Kalinin K-7

1933

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Kalinin K-7

Designed by World War I aviator Konstantin Kalinin with a wingspan greater than a B-52's and a much greater wing area, the K-7 was one of the biggest aircraft built before the jet age. It was only one engine short of the B-52 as well, having the curious arrangement of six pulling on the wing leading edge and one pushing at the rear.

The K-7's very brief first flight showed up instability and serious vibration caused by the airframe resonating with the engine frequency. The solution to this 'flutter' was thought to be to shorten and strengthen the tail booms, little being known then about the natural frequencies of structures and their response to vibration. On the 11th flight, during a speed test, the port tailboom vibrated, fractured, jammed the elevator and caused the giant aircraft to plough into the ground, killing 15.

Undaunted by this disaster, Kalinin's team began construction of two further K-7s in a new factory, but the vicissitudes of Stalin's Russia saw the project abandoned, and in 1938 the arrest and execution of Kalinin on trumped up espionage and sabotage charges.

Jim Winchester "The World's Worst Aircraft", 2005

FACTS AND FIGURES

© The K-7 was one of the first metal aircraft with a twin-boom layout.

© As originally designed the K-7 was to have engines in the undercarriage sponsons. As completed the bomber had gun positions, the bomb load and an internal staircase as well as two large wheels in each massive sponson.

© The K-7's control surfaces were all deflected by the use of large trim tab surfaces mounted on struts.

© The K-7 was said to have had a pilot, 18 crew members and one passenger when it crashed, killing all but five crew. It is not clear what they all did, but no doubt tending to the engines was a full-time task.

Kalinin K-7 on YOUTUBE

3-View 
Kalinin K-7A three-view drawing (800 x 964)

Specification 
 CREW12
 PASSENGERS128
 ENGINE7 x M34F, 550kW
 WEIGHTS
  Take-off weight38000 kg83776 lb
  Empty weight24400 kg53793 lb
 DIMENSIONS
  Wingspan53.0 m174 ft 11 in
  Length28.0 m92 ft 10 in
  Wing area454.0 m24886.81 sq ft
 PERFORMANCE
  Max. speed234 km/h145 mph
  Cruise speed180 km/h112 mph
  Ceiling4000 m13100 ft
  Range3030 km1883 miles

Comments1-20 21-40
Steve, e-mail, 03.03.2009 21:00

A more complete description of this design, and an inflight photo is available at

www.pilotfriend.com /photo_albums /potty /8.htm

The final version, which crashed due to flutter, had 6 tractor engines and one pusher engine.

A scale model version is shown at
www.internetmodeler.com /artman /publish /aviation /Scratchbuilt_Kalinin_K-7.php

reply

Randy, e-mail, 01.03.2009 06:12

There are urban legend 'photos' of this plane floating around the web. They are actually computer-generated graphics, embellished by the artists. The photo on this page is the only actual photograph I have seen of the plane yet.

reply

Mel Young, e-mail, 24.02.2009 18:33

Check other photos. This plane has six engines on the leading edge and four more, back-to-back engine installations on top of the wings....four pulling and four pushing.

I can send you the photos if you wish.

Mel Young
Westminster, CA

reply

Bill, e-mail, 24.02.2009 01:12

does it come in a kit form..????

reply

1-20 21-40

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