metalman Posted February 22, 2013 Share Posted February 22, 2013 Hi , I'm thinking of rebuilding the landing gear in my Kitfox type with carbon fibre, I've got a bit of experience with fibre glass but was after info on what products to use, the process ,thickness's for given strengths, mounting arrangements, I'd be looking at the tailwheel spring first and if it works out I'll do the main gear as well Met Link to comment Share on other sites More sharing options...
djpacro Posted February 23, 2013 Share Posted February 23, 2013 Next time you visit I will show you some composite landing gears and you can take a peek at my copy of this book: http://www.aircraftdesigns.com/vmchk/Books/COMPOSITE-AIRCRAFT-DESIGN/aircraft.tpl.html (plus pick up that software you wanted) Link to comment Share on other sites More sharing options...
djpacro Posted February 23, 2013 Share Posted February 23, 2013 And I have a book specifically on design of light aircraft landing gear you can look at. 1 Link to comment Share on other sites More sharing options...
metalman Posted February 23, 2013 Author Share Posted February 23, 2013 I'll have to catch up soon, Link to comment Share on other sites More sharing options...
fly_tornado Posted February 23, 2013 Share Posted February 23, 2013 *scratches head* wonders out loud, what's wrong with the factory design? Link to comment Share on other sites More sharing options...
metalman Posted February 23, 2013 Author Share Posted February 23, 2013 *scratches head* wonders out loud, what's wrong with the factory design? Well,,,on one hand we have a whole flock of whiners lamenting how its all about GA or there's no innovators, everyone wants one off the shelf,,,well buddy perhaps I'm not an off the shelf kinda guy, I also rarely waste time on ,,,,,wits so from me pal this is your answer ,back under yonder rock with ya,,,,,,,,,, 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted February 23, 2013 Share Posted February 23, 2013 won't carbon fibre be really stiff and brittle? I can see you bouncing 20' if it doesn't collapse Link to comment Share on other sites More sharing options...
djpacro Posted February 23, 2013 Share Posted February 23, 2013 Personally, I wouldn't use carbon in your application - run some numbers and see for yourself. Link to comment Share on other sites More sharing options...
metalman Posted February 23, 2013 Author Share Posted February 23, 2013 Personally, I wouldn't use carbon in your application - run some numbers and see for yourself. I'll have to look in to it , I'm doing a new panel ,cowls and some components using carbon fibre for the Lobo, I want to get it below the 300kg . The eurofox and the Jabs use GRP gear but I'm not sure what fibre it is , I'm ordering some Berhinger wheels and brakes for it , lighter, sexier and the brakes will actually do something( oh and they come with 26 inch tyres) Link to comment Share on other sites More sharing options...
facthunter Posted February 24, 2013 Share Posted February 24, 2013 Why wouldn't laminates of carbon fibre and other materials make a good undercarriage leg? As far as bouncing any UNDAMPED spring will store energy and give it back later. Those leaf spring undercarriage legs are heavy and quite a few have broken in service. Nev Link to comment Share on other sites More sharing options...
fly_tornado Posted February 24, 2013 Share Posted February 24, 2013 Carbon fibre has been around for a while, you assume that its been tried before... I think the inability to determine fatigue could be an issue. The Tornado uses 1.5" desiccated fibreglass struts which give a lot of spring compared to the alloy and titanium legs that are also fitted. The fibreglass starts to split once its getting old. Link to comment Share on other sites More sharing options...
facthunter Posted February 24, 2013 Share Posted February 24, 2013 My understanding of it's faults? is that it is not suitable for compressive loads . hence the laminate. It's been around for ages in pushbike and motorcycle and race car applications. Quite proven but used to be costly and a bit lethal as to human contact with solvents used. Nev Link to comment Share on other sites More sharing options...
