Kamov Ka-26 Dance

[okikuma]

Fun video of a Kamov Ka-26 "dancing around."

Wayne

The Kamov Ka-26 is a very special construction with the coaxial rotor system and the two radial engines.

The chopper looks very strange and sluggish, but thats not true. This helicopter with a great pilot is able to do hair-rising maneuvers with very special flight style.

Hungary is lucky to have a lot of Kamov Ka-26s long ago, so we have a lot of great experienced pilots.

Very big thank to Ernő Jakab to made this wonderfull and sometimes allmost scary demonstration flight for us. He showed us all of the special maneuvers from the Kamov Ka-26 from spraying-turns to the moving pirouetts and autorotations.

This Kamov Ka-26 is in the registration of HA-MPJ. She is a very old bird in Hungary, cames from the Hungarian Air Service, where she was used for agricultural flights.

After 1990 she was kept in pieces at LHBS until Fly-Coop Kft. bought and assemblied her again. After that she was stationed at Kaposújlak airport. Nowadays HA-MPJ is doing agricultural flights around Southwest-Hungary with Kadarkút station airfield.

 

[Eric S]

Sure is fun to watch an experienced pilot in a capable aircraft dancing on what I assume is the razor's edge of the envelope.

 

[Doug Riley]

It's interesting how similar this helo's routine is to a gyro "showoff" sequence. Well, except for pirouettes without losing altitude.

It's also interesting that this helo has what appear to be movable rudders for yaw. IIR, some coaxes used some form of braking (or differential collective?) on one rotor or the other for yaw. Such a setup would yaw just fine, even at zero airspeed, but likely would cause an altitude change with each pedal push -- just like a tail-rotor helicopter. Not great near the ground.

 

[okikuma]

Doug,

It is to my understanding that Kamov co-axial helicopters use controlled dissymmetry of torque as yaw control. This is accomplished by increasing the collective pitch of one rotor and decreasing the collective pitch on the other. The rudders on the vertical stabilizers also deflect with corresponding pedal input to aid in yaw control, especially during autorotation.

Wayne

 

[Doug Riley]

Interesting. Thanks, Wayne.

A coax helo with twin engine pods (probably a Kamov) sits under a tarp up the road from here. It belongs to a small helicopter operator, Mansfield Heliflight, (R-22's and 206's), but it never seems to move. Just a lawn ornament at this point, I guess.

 

[okikuma]

Interesting. Thanks, Wayne.

A coax helo with twin engine pods (probably a Kamov) sits under a tarp up the road from here. It belongs to a small helicopter operator, Mansfield Heliflight, (R-22's and 206's), but it never seems to move. Just a lawn ornament at this point, I guess.

Too bad. The owner "needs" some continuous reminders to get going on returning the machine back to flight status.

During the 50's - 70's, the Soviet military doctrine in regards to petrol powered internal combustion engines are to be designed to operate on a minimum of 72 - 78 octane fuel. This is the natural range of the octane of gasoline after distillation of oil at the refinery without any additives. Simplicity.

Since the Vedeneyev M-14V-26 radial engines can operate on 78 octane fuel, I've been told that crop-dusting operators of the Ka-26 use readily available automotive gasoline without ethanol.

In one of the videos, one can see one of the Vedeneyev M-14V radial engines being "pulled through" with a ratchet and socket. Before the first start up of the day, all radial engines need to be "pulled through" to prevent "hydraulic lock" (hydrolock) on the lower cylinders. By design, radial engines have wider tolerances between cylinders and piston rings than other internal combustion engines. After sitting for some time without operation, oil often collects in the lower cylinders (gravity). If that oil is not removed out of those lower cylinders, during the first start up of the day, the extra oil within the cylinder effectively increases the compression against the piston and can bend the attached connecting rod.

Pulling the radial engine through slowly will show if any oil has settled in the lower cylinders to cause hydraulic lock. If that is the case, one needs to remove the spark plugs on the offending cylinder, and then pull the engine though again slowly to push out the oil through the spark plug holes and exhaust valve.

Wayne