Fairey wins a Battle

[pdf27]

This is a one-shot based on something I was reading about today which woke up the plot bunnies.

July 1935 - Richard Fairey is growing increasingly frustrated with the Air Ministry as his attempts to get them to consider a twin-engined aircraft for the P.27/32 requirement are being stymied. Finally, he loses patience and instructs his staff to start work on a new version of the aircraft as a private venture. This is to re-use nearly everything from the existing aircraft with the exception of new inner wing sections with radiators in the leading edge.

October 1935 - upon receipt of the F.37/35 specification, Fairey orders work on the twin engined version of the P.27/32 aircraft to be accelerated. He also instructs his design team to work on a cut down fuselage design with accommodation for a single pilot and room for a pair of 37mm COW guns under the floor.

March 1936 - First flight of the single engined P.27/32 aircraft is carried out at Hayes, with the aircraft then being transferred to Martlesham Heath for trials.

April 1936 - Having achieved a speed of 257mph in trials at Martlesham Heath, the P.27/32 aircraft is formally named the Battle.

May 1936 - Design conference for the P.27/32 aircraft is held at the Air Ministry. The Supermarine Type 313 and Boulton Paul P.88 are favoured by the RAE, while the Air Ministry are strongly in favour of the Fairey design. In the end scheduling considerations win out - Supermarine are unable to fly a prototype for at least 2 years, while Fairey are nearly ready to fly and reports of the single engined design test flights are favourable.

June 1936 - First flight of the twin engine Battle, which goes on to achieve 325mph in level flight later in the month. While slightly less than the 330mph specified, both Fairey and the Air Ministry are relaxed about this since the aircraft still has the standard bomber fuselage.

November 1936 - First flight of the modified twin engine Battle takes place, with the aircraft exceeding 345mph in level flight and coming within a whisker of setting a new world speed record for landplanes while ballasted to represent a full military load.

December 1936 - The Air Ministry place an order for 150 of the Fairey twin-engine Battle design, giving it the name Falcon.

March 1937 - The Falcon design is modified to take a pair of Vickers S guns instead of the obsolescent COW guns. This weapon is essentially a bored out COW gun modified to use the belt feed of the naval Pom-Pom gun and with an improved rate of fire, giving a throw rate of up to 600 lbs/min.

June 1937 - The first production Battle enters service with No.63 Squadron at RAF Upwood.

January 1938 - The first production Falcon enters service with No.25 Squadron at RAF Hawkinge.

April 1937 - A modified Falcon using racing fuel (the same Benzole/Methanol/Acetone mix used in the Schneider trophy winning aircraft) and +18 PSI boost tries to take back the world speed record from the Germans. With each engine producing 1850 HP, the aircraft just fails to retake the record when it achieves an average of 371mph.
However, the rapid increase in drag at high speed prompts Fairey to take a second look at the wing design - the 2ft thick chord where the outer wing joins the nacelle is a legacy of the need for wing bomb cells on the Battle wing (re-used for ease of production), and is clearly limiting the performance potential of the design, and the span is probably excessive too.

November 1937 - First flight of the thin-wing Falcon. No changes have been made inboard of the engines, but the new outer wing panels are much smaller. Wingspan is reduced back to the original 54ft of the Battle. with the thickness to chord ratio reduced to a maximum 12% in the outer sections. The aircraft is now capable of 370mph on standard 87 Octane fuel.

December 1937 - The Air Ministry place an order for all Falcon aircraft delivered so far to be refitted with the new outer wings, and for all new build aircraft to be built to the same standard.

September 1938 - With increased demand for Merlin engines, a tenth factory (Ford Trafford Park) is added to the Shadow Factory scheme.

February 1939 - The British Government commits four regular army Divisions to the French in the event of war with Germany. The Falcon squadrons are included in this, being committed to the Air Component of the BEF.

April 1939 - After Fairey have tested an external bomb rack for the Falcon capable of carrying 2 x 500lb bombs under the fuselage and with the original mission clearly obsolete, the Air Ministry converts all remaining Battle orders to ones for the Falcon.

March 1940 - The first Merlin engines start being delivered from the Ford shadow factory at Trafford Park.