Yenn Posted February 24, 2013 Share Posted February 24, 2013 I was under the impression that carbon fibre is strong, but also stiff. A bit like cast iron, whereas there are better types of glass fibre to use. Somewhere I have an approved drawing for a glass tailspring for the Corby, and it is not carbon fibre. Will have to find it and post it here. 1 Link to comment Share on other sites More sharing options...
facthunter Posted February 24, 2013 Share Posted February 24, 2013 If you want to see how much it flexes watch the dreamliner lift off. I would imagine all high performance gliders use it for stress carrying parts like wing spars etc. If you make a deep box section it will be stiff. It's tougher than old boots. Nev Link to comment Share on other sites More sharing options...
corvairkr Posted February 24, 2013 Share Posted February 24, 2013 The KR2-S uses unidirectional glass.Not a great view but you can get an idea of how much shock absorption is available in this clip. jason 1 Link to comment Share on other sites More sharing options...
metalman Posted February 24, 2013 Author Share Posted February 24, 2013 I'm at the thinking about it stage, I started from the carbon fibre idea as I've seen it used in masts for yachts ,spars, chassis' for race cars and propellers ,,,but it'll also have to be "soft" enough to soak up roughing ground. There's a little bit on the net about it and from what I've seen on one sight http://curedcomposites.com/gear.html They are using woven rovings ,and epoxy resin ,I've got the time so I'll gather as much as I can before going shopping, as I wrote the motivation is weight loss so if it going to be heavier than 4130 chro-mo then I'll build them that way, the berhinger wheels/axles have very different attachments so I'll have to redo the gear either way .another option is Kevlar ,it has different properties to glass or carbon, and is still pretty light. Link to comment Share on other sites More sharing options...
Old Koreelah Posted February 24, 2013 Share Posted February 24, 2013 I'm at the thinking about it stage, I started from the carbon fibre idea as I've seen it used in masts for yachts ,spars, chassis' for race cars and propellers ,,,but it'll also have to be "soft" enough to soak up roughing ground. Carbon is great stuff if you have the gear and skills to achieve a high quality job. Heat and pressure are needed to exclude bubbles and get a good cure. That probably means an autoclave. Yes, it's used on bike frames, yacht masts etc, but these are applications where a trade-off is made between weight and reliability. Yacht racers will risk the odd broken mast for the sake of a win. One pothole could total your aircraft. Link to comment Share on other sites More sharing options...
metalman Posted February 25, 2013 Author Share Posted February 25, 2013 Good point about the trade off between reliability and lightness, does anyone know what cloth is used in the jab gear? Link to comment Share on other sites More sharing options...
Old Koreelah Posted February 25, 2013 Share Posted February 25, 2013 Good point about the trade off between reliability and lightness, does anyone know what cloth is used in the jab gear? Yonks ago when I imported a roll of S-glass, the supplier said that Jabs are built with E-glass; cheaper than structural grade glass, but quite adequate to the task, as all their testing has proven. Link to comment Share on other sites More sharing options...
RickH Posted February 26, 2013 Share Posted February 26, 2013 I never cease to be amazed by the armchair experts so willing to jump in and offer totally uninformed opinions some of you guys really should think before you put your fingers into gear. Try checking out the Carden Aircraft website Carbon fibre landing gear good enough for some of the top aerobatic aircraft good enough for me. Cheap Enough too. RickH Link to comment Share on other sites More sharing options...
Old Koreelah Posted February 26, 2013 Share Posted February 26, 2013 I never cease to be amazed by the armchair experts so willing to jump in and offer totally uninformed opinions some of you guys really should think before you put your fingers into gear.Try checking out the Carden Aircraft website Carbon fibre landing gear good enough for some of the top aerobatic aircraft good enough for me. RickH Rick you may find most aerobatic aircraft are operated from pretty smooth airfields, so don''t need to be over engineered to cope with the rough paddocks likely to be used by the rest of us. Link to comment Share on other sites More sharing options...
RickH Posted February 26, 2013 Share Posted February 26, 2013 The Carden site was used purely as an example do some web surfing there are others and regardless of operational arena there are certain design rules to which all aircraft designers adhere undercarriage stress (impact, fatigue and otherwise) being one of them. RickH Link to comment Share on other sites More sharing options...
fly_tornado Posted February 26, 2013 Share Posted February 26, 2013 Carden Aircraft are R/C... 1 Link to comment Share on other sites More sharing options...
djpacro Posted February 26, 2013 Share Posted February 26, 2013 Carden LG is surely fine for top model aerobatic aircraft. 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted February 26, 2013 Share Posted February 26, 2013 Have you seen how some of those RC pilots ^land^ Link to comment Share on other sites More sharing options...
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