Design compromises ( historical)
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Design compromises ( historical)
A question for you proper engineers out there.
It has always bugged me that the german aircraft designers of ww2 persisted with the inertia start system.
Surely the weight of the rotating mass flywheel, and clutch is all heavier than an electric starter, battery and cables?
Youtube has a good clip of a tiger tank being started this way, but it makes more sense in a 27 tonne tank than an Me 109
Anybody know what the advantage was?
It has always bugged me that the german aircraft designers of ww2 persisted with the inertia start system.
Surely the weight of the rotating mass flywheel, and clutch is all heavier than an electric starter, battery and cables?
Youtube has a good clip of a tiger tank being started this way, but it makes more sense in a 27 tonne tank than an Me 109
Anybody know what the advantage was?
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My totally unsupported by any researched facts guess is that it may have had to do with available resources.
Could be the Germans had a critical shortage of copper or other material needed for electric starter system and since the other method worked they stuck with it
Could be the Germans had a critical shortage of copper or other material needed for electric starter system and since the other method worked they stuck with it
Even the ever-so-modern mighty Chinook helicopter has to be started by first hand-pumping 3000psi of Hyd power into a little accumulator...to start the APU.
This is deemed to be the perfect answer to a lack of battery power when waking up on a cold and frosty morning in the middle of a field. Something even the Luftwaffe did in WW2.
So the answer to your question is almost as MWR says - except it was probably more to do with the likelihood of flat batteries, and the need to start engines in a big field in the middle of no-where without electrics, rather than a lack of copper.
And even if this is wrong, it's still a good argument for the Flywheel.
This is deemed to be the perfect answer to a lack of battery power when waking up on a cold and frosty morning in the middle of a field. Something even the Luftwaffe did in WW2.
So the answer to your question is almost as MWR says - except it was probably more to do with the likelihood of flat batteries, and the need to start engines in a big field in the middle of no-where without electrics, rather than a lack of copper.
And even if this is wrong, it's still a good argument for the Flywheel.
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Or to put it another way, one of the design requirements for the 109 was ability to operate from forward airfields without much support.
A manual starting system would avoid a need to have a "trolley Acc" handy, to say nothing of a source for charging its batteries.
I'm not an expert, but I believe that early models of the Spitfire had a manual start system, although I have no idea of how it operated. But later ones presumably did not, perhaps because the engines just got too powerful to be started except with a battery cart providing a very high impact current to a starter.
I don't think that WWII fighters carried batteries for starting, as opposed to running electrical equipment after starting the engine, at least not the earlier ones from Europe, but I could be totally wrong about that; no doubt someone who knows will put me right.
A manual starting system would avoid a need to have a "trolley Acc" handy, to say nothing of a source for charging its batteries.
I'm not an expert, but I believe that early models of the Spitfire had a manual start system, although I have no idea of how it operated. But later ones presumably did not, perhaps because the engines just got too powerful to be started except with a battery cart providing a very high impact current to a starter.
I don't think that WWII fighters carried batteries for starting, as opposed to running electrical equipment after starting the engine, at least not the earlier ones from Europe, but I could be totally wrong about that; no doubt someone who knows will put me right.
Last edited by Capot; 10th Oct 2012 at 09:03.
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Capot thanks
A pragmatic approach to unsupported field operations makes sense to me. No resource shortages in the early 1930s when designed.
regards
HnH
A pragmatic approach to unsupported field operations makes sense to me. No resource shortages in the early 1930s when designed.
regards
HnH
