Questions regarding the shape of the Me 262 and Focke-Wulf 187 fuselage.

[ThePolishAviator]

The Me 262 and the FW 187 are 2 German WW2 designs that are both known for their exceptional speed and agility compared to other aircraft in their weight-class. They also share a weird quirk which is their fuselage cross-section. It's a triangle with rounded edges and walls that are somewhat curved.



I heard that such a design helps to provide lift and is easier to produce than round fuselages. also since the fuselage comes to a point at the point at which the wings are attached I figured that interference drag would be decreased.

But if it provided such advantages then we would see it in at least some post-war designs but I never managed to find such a design. Does this design have some aerodynamic drawbacks I am not aware of or are the advantages it provides too negligible to make up for the extra parasite drag?

 

[sienar]

Ludwig Bölkow designed the fuselage for the 262 and said that it was based on DVL research that showed less interference drag.

 

[OliverSedlacek]

I read that the 262 fuselage was triangular to house the main landing gear without adding more than the minimum drag.

 

[ThePolishAviator]

Ludwig Bölkow designed the fuselage for the 262 and said that it was based on DVL research that showed less interference drag.

Isn't a simple expanding radius fairing enough to reduce interference between the wing and the fuselage?

 

[Nicknick]

Alice Aviation (the first two) had a similar shape.

 

[riggerrob]

My guess is that the fuselage cross-section/bulkheads was optimized for vision downwards. compare this with how the canopy on Grumman's F8F Bearcat bulges out from the topsides of the fuselage. By leaning his head to the sides, the pilot can see better downwards and forward.

 

[Scott Kenny]

Isn't a simple expanding radius fairing enough to reduce interference between the wing and the fuselage?

If the wing meets the fuselage at a 90deg angle, that's how you get minimum drag.

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The flat panels are definitely easier to fabricate than curved sections. Plus, it looks like at least the bottom corners are a constant diameter for most of the aircraft length, which also makes fabrication easier. You set the rollers to make the right diameter and leave them there. You only have to fight with complex shapes at the very nose and tail, so you can assign your most experienced metal shapers to make those parts.

 

[Nicknick]

Not so sure about that, the triangle shape is a bit more blended wing body like than a rectangular wing. Note that the underside of the wing is almost flush with the bottom and the angle between the wing and the body is less edgy on the upper side as well.

However, I do agree that better vision played a role too, German aircraft designers put more emphasis in this for fighter planes than the Allied. One reason for the A-Design of the German inline aero engines was the improved vision, so it is logic to go even further with this attempt with a jet powered aircraft.

 

[Arjen]

German aircraft designers put more emphasis in this for fighter planes than the Allied.

Bf 109? Bubble-canopies for Whirlwinds, Typhoons, Tempests, late model Spitfires & Mustangs & Thunderbolts, Bearcats...

 

[Nicknick]

it took a while until Germany could produce bubble canopies, the Fw 190 had a bubble canopy.

 

[Scott Kenny]

it took a while until Germany could produce bubble canopies, the Fw 190 had a bubble canopy.

Not like the P-51D or Bearcat.

 

[ThePolishAviator]

However, I do agree that better vision played a role too, German aircraft designers put more emphasis in this for fighter planes than the Allied. One reason for the A-Design of the German inline aero engines was the improved vision, so it is logic to go even further with this attempt with a jet powered aircraft.

While A shaped engines do have the potential do give you better vision the Germans did not take advantage of that fact at all in their aircraft. Due to the way the prop-spinner cannon is installed the engine is mounted very high up reducing vision compared to similar V-engine designs.

One additional argument against that claim is that despite the extremely heavy changes made to the BF-109 during it's production run it never received a better canopy. It was a razorback plane even as it was modified to be almost unrecognizable from its original design. They never used thinner struts nor did they give it a good canopy. They even were willing to cripple any rear-vision by installing a very large armored plate just behind the pilots head (though to their credit in some variants it was replaced by bulletproof glass making the vision the same as before).

 

[Nicknick]

The A-engine configuration surly didn't help looking backwards and also not in looking along the symmetry axis forward. The improvement was in looking slightly downwards and sideways in frontal direction.

Here you find an intresting video on how bullet prooved glas can even enhance the vision:

View: https://www.youtube.com/watch?v=uCGsyjt5ANU&ab_channel=I%2FJG27_Nemesis