EEVblog #604 - Sinclair C5 Restoration - Part 1 - Page 1
Forum section: electronics / general

author: mux
author_rank: Regular Contributor
timestamp: April 17, 2014, 11:10:18 am
content: Failing to see this already being posted, I'll just start the threadDave, you live in the wrong country! Here (Netherlands) we have C5s in excellent shape flooding the second hand market, being offered either for free or for very low prices (e.g.http://link.marktplaats.nl/m798109381). This is mostly because the things are, with all the possible respect towards Sinclair, utter crap. Uncomfortable, impractical, slow, ugly and just generally inferior to every other option. You can get a pretty decent 25km/h electric bike second hand for half the price you paid for your C5 - or a fully functional velomobile for about twice as much. They serve no purpose other than maybe telling some history, but the market here was flooded with them and demand from bike buffs is low, so they're not worth anything. I've seen people shipping them overseas from the netherlands for less than you paid.Anyway, about the restoration. I've seen quite a few people either offering restored/upgraded C5s or offering replacement parts. Things you want to do:Just send the steel frame for sand blasting (if it works the same way down there as here you can get it sand blasted for next to nothing at boat docks, car repair shops and such) and paint it with either lead paint (if that's still around) or a 3-coat primer-car paint-hardcoat. If you don't want to have the hassle of multiple layers, you can also use Tectyl (not sure if that brand exists in AU).Ditch the pedals and chain, entire rear driving assembly (also the fixed axle - it's pretty bad) and rear wheels and replace the rear wheels with single-side suspended wheels from carrier bikes (https://www.google.nl/search?q=bakfiets&es_sm=93&source=lnms&tbm=isch&sa=X&ei=obFPU-iHOcnfPY2WgYgG&ved=0CAgQ_AUoAQ&biw=2560&bih=1293). Around here these wheels are a dime a dozen, Sachs/SRAM makes excellent braking hubs for them, it's just miles better than the crusty old sinclair stuff and you're not able to use the original pedals for anything useful anyway without ruining your legs. While you're busy, canter the wheels inward a little bit; this greatly helps turning stability.Put in a front hub motor. Because it's just a 16" wheel you are probably limited to the small-diameter Shimano hub motors or the entirely spokeless chinese motor hubs. It's probably not worth the hassle to try and make anything yourself here; just buy an entire kit off of ebay. If you do want to make something yourself I'd say you should emulate the german guy who put a 16kW electric motor on his bike and just did burnouts all day(yes please?)The fiberglass is kind of hard to return to its original state. Sanding or polishing will get rid of any weathering, but you won't get the original surface finish. Painting over it is maybe a safer bet, but you do need to prime it and kill the fungus spots (yes, those are fungi)If you care about your back and butt, or about comfort at all, I highly recommend putting in a proper recumbent seat that is much more laid back. The original Sinclair seating position is way too upright to be comfortable - no successful recumbent on the market requires you to fold up *that* much. If you don't want to hack into the fiberglass to make it fit, at least get a 'Ventisit' mat; you can thank me later.I'm not sure about the rules in AU, but here in the NL you need to have a fair amount of minimum safety features on your bike. Reflectors on at least the wheels and pedals, functioning front and rear lighting, a recognizable sounder. I've only been in AU once and you seem to have almost no bicycle paths, let alone other infrastructure to protect yourself from other traffic, so make sure the thing is visible both day and night. A flag is NOT going to help you in any way, it's a tiny amount of surface area moving very quickly, seldomly oriented in the right direction for traffic to see. Reflectors that clearly define the extent of the vehicle and lots of (non-blinking) light is the way to go. Also when driving, demand your own place on the road. Drive in the middle of the road when you need to pass in front of other traffic to the other side so they cannot suddenly pass you while you are maneuvering, clearly communicate your intentions with hand or blinker signals, drive defensively.edit: I'm getting a lot of typical Cloudflare errors by the way - resulting in corrupted edits on my post, database errors, etc.

author: nathanpc
author_rank: Unknown
timestamp: April 17, 2014, 11:15:59 am
content: This will be a very interesting series since Dave will touch on subjects that are not directly electronics-related, but some times (restoration in this case) you need to at least have a general understanding to know where to start.Looking forward to the next part!

author: Wytnucls
author_rank: Super Contributor
timestamp: April 17, 2014, 11:23:55 am
content: Who needs a bicycle path?

