Fw 187 for 1939-45

[tomo pauk]

Another might-have been.
Focke-Wulf were making a pitch towards RLM in hope for their Fw 187 V4 to be adopted in production and service. Memo from June 1938 notes that type should be very useful for escort of the bombers, with flight duration of more than 6 hours @ 375 km/h. That was possible due to sizable fuel load (2 x 245L of fuel in wing tanks, and 620L of fuel in the fuselage tank) and use of two engines of modest power and consumption - Jumo 210G, 670 PS at 3900m each. Fuel tanks were protected (I have no specific info about the type of protection actually used).
Weapon set up was 2 fixed LMGs + 1 LMG for the backseater, as well as two cannons. MG FFs with 60rd drums each, and MG 151 with a lot of ammo (up to 600 rds each (!)); granted, some time will pass until the 151 is in production.
Expected max speed was 547 km/h at 4900m ( although some 20 km/h less was attained IIRC in real tests).

Note that I don't have any firm data on the DB 601-powered Fw 187.

So - lets have RLM warmed up to the idea, and give it green light by September/October 1938. What developments can be expected (including the installation of more substantial engines, obviously), as well as what improvements should be done to the type so it can be an useful combat aircraft as the war progresses. The Allied response might be interesting.

 

[Shortround6]

and MG 151 with a lot of ammo (up to 600 rds each (!))

Well, 600 rounds of modern 20 x 82 ammo is 123kg without links (205 grams per round, mine shells would be a bit lighter) I think a few people at FW were spending a little too much time in the Beer garden at lunch. Actual need for 50 seconds of firing time is pretty slim.
DB 601 engines are the only game in town.
You can stick in more fuel but the existing fuel tanks give less than a 50% increase for DB 601s over the 109.
The MG for the rear seater is a joke.

FW-187A-0 3d model.

Hello guys. maybe someone can help me with cockpit creation. I need info about the radioman position. I have many photos early stages of this plane and 2nd crew member sits backward. Bun on final modification photo it looks like he sits frontal direction. But i dont know what in front of him. Loo...

www.arcforums.com

Photo of the rear machine gun. It seems to be a MG 81?
Trouble is in other drawings it may not point lower than 15 degrees?
effective rear defense is not good.

Doing long missions in cramped cockpits is also not good (6 engine instruments mounted on the engine nacelles.)

Some of these things can be fixed (make the cockpit 8-10 cm wider) but that increases drag.

 

[don4331]

Remove the pilot's seat and start again like Tank did with the Fw.190.

Dietmar Hermann & Peter Pertrick book compares Fw.187 (V1) with Westland Whirlwind: The Fw.187 has a gross weight within 100kg of the Whirlwind's empty weight. You don't get that light without compromising structural robustness. (There wasn't any technology advancement that allowed massive increase in strength for same weight)

Fw.187 V4 was over weight with pilot, back seater, 4 - MG17 & MG81 and full fuel. With 2 - MG17, 2 -MG-FF & MG81, it is basically same (very little ammo for cannons). * Don't know weight of 4k disintegrating links versus 2 drums, but I'll call it a wash for this discussion (its not 100s of kg). With 2 - MG17, MG151/20s with 200 rds/gun & MG81, it does add >150kg (You will need to remove >150 litres of fuel to avoid being overloaded). As S Shortround6 says, the 4 MG17, MG151/20s with 600 rds/gun & MG81, is fanciful. If you're removing fuel, you're range isn't going to be improvement on Bf.109

Replacing Ju210s with DB601 adds >150kg/side for just the engine - not including larger radiators, propellers. More powerful engines burn fuel faster - no free lunch to go faster. And there is a balance issue with adding 400kg+ ahead of balance point (Fw.187 prototype already had outer wings pulled forward to correct balance issue (opposite of Me.210's issue)
Personally, I don't have issue with gauges on cowl, didn't Me.x10s also have gauges on cowls? Tach, fuel and oil pressure gauges on hood of my drag car were never an issue to read.

 

[Shortround6]

Replacing Ju210s with DB601 adds >150kg/side for just the engine - not including larger radiators, propellers. More powerful engines burn fuel faster - no free lunch to go faster. And there is a balance issue with adding 400kg+ ahead of balance point (Fw.187 prototype already had outer wings pulled forward to correct balance issue (opposite of Me.210's issue)

Well, you can move the radiators to the rear of the wing like they did on the 109 and 110 when they got rid of the Jumo 210s. Doesn't help the weight but it does help the balance (not entirely).

Basically you have a German P-38 without turbos.
Both have 327 sq ft of wing, the P-38 has just under 2ft more wing span and is about 1.5 ft longer.
P-38 was also carrying way too much ammo.

