 and subsequent fitted with TR1133, taken on charge 9 November 1939
685th aircraft N2426 marked as last aircraft of the order with fabric wings, taken on charge 14 November 1939, but see below
901st aircraft P3265 and subsequent fitted with Rotol propellers except for at least one batch meant for tropical service which retained the two pitch DH propellers, P3265 was for development, built in February 1940 but not officially taken on charge until 31 May 1940.
June/July 1940 Hurricane I built with fabric wings at Brooklands P3714 to P3717, P3737 to P3739, P3755, P3757 to P3761, P3767, P3768, P3770 to P3774, P3854, P3858 to P3869, P3872 to P3875, P3882 to P3890, P3897 to P9303, P8809, P8810, P8816 to P8818, R2680, R2681, V7200 to V7209, V7222, V7224 to V7235, V7276, V7281. Total 85 aircraft.

The Ministry of Aircraft Production Price Books indicate the 300 N serials were 35 Fabric wing, 253 metal wing, 12 sold to other customers (Yugoslavia, last 12 serials so expected to be metal wings) The metal wings cost £1,210 the fabric ones £1,008. N2426 is the 85th of the N serials batch meaning 35 out of the first 84 had fabric wings. If you go by taken on charge dates it was part of a group of 5 taken on charge 14 November 1939, the 57th to 61st N serials to do so.

A further complication is the 20 aircraft N2318 to N2337 were the first built at Langley, some had fabric wings, delivered from October 1939 to January 1940, time wise lagging behind later serial deliveries from Brooklands.

It appears from L2026 (480th aircraft) to N2426 (685th aircraft) there was probably an increasing percentage of metal wing Hurricanes built.

Gloster production started in October 1939 with Merlin III, two pitch propeller, metal wing, the 100th built, P2681 and subsequent fitted with TR1133 radio, the 101st built, P2682 and subsequent fitted with a Rotol propeller, P2681 and P2682 taken on charge 27 February 1940

Date wise production starts in December 1937 with Merlin II, fixed pitch propeller and fabric wings, Merlin III from April 1939, De Havilland two pitch from June, a mixture of fabric and metal wings July to November except a handful of possible laggards from Langley, from then on metal wings except the mid 1940 batch, mid November 1939 (Hawker) and late February 1940 (Gloster) change over to TR1133, late February 1940 change over to Rotol propeller.

Sold to Glosters for Finland: N2322, N2323, N2324, N2325 (damaged en route, returned to RAF), N2327, N2347 (crashed in Norway), N2348, N2350, N2358, N2392, N2393, N2394, N2395

Two different draft passages trying to say much the same thing on metal wings from the Hurricane Biography, AVIA 46/114.

As regards the second difficulty, that of the stressed skin all metal wing (File No. 522507/36), the prototype had fabric wings, but it had always been hoped that production aircraft would have the new stressed skin wings. In these wings the metal covering was made a part of the weight bearing aerial structure. The importance if the stressed skin lay in its weight saving capacity. Fabric covered wings had already reached the limit of weight allowed and the stressed skin wings saved no less than 70 pounds. Investigations by the firms into this question had been started as early as July 1935. When the production specification was drawn up however it was decided that the Hurricane should in the first place be fitted with fabric covered wings, which would be interchangeable with metal ones. At this stage the technical state of the stressed skin wings was still experimental and not progressed further than the design stage. The position was aggravated by the fact that Hawkers were working on two other monoplanes for the Air Ministry at the same time, the P.4/34 [Henley] and the F.9/35 [Hotspur], both of which were expected to have metal wings. The construction was the same in each case, the difference being in the armament. In June 1936 it was estimated that the test wing would be ready by September but "stiffness" problems arose which involved a new design and it was necessary to earmark a special group of men in the drawing office for metal wing development. In December it was agreed that the P.4/34 should be fitted with the first pair of metal wings. This decision naturally reacted adversely on the Hurricane and in October 1937 it was considered that the new wings could not come in before the 301st aircraft. It was not until March 1939 that the first pair of production stressed skin wings were received from Glosters and fitted to production aircraft at Brooklands. Shortly afterwards flight tests were completed and the wings were cleared for operational use.

Although the prototype had fabric covered wings it had always been hoped that production aircraft would all have the new stressed skin wings in which metal covering was made part of the weight bearing structure, but when the production specification was being drawn up after the first order, it was evident that the first place Hurricanes would have to be produced with fabric covered wings, which would be interchangeable with the metal ones. At that moment it could not be laid down exactly how many Hurricanes would have to be fitted with the fabric wings for the technical state of the stressed skin wings was still highly experimental and had not progressed further than the design stage. Hawkers were working on two other monoplanes for the Air Ministry, the P.4/34 [Henley] and the F.9/35 [Hotspur], both of which were expected to have metal wings and the question of which type should have priority was a difficult one. In June 1936 the R.T.O. had judged that the test wing would be ready by September and the first pair of wings ready for fitting to an aircraft in March. Later "stiffness" problems arose which involved a redesign to combat the delay which was inevitable it was necessary to earmark a special group of men in Hawker's Drawing Office for metal wing development and by October it was thought that the first tentative troublesome design stage was over. In December the question of priority had to be finally dealt with and the prototype P.4/34 was chosen for the fitment of the first pair of metal wings, somewhat naturally to the detriment of the Hurricane stressed skin wing development. As might be expected, this meant the definite postponement of production aircraft changing over to the new wings for some time and in October 1937 it was thought that the new wings could not come in before the 301st aircraft. In March 1939 the first pair of production stressed skin wings were received from Glosters and fitted to production aircraft at L1877 Brooklands. Shortly afterwards flight tests were completed and the wings were cleared for operational use. The fact that Glosters had been subcontracted to build the wings, however, probably increased the delay for Mr. Lemon in his famous report of September 1938 (EPM 120 (38)) complained that the production situation at the Gloster Company was quite one of the worst in the entire industry and the order for Hurricane wings was suffering as a consequence.