Fast bombers alternatives for 1939-40

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

They might have gone to France with the fixed pitch props but I doubt if they kept them very long. It was about 8 months from the start of the war to the start of the BoF. Everything seems to have been a mad scramble but they had been installing DH two position props at the factory in the summer of 1939 (?, they trialed one in the summer of 1938) the Hawlers had started installing at least a few Rotol props in the fall of 1939. Home defense may have had first priority.
Evidence that the DH VP was in common use by May 1940 is how one or two Hurricane pilots preferred the old fixed position propellor in France as it gave them a slight maximum speed advantage at some cost in climb. The evidence is that these were notable exceptions.
 
Ok, no data........................but
View attachment 854819
Leo 451 with guns retracted, very slippery. Now deploy the 20mm
View attachment 854835
now lower the belly gun
View attachment 854836
Granted it was a lot skinner than it was long but what happens to the 300mph speed?
You may also want to check that 3300lb bomb load. You can fit it in the bomb bays but one old book claims range of 1430 miles with 1100lbs of bombs, you can carry 3300lbs of bombs easy, you just have leave 2200lbs of fuel at home ;)
You can carry one 100, 200 or 500kg bomb in each wing (internally) and either 32x10 or 10x50kg bombs or 5x200kg +1x100kg bomb or 6x100kg bombs in the fuselage so theoretically up to 2100kg (more since bombs actually weigh more), but in practice it was usually less than one ton and per Docavia's small spec note on the LeO 451, the range of 2300 km is for 500kg of bombs. Not sure if other range/payload figures are given or available.

I do wonder if the small operational load is motivated by the exposed targets in May-June 1940 and the prioritization of speed, and whether the heavier loads would have been used if operational or strategic bombing campaigns had been eventually launched.
 
The Bloch 175/176 was also mentionned previously in this thread, it's worth noting that a US mission to the French aero engine industry got to visit the Bloch factory in Bordeaux which was making those. They claimed that the Gnome-Rhone-powered 175 reached 560 kph at 5000m, while the P&W R1830-powered 176 flew at 520 kph at 3000m. It was noted that two-speed P&Ws were on order and would notably improve the 176's performance.
 
Not sure if other range/payload figures are given or available.
William Green listed a max of 4400lbs (two 1102lb and five 441lbs) with 220 imp gal of fuel and load/s with 398 imp gal, 530im gal (two 1102lb bombs), and 712imp gal (one 1102lb bomb)
Unfortunately he also confusing things by saying "plus one 441lb or 220lb bomb in each of two wing-root bays" so are the wing root 441lb bombs in addition to the 7 bombs in the internal bay or included in the 7 bomb total?
Unfortunately the only range figure is 1430 miles while carrying a 1100lb load.
It is quite possible that the figures were constrained by the gross weight and by changing the allowable gross weight ( more power, or better tires or stronger landing gear strut or????)
a better payload to range could have been achieved for very little investment.

It is William Green so other writers may have different specs, or a manual may surface. Trading fuel for bombs was standard.
 
Thats actually any interesting thought! At what point did engineers, aerodynamicists and manufacturers start to address the issue of bombs design from the perspective of the drag induced by externally mounted munitions?

Barnes Wallis and others designing specialist bombs obviously looked at it from more than a 'chuck some fins on a tincan / spare shell' perspective - but who specified design criteria beyond dimensions and capacity? Who made late 30's bombs and what were the evolutionary criteria?
The primary users of bombs were, as you would expect, bombers by a big margin. Short and fat fits well into a bomb bay. Drag is not important for internal carriage. Also when you are dropping vast quantities ease of production is very important.
 
William Green listed a max of 4400lbs (two 1102lb and five 441lbs) with 220 imp gal of fuel and load/s with 398 imp gal, 530im gal (two 1102lb bombs), and 712imp gal (one 1102lb bomb)
Unfortunately he also confusing things by saying "plus one 441lb or 220lb bomb in each of two wing-root bays" so are the wing root 441lb bombs in addition to the 7 bombs in the internal bay or included in the 7 bomb total?
Unfortunately the only range figure is 1430 miles while carrying a 1100lb load.
It is quite possible that the figures were constrained by the gross weight and by changing the allowable gross weight ( more power, or better tires or stronger landing gear strut or????)
a better payload to range could have been achieved for very little investment.

It is William Green so other writers may have different specs, or a manual may surface. Trading fuel for bombs was standard.
Yes, the general trend for the LeO 45X series was to considerably increase the available power using either the R-2600, GR-14R or Hercules III/VI. Not sure about landing gears.

