Building Mariah Gale

Vance

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Colnfused on a higher level

Colnfused on a higher level

Thank you Gabor,

I am delighted you enjoy the thread; I wish you were here to make fun of her as she comes together.

I like the way India looks better too. Now in my opinion all three of her legs are similar rather than looking like her back legs were broken.

It appears to me that the India main gear is lighter, simpler and stronger.

The interface between the axel/caliper is more difficult to fabricate and will use an aluminum axel.

The links will be sheet steel and tapered in two directions. We want a radius on the corners so we will send it out to a fellow in Grass Valley, just up the road from Greenwood.

The pivot bearings will be high molecular weight plastic and split to aid assembly.

We have two different schemes to control the roll resistance and at this time it uses two smallish, long coil over dampers.

The legs will be made from the same Aluminum strut material that the front suspension is made from and have a straight link out of smaller aluminum streamline near the bottom between the adapter plates. India should be about 2/3 the weight of Charlie.

The old keel we are scrapping is about six weeks of work.

I like the looks of the new keel with its graceful bend and more gentle angles. I feel the air will like it better too.

I did my weight calculations for the keel again this morning and the main tubes (7/8 .049 wall) for the keel should weigh less than 6 pounds.

We are using 7/8 .049 wall 4130 for the four main keel tubes because that is what Jim has the most bending dies for.

The lower tubes have a larger radius than the upper tubes.

The lacing is half inch .049 wall except the pieces that are directly across and they will be smallish .049 streamline tubing so it might account for another two pounds.

The reinforcement at the bend will be .040 sheet. It should weigh less than a pound.

It appears that the weight of the assembly is less than half the weight of the old keel and attaching bridge.

We are intentionally making it more flexible in bending and stiffer in torsion.

The picture is of the old keel without the attaching bridge that we are scrapping.


Hello Jeff,

I am glad you asked because I find value in trying to explain it.

I believe you are correct.

My cad program is still crippled.

I made a very rough doodle of the new keel and then made it worse by converting it to jpeg.

The upper tube of the keel on each side will attach to the frame just below the upper engine mount.

The lower tube will attach to the back of the lowest part of the frame.

They are converging horizontally throughout their length.

They will still have considerable horizontal separation as they pass under the propeller and some vertical separation to get some beam strength.

We feel the vertical week point of the truss is under the propeller because the tubes are close to parallel vertically after they pass the propeller so we will have a gusset plate with fish mouths to spread the load.

The new scheme for mounting the empennage is to come out through the bottom of the horizontal stabilizer with some plates that go directly to the spars rather than notching the spars and having a right angle box like we have now.

Because the tubes are splayed wider horizontally the loading is less localized.

The drawing is made from one of the earliest versions of the suspension in the flight position so the arms are not yet tapered and the pickup points are not yet located. There will probably be a coil over dampener on each side outside the frame but inside the body. The will be driven by an arm like the ones to the struts but at a different angle off of the lower link. All the attachment and stress points sort of fell into place as we handled the metal.

You can see why Jim was confused when I tried to describe it.

Thank you, Vance
 

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Vance

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A little before and after.

A little before and after.

I have added a very rough doodle of the old attachment scheme for the keel.

There would be considerable truss lacing.

The suspension shown had main gear arms almost parallel with the earth that and are not shown in the drawing. The tube shown in the drawing is the push rod that operates the linkage to the shock and manages the roll resistance. It would have been made with streamline tubing.

We felt one of the challenges was that keel was too strong so we needed to widen its attachment points or we would have created a stress riser.

The Predator is showing some signs of unhappiness in this area.

When we made things more parallel we had to increase the cross bracing.

The two vertical tubes and the cross tubes were to be streamlined tubing and the rest was to be round tubing.

We both liked the keel but had reservations about the interface between the main structure and the keel.

Once the keel was braced we realized we could have used much smaller lighter tubing. We simply had copied the Predator but didn’t to copy the interface because we felt it was dirty aerodynamically and localized the stress.

The heavier empennage and longer arm exacerbates everything.

Thank you, Vance
 

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SgurlEd

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Little Miss Indy! I like it ;-P

Little Miss Indy! I like it ;-P

Jim’s attitude was sorely tested Tuesday morning and today, Thursday. He did well.



