109 e3b against spitfire II

[Viper2000]

Originally Posted by Crumpp

The Allies did not have any direct injection engine technology to use.....

They could not make direct injection workable or practical using their fuel metering technology. Bosch's design, up until recently was the pinnacle of direct injection technology. It requires very high fuel pressures and the German system used a high pressure pump for each cylinder.

As already pointed out, post war, the turbine was supreme so why would any nation waste resources for a post war piston engine aircraft?????

Post WWII, it was perfectly within the Allies' rights to confiscate any and all German IP that they were interested in. So they could have made Bosch fuel injectors and put them into their engines at no great cost. They chose not to.

As for post-war engine development, the US government funded considerable development work on the R-3350 turbocompound, and indeed also upon the R-4360, both of which found their way into airline service.

Britain funded development of the Napier Nomad, which was a more ambitious take on the turbocompound idea (I strongly suspect that this engine was cancelled due to failure to meet its quoted performance; I modelled it in considerable detail a couple of years ago, and I could never make the quoted component efficiencies add up to the quoted SFC...).

Direct injection makes a lot of sense for naturally aspirated engines, compression ignition engines, or engines which operate over a wide power range. It's less attractive for a big aero-engine because if you're operating at fixed power with a reasonable amount of supercharge you should be able to attain excellent mixture distribution, and so the pragmatic solution is to have single point injection into the eye of the supercharger - which is basically what everybody ended up doing.

Of course, these days people aren't designing big piston aero-engines anymore, and they aren't supercharging*, so DI makes sense.

*and turbochargers tend to be bought from turbocharger companies, which means that injection into the eye of the turbo-supercharger impeller isn't really an option because it would be too much of a nightmare to organise the development effort - who pays for what etc?

[TomcatViP]

Originally Posted by Viper2000

... so the pragmatic solution is to have single point injection into the eye of the supercharger ...

I like that ... Good point.

However this shld lead to a certain amount of "latency" with DI eng being more reactive upon power changes by the pilot

Regarding the Merlin as an airliner eng, it has proved unreliable as high power value were run only at high boost and then prove to be non-efficient (the cruise power has always been low); Add to the disastrous engineering of Britain's airliner projects tht seems to hve been hand-ended by gvrnmt officials (don't take me wrong France had to face the very same situation until legitimate firms could emerge out of the bundle in earlies 60's) and you'll end with a more pragmatic vision of the failure of the British industry in perspective of the US success stories like Boeing/Doug/Lockheed right after war end.

Humm hve we run OT (out of topic) again?