Low horizontal, high horizontal

SMOF

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Dr Bensen believed that the low horizontal stabilizer protected the prop from FOD off the ground.

Can anyone give me an example of a gyro with a high stab which took any prop damage that the low stab might have prevented?
 

All_In

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I'm no expert however what I've been taught here is Bensen did not believe in HS's and that is just a rock guard and not a horizontal stabilizer. I have seen them with both a rock guard and a HS.
 

phantom

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Some people confuse the bensen Rock guard with a horizontal stabilizer, it is just a rock guard, a keel mounted HS will not protect your prop because it is mounted as far back on the keel as possible, I have always had my HS mounted in the prop blast and usually about 6 to 8 feet tip to tip on normal gyros and up to 12 feet on float and boat type gyros, my machines needed larger stabilizers due to depending on only the stabilizer to keep things dampened due to using a fixed spindle head, machines that use the offset gimbal head can get away with less stabilizer but I don't like that idea due to the ability of that type head to mask any instability until it goes beyond a certain point and bad things happen so quickly that there is no chance for recovery, I believe that if bensen would have left his live spindle head on his machines and put enough stabilizer on there would have only ever been wire strike type fatal accidents in gyros because a well stabilized gyro is one of the easiest machines to fly.
Norm
 

All_In

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,,, I believe that if bensen would have left his live spindle head on his machines and put enough stabilizer on there would have only ever been wire strike type fatal accidents in gyros because a well stabilized gyro is one of the easiest machines to fly.
Norm
Hi Norm

OK I've not heard of this before and not sure what a live head is. Does anyone have a drawing of both or description an idiot could understand?

Is there a down side to a live head? If not then why aren't most all manufactures using them?

Sounds like this would add extra stability and the industries should change to using them.
 

phantom

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A live spindle type head is what bensen started out with and I learned to fly with, the spindle tilts for control, one of the problems is that there is no good way to put a good prerotator on it without using hydraulics, the other is that rotor drag feeds into the control system in an unstable direction , it is no problem with the overhead as the stick pulls away from you which is not a problem but with a joystick the force is back at you which I find uncomfortable, the fix is to mask it with spring. A fixed spindle is what the air and space has , the rotor shaft can't tilt for control.
Norm.
 

SMOF

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My point was not about what it was called, but whether anyone has heard of any kind of damage that the thing would have prevented.

My gyro has the low one. I intend to put on the high one. The only question remaining is whether to take off the low one or leave it in place, and the only reason to do that would be if it's actually of use.
 

Brent Drake

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Yes it's a rock guard. For flying off unpaved runways. It keeps the prop from getting chipped.

Yes it does work as a HS. I have one with and one without. The (with) machine can't be turned as sharply and quickly. But the unstable effect allows this I presume.
 

Doug Riley

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Bensen ALWAYS referred to this device as a horizontal stabilizer. The "rock guard" nickname is a bit of a joke, started by people other than Bensen. Igor claimed to prefer that the HS not be too large or powerful, lest the aircraft tend to nose down in vertical descents. IOW, lest it be pitch stable. Heaven forbid.

The Bensen HS is too far aft to protect the prop very well. Some people, recognizing this, have installed wide strips of plywood on the bottom of the keel, all the way forward to the nose wheel, hoping to deflect stones thrown up by the nose wheel.

I've never known the Bensen HS to prevent prop damage, but how do you prove that something was trying to happen but didn't?
 

SMOF

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I've never known the Bensen HS to prevent prop damage, but how do you prove that something was trying to happen but didn't?

If people with only the high HS have had prop problems from rocks, that would be a good indicator, which is why I'm asking about it.

Also, does anyone have dimensions for a high stabilizer? The pics I've seen aren't a lot of help.
 

scottessex

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The best thing would be mudgaurds on the main wheels, since that is where the debris gets thrown up from.
At 1:10 in this video you can see the dew from the grass being thrown into the prop on the take off run
A rock gaurd would not help.
https://www.youtube.com/watch?v=khZyd_qm_jo
 

Doug Riley

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I had my share of pebble damage when flying with the stock Bensen H-stab, as well as without it. Some folks have used fenders on the mains, as Scott says.

I do think that the nosewheel shares the blame for debris in the prop.

A good area for the H-stab of a Bensen-size 1-place gyro is six square feet, assuming no radical HTL. This is big enough to allow the stab to do its routine tasks without having to assume large angles of attack.
 
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