Bristol Britannia > Canadair CL-44 (CC-106 Yukon)
(Image removed from quote.)
Developed from the Britannia was the CP-107 Argus.
morf,
Vickers Vanguard. Not sure if it saw military service tho.
Some others:
Lockheed L-188 Electra
Antonov An-10
Antonov An-12
Ilyushin Il-18
All of these aircraft, as you correctly point out, did an outstanding job for their respective countries. A little note about the Lockheed Electra, which many airlines used for many, many years! The Electra had a serious problem when first introduced to service and several crashed prior to the NTSB,, (old CAB investigators were in use when this happened), They finally figured out that the two outboard engines, #1 and #4, when the aircraft exceeded 340 knots, which they did in normal level cruise flight.. The two engines in question, because of gyro action, induced by the 4 bladed props, would begin an oscillation, which would cause the engines to tear off the wing and of course the aircraft would crash. For many months, all the airlines were restricted to no more than 275 knots, if I recall correctly, until a fix was installed to correct the problem. Following text is reports from the old Civil Aeronautics Board, which was charged with airline accidents at that time.
a Lockheed L-188 Electra, registration N9705C, was a scheduled domestic flight from Houston, Texas, bound for New York with scheduled stops in Dallas and Washington, D.C.. On September 29, 1959, 23 minutes into the 41-minute flight from Houston to Dallas Love Field, the aircraft disintegrated in midair approximately 3.8 miles (6.1 km) southeast of Buffalo, Texas killing everyone on board.
Identifying the cause of the disaster proved difficult, as the accident had occurred before the age of cockpit voice recorders. The Civil Aeronautics Board (CAB) investigated the accident and, after interviewing numerous eyewitnesses and examining the debris field, were able to conclude that the initial failure of the aircraft had begun in the left wing. However, even though it was determined that the wing was destroyed by "cycles of reverse bending" or "flutter", the investigation failed to determine how the flutter was caused, and the investigation stalled.
In the six months following the accident further progress towards identifying the cause of the flutter was unsuccessful and the case remained unsolved. The breakthrough into unlocking the cause of the accident came after the crash of Northwest Airlines Flight 710 on March 17, 1960. The two aircraft, both Electra's, disintegrated in midair after losing their wings in similar fashion, both resulting in the deaths of all occupants on board. The investigation into the Northwest crash discovered a new phenomenon of harmonic coupling within the wings of aircraft, which in the end was ultimately identified by the CAB as being the cause of both breakups. The final accident report for Flight 542 was issued on April 28, 1961.
Civil Aeronautics Board investigators arrived on the scene the morning following the accident. The left wing was found a mile away from the potato field in which most of the other pieces of aircraft lay, and the pieces of the right wing were scattered in a widespread debris field across the countryside.
Investigation determined that the breakup of the plane had begun in the left wing and progressed in a catastrophic sequence which ultimately destroyed the aircraft. However, the reason for the disintegration of the left wing proved to be elusive. Tests found that "flutter" had destroyed the wing, however the Electra's wings were supposedly flutter-free. Further tests attempting to recreate the accident by weakening the wing and exposing it to loads greater than any which would conceivably have occurred in the actual flight failed to cause a breakup similar to the one that occurred in Flight 542. Help from teams at Boeing, Convair, National Aeronautics and Space Administration (NASA) and the Federal Aviation Administration (FAA) also failed to determine how Lockheed's "flutter-free" wing had simply ripped away during flight, and the investigation stalled, further progress not being achieved for nearly six months.
Renewal of interest in finding the cause for the Braniff Flight 542 crash occurred after Northwest Airlines Flight 710, another Electra model aircraft of the same kind as Flight 542, disintegrated in-flight and crashed near Tell City, Indiana on March 17, 1960. Following the second crash, CAB Chief Safety investigator, Phillip Goldstein, was reported as saying: "The structure was subjected to forces greater than it was designed for. We have definite evidence of a wing failure. Why this wing failure, I don't know."
Initial investigations into the second crash proved fruitless but after laborious testing investigators were able to find flaws in the aircraft which included an overly stiff wing, and outboard nacelles responding differently than intended in the design briefs. Further experimentation discovered that flutter in a nacelle can be passed on to even a "flutter-free" wing. Final work in the mystery also found that as the magnitude of the flutter grows, the frequency at which it vibrates decreases. In the case of the two Electra crashes the frequency of the flutter had lowered from five cycles a second to three, the same as the wing creating harmonic coupling. This harmonic coupling would have continued to cause ever larger wing vibrations until some part of the structure failed. Contributing to the two aircraft's demise was the stiffness of the wings and severe clear-air turbulence. Final analysis of the CAB, in its official Accident Report:
ConclusionThere was in this investigation no positive indication of the cause. For this reason, an attempt has been made in this report to eliminate certain possibilities by application of the available evidence to each of them. Once these possibilities have been disposed of, the only remaining causal factor for which there is some known basis is the condition of whirl mode. The probability that this accident was so caused is supported by the following.1. So far as is known, the aircraft was in straight and level flight and at a normal cruise speed with no serious mechanical problems.2. A sound identified as a supersonic or high speed propeller occurred 30 seconds prior to fuel ignition (wing failure).3. There was structural damage evidence compatible with oscillatory motion of the No. 1 QEC and the left wing.4. First stage compressor blades of No. 1 engine rubbed the air inlet housing supports.5. The probable cause of a similar accident of another Electra was due to whirl mode.If prior damage is a requirement for the necessary reduction in stiffness, it must be assumed that the evidence of such damage was either obliterated in the crash or never existed in a discernible form.Probable CauseThe Board determines that the probable cause of this accident was structural failure of the left wing resulting from forces generated by undampened propeller whirl mode.
The final reports into the two accidents were released four days apart, on April 24 and April 28, 1961 respectively, with the Braniff crash report being the later of the two. Both reports were similar and blamed the same forces for destroying both aircraft. I have not been able to find the "fix" in official lingo, but if I remember correctly, the "fix" was cutting 8.5 inches of length off of the props, which stopped the occalation of the engine nacelles, which was the cause of the wing failures.
To Lockheeds credit and engineers who investigated this great aircraft, an aircraft was born out of this, which is still in use today, the "P-3" Orion.
Role
Maritime patrol aircraft
National origin
United States
Manufacturer
Lockheed
Lockheed Martin
First flight
November 1959
Introduction
August 1962
Status
Active
Primary users
United States Navy
Japan Maritime Self-Defense Force
Royal Australian Air Force
Brazilian Air Force
Number built
Lockheed – 650,
Kawasaki – 107,
Total – 757
Unit cost
US$36 million (FY1987)
Developed from
Lockheed L-188 Electra
Variants
Lockheed AP-3C Orion
Lockheed CP-140 Aurora
Lockheed EP-3
Lockheed WP-3D Orion
Developed into
Lockheed P-7
The Lockheed P-3 Orion is a four-engine turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner. The aircraft is easily recognizable by its distinctive tail stinger or "MAD Boom", used for the magnetic detection of submarines.
Over the years, the aircraft has seen numerous design advancements, most notably to its electronics packages. The P-3 Orion is still in use by numerous navies and air forces around the world, primarily for maritime patrol, reconnaissance, anti-surface warfare and anti-submarine warfare. A total of 734 P-3s have been built, and during 2012, it joined the handful of military aircraft including the Boeing B-52 Stratofortress and Boeing KC-135 Stratotanker that have served 50 years of continuous use by the United States military. The U.S. Navy's remaining P-3C aircraft will eventually be replaced by the Boeing P-8A Poseidon