Estimated empty equipped weight for the Fw 187C with DB 605s was 5660kg.
Basic weight for P-38E 5770kg.
Adjust as you see fit for the lighter weight DB 601s and armament. Of course the standard DB 601 engines are going to crap out altitude wise well before the P-38 engines.
The FW 187 may be a bit faster at 5-10,000ft?
P-38E has 1135 liters of internal fuel.

 

[Capt. Vick]

Wow! Didn't know any were fitted with a rear gun!

 

[tomo pauk]

Well, 600 rounds of modern 20 x 82 ammo is 123kg without links (205 grams per round, mine shells would be a bit lighter) I think a few people at FW were spending a little too much time in the Beer garden at lunch. Actual need for 50 seconds of firing time is pretty slim.
DB 601 engines are the only game in town.
You can stick in more fuel but the existing fuel tanks give less than a 50% increase for DB 601s over the 109.

Truth to be said, the normal load-out for the MG 151s (I presume they meant '151/15' in mid-1938) was supposed to be150 rd/gun, the 600 rd/gun was in overload condition.
Solution for timely cannon armament and reasonably long firing duration might've been installing two MG C/30L cannons with 100 rd magazine for each. These also fire at 900 m/s, so getting hits on a smaller aerial target will be easier job than with the MG FF. Yes, the FF fires at double the RoF and it is much lighter.

The DB 601A is the best choice.
Jumo 211 engines should also be a good fit for the 187. We are certainly bound to loose the endurance and range vs. the 210-powered version, but even 40% fuel/engine vs. the Bf 109 will mean a lot once the required combat radius requirement is much increases, eg. actions against Norway and UK.

Dietmar Hermann & Peter Pertrick book compares Fw.187 (V1) with Westland Whirlwind: The Fw.187 has a gross weight within 100kg of the Whirlwind's empty weight. You don't get that light without compromising structural robustness. (There wasn't any technology advancement that allowed massive increase in strength for same weight)

Whirlwind was armed with 4 heavy cannons and their ammo, it used much heavier engines, cooling systems and propellers - it will be much heavier than a Fw 187 unarmed prototype.
SR6 covered the balance issues.

Basically you have a German P-38 without turbos.
Both have 327 sq ft of wing, the P-38 has just under 2ft more wing span and is about 1.5 ft longer.
P-38 was also carrying way too much ammo.

Good so far.

Estimated empty equipped weight for the Fw 187C with DB 605s was 5660kg.
Basic weight for P-38E 5770kg.
Adjust as you see fit for the lighter weight DB 601s and armament. Of course the standard DB 601 engines are going to crap out altitude wise well before the P-38 engines.
The FW 187 may be a bit faster at 5-10,000ft?
P-38E has 1135 liters of internal fuel.

The P-38 (no suffix) with turboes was 1st delivered in June 1941, by what time the DB 601A is long gone as 1st line fighter's engine for LW, the 601N is 9 months old service-wise, and 601E is being delivered.
The 601N was good for ~900 HP at 20000 ft + perhaps 12-13% extra due to exhaust thrust. P-38D had 1150 HP at 20100 ft with carb and intercooler temps being overboard due to intercooler, no exhaust thrust (= no free lunch indeed). The non-turbo engine will also benefit a lot due to ram effect, the turbo engine less so, meaning for the 601N that it will be doing more than 1000 HP at 20000 ft with ram + exhaust thrust.
All in all, while the turboed V-1710 indeed have had some advantage over the non-turbo V-1710s, advantage over the better European V12s was not there (especially over the Merlin), despite the price paid in greater volume and weight of the complete powerplant.

 

[Shortround6]

As far as strength goes, I don't know if the Fw 187 was designed for DB 601 engines or not and got the Jumo 210s because of the DB engine shortage or not. First two Bf 110s got DB600 engines? then came the Jumo powered versions. Then came the 110Cs.

I was using the P-38 sort of as a Bench mark. Not a direct P-38 vs Fw 187 comparison. The Whirlwind is too small, wing is 76% of the size and fuselage is smaller than the Fw 187.

P-38 using the same size wing (different airfoil) and close to the same engines is about as good as we are going to get, Italian DB powered twins don't have lot of good data and aren't the right size either.
Unfortunatly the early P-38 data for speed tends to jump for 5,000ft to 20,000ft.

Now lets pick the missions you want it to do. Picking a performance level and then trying to find missions is bit backwards.
The Fw 187 sacrificed and bit too much for the sake of speed and that was one of the reasons the Luftwaffe could justify turning it down. The Cockpit and forward fuselage would not do some of the things they wanted it to do (like night fighter). Maybe they were wrong.
But the competition for the "new" Fw 187 is not the Bf 110. It is the Me 210 (nobody knew how much of a turkey it was in 1939).
The Fw 187 needs at least a slightly bigger cockpit area and it needs more fuel in the wing. Too much fuselage volume is taken up with the main fuel tank.

