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Washout built into the wings of the Ta-152H (WWII Aviation Question) 1

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Broncazonk

Materials
Feb 16, 2015
26
I have a question pertaining to the late-war German high altitude fighter, the Ta-152H.

3-view here:
Here is a description of the washout built into the wings of the Ta-152H written by the National Air and Space Museum:

“Kurt Tank chose the same workhorse Jumo 213 powerplant used in the Fw 190D. For the Ta 152H, he selected an uprated version, the Jumo 213E, equipped with a 2-stage, 3-speed mechanical supercharger and MW 50 engine boost. The MW 50 system used methanol-water mixture to boost engine output from 1,312 kw (1,750 hp) to 1,537 kw (2,050 hp) for short periods. Because of aluminum shortages, Focke-Wulf made the wing spars from steel and built the rear fuselage and empennage. The wing contained two steel spars. The front spar extended slightly beyond the landing gear attachment points but the rear spar spanned the entire wing. The wing twisted 3° from the root to the flap-aileron junction. This 'washout' prevented the ailerons from stalling before the center section. This allowed the pilot to maintain roll control during a stall. Armament consisted of one 30mm MK 108 cannon firing 90 rounds through the propeller hub and one 20mm MG 151 cannon firing 150-175 rounds from each wing root.”



And here is another description:

The aircraft had an increased wingspan compared to the previous FW 190 design, as a further accommodation towards better high altitude performance. Due to the war's impact on aluminum availability, the wing was built around two steel spars, the front extending from just past the landing gear attachment points, and the rear spar spanning the entire wing. The wing itself was designed with 3° of washout, from the root to the flap-aileron junction, to prevent the ailerons from stalling before the center section of the wing. This design allowed the pilot to maintain roll control during a stall and extreme flight envelope maneuvers.


Are these descriptions correct? Isn't it more likely that 3° of washout (three degrees of downward twist) was built into the wings beginning at the flap-aileron junction that extended to the wing tips—not and not from the root to the flap-aileron junction?

Would the experts on the list please provide some clarity on this?

Thank you,

Bronc
 
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My apologies. It just dawned on me the engineers on the list probably do not have access to the flight characteristics of the Ta-152H.

According to Willi Reschke who flew the Ta-152H-0 in combat beginning in February of 1945: "The aircraft (fully armed, fully fueled, at all up weight) lifted off effortlessly, after only a few hundred meters, at about 210km/h (130.5 mph)."

"Rate of climb was 17.5m/s to a height of 5,000 meters. It took twelve minutes to reach a height of 10,000 meters."

"Compared to the Fw-190 A-8, the Ta-152H-0 had a [much] smaller turning radius with less tendency to stall, and the stall developed at a much lower airspeed (approx. 250 km/h [155mph]). Recovery from the resulting spin was easily effected after about 500-600 meters."

If the aircraft stalled at 155mph, how did it take off at 130mph?

Thank you,

Bronc

 
WIGE?

Flaps deployed for take off but not during maneuvers where stall occurred?

Discrepancy between IAS & ground speed or similar?

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484
 
KENAT wrote, "Flaps deployed for take off but not during maneuvers where stall occurred?" Almost has to be, and that brings me back around to the split flap question. If take-off with a fully deployed flap is 130mph, and a stall with a clean wing is 155 mph, that paltry 25 mph difference is a solid indictment of that split flap design, isn't it? (Wouldn't we want to see a much larger spread between those two figures?)

Thank you,

Bronc
 
Speaking as someone who is not a pilot or aircraft designer, I think takeoff at stall speed would be asking for lots of trouble.
A quick search shows that a cessna 172 takes off at about 1.4x the IGE stall speed.
In addition to a margin of safety, the full torque of the engine must be opposed in part by the wings.
Roskam's books provide a wide survey of aircraft types and data.
Raymer's aircraft configuration and design, provides good (to an amateur, at least) insight into the process and worked examples.
 
split flaps are a compromise, like most things in life, and aero design. They are a very primitive (ie early) design, very simple structurally, and not very effective but they were the bridge from no-flap wings to simple hinge flaps. I suspect that the aerodynamicists of the day sold them as a huge advantage that maybe didn't materialise or else designers got smarter and said "hinging the trailing edge isn't thatmuch more complicated, would there be an advantage ?". maybe the key advantage that split flaps have over hinge flaps is that they don't have a gap to seal.

as we've said take-off speed is still quite abit above stall speed, so if take-off with flaps down is 130kts, then stall might be 105kts (doubling their advantage).

another day in paradise, or is paradise one day closer ?
 
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