Aerodynamics of high-winged fighters.

[Thumpalumpacus]

Generally speaking, monoplane fighters of the WWII era had low-mounted wings, rather than high-mounted. I imagine that that's for keeping landing-gear closer to the ground.

But was there any aerodynamic reason to favor low- over high-mounted wings?

 

[Admiral Beez]

Generally speaking, monoplane fighters of the WWII era had low-mounted wings, rather than high-mounted. I imagine that that's for keeping landing-gear closer to the ground.

But was there any aerodynamic reason to favor low- over high-mounted wings?

I don't think I can recall any high wing single seat fighters. I assume the low wing was used to keep the main spar low, so to allow the pilot, fuel and radio to go above the spar. Here's the Spitfire, would a high wing spar location be possible?

 

[Admiral Beez]

There are parasol and gull wing fighters, like the PZL P.7.

PZL P.7 - Wikipedia

en.wikipedia.org

 

[Thumpalumpacus]

I don't think I can recall any high wing single seat fighters.

I put the caveat mainly for the Polish PZLs, but yeah, I cannot think of any others.

I assume the low wing was used to keep the main spar low, so to allow the pilot, fuel and radio to go above the spar. Here's the Spitfire, would a high wing spar location be possible?

View attachment 693861

Looks like it could to me, given some careful design.

It just occurred to me too that preferred visibility could be a factor as well?

 

[nuuumannn]

Focke Wulf offered the Fw 159 against the Bf 109 and He 112:

Focke-Wulf Fw 159 - Wikipedia

en.wikipedia.org

The wiki page offers some considerations: "The plane had an enclosed cockpit and a rearward-retracting lever-action suspension main undercarriage which retracted completely into the lower fuselage. This mechanism was complicated, fragile and endlessly troublesome. The first prototype, the Fw-159 V1, was ready in the spring of 1935 but was destroyed when it crash-landed following the failure of the main undercarriage to deploy properly. The second prototype, the V2, had a reinforced undercarriage. The general flight characteristics were good but the rate of climb and rate of turn were unsatisfactory, and the aircraft suffered greater drag than its competitors in the contest, the Arado Ar 80, Heinkel He 112 and Messerschmitt Bf 109. The competition was won by the Bf 109.

 

[swampyankee]

A high wing may marginally worse, in that high-winged aircraft may need proportionally larger vertical tails. I suspect that there aren't any cases where a high/low wing comparison can be made between actual aircraft, as other design considerations bury any hypothetical disadvantage of one placement over another. In other words, High vs low vs mid wings is more a packaging issue than an aerodynamic one, although it's marginally more difficult to get a good wing root/fuselage junction with mid-wings than low.

With a single-engine aircraft of conventional configuration, as were all of the successful WW2-era fighters, one would want to put the pilot above the center-of-gravity, which would be at the wing, although the only high-winged fighter to see service in WW2, the PZL.11, placed the pilot well back (as did the low-winged F4U and IAR80).

 

[Thumpalumpacus]

Focke Wulf offered the Fw 159 against the Bf 109 and He 112:

Focke-Wulf Fw 159 - Wikipedia

en.wikipedia.org

I'd seen that one before, yeah. I was thinking more about operational. Provides a little insight about the landing-gear issue, if the wiki is accurate.

 

[GrauGeist]

Mid or Low wing aircraft could incorporate a much stronger main wing spar configuration which was needed in fighter and attack aircraft.

The side benefit of that, was pilot visability.

Observation aircraft did favor a high wing configuration for obvious reasons.

 

[Thumpalumpacus]

Mid or Low wing aircraft could incorporate a much stronger main wing spar configuration which was needed in fighter and attack aircraft.

Being able to attach the wing-spar to the keel of the fuselage directly?

 

[Admiral Beez]

A few monoplane, high-wing, single engine aircraft that maintained the spar within the fuselage without Lysander-like support struts, but not fighters.

I can't imagine a fighter with this layout.

 

[spicmart]

Focke Wulf offered the Fw 159 against the Bf 109 and He 112:

Focke-Wulf Fw 159 - Wikipedia

en.wikipedia.org

The wiki page offers some considerations: "The plane had an enclosed cockpit and a rearward-retracting lever-action suspension main undercarriage which retracted completely into the lower fuselage. This mechanism was complicated, fragile and endlessly troublesome. The first prototype, the Fw-159 V1, was ready in the spring of 1935 but was destroyed when it crash-landed following the failure of the main undercarriage to deploy properly. The second prototype, the V2, had a reinforced undercarriage. The general flight characteristics were good but the rate of climb and rate of turn were unsatisfactory, and the aircraft suffered greater drag than its competitors in the contest, the Arado Ar 80, Heinkel He 112 and Messerschmitt Bf 109. The competition was won by the Bf 109.

