Building Mariah Gale

Vance

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I like big tails.

I like big tails.

Thank you for your input Roger,

We have thought about some sort of fences because of the high aspect ratio of the horizontal stabilizer.

At this time we feel we have adequate empennage volume and we would rather not have the extra drag.

The vertical stabilizer volume is approximately 53 square feet and the rudder volume is approximately 34.3 square feet.

The horizontal stabilizer volume is approximately 145 square feet.

We can always add something later if we find out she is wanting for control or stability.

Our current thinking is a ground adjustable horizontal stabilizer unless we find there is value in an in flight adjustable horizontal stabilizer and we have left some provisions for that.

Thank you, Vance
 

SgurlEd

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Ask Vance's log book

JEFF TIPTON

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Geez ED, I thought you said a few. Hate to think what a bunch would be. Pictures look good and am glad you are getting back in the saddle for fun.
 

RotoPlane

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Thank you for your input Roger,

We have thought about some sort of fences because of the high aspect ratio of the horizontal stabilizer.

At this time we feel we have adequate empennage volume and we would rather not have the extra drag.

The vertical stabilizer volume is approximately 53 square feet and the rudder volume is approximately 34.3 square feet.

The horizontal stabilizer volume is approximately 145 square feet.

We can always add something later if we find out she is wanting for control or stability.

Our current thinking is a ground adjustable horizontal stabilizer unless we find there is value in an in flight adjustable horizontal stabilizer and we have left some provisions for that.

Thank you, Vance
I've tried to understand your stabilizer "volume" numbers Vance....but have given up. Perhaps when you have time you'll enlighten me.....? I'm missing something....
 

Vance

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Hello Ed,

I am trying to use Ed's tablet and it is not working for me.

Volume is the area times the moment arm.

That is why the numbers are approximat, I don't know where the center of gravity will be.

It is just a guess at this point.

Thank you, Vance
 

Riff Raf

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I've tried to understand your stabilizer "volume" numbers Vance....but have given up. Perhaps when you have time you'll enlighten me.....? I'm missing something....
Same here.

also, what does an adjustable HS have to do with yaw?
 

Vance

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Hello Roger,

An adjustable horizontal stabilizer has to do with what we are doing with the empenage and nothing to do with yaw.

We do not imagine we will have a problem with yaw because of our large vertical stabilizer, large rudder and generous moment arm.

Thank you, Vance
 

Resasi

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Vance possibly my turn to be 'dippy' but as I understood it high aspect ratio means long and slender. Your HS seems to me to be low aspect ratio ie short and broad.

I do realize that the last thing anyone wants is a massive peacock type tail hanging of the back of your bird, but in compensation you will at least have a long arm.

I like the idea of a trimmable tail as in the Mooney where you can vary the angle of attack of the empenage.

I too thought of flat plates on the ends of the HS as I looked at it, not sure quite why, increased yaw stability perhaps, then reflected that they are not as elegant though as Whitcomb winglets. The height of your fin would seem to indicate plenty of stability anyway, but somehow I felt the HS seemed a bit stubby.

Just musing.
 

Vance

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I stand corrected

I stand corrected

Thank you for the correction Leigh.

Most who have looked at the empenage feel it is way too big for a gyroplane.
We are looking for a very stable airframe that is controlable in gusting winds so we went with the big tail.

When we are on our trip I won't have the knoledge of the weather that I do around here so I may get caught in big winds.

We moved the empenage forward six inches when we raised it to keep the mast from getting too tall and raising the vertical center of gravity.

The reason I am using Ed's tablet is because we flew to Santa Paula last night for the Camarillo Air show. This is signifigant because the flight returning from the air show last year was Ed's first panic attack. It was gusting 25kts over the San Marcos Pass with some verticals in the 1,100 foot range. So far so good, she says she is havving fun.

Thank you, Vance
 

Vance

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A conundrum resolved.

A conundrum resolved.

The plan was to put the bolt on semi finished keel in Vince’s hands so he could manage the mounts for the empennage and then send the completed tail back to Jim so he could finish the keel. This was in retrospect not best practice.

Jim balked at building a keel that had a temporary finish on it so that Vince could manage the mounts.

This was my suggestion because it seemed like a good way to move forward.

Jim is fussy about load paths and as he got closer to finishing the design of the keel he became concerned about the lacing for the truss being in the right place. I am grateful for his resolve.

Vince couldn’t make the mounts until he knew where the keel ended.

I knew it was time for me to have some face to face with Vince and Mike so I had the M Roadster serviced, packed my bag for a couple of days and prepared to leave for Hollister the morning at O’dark hundred the next morning. I gave Vince a call to make sure he could make time for me. I had no clear goal in mind or even a path to progress and therefore didn’t know how long it would take.

