Early skid gear

November 10, 2011 by Tim McAdams

One of the early pioneers of helicopter flying was Carl Brady. In early 1947 he was crop dusting in a Stearman airplane when he saw a Bell 47B-3 spraying a field. Intrigued, he approached the owner and worked a deal out to get his helicopter pilot license. That same year he and two partners leased a couple of Bell 47B-3 helicopters and started their own operation.

Early helicopters, including the Bell 47B-3, used wheels for landing gear – probably a design borrowed from airplanes. Brady discovered that this was a bad idea for helicopters. He was known to tell a story that many consider the birth of skid type landing gear. It was 1948 and he and a former Bell mechanic were flying for the first time in Alaska. They discovered that the wheels would caster on rocky mountain tops or slopes causing the helicopter to roll downhill. To solve this problem they had a local sawmill cut two two-by-fours out of hardwood and using clothes line tied them to each wheel. It kept the wheels from castering and made landing on soft terrain much easier. Because there was no STC, they would fly their missions during the day and then remove the two-by-fours and fly back to town.

I have never read anything regarding the former Bell mechanic’s comments on the Alaskan adventure; however, two years later Bell introduced the Model 47D-1 with metal tube skid gear instead of wheels. This design became the standard for light helicopters for decades.

9 Responses to “Early skid gear”

  1. Rob Says:

    Interesting story. It makes me wonder why helicopters like the Blackhawk went back to wheels?

  2. jim hanson Says:

    So THIS is where they went wrong! (laugh). I’ve owned two Bells 47s, a Hughes 300, and for the last 20 years, an Enstrom. Skid landing gear is a pain to take on and off to maneuver into a hangar–it’s a pain to have to take the wheels along when there is little baggage area in a piston helicopter.

    Skid gear is easy to get stuck in weeds, snow, or brush, causing a dynamic rollover.

    Autorotations on skids can lead to a rollover if a skid digs into the ground.

    In contrast, I flew a McColloch certified gyroplane. I didn’t like it, but I DID LIKE the wheeled gear. Every landing was like an airplane–simply flare for landing and let it settle in, with a minimum rollout. How much better was that for autorotations than the need to either find a smooth and level place to land–or to kill off all forward speed before touching down. The wheeled gear is easier and safer–one of the reasons that most corporate helicopters have gone back to wheels. I would do in in a minute on my Enstrom

  3. Juan Carlos Says:

    There you have the answer Rob….

  4. John Says:

    If you never land off a prepared surface wheels are great. But for those who land in the bush or off airport Skids are best.

  5. Jon Stark Says:

    Skids weren’t the only answer to that castering problem in the early days. My 1952 Sikorsky S-52 (almost as old as the first 47s) with quadricycle gear had brakes on the rear non-castering wheels, and a simple castering lock for the front wheels. A handle would lift or drop simple pins to allow or prevent front wheel castering. Intended for shipboard landings, dropping the pins would avoid a risk of the aircraft turning and slipping off a rolling deck. When you wanted to taxi around, lifting the pins meant effortless turning with tail rotor thrust. Minimum power surface taxi, rolling take-offs and landings, and hangar roll in and out were wonderful with that arrangement. My skid-equipped Bell 47G3B1 is more tolerant of nasty terrain, but is much more inconvenient to operate at an airport than the S-52.

    I also owned a 1972 McCulloch J-2, a wheeled rotorcraft as mentioned above. It had a single steerable nose wheel. The Air & Space 18A certified gyroplane that I operate now has a (stiff) castering front wheel. Although the 18A can do jump take-offs with no roll at all, rolling a few feet on landing is common, and these aircraft can’t hover taxi, so wheels are the obvious answer.

  6. jim hanson Says:

    Operating at airports with skids is a pain if you have to operate in proximity to fixed-wing aircraft–like when getting fuel. You need to be light on the skids to move the helicopter–but still taking care not to blow the other aircraft over. Even worse–you park the helicopter, and some fool parks the airplane right next to you, and locks the brakes.

    Wheels are not ALWAYS the best–I’ve flown the Bell 222 on wheels–short run-on landings are certainly easier than a landing from a hover due to the long strut travel. Just when you think your landing from a hover is going to be good, one strut, then the other collapses, resulting in a wobbling touchdown.

    Skids are certainly not the cure-all–I’ve hooked skids in brush, and had them slide sideways under crusty snow–a real chance for dynamic rollover.

    John Stark–the instructor wouldn’t even try a jump takeoff in the J-2–it was summertime, and both of us were over 220 pounds. How well does it work? I can only imagine popping 25′ into the air, and depending on attaining translational lift to keep you aloft before running out of rotor RPM! What are your feelings about gyroplane autos vs. helicopter? With your gyro experience, did you ever do any flying at Farrington’s in Paducah?

  7. Jon Stark Says:

    Jim Hanson -

    The J-2 was never intended to do jumps. It will pre-spin ito 125% of flight rpm, and a short roll (often only 50 to 100 feet) to get a bit of translational airspeed is expected. It uses the same rotor design as the Hughes 269 / Schweizer 300 (with the twist removed from the blades) and that’s not massive enough to store a great deal of energy.

    The A&S 18A was designed with jumps in mind, and it works extremely well. It has three heavy blades that turn about 240 rpm in flight. By pre-spinning them to 370 rpm on the ground in flat pitch, you store enough energy to leap up when pitch is quickly added. Pitch-cone coupling automatically reduces the collective pitch as the rpm bleeds down, and with full thrust through the prop you get flight airspeed quickly. Here’s a link to a video of me doing a take-off with a VERY short roll that will show how it works.

    http://www.youtube.com/watch?v=hI5cAgWmShU

    There’s really no need for an “auto” maneuver in the helicopter sense, because gyros are in autorotation all the time, and have no transition issues or need for rapid pilot action in the event of a power failure. You always climb, cruise, and land in autorotation, and if the noise quits, there’s much less drama than a helicopter; you just glide to a landing with NO configuration change at all. I tease other rotary wing pilots that I get hours of auto time whenever I fly it, while they can only accumulate auto time at a rate more like 20 seconds per approach. Gyros are not terribly efficient, but the certified ones are easy to fly, mechanically simple, very safe, and plenty of fun.

    Yes, I got my Gyro CFI rating with John Potter and Don Farrington long ago. Too bad those guys and that place are gone now.

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