F8F Bearcat derived from FW190?
- Thread starter Navalwarrior
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Shortround6
Major General
What many books, websites and magazine articles miss is that many of the later radial engine installations made use of exhaust thrust. Some better than others but it doesn't take much to be better than
Gee, lets use a whacking big exhaust collector so the exhaust has room to expand and loose pressure/velocity. Let's route the exhaust collector where it catches the greatest amount of cold high speed airflow to further cool/drop the pressure of the exhaust gases. Lets also throw in some bends/ curves to further slow down the exhaust gases. And to finish off, we will point the exhaust outlets at about 30-45 degrees from the airplanes line of flight so some of the exhaust gas thrust is trying to lift the front end of the airplane rather than drive it forward.
Yeah, I am taking full advantage of 20/20 hindsight. (and there may have been a shroud over the exhaust collector at the front edge of the nacelle) but obviously there were a lot of things that could be changed between most peoples 1938-39 radial engine installations and the FW 190 and even more that were changed form the Fw 190 to the installations used in 1945.
Gee, lets use a whacking big exhaust collector so the exhaust has room to expand and loose pressure/velocity. Let's route the exhaust collector where it catches the greatest amount of cold high speed airflow to further cool/drop the pressure of the exhaust gases. Lets also throw in some bends/ curves to further slow down the exhaust gases. And to finish off, we will point the exhaust outlets at about 30-45 degrees from the airplanes line of flight so some of the exhaust gas thrust is trying to lift the front end of the airplane rather than drive it forward.
Yeah, I am taking full advantage of 20/20 hindsight. (and there may have been a shroud over the exhaust collector at the front edge of the nacelle) but obviously there were a lot of things that could be changed between most peoples 1938-39 radial engine installations and the FW 190 and even more that were changed form the Fw 190 to the installations used in 1945.
fubar57
General
Ugly wee beast
Shortround6
Major General
To try to be fair about the only things the Americans were doing different at the time was not using the front of the nacelle as the exhaust collector.
9-14 cylinders grouped into one big manifold with one or two exits. Lots of bends. Exhaust outlet/s seldom aligned with the direction of flight of the aircraft. Or if it was they added another few feet of pipe.
P-36 without the streamline shrouds for the exhaust pipes.
Pipe appears to be cut through the bend and the majority of the gases will be trying to go down.
9-14 cylinders grouped into one big manifold with one or two exits. Lots of bends. Exhaust outlet/s seldom aligned with the direction of flight of the aircraft. Or if it was they added another few feet of pipe.
P-36 without the streamline shrouds for the exhaust pipes.
Pipe appears to be cut through the bend and the majority of the gases will be trying to go down.
Shortround6
Major General
That may be an FM-2 with the 9 cylinder Wright?
The F4F-3 and at least the early F4F-4 used similar pipes to the P-36
I have, but at the time I didn't make the connection. Willy, a warbird restoration guy, and I were chatting about the Sea Fury and Bearcat (prolly Reno related) when he surprised me with "both the Sea Fury and Bearcat weren't just influenced by the FW-190, both aircraft took engineering and design cues from the 190." He made it sound factual although I never pressed him for a source, likely bc I didn't agree. Wish I had (suppose I could call him), cuz it comes up from time to time, and I see a faint resemblance. If I squint.
kool kitty89
Senior Master Sergeant
If this hasn't already shown up elsewhere on the forums in the last few years, here's also this more comprehensive (and tabulated) NACA report on the XP-42 tests here:
Also an archived link for that XP-42 picture (since the crgis.ndc.nasa.gov site seems to have purged some of their pages in recent years).
