Crescendo Build

Learned a cool trick during this weekend's gyro build. In the process of turning a 6 lb. billet into a 4 ounce part, the conical cuts proved difficult to measure for setup. So I borrowed heavily from my pencil and T-square days as a mechanical draftsman . The part is modeled in CAD so I was able to print a full scale paper template with reference lines to align the part directly over. The shaded area on the template is the finished part.

A tilting vise rotated vertically is clamped to a piece of angle that slides against the side of the band saw table. Works like a T-square. Clamping the workpiece at the designed angle was made easy by placing a small square on the template at points along the profile line and nudging the part until it contacts the square.

Pictured below is a test cut an inch or so away from the designed cut. Final surfacing will be on milling machine so this step doesn't have to be accurate to the degree, but it is. Buying an expensive angle finder was an option but this method turned out to be both accurate and free.


The link above is for the tilting vise which is proving indispensable in the shop. It was $50, operates smoothly, rock solid and very well made.

Haven't posted on this thread in a while but have been busy building a gyro. Even if it's only 30 minutes on some evenings. I try to make tangible progress every day.
 

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Am further along but thought I'd post some progress pics. Made good use of paper templates, both to protect the outer surface and to have visual cut and reference lines to aid machining. I used my little plumb laser to align the reference centerline before spray-gluing them on. Used clear tape at 2 points before gluing to keep its position on the part.

The milled tenon on the small end is only for support in the tilting vise and is removed during the milling of the clevis slot. The milled surface you see in the photos is only temporary. More material is removed later on at a different angle, but this surface gets drilled and tapped to accept a fixture plate. The whole thing gets flipped plate-down and secured to the milling machine so that the clevis slot can be cut at the correct angle. I spent this weekend finishing the fixture plate and getting things set up for final machining. Will share more pics.
 

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Realized I hadn't posted any follow-up pics. This is one of the mirror-image pair (left & right are opposite) of the upper shock clevis brackets I photographed earlier in their fabrication. The wide bottom of the cones mount against the mast on plates that extend down to the existing bolt that already connects the horizontal engine mount angles. No new bolts or holes in the mast needed. The plates they mount to (not shown in these photos) serve double-duty, taking the place of the spacer washers that would normally go between the mast and the engine mount angles.

I was surprised how well the glued-on paper templates worked in practice, as they proved 100% accurate for controlling the compound angles needed to keep the cones centered about the mains' vertical struts at nominal load.

There's a couple more machined features on them I haven't photographed yet but you get the idea. The final parts only weigh about 4 oz. but each of them started as a 6-pound billet. The rest is scattered evenly throughout various carpets in the house, much to the joy of my wife.

One thing I've learned as a novice to machining is that it's super easy to design a part that's impossible to build without some way of clamping or holding it in the machine. Even harder if you don't want it scuffed up and pocked with tool marks. So I cut the bottom bevel in 2 stages. The first stage allowed me to screw in a temporary steel plate that locked down to the milling machine and cut the clevis channel. Then it was removed and the lower portion sawn off and final milled to the correct pitch and slope. To do this the steel plate was repurposed and paired with an adjustable pressure plate that secured the part on all 3 axis. My phone has a sensitive inclinometer that turned out to be quite useful when making the slight 0.1 degree adjustments in the final surfacing.

But the real beauty of looking back at all these steps is knowing I never have to build these again!

I did purchase a nosewheel block assembly from Sport Copter that should be arriving tomorrow. Though that might be cheating a little in the spirit of true home building, I believe it was a lucid decision for reasons discussed in another thread. My hope and goal is to finally have a rolling airframe in the next few days. I am very grateful for the members of the Rotary Form who have coached and encouraged me since the beginning. Without your guidance and support this project would not have been possible. I will post pics of the assembled airframe as soon as it's done. Thanks.
 

