Hang Test

[Alan Coats]

Well, I took my Bee to a friend's shop and did a hang test. His little shop has a 5 ton bridge crane, and enough head room to pick the gyro up directly off the trailer. Now I know what it feels like to be well hung.

Anyway, the previous owner had balanced the Bee for his weight, which is about 65 pounds more than mine (you don't look that heavy, Bob). The Bee hung 6 degrees nose down instead of the desired 10 degrees. The teeter bolt currently sits about 1" ahead of the front of the mast.

Can anyone calculate how far back I need to move the head to get the proper hang angle?

Thanks in advance,
Alan

[GyroRon]

Move the teeter bolt 1 inch for every degree you need to move. So for 4 more degrees the bolt needs to move 4 inches.

[Alan Coats]

Ron,

That would be too easy, because all I would have to do is reverse the cheek plates:)

Man, I'll be trying that right away!

Thanks (again),
Alan

[RICK MARTIN]

Ron, did you just make that up?

[GyroRon]

No! Maxie Wildes taught me that little bit of info. Worked for me everytime so far... Just ask Barry - Ultracrusier41 - Kroplien!

Alan try flipping the plates and let us know how it turns out.

[GyroRon]

Make sure your in the seat, with your helmet and all gear on board and with the control stick centered. Have someone look at the rotorhead to make sure your equal between the forward and rear stops! Also try it with a full tank of gas and empty tank and that will show you if you stay in limits.

[Brian Jackson]

That's great info Ron! I was theorizing ways to arrive at this on the CAD model, by scribing an arc centered at the CG that passes through the teeter bolt height and rotating the model -10 deg so that... blah, blah, blah. I trashed that idea... too many variables, mainly pilot weight and a million others. KISS and "real world" gravity are the only ways to be sure. But it does bring up one question: Since I'll be doing my rotorhead plates based on 155 lb. pilot weight, will other pilots whom weigh more have trouble test-flying my gyro?

Thanks,
Brian

[GyroRon]

Maybe yes... maybe no Brian. Best thing you could do is try to get it right for yourself and then add weight - put a bag of sand or fertilizer in the seat and sit on it - till your hang test goes out of the range. Whatever your maximum weight is before you leave the range would be the max pilot weight. Some gyros won't care if the pilot is 150 or 200 pounds. Others will go out of range with only a small change in weight.

You do bring up a good point though and that is to never fly a gyro that was not hang tested and adjusted for a person of simular weight to you. Brian you will be the oddman out since most people these days hover around 200 like myself.... Can I suggest starting with McGriddles, followed by a double Qarter pounder with cheese for lunch and for Dinner try the 20 piece Nuggets with BBQ sauce and a Milk Shake for desert. :)

[Brian Jackson]

Maybe yes... maybe no Brian. Best thing you could do is try to get it right for yourself and then add weight - put a bag of sand or fertilizer in the seat and sit on it - till your hang test goes out of the range. Whatever your maximum weight is before you leave the range would be the max pilot weight. Some gyros won't care if the pilot is 150 or 200 pounds. Others will go out of range with only a small change in weight.

You do bring up a good point though and that is to never fly a gyro that was not hang tested and adjusted for a person of simular weight to you.
Thank you, Ron. I'll be sure to pay special attention to that.

Brian you will be the oddman out since most people these days hover around 200 like myself.... Can I suggest starting with McGriddles, followed by a double Qarter pounder with cheese for lunch and for Dinner try the 20 piece Nuggets with BBQ sauce and a Milk Shake for desert. :)
Alright that's it :mad: . I've had it. Note to self: Never read this forum within a half-hour of eating because you may lose your dinner from involuntary laughter!!!

Damn you crack me up sometimes Ron! :D . I was all nice and mellow before reading that. Now there's gonna be a dry-cleaning bill. At least there were some big chunks that weren't half bad the second time... (eeeeew! That was crude even for me!)