10th May 1940 - British Air Forces in France Order of Battle:

• Air Component
  • 5 Squadrons Westland Lysander
  • 2 Squadrons Bristol Blenheim
  • 4 Squadrons Hawker Hurricane
  • 4 Squadrons Fairey Falcon (2 fighter, 2 light bomber)
• Advanced Air Striking Force
  • 6 Squadrons Fairey Battle
  • 4 Squadrons Bristol Blenheim
  • 2 Squadrons Hawker Hurricane

14th May 1940 - An all-out attack by the RAF on the German pontoon bridges at Sedan is partially successful, albeit at heavy cost. Out of 85 aircraft attacking, 43 (35 of them Battles) are lost. Two bridges are destroyed, both by gunfire from Falcon aircraft from No.12 Squadron.

Compared to OTL the big difference is that the RAF have a handful of effective attack aircraft capable of destroying pontoon bridges with gunfire (far more accurate and survivable than bombs) - this slows down the Battle of France and means that the Germans have to fight hard for another week or two. I can't face trying to write the modifications to the Battle of Britain, but don't expect much - an Me-110 analogue isn't going to make all that much of a difference to the OTL battle.

 

[Peg Leg Pom]

I can't face trying to write the modifications to the Battle of Britain, but don't expect much - an Me-110 analogue isn't going to make all that much of a difference to the OTL battle.

It would outside of 11 Group.

 

[LoftonHenderson]

Does a Merlin-equipped Twin Battle negate the need for the Blenheim/Beaufort/Botha/Beaufighter development track entirely? Is there anything else it would butterfly away? It could definitely become the backbone of Coastal Command maritime patrol in the early war.

And could a better Battle lead to a Sea Battle in TTL? What would the effects of that be?

 

[Peg Leg Pom]

It certainly kills the Beaufighter, which was a lash up designed in a rush to provide the RAF with a Heavy Fighter. The Twin Battle is purpose designed, faster and more heavily armed. The Beaufighter just isn't needed.

 

[pdf27]

It would outside of 11 Group.

Maybe a bit, but outside of 11 Group the RAF was never really seriously challenged. Remember also there aren't very many aircraft available - probably 2-3 Squadrons worth by the summer. At this point it's still an earlier Whirlwind, the light attack role is mostly because they've started to realise the Battle is an underpowered death-trap with too little bomb load to do anything else.

Does a Merlin-equipped Twin Battle negate the need for the Blenheim/Beaufort/Botha/Beaufighter development track entirely? Is there anything else it would butterfly away? It could definitely become the backbone of Coastal Command maritime patrol in the early war.

One thing to remember is that all but the first development aircraft have the new single-seat fuselage. Range is decent but it's a bit early for them to adopt a single crew aircraft for long range work over the sea.

• Blenheim is a mature aircraft by this point - really wouldn't expect much deviation from OTL.
• Beaufort and Botha are to the same specification, a year behind the Falcon. It's hard to see them not being ordered as OTL, particularly as they have a very different role.
• Beaufighter is interesting however. As a heavy fighter it's not quite good enough, but as ground or torpedo attack aircraft it's very promising. The Falcon can just about carry bombs and it's main ground attack weapon are it's cannon - with the lack of a second crewmember being crippling for long missions. However, it's good enough that Fairey are going to be told to concentrate on building it and improving the performance. That leaves much the same niche for the Beaufighter as OTL, albeit probably with a different name - and as a Beaufort derivative most of the work has already been done.

And could a better Battle lead to a Sea Battle in TTL? What would the effects of that be?

Very unlikely IMHO. It took them a long time to get twin engined aircraft landing safely on carriers, and the Battle itself is both a big aircraft and really doesn't offer anything the navy want.

It certainly kills the Beaufighter, which was a lash up designed in a rush to provide the RAF with a Heavy Fighter. The Twin Battle is purpose designed, faster and more heavily armed. The Beaufighter just isn't needed.

See above. The particular requirement that spawned it in OTL is gone, but the ecological niche is very much till there and as a Beaufort derivative most of the work has already been done.

 

[Karelian]

Does the delay at Sedan mean that the Germans bag a lot less divisions in their race to the Sea?

 

[pdf27]

Does the delay at Sedan mean that the Germans bag a lot less divisions in their race to the Sea?

Maybe? My thinking is that the net result is that the Germans have to fight a bit harder and longer, but that otherwise the BEF gets back more or less as OTL (couldn't go much better) and the Germans still win albeit at higher cost. It's pretty clear that the Germans are going to win at Sedan, so taking down a couple of pontoon bridges only gives the defences a bit of a breather and lets them fight a little more effectively.