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Realized I hadn't posted any follow-up pics. This is one of the mirror-image pair (left & right are opposite) of the upper shock clevis brackets I photographed earlier in their fabrication. The wide bottom of the cones mount against the mast on plates that extend down to the existing bolt that already connects the horizontal engine mount angles. No new bolts or holes in the mast needed. The plates they mount to (not shown in these photos) serve double-duty, taking the place of the spacer washers that would normally go between the mast and the engine mount angles.

I was surprised how well the glued-on paper templates worked in practice, as they proved 100% accurate for controlling the compound angles needed to keep the cones centered about the mains' vertical struts at nominal load.

There's a couple more machined features on them I haven't photographed yet but you get the idea. The final parts only weigh about 4 oz. but each of them started as a 6-pound billet. The rest is scattered evenly throughout various carpets in the house, much to the joy of my wife.

One thing I've learned as a novice to machining is that it's super easy to design a part that's impossible to build without some way of clamping or holding it in the machine. Even harder if you don't want it scuffed up and pocked with tool marks. So I cut the bottom bevel in 2 stages. The first stage allowed me to screw in a temporary steel plate that locked down to the milling machine and cut the clevis channel. Then it was removed and the lower portion sawn off and final milled to the correct pitch and slope. To do this the steel plate was repurposed and paired with an adjustable pressure plate that secured the part on all 3 axis. My phone has a sensitive inclinometer that turned out to be quite useful when making the slight 0.1 degree adjustments in the final surfacing.

But the real beauty of looking back at all these steps is knowing I never have to build these again!

I did purchase a nosewheel block assembly from Sport Copter that should be arriving tomorrow. Though that might be cheating a little in the spirit of true home building, I believe it was a lucid decision for reasons discussed in another thread. My hope and goal is to finally have a rolling airframe in the next few days. I am very grateful for the members of the Rotary Form who have coached and encouraged me since the beginning. Without your guidance and support this project would not have been possible. I will post pics of the assembled airframe as soon as it's done. Thanks.
A real work of industrial art, Brian. Congrats.
 
Thanks for sharing the pictures Brian. That's certainly not the easiest of shapes to hold, well done and they look great! 👍
 
Nothing glamorous this entry but progress nonetheless. Threaded inserts replace the original clevis brackets that came with the dampers. Learned that the outside thread die has an adjustment that lets you perfectly dial in the cut diameter to control how loose or tightly it engages with the mating part. Found that sweet spot. Blanks were lathed and drilled to diameters specified in the thread standards. Insert lengths equal to maximum threaded depth of damper.

There is a small set screw that passes through the damper and insert walls that acts as a key to prevent rotation of the insert. The lower shock cones (photographed in an earlier post) are bored for a tight tolerance fit over the threaded assembly. The cones are hollow and are secured to the damper with a socket head bolt that passes up from below. The dead load is on the milled end face visible in image 4.

I was also able to test-fit the new Sport Copter nosewheel assembly that arrived on Friday. Like a glove. Happy to report the high quality, robust design, light weight and maintained my target keel height. With the nosewheel in place I can now size the main vertical struts' length once this assembly is unitized and mounted.

Edit to add: Am a big fan of plexiglass strips in the vise. Outstanding grip on the workpiece without damaging it or marring the surface. You can see the two plexiglass strips in image 3.

You know, this project has given me a new appreciation for the movement of glaciers.
 

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You and our build team.

That’s some nice work there Brian, now that’s a build, and some pretty craftsmanship.
 
"...I was also able to test-fit the new Sport Copter nosewheel assembly that arrived on Friday. Like a glove. Happy to report the high quality, robust design, light weight and maintained my target keel height. With the nosewheel in place I can now size the main vertical struts' length once this assembly is unitized and mounted."

Photos of that coming forthwith, Brian? (Gives us something to look instead of the usual political/pandemic issues ever-present in the news)
 
"...I was also able to test-fit the new Sport Copter nosewheel assembly that arrived on Friday. Like a glove. Happy to report the high quality, robust design, light weight and maintained my target keel height. With the nosewheel in place I can now size the main vertical struts' length once this assembly is unitized and mounted."