It was still dark when I began to get ready to leave. I checked the weather and found it was already VFR at SMX so I packed everything in a different suitcase and headed for the airport.

The sun was just coming up as I performed a thorough preflight. I added a quart of oil and filled out the engine log book.

It was still a little cold so I put on a sweat shirt beneath my flight suit.

I called Lockheed Martin for a flight from SMX to CVH and there was an AIRMET for low ceilings and mountain obscuration. I called the SBP ATIS, checked PRB’s ASOS and Checked the SNS ATIS. SNS was IFR but everything else looked good.

The Predator burst to life with just a touch of the button and settled down to an even idle. She seemed excited and ready for adventure. I called ground with Juliette and was to taxi to runway 30 via Alpha.

The run up went well and I runway 30 was clear for takeoff with a straight out departure.

She leapt into the air and climbed out quickly in the cool dense air. I pulled her back to 2,300 rpm and 65kts and she continued to climb. We hit an inversion at 2,000 feet and it was suddenly a warm summer day.

Ten Miles South East of SBP at 3,000 feet MSL I asked ATC for an overhead transition to the North West. It was approved as requested. I played a little dodgem with one aircraft not on frequency and was soon over the pass and began my descent. It was a perfect day to fly with just enough turbulence to romance the wind.

The morning light made the hills come alive with shadows as we followed the river North West toward King City past the Hunter Legit MOA.

We had been rumbling along at 65kts indicated air speed showing 78kts of ground speed on the GPS. As we descended there was a wind shear at 1,800 feet MSL and the wind changed direction 180 degrees and became a slight head wind. We climbed back up to 2,000 feet MSL as King City (KIC) came into view.

There was no one in the pattern so we made a left base entry for runway 29.

A third of the way down the runway the wind shifted again and we overshot the midfield taxiway. I put the power back in because it was quite a way to the next taxiway. The touchdown was nice and I waved at my friends as I taxied to fuel.

A quick visit to the empty pilot’s lounge and we were airborne again and looking for my valley that goes all the way to Hollister. The hills were rugged and imposing but we were soon invited into the lush valley.

In about 40 minutes of particularly lovely flying Hollister came into view. The Hollister airport (CVH) is on the far side of town. As we descended through the wind shear the wind again changed to a slight quartering head wind. As the airport came into view the tetrahedron couldn’t quite make up its mind so we made a base entry for runway 31 and landed with a bit of a crosswind at the taxiway before the crosswind runway.

We taxied to transient parking, tied her down and stowed our gear at Galivan Aviation and headed toward Corbin Saddle.

Vince was not hard to find and we began to work on a drawing to send Jim. Mike joined us and came up with a mounting plate concept. As we struggled with the structural details and the attachment scheme Vince sort of lit up and said “let me take a splash from the mold of the part where the mount goes and send it to Jim and with the spars and ribs drawn in and he can make a plate, mount it to the keel and send it back.”

This is a great solution because it leaves the fabrication in the hands of the people who are best equipped to handle that particular material.

I called Jim and he said it was “better than I had hoped for.”

Things can be a little touchy when you are mixing artists that are doing it for the art.

Vince is going to make it happen as soon as possible.

Pleased with the results and feeling on a roll I went to visit the airport manager and propose flying in the Hollister Air Show. He asked for some material to show to the rest of the decision makers and we discussed my inability to receive compensation until I get my commercial and what it would take to manage the local FSDO. I left there quite pleased with the way the day was going with a lovely flight home ahead of me. I had a nice brunch at the Din a Ling café, picked up my gear and gassed her up.

The tetrahedron had made up its mind and we took off from runway 24 with a left crosswind departure to the South East. I stayed low all the way to Paso Robles to keep the 8kt tail wind.

Mission accomplished.

Thank you, Vance
 

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Vance

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A little more progress.

A little more progress.

Thank you Mark,

I loved the flight. It is prettier in the winter when the hills are a lush green and the river rushes swift and deep.

Here are a few pictures of the flight back and a short story of more progress


We climbed over the town and headed toward the little valley.

I played motorcycle staying low over the road and caressing her curves and ran her up down the long straights.

The farm lands gave way to short pine trees and then rolling hills.

It was not hard to get off track as we bobbed and weaved along the valley.


I was in the right place emotionally and overflowing with flying passion.

Every now and then we would get up into the sheer and it would get very confused and a little bumpy.

The low tail wind stayed with us all the way to Paso Robles.

We stopped in Paso Robles and the temperature had climbed to almost 100 degrees F.