On a lighter note, figuratively speaking, I'm trying to get down to my optimal weight of 145 by working out a bit in anticipation of flying QB. Shawn (a.k.a. Rotor-Head) mentioned a similar regimen he was on recently in another thread. Though not Jockey material, I'm a pretty small guy with a similar fondness for McGriddles and Chicken Nuggets :D whom could stand to be less attractive to gravity. (Man, I'm having scary visions now of Gravity Prison Bitches... sorry, it's late)

Anyway, thanks for that great bit of info and guidance. I wish there were an easier way to trim the CG such that other pilots could fly her. Perhaps there is... It ain't so much the weight but where it's located. If indeed a 200 lb. pilot throws it out of trim, could a small weight be attached near the tail (long moment arm) to compensate if it brings the craft within pitch limits of a heavier pilot?

Thanks immensely for your help!
Brian Jackson

[Ted Eggleston]

[QUOTE=Can I suggest starting with McGriddles, followed by a double Qarter pounder with cheese for lunch and for Dinner try the 20 piece Nuggets with BBQ sauce and a Milk Shake for desert. :)[/QUOTE]

and a plug Brian, you don't want to lose all that fat after going to all the effort of eating Ron's diet.... :D :D :D

Ted

[Brian Jackson]

and a plug Brian, you don't want to lose all that fat after going to all the effort of eating Ron's diet.... :D :D :D

Ted
Oh not you too, Ted! :D Actually a "plug" is something I wish I had... might help drain some of the grease I've ingested this winter.

[StanFoster]

Just to add my pennies worth....

After my RAF was finished.....I made a pivot block to go between my towers...and then used a sacrificial bolt for the hang test.

I got a loader tractor and picked it off the ground.

Now the RAF has four positions to set the mast. I hoped for one setting that would handle flying solo....and also handle hauling my 270 pound son as well.

My specs called for 5-7 degress nosedown solo...this is with 5 gallons of fuel. I got in...made sure everything was centered and had someone adjust my bubble level on the keel....and then hand it to me to read it. For redundancy...I would readjust the setting and have a different person do the same. I wanted to know for sure. The final reading was 5.50 degrees. So far so good. :)

Then my son climbed in and now the desired limits were 7 to 10 degrees nose down. It measured right at 9.25 degrees. I was elated that I could fly solo with my 220 pounds...and also take Jeff up with his 270 pounds and be in the required range....and do this without having to adjust my mast each time.

Of course...nothing proved it better than the actual flight......I have all the backstick I need for flaring when I have Jeff along.

Stan

[ultracruiser41]

Hey Brian,

Ron's absolutly right...sometimes, flipping the cheekplates work if you only need a few inches....as for the pilot weights......

it is difficult to get a large pilot weight range for certain gyros....that's why I had to "bulk up" to Ron's weight since he test flew my Bee !!! :eek:

I was a trim 135 pounds until I went on Ron's McGriddle Diet and now I am a very sexy 200 !!!! :p Gyro fries as stable as a rock now....doesn't climb too well for some reason though :confused: (just kiddin)


BarryK

[Timchick]

Brian, Don't let these big boys intimidate you. I'm right around your weight. I'm sure we'll be getting better performance out of our gyros.

[REDHORSE556CES]

Maybe yes... maybe no Brian. Best thing you could do is try to get it right for yourself and then add weight - put a bag of sand or fertilizer in the seat and sit on it - till your hang test goes out of the range. Whatever your maximum weight is before you leave the range would be the max pilot weight. Some gyros won't care if the pilot is 150 or 200 pounds. Others will go out of range with only a small change in weight.

You do bring up a good point though and that is to never fly a gyro that was not hang tested and adjusted for a person of simular weight to you. Brian you will be the oddman out since most people these days hover around 200 like myself.... Can I suggest starting with McGriddles, followed by a double Qarter pounder with cheese for lunch and for Dinner try the 20 piece Nuggets with BBQ sauce and a Milk Shake for desert. :)


Hmmmmmm........sounds like the Homer Simpson diet. LOL!