 

[Nell_Lucifer]

If the Falcon, a twin engine attack aircraft could do 370 mph on 87 octane in 1937 than the Germans are going to be extremely concerned as they will rightfully conclude it could reach 400 mph on 100 octane.

A butterfly might be the introduction of the FW 187 with DB601 engines instead of the Jumo 210s as a response.

 

[naraic]

Maybe a bit, but outside of 11 Group the RAF was never really seriously challenged. Remember also there aren't very many aircraft available - probably 2-3 Squadrons worth by the summer. At this point it's still an earlier Whirlwind, the light attack role is mostly because they've started to realise the Battle is an underpowered death-trap with too little bomb load to do anything else.

A number of heavy fighter squadrons attached to 10 or 12 group could actually make the big wing (as a reinforcement tactic outside of 11 group) more viable. It would have the fuel endurance to spend time forming up, fly into 11 group area and still fight.

That said the big wing would retain its historical problems that if poor coordination would see it wasted.

 

[sonofpegasus]

In OTL in 1934 Dowding as head of R & D requested permission from the Air Ministry to start developing modern rocket projectiles for firing from aircraft at ground targets. He was told that rockets were the Army's toy and that they would developed what was required, off course nothing happened. ITTL Dowding does not get the "Brush Off" and ground attack rockets based on the UP rocket already in development are duly constructed and tested. One of the first aircraft to utilize this fearsome weapon is the Fairy Falcon. Attacks on the German columns and bridges meet with mixed success. However those salvos that actually hit their intended target are shown to have a devastating effect.

 

[Karelian]

Maybe? My thinking is that the net result is that the Germans have to fight a bit harder and longer, but that otherwise the BEF gets back more or less as OTL (couldn't go much better) and the Germans still win albeit at higher cost. It's pretty clear that the Germans are going to win at Sedan, so taking down a couple of pontoon bridges only gives the defences a bit of a breather and lets them fight a little more effectively.

I'm namely looking at the combat use of 1re DCR and 2e DCR, especially the former.
If either French tank division gains time to actually deploy to battle properly, the German tank losses will be substantially larger than in OTL.

 

[duckie]

Also don't forget that the main weapon of the Falcon is an pair of Vickers S-guns, and altough it the Pz I and II's would stand no chance. A better target would be all those road bound supply trucks and other stuff like artillery and trains.

 

[LoftonHenderson]

So to clarify then, the original intended role of the Falcon is not as a light bomber or really even a heavy fighter but a gun-armed attacker? And then later it gets used as a nightfighter?

Is it only a 1-man crew or does it retain the 3 of the single engine Battle?

Edit: also with all that extra HP would a Falcon payload still only be 1,000lbs? Would it not be possible to strap 2,000lbs of bombs or a torpedo to that thing?

 

[Draconis]

I'm still puzzling over how bridges can be destroyed by 37mm cannon fire. Now the two 500 pound bombs carried by these Falcons could do it.

 

[duckie]

I'm still puzzling over how bridges can be destroyed by 37mm cannon fire. Now the two 500 pound bombs carried by these Falcons could do it.

Easy, before "smart" bombs, bridges where difficult/though targets. They very small/narrow targets. A bomb has to land within a short distance of the bridge to have an effect. With guns, you can do an straffing run and walk your fire into the bridge hitting it. An ponton bridge is made up from small boats. Sink a few of those and the bridge is damaged/sunk.

 

[CaptainCalvert]

Easy, before "smart" bombs, bridges where difficult/though targets. They very small/narrow targets. A bomb has to land within a short distance of the bridge to have an effect. With guns, you can do an straffing run and walk your fire into the bridge hitting it. An ponton bridge is made up from small boats. Sink a few of those and the bridge is damaged/sunk.

There's also a potential advantage in that the guns can provide flak suppression - the bridges were defended - while the higher speed means less time on the approach and exiting. Finally, attacking at lower level splits the attention of the defence if conventional Battles are coming in higher.

A week delay seems reasonable - it's not like the bridge is being [locally] destroyed like a bomb hit might do, but more that the damage to the deck and pontoons needs repair and checking which slows down the rate you can get people and equipment across. A few more tanks and trucks in the river at an unexpected weak point won't help.