 

[tomo pauk]

As far as strength goes, I don't know if the Fw 187 was designed for DB 601 engines or not and got the Jumo 210s because of the DB engine shortage or not. First two Bf 110s got DB600 engines? then came the Jumo powered versions. Then came the 110Cs.

I was using the P-38 sort of as a Bench mark. Not a direct P-38 vs Fw 187 comparison. The Whirlwind is too small, wing is 76% of the size and fuselage is smaller than the Fw 187.

I don't think that Fw 187 was designed for the DB 600 series from the get-go.
Yes, the P-38 is a good benchmark wrt. size and weight (at least the non-turbo version) for the Fw 187 with better and heavier engines. Whirly is indeed a bit on the small size, but weight is comparable.

P-38 using the same size wing (different airfoil) and close to the same engines is about as good as we are going to get, Italian DB powered twins don't have lot of good data and aren't the right size either.
Unfortunatly the early P-38 data for speed tends to jump for 5,000ft to 20,000ft.

The most fitting Italian aircraft to compare with up-engined Fw 187 is probably the IMAM Ro.58.
Supposed to be good for ~600 km/h on two DB 601A engines. Italian Wikipedia notes the high wing loading of the Ro.58 (per Italian standards - my remark) - no wonder, the wing area was closer to the Whirlwind than to the Fw 187 or P-38, despite the heavy engines and guns' firepower aboard.

Now lets pick the missions you want it to do. Picking a performance level and then trying to find missions is bit backwards.
The Fw 187 sacrificed and bit too much for the sake of speed and that was one of the reasons the Luftwaffe could justify turning it down. The Cockpit and forward fuselage would not do some of the things they wanted it to do (like night fighter). Maybe they were wrong.

Night fighter job is asking too much of the Fw 187.
The original Fw spec, where it was pitched as a LR escort fighter is fine with me. I'll also add an all-around fighter role, suitable for air defense and not being in disadvantage when enemy 1-engined 1-seaters are around.

But the competition for the "new" Fw 187 is not the Bf 110. It is the Me 210 (nobody knew how much of a turkey it was in 1939).
The Fw 187 needs at least a slightly bigger cockpit area and it needs more fuel in the wing. Too much fuselage volume is taken up with the main fuel tank.

A quick glance on the respective sizes and weights of the 210 and 187 should give us (or them, back in 1938) a reasoning that Fw 187 will out-pace and out-climb the 210, provided the same engines are used. Drop tank(s) are a thing even before 210 materializes.

 

[Shortround6]

Maybe you can get the Luftwaffe to drop the bomb bay requirement
and/or the dive bomber requirement (but not if you actually want to sell planes to the Luftwaffe)
Maybe (or no maybe about it) you don't need the whole two remote control MG 131 barbette thing, but you may need something more than a single MG 81 with a rather limited field of fire.
So yes, you can do many of the missions with a smaller, lighter plane.
Me 210 also held about 2500 liters of fuel so.................................

 

[tomo pauk]

Maybe you can get the Luftwaffe to drop the bomb bay requirement
and/or the dive bomber requirement (but not if you actually want to sell planes to the Luftwaffe)
Maybe (or no maybe about it) you don't need the whole two remote control MG 131 barbette thing, but you may need something more than a single MG 81 with a rather limited field of fire.
So yes, you can do many of the missions with a smaller, lighter plane.
Me 210 also held about 2500 liters of fuel so.................................

Fw 187:
no bomb bay - check
no dive bombing as designed - check
no remote barbette - check
(yes, the MG 81 installation on the Fw 187 was meh, they were suggesting addition of fixed rear-firing MG 151s for the later 187s come 1942, but I don't know how that actually adds to the actual value of the A/C; two barbettes should probably be a good thing for the 187?)

1000L +2x300L for two DB 601s should suffice for 1939-41 on a small fighter like the Fw 187 was.

 

[GrauGeist]

One issue with the Fw187's design, is it's "razorback" fuselage made for a poor field of fire for the rear gunner.

The problem with adding defensive barbettes, is the additional weight imposed by the mechanisms as well as placing that weight aft of the CoG.

 

[don4331]

The empty equipped weight for the Fw 187 V1 was 2500kg; the Fw 187C s was 5660kg.
I note the 187C has 2 - MG 131s in remote control barbette (same one more/less as Me.210). Defensive guns might add weight but they help with balance issue too.
So. the DB 605s, the MG151s and MG131s have increased weight somewhere over 660kg. But Focke-Wulf has basically doubled the weight of the basic airframe.

To make a FW187C, it is less effort to lift the pilot seat out and transfer to a completely new design, because you're basically changing everything.