That changed Tuesday morning.

Somewhere in the night of July 12 the answer came to me as to how to use something much closer to the original main gear design.

I spent the rest of the night until the early morning light trying to figure out what was wrong with what seemed a simple solution.

If it doesn’t make sense to you don’t feel bad, so far Jim and I are the only ones that embrace it.

Ed kind of likes the way it looks compared to the other design.

Thank you, Vance
Somewhere in the night...??? It's about 10:30pm I'm sound asleep in the Media Room and Vance comes in and says "Let's go to bed Sweetheart"...Ok...I get up I get in the bed I quickly fall asleep (I'm trying to adjust to some new heart medication and other drugs the Doc has given me so I tend to fall asleep at the drop of a hat) not but about 45 minutes later...there's no Vance in the bed??

Wait wasn't he just here didn't HE just wake me up so WE could got to bed together? What the???

Ok...he's probably just forgot something and need to makes some quick notes yeah... that's it Ed just a couple of notes and he'll be back in the bed riiiiggghhhht.....NOT 3 1/2 hours go by3:30am he gets back in the bed.

I don't say anything just lay there watching him he is laying on his back I swear he's not saying a word but I heard the gears grinding away...he has his hand on his chin rubbing it then tapping his finger as if he's had another idea....about 45 minutes later he's back up again I didn't see him again until he came back into the bed at 5:30 and he was very excited I could tell and finally I asked what the heck he was up to...well you all know the rest of the story.

Seems like a painful but necessary process for Vance. Usually the ending results are always something truly amazing so I can't be too upset or jealous over the creating of Mariah Gale. I do think however think I'm gonna start calling her Indy for short because I feel she gonna be as adventurous as he Daddy Vance!

Vance is right I really do like the design but that also means I have to alter all my drawings of "Indy" because the dynamics have changed quite a bit, but as he said it's all for the better...and I'm only a little Cog in this big Adventure but I do love being a part of it!!

Cheers to all! TGIF...I'm off to see Happy Potter tonight Woo Hoo! ♥Ed♥
 

JEFF TIPTON

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Vance I was wondering if you had considered bolting the rear assembly on instead of welding. I am thinking it would be easier to repair or replace if necessary.
 

Vance

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An excellent suggestion Jeff!

An excellent suggestion Jeff!

Thank you Jeff,

I wish you could be at our design meetings with all your experience in the “aviation way” of doing things.

One of the things we discovered is we could weld it to the engine mount. We rejected that as being not very useful.

Having the mount for the empennage be easily removable would make Mariah Gale almost six feet shorter for transport.

Properly executed it would not significantly weaken the structure.

We don’t like the weight of the fasteners and the extra complexity of the interface but the idea is not off the table.

I know the “aviation way” is to use small bolts properly in sheer and that would diminish our objection.

As far as repairing damage, both Jim have bent a lot of motorcycles and we have gained skill at repairing a complex weldment.

As I write this I realize that your idea has real merit.

I will run the idea past Jim in a more forceful way and blame it on you and the “aviation way”.

It would be great if more people would share their ideas on this thread.

Even if it is simply a negitive opinion of something we have done or are going to do I will learn things when I try to defend our position.

I am certain there are many good ideas we have either not considered or rejected because I am mentaly lazy.

I feel it is useful to remember we have never built a gyroplane before and we don't have a lot invested in our ideas.

Thank you, Vance
 

Vance

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Confessions of midnight madness.

Confessions of midnight madness.

I feel a description of how the new system works and why seems in order.

True to my roots it is like two motorcycle swing arms, with the bottom one being wider. This design would be called a trailing link. Because the swingarms are parallel the struts move up and down in a straight line. At flight attitude the swing arm links are straight back and present a very small frontal area. There is any number of ways to drive the coil over dampeners from the lower swing arm or we can use a pull shock from the upper swing arm. The driver would be inside the body as would the coil over dampers.

The center of the swing arms provides roll resistance. I am familiar with this because eliminating this flex was the key to getting some motorcycles to handle in the 60s and 70s.

This allowed a redesign of the keel for a straighter, shorter shot.

The bend in the new keel opened some mover possibilities.

