F4U-5 Corsair engine (R-2800-32W) - calibration test

[Galahad]

Hi @all,
I don't know if this maybe has been topic before - but found this very interesting file (caution, 77 MB !):

Defense Technical Information Center

apps.dtic.mil

The R-2800-32W is also known to have water injection, but from what I understand it's strangely not mentioned anywhere in the entire document.

They made take-off, normal and military ratings and so-called "overpower runs" up to 72,5 inch HG.
Is it possible to achieve on a R-2800 such high boosts without water injection?
Or in other words: if not, why they don't mention it that water injection was used?

btw:
I think in Korean War -5 Corsairs surely had seen combat power ratings (and surely with water…)

 

[MiTasol]

Interesting report - especially the multiple spark plug failures and compressor stall.

As you say - no mention of water meth but maybe because it operated trouble free.

 

[Metrallaroja]

The Aeronautical Engine Laboratory Calibration Reports dont include water injection runs.
Water Injection testing is usually up to the military flight reports.

If you want to know F4U-5 water injection performance:

National Archives NextGen Catalog

The online portal to the records held at the National Archives, and information about those records.

catalog.archives.gov

Power Plant Chart from flight manual:

 

[Galahad]

Thanks for the link, big datas... From what I understand special dynamometer runs are usually manufacturers job, not up the military flight reports.

Is it known why Calibration Reports don't include water injection test? "Operating Limit Charts" in many flight manuals only show MILITARY and not COMBAT power values, should pilots and crews not know that? Applies this only for Pratt & Whitney or other manufacturers too?

 

[Metrallaroja]

Thanks for the link, big datas... From what I understand special dynamometer runs are usually manufacturers job, not up the military flight reports.

Manufacturers did the developing of water injection but I guess it was up to the military to test the limits of it on aircrafts. That would be as a Laboratory Report or as a Flight Test Report, as needed.

Is it known why Calibration Reports don't include water injection test? "Operating Limit Charts" in many flight manuals only show MILITARY and not COMBAT power values, should pilots and crews not know that? Applies this only for Pratt & Whitney or other manufacturers too?

In all calibration reports I saw there is no water injection included.
Calibration reports are made by the Military, see ''Bureau of Aeronautics''

This are reports from the Aeronautical Engine Laboratory: AEL Report Indesx

It seems that when needed this Navy Laboratory did some water injection reports like for F8F and F7F engine:

This kind of reports are of only combat power.

But I guess other times water injection values would just be tested in flight testing facilities and sent in a more simple letter to the relevant organizations like this ones:

http://www.wwiiaircraftperformance.org/f4u/f4u-1-50030.pdf

http://www.wwiiaircraftperformance.org/f4u/f4u-1-17930.pdf

And like the report about F4U-5 I sent you.

Pilots should know water injection limits, but the Bureau of Aeronautics had to test and validate this limits before including them in the flight manual.
Maybe before that pilots got the information via a direct preliminary Bureau letter.
See how for example here it says ''To be furnished by navy department bureau of aeronautics''

 

[Metrallaroja]

Also worth to note that in that XF8B-1 power plant chart values are from Pratt and Whitney.
I guess meanwhile the Bureau of Aeronautics did not have a report letter ready or any flight tests some flight manuals used P&W data.
Because in many flight manuals you will see that the data used is based in AEL (Aeronautical Engine Laboratory)
like for example F6F, F8F, F7F or F2G flight manuals

 

[Galahad]

Thank you for detailed explanation, great!

 

[Metrallaroja]

Hi @all,
I don't know if this maybe has been topic before - but found this very interesting file (caution, 77 MB !):

Defense Technical Information Center

apps.dtic.mil

The R-2800-32W is also known to have water injection, but from what I understand it's strangely not mentioned anywhere in the entire document.

They made take-off, normal and military ratings and so-called "overpower runs" up to 72,5 inch HG.
Is it possible to achieve on a R-2800 such high boosts without water injection?
Or in other words: if not, why they don't mention it that water injection was used?

btw:
I think in Korean War -5 Corsairs surely had seen combat power ratings (and surely with water…)

https://www.aahs-online.org/images/Navy_SAC/F4U-5.pdf

I estimate clean performance would be about 25 knots faster.
So about 640kph at SL and 780kph at 31000 feet!