Messerschmitt did it in 2 steps - Bf.109B => Bf.109E swaps engines and rebalances by moving radiators; the Bf.109E =>Me.109F replaces the fuselage (largely changes to tail) and wing. There's basically nothing left of original Bf.109B in Me.109F except pilot's seat...

Drop tanks might be a thing before Me.210, but do you have foresight to include plumbing for it in design, logistics to manufacture and supply them. A lot of ideas make perfect sense when you have 1,500hp engines and 20/20 hindsight.

 

[don4331]

Also, if Focke-Wulf is putting all its efforts into redesigning/manufacturing the Fw.187, they aren't building the Fw.190.

Which is better for Germany long term?

 

[tomo pauk]

The problem with adding defensive barbettes, is the additional weight imposed by the mechanisms as well as placing that weight aft of the CoG.

Barbettes might be a thing once heavier and longer engines are installed?

The empty equipped weight for the Fw 187 V1 was 2500kg; the Fw 187C s was 5660kg.
I note the 187C has 2 - MG 131s in remote control barbette (same one more/less as Me.210). Defensive guns might add weight but they help with balance issue too.
So. the DB 605s, the MG151s and MG131s have increased weight somewhere over 660kg. But Focke-Wulf has basically doubled the weight of the basic airframe.

You are jumping from the V1 to the DB 605-powered project. I've never suggested the V1 to be the base for anything, and there are steps with a lighter engines to do 1st.
The Fw 187 V4 was at 4900 kg with normal ammo count and full fuel, 5300 with that truckload of 20mm ammo.
FWIW:

Messerschmitt did it in 2 steps - Bf.109B => Bf.109E swaps engines and rebalances by moving radiators; the Bf.109E =>Me.109F replaces the fuselage (largely changes to tail) and wing. There's basically nothing left of original Bf.109B in Me.109F except pilot's seat...

I'm okay with Bf 109B/C/D into 109E step for the Fw 187 - major engine upgrade covers the needs just fine.

Drop tanks might be a thing before Me.210, but do you have foresight to include plumbing for it in design, logistics to manufacture and supply them. A lot of ideas make perfect sense when you have 1,500hp engines and 20/20 hindsight.

Drop tanks were produced in Germany before for the needs of Hs 123 and He 51. Worked just fine with half of 1500 HP power.

Also, if Focke-Wulf is putting all its efforts into redesigning/manufacturing the Fw.187, they aren't building the Fw.190.

Says who?

 

[Shortround6]

Barbettes might be a thing once heavier and longer engines are installed?

The Germans took forever to get the Barbettes to work right (if ever?). Yes they featured in every bomber "B" and many of the He 177s and few others but mass production seems to have either very late or not at all.
Granted B-25 bottom turrets and some other allied devices seem to have notable by their short terms of service.

The British had power turrets in service in 1939, the Americans in 1940/41. The Germans in?????? real power turrets with both power traverse and power elevation.
Jumping to remote control seems to have delayed things.

 

[GrauGeist]

For their complexity, weight and lack-luster performance, the FDSL 131 turrets were really not an advantage, to be honest.

German Remote Controlled Turrets

Hello, could somebody please give me a quick run-down of German remote-controlled turrets and how they worked? I heard that they were different from the B-29 (as it had a fire-control computer of sorts) but closer to the A-26 Invader which used periscopic sites (like in German aircraft).

ww2aircraft.net

 

[tomo pauk]

Best bet seems to forget any upgrade over the backseter's LMG, or even to forget that weapon, too.

 

[Shortround6]

Best bet seems to forget any upgrade over the backseter's LMG, or even to forget that weapon, too.

Put a step in the cockpit, (drag), install a pair of MG 81s (a bit more drag), cut down the fuselage a bit (less fuel).
At least the gunner can point out the back instead of aiming up at 15 degrees
3200rpm and lot of tracer may discourage pursuers as well as 20mm guns aimed with mirrors while the pilot tries to fly forward at 350mph.

 

[GrauGeist]

I don't recall if Tank designed the 187 to have fuel cells in the wings, if so, dropping the rear fuselage may not be a bad idea *if* it doesn't compromise any significant fuel storage.

At least with a rearward MG (or zwilling MG) gunner with an improved field of fire will weigh considerably less than the barbettes. I would also imagine that any drag imposed with a dropped deck would be less than the drag (and weight) caused by the barbettes.

 

[Shortround6]

I don't recall if Tank designed the 187 to have fuel cells in the wings

He did but they were rather small. Depending on version or drawings 210 or 260 liters in each wing root which is ridiculous compared the fuel in a P-38 wing root.
Me 210 managed about 2500 liters in the wing in 6 tanks.
The 187 wasn't going to hold that much but it seems there was some room to rearrange things.