Hoop Gear Suggestions
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J-Dubs
I know it is slightly off topic but I feel like the knowledge base here is also quite deep so I hope it is okay to ask. I have been trying to have a production run of hoop gear made for the Dragonfly list but have failed. I believe that I will have to make my own. This leaves me with a few questions:
1. Are there any design improvements that should be included? I am thinking of adding 2 fiberglass sleeves for the final layers to help prevent cracking. 2. In estimating material to get to 0.75" thick, do I just use the fiberglass thickness or do I add something to allow for wetted thickness? 3. Which resin is preferred for a hoop gear application?
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Steve Rothert
For what it is worth, the Long-Ez landing gear is made of unidirectional S-glass, from various vendors. The builder then has to wrap the gear with several layers of "BID" fiberglass/epoxy at a 45 degree angle. After the gear is mounted, then additional plies may be needed where the wheel axle mount to provide correct alignment for "toe-in", etc.
As for the final thickness, I would do some test layups to determine the number of layers of glass for the final dimension. You might want to read up on "post-curing" the epoxy/glass part too. Hope this helps. Steve
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These folks make a Long-EZ Main gear. Maybe a place to start by contacting them.
https://aerocad.com/landing-gear/84-main-landing-gear-strut.html
Cheers, Jay
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Steve Rothert via groups.io
Sent: Wednesday, January 19, 2022 9:25 AM To: main@Q-List.groups.io Subject: Re: [Q-List] Hoop Gear Suggestions
For what it is worth, the Long-Ez landing gear is made of unidirectional S-glass, from various vendors. The builder then has to wrap the gear with several layers of "BID" fiberglass/epoxy at a 45 degree angle. After the gear is mounted, then additional plies may be needed where the wheel axle mount to provide correct alignment for "toe-in", etc.
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Robert Cringely
I’d start by buying Pazmany’s book on landing gears, which explains everything you need to know. It’s available from Aircraft Spruce. Bob
On Wed, Jan 19, 2022 at 8:32 AM Jay Scheevel <jay@...> wrote:
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Steve Rothert
FYI.
It probably won't fit, but I have a "never mounted" Long-Ez landing gear, sitting in my basement. I bought it as a spare, several years ago from a guy who was parting out his Long-Ez project. Steve
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Raphael SF Zvetkoff
You can find Boeing both process specs and BMS (Boeing Material Specs) online. You'll be able to find everything from ply thickness per ply to the different resins used for each application whether it's in an autoclave or an oven or room temp cures.
https://www.scribd.com/doc/115312681/Boeing-BMS-Boeing-Material-Specification
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of J-Dubs <jwerth55303@...>
Sent: Tuesday, January 18, 2022 5:36 PM To: main@Q-List.groups.io <main@Q-List.groups.io> Subject: [Q-List] Hoop Gear Suggestions I know it is slightly off topic but I feel like the knowledge base here is also quite deep so I hope it is okay to ask. I have been trying to have a production run of hoop gear made for the Dragonfly list but have failed. I believe that I will have to
make my own. This leaves me with a few questions:
1. Are there any design improvements that should be included? I am thinking of adding 2 fiberglass sleeves for the final layers to help prevent cracking. 2. In estimating material to get to 0.75" thick, do I just use the fiberglass thickness or do I add something to allow for wetted thickness? 3. Which resin is preferred for a hoop gear application?
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Raphael SF Zvetkoff
I forgot to add this.
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Robert Cringely <bob@...>
Sent: Wednesday, January 19, 2022 9:22 AM To: main@q-list.groups.io <main@q-list.groups.io> Subject: Re: [Q-List] Hoop Gear Suggestions I’d start by buying Pazmany’s book on landing gears, which explains everything you need to know. It’s available from Aircraft Spruce.
Bob
On Wed, Jan 19, 2022 at 8:32 AM Jay Scheevel <jay@...> wrote:
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Michael Dunning
I believe there are a few examples of homebuilt hoop gear in the Dragonfly newsletters; page 7 of Issue 43 is just one example. IIRC, a latter issue even had color photos.
Dragonfly Builders and Flyers Newsletter - Issue 43 For the Long-EZ gear finishing Steve posted, Ary Glantz has a nice video of that process: The Long-EZ Build: Chapter9 - Part 2 -- -MD #2827 (still thinking about planning on visualizing how to finish building)
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J-Dubs
Steve,
Testing a few layups to see how size increases with time was my thought, I was just trying to avoid multiple shipments from AS&S. Michael, You are correct, DBFN 43 is the one that I am using for reference. It gives great information for the finished dimensions but doesn't say anything about the amount of fiberglass required. It also says S-Glass but that was corrected in later issues to E-Glass. Using E-Glass thickness of 0.012" the 5/8" thick section would take 52 layers assuming that the glass doesn't swell and another 52 layers for the 1 1/4" thick sections. I think that West Systems is the popular contemporary choice for resin but I am not sure.
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Steve Rothert
I helped a fellow builder install a Grove aluminum gear, on his Dragonfly. There were plenty of challenges in finding a location for the attach points, reinforcing the fuselage structure, machining the attach brackets, locating the holes for the hydraulic brake lines, etc.
Steve
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That would work also. But as you noted, not much real estate to work with at the fuselage and canard junction. Lots of
challenge. Still, it is a possible venue. Steve..using the Grove gear, how did the ramp angle work out and the gear stagger
to bring the C/L of the tires to the MKII location from the Datum? You see why I chose the RV7 gear design?
Not only for reasons of working out a lot of installation issues , but the design has been flying the
Experimental aircraft sky
ever since the W8/W10 plans were sent by Mr. Wittman. I am skilled enough in TIG welding this is not a big event to fabricate.
Vern in frozen (again) Oklahoma
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Steve Rothert via groups.io <SWROTHERT@...>
Sent: Thursday, January 20, 2022 10:09 AM To: main@Q-List.groups.io <main@Q-List.groups.io> Subject: Re: [Q-List] Hoop Gear Suggestions I helped a fellow builder install a Grove aluminum gear, on his Dragonfly. There were plenty of challenges in finding a location for the attach points, reinforcing the fuselage structure, machining the attach brackets, locating the holes for the hydraulic
brake lines, etc.
Steve
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Steve Rothert
We have not yet done a Weight & Balance. We took a lot of measurements when having the Grove landing gear made, in an attempt to maintain the same height off the ground. The pilot seems to sit just a bit higher, maybe 1 or two inches. Will try to take some pictures, the next time I am at the owner's hangar.
I'm trying to help the owner get signed onto this group, so he can particpate. Steve
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Jon Finley
I had a chance to take a look at Steve and Al's aluminum gear installation (in a DF) and they did a really nice job! The ability to remove the canard (and wing) from a DF has always been a neat advantage - being able to leave the airplane on its gear while doing so would seem to be a huge advantage.
Back to the fiberglass DF hoop gear, there used to be a 'plan' available for this gear. I half helped a fellow build one a very long time ago. Like the EZ gear (but wider, shorter, and more 'bow') it required a form and consumed a LOT of glass and epoxy but seemed to work just fine. Jon Finley Somewhere in the Southwest flying an RV-4
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Steve Rothert
See Photo section - Grove gear installation
Steve
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