Another factor was that the fuel itself allowed a flight time of up to 7 hours, but the oil supply was only good for 5 hours (the GR-14N consumed quite a lot of oil). The French were looking at increasing the oil capacity to achieve the actual max flight time, and this is why certain aircrafts were unavailable as their oil tanks had been removed to be replaced by the new ones.
 
I am problem going to chewed out for this but..........................

Hurricane I, which is what we are talking about in 1939-40 has a few technical things wrong with it as far as light bomber or fighter bomber goes. Some could have fixed had different decisions have been made at the time/s in question. A few of them apply to the Battle also which is part of the reason for the Battles poor reputation.

There are some other reasons like poor training and/or doctrine and some of them are just ignorance. Like very few people knew how effective light AA was going to be. Germans guessed better than others but they didn't know despite Spanish war experience.
British and French rather ignored WW I experience or remembered it as too costly and there for not to be repeated. It was too costly to use as a day in/day out substitute for artillery. It was not too costly to use for several days at a time to either push and attack through or to prevent a breakthrough while reinforcements were rushed into threatened areas.

British wanted that short field performance which meant light wing loading which equaled large wings, which means more drag and a bit more structural weight. Battle and Blenheim could fly closer to 60mph than 70 or 70 plus. This made them easy to fly and land but hurt top speed. The flaps didn't offer lot of extra lift. They helped land the planes by using drag and slowing the planes down rather than having them float over the fields if they came in even a little hot. For take off the British hurt the Merlin by giving it that high altitude supercharger. High is relative in 1939-40, Merlin III peaks around 4000ft higher than HS 12Ys or early DB601s but with 87 octane fuel they had to close the throttle to keep from over-boosting the engine and the Merlin III was only good for 880hp for take-off. Which kind of sucks for trying to get even a 500lb bomb load out of small airfield with even the 260sq ft of the Hurricane.

Things the British could have done in 1939/early 1940 that do not require using more modern aerodynamics than the 1935-36 aerodynamics used by the planes (changing structure/shape is going to delay production/service use) is using constant speed props instead of two pitch. Better climb/thrust at low altitudes and less than max speed.
Battle was designed as strategic bomber with a 400 mile radius or over double what the Hurricane could do. It was also designed to fly at 15,000-20,000ft, not sea level or at 1000ft across Belgium. Had the British installed either a medium supercharger gear or a low altitude supercharger gear they could have had somewhere around 1000-1100hp for take-off or combat flying at low altitudes even on 87 octane fuel. Use of 100 octane just adds a couple of hundred HP more. Use the fuel that suits you. It can go either way in the spring/summer of 1940. Please note that were either experimental Merlin's or service engines with both types of gears at the time. Like the Merlin VIII used in the Fulmar. You do have to change production priorities and I am not going to say if that could or could not be done. But the engines either existed or calculations as to power output existed at the time.
No saying that Hooker could have/should have developed the Merlin XX even quicker.

Those are some of the problems I have with the whole Battle vs Hurricane F/B argument. The Battle was never upgraded or given much in the way of protection or extra guns (a few got a single gun firing out through the floor, effect unknown). Hurricane II fighter bombers got the Merlin XX engine with the two speed supercharger, the Rotol propellers, 100 octane fuel and 12lbs of boost, some minimal fuel tank protection and some armor and BP glass. Some really late Hurricane had several hundred pounds of armor around the radiator and cockpit floor against ground fire so comparisons to losses sustained by Battles aren't really valid. That 400hp boost the Merlin XX gave for take-off over the Merlin III in the Hurricane I
was a real game changer as far as getting loads out of crappy airfields but then a 45% increase in power will do that for you ;)

I will note that the Hurricane F/Bs were not doing well in the attacks on France in 1942 and that was the reason that the Whirlwinds were finally given bomb racks. There were only two Hurricane Fighter Bomber squadrons (there were only two fighter bomber squadrons total but that is another story) in operation crossing the channel and such was rate of supply to over seas theaters (or to Russia?) that the existing rate of attrition was going to require at least one of them to disbanded. By mounting bomb racks on the Whirlwinds Fighter command doubled their number of fighter bomber squadrons for cross channel attacks and the reduced work load meant both Hurricane squadrons could remain operational with the reduced need for replacement aircraft. RAF was trying to use small number (not even squadrons size) of fighter bombers as 'bait' for the Luftwaffe while providing several dozen or several scores of non bomb carrying escort.

I tend to like "what ifs" that are about different choices that could have been made using pretty much existing technology of it's time. Jet powered radar equipped night fighters using missiles in 1940 are well into the land of fantasy, not "what if".

