Item 0742
OTHER:
Helicopter - Outside - Intermeshing - Kaman - H-43 Huskie
Locations of specific Information:
This Web Site:
A059.html - Kaman Huskie re: Stovepipe exhaust
DESIGN: SynchroLite ~ Rotor - Disk - Lead-Flap Coupling, for Intermeshing Helicopter
Use
search engine, located on initial page, to find all locations in this web site.Other Web Sites:
http://avia.russian.ee/vertigo/kaman_htk-r.html
http://www.kaman.com/about/index.html
The Servo Flap Controlled Rotor
H-43 on PPRuNe ~ July 26, 2001
As for turning when the pilot makes a pedal input, the pitch is increased on one set of rotor blades and decreased on the other by a mechanical mixing system. The resulting higher torque from one rotor system rotates the helicopter. Also, at the same time through the same mixer one rotor disk is tilted forward and the other back helping to turn the aircraft. The only bad part of this system is that at some power settings it is ineffective. This in turn can cause some interesting moments for an inexperienced pilot. I remember the first time it happened to me. As I was approaching to land the nose started wandering off to the left so I added right pedal and added and added right pedal until I hit the pedal stop and we were still turning left! About this time, the other pilot flying with me told me just to add a little collective and the problem would correct itself. Sure enough it did but it was still one of the more interesting moments of my training!
H-43 on PPRuNe ~ September 7, 2001
As far a pedal unresponsiveness is concerned, I really don't know how the K-Max is set up or how it flies. But the Huskie is unresponsive because it uses differential pitch to cause yaw. In an autorotation the requirements change so there is a mechanical reverser assembly that changes the direction of the differential pitch change pushrod. At a certain low point in its travel the reverser output rod will not move at all no matter what the deflection of the pedal input. This complicates thing during low power settings such as during a descent.
My thoughts:
The coaxial uses collective differential to yaw and must reverse pedal inputs during autorotation. The side-by-side uses opposed longitudinal cyclic to yaw and I don't know if their pedals must be reversed for autorotation. The intermeshing is a hybrid of these two.
_______________________
See yaw control information about the K-Max OTHER: Helicopter - Outside - Intermeshing - Kaman - K-MAX
Flingwing207 on PPRuNe ~ March 1, 2004
What little I know about autos and synchromesh helos was relayed to me by a K-Max pilot who stopped at KTIX while ferrying a ship south-to-north. When he landed, I noticed that he didn't set the ship down like a feather, in fact he pretty much "plunked" it down.
I asked about autorotations, and indeed you are right, when the collective is below a certain setting, the mechanical mixing of the pedals reverses. I asked the same question about the transition point, and basically the pedals' "effect" goes to neutral as you go from full down throught the transition and into the "power" range of collective travel. Since in autorotation you pass through this "null zone" pretty quickly (both on entry and while cushioning), it's not an issue.
However, when setting down a lightly loaded K-Max, you start to lose some pedal touch just as you touch down, so the tendency is to lower collective briskly on a normal touchdown.
(Or so he said - he could have easily been pulling my chain about this last part and just made a cheesy set-down, but since he was a factory pilot, I'll take his word for it!)
Miscellaneous Information:
The 'V' of the masts is 26-degrees.
One of the earliest articles on the Kaman synchropter was the one in Popular Science, 0ct./1949 (have hard copy in Kaman file folder) The primary advantage of his new helicopter was the use of servo flaps and the reduction in vibration, as a result.
It would appear that the use of delta-3 may have been taken from the side-by-side Weir W-6. ~
[Source ~ MDD p.248]
From D.W.
Here's the info I have on the Huskie.
Max Speed - 120 mph (104.3 k)
cruise speed - 110 mph (95.6 k)
weight
empty weight - 4469 lb.
payload - 4681 lb.
gross weight - 9150 lb.
rotor blade
airfoil - naca 0012
angle of attack - 0
number of blades - 2 per rotor
radius - 23.5 ft
chord - 16 in (1.33 ft)
blade cutout ratio - 0.2575
taper - none
twist type - 1
rotor hubs
configuration - 3
center to center - 0
vertical distance - 0
angle of each mast - 12.5 deg (25 deg included angle)
I've also seen 26 degrees
horizontal distance between hubs - 3.667 ft
I don't have the rotor rpm but will leave a message on the one the air
rescue sites and see if the old crew chiefs can remember. Since the
H-43 was known for being very quiet, the tip speeds had to be low.
From D.W.
J.C. responded to my question on the Pedro air rescue forum and states that 100% rotor speed was 248 rpm. This gives a tip speed higher than I expected. The lower noise level may be primarily because of the absence of the tail rotor. I've also seen a mention that Kaman conducted a "Quiet Helicopter Program" for the Army Material Lab during the late 60's but I haven't found a copy of any report. Changes were apparently made after this study and may have reduced the noise levels. If you see a mention of this report, I'd like to get a reference to it.
Error in this web site's horsepower calculations for twin rotor craft:
The Blade Element program, using the Huskie statistics is currently giving the following values;
The horsepower must obviously be somewhere between the horsepowers of A/ and B/ and it sure as heck isn't.
This means that the Blade Element horsepower value on the web page is not valid and has been removed
From NeilJMc on rec.aviation rotorcraft November 1, 2002
I flew the Sikorsky UH 19 Chickasaw, CH-2 and the Huskie HH-43. The -43 was a breeze after both of the above. It did have a definite 'thumpy' ride though. Autorotations were much easier. Hovering was easy. It was essentially two - two blade systems side by side - counter rotating. There was no side to side torque but there was a nose tuck or nose rise type of torque during take off adding collective or upon unloading collective.
2,455,866 ~ The original patent on Kaman's servo-flap. Interestingly, each blade has only one servo-flap, however, it is located on the leading edge.
I have hard copy of some of the pages.An interesting statement in the above patent is "A still further object of this invention is to utilize the flaps connected with the blades to effect twisting thereof in such a manner as to minimize perpendicular oscillatory motion of a helicopter during hovering." This seams to imply a rotor-to-rotor induced vibration.
2,668,595 ~ Kaman. This patent shows two active servo-flaps per blade. One on the front and one on the back.
2,695,674 ~ Kaman. This patent is for a single servo-flap on each blade, but it is now on the trailing edge.
I have hard copy of the first page.2,983,319 ~ Kaman rotor patent on 'Harmonic anti-vibration means for a helicopter' ~ 1961
More Miscellaneous Information:
Rotor Disk and Horsepower Calculations: Not done yet.
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Last Revised: May 6, 2005