author: a4x4kiwi
author_rank: Newbie
timestamp: April 17, 2014, 11:42:36 am
content: A few notes...The switch is not original That looks to be from a power drill.Power switch was under the thumb position on the LH handlebar.Drill holes are for light switchTyres. Get slicks. Look for pram wheels on council clean-up.I have an aluminium from wheel for you already.POR15 is great 'paint over rust' paint. I use it on my cars. Available mail order.Use green 3M scourer and Gumption to clean the body.Surface rust is OK. The chassis can be welded. I know a guy at Kings Park that would likely do it for you. He races electric super-bikes so take your camera.Speed controller if the original one needs replacing. No Problem. Try a Item # SPD-24500B fromhttp://www.electricscooterparts.com/speedcontrollers24volt.html.Schematic here to fix low volt cut-out goo.gl/WddAWQOriginal front wheel was plastic. Melted under heavy breaking. Will drop over the ali one.Giving away my secrets re hub motor. :-) See you at the track.Schematic and manualshttp://c5alive.co.uk/index.php?com=pages&page=5Call me if you want help over the long weekend.

author: max_torque
author_rank: Super Contributor
timestamp: April 17, 2014, 11:44:09 am
content: Looking at the chassis, rust is not your problem! (you have minor surface rust, typical of your warm climate, in europe, our rust would have eaten away that chassis to the point you could break it up with your fingers!) The chassis clealy shows signs of fatigue failure of the spot welds and local material. As you would expect, with years of having a >75kg person bouncing up and down on very thin section steel, the flexure has caused the spot welds to open up, and the material has failed. You will not be able to replace the full strength of the chassis without additional welded in support, but looking at it, adding lazer/waterjet cut re-enforcing steel plates in say 2mm mild steel across the top and crucially the bottom (where the loads try to "Open" the joints) looks to be very easy, and anyone with a MIG welder can do this cheaply (local car repair garages etc)As mentioned, a full strip down, and sand/media blast will clean the metal chassis up and show if there is any serious perforation from the rust before you start the repair etc.The "extra trigger switch and mosfets" looks to be a later attempt at proportional speed control for the drive motor, as it is using a cordless power drill pwm controller (the finger trigger part) wired to that pair of large mosfets (to amplify the max current capability). I expect, when the original thumb "accelerator" switch failed someone tried to bodge that on the bars or the seat baseRegarding the front wheel hub motor, although an easy option, if you want to add more power it will never drive very well because of the castor angle in the steering geometery and the fact that with you sitting in it, and with the batteries in the back, i suspect the mass distribution is so rear biased that the front wheel will spin before you get up any steep hills! (you could sit the car on some bathroom scales and measure the mass distribution to calculate the max tractive effort and gradability with that front wheel hub motor.Personally, i'd go for a pair of high power brushless motors with a high reduction gear modern belt drive to the rear axle myself!

author: EEVblog
author_rank: Unknown
timestamp: April 17, 2014, 11:50:50 am
content: Quote from: mux on April 17, 2014, 11:10:18 amThat's not the point.QuoteI find it impossible to believe you can ship a Sinclair C5 to Australia from Europe for less than what I paid, just for the shipping alone.

author: mux
author_rank: Regular Contributor
timestamp: April 17, 2014, 12:05:17 pm
content: Quote from: EEVblog on April 17, 2014, 11:50:50 amI know it's not, I was just explaining why they are dirt cheap/free around here. Without any practical value and without any collector value... it has no valueQuoteI'm not sure if you can ship it all the way to Australia from here for that price, I only know from people who had a velomobile shipped to Scandinavia, the US and South America. It's done with the same service that Alligt and Velomobiel.nl use to ship velomobiles abroad. Called container drop shipping, it takes ages but you only pay for weight. It's about €200-250 for a velomobile, I imagine around the same price for a Sinclair. That is without a crate though - velomobile manufacturers also tend to put a proper 'flightcase style' crate around it which costs about as much (A quick google around gives me a couple of 10 year old replies where another shop charged €300 for a crate:http://osdir.com/ml/culture.transportation.humanpowered.velomobile/2005-12/msg00065.html).You do have to get it yourself from the freight port, otherwise you pay through the nose to have it couriered to your home.The high price on that forum thread is mostly down to customs fees and VAT on a €7000 bike. The actual shipping itself is a diminutive amount compared to the total price.

author: david77
author_rank: Frequent Contributor
timestamp: April 17, 2014, 12:33:53 pm
content: I wouldn't worry too much about the rust, from what you can see in the video it doesn't look too bad. Have a look at the underside of your car and you'll find it looks much the same.The split middle bit of that Y frame is a worry, though. That's cleary something you need to take care of. I suspect there's a fair bit of welding to be done to fix that. Every car mechanic should be able to fix that.The first thing to do is to take the whole bike apart to assess the damage to that frame, I reckon.

author: EEVblog
author_rank: Unknown
timestamp: April 17, 2014, 12:44:26 pm
content: Quote from: mux on April 17, 2014, 12:05:17 pmThat's AU$370, and suspect it would actually be a lot more than that.

author: dr.diesel
author_rank: Super Contributor
timestamp: April 17, 2014, 12:50:33 pm
content: Dave, next time you're in Indiana I'd be happy to weld that up for you!