As I filled her up a nice gentleman from Scotland came up with an earnest young man and offered us refuge from the heat and a free cold drink.

There was something special about this Scott and I took him up on his offer. He was partners in the FBO and although he had lived in New York for 25 years there was no question about his homeland.

I got to talking about my need for instrument training to get my commercial rating and he mentioned that his partner was a CFII in helicopters and fixed wings. He teaches in a Bell 47.

When his partner showed up we went through the FAR/AIM to find the requirements for Commercial Gyroplane. “We can manage that!” he said without hesitation and gave me a reading assignment.

I was on a roll and this had become a very productive day.

The flight back to SMX was icing on the cake.

The flight was 325 nautical miles at an average of 63kts with a top speed of 99kts.

It was a lovely day of flying.

Thank you, Vance
 

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gyrojake

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Well done Vance. Everything looks great.
Your an inspiration.
Can't wait to see her all together.Well thought out and unique.
Love the tail section.

~~JAKE~~
 

Vance

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Resolved conundrum.

Resolved conundrum.

Thank you Jake,

I wish you were more involved.

More than once I have asked; “how would Jake do it?”

Your solutions are so simple and elegant.

I am headed up to Greenwood the middle of next week.

We seemed to have resolved the “which comes first the empennage or the keel” conundrum.

Vince sent Jim a splash off the mold with the spars and ribs simulated and we feel we have a plan for the mount and the finish for the keel.

In a perfect world I will take the empennage mount back to Vince and we will have a finished empennage before we build the rear suspension so we can make a better guess on the CG.

Thank you, Vance
 

Vance

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An iterative conundrum!

An iterative conundrum!

My fantasy of taking the empennage parts to Vince didn’t come to fruition.

We keep thinking that we have the answer and then we don’t like it for some reason or come up with a better scheme.

Exactly how the empennage mounts has been an ongoing challenge. It is not that we can’t figure out how to do it. The challenge is we have different disciplines working on it and the one group is often not entirely comfortable with what the other group comes up with.

Fiberglass guys, Vince and Mike are concerned with the interface between the fiberglass and the metal because they don’t want the metal to cause the fiberglass to fail.

The metal guys, Jim and Vance are concerned with stress risers further up the keel. The truss needs to develop itself so that it doesn’t’ fatigue and break somewhere considerably removed from the empennage.

To make matters worse the metal guys are not exactly aligned with the termination of the keel.

Vince took a splash of the empennage where it attaches to the keel and with the ribs simulated and Jim is going to make something and attach it to the part and send it back to Vince.

We have all thought we have put this to bed several times and sometimes been excited about the plan.

Then somewhere in the night we find a reason that is not what we want.

The metal guys are in agreement now although it took a change of hardware when I got back because Jim was not satisfied with the secondary form of retention.

Jim hopes to have something done by the beginning of next week and send the assembly down to Vince.

He is making the plates out of stainless steel.

Hopefully Vince and Mike will approve.

Jim has two new restoration projects in his garage.

One belongs to Walt Fulton, ex factory road racer and the Harley Davidson factory gave it to him when they came out with the XR.

The other one is the KRTT that Calvin Rayborn one Daytona with twice, the second time lapping everyone but second place. This is a particularly famous motorcycle.

It is also a bike I finished second in the Battle of the Twins with at the Riverside national in the early 80s. I loved the way she handled, I could slide her around on the pavement in a very controled way.

I finished ahead of a lot of much more exotic machinery and we ran it without the fairing. I broke the brake cable on the 5th lap and would draft the Ducatis down the straight and then pass them into the corners because I had no front brake. They started giving me a lot of room after a few times of that.

On the last lap I passed second place when he used the racing line out of the banking and I took the short line. It meant I picked up 50 feet but was out of control in turn one. The look on the Ducati riders face when he realized what was passing him was priceless and one of my favorite racing memories. The thought of a flat head from 1966 passing a state of the art desmodronic Italian wonder caused him to question his reality and it was written across his face.

Harley Davidson never gave me the money they promised because they felt we were not serious enough.

I gave them my very best serious look but they were unmoved.

Jim is restoring them for two different owners. Walt’s bike is unmolested but less valuable. Jim will use it as a model to restore the more valuable bike to the way it was when it won Daytona. It has been through several owners and modified in inappropriate ways. Walt still owns his and Jim is restoring it for him.

Sorry to digress but Jim and I had a lot of chuckles when we figured out the history of the bike. It is a small world.

I left Georgetown at 0'dark hundred and we ran into more clouds on the way from Georgetown to Rio Vista, yikes!

