Since David was unable, or unwilling to provide the real 'data' his claim is based on, I figured I would give it a quick look.
To see what all the fuss is about, ie are we talking about
10?
20?
30?
40?
In doing so I found some 109G data but not E data, here is the sorce
http://www.wwiiaircraftperformance.o...9/14026pg9.jpg
Now it is really hard to read the speed axis, but it 'looks' like it goes
520
530
540
550
560
If that is the case, than the 'difference' in speed between open and closed is..
5 kph
Which is well within the pilot error noise
Thus, IMHO, the only way to detect this small change is to log the data and account for the pilot errors
PS correct me if I am wrong, but the rads on the 109 changed alot from the E to the G, so, assuming Jerry did a better job on the new rads, we can only assume that the older E rads caused more drag, and thus impacted speed more. But, even if the change was doulbe this, say 10kph, it is still well within the pilot error noise