Focke Wulf light fighter

[z42]

For the 190 suggested above by your's truly, we look at a 3500 kg aircraft, that has 1350 PS at 5.7 km (fully rated DB 605A = Oct 1943 and on; no ram) = 2.59 kg/PS.
The 190D-9 as-is was 4270-4300 kg, at 5.7 km it had 1550 HP = ~2.76 kg/HP.

Using the big and heavy Jumo 213 or DB 603 is probably going contrary to the wishes for a lightweight Fw 190, since the weight spirals up, not down.

Well, that's the Dora as-is, not a hypothetical lightweight one to compare with your 605 powered one. Sure, the Dora can't be lightened as much due to the heavier engine, but already if you save 300kg in structural weight you're on par with your 605 powered version in terms of power /weight. And it'll almost surely be faster due to more power with very similar drag.

Now, the big advantage of the 601/605 powered version is that it can be available much sooner than the versions that need to wait for the 603 or 213 to be available, by which point the LW has to a large extent ceased to exist as a significant force. But the RLM might refuse to go ahead with a bf109 alternative with the same engine. I think it was only after using a radial that Tank's fighter plans were looked on favorably by the RLM, as the DB engine supply was already spoken for. But assuming that hurdle can be overcome, might make sense to just cancel the 801 outright and have BMW run shadow factories for 601/605 production.

 

[tomo pauk]

The Mustang was probably a quantum leap ahead of any other single engine fighter in terms of the drag coefficient (see above pdf for an overview and references to primary data). To an extent you can overcome that with more hp which the late war 605's running on C3 should do, particularly at low altitude where the lack of a two stage supercharger won't hurt as much. Enough to overcome the difference in drag?

DB 605AS and D were making about the same power at altitude as the 2-stage Merlins (bar perhaps the 70 series?), due to a bigger S/C that was still just 1-stage. Problem with these engines was that they were running late, talk mid-1944 for the AS and ASM.

P-51 was certainly a leap ahead. Cd0 was exceptional, while the advantage of Fw 190 was that it was smaller, however the BMW 801 cotributed a lot to the drag and weight. Going V12 improved the overall drag of the 190 historically; going with a smaller V12 than the 213 or 603 also improves the power-to-weight ratio and reduces the drag by an additional small amount.

 

[spicmart]

The historical FW190 already had an issue with wing flexing at high G moving the lift distribution outward, thus countering the wing twist and leading to very harsh stall characteristics.

Unsure whether saving structural weight in the wing would have been wise.

At the same time, less weight means less stress in manoeuvers which might cause wing flexing.

Likewise the harsh stall followed by a spin is a vice that could be turned into a virtue as it was an evasive manoeuver no pursuing fighter could emulate.
It should be executed above 1500 m though as it took that much to recover.
Of course this could bring you in another adverse situation by drastically reducing speed.

 

[Shortround6]

Likewise the harsh stall followed by a spin is a vice that could be turned into a virtue as it was an evasive manoeuver no pursuing fighter could emulate.

Departure from controlled flight is not a good method of continuing a pursuit

 

[spicmart]

Departure from controlled flight is not a good method of continuing a pursuit

I was quoting from Axel Urbanke's Green Hearts book.

 

[marathag]

1940
Germans take the plans for the A6M, upscale around 15%. Beef up the wings a bit, Armorglass and armored seatback added and power it with the two-stage Gnome-Rhone 14R that the Germans also decide to develop. Basic externally coated self sealing fuel tanks

Two 20mm in the wing, two 13mm cowl guns.

Sort of the look of the Kawanishi N1K1 George. But is flying in late 1941

 

[GrauGeist]

So then the Germans build a great long range fighter that cannot fight in a high-energy environment.

In the end, the question must be asked:
Why does Germany need a lightweight fighter?

The Bf109D (appropiate for the timeline suggested) weighed 3,872 pounds empty.

