Flightline: 49/TBD

"user314" (user314) 09/18/2020 at 11:00 • Filed to: flightline, Planelopnik, planelopnik history, Helicopter, Helicopterlopnik

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Kaman HH-43B Huskie at the USAF Museum in Dayton

Founded by !!!error: Indecipherable SUB-paragraph formatting!!! in 1945, the !!!error: Indecipherable SUB-paragraph formatting!!! quickly established itself as a major manufacturer of helicopters in the early Cold War. After graduating with an engineering degree in 1940 and working for Igor Sikorski during WWII, Charles founded his own company, taking with him his patents for !!!error: Indecipherable SUB-paragraph formatting!!! :

What is the Servo Flap and How Does it Work?

The servo flap is a small airfoil located at about 75 percent span of the rotor blade, situated on the trailing edge of each rotor blade. These flaps are controlled by the pilot through push-pull control rods and their function is similar to that of an elevator on fixed wing airplanes. Moving the trailing edge of the flap upward moves the leading edge of the main rotor blade up. This increases the rotor pitch or the lift in very much the same manner as the elevator, on a fixed wing aircraft, changes the angle of attack on the wing. Thus the helicopter pilot can cause the angle of attack of the flap to increase or decrease in pitch, causing the helicopter to alternately dive or climb.

!!!error: Indecipherable SUB-paragraph formatting!!! , a !!!error: Indecipherable SUB-paragraph formatting!!! aviation engineer, was captured and brought to the US as part of !!!error: Indecipherable SUB-paragraph formatting!!! . Flettner was developer of developer of Germany’s !!!error: Indecipherable SUB-paragraph formatting!!!   Kolibri (“Hummingbird”), one of the first helicopters to enter production. The Kolibri was a synchropter, two intermeshing rotors allowed flight without the need for a tail rotor, which, while needed for stability, robbed power from the main rotor. Kaman’s servo flaps would blend nicely with the synchropter principal, and Flettner was hired on as the Kaman Corp’s chief designer.

Kaman’s first design, the K-125, flew in 1947. The synchropter, equipped with Kaman’s flaps, flew well enough that two additional prototypes, the K-190 and K-225, were developed in 1949, and several were evaluated by the Navy, Coast Guard and USAF. In 1951, a K-225 was equipped with a !!!error: Indecipherable SUB-paragraph formatting!!! turboshaft engine, becoming the first helicopter to fly with a gas turbine.

Kaman continued developing the design, and in the early 1950s received contracts from the Navy and USMC to produce a light training, observation and utility helicopter under the (pre-1962) designations HTK-1, HOK-1, and HUK-1.

A preserved Navy HTK-1 at the Tilamook Air Museum

These early models were powered by piston engines, with the HTK-1 being fitted with a !!!error: Indecipherable SUB-paragraph formatting!!! , the HOK-1 an !!!error: Indecipherable SUB-paragraph formatting!!! , and the HUK-1 an R-1340-52. Under the 1962 Tri-Service designation arrangement, the three were redesignated the TH-43E, OH-43D and UH-43C respectively.

Kaman continued to work on the design, and in 1954 an HTK-1 was re-equipped with two Boeing T50, becoming the first twin-turboshaft helicopter.

Scan of the January 1954 issue of Popular Mechanics

The USAF, which had acquired 18 HOK-1 under the designation H-43A (HH-43A post-1962), was sufficiently interested that it ordered an enlarged version powered by a turboshaft, resulting in the H-43B (HH-43B post-1962).

An HH-43B participates in an firefighting exercise. The crew of the helicopter uses the rotor downwash to open a path for rescuers to spray foam.

The HH-43B was powered by a Lycoming T-53 gas turbine, had three seats and carried a full set of rescue equipment. The USAF purchased 200 HH-43Bs, and used them for on-base rescue and firefighting duties. The B model had a flight ceiling of 25,000', and a maximum speed of 120mph. Developed at Wright-Patterson AFB, the firefighting kit could produce 700 gallons of fire-fighting foam.

A U.S. Air Force Kaman HH-43B Huskie helicopter is used to rescue a downed airman from the jungles in Southeast Asia, 19 December 1968.

In response to the growing US presence in Vietnam, the USAF sent several detachments of HH-43s to perform combat search and rescue missions (CSAR). Officially known as “Huskies”, the HH-43 quickly became known to soldiers and airmen in Vietnam as “Pedro”, the call sign for the !!!error: Indecipherable SUB-paragraph formatting!!! . Though eventually replaced by newer helicopters in the 1970s, the Huskies flew more rescue missions than the rest of the US forces combined.

A Kaman HOK fitted with agricultural sprayers in 1971

Retired from military service in the middle 1970s, Huskies found their way into civilian hands, serving as agricultural aircraft, loggers, and general utility.

A large number of Huskies survive as !!!error: Indecipherable SUB-paragraph formatting!!! and in !!!error: Indecipherable SUB-paragraph formatting!!! .

RamblinRover Luxury-Yacht > user314 09/18/2020 at 11:25

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I’ve heard they’re absurdly stable in hover.

ttyymmnn > user314 09/18/2020 at 12:28

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What is the Servo Flap and How Does it Work?

So there’s no cyclic like in a traditional helicopter? And does anybody still use servo flaps?

I’m reminded a bit of the Curtis-Bleecker helicopter, which took the idea of a rotor being a spinning wing to wha was probably the logical conclusion at the time.

user314 > ttyymmnn 09/18/2020 at 12:47

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Looks like there is a cyclic, it’s just connected to the flaps rather than a swash plate . There’s a flight-worthy version on the West Coast, at least as of 2017.

The servo flap does seem to be exclusive to synchropters, or at least those manufactured by Kaman.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > RamblinRover Luxury-Yacht 09/18/2020 at 14:28

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I’ve heard many anecdotes about their friendly flight characteristics and high power efficiency (lift ability to horsepower), it kind of makes you wonder why they arent more popular in the civilian market, or further developed for the military... One of my uncles was a navy radio operator in Vietnam, and he said the pilots he knew all loved the Kamans.

gmporschenut also a fan of hondas > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 09/18/2020 at 20:41

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I think their forward speed is much lower 

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > gmporschenut also a fan of hondas 09/18/2020 at 20:45

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T hat may be, the specs I can find do seem to indicate relatively lower top speeds compared to single-rotor helicopters.