RESTORATION DIARY
KAMAN HOK-1

THE HISTORY

Kaman Corporation, headquartered in Bloomfield, has produced six types of helicopters. Three of them, the K-225, the HH-43F, and the SH-2F are on display here at the NEAM. Once completed, the HOK-1 will take its place in the Kaman collection representing the technological development between the K-225 and the HH-43F. It will also be the only U.S. Marine Corps aircraft in our large military collection.

Our HOK was built in October, 1953, the sixth of 83 of the type. It spent its days assigned to Kaman's Flight Test Department. By September, 1959 it had accumulated 838 hours of flight time. NEAM acquired the airplane in May, 1966. The HOK was in the museum hangar when the 1979 tornado destroyed many priceless aircraft and artifacts. It sustained some damage and has been in storage since May, 1980.

Rick Centore was assigned to lead the restoration volunteer team in bringing this aircraft back to its former glory. His connection with the HOK goes back to 1965. Fresh out of avionics school, he was assigned to Marine Observation Squadron 6 at Camp Pendleton, California. The squadron was in the process of transitioning to the Bell UH-1E Huey. But there were still a few HOKs, re-designated OH-43D in 1962, on the flight line. An HOK was the first aircraft Rick ever worked on.

October 2021 Highlight #2

The HOK-1 on September 30th. Although the aircraft appears complete, much work remains. One missing window must be molded and the other windows must be restored. Rotor blade restoration must be competed and the blades installed.

April 2021 Highlight #3

The control system for the HOK is a mind-boggling series of rods, shafts, bell cranks, and cables. Installation of this complex system was completed by the newest member of the HOK crew, Steve Monaghan. Steve is a retired Kaman helicopter mechanic with a wealth of knowledge.

April 2021 Highlight #1

The HOK restoration team has been busy since our last update. Thanks go out the Collision Center of Torrington for painting the landing gear and other components. Their efforts kept us working throughout the winter.

October 2020 Highlight #2

In early October we realized that unless we painted the fuselage before the cold weather set in, we would run out of work. So at that point we worked with one purpose, to prepare the fuselage for painting.

In an unusual move, we mounted a pair of casters high on the rear fuselage. A lifting bar was also built. This allowed us to employ a fork lift to tip the fuselage on its back. We could roll it around and the entire fuselage was accessible to the painter.

March 2020 Highlight #3

The engine crew has almost completed the engine and associated components. The engine crew also completed restoration of the transmission. Engine bay restoration has begun. A wooden work stand was built to hold the tail boom assembly during restoration. Paint has been removed and sheet metal repairs have been made. A wiring harness for tail boom lighting was made.

March 2020 Highlight #2

The forward cabin roof was replaced. Upper and lower console components were removed, restored, and reinstalled. Pilot and co-pilot flight controls were restored. A comparable pilot seat was found and restored. Floor and wall panels have been restored or if missing, fabricated. Painting of the interior cabin was started. Existing wiring was cleaned and restored. Wiring for exterior and interior lighting was installed. A mold is being made to form a replacement window.

July 2019 Highlight #2

The engine crew has made great strides in the restoration of the Pratt & Whitney R-1340. The engine mount has also been restored; the engine bay is being restored as well.

Other areas being worked on are the fuel cell compartment, the transmission, the upper pylons, and the co-pilot’s front hatch.

October 2021 Highlight #1

Many milestones were reached as fully restored assemblies were installed on the airframe: Both upper pylons were installed on the fuselage, the transmission was installed, driveshafts and rotor heads were installed, the engine was installed, the seating was installed, all painting of the fuselage was completed, all the livery was completed on the exterior of the aircraft, and the twin tail boom was installed.

April 2021 Highlight #2

As with any complex machine, components are installed in a predetermined sequence. In the case of the HOK, the sequence is the transmission, the upper pylons, the drive shafts, and the engine. The transmission was installed in late March. In early April the upper pylon installation was completed.

October 2020 Highlight #3

On October 15th the temperature was high enough to paint, but the wind was also high. We were committed at this point as this would be the last day of suitable temperature. Necessity being the mother of invention, we used a staging platform and large tarp to provide a windbreak. In the end the fuselage got painted, along with the upper pylons.

October 2020 Highlight #1

The year 2020 began well for the HOK restoration team. We were moving along well until the pandemic hit. The museum shut down entirely for many months. When it did open we got back to work, but with reduced hours.

Work on the cabin interior has continued. The floors have been installed and the wiring has been completed. The instrument panel, upper and lower control consoles have been completed. Some work in the cabin remains but not a great deal, mainly polishing of the windows.

March 2020 Highlight #1

The restoration of our HOK helicopter began in earnest about fourteen months ago. Restoration began soon after the 1979 tornado, but other projects took priority and work stopped. Many components had been removed and were lost over time, complicating the restoration as missing parts must be fabricated.

July 2019 Highlight #1

The major structural task in this restoration is the forward cabin roof panel which had been damaged in the 1979 tornado.

Tasks completed so far: pilot and co-pilot rudder pedal assemblies, landing gear has been restored and a set of main landing gear strut stops were machined to maintain the proper fuselage height.

Please check back in for more restoration updates.