Quote:
Originally Posted by camber
After reading through this thread and the last big thread on this issue:
http://forum.1cpublishing.eu/showthread.php?t=32259
I am still in the camp of the typical 109E doing around 475kmh at SL and 560kmh TAS top speed. IMO it is too much argument work to make the available flight tests match the 500kmh deck speed for series 109Es, as opposed to allowing that the aircraft were actually around the pass/fail level at SL (but OK at alt).
One thing that was brought up in the last thread, that the aircraft would be "failed" and sent back to Messerschmitt if they did <475kmh at SL. However, the 109G acceptance plot posted in this thread shows testing at a single altitude that varies but is closer to FTH than SL. It makes sense to me that acceptance tests would not be based on a full speed vs alt test regime, and especially not an actual test of the 109 belting along at sea level (a bit difficult to arrange except in CloD). So a 109 doing 470kmh at SL could still pass.
The other thing is considering 1.3ata vs 1.35ata. If the actual limit was 5 mins 1.3ata without the takeoff boost, I don't see that the fact the CloD 109s show 1.35ata suggests they should be made faster than historical (although we are getting toward hair splitting). Instead the CloD boost indication should be fixed or ignored. In the same way if the CloD Spit boost gauge showed +14psi, I wouldn't expect it to be made faster than historical to match the gauge.
One thing I really find interesting for 109s is combat use of the 1 minute takeoff boost. Whether or not it actually works except close to SL really depends on how it is designed...similarly to difference between the actual Spit II gated takeoff boost (will decay quickly with alt) and red tab combat boost (will work at any alt the supercharger is capable of delivering it).
Right now the 1.45ata works even up to FTH (odd), which seems very unlikely. But in real life it should certainly work if you are chasing or being chased low over the channel, but I have not seen a combat report or memoir that confirms this.
With that all said, I would be happy with 500kmh SL 109s if that gave the best and most fulfilling online CloD for both red and blue (with red FM fixed too)
camber |
Did not read your excellent compilation in post#1 until now but I think it does a good job of summing up the situation so thanks for the info!
Some additional thoughts on the Me109E speed issue: First of all that 1.35 and not 1.3 ata was displayed in the CloD was news and also that take-off boost as high as 1.45 ata was usable at altitude. Wonder why they modelled it like that? Is there some data indicating that this was the case? Most data I have seen list Dauerleistung 1.15 ata, Steig und Kampffleistung 1.23 ata and then the 1.3 and 1.4 ata Startleistung boosts. Anyway, it just struck me that there is an alternative way of accessing Me109E sea level speed at 1.3 ata boost:
If one assumes that the Steig und Kampffleistung figure of 460 Km/h according to datenblatt L. Dv 556/3 at 1.23 ata boost is correct then one can use this to estimate the ballpark figure for 1.3 ata. Assuming that the prop efficiency is about the same and that the drag coefficients are fairly constant ( I think this is reasonable given that the induced drag is not a major factor at top speed and that if anything, the Cdo should go up somewhat due to compressibility effects) one could calculate this:
Assuming 910 Ps at 1.23 ata and 990 Ps at 1.3 ata (From datenblatt L.Dv 556/3)
Solving for speed at 1.3 ata:
v=460 x (990/910)^(1/3)= 473 Km/h
So if we assume that the speed figure of 460 Km/h at Steig und Kampffleistung is correct then this would lend further credence to the 475 Km/h figure at 1.3 ata.
Interestingly, using the same principle for the Spitfire Mk1 at +6.25 and +12 boost is spot on compared to the chart figure of 314 mph at +12 boost:
Assuming 885 hp and a top speed of 283 mph at +6.25 boost this then gives for +12 boost assuming 1201 hp:
v=283 x (1201/885)^(1/3)= 313 mph