drgondog
Major
Define "noticeably faster" and separate Induced Drag increases due to more GW? Stick with P-38J-5/-10 comparison because earlier versions couldn't exploit the extra HP yet.
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Define "noticeably faster" and separate Induced Drag increases due to more GW? Stick with P-38J-5/-10 comparison because earlier versions couldn't exploit the extra HP yet.Hello Tomo Pauk,
This seems like a pretty minor difference for some potentially great reductions in drag: The Mustang and other aircraft with radiators and oil coolers located very far aft on the fuselage all have longer tubes for oil or coolant but the aft radiator location seems to be the optimal setup. Note that this was done even for the oil cooler on the La-7 which had its oil cooler moved quite a bit further aft than on La-5FN.
The P-38 Lightning also had rather long coolant lines back to its radiators.
Hello drgondog,
I can't recall the source, but I have seen a mention that at the same cruise power settings, the earlier aircraft were noticeably faster so there was a significant difference in drag in the new intercooler setup. The maximum speed of the later aircraft was much increased because they were able to run higher sustained maximum power settings because of the increased efficiency of these same improved intercoolers.
- Ivan.
That bad?Major re-design and re-tool - perhaps a year's delay in production that War Production Board would never approve.
There were a huge number of plane types that weren't improved when they could have been because it would have resulted in less planes in service. Changes to design especially when un planned and not researched can cause huge losses in production.That bad?
I was also thinking of something else: The XP-49 was an all new design, and originally built to use the X-1800 engine (H-2240/2600), and ended up using the XI-1430. I'm curious why they'd put the XI-1430 in there? It was less powerful than the X-1800 (XI-1430 = 1600 HP), which produced around 2000 horsepower.
Why not put the H-2470 in there? It was actually a little bit shorter than the X-1800 (91.13 vs 107) and produced more power (2300).
I think you might be right, my source (admittedly, Wikipedia, but I think it's still right) seems to say that the H-2470 was conceived when the O-1230 proved uncompetitive in power-output.The H-2470 may not have existed at that time.
Proposed in 1939The XP-49 was not an all-new design since it used the P-38's wing.
What problems affected the Tornado?XP-49 prototype was to have XH-2600s installed, but production aircraft were to have the R-2160 Tornado.
Proposed in 1939
Not may post.Could the tailcone extension have been fitted?
Okay, here's something a bit older: The Y1P-37.
Looking at the basics of the design...
I'm not sure if the intercooler is liquid/air or air/air because, while air/air is normal; the two are so close to each other, I can't really tell the exact details.
- The wings and landing-gear seem basically the same as the P-36: That's good. They were aerodynamically and structurally sound.
- The turbocharger didn't appear to be placed in a bad location: This is good, it takes up little space
- Main fuel tanks appear to be in the inboard-wings: This is good. It seems to provide adequate capacity, while simultaneously not taking up excessive space in the plane.
- The auxiliary fuel tank is positioned behind the intercooler, and in front of the cockpit: This is bad. While it was based on the P-36, the P-36 had a compact radial engine up front, not a long inline engine; it also did not have any intercoolers (or radiators) to deal with.
- Possible remedy: Reposition the auxiliary tank behind the pilot, as was done on the later P-40. While I'm not sure what the USAAC regs were over the years, there is physical room for it.
- The intercooler/radiators are positioned behind the engine: This is bad as this adds length behind the engine, and ahead of the nose
The P-40 had the auxiliary tank behind the pilot. I'm not sure if it was designed to use this tank in combat or for ferrying. Regardless, it worked okay, from what it appears.Putting the aux fuel tank so far aft will result in a large shift in C of G as fuel is burnt off. It is best if all consumables (fuel, ammunition) are located as close to the centre of gravity as possible.
Well, yeah, but you have to see over the nose too...Increasing intercooler pipe length adds inefficiencies to the system
The P-40 had the auxiliary tank behind the pilot. I'm not sure if it was designed to use this tank in combat or for ferrying. Regardless, it worked okay, from what it appears.
Is that intercooler liquid/air or air/air? Looking at the diagram, I can't really tell as it's so close to the main radiator.
The P-40 had the auxiliary tank behind the pilot. I'm not sure if it was designed to use this tank in combat or for ferrying. Regardless, it worked okay, from what it appears.
Yes, but if the radiator and intercooler layout were altered, it would allow the cockpit to be more conventionally forward. This would produce a shape similar to the P-40.The pilot is so far back that moving a fuel tank behind the pilot would be bad.
ThanksIt is an air-to-air intercooler.
I assume you mean the intercooler radiator? Sounds silly, but air-to-air intercoolers do have an intake.The big improvement to the YP-37 would be changing the position of the coolers. You could put the intercooler ahead of the turbo, under the chin.
That looks like it would be workable.The radiator would then have to go under the wings or on the leading edge of the wings.
I assume you mean the intercooler radiator? Sounds silly, but air-to-air intercoolers do have an intake.
As I understand it, an intercooler includes air drawn in from the outside, and cycled through tubes/grills/passageways (a radiator) which absorb the heat from the air passing through the carburetor intake on the way to the engine. The heat from the carburetor is transferred to the airflow in the intercooler, which then is routed overboard.I mean the intercooler. With an air-to-air there is no need for a secondary radiator.
Makes sense, but I'm figuring the turbo has hot exhaust gas flowing out of it. If the duct was like the P-38J, wouldn't the air get cooled off, then heated up by a whole bunch of hot exhaust gas blowing in (this might sound stupid, but it's 2 AM so my thinking might not be all that perfect)?I was thinking along the lines of the intercooler placement on the P-38J/L.
As I understand it, an intercooler includes air drawn in from the outside, and cycled through tubes/grills/passageways (a radiator) which absorb the heat from the air passing through the carburetor intake on the way to the engine. The heat from the carburetor is transferred to the airflow in the intercooler, which then is routed overboard.
So the intercooler is a radiator, it gets it's coolant from the outside if it's an air/air intercooler.
Makes sense, but I'm figuring the turbo has hot exhaust gas flowing out of it. If the duct was like the P-38J, wouldn't the air get cooled off, then heated up by a whole bunch of hot exhaust gas blowing in (this might sound stupid, but it's 2 AM so my thinking might not be all that perfect)?
Would it be possible to bifurcate the duct around it without too much increase in frontal area, or mount the turbo on its side?