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Citroen 2cv pages

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Re: Citroen 2cv pages

#71

Post by lokedhs »

adhesive_wombat wrote: post #34

Not car-specific but I do miss the days of huge paper catalogues. The multi-volume RS ones were great, but the real joy was something arcane like an optics, RF or connector company. I was convinced to throw away my relatively small and likely valueless but prized collection to well-intentioned "decluttering" when I moved to my own house. The thing is, they actually did spark joy, as Marie Kondo would say. Also data b…

I remember reading the data sheets for various computers, like IBM or Sun machines. I later worked for Sun, and I think those data sheets is one reason I joined.

Surely someone must have collected scans of these data sheets somewhere? I'd love to look through some of them again. There is some on bitsavers, but I'd like to see some more.

Re: Citroen 2cv pages

#72

Post by adamjb »

RicoElectrico wrote: post #67
morninglight wrote: post #66

Earlier quoted context omitted.

The 2CV was inexpensive and indestructible. It was perfect for 3rd world nations that the French had colonized. The 4 wheel independent suspension could go over worse potholes on unpaved roads than you have ever seen. And if something did break, you could either fix it with a coat hanger or find a nearby shade tree mechanic with enough experience to get the job done. I fell in love with it back in the '60's and wante…

Interesting, I've seen my friend post a video not long ago with a 2CV in shot, that was in Paris. You'd think France as the Western Europe would focus more on safety and emissions (apparently French are very climate conscious).

2CV's do around 6L/100km which is comparable to modern town cars

Re: Citroen 2cv pages

#73

Post by RalfWausE »

sbarre wrote: post #58
amelius wrote: post #38

They should really make a modern retro version of the 2CV, like they did with the MINI and VW Beatle. It's such an iconic car.

Wonder if they could make an electric version of the wagon? It could be great as a short-haul utility/delivery vehicle...

Now... my parents have this for driving around town:

https://elektrofrosch-berlin.de

I think its a good successor of the spirit of the 2cv

Re: Citroen 2cv pages

#74

Post by kragen »

I was thinking about the 2CV the other day with respect to drone motors and rollerblades.

A 75%-efficient 1000-watt 20000-rpm quadcopter motor is one horsepower, costs about US$150, is about 50 mm in each dimension, and weighs 250 g. If you couple it to an 8-mm-diameter output shaft, the shaft's surface speed is 8.4 m/s or 30 km/hour. Hook up a 10 cfm cooling fan to remove the 250 watts of heat (the other 25%), mount the shaft between sprung two ball bearings that press it up against a rollerblade wheel, and you have a one-horsepower roller skate.

An average human can wear two such skates at a time, thus providing deux chevaux of power, 1500 W, which is 180 N (the weight of 18 kg) at 30 km/hour or 1100 N at 5 km/hour, plenty of power to burn rubber. Accelerating a 100-kg human to 30 km/hour requires 3.5 kJ, 2.3 seconds at two horsepower, limited in practice by traction. Most of the time you would be using much less power than that, and of course you need active traction control so you don't burn rubber every time you pick up your foot and put it back down, but this seems like a tractable engineering problem.

If your average net power usage (losses to air resistance, road roughness, rolling resistance, and round-trip losses from regenerative braking) is 100 watts, a two-hour trip is 0.7 megajoules. This is considerably lower than the average power usage of a Citroen 2CV because a human has a lot less air resistance than a car, even with a helmet and kneepads.

You could provide this energy with 1.9 kg of lithium-ion batteries in a backpack, costing about US$300, but plausibly you could make it cheaper by using high-discharge-rate lithium cells for half or a quarter of that (US$75 or US$150) and US$40 of deep-cycle lead-acid batteries (4 kg) for the rest.

The "2CV" in the car name was kind of a tax fraud, though. An actual Citroen 2CV offered 9 horsepower even at the beginning and 29 horsepower by the end, which is a lot more than you can strap onto your feet even with modern drone motors.

On the other hand, if you used a larger shaft, you could get the skates to go a lot faster than a 2CV could. But I'm not sure that would be a good idea.

Re: Citroen 2cv pages

#75

Post by masklinn »

kragen wrote: post #74

I was thinking about the 2CV the other day with respect to drone motors and rollerblades. A 75%-efficient 1000-watt 20000-rpm quadcopter motor is one horsepower, costs about US$150, is about 50 mm in each dimension, and weighs 250 g. If you couple it to an 8-mm-diameter output shaft, the shaft's surface speed is 8.4 m/s or 30 km/hour. Hook up a 10 cfm cooling fan to remove the 250 watts of heat (the other 25%), mount…

> The "2CV" in the car name was kind of a tax fraud, though.

It was not, the taxable horsepower and the “actual” horsepower are completely different things, as the former is derived from displacement (and / or gear speed at a fixed rpm). There was no fraud because this was how it was expected to work.

