"M" series Merlins

[Engineman]

I confirm. My copy is the fourth edition, 1995, "reprinted with minor adjustments in 2003". ISBN 1 872922 06 6.

Yes, 2750 isn't much different from 3000, but that's almost a 10% difference. I think Lumsden mixed up the rev numbers, and altitude.

Thanks,
Mine '87, maybe I should get the updated one!
Cheers

Eng

 

[Simon Thomas]

2750 vs 3000 ft is a ~10% difference in height, but it results in a less than 1% difference in density ratio.
Interesting that Lumsden states that the 45M has a maximum power of 1,580 hp at 2,600 ft on p210 cf 1,585 hp @ 3000 ft in Part 4.
I noticed that the RR book has the wrong impeller diameter for the Merlin 55MA on p.157 but correct on p. 148.

 

[Bretoal2]

2750 vs 3000 ft is a ~10% difference in height, but it results in a less than 1% difference in density ratio.
Interesting that Lumsden states that the 45M has a maximum power of 1,580 hp at 2,600 ft on p210 cf 1,585 hp @ 3000 ft in Part 4.
I noticed that the RR book has the wrong impeller diameter for the Merlin 55MA on p.157 but correct on p. 148.

Yes but on p.157, far right, is stated "55MA = exactly as 45M, but 2-pieces blocks" - and the 45M is said "cropped supercharger rotor". Obviously the value 10.25" is a typo error.