Converting to British Boost

[Paule]

I'm sure that somewhere I have seen a formula for going from Manifold Press (ins Hg) to Brit boost. Can anyone help me out as I need to try and estimate power figs for the Bristol Hercules 100 engine.

Ta much in anticipation.
Paul

[skeating]

Hi Paul,
I forget the actual formula but 29.92 Hg =14.7 psi I believe.
29.92hg is the pressure for an ICAO standard day at sea level (1013.2 millibars or Hectapascals as we now have to call them) which is equivilent to 14.7 psi.
I might be wrong but I am sure someone here will soon tell me if I am.

Steve

[emfrat]

Hi Paul -
Funnilynuff, that very same question was answered on CalClassic the other day:

British Boost pressure gauges read in PSI and can be converted by adding 14.7 for the standard atmosphere at sea level and multiplying by 2.04. The reverse of the equation works for the opposite conversion. (Divide MAP by 2.04 and subtract 14.7).

(Quoted from this post, reply No 5 in the thread: http://calclassic.proboards55.com/index ... thread=729 )

Always wanted to know meself - tried to suss it from a Pembroke panel which had both boost and map gauges, with no luck. :doho:

Cheers
MikeW

[Paule]

Thanks, Emfrat and Skeating. Course what would be extra nice is for someone to pop and say "Oh I've got full specs for Hercules 100". I should be so lucky.

Paul

[emfrat]

Cheers, Paul -
I had a look around the 'Net this morning. You have probably been everywhere I went already, but having found the 100 was used in the Short Seaford, which became the Solent, I had a look for Solent handling instructions and found this page:
http://www.forjets.netfirms.com/page8.html
At the bottom of the page are some interesting BHP/MAP/Boost graphs; they relate to the Solent3 with the 637 engines, but on the off-chance that you might be able to interpolate for the 100 engine, I thought I would post it.
Hope I am not wasting your time...

ATB
MikeW

[Paule]

Thanks MikeW, just off to try and save or print out the pages

cheers Paul

[DaveB]

Hmm.. the 637 was a more powerful engine than the 100 albeit not by much. Hope you find something out of there Paul but don't take too much notice of the performance/range figures off that summary as the Solent 3 was some 10600lbs heavier than the Halifax Mk8

ATB

DaveB :tab:

[Paule]

Dave, you bad person, twas meant to a secret.
Paul

[DaveB]

OOps! You never told me that!

ATB

DaveB :tab:

[Fodda]

I hadn't realised that the weight of a Solent 3 was still a state secret!

;-) ;-)