Originally Posted by BP_Tailspin (Post 356745)

This place never ceases to entertain me …

Originally Posted by BP_Tailspin (Post 356745)

Should they have an impact on speed?

Originally Posted by ACE-OF-ACES (Post 356755)

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

Originally Posted by David198502 (Post 356760)

well that document is really hard to read....however how do you come to the conclusion of 5kph differnce?

maybe i read it wrong....there are two different graphs which show the speed per rads setting.
however both show a straight decreasing line with the same angle...so the difference remains the same.
the lower line shows a speed of 555kph with 50mm opened rads, and only 505kph with 310mm opened rads(which is not fully open).

50kph difference between not fully closed and not fully opened rads...

Originally Posted by Robo. (Post 356759)

You just contributed quite a few jokes yourself :)



Of course.

You're right with a P-51, but completely wrong with a 109 (and Spitfire and Hurricane)

No offence dude ;)

Originally Posted by ACE-OF-ACES (Post 356766)

As noted, hard to read the graph, but assuming 'speed' is on the bottom (x axis) and that it goes as follows

520 - 530 - 540 - 550 - 560

Now looking at the point where the two curves intersect (y=0) the bottom (x axis) we have

1st @ ~523.5kph
2nd @ ~528.5kph

5 = 528.5 - 523.5

That is what I got, but again, I could be reading it wrong too.. That graph is hard to read

But..

Lets not use that graph.. Lets use the 109E data your claim was based on! That would be the correct thing to do! Now that I got your att on the subject! ;)

Originally Posted by 41Sqn_Stormcrow (Post 356774)

Mh. Have you guys ever managed to slightly close the radiator of the 109 at full throttle without getting immediate overheat? I really don't see how one can close the rads almost full at full throttle without overheating it in split seconds.

In any aircraft when you are at full performance settings (throttle + rpm) I never ever dare to close the rads a little bit because overheating is looming.

Originally Posted by David198502 (Post 356630)

i surprisingly just found out that the rads settings of the 109 have no impact on speed at all...
normally i fly with them as much closed as possible,to avoid engine overheating,while maintaining the minimum air resistance...
however i found out that one can leave the rads fully open and still reach and hold the top speed in level flight....

Originally Posted by David198502 (Post 356773)

the whole document is twisted 90° left.
so the speed is actually on the y axis.

Originally Posted by David198502 (Post 356773)

but there is also the temperature on the y axis as well in the lower half...

Originally Posted by David198502 (Post 356773)

and the rads settings are on the x axis in mm.

Originally Posted by David198502 (Post 356773)

so the doc you provided states a difference of more than 50kph between open and closed rads.