AH Jugs, a couple questions

[eddiek]

Hop in the D30 Daff, we only get 64 or 65" of MAP in WEP, not 68".....how much difference would that make?

[Daff]

I *was* quoting from memory, so I might be wrong. Is it 58" in the -25 and 64" in the -30?.
In any case, the -30 should have a lot more omphhh than the two others.

Daff

[Vector]

Ver 1.08 D-30 wep boost didn't affect to speed much, only 3 mph, has anyone tested the climb?

[Regurge]

The D30 gained about 2-300fpm in wep climb for 1.08. At least at low alt, all the AH Jugs climb as indicated in the charts.

One thing I can't figure out, the D25 feels (to me) more manueverable and has less E-bleed than the D30. Yet it has less wep power and weighs the same 14,500lbs as the D30 shown in the help files. Maybe the D25 weight is a typo? The dive flaps and dorsal fillet had to weigh something right? Of course I could just be imagining things, since I've done some objective testing and the D25 never comes out ahead.

[Vortex]

Right Daff. I beleive there was an increase in the power generated though with the D-27. My source states the following..."An extra 130 horsepower was added to the D-27-RE when water injection was added to the engine." ("P-47 in action"). I think the wording on that is kind of poor as earlier it does indeed note the fact that the D-5 was the first to accomodate water injection at all. Accordingly I read it as an increase to the boost with the -27.  That would explain the wep performance difference (and identical non-wep performance) between the -25 and -30 that we see on the data charts used to build the AH planes.  Do you have any info that confirms that...or perhaps explains it better?

Vortex

[gripen]

AFAIK highest authorized rating for the B series R-2800 was 64". But all claims I have seen about use of this rating are  from pacific. In the ETO standard rating with ADI  was first 56"  and then it was raised to 58".  Late D models (D-25?), were rated for 62".

gripen

[Vector]

As R-2800 durability was its own class it could be that over boosting engines was common? There is interesting writting of over boosting R-2800-C engine to find its limits:

During durability testing of the C series R-2800 by Republic, it was decided to find out at what manifold pressure and carburetor temperature detonation could be induced. They ran the engine at extreme boost pressures that produced 3,600 hp! But wait, it gets even more amazing. They ran it at 3,600 hp for 250 hours, without any failure! This, with common 100/130 avgas. No special fuels were used. Granted, the engines were completely worn out, but survived without a single component failure.

(Extract fromThe Republic P-47M, the fastest piston engine fighter of the war. )

And another interesting extract:
Just prior to World War II, Frank Walker was responsible for the development of anti-detonation injection (ADI) for the R-2800. ADI forces a water-alcohol mix into the induction system to cool the supercharged fuel-air mixture, thereby allowing a much higher manifold pressures and power outputs. Using ADI, Walker was able to coax 3800 HP from an experimental “C” engine at manifold pressures up to 150 in Hg!

From site: Aircraft Engine Historical Society  ("Conclusion.pdf").

[gripen]

Well, actually Walker did 3800hp on a  B-series engine (according to White). But this was under test  enviroment (special cooling and so on) and max possible ADI. Generally limiting factor for the B-series R-2800 was overheating.
 
gripen