---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Sun 12/04/22: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 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 _____________________________________ Time: 02:52:10 AM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Dave Disney" 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 _____________________________________ Time: 04:21:02 AM PST US From: Pete Subject: Re: Europa-List: Re: The Obsidian File - Mono Undercarriage Fwiw, my throttle box serves that same purpose :) > On Dec 4, 2022, at 12:34 AM, Area-51 wrote: > > > Some further thoughts today upon this. > > 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. > > Some photos included. > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=509439#509439 > > > > > Attachments: > > 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 > > > > > > ________________________________ Message 3 _____________________________________ Time: 04:25:56 AM PST US From: Pete Subject: Re: Europa-List: Re: The Obsidian File - Mono Undercarriage 5/8x0.035 > On Dec 3, 2022, at 10:13 PM, Area-51 wrote: > > > Nice solution Peter; what gauge tubing has been used there? > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=509437#509437 > > > > > > > > > ________________________________ Message 4 _____________________________________ Time: 07:11:36 AM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Area-51" 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 ________________________________ Message 5 _____________________________________ Time: 07:21:12 AM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Area-51" 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 _____________________________________ Time: 07:28:33 AM PST US From: Pete Subject: Re: Europa-List: Re: The Obsidian File - Mono Undercarriage Lol.sure :) > On Dec 4, 2022, at 10:18 AM, Area-51 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 > > > > > > > > > ________________________________ Message 7 _____________________________________ Time: 12:14:56 PM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Jon Smith" 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 _____________________________________ Time: 01:23:57 PM PST US Subject: Europa-List: EZ Resolution for Leaking Europa Main Fuel Tank? From: "rparigoris" 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 _____________________________________ Time: 03:52:41 PM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Area-51" 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 ________________________________ Message 10 ____________________________________ Time: 10:57:11 PM PST US Subject: Europa-List: Re: The Obsidian File - Mono Undercarriage From: "Area-51" 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 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/europa-list Browse Digests http://www.matronics.com/digest/europa-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.