Jump to content

Gert

Basic Member
  • Posts

    10
  • Joined

  • Last visited

About Gert

  • Birthday 09/25/1964

Contact Methods

  • Website URL
    http://avunlimited.co

Profile Information

  • Gender
    Male
  • Location
    South Africa
  • Interests
    All things Aviation
  • Reg #
    ZS-ITO

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

Gert's Achievements

Rookie

Rookie (2/14)

  • First Post
  • Collaborator
  • Week One Done
  • One Month Later
  • One Year In

Recent Badges

29

Reputation

  1. OK, I'll take a bite! The Lord disks were made by an injection technique where the rubber mixture is injected into the mold in a molten state through multiple ports. This method in itself was problematic with surface cooling of each injected "blob" before they had a chance to mix. The composition of the rubber has been such that it did not allow ozone protection or UV protection. The latest composition is a mixture of 80% Natural Rubber and 20% Styrene Butadiene Rubber with good resistance to weathering and Ozone cracking. The maximum continuous service temp is 80 Deg C in air with short term service of 110 Deg C possible. The Lord Rubber mix has a much lower service temp. The manufacturing is also done with the material mix inside the mold before it is compressed to form the Disks. The current composition should outlast the Lord type by many years. UV and Ozone exposure tests have successfully concluded this Best Regards Gert
  2. Hi Members The high shipping cost is driven by the volumetric weight of the discs. The discs weigh but 2.33kg for a stack of 11 but the volumetric weight is 5kg. DHL also slaps on a heavy surcharge during covid times. We are in a Lockdown Level 3 situation in South Africa and strict sanitising protocols apply which also drive costs up. If there are any members with contacts at USPS we might be able to ship to a central drop-off point and distribute internally with USPS. The next batch are being manufactured and delivery will start by 21st June Covid willing. My experience with dealing with USPS was to say the least, like getting my teeth pulled. That being said, I still can keep the cost of these disks at approximately 50% below what is available elsewhere. Members must please look on the AVUnlimited website for the pdf link to download the detailed drawing and instruction sheet. This sheet must be completed, signed and emailed to me. This will answer the FAA Owner Produced Part Regulation, FAR 21.303(b)(2). The original form must then be handed to your AMO as source document. The AMO must then note the replacement parts as Owner Produced in the airframe logbook and attached the form. Members can order their discs in advance as I manufacture in relatively small batches(400 disks) at a time. The stock runs out fast. If any members have questions or queries, please email me at gert@avunlimited.co
  3. Hi We have submitted two sets to two different members that are also AMO’s and they have been tested with good results. The only comment was that my rubbers were approx 2mm thinner than the originals. I have had the moldchanged to accomodate that and we are running tests on the new sets. I expect production to start within a month. best regards Gert
  4. Hi Andy I am offering to provide a set for free to whoever want to test the units. I have been manufacturing units for Beechcraft type aircraft for a while now and have only had successful feedback. I am confident this will be no different. The accelerated wear tests conducted included 10 000 compression cycles in minimum and maximum temperatures under constant UV radiation. The units are unloaded and checked for elasticity every 2000 cycles. It is measured against original size and how long it takes to de-compress as well as final shape and size after a two hour rest period. There are allowable tolerances and compression measurements on the original drawings and the shockdiscs stay well within these at all stages of the tests. I plan to also install a set on a South African Mooney and conduct operational tests. I will let you know the results. The manufacturing process is not by means of molten rubber squeezed into a mold via multi-ports as some other manufacturers do. The problem with such processes are that the rubber discs form seams where the material cools down before amalgamating and could split under load - and also did( Specifically AECI Discs). The manufacturers then published a complicated procedure whereby the discs had to be "baked" overnight in a oven powered by a 100W incadescent lamp and then installed. I use a compression molding- and curing process that molds the rubber disc as a one-piece item with no seams etc. The natural rubber and polybutylene mix has been extensively researched and provides the right shoring degree as per the original specifications as well as superior compressibility and elasticity. Best Regards Gert
  5. I have seen this and it is not a slip or omission and refer you to all other manufacturers detail. You will note that the lettering on all alternative products are inclusive of the M20 models as per my discs and non have it printed on the disc, however Aircraft Spruce also states that the disc will fit a Model C. I have checked this with them and they have confirmed. I have written to Lasar and await their response as well. The Mooney specifications seems to be the same, however I stand to be corrected - if you have information on this, please share. Best Regards Gert