Several people have commented that they enjoyed being in on the design process.

So if you like, follow along through the steps that led to this change.

I feel that Ed makes me sound a little eccentric.

There is actually a sequence in my madness.

I feel an important part of the design process happens when there is a design freeze.

I have heard it referred to as putting it in the box.

The best idea in the world isn’t good for much if it never gets tested.

At some point the changes have to come to an end, the material is ordered and the thing is built.

I have always had trouble with the material talking to me and telling me what it wants to become.

I have to learn to block out the little voices.

We have had a design freeze on the keel, suspension and empennage for many months.

It is what allows Jim and Vince to invest time in fabricating the pieces.

An engineering change order is the formal name for what makes everyone frustrated because they have to scrap what they have done.

I try very hard not to make changes after a design freeze when I hear the voices of raw materials and how they would like to be transformed into a proper system.

This was a multi step recursive procedure and most of the ideas had been tried and rejected previously because they did not work together as a system.

I stumbled across the key to this design as I pressed the edge of what I had learned on the drive back from Greenwood.

I was trying to imagine a slimmer, lighter, faster Mariah gale.

The keel and interface was not aerodynamically clean and the more slippery the rest of her was the larger percentage the form drag of the interface was. A cover over the keel helped but there was no help for the interface other than to lay the tubes down enough to fool the air into thinking they were a streamlined shape.

With the suspension attached to the keel we were very limited in what we could do and the interface needed to be strong side to side. As the angle of our pushrods to operate the coil over dampeners was reduced the side forces increased. Jim wanted to keep them short. The loads go up by the square of the ratio.

The keel/empennage mount is only vaguely in the area of the suspension pivot point so it made the whole assembly longer and the load paths less direct and left me confused.

These two divergent items need to be strong in different places and in different ways.

My original suspension design stepped around this by not having the keel as the suspension pivot.

It was complex, difficult to fabricate, used expensive materials and just didn’t fit so Jim rejected it and I concurred.

Until I found out how strong the wings struts were I felt we didn’t have aerodynamic material strong enough to manage the landing loads without a lot of structure and the structure always ran into things and diminished the purity of the design.

When designing something with a lever I always try to have the lever at right angles mid travel.

My original design had the links inside the body. That made for some ten inch long slots that I didn’t like. When I made some doodles of outside linkage they looked dirty at an ugly angle to the wind. We would have one link below the centerline of the body and one above so we would have things sticking out pretty far to clear the body through its ten inches of travel.

I drew it up anyway so I could better quantify the drag and compare it to the drag of our inelegant interface.

The first breakthrough for me was when I realized that the links could be straight back in flight and it didn’t matter what angle they were or how dirty they were at any other point in their lives. I felt they would need to be tapered in the correct direction for aerodynamics.

The struts end up mostly in compression, exactly what they are designed for. I was surprised to find out how steep they were. Looking back is makes perfect sense. The body is almost 3 feet wide and the inside of the wheel/brake is under 6 feet so allowing some distance for the link I have less than 16 inches to manage with almost 6 feet on length. This leads to a very shallow angle.

The lower links had to be way outside the body so the upper links could clear with the struts at an angle.

I didn’t like how far they had to stick outside the body but it allowed for more suspension travel without loading things with tire scrub. It also allowed us to design a keel with a more direct connection because it no longer had to handle the suspension and spring side loads.

We had been down this road when we considering using one of the aluminum spring type main gear built by Grove. That concept was rejected because we felt it was heavy, 22 pounds, and we wanted dampening that is not provided by that type of suspension on wet grass. We did like the structure of the keel better.

As this process progressed the keel angle was more and more divergent from the angle of the horizontal stabilizer. The mounting slot started to create drag. I felt it was time to revisit the mounting scheme for the empennage. At first I just stuck some brackets on top of the new keel and used the notch.

Once I had the bend in the truss under the propeller it was not hard to imagine mounting the empennage higher and the advantages that would bring in managing torque roll. I originally raised it because it looked better centered on the prop but it did not take much to appreciate the torque compensation that the tall tail being centered on the propeller provided.

I realized that notching the front spar and the lower surface and making the loads go around a corner might not be best practice. It was a convenient and the best we could come up with at the time.

