See pressure charts here: http://www.flightglobal.com/pdfarchive/ ... 01223.html
The aforementioned Napier Nomad was operating on a "...nominal comp-ratio of 49/1".
(On a 2T static/geometric ratio of 8:1)
Actually T-C, if you take the trouble to read the 'Flight' article..Tommy Cookers wrote: ↑08 Jun 2018, 12:43the Nomad showed that CI with CR as low as a compounded SI engine's could use cheap fuel - but it was not more efficient
ie the Nomad 1 had the same 'best bte' as the Wright Turbo Compound (and the Nomad 2's was worse ?)
but diesel fuel seems to be not intrinsically cheap
normal piston engines are anyway compounded in flight at reasonable altitude and speed by inherent exhaust jet effect
Napier (and Wright) clearly claim merit only in relatively slow flight
the only significant CI (mechanically) compounded engine was/is a USSR 42 and 56 cylinder marine job - eg 5200 hp/unit
yes these to a greater or lesser extent benefit from heat dilution as does F1
the Nomad of course had multi-stage compressors and axial turbines - F1 limits itself to single stage
btw
airliners operate in cruise with their altimeters set to 1013 millibar regardless of actual surface or sea level pressure
so eg Flight Level 360 means fictitious 36000' reading not 36000' actual
and the plane coming the other way will be flying at a similarly fictitious 37000' reading - so is seperated by an actual 1000'
I suppose if you tried maximum fuel flow at too low an engine speed, you would end up with this:
It would be interesting to know what RPM range these engines would run at if they dropped the 10.5k RPM threshold for the maximum fuel flow rate. Minimum engine speeds would be limited by cylinder pressures, but advantaged by reduced piston speed & acceleration. Would development trend toward heavier, slower running components with high cylinder pressures? Or toward lighter, faster running components with lower cylinder pressures?gruntguru wrote: ↑08 Jun 2018, 02:37https://www.youtube.com/watch?v=kqVwHJPV-XE
See dyno runs at 3:00.
Yes
Mass air flow is what you are trying to read to calculate the amount of fuel required for combustion.
A "hot wire" MAF directly measures air mass flow - exactly what you need to know when you want to flow fuel into the engine at a chosen AFR.