Good post
 
The primary users of bombs were, as you would expect, bombers by a big margin. Short and fat fits well into a bomb bay. Drag is not important for internal carriage. Also when you are dropping vast quantities ease of production is very important.
All of that I had assumed and agree with. The question I'm pondering, is when aerodynamics started to take a more serious role in the design? Up until external carriage started to have a marked impact upon performance - as well as the cross over to when bomb sights (finally) managed to get to the point of potential accuracy to make a wobbly and less than clean carcass holding the explosive, it doesn't looked to have mattered much.

Early bombs seem to have basically been an explosive container designed to hit nose first, with not a lot of wider design nuance apart from size, fuse type, explosive filling and the hardness of that casing for penetrative purposes. But strategic bombers were possibly not the biggest users by sortie and individual target (rather than sheer load) post D-Day - or on the Russian front for most of the war.

When did saturation become less important, and precision and the survivability of the carrier start to become more important - and did this mean the aerodynamics of external carriage became more important and a design factor in and of itself? Linking back to the OP, in 1939 internal carriage would have been a fairly essential aspect of any kind of purpose designed bomber that wished to retain any kind of tenable range and speed performance (and that failed, even then!). I know the rocket carriage for the Typhoon was modified in the light of the enormous drag penalty - and a lot of work was done post war for RAF fighter bombers too. Quite a lot is written about strategic bombs as used by the heavies and how they developed along with carriage and sighting - but I've never seen any articles about the process and development, however.
 
Last edited:
A lot of early bombers (and some not so early) either didn't have bomb-bays or had bomb-bays that were designed for much smaller bombs than actually needed to be used. So they still ended up carrying bombs on the outside. Ju 88 and Ju 87 and the Soviet Pe-2 are good examples of this.
 
Yes, the general trend for the LeO 45X series was to considerably increase the available power using either the R-2600, GR-14R or Hercules III/VI. Not sure about landing gears.

A reinforced landing gear was being tested for a bigger gross weight. A development stopped by french collapse, newly started when production was resumed for Vichy, and again stopped when Germany invaded South zone. During the "Vichy period", all developments and testings were very slow owing to the lack of.... everything.
 
All of that I had assumed and agree with. The question I'm pondering, is when aerodynamics started to take a more serious role in the design? Up until external carriage started to have a marked impact upon performance - as well as the cross over to when bomb sights (finally) managed to get to the point of potential accuracy to make a wobbly and less than clean carcass holding the explosive, it doesn't looked to have mattered much.

Early bombs seem to have basically been an explosive container designed to hit nose first, with not a lot of wider design nuance apart from size, fuse type, explosive filling and the hardness of that casing for penetrative purposes. But strategic bombers were possibly not the biggest users by sortie and individual target (rather than sheer load) post D-Day - or on the Russian front for most of the war.

When did saturation become less important, and precision and the survivability of the carrier start to become more important - and did this mean the aerodynamics of external carriage became more important and a design factor in and of itself? Linking back to the OP, in 1939 internal carriage would have been a fairly essential aspect of any kind of purpose designed bomber that wished to retain any kind of tenable range and speed performance (and that failed, even then!). I know the rocket carriage for the Typhoon was modified in the light of the enormous drag penalty - and a lot of work was done post war for RAF fighter bombers too. Quite a lot is written about strategic bombs as used by the heavies and how they developed along with carriage and sighting - but I've never seen any articles about the process and development, however.
I believe the driver behind improved aerodynamics of bombs was bombing accuracy.
1763822084109.png

Unfortunately I have, as usual, taken a snapshot awhile ago without labeling where if was from. I am looking for the report it comes from.
 
British late 30s GP bombs were not bad as far as aerodynamics go.
420px-WeaponImage_G.P._Mk.IV_%28250_lb%29.png

If you consider where they came from.
s-l1200.jpg

large_000000.jpg

and where they went.
Squadron_RAAF_Lancaster_Waddington_1944_AWM_UK1771.jpg

2000lb High capacity bomb. Crappy nose shape and stabilization by hollow drum that made up the back 1/3 of the bomb assembly, no fins, no streamlining of any sort.

British and Germans knew back in WW I that short/blunt bombs did not stabilize well. But sometimes storage considerations beat ballistic concerns.
 
German WW I bombs
rs=w:600,h:300,cg:true.jpg

From the rain drop school of aerodynamics.
Germans also tried very streamlined.
rs=w:600,h:300,cg:true.jpg

Also used canted fins to make the bomb spin as it dropped.
Might work well, if the fins are built correctly and not damaged in transit.
Defective fin/s could be worse than straight fins.
Long Streamlined bombs do not have the best HE content percentage per unit of weight.
They also do not fit well in internal bomb bays. Even a Lancaster might loose one or two rows of bombs when carrying long skinny bombs.
 

Users who are viewing this thread

Back