After much iteration I had something that seemed like a reasonable compromise for the keel.

The empennage cried out to have her spars left intact and the interface more direct.

Leaving the lower skin intact seemed to add value and structure as it located the bottom of the spar.

I had not considered it before because I liked the way the keel fit into the slot in the lower surface of the empennage and I stopped thinking about that detail.

I went back to bed trying to imagine the details.

When I realized I could take advantage of the bodies shape because of the angle of the struts it was back to doodling. The relationship of things is a little complex to try to imagine in the dark.

With the lower link at the wide point of the body we could mount the links in close to the body and as the suspension compressed we gained clearance.

Because the upper link was only going up it could be right in against the body also.

I felt that everything fit best and had the least drag in the flight attitude.

From that point on it was simply finding a place for familiar parts, determining relative strength, selecting material sizes and wall thicknesses.

Finally I needed to calculate the weight of the pieces.

I felt like I was on the home stretch.

If I was going to approach Jim to tell him I wanted to throw away six weeks of his work I felt I needed to be prepared.

I find Jim’s intellectual prowess very intimidating and he is good at getting to the heart of a thing in cynical comedic way.

In my opinion the call at 6:30 AM didn’t go well so I decided to head back up to Greenwood.

I am also prone to forgetting just where things are located on Mariah Gale and with my Cad on the fritz I am even more prone to this sort of brain fade.

Once Jim understood the suspension everything else just sort of fell into place.

We had fun holding the material we would use in place to see how it looked.

We sized some of them for asthetics.

We thought we ran into a road block where the frame kicks in until we realized the body did not follow the frame closely. The coil over dampeners will fit inside the body and outside the frame.

All of the stress points seemed to find a junction to nestle into.

The more we imagined and mocked things up the better it looked.

I am very excited about the design change because it scores well on aesthetics, structure, use of materials, load paths, weight, aerodynamics and relative simplicity.

I expect the design to change as we figure the details of the fabrication and actually test the strength of some of the components.

I have not been able to silence the voices. Food calls to me too.

Thank you, Vance
 
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StanFoster

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Vance- the more I know you, the dumber I become. Your intuitive thinking is going up exponentially. What a driven person you are. Thanks for sharing your deep thoughts. I was iin a trance myself today coming up with an improvement in my wiring to my main fuel solenoidam. I had an idea that just hit me about using some more diodes so my backup battery can power it also. You and I in deep thought, but yours is vry complexm. Stan
 

Vance

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Life Treats Me Well!

Life Treats Me Well!

Thank you Stan,

I am trying to share the fun of the creative thought process.

Jim and I were like a couple of little kids holding up different pieces of tubing and calling out excitedly when we found something that fit somewhere or some way to work around a challenge.

I feel you do the same thing.

Most of the time for me it leads nowhere, sometimes things fit together and it works.

I have seen people get discouraged by the failures and stop trying.

I suspect most on the forum have not given up that childlike enthusiasm and it is part of the fun of building things that fly.

I see you do it as you learn about helicopters trying to fit the pieces together.

I see you do it when you figure out some way to make your Helicycle more special.

I feel it is not a competitive sport and another’s success only enhances my efforts.

I have the greatest respect for your creative process.

I have found that hanging around with other creative people enhances my efforts.

I feel fortunate to know people like you, Jim, Vince, Smokey and Mike.

I feel fortunate to be here on the forum.

Life treats me well!

Thank you, Vance
 

JEFF TIPTON

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Vance not all bolts are loaded in shear. If you look at many of the aircraft with Lycoming engines, there engine mounts bolt to the firewall with the bolts loaded in tension.

Also, most the Beechcraft products wings are attached with the spar attachment loaded in tension.
 

Vance

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The Aviation Way

The Aviation Way

Thank you Jeff,

I have come to refer to things that are different then how I have seen things done outside of aviation as the “aviation way”.

A good example is all the breakers and separate circuits on aircraft.

On road racing motorcycles we try to keep wiring and switches to a minimum. Most of my racing bikes had just one wire and a kill switch.

Another example is aviation bolts.

They tend to use much smaller bolts in aircraft if the joint is properly designed. I have almost never used 3/16 bolts on anything and yet a -3 seems a common size on aircraft.

