Hop you really should learn to read those charts...
The figures on that chart are at Start u. Notleistung, and "Without" MW-50, as-well as at a considerable overweight. Oh and they are at 1.8 ata supercharger pressure. (Notice "Grundeinstellg", and how the top figure at 1.8ata is the best climbing one)
I know. Note that I said the climb rate of the K4 with Mw50 and C3 fuel was close to 25 m/s, this chart shows a maximum close to 22 m/s.
The most interesting thing about this chart is that it's almost certainly the source for the mistaken "3 mins to 3,000m" and "6.7 mins to 10,000m" claims.
Oh, and where did William Green misread that chart ? It says exactly 6.7min to 10k
No it doesn't. You are assuming the m/s scale is also minutes. I assume Green made the same assumption. Most of the people who see this chart do.
The M/S scale is not also minutes. In fact, 1 square on that chart = 2 minutes, so the 5 m/s line is also the 10 minute line. The chart shows time to climb at climb and combat power, 1.45 ata, basic setting 1.98 ata (ie an engine configured to run at up to 1.98 ata, but actually running at 1.45 ata)
I worked this out some time ago, because the times on the time to climb line correspond to the times to climb at 1.45ata, and couldn't possibly correspond to 1 square = 1 minute. However, I've since seen the other charts, including the 1.98 ata one I mentioned earlier, and they actually have a visible minute scale along the bottom. 1 square = 2 minutes.
Look at at the time to climb from 2km to 4km on this chart.
If 1 square = 1 minute, it takes just over 1 minute to climb 2km, a rate of 28.5 m/s. That's very fast at that altitude.
If 1 square = 2 minutes, it takes about 2.3 minutes to climb 2km. That's a rate of about 14 m/s. If you look at the climb chart at 3km (the average height between 2 and 4km) then the climb rate is 14 m/s.
You can do this at any height. Try for example 1km to 5km. It's a straight line on the climb chart, so the average speed will be half way along, at 3km. The climb rate at 3km is 14 m/s. To climb from 1km to 4km should take 285 secs at an average of 14 m/s. That's 4.75 mintues.
Look at the time to climb line. If 1 square = 2 minutes, 1km is reached at a shade over 1 minute, 5 km at just under 6 minutes. In other words, it takes about 4.75 minutes to go from 1km to 5km, if 1 square = 2 mins on that chart.
Whilst this works at any altitude, it's most obvious above 8km. Above 8km, the 109 cannot maintain maximum boost pressure, so increasing allowed boost pressure will make no difference. RPM is already at maximum because max rpm was allowed as a climbing setting above 8000m (see the line joining climb and combat and start and emergency at 8,000m)
If 1 square = 1 min, then it takes about 1.7 minutes to climb from 8 to 10 km. That's an average, at 9km, of over 19 m/s. Try plotting that on the chart, at 9 km. It's so far off the actual climb rate it's clearly nonsense. And remember, increasing allowed manifold pressure will do nothing at this altitude, because the supercharger can't even maintain 1.45 ata, let alone 1.8 or 1.98 ata.
Now, if 1 square = 2 minutes, then it takes about 3.3 minutes to climb from 8km to 10km. That's a rate of about 10m/s at 9km, which is bang on the chart.
Whatever altitude you want to plot, you will see that at 1 square = 2 minutes, the time to climb matches climb and combat power.
Btw, please show us that 1.98ata chart of yours, then I'll tell you what it says, thank you.
It's quite clear what it says. It still only shows climb rate at climb and combat, and gives about 13.5 minutes to 10,000m. But there's no calculation needed to prove it, the extra scale for minutes is clear at the bottom.
I'd rather not post it here, because the chap who paid for it from the archives, and who first posted it on Ubi, has since removed the link. However, as he posted it on a public forum, which anyone can join and read, I have no objection in emailing it to you, if you provide an address. (if you'd rather not give out a real address, create a temporary Hotmail or similar account).
