Quote:
Originally Posted by Seadog
Fighters, by definition cannot run for more than about 40 - 50 minutes at 12lb boost/3000rpm because of fuel limitations, and yet if a fighter could only be flown for a few moments at 12lb/3000rpm then there would be no need to point out the increased fuel consumption at 12lb/3000rpm (see point 4 in AP1590G above at 12:27PM)
Cooling on the ground and cooling in the air are two separate issues. This is a test of a Spit V at the normal and combat ratings, and the plane was flown repeatedly to its service ceiling at 16lb boost:
http://www.spitfireperformance.com/aa878.html
and the aircraft was specifically tested for cooling suitability at 16lb boost and was found acceptable for English summer conditions and this required considerably more cooling than at 12lb. |
I am not saying the engines should suffer from major overheating issues if pushed for a few minutes but they should and did overheat if pushed to high for too long. The Spitfire Mk Vc had a larger radiator and had better cooling than a Mk I and Mk II, so while it is very relevant it is not a perfect example. I know these engines could take more punishment than just a few minutes at full power, but they weren't immune to breaking if pushed. Definately more punishement than a mere admin warning. I also know that cooling on the ground and cooling in flight behave differently, I am just pointing out the fact that CoD does not model overheating on the ground very well. I can sit indefinately with the radiator open on the ground at 1200 rpm, something that couldn't be done in real life in a Mk I Spitfire.
Quote:
Originally Posted by Seadog
I don't have any "agenda" other than historical accuracy. Every Hurricane and Spitfire in RAFFC could use 12lb boost, and there was no 'magic' limit after which the engine caught fire or blew up or seized up. Using 12lb boost simply increased the wear and tear on the engines and probably kept the ground crews up late at night doing engine checks but this probably caused little concern to pilots whose lives and/or aircraft were saved or who ensured kills by "pulling the plug" and going all out. It is quite telling that the Merlin III could be modded to accept 16lb boost on the Sea Hurricane I with essentially identical engines and cooling as per BofB Hurricanes.
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I know these planes ran at +12lb boost, I have no problem with that. My only issue is with the fact that you seem to be advocating they should run without problems at +12lbs boost until the fuel ran out. ALL of the scenarios you refer to would not require +12lbs boost for more than a few minutes. In reality it would be unlikey that someone would follow your full power dive for more than a few minutes. I know if I was in a Spitfire Mk Ia in 1940 I would not dive after a 109E in a full power dive for very long, especially considering that in a few short minutes I would most likely be flying over France at low altitude with an engine starting to run hot.
In the Mk Vc full power test you linked to the radiator temperature reached 124 C at 12.000ft after 3 minutes, OAT was +5 C. This is already 4 C higher than the recommended maximum, at 130 C the Merlin had to start venting to reduce coolant pressure (small hole on right side of engine cowling just behind the prop). If this test had been done at lower altitude in the hotter air then it would almost certainly have overheated without pilot intervention. It was easier to keep these planes cool at 12,000 or 24,000 ft than it was at SL.
Quote:
Originally Posted by Seadog
If COD is going to be an accurate simulation then it has to allow 12lb boost at the pilot's discretion, and then factor in some kind of admin penalty for using it without justification.
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See my response above. I do not want unrealistically hard overheating modelling for any of the aircraft. What I do want is the fact that sometimes if you push too hard for too long that there MAY be repurcussions that go beyond an admin reprimand. Apart form the ground cooling issues CoD seems to do quite well in this regard.