Aviation seems to me to like to use more and smaller fasteners than in other types of vehicles.

Their affection for magnetos, points and dual ignitions in another example of the “aviation way”.

Jim and I based on our experience would probably use 3/8 bolts to fasten the empennage frame where as on many aircraft 4 -4s would be appropriate with more carefully designed joints.

I realize there are no hard and fast rules and the dynafocal mounts on my IO-320 B1A are a good example of large bolts for the task in tension. If I remember correctly the bolts that hold the mount to the frame are -6 and the joints are not all that well designed. It seems to be a common way to do it. I think on the next aircraft we would weld the engine mounting ring in place but still use the dynafocal mounts with their large bolts.

I feel it would not be that hard to design joints that have the bolts in shear and use perhaps four -5 bolts because we have not fully embraced the “aviation way.”

I feel your suggestion had considerable merit and I have been working on the scheme.

The motorcycle racing way to do it is to make a complex weldment to minimize the hardware with properly designed joints with fish mouth gusset plates to minimize local stress.

We feel these different philosophies have to do with the sorts of loads a motorcycle encounters compared to an aircraft. The peaks seem to be higher and sharper with a motorcycle but the repeated loads may be stronger in an aircraft. This makes the failure mode different calling for different techniques.

Your considerable aviation experience is very helpful to us in learning the “aviation way.”

Phil, my IA friend and Don, a local avionics shop owner are often schooling us in the “aviation way.”

My friends and I working on this project are a bunch of old people with a racing background that have never built an aircraft so we need all the help we can get. Jim’s sailing background is often very helpful too.

I realize because we are building a gyroplane with an odd mission that much of how it is done typicaly on gyroplanes may not apply.

I am grateful for any scraps of information or questions about our process from people on this forum.

The thread has had quite a few people looking at it repeatedly and I would love it if more would speak up as you have Jeff.

As an aside our in-flight adjustable horizontal stabilizer trim may be back on the table because of the redesigned keel/empennage interface.

I have cleaned up the doodle a little in the process of getting ready to present the engineering change order to Vince.

My doodle program is still not whole and they no longer support it. I may have to learn a new program.

The doodle is with the gear fully extended at flight attitude, that is why the nose gear apears high, it has less travel.

Thank you, Vance
 

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Vance

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Fantasy collides with reality.

Fantasy collides with reality.

I did some weight and balance work on Mariah Gale this weekend and then had a meeting with Jim this morning.

In my last doodle I feel the mains likely are too far back for the balance we are looking for.

By using the structure of the firewall we can manage the pivots for leading links rather than trailing links.

It will still use coil over dampers inside the cowl

Until we have more parts made and have a sharper picture of the location of the center of gravity our focus will be on the new keel and empennage mount.

Jim likes the idea of bolting the new mount because it makes a lot of things a lot easier.

The lines of the body will define themselves so I just doodled them in as a place to start the process.

Jim wants to taper the legs on the main gear and I have to admit that would look nice. It seems like a lot of extra work for not much weight savings. They do that on spreaders on sails. Jims nautical background is always just under the surface.

I am working on my fantasy of an in-flight adjustable horizontal stabilizer.

Thank you, Vance
 

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Vance

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Tentative mockup progress?

Tentative mockup progress?

I feel we are overcoming the setbacks I have created with the keel redesign.

I spent a lot of time doodling but there is nothing like a full scale mockup.

I hope the pictures are clear enough to make sense.

Picture 1&2 are the airframe from the back using my die table at the empennage.

The airframe is the height it will be.

I added another challenge by wanting room for a 72 inch propeller based on what I learned at AirVenture and a longish talk with Craig Catto on the drive home from Mentone. We were making room for the 68 inch three blade propeller that is on the Predator now.

Pictures 3 and 5 are the full scale mockup from the side. The yellow pieces of paper represent the radiuses Jim has dies for.

The T square is what we use to manage the height of the bends. We are trying to understand the angles for the bends beneath the propeller.

Picture 6 is the engine mount to help us understand what size tubing to use for the keel. As you can see the tubes in tension, .625 are smaller than the ones in compression, .750. We are going to use .750 for the keel.