The A6M2 weighed 3,704 pounds empty.

i keep seeing the suggestion that the Fw190's wing area be reduced. The 34 foot wingspan the "A" possessed was narrower than many types and it was a demon at low to mid altitudes, but at higher altitudes (where most of the battles would occur) would create a handicap.

 

[marathag]

o then the Germans build a great long range fighter that cannot fight in a high-energy environment.

In the end, the question must be asked:
Why does Germany need a lightweight fighter?

The Bf109D (appropiate for the timeline suggested) weighed 3,872 pounds empty.

The A6M2 weighed 3,704 pounds empty.

A6M with the thin skins had real roll issues at speed. This remake wouldn't have that issue, much as the later A6M5c that had most of the airframe and wing improvements done

Remake/homage has a boost in power, as well, using the French Engine, so doesn't interfere with other designs needing DB or BMW power.

Best thing it brings is easier to fly, with fewer vices in the air as well as the ground handling, plus able to turn _and_ roll and dive. Far better visibility, too.

Long range is a bonus, with the free add-ons of decent radio and gunsight over the original.

Weight for the inspired/not a A6M5c and not quite an N1K might be even a bit more in weight than 3700.

Would be a lot more effective than the 109 Dora, better armament, better handling.

Extra fuel gives more flight endurance, or able to run at higher power settings for a longer time in place of more cruising range.

 

[GrauGeist]

The A6M5 was introduced in 1943, far too late for this timeline.

 

[z42]

At the same time, less weight means less stress in manoeuvers which might cause wing flexing.

From what I understood of the suggestion, the idea was to reduce the size and strength of the wing commensurate with the overall reduction in weight (which would keep the existing 190 stall characteristics, but at least not make it even worse), then further shave off weight in the P-51H spirit (which would make it worse)?

Likewise the harsh stall followed by a spin is a vice that could be turned into a virtue as it was an evasive manoeuver no pursuing fighter could emulate.
It should be executed above 1500 m though as it took that much to recover.
Of course this could bring you in another adverse situation by drastically reducing speed.

Sure, as a one off desperation maneuver it might work, but from an energy management perspective it would put the 190 into an even worse position, making it an easier target for the next pass.

However, with very little warning of the stall, pilots might not dare fly the plane to the edge of the flight envelope in the first place. Particularly at low altitude if it suddenly without warning causes you to become part of the landscape.

 

[z42]

Why does Germany need a lightweight fighter?

Indeed. From what I understand the things they were lacking late in the war was competent pilots and fuel. Airframes they had plenty of. What they needed mid war was better performing planes, to allow their pilots to survive and gain experience. Lighter weight is of course desirable, as always in aviation, to enable better performance with the engines they had. But light as a goal in itself, nope.

 

[tomo pauk]

From what I understood of the suggestion, the idea was to reduce the size and strength of the wing commensurate with the overall reduction in weight (which would keep the existing 190 stall characteristics, but at least not make it even worse), then further shave off weight in the P-51H spirit (which would make it worse)?

I'm not sure that reducing the wing's strength was in the cards for the Fw 190.

1940
Germans take the plans for the A6M, upscale around 15%. Beef up the wings a bit, Armorglass and armored seatback added and power it with the two-stage Gnome-Rhone 14R that the Germans also decide to develop. Basic externally coated self sealing fuel tanks

French authors would've just loved if everyone agreed that there was a 2-stage 14R to be had, but it was probably just 1-stage supercharged; granted, the S/C seems to be a good one, and weight will certainly be under what the BMW 801 weighted (not that of a high bar to begin with ).
Shortcomings of the A6M, at least from German PoV:
- designed without the protection, unlike the Fw 190
- it is already bigger and draggier A/C than the 190; scaling it up increases bulk and drag
- beefing it up and adding features might be a less desirable thing than having a fighter that is already designed with these features, and we're now a log way from the lightweight Zero as we know it

The G&R 14R would've probably looked good on the Fw 190, though, at least due to the probably much lighter weight of that engine.