For a near full halt you'd probably be looking at fortress guns able to fire at the bridge locations, which requires other changes (eg 50 trucks, each carrying a Bofors gun and a month's worth of ammo get stuck near to the Sedan fortresses on 1st May).

 

[pdf27]

If the Falcon, a twin engine attack aircraft could do 370 mph on 87 octane in 1937 than the Germans are going to be extremely concerned as they will rightfully conclude it could reach 400 mph on 100 octane.

So the numbers are based on:

• The OTL 257mph with a single Merlin - multiplying by the cube root of 2 gets it to 325 mph. Merlin II, 880 hp at takeoff power - fuel and supercharging probably won't allow combat power of 1030hp yet.
• Fairey apparently expected 365mph from 2240 hp in the Monarch engined variant. 365/257 is 1.42, and the cube root of (2240/800) is 1.41, so the scaling law looks about right.
• The thin wing variant is quite a bit smaller and lighter, I think a 15% reduction in drag coefficient (from reduced frontal area, lower weight for less induced drag, smaller wetted area, etc.) is realistic. That gets you to 370mph ish.
• 100 Octane plus 12 PSI boost on the Merlin III gets you a total of 2620 hp - all else being equal that's 14% faster or 422 mph. In retrospect I might have been a bit optimistic with 370mph, but 400 mph on Merlin IIIs looks easily achievable.

A butterfly might be the introduction of the FW 187 with DB601 engines instead of the Jumo 210s as a response.

That's a 1 for 1 loss of Me-110s in response. Problem is, the RLM before the war thought that the -110 was more valuable despite the lower top speed than the -187. I'm not seeing what would change here.

A number of heavy fighter squadrons attached to 10 or 12 group could actually make the big wing (as a reinforcement tactic outside of 11 group) more viable. It would have the fuel endurance to spend time forming up, fly into 11 group area and still fight.

That said the big wing would retain its historical problems that if poor coordination would see it wasted.

Still got the problem of a limited number of aircraft - at this point, probably only 2-3 squadrons in the UK available. I think you're more likely to see them covering somewhere like Scotland allowing a few more Hurricanes or Spitfires to go to 11 Group. Whatever happens it's a small impact.

In OTL in 1934 Dowding as head of R & D requested permission from the Air Ministry to start developing modern rocket projectiles for firing from aircraft at ground targets. He was told that rockets were the Army's toy and that they would developed what was required, off course nothing happened. ITTL Dowding does not get the "Brush Off" and ground attack rockets based on the UP rocket already in development are duly constructed and tested. One of the first aircraft to utilize this fearsome weapon is the Fairy Falcon. Attacks on the German columns and bridges meet with mixed success. However those salvos that actually hit their intended target are shown to have a devastating effect.

I'm always wary of multiple independent PODs - they end up too much like wish-fulfilment. What I'm trying to do here is examine the impacts of a single decision, by Fairey to build a prototype of the twin engined Battle.

I'm namely looking at the combat use of 1re DCR and 2e DCR, especially the former.
If either French tank division gains time to actually deploy to battle properly, the German tank losses will be substantially larger than in OTL.

Agreed. Won't change the outcome of this campaign, but later ones will be harder for them.

Also don't forget that the main weapon of the Falcon is an pair of Vickers S-guns, and altough it the Pz I and II's would stand no chance. A better target would be all those road bound supply trucks and other stuff like artillery and trains.

Not quite the OTL gun -they're still firing HE. More effective than the OTL attempts at low level bombing with inadequate bombs however.

So to clarify then, the original intended role of the Falcon is not as a light bomber or really even a heavy fighter but a gun-armed attacker? And then later it gets used as a nightfighter?

It was originally built as part of an argument Richard Fairey was having with the Air Ministry - he thought the Battle specification needed two engines to meet it, with the single engine requirement being forced on it by British attempts at arms control treaties. Apart from actually building it, this is OTL - the undercarriage for instance is basically that of a twin design.
In 1935 the Air Ministry issued a specification (F.37/35) for a single-seat day and night fighter armed with 4 cannon and capable of 330mph. In OTL Fairey didn't submit anything, and despite Supermarine being preferred they didn't have the capability to do it in time so Westland got the job, ending up with the Whirlwind.
Here, because Fairey have a twin engined aircraft nearly ready for test flight which pretty much meets the specification they put in a bid. Because it's nearly ready to go and nothing else is, the Air Ministry decide that's what they're getting.
The (partial) shift in role is largely a recognition that the Battle is obsolescent - this was known about in OTL, but it was what they had. The "Falcon" is ~100 mph faster and hence more survivable, and being basically a Battle can carry a similar bomb load if needed. Discovering that the guns are quite effective at the role us pure serendipity.

