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And that is probably true and that is where the design negotiation comes down between the aerodynamicists and systems engineers of how much is lost in performance vs. an easy system function.I think they have some actual studies or estimates on the open wheel well issue, for the Spitfire and a couple other planes (Wildcat?) I'm not sure where to find those though.
They do but is also depends where on the aircraft they are located. When I crewed an aircraft at the Reno Air Races we removed as much "stuff" from the airstream as possible and also taped up seams and fairings. IIRC everything forward of the Mean Aerodynamic Chord (MAC) was the most critical.Drag is hard to calculate but small things (radio masts for example) seem to sometimes make a big difference.
It may be "possible", it it worth the cost? and there are a lot of costs.proves that the more conventional landing gear (with fully covered wheels) was certainly possible.
How much difference between those two P-40s? Unless you have wind tunnel results everything is a guess. Since the short nose P-40 moved the prop hub up 6 inches compared to the long nose the radiator/oil cooler area didn't actually change that much. The distance from the top of the cowl to the bottom of the cowl/duct changed very little if at all.And I'm not saying the P-40 was a flying brick either, by any means, but it certainly could be improved. In terms of drag, there is a lot of difference between these two P-40s
They do, the difference is speed is not expressed well when you are using mph unless the planes are flying at about the same speed at about the same altitude. Saying change Q on Spitfire is worth 6mph flying 375mph at 20,000ft is the same as change Q adding 6mph to a P-40 flying at 330mph at 10,000ft has got two variables thrown in.Drag is hard to calculate but small things (radio masts for example) seem to sometimes make a big difference.
If the Ozhawk making was 1100hp at 20,000ft with just a two speed supercharger would be a miracle worthy of witnessing by the Pope and every other religious leader of the time.An Ozhawk with a two speed supercharger might be a little slow, but if it's still producing say 1,100 hp at 20,000 ft, before 1943, that could fit into a niche that the Allies did not have very well covered except by the P-38 and Corsair which were in small numbers and still dealing with teething problems. A Ozhawk with a two stage R-1830 could of course be even better.
Ok This is total confusion. The difference between the FM-1 Wildcat and the FN-2 Wildcat had very little to do with the octane of the fuel.Conversely, with the availability of higher octane fuel, an "Ozhawk' with a low altitude but extra 'peppy' 1350 hp R-1830-65 like the FM-2 could make for a very nice interceptor and low altitude fighter I think.
Getting back to the "Ozhawk" - while I agree it wouldn't be as fast as a Tomahawk or a Kittyhawk, I think the potential of a two speed or a two stage engine R-1830 could bring some very welcome capability to the Allied forces in the Pacific in particular, assuming (and this is of course, a big if) they could get it working soon enough. When did they have them in Beauforts exactly?
P & W did come out with a Peppy 1350hp version of the R-1830 in 1944 but it did require a number of things to be changed and not just pouring different fuel in the tank.
One thing they did was copy the cylinder construction method used for the R-2800C (from the P-47M) for better cooling. There were other changes.
I am going by the list of R-1830 engines on Enginehistory.org.Right from the start of production because at some point first 90 Beauforts were supposed to be for RAF with R-1830 S3C4G (two speed supercharger, import from overseas), next 90 for RAAF with R-1830 S1C3G (single speed supercharger, engine produced in Australia). Anyway, first Beaufort with Twin Wasp (two speed supercharger) was delivered to RAAF in September 1941. If I remeber well, in January 1942 when they were discusions about Boomerang some 90-ish Twin Wasps with two speed supercharger were in Australia and at least 300 more ordered for delivery.
Interesting, do you please have more details about those changes?
USAAF cleared regular R-1830 S3C4G (aka R-1830-90B) for 1350 hp in 1944, Boomerang was tested with this War Emergency Power rating. It didn't work on Boomerang because of cooling issues.
It may be "possible", it it worth the cost? and there are a lot of costs.
How much difference between those two P-40s? Unless you have wind tunnel results everything is a guess. Since the short nose P-40 moved the prop hub up 6 inches compared to the long nose the radiator/oil cooler area didn't actually change that much. The distance from the top of the cowl to the bottom of the cowl/duct changed very little if at all.
In one test a P-40B (that is a P-40C in the picture) did the following in comparison to a P-40D (Picture is a long tail P-40F or L with Merlin which did a have bit bigger scoop)
P-40B.................15,000ft....................352mph................1090hp/3000rpm
P-40B..................15,000ft...................310mph.................720hp/2280rpm
P-40D.................15,175ft...................354mph.................1085hp/3000rpm
P-40D.................15,175ft...................307.5mph...............725hp/2280rpm
That certainly looks like within under 2% difference to me
Now please note that the power is estimates based off the rpm and boost pressure and the atmosphere (temperature and pressure).
Many radial engines had torque meters and they could actual measure the power in flight, the V-12s could not do that.
