Aircraft Quiz #60

[Doug Robertson]

In my same vein (jugular?) as Quiz #59, I offer this new quiz about shoddily designed/constructed aircraft. What prototype airliner aircraft made in a particular country unfortunately fell apart in flight while demonstrating it to prospective buyers from another country? (I am NOT making this up!)

A substantial increase in the engines' horsepower was only part of the problem. Poor (inadequate) stress analyses along with a plethora of differing construction materials and weak glued joints, cracks, un-retractable retractable landing gear and weight gains sealed its fate. (One reference called its appearance Hideous!)

1a. Country of design/origin?, 1b. Builder?, 1c. Nomenclature & common Name of the design.

2. Year of first flight?

3. Original prototype engines nomenclature/horsepower used?

4. Production changed engines nomenclature and horsepower?

5. Materials/methods of construction?

6. Country who wanted to buy it involved in the fatal test flight debacle?

7. Total number built?

Bonus for the country (a third one) who used some "improved" surviving aircraft for what different flight purpose?

[SunvisorFlyer]

Been looking for a little while now, but I still have not found anything matching this description.

[Doug Robertson]

I'll admit-this is perhaps my toughest (and kookiest) aviation quiz yet. I appreciate your interest and diligence. As usual, if 500 views and no correct answers, my response will be forthcoming.

[Doug Robertson]

Again, a stumper has prevailed with over 500 views and no answers. Here are my answers.

1a. Poland, 1b. PZL, 1c. PZL.30 (or PZL.30BI).

2. 1936.

3. Two Pratt & Whitney R-985 Wasp Junior radials 420 Hp each, for PZL.30.

4. Two Bristol Pegasus VIII radials rated 680 Hp each, 700 Hp each for takeoff, for PZL.30BI.

5. Mixed construction of partly metal stressed skin, steel tube fabric covered, fabric-covered metal and glued wood.

6. Romania.

7. 17 including prototypes-counting the 15 Polish armed bomber version-PZL LWS.6 ZUBR (Bison).

Bonus answer: The German Luftwaffe "appropriated" two of the Bison bombers in 1939, using them as unarmed twin engine trainer aircraft refinished in Luftwaffe colors. (Poland having fallen first to Nazi Germany starting the advent of WWII).

The origin of the aircraft was a twin engine passenger design for the Polish National Airline LOT rife with bad math stress calculation errors and mixed inadequate construction by PZL LWS. This first flown in March 1936. After the prototype with the larger engines crashed with two Romanian officials aboard, the factory covered up by a story that a Romanian had opened a door in flight. LOT then changed their mind and ordered Douglas DC-2 all-metal twin engine 14 passenger commercial transports. Oh, I didn't add- the retractable gear would not retract because of weakness in the main gear retraction mechanism of the PZL taildragger, among other design issues.

PZL.30 BI specs

Crew: Four
Powerplant: Two Bristol Pegasus VIII piston radials 680 Hp, 700 Hp for takeoff.
Speed: Max 236 mph-another source gives Max 212 mph (and more likely)
Length: 50'9"
Height: 13'
Wingspan: 60'9"
Weight: Max 15,135 lb.

Incidentally, one reference called the design "hideous." Any photo of this aircraft welcomed and confirmatory.

[SunvisorFlyer]

PZL huh? Never would have thought to look there.
They're owned by Sikorsky now right?

Also, I think this is a photo of the aforementioned aircraft.

[Doug Robertson]

Yes, that is the ZUBR (Bison) bomber version with a nose gun turret and other armament. In the passenger version the pilot had a blister on the left above the aircraft nose. All the nose fenestration was there also. Thanks for the photo. I have never seen a photo of one in flight, only parked or crashed.
And yes, United Technologies Holdings (Sikorsky parent) bought PZL Mielec effective 18 March 2007. Thank you for the photo link.

[red750]

This link has a series of photos of the aircraft (although none in flight), as well as a number of other Polish aircraft, some a little unusual..

https://forum.warthunder.com/index.php?/topic/83743-polish-planes-from-1939-to-the-korean-conflict/

[Doug Robertson]

Thank you for the photo link, and I am in agreement with your assessment. You are being very kind.