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 17, 2014, 01:12:37 pm
content: Looks like you could whip up a new chassis with some RHS on a saturday.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 17, 2014, 01:16:36 pm
content: I wonder if a front hub motor might struggle with grip, as there wouldn't be as much weight over it as with rear drive.

author: ElectricGears
author_rank: Newbie
timestamp: April 17, 2014, 01:41:36 pm
content: Once you get the chassis free, look into electrolytic rust removal, it should be right up your ally. It can be re-welded (and reenforced) where it splitbut stop sitting in itor the box section might just peel open all the way down the bottom seam and buckle which will make it a lot harder to fix. Get it powder coated when it's done.

author: G7PSK
author_rank: Super Contributor
timestamp: April 17, 2014, 02:50:11 pm
content: That chassis is made from production steel, its like puff pastry made from rolling sheet steel and lead upon itself multiple times, it was very popular at the time of production of that C5 for car panels as it was very easy to deep draw in presses as the lead layers self lubricated the steel and allowed for deep pressed sections. The problem was it is hygroscopic due to the lead and steel layering it is rusting before use which is why cars of the period were such rust buckets ( I remember seeing piles of steel sheet outside of Fords Dagenham uncovered and soaking up the rain waiting to go into the press shop). If you look at the seam of the chassis near where it forms the Y you can see the rust pushing the two half apart on the spot welded seam, that is going to need cleaning up and plating, and weld shop or garage should be able to do that.

author: koitk
author_rank: Newbie
timestamp: April 17, 2014, 04:20:57 pm
content: Seems to be cool project, specially when I'm in the process of building electrically assisted bicycle.So I will be keeping an eye on yours.

author: tealsuki
author_rank: Contributor
timestamp: April 17, 2014, 05:51:07 pm
content: I'm sure Ed Aussie50 could give you a hand with the metalwork side of it. He's not terribly local but he works at (a machine shop?) and he's real good with that kind of stuff. Plus he loves your blog!

author: open loop
author_rank: Regular Contributor
timestamp: April 17, 2014, 05:54:25 pm
content: Awesome project would love to see how this turns out.. Go for it !In the early 90's I was into cars so I learnt to weld, if you are planing to weld yourself my advice is to get a decent welding mask and not the crap cardboard thing they throw in with the welder! Take it from me "arc eye" is not funny.That rust is not too bad my old 1970 mini had way more rust! As already suggested get it sand blasted and then weld it up with steel plate. The only thing to watch with welding is that the geometry of the frame is not distorted. Just take some measurements before and take care, practice first though. Or leave the frame repair to a bike / car shop that does body work.I assume you are using lipo batteries... when going down the hills you could use the motor as a dynamo to put some charge back into the battery plus controlling the descent.Being an engineer I am sure you will approach this in a methodical way, this will take a bit of perseverance at least it's easier than scratch building a full size electric car. I also think you need power from the rear as you may suffer a loss of traction on the front.

author: pickle9000
author_rank: Super Contributor
timestamp: April 17, 2014, 06:27:29 pm
content: The trigger from the hand drill is probably for a variable speed motor control.I think you need a friend in an autobody shop, or with a local maker group. You will need a bit of welding but the rust looks pretty minor.As for welding, a little practice and I'm sure you'd be great. I find most people can run a simple bead in 30 minutes.

