gyro hang test question

taint

Newbie
does anyone have a picture of them doing a hang test on there gyro? i would like to see them. thanks taint
 
Tiant, The way to hang test you Gyrocopter is to hang it by the rotor head teeter bolt and make sure your rotor head and mast are at a 90 degrees you gyro should hang at 2 degrees nose down. If you would like pictures then email me at [email protected] and i will send you some pictures.
 

Caribean_gyro

Platinum Member
you have to make a 'V" in steel weld it to a bushing and feed the teeter blot thru it. dont scratch ot hang it direct to the bolt
 

scottessex

Sling-Wing Pilot
I welded tang to a piece of 3/8" I.D. steel tubing and run a shackle through it and hang it from the shackle.
 

jcarleto

Aluminum Supporter
Make sure to center the cyclic when you do your test. One good way to make sure it is centered is to make wooden jam blocks and block the torque tube exactly even between the fore and aft stops.
 

NoWingsAttached

Unobtainium Member
I'm glad you asked.

WHat? Scott, Jon, have you forgotten everything I've taught you already? Here it is, step-by-step, photo-by-photo.

First, fill up the gas tanks full, grab all your gear you plan to wear flying, and let's get going.

1. Find a cute little 20-somethings girl and hook up with her for a year or two. Stick her in the front seat. Take pictures. Lots and lots of pictures. It helps if you are disgustingly old, like you should be in your 50's. This drives people absolutely nuts, and you'll enjoy the hell out of it.

1a. So I added the close-up, just to make sure you fully appreciated the gyrotor hang test model.

2. Find a contraption to lift the gyro off the ground. Your local telecom company cable yard fork lift truck will work nicely.

3. Stick ANY old bolt through the teeter blocks that'll fit. The other guys are right, you probably shouldn't use the bolt you intend to fly with, but you don't need to get fancy. Welding tang onto it? C'mon, I thought that was what the astronauts drank in space, Scott. hehee, couldn't help myself.

4. Replace the cute, leggy female with your sour old ass. Hang a plumb bob from the same point you attach to, first the teeter bolt. I have enhanced the string in the photo so it is easy to see.

5. Next, hang the gyrotor from a second position, as seen here. Hang the plumb line from this position as well. I have also enhanced this photo for illustrative purposes.

6. Juxtapose the two photos one over the other with some photoshop software, and where the two plumb lines intersect you have your REAL center of gravity! THis is what REALLY matters. Now you need to line up your thrust line through the center of the prop and measure how far off it is from the COG. This machine is pretty much dead nuts, not more than 1/2-inch off. It doesn't get much better than this.

As for your HANG ANGLE, well, I don't know about any such universal numbers for all gyros like 2 degrees, but I do know that Air Command recommends for THIS machine anywhere between 1 to 4 degrees from vertical is acceptable. As shown, this machine is nicely within that spread.

If you doubt my word, go back to photos 1 and 1a. I think you'll begin to see the wisdom of my ways. I may be crazy, but I sure have more fun than sane people.
 

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quoj

Newbie
On that subject, I have an couple of annoying newbie questions:

How often should one hang one's machine?

I understand it all depends on weight.
So, if you're increasingly suffering from "middle-age spread" or hitting the gym whilst doing the Jenny Craig thing, and so changing your weight significantly, you're going to change the overall balance with respect to C of G.
Is that correct?

Is there a ball-park change in weight of maximum all-up takeoff weight that would necessitate a re-hanging?

Also, does that mean that your average Bensen/Brock-style gyro is very-much a "one machine, one person" type setup?
i.e. it is "calibrated" (for want of a better word!) to suit one particular pilot/weight range/etc and so cannot be used by two people of significantly differing weights?
If so, can it be calibrated for the heavier of the two, and then ballast (like you'd place in a glider/sailplane) be added for the lighter pilot?

And then how does that work for 2-seat machines where it may be flown solo one day and dual (with some random person of a random weight) another day?

Thanks in advance.
 

quoj

Newbie
Thanks, S. Craft.
I'm not sure what I'm supposed to be looking at on the third picture down... or how this answers my questions?

Thank you.
 

GyroCraft

Member
Taint started this thread by asking for a picture of a hang test. There is one on the link I supplied. Granted, "No Wings Attached" posted better pics.
 

quoj

Newbie
No worries.

Well, then can anyone else answer my questions?