The string in the picture is what we use to keep things aligned. You will see it in use in the last picture, 12 although it doesn’t show up well. It is how we check motorcycle frames for straight after an unscheduled dismount.


We are going to put 2 steps to get into Mariah Gale on the leading edge of the struts.

I purchased two more Cessna Wing struts at the Fly Market at AirVenture for $20.

Jim will order the tubing for the keel on Monday. Each of the four .750 inch .049 wall pieces is about 8 feet long.


Thank you, Vance
 

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Vance

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More Doodles!

More Doodles!

The doodles are a rough idea of the suspension as it goes through 8 inches of travel.

Jim and I have some disharmony here. Jim feel that 8 inches is enough and he does not like the complexity of the release mechanism for the last 4 inches of travel. I would like to see 12 inches of travel with the last 4 inches being restricted unless an inelegant landing is imminent. We may get more travel with longer arms depending on where the mains end up.

The nose has 6 inches of travel and Jim is going to make it longer to manage the larger propeller clearance with a level attitude.

I have other doodles with dimensions but they don’t come out well in a Jpeg.

The tail wheel has been enlarged and moved to the frame just behind the propeller since the doodle.

The line is for seven degrees of rockback. I have also checked the empenage/rotor clearance with the the new location for the empenage at the mast height in the doodle at 26 degrees.

I am on the road to Bonneville Speed Week and it is time for me to go to bed as we start at sunup.

Thank you, Vance
 

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Riff Raf

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Sorry
I don't see any detail in these drawings as to the suspension design.
 

Vance

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I did not mean to confuse.

I did not mean to confuse.

Sorry Roger,

I described the workings of the new main gear suspension in post 515, 519 and 520.

I didn’t want to seem repetitive.

The doodles are about what angles and travel can be managed easily.

In the drawings the swing arm legs are about 18 inches.

Longer would give us more travel before the geometry becomes untidy.

I wanted the legs to be in line with the airflow in flight and the upper one interferes with the body if it goes below level.

The nose gear is leading link like a girder front end on an Indian and all the mechanism is inside the body with only the streamline tube emerging from the body.

Thank you, Vance
 
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JEFF TIPTON

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Vance wondering if your rear suspension is similar to the front end of the old Volkswagenn Beatle?
 

Vance

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Coil over dampers instead of torsion bars.

Coil over dampers instead of torsion bars.

Precisely Jeff, only without the torsion bars.

They are connected side to side so when one wheel goes up the other has a similar response.

We can control roll resistance with the strength of the connecting tube.

I feel this is important with the long travel, soft springing and high center of gravity.

We will probably have a coil over damper on each side

The front suspension is sort of half of that.

Off to the races, Vance
 

SgurlEd

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Impressive!

Impressive!

It's always amazing that Vance's late night mental wanderings always turn out to be some really amazing things.

To see the pictures helps so much...you know he wakes me up it the middle of the night to share his ideas but I can never really quite see what he see's until I see the photos and mock ups it helps so much...and I am impressed!

This is going to be one wicked Autogiro! Thanks for posting the pics Snooky!
Love, Ed
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,160
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
Better dimensions.

Better dimensions.

I stopped by Hollister on the wake back from Bonneville Speed Week and shared the progress with Mike and Vince.

Jim needed a more accurate measurement on the height of the empennage because we want to center it on the propeller. I had only guessed at the height before because I did not what to move it.

Today we took the empennage plug down and blocked it square on the floor so we could get an accurate measurement.

It was a good thing because my guess was 2.75 inches shorter than reality.

From the top of the vertical stabilizer to the bottom of the horizontal stabilizer is 55.75 inches.

Vince was ready to make parts but Jim and I both felt he should have the keel before he finishes up the bottom of the Horizontal stabilizer.

Vince wants to make all the parts at once because they move around as they cure.

Jim is hoping to have the new keel finished in about 3 weeks.

Thank you, Vance
 

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Riff Raf

Newbie
Joined
Sep 16, 2007
Messages
682
Location
USA
Aircraft
Air Command 503 & RAF 2000 GTX SE (with some mods.) Tierra W/ Tri-Gear
Total Flight Time
16 dual in Sparrowhawk and a few more in other Gyros, 250 in FW
Winglets on the HS??
They will help with yaw.
 
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