author: SeanB
author_rank: Super Contributor
timestamp: April 17, 2014, 07:24:30 pm
content: Russian steel strikes again. My father bought an Alfa, and as far as we could tell ( he was an automotive engineer) it was made from compressed rust. The right time frame for that hot rolled steel that had so many rolled in slag impurities that it would rust even under paint. Solution after you have finished reinforcing it is to seal it with boiled linseed oil, diluted 50% in illuminating parffin and sprayed inside the box sections, and painted on a thin film outside, followed by a 2 week stay in the sun to allow it to drip mostly out. Messy, but I bought a Mazda with a little rust on the panels barely starting to bubble through, and did this to it, and left it in the garage with cardboard under the sides to collect the drips. When I sold it 10 years later, after having driven it to the ocean and the dam with a boat, launching with it going in the water on a slipway, the little bubbles were still there and no bigger.As to the Sinclair GRP body, first thing is to wipe down with a solution of household bleach and water 50/50. Do this outside after removing all steel parts, and tape over all decals you want to keep. Use good gloves as well. Then rinse and dry. To clean the badly degraded GRP use a cloth and household scouring powder ( I used VIM, should be a similar white powder there in AUS from Lever) to remove the degraded top surface. Then use car burnishing paste, which you get from your local motor paint supplier, to buff the remaining surface to a shine. Then wax and polish with real car paste wax. Works a charm.Plastic go get some Dash 20 silicone polish, used for detailing cars, and wipe over. You can do everything with this including the GRP, but note it makes it slippery, and a seat done with this has absolutely no friction. I went for a few swims with this, but the boat looked great and looked like it came off the showroom floor. If you want I will decant around 500ml and post it to you, as I buy it in 5l bottles, and it last a really long time.

author: Rutger
author_rank: Regular Contributor
timestamp: April 17, 2014, 09:46:25 pm
content: The frame is split and needs replacing, I would take the frame out and have it replicated in Aluminium for weight and it doesn't rust any more. Think DeLorean.I would also remove all the electrical stuff and start fresh with a newer motor.

author: sleemanj
author_rank: Super Contributor
timestamp: April 18, 2014, 12:09:14 am
content: Quote from: Rutger on April 17, 2014, 09:46:25 pmIt just needs a guy good with a mig welder and a little steel plate, fix that split right up.Making a one off aluminium frame would be ridiculous, hate to think what it would cost, vs a few minutes of a welder's time.

author: Corporate666
author_rank: Unknown
timestamp: April 18, 2014, 04:53:51 am
content: Quote from: Rutger on April 17, 2014, 09:46:25 pmAluminum is generally bad for frames because it won't bend and flex like steel will... the aluminum just fatigues and cracks. You can work around it through engineering and design, but it would be really expensive and possibly not much weight saved when all is said and done - plus quite expensive I would guess (even just for materials alone).Stock fame looks pretty decent to me - sandblasting and welding should fix it.Too bad you aren't closer dave, I have everything you could imagine here at the shop to fix that puppy right up. Hell, we could machine custom parts for it just to say we didIf there's anything I can do, I'm happy to help.

author: miguelvp
author_rank: Super Contributor
timestamp: April 18, 2014, 05:12:14 am
content: Quote from: Corporate666 on April 18, 2014, 04:53:51 amI'm happy with the aluminium chassis in my car weighting just 150 lbs (68 kg).But they use "glue" and rivets to put it together same as aviation frames. Only thing bad about aluminium is that it corrodes with salt water easily, you can conform coat it or just move away from the coast.

author: Towger
author_rank: Super Contributor
timestamp: April 18, 2014, 06:25:35 am
content: Ozzie rust... That's not real rust...Think of it as a starter project, can be bigger ones to some...

author: sleemanj
author_rank: Super Contributor
timestamp: April 18, 2014, 07:02:15 am
content: Quote from: mux on April 17, 2014, 11:10:18 amPurely out of interest, what planet are you from?Dave paid, according to his video, about $200 AUD (one assumes, but close enough to USD to be the same) for his C5, that's 135 Euro.I can not believe that even in the cycling nirvana of The Netherlands you could get a good functioning electric bike for half (what, 70 EUR), or any sort of Velomobile in any condition for 300 EUR.Velomobiles, at least with any sort of enclosure you could compare to the C5, are several thousand euro new, I can't imagine much cheaper used (if you can even find one, you don't have a hope in hell of finding a used Velomobile anywhere outside Europe).

author: Tothwolf
author_rank: Regular Contributor
timestamp: April 18, 2014, 07:11:08 am
content: These links might be of use for your rebuild project:Novus Plastic Polishhttp://www.novuspolish.com/Enersys Cyclon Batterieshttp://www.enersys-asia.com/downloadarea/download.asp#cyclonhttp://www.enersys.com/Cyclon_Batteries.aspx?langType=1033On the bicycle side of things, you might also check these out:Sheldon Brown - Bicycle Technical Informationhttp://sheldonbrown.com/articles.htmlZinn & the Art of Road Bike MaintenanceLennard ZinnISBN 1-934030-98-8Zinn & the Art of Mountain Bike MaintenanceLennard ZinnISBN 1-934030-59-7The Big Blue Book of Bicycle Repair (Park Tool BBB-2)Calvin JonesISBN 0-9765530-2-3The Bicycling Guide to Complete Bicycle Maintenance and RepairTodd DownsISBN 1-60529-487-XThe Bicycle WheelJobst BrandtISBN 0-9607236-6-8...and if you want to getreallyserious ($$$) about bicycle repair manuals, you'll find these books on a seasoned bicycle mechanic's bookshelf:Sutherland's Handbook for Bicycle Mechanics 7th EditionHoward SutherlandBarnett's ManualJohn BarnettISBN 1-931382-29-8