They do, the difference is speed is not expressed well when you are using mph unless the planes are flying at about the same speed at about the same altitude. Saying change Q on Spitfire is worth 6mph flying 375mph at 20,000ft is the same as change Q adding 6mph to a P-40 flying at 330mph at 10,000ft has got two variables thrown in.
1,000 hp at 19,000 ft, even if that really is the best they could get out of it (I'm not sure I buy that), is still actually pretty good. It's about what the two early P-40s you listed above were getting at 5 km lower. That much power at 19 or 20,000 feet means probably pretty good speed at that altitude. That would be pretty helpful. For example in the kind of situation they faced when Darwin was being bombed.If the Ozhawk making was 1100hp at 20,000ft with just a two speed supercharger would be a miracle worthy of witnessing by the Pope and every other religious leader of the time.
A P & W R-1830 with a two speed supercharger was good for 1050hp at 2700rpm at 13,100ft. You are going to loose approximately 2% for every 1000ftof altitude so expect about 900hp at 20,000ft.
That was the whole reason for using the two stage supercharge in the first place. And there were some limits to the two stage supercharger as used in the F4F.
P & W seems never to have rated the engine at "Military power" That was the Navy's doing.
P & W rated the -86 engine at 1200hp at 2700rpm for take-off.
they also rated it "normal" max continuous at
1100hp/2550rpm at 3500ft
1050hp/2550rpm at 11,000ft
1000hp/2550rpm at 19,000ft.
Ok This is total confusion. The difference between the FM-1 Wildcat and the FN-2 Wildcat had very little to do with the octane of the fuel.
The extra "peppy" 1350hp engine in the FM-2 was not a P & W engine, it was a Wright R-1820-56W Cyclone 9 cylinder engine that used water injection.
Trying to manufacture Wright Cyclone 9s on machinery that made P & W 14 cylinder Twin Wasps was going to take a bit of doing.
Before anybody gets a bright ideas of using the Wright Cyclone 9 for Australian production instead of the R-1830 Wasp the 1300-1350 Cyclones 9s used in the FM-2 were a totally new engine that shared just about zero parts with the 1200hp Cyclone 9 that came before it. New cylinders, new cylinder heads, new crankcase, new crankshaft and so on.
P & W did come out with a Peppy 1350hp version of the R-1830 in 1944 but it did require a number of things to be changed and not just pouring different fuel in the tank.
One thing they did was copy the cylinder construction method used for the R-2800C (from the P-47M) for better cooling. There were other changes.
I'll take your word for it. But 1) by 1943 Australia is starting to produce two stage engines for the Beauforts, right?
Even in what you are suggesting, you'd be wrong, but you made a mistake, look at those two aircraft in the photo again.
...is for sure reflecting a 'heavy' laden aircraft flown at low boost, probably continuous rated power, maybe with a belly tank?. The other very thorough Australian test I posted a couple of posts back shows far better performance, starting at 300 mph at Sea level and going up to 348 mph at 12,300. And this is a heavily laden plane at (8600 lbs) and flying at only military power (44" Hg). It also started climbing with 2000 fpm which rate continued until 9,500 ft. (this was at only 39" Hg power setting). The fact that the ROC remained the same up to that height is a good indicator more power was available.
I'll take your word for it. But 1) by 1943 Australia is starting to produce two stage engines for the Beauforts, right?
What mistake did he make?
No, altough nearly 1000 Twin Wasps were made in Australia, they never produced R-1830 with two stage or two speed supercharger. Australia was only building version R-1830 S1C3G with single speed single stage supercharger in two variants - engines serial Nos.1 to 581 inclusive were originaly fitted with coupled (rigid) reduction gear drives (US designation for this variant was R-1830-82), engine serial No. 582 and subsequent were fitted with de-coupled (splined) reduction gear drives (US designation R-1830-90).
Ah ok, so they imported the 2 speed or 2 stage engines for the Beauforts?
Here is a link to the P & W R-1830 engine index.
It should cover all the versions of the R-1830 made by P & W and their licensees.
Not sure about Swedish engines as they were licensed after the fact.
Please read the notes as some of them were planed or proposed engines or tested but not manufactured/sold.
Like any list this big there may be the occasional typo/misprint.
Apparently this phraseThe more modern looking one is a P-40F. Three feet longer, no nose gun farings, no nose scoop, and a lot of minor improvements.
Neither index has all the information we might like but the USAF engine models
Is just that, USAF engine models.
No navy engines and no commercial engines.
I could be wrong but I believe all the 1350hp engines in the P & W list are listed at 2800rpm.
The USAF list has quite a number of discrepancies.
Apparently this phrase
" (Picture is a long tail P-40F or L with Merlin which did a have bit bigger scoop)
isn't enough to explain the difference in between the P-40D that data applied to and P-40 in the picture.
Now was there one error or two in this sentence?
"The more modern looking one is a P-40F. Three feet longer, no nose gun farings, no nose scoop, and a lot of minor improvements."
Or is there 3 errors if you are comparing a P-40D to a P-40F?