HERCULES Mk.XI

PETE:

Many thanks.

With kind regards – Malcolm.

Does anyone know where this plate would have been fixed in an aircraft?

With kind regards – Malcolm.[/QUOTE]

In the cockpit

Pete

CREAKING DOOR:

Many thanks for the informed reply. I am particulary surprised by the number of aircraft using this engine as I had originally thought it to have seen only limited use!

Does anyone know where this plate would have been fixed in an aircraft?

With kind regards – Malcolm.

I presume that the information that the plate contains should identify what aircraft these engines were fitted to.

I’m not sure you’ll ever discover what type of aircraft these data plates were from; there just doesn’t seem to be enough unique information on either one.

As you probably know the Hercules XI was a two-speed single-stage supercharged radial.

The ‘M’ and ‘S’ in the first column of data refers to the speed of the supercharger (which was gear driven) with ‘M’ being the low-gear and ‘S’ being the high-gear.

The supercharger speeds (gear-ratios) for the similar Hercules VI were 6.68:1 for ‘M’ gear and 8.36:1 for ‘S’ gear.

The other columns are self explanatory, RPM, Boost Pressure, Cylinder Head Temperature and Oil Temperature.

The difference in data between the two plates is basically that one engine is rated to run at higher cruising RPM with higher boost pressure and that engine therefore produces more power (but has higher cylinder head and oil temperatures).

The easiest way to explain this is that this is essentially an identical engine running on petrol with a higher octane rating.

How many of each type used these engines would be an interesting point.

As for the numbers of aircraft using the Hercules XI:

Stirling I (series II) – 117
Stirling I (series III) – 307
Albemarle I –
Albemarle II – 100
Albemarle V – 50
Albemarle VI – 250
Beaufighter I – 120
Wellington III – 1517

Just these quick totals above require 5770 engines…and I know I’ve missed some.

Hello Pete:

Thanks for taking the time to reply. I did not realise that these engines were also fitted to the Stirling which I find really interesting. Good point regarding the information recorded on each plate possibly indicating a different aircraft type. Hopefully this will help with identification.

Anyone have any ideas on how I could place a larger picture up?

With kind regards – Malcolm.

Malcolm.

The Hercules XI was also fitted to:
Albermarle I,II,V and VI
Stirling I series II and III
Wellington III and X

Incidentally, the Beaufighter IIF was fitted with Merlin XXs, there`s no such engine as a Merlin XI !

I wonder if the different rating plates apply to fighter / bomber installations?

Pete

NEWFOREST:

Thank you for the link. It is very helpful. I presume that the information that the plate contains should identify what aircraft these engines were fitted to. I not that it was also used on the Wellington III and Albermarle. How many of each type used these engines would be an interesting point.

With kind regards – Malcolm.

Addt. info.

As you say, could be Mk.1 Beaufighter.

Bristol Beaufighter
Model Engine(s) Crew Other
Mk IC 2 Bristol Hercules XI 2

Mk IF 2 Bristol Hercules XI 2

Mk IIF 2 Rolls-Royce Merlin XI 2

Mk V 2 2

Mk VI 2 Bristol Hercules VI/XVI 2

Mk VIC 2 Bristol Hercules VI/XVI 2

Mk VIF 2 Bristol Hercules VI/XVI 2

Mk VI (ITF) 2 Bristol Hercules XVI 2

TF Mk X 2 Bristol Hercules XVII 2

TT Mk 10 2 Bristol Hercules XVII 2

Mk XIC 2 Bristol Hercules XI 2

Mk 21 2 Bristol Hercules XVII

Good history of the Hercules here:

http://www.answers.com/topic/bristol-hercules

Any ideas?

With kind regards – Malcolm.