I'm still puzzling over how bridges can be destroyed by 37mm cannon fire. Now the two 500 pound bombs carried by these Falcons could do it.

Quick note on the guns - they aren't quite the OTL Vickers S-gun:

• At the time the specification was issued, the only cannon in RAF service was the WW1 COW gun. Smaller cannon existed, but would have to be bought in from abroad - and the HS-404 was still a ground mounted system at the time. OK when you aren't going to fly for two years, but Fairey needed something now - so it got the COW gun.
• The Vickers S-gun (Vickers owned COW by this point) is basically a modernised COW gun - bored out to take the ammunition from a 2pdr Pom-Pom, and given the application I've assumed that Vickers put together a belt feed system for it. Important to note that these are the original Pom-Pom anti-aircraft shells here - that's a 900g shell with 70g of HE filling which will make a nasty mess of most soft targets.
• Note that this is a BIG gun - 150kg each and 3m long - so I've assumed that it's too much work to change it out when the HS404 becomes available (in much the same way that replacing HS404s with it never really happened).

A long burst of this (throw weight is 200 kg/min) is going to make a mess of a pontoon bridge. Anything sturdier should be fine however.

A week delay seems reasonable - it's not like the bridge is being [locally] destroyed like a bomb hit might do, but more that the damage to the deck and pontoons needs repair and checking which slows down the rate you can get people and equipment across. A few more tanks and trucks in the river at an unexpected weak point won't help.

The French are also fighting pretty hard at this point - this isn't a week's dead stop at the bridgehead while they scratch their heads trying to figure out how to fix it, it's accumulated delays from the forces over the bridge being weaker, giving the French time to get more organised, etc. etc.

 

[Peg Leg Pom]

Still got the problem of a limited number of aircraft - at this point, probably only 2-3 squadrons in the UK available. I think you're more likely to see them covering somewhere like Scotland allowing a few more Hurricanes or Spitfires to go to 11 Group. Whatever happens it's a small impact.

With a performance of around 370mph there's going to be a huge temptation to have the available aircraft make a nuisance of themselves over German airfields in Belgium and the Pas de Calais.

 

[pdf27]

With a performance of around 370mph there's going to be a huge temptation to have the available aircraft make a nuisance of themselves over German airfields in Belgium and the Pas de Calais.

Yeah, I guess. Still only going to be nuisance levels though. If they had a lot of them there's all sorts of interesting things they could do, but given that you could essentially produce 2 Spitfires instead of one of these it's hard to see them becoming available in numbers before 1941.

 

[tomo pauk]

So the numbers are based on:

• The OTL 257mph with a single Merlin - multiplying by the cube root of 2 gets it to 325 mph. Merlin II, 880 hp at takeoff power - fuel and supercharging probably won't allow combat power of 1030hp yet.
• Fairey apparently expected 365mph from 2240 hp in the Monarch engined variant. 365/257 is 1.42, and the cube root of (2240/800) is 1.41, so the scaling law looks about right.
• The thin wing variant is quite a bit smaller and lighter, I think a 15% reduction in drag coefficient (from reduced frontal area, lower weight for less induced drag, smaller wetted area, etc.) is realistic. That gets you to 370mph ish.
• 100 Octane plus 12 PSI boost on the Merlin III gets you a total of 2620 hp - all else being equal that's 14% faster or 422 mph. In retrospect I might have been a bit optimistic with 370mph, but 400 mph on Merlin IIIs looks easily achievable.

1030 HP was the power of Merlin II and III at 16250 ft, on 3000 rpm and +6.25 psi. These values are for 87 oct fuel. 100 oct fuel indeed gives 1300 HP on +12 psi, however not at 16250 ft, but at ~9000 ft. See this handy chart.
Manufacturer's expectations rarely became real-world figures, and we can see eg. Mosquito for the real-world comparison, that was barely making 370 mph in the gun-less configuration and with far better 20 series Merlins. Expecting that our brave Falcon makes even 370 mph with Merlin III requires too strong rose glasses.