If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#101
|
|||
|
|||
Essential and Dispensible WW2 aircraft.
|
#102
|
|||
|
|||
Essential and Dispensible WW2 aircraft.
guy wrote:
Responding late, but a few points: On 18 Oct, 00:51, Dan Nafe wrote: In article . com, Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... ;- What has liquid cooled engines to do with intercoolers? Nothing. Highly supercharged engines (Pressure Ratio of more than 3.0) really benefit from removing as much of the heat that's generated by compressing that air as possible, though. Some airplanes used cold air (P-38, P-47, B-17, B-24, B-29) to do that, some (2 Stage Merlin) used liquid. And if liquid cooled engines are so bad why did every airforce want liquid cooled engines for their fighters in WW2 (except the USN)? Well, a couple or 3 reasons. With a smaller frontal area, it was felt that an inline engine would be more streamlined, reducing drag. It was also thought that a liquid cooled engine would have better heat rejection - you just wouldn't be able to run an air-cooled engine at high power due to insufficient cooling. and last, but not least, fashion happens as much in Aviation as it does anywhere else. Pointy airplanes look cool, so people like to design pointy airplanes. As it turns out, you lose most, if not all of the frontal area advantages of a liquid cooled engine because you need to have radiators sticking out in the breeze to keep the coolant temperature within tolerable limits. As an example, consider a comparison between the aircooled P-47, and it's liquid cooled British equivalents, the Typhoon and Tempest. They have almost the same frontal area. In the case of the Typhoon and Tempest, half of it is radiators. It's possible to build low drag cooling systems, like that of the P-51 (Especially the B models and up), but it requires long ducting to act as a diffuser, a large radiator that, because of the ducting, will have to be buried in the structure, and a converging outlet to accelerate the heated air. The idea that an air-cooled engine couldn't get rid of heat fast enough was based on the idea that you couldn't put enough fin area on a cylinder to get rid of the heat. In the U.S., both Wright and Pratt & Whitney developed methods of making fins thinner and closer together, and with special shapes,to give more cooling area. -- Pete Stickney Without data, all you have is an opinion |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Two essential items... | john smith | Piloting | 19 | December 26th 06 02:48 AM |
Delaware LLC Owned Aircraft California Based Aircraft | ChrisEllis | Piloting | 6 | January 17th 06 03:47 AM |
Commercial rating: complex aircraft required aircraft for practical test? | Marc J. Zeitlin | Piloting | 22 | November 24th 05 04:11 AM |
Exclusive Custom Home Plans, and Essential information about building your New Home | orange tree | Home Built | 4 | November 20th 05 04:37 PM |
Experience transitioning from C-172 to complex aircraft as potential first owned aircraft? | Jack Allison | Owning | 12 | June 14th 04 08:01 PM |