Author Topic: why does 109G10 climb so bad?? (Read 3736 times)

Pongo · « **Reply #30 on:** April 20, 2002, 02:17:40 AM »

It was a real 109g2 rebuilt to airworthy condition..Db605 and all.
then the stupid twits wrecked it....

Buzzbait · « **Reply #31 on:** April 20, 2002, 02:59:15 AM »

S! Funked

Are you gonna fly the CT when I run my late war setup with Spit XIV's perked at 2 points?

funkedup · « **Reply #32 on:** April 20, 2002, 04:16:25 AM »

Buzz I will whine about the perk price and fly in the MA in protest.

j/k

niklas · « **Reply #33 on:** April 20, 2002, 05:32:01 AM »

Quote

Originally posted by Nashwan

Could you explain what you mean?

Is it so hard to see? Just follow the link from funked and look at the charts from the links at the bottom. Compare them to the AH chart.
Why has an engine much less power in the High gear of the supercharger? Because it needs more power for more RPM. If you reduce the critical altitude you let the charger run with less RPM, and in case of the AFDU spit14 it means the spit was running with more power. Oh i just compared the speeds, the spit14 has the same speed like in the AFDU trials but a critical altitude for the 1st gear that is 5-7000ft higher - VERY FUNNY!
I modified those charts to demonstrate you the effect of the supercharger design. The blue line connects both critical altitudes. Now i draw a horizontal line from the AH critical altitudes, this gives me now the power with the new critical altitude. In case of the climbrate i can go down vertically (green line) or in case of the speed i draw a parallel line to the given curve.

Is my method 100% accurate? No, but very close. Is it better or worse for the spit? Actually better, because at low altitudes density changes much faster than in high altitudes. That means lowering your critical altitude from 5000 down to 2000 will give you more power than from 25000ft down to 22000ft.

You may also read the intro of the spitfire testing page, this gives you also some hints about the credibillity of the test

It is tycial for RAF tests of german equipment that in the case of the 109G - Spit comparison they doesn´t mention wing gondolas. In case of the 109E test they don´t mention engine or supercharger problems and so on. Always telling half the truth, what gives you of course a completly different view.

Anyway, the question is only to 30% why does the RAF planes climb so good, the question is to 70% why does the G10 climb so bad. Even G2 and G6 do ~4000ft/min, and the G10 is not much heavier but has a LOT more power. I always wondered myself but now the time has come to ask.

niklas

Daff · « **Reply #34 on:** April 20, 2002, 10:05:18 AM »

"then the stupid twits wrecked it...."

Yeah and that stupid twit was Mark Hannah, who died in hospital later and him and his father has been one of the best promoters and restorers of WW2 aircraft...what a bunch of twits.

Daff

Yeager · « **Reply #35 on:** April 20, 2002, 10:20:53 AM »

Ouch baby.....ouch

Vermillion · « **Reply #36 on:** April 20, 2002, 10:23:11 AM »

Ok back to the original subject.

Niklas your only looking at Horsepower to weight ratio. Like some other have said, don't forget drag as well.

But your forgetting once very important item.

Prop Efficency.

A good example is the F4U. The F4U-1(A) and the F4U-1D have essentially the same engine, and are close in many other physical characteristics, but the -1D climbs much better.

You have to transfer the power from the engine into acceleration, which is essentially the same as climb rate (ie excess power).

Naudet · « **Reply #37 on:** April 20, 2002, 11:04:22 AM »

The Spit XIV is that good. And the G10 is not a K4 which would reach 16K in about 3 minutes.

And the biggest changes between G10 and K4 - if i remember right - were small changes to make the K4 "cleaner" which is just reducing drag.

What we all should not forget is that roughly no operational planes in WW2 would match the numbers we have in AH.

There is an RAE report at the PRO (document # AVIA06-10393) that contains an examination on speed differences between data sheets (taken from the manufactures "production" machines) and real production plane performances on spitfires.

Production machines were slower in general even up to more than 25 mph. And this differt from machine to machine also.

So we in AH can atleast be glad that the planes we have perform like the performance charts on the AH page.

niklas · « **Reply #38 on:** April 20, 2002, 11:45:09 AM »

vermillion:
A) in a climb drag is not as much the deciding factor as for topspeed. After all the Spit was not better, maybe even worse looking at drag. More surface area, worse cooler and so on.

B) More blades doesn´t necessarily increase your efficiency. In opposite, in a slower flight - climb - the disturbing effects of one blade on the other is maybe even more pronounced than in a fast one. The Diameter wasn´t larger too.
Oh, when someone thinks the 3-bladed prop of the 109 couldn´t handle 2000hp: The world record machine 209 (109R) had an engine with 2770PS and a 3 bladed propeller with ~3m diameter.....

niklas

Wmaker · « **Reply #39 on:** April 20, 2002, 11:46:29 AM »

Quote

Originally posted by Daff
"then the stupid twits wrecked it...."

Yeah and that stupid twit was Mark Hannah, who died in hospital later and him and his father has been one of the best promoters and restorers of WW2 aircraft...what a bunch of twits.

Nope Daff, The accident that Mark Hanna died in involved OFMC's Hispano Buchon HA-1112-M1L G-BOML. NOT Black 6 which is an original Bf-109G-2.

Black 6 was wrecked by RAF officer, and yes, he was a twit.

Nashwan · « **Reply #40 on:** April 20, 2002, 12:16:58 PM »

Niklas, at the start of the Spitfire page Funked linked to, they mention production aircraft would get a different ms supercharger gear ratio. That would explain the differences, and the fact that the AH Spit climbs worse at low level than the tested one.

I found these charts over at the All About Warfare forum, courtesy of Neil Sterling.

http://pub47.ezboard.com/fallboutwarfarefrm1.showMessage?topicID=777.topic

Perhaps the RAF made them up, too?

ra · « **Reply #41 on:** April 20, 2002, 01:48:43 PM »

I wanna Hornet.

SageFIN · « **Reply #42 on:** April 20, 2002, 02:05:10 PM »

Hmm, I wonder where Ho Hun and Wells are. More viewpoints from the aeronautical angle would come in handy in this debate.

niklas · « **Reply #43 on:** April 20, 2002, 02:54:17 PM »

Quote

Originally posted by Nashwan
Niklas, at the start of the Spitfire page Funked linked to, they mention production aircraft would get a different ms supercharger gear ratio. That would explain the differences, and the fact that the AH Spit climbs worse at low level than the tested one.

You don´t want to understand or what? The AH sptifire climbs too good, not too bad. Just look at the green lines in the charts.

Any further details avaiable for the charts of butch2k´s page? Aircraft description, weapon load, surface condition, speedcorrection and so on?

nik

Viper17 · « **Reply #44 on:** April 20, 2002, 04:11:08 PM »

ALL WILL KILL SPITFIRES:D