Crescendo Build

Resasi

Gold Supporter
Joined
Jul 2, 2007
Messages
7,391
Location
London/ Kilifi Kenya
Aircraft
Gyrs, RAF 2000/Mgni/Bnsn/Hrnet/Mrlin/Crckt/MT-03/Lyzlle AV18-A/Prdtor. Pax ArrowCopter
Total Flight Time
100+ gyro, 16,000+ other
Have spoken to him and it seems at his home airfield he has been doing low and high hops and getting comfortable with it so seems he has got the hang of things OK.

Apologies for thread drift.
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
Good morning, All.

I would like to ask the experts here before selecting and purchasing a safety belt harness. I'm seeing a variety of different buckle types, etc. and wanted to know if a certain style is preferred for aircraft use and why. I'd rather use a 4-point restraint instead of 5-point, but am consulting the Forum before any choice is made. Thank you all in advance for any insight or recommendations.

Regards,

Brian Jackson
 

gyrojake

Gyro Rehab Candidate
Joined
Jan 1, 2007
Messages
2,219
Location
E-City, Florida
Aircraft
Gyroplanes
Total Flight Time
A few hours
I like the single over the lap with a push button release.
I also like a very easy to release belt, Ya know in case your ass is burning up or under water!!!
You can get them on eBay for like 10 bucks
Now if you plan on rolling it over and flipping it a few times on the ground I'd use a 5 point harness
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
I like the single over the lap with a push button release.
I also like a very easy to release belt, Ya know in case your ass is burning up or under water!!!
You can get them on eBay for like 10 bucks
Now if you plan on rolling it over and flipping it a few times on the ground I'd use a 5 point harness
Thank you, Jake. These are things I will consider before purchase. I've seen something called a "lift-latch" system on some of the high-end racing harnesses that I assume is for quick release. Planning to keep the ship right-side-up at all times, but designing it for that just-in-case cartwheel. Would rather be prepared for the scenarios I can't imagine right now.

By the way, I selected and purchased the coil-over shocks this morning after weeks of research Q&A. Holy cow that was a longer journey than expected. I have a deeper appreciation now for the art/science aspect of designing suspension systems. Way more involved than first thought. Did a quick, simplified diagram to show the stroke, deflection, loads, etc. that was easier than explaining verbally during conversations with the pros. Hopefully we nailed it.
 

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Tyger

Active Member
Joined
Nov 25, 2017
Messages
294
Location
Germantown, NY
Aircraft
Magni M16
Total Flight Time
225
Good morning, All.

I would like to ask the experts here before selecting and purchasing a safety belt harness. I'm seeing a variety of different buckle types, etc. and wanted to know if a certain style is preferred for aircraft use and why. I'd rather use a 4-point restraint instead of 5-point, but am consulting the Forum before any choice is made. Thank you all in advance for any insight or recommendations.

Regards,

Brian Jackson
I am no expert on these things, but my understanding is a four- (or five-) point restraint is mostly useful if there is a possibility of hitting something while moving forward (e.g. in a race car). That kind of crash is a lot more likely in an airplane (needing a long rollout) than a gyro, for obvious reasons. Another issue with them will be finding satisfactory points to attach the shoulder anchors, keeping the potential forces in mind. I think a lap belt is really all you should need. They are all I have. :)
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
Haven't posted in a while so thought I'd share a couple of things consuming my time on the build these past few weeks. One of the items (not pictured in this post) is a 3-piece CNC machined interlocking bracket system that attaches the shock absorbers to the mast. It ended up being a very sculptured looking design just by capitalizing on how stress loads flow and by utilizing existing holes and frame members. No new holes in the airframe. I will elaborate more in a follow-up post.

The other item (pictured in renderings below) is the connection between the shock and the landing gear vertical strut tube. These shocks came with a clevis that I had intended to use as a hard attachment point, but after dissecting the unit came up with a cleaner, simpler connection method that uses a single bolt in-line with the tube. Not shown in the rendering is the adapter plug that threads into the shock where the threaded clevis used to be. This plug gets drilled and tapped to accept the 5/16" bolt you see in the image. The cone bracket is lathed to seat over and onto the solid lower body of the shock to form a tight, rigid structure when the center bolt is torqued down.