I want to build a gyro but may share it with a mate who is vastly different in build/weight to myself. (i.e. 100 pounds different!!)

I am curious as to how to do that with one, simple CLT, open-frame single-seat machine.

And if I were to later on buy a two-seat (probably side-by-side) how do you hang that to account for all uses?

Thanks in advance.
 
Its possible to have the heavy pilot at the nose down limit and you at the nose up limit. However with 100 pounds difference, you will probably fly with ballast added to keep both of you in the CG range. Stani
 

quoj

Newbie
Thanks, Stan.
I've done a fair bit of sailplane flying and ballast is used all the time with them.
I wasn't sure if ballast was common in gyros.

So, how do you hang a side-by-side two-seater which may have varying pilots of varying weights and with two pilots one day, and one the other?
 

Vance

Gyroplane CFI
My hang test opinion.

My hang test opinion.

Hello Lincoln,

I was taught that once you determine the CG limits you do a simple weight and balance calculation to see what the change is with variable loads.

I feel part of the reason for a hang test is to see that the controls have enough range to handle the hang angle and still flair.

I am flying a two place tandem that has both the fuel and rear seat passenger slightly ahead of the center of gravity.

We hung her with what we felt was a good range of pilot, passenger and fuel loads to verify our calculations. I have gone from no one in the back seat and 18 pounds of fuel to 280 pounds in the back seat and 132 pounds of fuel without going outside her CG range.

The pilot is well ahead of the center of gravity so he has a much longer moment arm. I have had a pilot as light as 160 pounds in the front seat and as heavy as 250 pounds.

If I am flying someone very heavy I can carry less fuel to keep from going outside what we feel is her CG range.

We have not hung her in 700 hours and three years with a 40 pound change in pilot weight because we can do simple weight and balance calculations. She is not close to the edge of the CG range. I keep a bathroom scale in the hangar to manage passenger weight reporting errors.

In the USA part of the operating limitations that must be carried in the aircraft is weight and balance and CG limits.

On a light solo machine I feel you could manage extreme pilot weight differences simply by changing the location of the rotor head.

Some tandems I have seen have a movable rotor head for just this reason.

In my opinion how sensitive the machine is to variable load changes depends on the design of the machine.

Thank you, Vance
 

quoj

Newbie
Thanks, Vance.
They are good and comprehensive answers to my questions!

At this time, I weigh 187 pounds, but my mate weighs 286 pounds.

I would be the main pilot, but if he were to fly, then I'd probably need to make some decent changes.

The rotorhead idea sounds promising, rather that having to constantly fly about with 100 pounds of ballast so that if he chooses to fly, I can take it out!

Many thanks.
 

Caribean_gyro

Platinum Member
I agree with vance and stan, first tell you mate to loose weight good for his health. the adjust the machine for a nose down of 7 degrees max. with him on board. I figure that with you it should be around 2 degrees. Now letting another person fly you gyro is like letting your wife ride a bike with the neightboor!!.

Partnership in gyro I have not seen it work right. wish you well.
ChuckP
 

Caribean_gyro

Platinum Member
hang test

hang test

I agree with vance and stan, first tell you mate to loose weight good for his health. the adjust the machine for a nose down of 7 degrees max. with him on board. I figure that with you it should be around 2 degrees. Now letting another person fly you gyro is like letting your wife ride a bike with the neightboor!!.

Partnership in gyro I have not seen it work right. wish you well.
ChuckP
 

quoj

Newbie
Yes, well I guess that both our sorry old carcasses could stand to lose a few!
:lol:

As for partnerships, I would only offer it as he is offering to help build it.
But that's probably good advice to not share a gyro, so I'll definitely take it into consideration.
 

Lee Scatt

Crash-test pilot
Thanks, Vance.
They are good and comprehensive answers to my questions!

At this time, I weigh 187 pounds, but my mate weighs 286 pounds.

I would be the main pilot, but if he were to fly, then I'd probably need to make some decent changes.

The rotorhead idea sounds promising, rather that having to constantly fly about with 100 pounds of ballast so that if he chooses to fly, I can take it out!

Many thanks.
My Dad and I both flew the same gyro for a few years. I was about 285 and he was about 180. I can't recall the numbers, but it hung within range with either of us in the seat.
We built an in flight adjustable trim spring, it trimmed out nicely for both of us.
It was a Bensen style.
 
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