Re: Citroen 2cv pages

#76

Post by jacquesm »

Svip wrote: post #70
jacquesm wrote: post #43

Earlier quoted context omitted.

Green. It was one of the latest made (1974). I've done plenty of really long trips with it (many thousands of km), but I did replace all of the accessible high pressure LHM tubing at some point to get rid of the periodical 'Arret!' light on the dash because the system lost pressure. I can also tell you from experience that trying to drive a DS without pressure is both an art and a body building exercise at once. Xant…

My mechanic also tells me I'm fortunate that my DS is a five speed manual. No semi-automatic gearbox for me. Also makes the engine bay a lot more accessible (although it is injection). So far, I've replaced the headgasket, cylinders, water pump and injection distributor (with one that achieves lower revs in neutral). The engine repairs were substantial, since water had leaked into one of the cylinders, but it was pos…

Activa V6 is amazing, those are super rare to begin with and I've only driven one once. Cornering in that thing is the weirdest experience initially and afterwards every other car except for high end sports cars feel 'off'.

DS with a five speed manual is the best combo, keep an eye on your steering housing (those tend to go slowly but failure is potentially catastrophic) and front carrier arms, the bushings will wear out and then you'll start to eat tires. Other than that, your main enemy is chassis rust, everything else can be fixed.

Re: Citroen 2cv pages

#77

Post by jacquesm »

jet_32951 wrote: post #68
jacquesm wrote: post #43

Earlier quoted context omitted.

Green. It was one of the latest made (1974). I've done plenty of really long trips with it (many thousands of km), but I did replace all of the accessible high pressure LHM tubing at some point to get rid of the periodical 'Arret!' light on the dash because the system lost pressure. I can also tell you from experience that trying to drive a DS without pressure is both an art and a body building exercise at once. Xant…

That sound from the Citromatic used to be called 'boinking' and it is inescapable unless the fluids and seals are up to snuff. Citroën hydraulics are detailed but not that complex, patience + Viton aftermarket seals (green fluid = hexylene glycol) are your friends. Agreed that the ID (idée)-19 had a lot of advantages from its simplicity.

> Citroën hydraulics are detailed but not that complex

Have a look behind the left hand front wheel cover panel and say that again :) There has to be at least 50 meters worth of high pressure line behind there and a functional analog computer using hydraulics. That's what keeps the car balanced front/back and left/right. The height adjusters just do the static balancing for load, that thing on the left front does it dynamically with a response time in the 10's of milliseconds and keeps continuous track of what 'level' means to the car occupants. It is a very impressive piece of engineering which has some components that will leave you completely puzzled (a tube with a few hundred metal plates in it with a tiny hole through the middle, for instance) if you don't know what they are for.

Re: Citroen 2cv pages

#78

Post by kragen »

masklinn wrote: post #75
kragen wrote: post #74

I was thinking about the 2CV the other day with respect to drone motors and rollerblades. A 75%-efficient 1000-watt 20000-rpm quadcopter motor is one horsepower, costs about US$150, is about 50 mm in each dimension, and weighs 250 g. If you couple it to an 8-mm-diameter output shaft, the shaft's surface speed is 8.4 m/s or 30 km/hour. Hook up a 10 cfm cooling fan to remove the 250 watts of heat (the other 25%), mount…

> The "2CV" in the car name was kind of a tax fraud, though. It was not, the taxable horsepower and the “actual” horsepower are completely different things, as the former is derived from displacement (and / or gear speed at a fixed rpm). There was no fraud because this was how it was expected to work.

From my point of view, making the taxable horsepower a completely different thing from the actual horsepower is a fraud. Maybe you mean that the fraud was perpetrated by the tax office and not Citroen?

Re: Citroen 2cv pages

#79

Post by Doxin »

RalfWausE wrote: post #73
sbarre wrote: post #58

Earlier quoted context omitted.

Wonder if they could make an electric version of the wagon? It could be great as a short-haul utility/delivery vehicle...

Now... my parents have this for driving around town: https://elektrofrosch-berlin.de I think its a good successor of the spirit of the 2cv

Oh man that thing is amazing! I would LOVE if a bunch of goods transport could be substituted with those. I'd not be opposed to driving one myself.

Re: Citroen 2cv pages

#80

Post by surmoi »

When I was at school, we studied the specifications document for that car which are really interesting! The car was designed to transport two farmers with "sabots" (wooden shoes) and either 50Kg of potatoes or a keg. The whole history of the car is of note, I encourage you to look into it if you are curious! (cf. http://www.la2cvmania.be/09_TPV_1939_2cv.htm)

For a bit of context, design started in 1935, a third of the french population was still working in farms, although it was declining. I wonder if they thought it could not go much lower than that. (cf. https://fr.wikipedia.org/wiki/Loi_des_trois_secteurs#/media/...)

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