My thought was that the threaded portion of the discarded clevis could be sawn off and drilled/tapped to form the plug adapter. However since it is made from aluminum (grade unknown) I will more than likely be making new ones from steel metric threaded rod. Reusing the existing clevis nipple is certainly tempting but not knowing the alloy leaves too much to chance and luck.

Edit: the internal stair-stepping is slightly different in this original concept rendering. Final shaping is more fluid with no sharp inside corners. Also 1/2" shorter than shown.
 

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Jazzenjohn

Gold Supporter
Joined
Oct 9, 2004
Messages
2,731
Location
Milan Mich.
Aircraft
Gyrobee, My design
Total Flight Time
350
I know your fairly lightweight Brian, but a 120 pound spring rate seems low to me. You should ask GyroJake to check my numbers since I don't use weighty shock absorbers, just fixed axles.
 
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Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
15,800
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2200+ in rotorcraft
In my opinion based on my experience with motorcycle suspension the need for a spring rate goes up by the square of the ratio. In this case it would be 1.43 X1.43 or 2 to one.

When considering suspension you must also consider droop (how much the suspension is compressed at maximum takeoff weight.

I you are only dealing with landing loads (smooth surface operation) I feel there is no reason to manage 2.5 Gs.

Too much suspension travel can make a gyroplane feel tippy on the ground.

If it was my project I would get some available spring and see how it works and expect to change it.

Because you are using a hydraulic dampener some of the load of impact can be managed with compression dampening on a smooth surface.
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
I am double-checking those numbers. The spring rate on the diagram may have been mislabeled. But I am also prepared to swap out springs if needed during the initial test taxis.

Last night I finished the exterior surfacing for the shock lower connecting brackets (the inserts that adapt the shock units to the vertical strut tubes). I've posted similar operations earlier in this thread so won't bore anyone with a redundant write-up. But one of the recurring design elements of this ship is the double-curvature of many of the inserts and connections. Since I don't own a CNC lathe, I machine dense stair-stepping and spend a few hours/days hand filing smooth. The blue dye stays in the inside corners of each stairstep and helps me control the final curvature until they disappear.

The last quarter or so of the part will be removed, as will be the end portion of the larger diameter near the jaws. Before the part pictured is unchucked there will be a 1.75" long tenon portion lathed down to fit within the vertical strut tube. From there it will be milled/bored to precisely fit over the lower (factory lathed) end of the shock.

Soon it will be time to assemble all the piece parts that have been years in the making. I must be nuts for that sentence to be true.
 

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Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
Just sharing something I learned from our company's guru machinist, Ziggy. Old trick but new to me. I needed a way to clamp the part to the drill press bed to perform a partial boring operation. But round things are hard to grip and I didn't have a vise that would grab the part low enough (at the bottom flange; the scrap end that is gripped by the lathe chuck) and keep it square with the bit.

Turns out my company has several size chucks that I was allowed to borrow one of. The photo is self-explanatory. Since I had already lathed both ends flat and square before doing the outside shaping, it sits true on the face of the chuck before and after tightening.

It would have been nice to do this drilling while still in the lathe, but my mini-lathe just didn't have the bed length to allow that.
 

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Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,917
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
We finally got time to fabricate the revised engine mount plates. It has been difficult to commandeer the CNC machine at my company due to continuous workflow, but we made time after hours. The new plates were designed to flip the Barry mounts such that the larger hole is through the wider plate. That was a mistake I had made on the first set. Of note: the Barry mounts will now span 3 across instead of 2 (total of 6 mounts). The middle mounts are to increase radial load capacity. There is an earlier write-up in this thread about that.


1 emcnc.jpg2 emcnc.jpg3 emcnc.jpg

Test fitting went perfectly. I haven't installed the Barry mounts yet, so the image just shows some rubber spacers I used for the photo. The new plates are also a bit narrower than the old ones (by design). Due to that I will be machining the aft ends of the horizontal engine mount angles to mimic the plate's curvature and bevel angle. Totally unnecessary but would bug me if left unfinished.

Many thanks to Alex for his masterful CNC chops.
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
15,800
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2200+ in rotorcraft
I admire your attention to detail Brian.

You continued progress is an inspiration.

I look forward to seeing her in person one day.
 
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