Sort of the look of the Kawanishi N1K1 George. But is flying in late 1941

George was with 2000 HP engine, and still was under-performing.

In the end, the question must be asked:
Why does Germany need a lightweight fighter?

It probably must not
Lightweight fighters tend to be good/great performers. Good/great performers are always needed. German lightweight fighters - that by 1941 were the Bf 109s - were with a host of shortcomings: outdated cockpit, tricky undercarriage, rate of roll at high speeds was not good, not well suited for increase of firepower required. It's wing was draggier than the wing of the Fw 190, despite being smaller and thinner.
A lw 190 still has a great cockpit, excellent U/C, high rate of roll, and it better suited for carrying heavy firepower without resorting to gondola cannons. It even carries more fuel (with the 115 L rear tank it might be as rangy as the Bf 109 with a drop tank).

However, the ultimate light fighter for the LW would've been a 1-engined jet fighter.

 

[spicmart]

From what I understood of the suggestion, the idea was to reduce the size and strength of the wing commensurate with the overall reduction in weight (which would keep the existing 190 stall characteristics, but at least not make it even worse), then further shave off weight in the P-51H spirit (which would make it worse)?

High speed roll manoeuvering was one of the 190's main fortes. It should not be sacrificed by reducing wing strength in relation to weight.


marathag Japanese airframes, while being very light, are quite large dimension-wise which would be detrimental to implementing good drag-values.
Speed is key in a late-war environment.

 

[tomo pauk]

Japanese airframes, while being very light, are quite large dimension-wise which would be detrimental to implementing good drag-values.

Probably the only Japanese fighter airframe that Germans might've looked more than once was the Ki-44 - the only Japanese fighter that went along the 'big engine, small airframe' logic that both MTT and Fw were actively pursuing.

Speed is key in a late-war environment.

Pretty much.

 

[spicmart]

Laminar-flow wings were thick on the Mustangs (16% at root) and P-63. Lightweight Mustangs were still with the thick profile (15%).
Note that Fw 190 had no problems in housing even the MK 108 in the thinner, outer part of the wing, and I've suggested going with the less bulky U/C for the lw 190s.

Does a laminar flow profile generate less lift than a conventional profile for the same wing, i.e. would the aircraft have a worse climb rate?
The Fw 190 had a high-lift wing profile, IIRC, which generates much lift so that wing area could be kept small.

 

[tomo pauk]

Does a laminar flow profile generate less lift than a conventional profile for the same wing, i.e. would the aircraft have a worse climb rate?

drgondog - help

 

[Shortround6]

Does a laminar flow profile generate less lift than a conventional profile for the same wing, i.e. would the aircraft have a worse climb rate?
The Fw 190 had a high-lift wing profile, IIRC, which generates much lift so that wing area could be kept small.

Yes, we need an expert, I try to stay out of guessing at things like this because I think (?) that lift coefficient changes with speed.

What we do know is that the lift goes up with the square of the speed (or at least I think it does) so you get 4 times the lift at 400mph than you do at 200mph.
Or even a plane climbing at 180mph gets 4 times the lift than it does at 90mph at take-off.

Climb itself has very little to do with lift from the wing. Climb is dependent on the surplus power you have after overcoming drag at the desired climb speed.
If your plane needs 30hp more just to fly level at 180mph that is 30hp you don't have to climb.

 

[GrauGeist]

According to Lednicer's book on airfoils, the Fw190A's 160 sq.ft. wing design had a NACA 23009 airfoil at the tip and NACA 23015.3 airfoil at the root.

 

[tomo pauk]

According to Lednicer's book on airfoils, the Fw190A's 160 sq.ft. wing design had a NACA 23009 airfoil at the tip and NACA 23015.3 airfoil at the root.

Fw 190A have had the wing area of 200 sq ft, not 160.

 

[GrauGeist]

Fw 190A have had the wing area of 200 sq ft, not 160.

Oops, I had meant to post 197 sq.ft., not 160 - I was multi-tasking (and aparently failed)