author: ToughBookMikey
author_rank: Newbie
timestamp: April 18, 2014, 07:36:04 am
content: Hi Dave:Looks like an interesting, challenging and expensive project. Most of what I was going to say has been said already but I'll just say some of it again. That trigger switch with all of the wires and transistors is a variable speed, reversing speed control from a cordless drill. I've thought of using one for a similar project but I've never been able to acquire everything necessary to even begin to build any of the electric vehicles I have in mind (everything is so expensive and for a disabled parasite like myself who can barely survive there's just not much chance I ever will), but I would certainly do it better than that (wiring and layout wise and what not) if I could do it at all. Also that chassis appeared to be in really bad condition (from what little I could see on the small video), and if I had the kind of resources you do I would try to get it de-rusted in an acid bath and then repaired and then electrolytically plated (so it would get inside and out) with another metal such as nickel or tin or zinc or any number of things and then have it powder coated and then dipped in the best paint you can find (again to cover the inside also). And I also don't think a front hub motor is a very good choice (especially on hills). I'm not a fan of hub motors at all but if you have to use them I think you should put it/them on the rear. I think the most efficient design would be a very high RPM permanent magnet (preferably rare earth) brushless motor mated to a continuously variable automatic transmission. Did I mention I want to build my own electric vehicles?

author: digital
author_rank: Contributor
timestamp: April 18, 2014, 09:34:38 am
content: Dave most of the work to be done in restoration could be done by the average handyman,the motor will have to conform to the Australian regulations in regard to power output in Watts.The biggest obstacle will be time and not losing interest in the project

author: Wytnucls
author_rank: Super Contributor
timestamp: April 18, 2014, 10:05:04 am
content: Dave doesn't strike me as a consummate handyman.Take the wreck to someone competent who can take care of the mechanical side in a short time and concentrate on what you really enjoy, its electrical systems.

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: April 18, 2014, 04:22:53 pm
content: Some take their C5 a little further than gearing it up.. way further...and some further away from pedals to the spaceage.This is awsome...http://www.jetpower.co.uk/c5_media.htmhttp://www.jetpower.co.uk/c5/media/avon_c5.wmv

author: Refrigerator
author_rank: Super Contributor
timestamp: April 18, 2014, 05:25:41 pm
content: Can't wait to see some big ass brushless outrunners with some huge LiPo packs and an enormous electronic speed controller in it.Ps: that rust will come off pretty easily with some sandpaper and you can fill that crack with a welder, after all that you can sand and repaint it for some more longevity.

author: koitk
author_rank: Newbie
timestamp: April 18, 2014, 05:51:15 pm
content: Quote from: miguelvp on April 18, 2014, 05:12:14 amOr you can just use 6000 series aluminium alloy, wich is the one they use to make yachts and boats. Its nicely weldable also. Dave isn't probably not going to rebuild his frame to aluminium, so its kind of offtopic. Anyways the fatique cracking of aluminium, its just matter of stress in the material, if you dont exeed the limits it won't happen. If you stress the material over the fatique limits it will crack after number of cycles, but it will have same results when you would overstress the steel (for example you can take steel wire and bend it number of times and it will form a crack and brake).

author: Refrigerator
author_rank: Super Contributor
timestamp: April 18, 2014, 06:01:09 pm
content: Quote from: koitk on April 18, 2014, 05:51:15 pmAlso, there are different types and alloys of aluminum.

author: ckm
author_rank: Contributor
timestamp: April 18, 2014, 10:31:37 pm
content: It's actually in great shape for a 30yr old vehicle that's been sitting outside. I restore old cars and most of them are far worse than this...Most of what you see is dirt, get some Simple Green and a bunch of rags - most of it will come off. For the plastics, do some research on how people clean C5's - there's probably a standard set of chemicals & tools.As for the chassis, as others said:Sand blastRe-weld broken areas, might need some extra metal, but a decent fabricator will figure that out...Powder coat - don't bother with paint, makes a messBUT, you don't want to do any of this yourself. Find a good local metal fabricator, take the chassis to them and ask for it to be repaired & powder coated. They will have the equipment and/or contacts to get it all done.As for the rusted bolts, after cleaning, spray them with bolt loosener (we use PB Blaster here in the US, make sure what you use is specifically for loosening rusted bolts) and let it sit for a few days. A sharp hammer blow to the bolt or nut can help loosen things - don't hit is so hard that you do damage and use a punch if it's hard to swing.Make sure you buy a decent set of tools to work on this, nothing like bad tools to make the job harder.