Thank you, Vance
 

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choppergabor

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Fascinating how much planning and research is going into something as simple like the empennage that people will look at after it's done and say "what was the big deal about that"? I personally feel your pain as for making sure the stress points won't fail and no fiberglass and metal interaction will ruin the creation. Lots of planning that an outsider doesn't really understand unless if they created something. I do admire the amount of work you guys pit into this :) Hats off to you all!
 

JEFF TIPTON

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Vance; would I be correct in that, the rod ends are the attach points for the tail assembly?
 

Vance

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The devil is in the details.

The devil is in the details.

Thank you Gabor,

We are all trying to not do anything that is going to be a problem and our ignorance haunts us.

We are trying to mount something kind of heavy out on the end of a long stick and we don’t want to make the long stick heavy.

To complicate matters the stick has to go around a corner.

We feel that we don’t know enough to predict the frequencies or amplitudes of the perturbations because we don’t know how our rotor mounting system will work.

We are trying to manage the competing goals of strength and light weight with low drag thrown it to confuse us on a higher level.

Our primary discussion this time centered on adjustability. Jim wanted to pivot the empennage at the 25% chord line of the horizontal stabilizer and make the back screw adjustable because he imagines a regimen of testing more complex than I do. I like spacers of different lengths which require more fabrication but I feel is simpler and stronger.

In my fantasy we try neutral and four degrees nose down to start with and determine what effect that has on the way she flies. I hope the results of the testing are clear enough to where we will only have to make one more set of spacers. At this time they are a short piece of aero tubing with a 5/16 bolt sandwiching the plastic between a bonded in nut plate and an outside plate attached to the tubing. Each test angle will require four carefully made spacers so the angles come out right. The size of the nut plates is also one of our points of controversy.

Part of what confuses the test process for me is the ability to move the rotor head which does a similar thing in a different way that operates over different speed ranges. The rotor thrust vector changing with speed adds another variable. We are trying to operate over a wider speed range than most gyroplanes.

It is hard to know how much drag the higher speed gyroplanes are giving up to manage the angle of attack of the fuselage. We are hoping to minimize some of the compromises I have experienced in the faster gyroplanes I have flown. Because Mariah Gale will be open her angle of attack will affect the drag more than an enclosed aircraft.

We are not doing well with low drag in the keel because of the bolt head out the bottom and the right angles between the spacer and the bottom of the horizontal stabilizer. Once we know the angle we want the horizontal stabilizer to be we can build the streamlining into the bottom of the stabilizer.

The cross pieces for the truss will all be aerodynamic tubing but the keel is still draggy. We feel that it is still at least 30% less drag than The Predator’s keel and that is one of our design criteria for the details.

We all want to make her the best she can be and it is hard to stand back and say that is good enough.


Hello Jeff,

At this time we feel the spherical rod ends are for mockup purposes and the finish will not be adjustable. There is no reason to pivot at that point because there are four attachment points that will prevent pivoting. Adjustability there would allow us to make room for a larger propeller but that sort of changes everything else if it is a substantial amount. On the other hand they are readymade and strong.

I feel we would just build a different keel if we wanted to use a much bigger propeller which of course would affect the length of the suspension and the height of the rotor.

Thank you, Vance
 
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Vance

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Mitigating trepidation over tail weight.

Mitigating trepidation over tail weight.

One of the fears we had about Mariah Gale was put to rest today.

On my last flight to Georgetown in the Predator; the bracket that mounts the upper vertical stabilizer support broke for the third time and I decided that we needed to modify the design so we began to remove the vertical stabilizer and rudder.

The vertical stabilizer has two sockets that male tubes fit into and they were rusted tight.

A lot of persuading over a day and a half to let the oil soak in was unsuccessful at sliding the tubes out of the socket so we sawed off the rear one and still twisted the front one to remove it. I fear that the fabrication will damage the cover so it is time to recover. I pulled off the Horizontal Stabilizer too and weighed everything.

The vertical stabilizer and upper support weighed twelve and a half pounds. The rudder weighed three and a half pounds. The horizontal stabilizer weighed 10 pounds.

I was concerned that the tube and fabric empennage on the Predator was much lighter than the 31 pounds we imagine for Mariah Gale’s empennage.

We will see how much the empennage ends up weighing. If it is only 5 pounds I am happy to pay that for the airfoil shape that hopefully will cause less drag and a smoother lift curve with a little more rudder authority.

We feel the keel will be close to 10 pounds lighter so it may all be a push.

Guessing where to put the mains will be much easier if the empennage does come out at the target weight.

She looks kind of naked without her tail feathers.

I talked to Jim today and he felt he will be able to ship out the mock up empennage on Monday or Tuesday so Vince should have it by Thursday, October 20.

Thank you, Vance
 

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