I really wonder how an engineer with foresight like Kurt Tank came up with such a design.

 

[Admiral Beez]

I really wonder how an engineer with foresight like Kurt Tank came up with such a design.

Even the best have their Google Glass moment.

The Google Glass Epic Fail: What Happened?

Here we are in the summer of 2015 and hardly a peep about a device that the media and public obsessed about for two years. So, what happened to Google Glass and where’s it going? The current Glass page answers the first question with, “Thanks for exploring with us.” An exploration that did not end …

bgr.com

 

[tomo pauk]

I really wonder how an engineer with foresight like Kurt Tank came up with such a design.

Perhaps he was trying to stretch the basic Fw 56 idea beyond what was practical? Reasons of time and money were (are) valid considerations.
OTOH, there was a lot of well-known designers and engineers who managed to make one or two flops in their career. Mitchel with Type 224 comes to the mind, Berlin with P-75. Polikarpov with I-180 and I-185.
Some were too defensive against the inovations and preferred conservative ideas and executions of the ideas, and some were trying to jump too many steps at once.

 

[spicmart]

Perhaps he was trying to stretch the basic Fw 56 idea beyond what was practical? Reasons of time and money were (are) valid considerations.
OTOH, there was a lot of well-known designers and engineers who managed to make one or two flops in their career. Mitchel with Type 224 comes to the mind, Berlin with P-75. Polikarpov with I-180 and I-185.
Some were too defensive against the inovations and preferred conservative ideas and executions of the ideas, and some were trying to jump too many steps at once.

I thought the I-185 was a high-performing plane at least on par with the Lavochkin and Yakovlev fighters?

 

[tomo pauk]

I thought the I-185 was a high-performing plane at least on par with the Lavochkin and Yakovlev fighters?

I-185 was sorta Bf 109 with R-2800 or Centaurus in the nose - ie. a huge engine on a tiny airframe. Very fast and very good climber - certainly, but even more of a handful for the pilots than it were the late marque Bf 109s.

 

[Shortround6]

Off hand the only planes I can think off where the differences in wing location were the Lockheed Vega and kin.
Of course these were 5-6 seat transports and were from the 1920s and early 30s..

This was given retractable landing gear and became the Orion.

No mid wing version

There were some high wing or parasol wing fighters in the 20s and/or early 30s

For pilots having the wing low put the wing further away from the pilot and improved the view or his ability to see around it, unless the wing was almost in the line of sight (gull wing) and he could look over or under it by tilting/moving his head. A wing 4 feet away is going to cover about 1/2 the arc (or 1/4 of the area) of the same wing only 2 feet away.

 

[spicmart]

I-185 was sorta Bf 109 with R-2800 or Centaurus in the nose - ie. a huge engine on a tiny airframe. Very fast and very good climber - certainly, but even more of a handful for the pilots than it were the late marque Bf 109s.

Then the Yak-3U must have been a handful, too, as it had an Ash-82. But I haven't have heard anything negative about it which makes me wonder.
Both the Yak-3 and I-185 were similar to the Fw 190V1 k (small wings of 14.0 sqm) in weight and dimensions which had to be fitted with the known 18.3 sqm wing for handling reasons.
The Yak-3U went the reverse path by accommodating a larger engine.
I wonder what they did to keep it superlative while the others would have to get larger airframes from keep balance.

 

[tomo pauk]

Then the Yak-3U must have been a handful, too, as it had an Ash-82. The Yak-3U went the reverse path by accommodating a larger engine.

The 14-cylinder ASh-82 was smaller and lighter than the 18-cylinder M-71. Yak-3U was outfitted with a bigger wing than the 'normal' -3s, 17.15 sq m (same area as with legacy Yak fighters like the -1, -7 and -9; also same wing span; my speculation: perhaps the wing was just carried over from these fighters?) vs. 14.85 sq m.

Both the Yak-3 and I-185 were similar to the Fw 190V1 k (small wings of 14.0 sqm) in weight and dimensions which had to be fitted with the known 18.3 sqm wing for handling reasons.

Yakovlev's engineers did the similar job with the Yak-3.

I wonder what they did to keep it superlative while the others would have to get larger airframes from keep balance.

Speed of the Yak-3U was on par with La-7 prototypes, while later in timing - the -3U 1st flew after the war.

 

[GrauGeist]

The LaGG-3 was not that large of an airframe amd accepted the Su-2's engine/cowling well enough.

 

[Just Schmidt]

Not many were operational, but there was at least one more:

And provided we allow both twin engines and never seing operative service, there's this:

I think they made a prototype Ar-234 too, and I'm pretty sure there were other prototype twins out there. And come to think about it, there is the Do 217 J and N that were operational. Anyway, though I'm unable to answer the question, Kurt Tank must have felt it wasn't a fatally flawed concept.