author: ckm
author_rank: Contributor
timestamp: April 18, 2014, 10:39:51 pm
content: Quote from: miguelvp on April 18, 2014, 05:12:14 amAlthough it's off topic, you can actually design much stronger, stiffer and lighter car chassis using modern high-strength steels. One of the main issues with aluminum is that it cracks when formed, which is why the chassis in your picture is made up of basically straight edges, flat planes and extruded pieces. In general, this design limitation can cause real issues, particularly when trying to design deformation zones for crash protection. Most of the Tesla Model S is steel for this very reason.I would note that this was not true when that chassis (a Lotus Exige, I'm guessing) was designed more than 15 years ago. You would not design a car like this today, the cost of production would be excessive except in very, very small numbers.Besides, the Lotus Elan chassis is a better example of something similar to the C5, it's steel and it's even lighter than the Exige:

author: ToughBookMikey
author_rank: Newbie
timestamp: April 19, 2014, 01:54:12 am
content: Quote from: ckm on April 18, 2014, 10:31:37 pmI agree with most of that except for the PB Blaster, I'm also in the U.S.A. and I've tried many things (being disabled and incredibly poor I have to fix everything myself) and the best thing I've found is Howes Lubricator (web:http://www.howeslube.com/multipurpose.php) their claims are accurate and I've also found it to be the best lubricant for bushings, I've been able to get a lot more life out of bushings which were already basically shot (though I do wish manufacturers would just stop using bushings, a bushing is always going to be the first thing to fail and they are much less efficient). Howes is hard to find, I finally got my local Napa (auto parts store) to get it and it's less expensive than just about anything else. I've even tried what must be the most expensive stuff (which I got from a free trial) which is Kroil and it was useless, it didn't meet any of their claims. So if you can possibly get Howes lubricator I would highly recommend it (and no I don't get paid for saying that, but as often as I recommend it to people I wish I would get paid for it). Also they used to have the worlds best cap design, it had a straw holder on the side of the cap so the straw was oriented with the side of the can and you could hold the can and straw in one hand, pull the cap off and snap it on the bottom of the can then mount the straw and use. But for some stupid reason they got rid of that design and went with the stupid design of having a straw slot across the top of the lid where if you try to store it that way it takes up a lot more space and your almost guaranteed to lose the straw.

author: Corporate666
author_rank: Unknown
timestamp: April 19, 2014, 02:31:51 am
content: Quote from: miguelvp on April 18, 2014, 05:12:14 amThat would fall under "you can work around it through engineering and design".Fatiguing and cracking are major problems with aluminum frames, especially in things like bicycles, custom motorcycles and custom cars where the people doing the 'design' and fabrication don't really understand much about engineering/design. You can overbuild the hell out of it and likely be safe - but that kills the weight advantage. And at the end of the day, I don't think the frame Dave shows on his C5 is very heavy, certainly not worth the cost of designing something in aluminum when that one can so easily be welded and fixed.

author: Corporate666
author_rank: Unknown
timestamp: April 19, 2014, 02:42:36 am
content: Quote from: koitk on April 18, 2014, 05:51:15 pmNot true. Fatigue cracking of aluminum happens due to loading/unloading of stress. There is no limit that you can stay below such that it won't happen. There is a threshold for steel/iron and titanium... they have a fatigue limit which, if you stay below it, you can apply those forces and have unlimited loading/unloading without failure. Not so with aluminum - it will eventually always fail even with small loads applied. It simply doesn't have the "springiness" that steel and titanium have.You can engineer a stressed aluminum part such that the stresses involved are so far below what the part can take that the time to failure is far beyond the lifetime of your part, but with steel, if you are below the limit, the lifetime is essentially "forever".I agree - this is going way off topic, but I think for Dave's C5.. the only way to work in aluminum is either to do some serious engineering, or overbuild the shit out of it so the lifetime of the frame would be way beyond the lifetime of Dave... but that eliminates the weight savings partly or wholly, and costs metric craploads of $$.

