Recent content by peril

I set Javafoil polars to transition model 'xfoil after 1991'. I usually have no problems getting results, ensure closed trailing edge. If still having issues play with reducing max number of plotted points.

Airfoil was NN-21, work I have done in finding a NACA equivalent is based on data for NN series from Ki-27 maru book. Whilst not definitive it is the best I have been able to achieve given the few clues in text. Root was 16.5%, tip 8% NN-21. GoG / MAC location unknown at this time. Estimated...

Um Jerry, English does not a mechanic make, back to the topic at hand. I'd recommend a copy of the book 'Vee's for Victory!'. As an overall insight into the Allison 1710 series and it's design, it cannot be beaten. You won't be disappointed, I love my copy.

;) Bump.

Were any Japanese planes fitted with automatic thermostatically controlled cooling gills? I ponder how sophisticated the Japanese planes became in relieving pilot workloads. Or were they all manually operated by the pilot to keep things simple to build? Thanks for any info on this.

Yes Hohun, I thought of that too, what about the issues with compression and roll rates. P38 is NO dream boat either ;) hehehe.

Frankly, the reason given most often I see is Weight, the J4M (turbo) was 200kgs heavier. Weight costs maneuverability and payload.

Again we see the Merlin 45 producing more hp above 14,000ft than the high alt rated Merlin 46. Of note above is the rated power difference between the 46 47, most likely accounting for the loss of power to the cabin pressure drive, although this is the first reference to show that difference...

Jerry, does your Merlin book show information on the Merlin 46/47?

I just think they didn't draw it well, it actually looks correct if you extend the below FTH line over the Merlin 3 orange. With a constant 3000rpm this would be correct Merlin 45 or a 46/47 and shows the same engine curve with an increase in boost limits in 1942. 1942 looks like the +16...

Yes Dairwin, that is how I understand it as well. The larger SC would require more power and thus costs SL hp, but the bonus is a more hp at higher alts. I have that 24 curve as well but it's not useful with this case.

OK, when you change the SC properties your resultant FTH curve will move. You are right in that only the size changed and ratio remained unchanged (my error from dealing with lots of engines lately). However this change from my understanding would logically be to improve the Merlin 46 curve...

Ah, yes that might make sense, ATM I also have an excess in climb at this 45 power curve (1515h) of ~250-300fpm over tested +16, +18 would explain a lot but it would be nice to have an official Merlin chart that confirmed this. Rated alts Merlin 45 vs 46/47 is still a concern, I would like to...

RAM increases alt at which the boost level chosen is available. It does not increase hp if measured at the same alt as static on SC engines.

I'm here, bit busy but around, this is the kind of stuff I want to see. Thanks for this, my concern is did RAAF have neg "G" issues in their first shipment of Spit VCs seeing that they are listed as Merlin 40 series no 50s. I understand retro fitting may have occurred, but how do we know for sure??