Curtiss XP-42 : NASA/Langley Research Center (NASA-LaRC) : Free Download, Borrow, and Streaming : Internet Archive
Curtiss XP-42: This highly modified Curtiss P-36A became the XP-42 when it was re-engined and took part in drag-reduction and all-moving tail research with the...
archive.org
I don't think it came up in the thread earlier, but the airfoil the FW 190 used was already the same high lift NACA 23000 series that had been favored on US Navy aircraft for quite some time and was chosen for all the monoplane fighter aircraft the USN and USMC adopted or used during WWII (F2A, F4F, F4U, F6F, and F8F all used it, so that's something that obviously predated any knowledge (or existence) of the FW fighter itself. Granted the specific planform chosen for the F8F might be the closest to the 190 of those bunch, though I think the root thickness is still 18% more like most of those other Navy fighters and thicker than the 190s, which I think is 15%. And in terms of thickness and wing shape, the 190's wing is arguably closer to the P-36 or P-40, but with partially squared off wingtips and even less taper. (the low taper of the 190's wing likely related to the redesign from the earlier smaller area wing of similar span, but greater taper from early in its development program)
Given the style of cooling fan and spinner used in some configurations of the XP-42 program, I'd be more inclined to believe the XP-47J project borrowed some from that report or preliminary reports or more basic inspiration from what limited info Republic might have gotten during the XP-42 test program given the XP-47J's cowling, spinner, and fan design resemble that better than probably any other tight cowl or fan cooled radial configuration I've come across, and the timing is more or less right for that. Unlike the BMW 801's use of a separate gear drive for the cooling fan, a larger diameter fan with many more and finer blades were used on the XP-42 and XP-47J both apparently driven directly by the prop shaft at the same rotational speed. (the XP-47J program undoubtedly tested that configuration to higher mach numbers and either intentionally or incidentally uncovered the impact of that over the P-47's blunt nose, significantly increasing the critical mach number of the airframe; the mach limits and transonic drag caused by the P-47's cowling and nose/spinner shape is something that was noted in a post-war British evaluation of various fighter designs, though I don't recall which one off hand)
This is also why I'm inclined to trust the 500+ MPH figures at over 30,000 ft the XP-47J achieved in tests, which would be around .77 mach and above the limiting mach number of the P-47 and well into the realm where it normally suffered from compressability related control issues (which would likely have especially impacted the tail section given the shockwave would've centered around the nose and fuselage section before the wing all on top of additional shockwaves coming from the propeller tips going supersonic, at least in terms of tangential velocity: ie rotational tip speed would be around mach .95 but combined with forward velocity, the actual angular or tangential velocity would be closer to 1.2 mach with speed of sound at 660 mph)
Given the Bearcat's exceptional speed was achieved at more medium and low altitudes (where air is warmer and speed of sound is closer to 750-780 mph), and due to its thicker wing roots probably being a limiting factor, that sort of nose streamlining might not have been worth the added weight, complexity or slight power drain from the fan usage. (or from large cooling cuffs) Plus at sea level, flat out on a warm day, the prop tips of the F8F would struggle to hit Mach 1.0 so also not run into that issue.
Greg Boeser
2nd Lieutenant
One of my kids came home from school one day with a guide to writing a paper.
It listed newspapers as
primary sources.
GregP
Major
says 'Cannot load Facebook SDK. Disable any adblocker or tracking protection and try again'
chance for a snapshot?
GregP
Major
When I click it, it plays.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
No love here either. Wonky Wi-Fi and I'm using my phone.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
The video works on my crappy cellphone.
I know, I'm just as surprised as the rest of you.
I know, I'm just as surprised as the rest of you.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Elvis
Chief Master Sergeant
Video works on my Chromebook.
GreenKnight121
Senior Airman
- 738
- Mar 16, 2014
The video in post #57 (page 3) of this thread works fine.
ww2aircraft.net
Nice clear action shot of the MLG unfolding.
Here is the part to see:
View: https://youtu.be/qj6xCC3vues?t=42
F8F Bearcat derived from FW190?
you tube of F8F landing gear being tested in the hanger. Wheels are in wing root/fuselage.
ww2aircraft.net
Here is the part to see:
View: https://youtu.be/qj6xCC3vues?t=42
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