author: ToughBookMikey
author_rank: Newbie
timestamp: April 19, 2014, 04:24:24 am
content: Well if he were to change the frame (which I think he said he didn't want to do), I would recommend Titanium. The price has been coming down (I've heard it's even cheaper than Aluminum) and it's far superior in pretty much every way to steel or aluminum. It's lighter, stronger and less corrosive.

author: opablo
author_rank: Regular Contributor
timestamp: April 19, 2014, 09:22:35 am
content: QuoteWow... so... what about airplane wings ? they flex a lot and I though they were made of aluminum... Are you telling me that airplane wings have a stress-life-span ? ... or maybe the inside of the wings are a steel structure covered by aluminium panels ?... or in aerospace industry they use a kind of aluminum that has a stress-safe threshold ? Don't scare me man...

author: SeanB
author_rank: Super Contributor
timestamp: April 19, 2014, 10:42:14 am
content: Aircraft wings have a definite fatigue life, and will need replacing of the main spars at a defined number of flight cycles so as not to exceed the fatigue limit. As well they are inspected regularly on minor services to ensure there are no cracks that will grow into a break. Typically they have the panels covering the root as a removeable part so that inspection is simple, but at a major service the whole wing will be ultrasonically or dye tested to check for fatigue. As well many aircraft have a G meter to measure stress loads during flight, and if the highest limits have been exceeded x number of times it will go in for fatigue crack detection irrespective of flight cycles or hours.It takes a while to prep the metal for inspection, starting with cleaning it with detergent, stripping down to bare metal with paint remover ( and no sanding of the surface allowed or sand blasting as this may cover cracks) and then using either penetrant dye or an ultrasonic tester to check all through the surface and the inside. Sometimes the parts are X rayed as well to see internal flaws.The fatigue inspection is also applied to the engines, as they also suffer from fatigue.That is why you see many aircraft scrapped and why Jay Leno has so many jet powered cars, as the airframes cost more to check than the plane is worth, and the engines are in need of crack checking which can cost more than a new one, even if it may run for hundreds of hours more before it breaks. You do not want an engine to fail at max power, as you typically are in a takeoff and will crash as you have V1 and not V2 or are too low to abort around. in either case you make a big hole and burn in it.

author: Wytnucls
author_rank: Super Contributor
timestamp: April 19, 2014, 11:23:12 am
content: Most aircraft with spar corrosion get scrapped, as they're too expensive to fix.Wings do fail on old aircraft, so proper inspections are essential.Engines are less critical, as on twins or quads at least, a safe take-off or an abort are possible after engine failure.

author: twotires
author_rank: Newbie
timestamp: April 19, 2014, 08:36:48 pm
content: Hi Dave,My first post, so, thank you for the EEVBLOG! I enjoy the heck out of every episode.The rust on your C5 frame is not so bad. Wire brush / sandpaper it, repair the split, then brush on a liberal coat of POR15 and it should hold up nicely for at least 30 more years. I would suggest boxing in the entire frame, but that would probably add too much weight.The split just needs a triangular gusset fitted and lap welded over the existing steel.Get a used wire-feed MIG welder off ebay (maybe a teardown / repair video on it first, then use it) - you'll be surprised at how useful they are and quite easy to learn. You can use the flux-core wire and don't even need a gas bottle attached.There's an open source DC motor controller project called 'Open Revolt'. You can build the digital part and connect it to a customized power section for any voltage / amperage you need. I built one to handle 100V and 400A DC for about $400 USD. One day, it will push a 1965 VW Beetle.Looking forward to more C5 updates!Michael

author: SkyMaster
author_rank: Frequent Contributor
timestamp: April 20, 2014, 02:44:39 am
content: I would suggest to remove the C5 frame rust by using theelectrolysis rust removalprocess; this would be appropriate for the EEVblog

author: Tothwolf
author_rank: Regular Contributor
timestamp: April 20, 2014, 06:57:58 am
content: Quote from: SkyMaster on April 20, 2014, 02:44:39 amHow would you solve the issue of hydrogen embrittlement though?The overall size of the frame would require a rather large tank and power supply to clean it using electrolysis, and then would be too large to bake in a conventional oven to drive out any hydrogen. Because the frame itself is made of thin sheet stamped and formed into a frame, I'd be hesitant to electrolytically clean it anyway, since hydrogen embrittlement tends to be more of an issue with thin materials than it would be with say a frame made from tubular steel stock.The fumes from electrolysis cleaning are also hazardous, and this isn't a process you can do indoors without special ventilation (and certainly not in Dave's lab). To electrolytically clean the frame, Dave would likely have to outsource the work to a third party, which could be cost prohibitive for a small project such as this.If the steel alloy used for the frame contains lead (as suggested by others), that too would preclude the use of electrolytic cleaning, since the same process used to remove the rust would tend to leach the lead out of the steel alloy, weakening it.

