Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Were any USAAF studies or prototypes made of trying to fit the APS-4 radar into a single place fighter like the P-51 or P-47, similar to the deployment in the F4U-4N or F6F-3N. The P-38M was late to the War.
The night fighter version of the Douglass A20 Havoc known as the P70 might have been fitted with PW R-2800 engines. With 18% more power and less drag due to the smaller diameter engines it should have a decent performance. I suspect 350mph. Fitting navy two stage supercharger engines even more. The A26 Invader seems a good candidate as well.
The Germans tried radar on the Me 109 and Fw 190. The pilot could tell range and approximately who far up/down left/right the target was but they found staring into an abstract oscilloscope destroyed his precious night vision. I really don't know how the USN got around this. The radar would have to be so good the pilot didn't need night vision.
And you would need to redesign the nacelle to reduce the frontal area - probably not going to help because the MLG pretty much fills the nacelle.The difference in diameter is 2.2 inches.
We used to put lightly exposed radiographic film over the screen to darken it but it only partly solves the issue, I could still see a green line for hours after finishing work every time I shut my eyes.
BiffF15 Having been "disturbed" recently by Typhoons on exercise Crimson Warrior which always involved flights at night, how does the pilot use a head up display at night, doesn't it eliminate the use of eyes to see anything outside of the plane? From what I know and have experienced about human night vision, it is better than most people think it is because very few people use it. As I understand it, it takes 20-30 minutes for eyes to become used to very low light and only a seconds use of artificial light to take you back to needing that 20-30 minutes again. For a while when I was training, I had to develop macro photographs that had to be developed under minimum safelight conditions (no red light as you see in the movies). To be honest it was easier to literally learn to do it with your eyes closed, like a truly blind person, than wait the 20 minutes needed for your eyes to pick up what little could be seen.
2.2 inches is a 5% reduction in diameter results in a 10% reduction in frontal area and therefore 10% less drag. It is substantial.The difference in diameter is 2.2 inches.
When you use the diameters to calculate the area it is a 8% difference.2.2 inches is a 5% reduction in diameter results in a 10% reduction in frontal area and therefore 10% less drag. It is substantial.
Then there is the 18% to 30% increase in power In addition to options such as water injection and two stage superchargers.
Maybe because the other guy was talking about an A-20 with R-2800s, a plane that never existed.Why do you keep mentioning performance for an a/c that never saw combat?
The first P-61C aircraft was accepted by the USAAF in July of 1945. However, the war in the Pacific ended before any P-61Cs could see combat. The forty-first and last P-61C-1-NO was accepted on January 28, 1946. At least thirteen more were completed by Northrop but were scrapped before they could be delivered to the USAAF. Northrop records show an additional 400 P-61Cs with 1945 serial numbers to have been on order, with blocks 5 and 10 being at least in the planning stages.
And if you cannot slim nacelle because of the MLG and other things that hide there then the reduction in area is zero.When you use the diameters to calculate the area it is a 8% difference.
AAF Manual 45-59-1 Security Classification and Selected Data on AAF Aircraft and Equipment dated August 1945
I think the oft-quoted figures touting P-61 performance are slightly off. AAF Manual 45-59-1 Security Classification and Selected Data on AAF Aircraft and Equipment dated August 1945 was, itself, formerly classified Confidential. Page 23 describes the P-61A and P-61B with the unclassified max speed as "Over 375 mph." Critically, the classified max speed is listed as 363 mph 15,000 feet (formerly Restricted). What matters to me is that the P-61 was the only aircraft in the document to list a classified max speed lower than the unclassified max speed.
Another note explains that the P-61C will have the CH-5 turbo-supercharger for high altitude performance. No projected high speed is listed, but internal memos note that the P-61C's actual high speeds were dismally below projections.
Cheers,
Dana
When you use the diameters to calculate the area it is a 8% difference.
You also have to take into account that the A-20 was a generation behind the View attachment 601986P-61 in aerodynamics. Remember the A-26 used R-2800s but also had much better aerodynamics as a next generation design, yet managed only 42MPH more, 317mph to 359MPH on 800 more HP; hardly competition for the P-61's 366 to 430MPH. In fact, a version of the A-26 was evaluated as a night fighter and rejected in favour of the P-61.
The P-61 had two stage intercooled superchargers (originally developed for the US Navy) while the A-26 had single stage superchargers. Latter version of the A26 managed over 400mph. The superior speed of the P-61 over the A26 comes almost certinly down mainly to the P-61 being able to maintain power to higher altitude. The altitude of maximum speed suggests this (16000ft versus 20,000ft).
The R-2800 appears to be about 300lbs heavier than the R-2600 but I suggest it is within the capacity of the A20 to handle especially as the bomb bay would not be used.