  6. I have now sucessfully manufactured the Mooney discs and they are ready to ship. these discs are much more robust than the original Lord discs as the elastomer/rubber compound is much more stable and will have a longer lifespan. They are similar in design as the Beechcraft type, but of a different material mix. Accelerated ageing and UV tests have been conducted with excellent results. These discs will outlast any other. It is not advisable to paint them as the solvents might damage the compound. Some AMO's spray the discs with silicone before installation as this will assist in reducing abrasion. Visit www.avunlimited.co. Best Regards Gert
  7. Hi Carusoam It certainly looks like something I can manufacture. Karl, if you read this. Could you lend me a new rubber mount for measurements and if you have an old one for destructive testing? It will be fantastic if I can manufacture these for Mooney Mite owners and extend the lives of these wonderful little birds. Blue skies Gert
  8. Hi The rubber compound used in the J-11968-14 Lord disc is an elastomer blend type MX with a deflection of 1.0 inch for 3000lbs for a stack of eight discs. It is a multiple compound product with Natural Rubber and Polybutylene with excellent penetration and adherence to the metal discs. It is approximately 40% stiffer than the Beech J-11968-10 discs that I currently manufacture, but all measurements are exactly the same. I can thus use the same moulds, which will definitely assist to bring costs down. The material composition is such that it is more UV stable and can handle much more deflection cycles than the Lord type. In the past Beech members had to pre-warm the donuts before installation to counter splitting problems and to assist installation when ambient temperatures were low. This is no longer a problem with the material temperature range tested between -13F to 113F and installation is a lot faster as a result. I am in the process to get an STC approved, but this will definitely push up costs as a result. If you need a softer or more flexible disc, why not experiment with the J-11968-10. The static deflection of 4 dash10 discs will be 0.75 inch compared to 0.5inch of the dash14 discs. It will however have a marked difference in dynamic elasticity, I presume. Best Regards Gert
  9. You will be able to peruse the BAC website forums without a subscription, use the search engine and verify that you are not a web robot. I attach herewith an article published by Mike Busch that sets out the owner produced parts regulations quite clearly. When an aircraft owner wants me to manufacture a set of Rubber Donuts he gives me an instruction setting out the quality, composition and precise measurements as per attached document. This document is sent to prospective buyers and they fill it in with their details and any measurements or instructions. I have tested this methodology with FAA and they agreed on the validity and that the process and parts adheres to Section 21.303. The process and parts have been exhaustively tested by BAC members and we have retired FAA personnel as members of BAC who have assisted greatly in this process. I am indeed from South Africa, the small town of Caledon at the start of the Garden Route. OPP Mike Busch.pdf Avunlimited - FAA OPP Rev. A (Retractable Gear Disc) Export PDF.pdf
  10. I have the alternative solution to expensive shock discs! I own and fly a Beechcraft Sundowner 180 and had to replace the shockdiscs. The costs were unbelievably high and I could not believe that such a simple device as a rubber disc can cost so much. I decided to investigate if I can manufacture these discs at a more affordable price, since the FAA allows aircraft owners to produce parts. I found that it is absolutely possible and that under FAR section 21.303(b) I will be allowed to manufacture these discs for other owners as well. About two years ago I started collecting information on the composition and detail of the discs. I manage to stumble onto the original manufacturing specifications of the Beechcraft as well as Mooney discs. The manufacturing data and rubber composition for both discs were made available by a retired engineer from Lord who used to manufacture these discs. The Mooney discs have the same composition as the Beechcraft discs of the natural rubber and percentage Poly-butyl-dye-lean which is slightly more dampened and stiffer. I went ahead and started manufacturing the Beechcraft Landing gear with great success at one third of the cost of similar products. I decided to manufacture the discs at cost + 10% to ensure the extended life of the "Baby Beech" line of aircraft and also to give back to the industry that have given me so much during the past 30 odd years. I also started a website www.avunlimited.co where Beech Aero Club members and other owners can read more and order the products. Profits so generated will be used to train disadvantaged young pilots. I can also easily manufacture Mooney shockdiscs at below $50 per disc and would like to gauge interest from Mooneyspace members in this regard. Please let me know what you think or e-mail me at gert@avunlimited.co.za. You can also visit the BAC website and topic at http://www.beechaeroclub.org/showthread.php/13829-Rubber-Donuts-Now-at-reasonable-prices Blue Skies Gert
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.