UH-1 Blades Had Tree-Cutting Tips?

[Stephanie Belser]

Elsewhere, someone mentioned to me that UH-1s were fitted with "tree-cutting blade tips", which were responsible for the distinctive rotor sound of a H-1.

Now me, I just thought they sounded that way because they had two very long rotor blades. I had never heard of tips designed for cutting vegetation, and I can;t easily find anything mentioning that.

But I know there are at least a few helo drivers here who flew those things back in the day.

So is the "tree-cutting blade tips" real or bushwa?

[Terry Carraway]

I read somewhere, that the blades were designed to be low noise, but somewhere a + can changed to a - or vice versa, and they ended up making a lot of noise.

[Bill Bridges]

So is the "tree-cutting blade tips" real or bushwa?

I've never heard of this. The tip of each blade has a tie down hook that sticks out about two inches. Cutting down a tree would be classified as a sudden stoppage and all the rotating parts would have to be replaced. I've cut down small branches on trees in really tight LZs while is SE Asia, but nothing larger than probably .5 inch diameter.

My roommate hit a tree (3-4 inch diameter) coming out of a hot LZ about 2 feet inboard from the tip and the blade was split along the cord line from the impact point toward the hub for a couple of feet. I could see the honeycomb from the blade manufacturing process. He had to make an emergency landing into a clearing a couple of klicks from the initial impact. Although separated along the cord line the blade stayed in tact but there was one "hell of a vibration." I've seen holes in UH-1 blades where I was able to stick my fist through and I have large hands. I also saw a Cobra (KFSI) chunk a blade that had become delaminated on the inside. I flew with the pilot while I was with the Cav in Vietnam.

There are several distinct sounds made by the UH-1, the loud pop-pop caused by the main rotors as they hit the vortices of the opposing blade. The second sound is a higher pitched, more like a propeller, which is the tail rotor. The third sound is the whine of the transmission.

I've got lots of UH-1 blade stories.

[Dave Siciliano]

There were some early experiments with special tips on blades by an agency we all know. Obviously, that wasn't given more wide spread use after the experiment.
I remember this from TV. If one did make it back, the blades would be like Bill described above. One time deal if one was lucky.

https://www.youtube.com/watch?v=uL8hf2wUUf4

[Ray Tackett]

Basically what Bill said. There was a tiedown eye on the end of each blade. The hook was at the end of a very long, red "REMOVE BEFORE FLIGHT" streamer. Hook a handy rotor blade tip, walk it around to the tail, wind the streamer several turns around the tail boom, and done.

Before engine start, unwind, unhook, stow the hook, and rotate the main rotor 90 degrees. Bill once told the story of a CLM caused by a pilot neglecting this part.

[Stephanie Belser]

Thanks, guys.