ATAG_Snapper
May-04-2012, 17:10
Here's some interesting data I gathered today flying the Spifire Mark Ia and IIa from Cliffs of Dover and Air-2-Air (A2A) Simulations Wings of Power 3 Spitfire. Just a quick test comparing the following:The two sims' Spitfire Ia and IIaA2A's 100 octane vs 87 octanePerformance (Airspeed Indicated -- AIS) at 0 feet, 5,000 feet, and 10,000 feet.Two boost settings: 2.5 lbs and Full OverboostTwo rpm settings: 2800 rpms and 3000 rpmsThe methodology was pretty basic. Full gas tank and ammo load, take off from coastal airfield, fly to given altitude, close radiator halfway, adjust engine settings (prop pitch -- rpms, throttle -- boost), then trim for level flight at the designated altitude and note airspeed indicated (AIS) after a minute or two once the speed remained constant.Quite an eye-opener. I'll have to convert the 5,000 and 10,000 AIS data to True Air Speed (TAS). One note: CoD Spits do NOT like 2800 rpms as indicated by engine/airframe vibration. I actually blew the IIa Merlin at 3,000 rpms at 10,000 feet.Fuel Mixture was left at Auto Rich in both aircraft for all trials.NOTE: This is not a definitive test by any stretch of the imagination, this is why I've just posted this to the ATAG Forum. Conclusion: the CoD IIa more closely matches the A2A's Ia and IIa performance; the CoD Spitfire Ia just sucks dust -- no surprise there. :bgsmile:Interestingly, the A2A Spitfire Ia does NOT have a Constant Speed Prop, although the C0D Spit Ia does. The A2A Spit Ia has a 2-speed prop, but it's one step more authentic than the CoD's Spitfire Mark I 2-speed prop.....you can change pitch manually between Coarse and Fine. The real BoB pilots quickly discovered that if you carefully move the 2-speed prop pitch control (which looks like a bicycle pump handle, it's not a lever at all!!) in between the two extreme pitch settings, you can actually get intermediate pitch settings on the propellor. This was major in extracting optimum power from the engine. However, because it wasn't a Constant Speed Prop, they had to keep an eye on it at all times because the rpms would go up and down depending on boost level, and even when you changed direction or altitude. Like all good pilots, they got really good at judging the prop pitch/engine rpms by ear, so they didn't have to keep staring at their tachometer all the time. (It's like a Harley Davidson with a tachometer.....clearly its frickin' exhaust pipes aren't LOUD ENOUGH!!!! LOL)In my haste to get this out to everyone here, I haven't even looked over the data to analyze it yet -- I just double checked it for no typos. Laugh, weep, or throw bottles -- knock yerselves out! :runaway::hiding:EDIT: I'll do this again post patch. I didn't do the 18,000 feet altitude trials due to time constraints, plus I admit it does stick in my craw. ALL of my dogfights against 109's have been at 10,000 feet or less -- usually MUCH less. Even when jumped by high-flying 109's as I'm engaging enemy bombers at 12K - 14.5K, the ensuing fight will occur at lower altitude because the Ia ain't much of a climber vs a 109.