[Brian Jackson]

...Gyro fries as stable as a rock now....
BarryK
A Freudian slip? LMAO! :D

[Dean_Dolph]

...... I wish there were an easier way to trim the CG such that other pilots could fly her. Perhaps there is... It ain't so much the weight but where it's located. If indeed a 200 lb. pilot throws it out of trim, could a small weight be attached near the tail (long moment arm) to compensate if it brings the craft within pitch limits of a heavier pilot?...Well, there might be a way to ground adjust for this.

Anthony Spagnoletti developed ground adjustable cheek plates to go with his single place to two-place sxs conversion setup on his Air Command. Another local gyro builder duplicated his effort but that gyro has never flown. I have some pictures but unfortunately my computer is being obstinate and is refusing to read the zip drive so I can't post them. I would bet others have made permanently mounted adjustable plates.

[Doug Riley]

A bit of 'Bee trivia: Ralph's hang specs are at the tail-heavy end of "normal" for a gyro. He tells you this in the manual, but it's easy to miss. 10 deg. nose-down on a 'Bee translates to -1 at the mast on a Bensen. The middle of the Bensen range is -2.5 at the mast (which translated back into 'Bee-ish is -11.5 at either the keel or the mast).

What all this means is that you should err on the side of "nose-downness" on a 'Bee, if you must err at all. If you light guys set yours up for -10, your machine will be OK for at least a couple dozen more pounds, probably more.

[Alan Coats]

Doug,

Maybe I am not understanding correctly, but my 'Bee documentation says "If you are willing to settle for a degree or so of error, it should be off on the nose high side, not nose low."

That quote is from the "Setting Up Your Rotor Head System" section on page 108.

Am I missing something? Please explain further.

Thanks, I appreciate everyone's input.
Alan

[Doug Riley]

I'll let Ralph respond to clarify his position. Elsewhere in the documentation, Ralph states that his specs produce an intentionally nose-high flight stance. I've found that to be the case in fact.

The Bensen specs produced a pretty keel-level flight stance.

[Alan Coats]

Doug,

I remember reading that on Ralph's site. He said it made for a secure feeling while you were flying - didn't feel like you were going to fall out of the seat. I've also read, though, that the Gyrobee takes off and lands in a relatively flat stance.

Alan

[Doug Riley]

My experience is that the 'Bee will leap off at about 18 mph, very nose-high, unless it gets a healthy dose of forward stick (see photo of a slowish takeoff). If you do add the stick, it will lift indeed off fairly flat at 25 or so. The flat stance results partly from the fact that the tailwheel has only about 3" of ground clearance. 6" - 8" is common on other Bensen-style gyros.

The HS down-load plays into this. Ideally, the HS should have sufficient down-load to offset completely the nose-down effects of any high thrustline. The result, however, is a force at the tail that, once the machine is moving, acts like extra weight back there. This lead to a more nose-high flight stance than you'd otherwise have. The solution is NOT to reduce the HS incidence (the HS is doing what it's supposed to do) but to change the hang specs.

All this argues for a hang spec closer to 11 degrees than to 9.

[Alan Coats]

Using Ron's 1" per 1 degree rule of thumb as a guide, I made some temporary cheek plates, with adjustment slots. I was able to get a good hang test with the temporary cheek plates, but had to slide the head all the way to the end of the slots.

After all was said and done I had changed the hang angle by 3.5 degrees, and had moved the head back 4 5/8". That equals just over 3/4 of a degree per inch of change. I would guess that on a gyro with a shorter mast the change would be closer to one degree per inch.

Below is a picture of the not-so-pretty, but functional, cheek plates.

I made new cheek plates, installed them, and mounted the head. Then I discovered that the control rods are going to hit the fan shroud on the engine. Now I'll be making scissor arms for the control rods.

Alan

[Doug Riley]

Pushrod interference seems to be a common experience for 'Bee builders. There are many 'Bees with control "scissors" installed.