author: alecw35
author_rank: Newbie
timestamp: April 23, 2014, 10:27:24 am
content: hello folks. My first post on here. Ive been watching most of the videos. Ive been interested in electronics, bikes and machines for years. Used to get the electronics magazines in the late 80s, they had loads of adverts. Some of the electronics surplus shops had Sinclair C5 parts for sale. Wheels, tyres and electric motors. I got some wheels and tyres and used them on weird chopper bikes I was building.The tyres had a ribbed tread pattern, for lower rolling resistance, smoother ride so more efficient use of power, and more comfortable. Think the tyres were Sinclair branded V rubber brand. Small wheels and sitting in the "recumbent" position can be a bit of a pain after a while, in parts of the body, you dont want to be painfull.Wheel/tyre sizes were 12" and 16". think they were 2" wide. Those sizes are common on kids bikes, folding bikes, kids scooters, and those 3 wheel baby cart things. think the front wheel on Daves C5 is from a kids bike or cheap baby cart. Better getting an alloy rimmed wheel on there. Probably from a baby cart. As rusty steel rims will just eat through brake pads, with little stopping power. Also cheap steel rims from little bikes are often badly made, not terribly round, and not a constant width. Wheel rims are made by rolling up an extruded U section, then theres a join. On steel wheels this is welded. On cheap rims its badly ground down. So making it narrower for a little bit. So that is felt thru the brakes, hurts your hand, might cause noise or wheel lock up.Heres a video of, Chris Barrie Britain's Greatest Machines - S01E04: 1980s - The Future Has landedChris has a try in a C5. Shows the bare frame and some other parts. He also has a go in a Delorean, a Lotus, tanks and helicopters. Lots of things that any bloke would love to play with. Chris Barrie was in the Red Dwarf sci fi show. He was also Angelina Jolies butler on the Tomb Raider movies. As Ive said, lots of things that any bloke would love to play with.....meaning the big robot and cars and gadgets.

author: electrolux
author_rank: Regular Contributor
timestamp: April 24, 2014, 01:17:31 pm
content: Quote from: twotires on April 19, 2014, 08:36:48 pmThat's exactly what I wanted to say, but if you cant get the welder you could get a piece of 2mm thick sheet of metal bend it and pop rivet it to hold the split together, rather crude but a last resort, but I still highly recommend a welder, and welding is easy see

author: Smatek
author_rank: Newbie
timestamp: April 26, 2014, 08:08:08 pm
content: This is a very interesting project.The chassis ask the boat people. They know all about fiber glass materials and repair. Some tips were already have been given.With the rust, that is no problem. You can use the oxalic acid C2H2O4 or Phosporic acid H3PO4 to remove. You can write to me for further questions.To protect and paint Company Owatrol is the first choice!Have a look:http://www.owatrol.com/index.php?langue=en&page=produits-rustol-owatrolIt is used by german army.The engine -> a big hub motor with at least 800W in the front wheel.The electronics - think about energy recovery.One of the 48V 10AH LiFePO4 Battery Packs, about 10kgFor braking the best german product, Magura HS-33 hydraulic rim brake. Install and forget - this system ist wokring for time decades! And a rim brake works at the point where the force occurs. and you can use radial Spokes.http://www.magura.com/en/bicyclecomp/products/rim-brakes/hs-33.html

author: ToughBookMikey
author_rank: Newbie
timestamp: May 03, 2014, 03:07:39 am
content: Quote from: alecw35 on April 23, 2014, 10:27:24 amThanks alecw35 for that link. Interesting show.

author: electrolux
author_rank: Regular Contributor
timestamp: May 04, 2014, 02:31:18 pm
content: I'm looking forward to part 2

author: alecw35
author_rank: Newbie
timestamp: May 21, 2014, 09:37:20 am
content: maybe Dave should test a modern electric assisted bike. To see how it goes and how the engineering compares to way back then

author: alecw35
author_rank: Newbie
timestamp: January 09, 2015, 08:10:25 pm
content: http://en.wikipedia.org/wiki/Sinclair_C5Hey its the 30th anniversary of the Sinclair C5s launch.maybe time for another video on it

author: djos
author_rank: Unknown
timestamp: December 01, 2016, 09:00:48 am
content: Argh no part 2, Dave!Ps, here's the gold standard in C5 upgrades, imo of course....https://youtu.be/EZX_16OojKk