Photos of that coming forthwith, Brian? (Gives us something to look instead of the usual political/pandemic issues ever-present in the news)
OK then Kevin. Will post a virus-free nosewheel photo today. I have to notch the keel on front due to the way the inserted portion nests, but will go into more detail in the upcoming post.
 
Good morning, Kevin.

Sorry I didn't get to post these last night but here they are. The assembly isn't mounted yet, only partially inserted into the keel. Jim Vanek and his crew did an amazing job with tube wall clearances, etc. There is a special grease that goes between the 2 friction discs, and a centering spring that runs along the underside of the keel (not shown). It's extremely well made, fairly light, and I feel better about having the shock damping elements to minimize sudden fore/aft jarring of the upper mast over rough terrain.

The red items in photo 3 are the compressible rubber dampers. Not sure how much spring energy will be returned, but an unexpected rock or divot won't feel like an impact load to the rotor and folding mast plates. The composite rotor is heavier than other blades, and the tall mast of a 'Bee makes for a long moment arm. So anything I can do to smooth ground handling is being addressed.
 

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These are a few days old and am posting for posterity, mainly to show the FAA airworthiness inspector(s) and the test pilot how things connect and what steps were involved. Not much progress this week as I've had 2 weddings to attend and a growing honey-do list to keep up with.

This is one of 2 completed matched L/R damper assemblies that connect the mains' vertical struts to the mast. Temporary hardware used for photos. The set screw in image 2 does not extend into the bolt hole of the threaded insert. It stops 1mm short and simply acts as an anti-rotation key for the insert. The lower tube adapter cones are bolted up through the center with a 5/16-24 SHCS. It will be secured with a lock washer and loc-tite on the threads during final assembly, though I would like to consult the experts here for the preferred type of lock washer and thread cement.

There are still 2 threaded bores to machine on the flats of the upper clevis. These need to be transfer-punched from matched holes in the mast plates they attach to. Also have to finish lathing the spacer washers that go on each side of the eyelet. Clearance space is visible in image 4. Getting close to having a rolling airframe. More to come.
 

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Bloody terrible Brian, maybe in future you should consider getting an expert in to assist so you can get some decent parts made :D.

wolfy
 
Bloody terrible Brian, maybe in future you should consider getting an expert in to assist so you can get some decent parts made :D.

wolfy
Yeah, really should have spent more time on it. Said no wife ever. :unsure:

Thanks guys. Means a lot coming from the great talent and expertise we have on this forum. After this the progress should speed up. Still have the tail, pedals, upper mast and cyclic linkage/stick to fab, along with all the smaller bits still to address. Funny how the design has evolved over the years, with many of the originally intended complexities being shed in favor of tried and true simplicity. An example being the custom seat and fuel tanks reducing to a clean, simple seat tank. Knowledge of the frequency of post-crash fires drove some of that, and many other educational discussions here like tailboom deflection/twist drove the design for the reinforcing structure. Hopefully the end result justifies the build time.

Cheers
 
Update: For the first time as of last night, every piece I have built for the gyro is assembled. Holy shit it looks like an airplane! I've never seen it all put together before except as a 3D CAD model. Will take some pictures this evening to post.

Still to do:
Upper mast assembly & rotorhead
Seat mounting supports
Empennage fabrication
Mount engine
Brakes and rudder control linkages
...and 100 other items.

Feels surreal. Never expected it to take years to get to this point. Fortunately the parts that were hardest and most time consuming to fabricate are complete. Progress should accelerate now.
 
Brian, you do such great work!!
Thank you for sharing. I learn from your posts!
 
Brian, you do such great work!!
Thank you for sharing. I learn from your posts!
I'm honored, John, but feel it is I who has gained the most from the talented folks on this forum by putting some of that knowledge to practice. Hopefully the end result is worthy of the sweat equity.
 
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