Today's Message Index:
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1. 02:52 AM - Re: The Obsidian File - Mono Undercarriage (Dave Disney)
2. 04:21 AM - Re: Re: The Obsidian File - Mono Undercarriage (Pete)
3. 04:25 AM - Re: Re: The Obsidian File - Mono Undercarriage (Pete)
4. 07:11 AM - Re: The Obsidian File - Mono Undercarriage (Area-51)
5. 07:21 AM - Re: The Obsidian File - Mono Undercarriage (Area-51)
6. 07:28 AM - Re: Re: The Obsidian File - Mono Undercarriage (Pete)
7. 12:14 PM - Re: The Obsidian File - Mono Undercarriage (Jon Smith)
8. 01:23 PM - EZ Resolution for Leaking Europa Main Fuel Tank? (rparigoris)
9. 03:52 PM - Re: The Obsidian File - Mono Undercarriage (Area-51)
10. 10:57 PM - Re: The Obsidian File - Mono Undercarriage (Area-51)
Message 1
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
This is an interesting subject.
The question is asked what the bungee actually does. I replaced my bungee a couple
of years ago and did some retractions without it (aircraft jacked in the hangar
so no aerodynamic assistance). It was bloody hard work to retract without
the bungee. When I installed the new bungee it had 1 extra loop and was tensioned
a lot more than the one I removed. The gear is now really easy to operate
both in the air and in the hangar!
I'm not quite sure I agree with your overcentre analysis. I am one of the few who
have done a wheel up landing (not because I forgot, but don't ask how it happened).
After the landing the gear was really easy to lower despite the fact
that it had gone right up into the tunnel with the wheel contacting the throttle
lever and the brake caliper severing a rudder cable. With the wheel going this
far up, wouldn't your overcentre case be realised?
On another topic, I really like your 3D modelling. I have produced a Solidworks
3D model for the fuselage frame by taking measurements and reverse engineering
it. I'm doing this for a new conventional gear design I'm working on. I would
love to compare my model with yours, what software are you using for your modelling
and how are you going about it?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509440#509440
Message 2
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Fwiw, my throttle box serves that same purpose :)
> On Dec 4, 2022, at 12:34 AM, Area-51 <goldsteinindustrial@gmail.com> wrote:
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> Some further thoughts today upon this.
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> With a focus toward keeping things as simple as possible a fast solution to more
easily employ was brought in after a discussion with another Europian... The
latest mod employs a buffer stop mounted on LG02 to prevent the undercarriage
raising too far up into the tunnel and the rubber block assembly reaching the
geometric locking position. The height of the buffer can be altered by placing
washers under its base thus adjusting the parking position of LG02.
>
> The nut fixing the buffer to LG02 has been given the function of a jacking pin
for security and safety purposes.
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> Some photos included.
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> Read this topic online here:
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> http://forums.matronics.com/viewtopic.php?p=509439#509439
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> Attachments:
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> http://forums.matronics.com//files/587804b7_9dd3_4ce6_b887_fc4c72208f83_211.jpeg
> http://forums.matronics.com//files/93ab2be7_1f9a_4045_82c0_fd1fa71cc1f9_195.jpeg
> http://forums.matronics.com//files/529850f9_05da_4241_8a1f_a78394a10f4d_219.jpeg
> http://forums.matronics.com//files/4c0ad6f2_3280_45b2_9403_027bde1e7e9e_162.jpeg
> http://forums.matronics.com//files/a9494e6d_4ee7_4e33_8cb1_818685ac2352_488.jpeg
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
5/8x0.035
> On Dec 3, 2022, at 10:13 PM, Area-51 <goldsteinindustrial@gmail.com> wrote:
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> Nice solution Peter; what gauge tubing has been used there?
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> Read this topic online here:
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> http://forums.matronics.com/viewtopic.php?p=509437#509437
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Thanks, much appreciated... can i have your permission to copy your mod into the
mix?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509443#509443
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Today repositioning of the brake caliper was given a quick review after string
lining in the rudder cables; and it revealed that John had indeed flipped the
classic tailwheel block upside down to gain better cable alignment... a moment
force study was also commenced on yesterday's mod to LG02A to determine the affect
at the operator handle end of the situation; will have to run the same test
again on the current setup to compare.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509444#509444
Message 6
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Lol.sure :)
> On Dec 4, 2022, at 10:18 AM, Area-51 <goldsteinindustrial@gmail.com> wrote:
>
>
> Thanks, much appreciated... can i have your permission to copy your mod into
the mix?
