Recent content by hrandy

Most descriptions of the rushed production of the Spitfire 5 state that the two speed Merlins could not be accommodated because of their extra length. This is of course rubbish since the ever adaptable Spitfire easily accommodated the very much longer two speed two stage Merlins and even the two...

I took a quick look at your Mustang page and I think you made some simple errors. The combat weight of a P-51D (the first version with six .50 caliber Browning M2 machine guns) was over 8000 lbs. The usual .50caliber API round weighed 43 grams which I think is about 0.01 lbs. not 0.1 lbs. The M2...

Did the 605D really have a three valve head? I can't find any reference to this type of significant change in any of the english language books and articles I have.

In the January 2013 issue of Cycle World Kevin Cameron describes BMWs' new clean sheet of paper R1200GS motorcycle engine. In addition to a lot of very state of the art tech it has side by side connecting rods and a balance shaft to damp the piston-inertia forces that twist the engine back and...

The Japanese experienced significant weight gains in the aircraft they were redesigned to utilize wood. The Russians found that in addition to weight loss they had more internal volume and could fit larger fuel tanks. Wood simply creates too many compromises because it is strongest in...

The AAC wanted to go with small single engine pursuits as late as Circular Proposal CP39-770 in the late summer of 1939. Curtiss proposed the XP-46 and Republic the Allison powered P-47 for this RFP. Fortunately information on the war in Europe nixed the light fighter concept and Republic was...

There was an Army Air Corps bias for turbosuperchargers and against mechanical superchargers in the 1930s that meant no AAC funding for mechanical two stage superchargers. The U.S. was the only country to mass produce turbosuperchargers during the war - so in one respect this policy was a...

I was wrong Gumbyk and Shortround6 are correct in stating that compression ratios in staged superchargers are multiplied. The compression ratios are so low in these engines that is easy to make that mistake (i.e. 2x2= 4, 2+2=4).

BMW recent book "BMW aero engines" states in several places that the BMW 139 was a 14 cylinder engine. It lists the dimensions of the cylinders as 155.5 mm by 155.0 mm (very close to HoHuns' source) which gives 41.2 litres in 14 cylinders or 52.98 litres in 18 cylinders. I think it's obvious...

I believe the compression ratios are added not multiplied, i.e. two 5:1 stages would result in a 10:1 overall compression. In a slide prepared for his paper "Gas Turbines for Aircraft Propulsion" Sir Stanley Hooker shows the Merlin 61 having a maximum compression ratio of about 6.5:1 compared to...

Thanks Krabat42, mudpuppy and johnbr. I did find the BMW Aero Engines book on the Schmidt website and have ordrered it for Christmas. Too bad it is not available from North American sources. I guess Amazon et al are reluctant to sell sometging that is over $100.00 US. The big book sellers would...

Any news on BMW Aero Engines? I have been looking for it since June and can't find it in the U.S.A. or Canada.

Oh sure the Merlin , how common, how mundane. But think about it, the Merlin qualifies in all three catagories. 1. The great technical breaktroughs. The Merlin 60 series multi speed common shaft two stage supercharger with liquid to air charge cooling was the most important technological...

I think the DB 603 was a politically incorrect "private venture" that the political managers in LRM never warmed to. I think the LRM would have perferred DB to perfect the 606 and 610 double engines and saw the 603 as an unecessary distraction. Certainly as the war dragged on DB had more than...

Thanks Saburo this is a timeless classic. We have come a long way since then.