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=509443#509443
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Message 7
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
My thoughts about altering the retraction geometry; If Ive got it right, your
proposal is to move the bottom pivot (the LG8 pin) forward a bit, albeit on an
arc. My uneducated opinion is that may well reduce the amount of over-centre
of the down-lock geometry to a critically small amount that could lead to the
undercarriage unlocking and collapsing. The amount of over-centre is quite
small anyway; the centre pivot should be 1/16 to 1/8 forward of a line between
the top & bottom pivots. If its less than 1/16the over-centre lock will be
dangerously weak and at risk of unlocking whereas if its any more than 1/8 too
much load will be put on the frame, running the risk of frame damage. IMHO
the original design was developed for very good reasons and does not need messing
around with! If its built correctly and if its then maintained correctly
it should not fail.
--------
G-TERN
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509447#509447
Message 8
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| Subject: | EZ Resolution for Leaking Europa Main Fuel Tank? |
Hi Group
I was getting my Aux. Fuel Tank ready for storage and hatched an idea for an EZ
Main Fuel Tank leak.
I have a 914 XS Mono. I put a 914 pump on tank to transfer fuel.:
https://1drv.ms/u/s!Ah1S270Nwg9VgfUd0NmCXChH71Wo1g?e=eEID73
Here's my knee jerk idea to possibly deal with a Leaking Main Fuel Tank?:
In my case, install a Long Range style tank to the Port side of my Aeroplane, it
could hold a bit more than the Starboard Factory tank? Install a 914 pump on
that tank as well and just plumb into existing system. Then cut access holes
in the seat back to allow storage inside the leaking tank.
True some details to work out, but nothing that I see at first think to be insurmountable.
If running a bit tail heavy, just install the Depleted Uranium spinner!.
I would have an added incentive to do such a thing, I glassed in Balsa per Nev
under door sill to strengthen and have them filled with wires. In addition on
the top of the cockpit module,I also needed to run plus and minus to the other
side of plane. Starboard is + and port is -, and ran to other side of plane with
a thin wide copper Sheet glassed to the top of the Cockpit Module that would
need to be dealt with.
OK, thoughts?
Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509448#509448
Message 9
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Jon, thanks for your thoughts there however needs correcting..
Position of LG08 components are not altered; the over center locking affect on
extension is actually marginally improved.
Pin LG04 is moved slightly rearward and down upon its arc, relative to the opposite
pivot point at LG08. This keeps the rubber spring block assembly outside
of a 90deg arc from LG08 when retracted. If things here cross over less than 90deg
they can jam in the retracted position if the bungee is too tight.
Apart for preventing a possible lock up in the retracted position the operation
of the landing gear is otherwise unchanged. Moving the position of LG04 adds
mechanical advantage at the final end of retraction; which the bungee currently
provides.
The addition of a sacrificial buffer prevents retracting of the undercarriage too
far. The above repositioning of pin LG04 is helpful but not required
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509450#509450
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| Subject: | Re: The Obsidian File - Mono Undercarriage |
Today the numbers on mod-xx were run through the trap. Short story 50% reduction
in component stress and force required at the operator end.
Both factory and mod-xx had the same parameters applied along with gravity to factor
in the torque of the swing arm's mass. LG12 undercarriage lever has been
modelled using 4.0mm 1020 sheet steel.
At close out of the undercarriage retraction the factory setup delivers a 30200
Nm moment from LG08's axis to the operator handle while mod-xx delivers 13600
Nm.
Force required in the X direction (forward moving) at the operator handle for the
factory setup is 700 N while mod-xx requires 320 N.
Tension force required at the bungee to reach zero mass balance at of the L02 undercarriage
arm is 860 N
The assembly model received a vertical force of 100 N at the wheel axle line and
gravity factor... bungee tension was not added to either test model.
This concludes this Obsidian File chapter to further discussion.
Images included for the technically astute.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=509451#509451
Attachments:
http://forums.matronics.com//files/897020e8_3e8b_4de0_9265_44fdeb6a39a8_121.jpeg
http://forums.matronics.com//files/04f209dd_820c_4c78_b33d_1517268f32b4_121.jpeg
http://forums.matronics.com//files/1c44905b_5776_4e1d_ab32_6cc037b6df93_335.jpeg
http://forums.matronics.com//files/fcf28621_34bd_4ecd_80db_76ee499c4ffe_137.jpeg
http://forums.matronics.com//files/c47d328d_72e9_4ebd_9b20_4308e55b0e19_515.jpeg
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