Stuka vs. Dauntless vs. Val vs. Skua vs. Il-2?

[Trav02]

Trouble with the Spit is they picked up speed too fast in the dive.

/\This. Some other issues too. Great writeup here...
SPITBOMBER — Vintage Wings of Canada

 

[tomo pauk]

for the 1939 Suizei class of bombers is that only 2 countries had a 1000hp/15,000ft engine. a few others had works in progress. and there were few hiccups.

Britain, got the 1000hp engine, doesn't have enough propellers or at least good ones.

Britain had no problems in installing the good propellers on their bombers, so they should be okay. There is a lot of dead or obsolescent wood around that deserves the axe, so our brave new fast bomber materializes.

France, no 1000hp engine, working on it.
Italy, no 1000hp engine.
Japan, no 1000 hp engine (license signed in 1938, Prototype D4Ys used imported DB 600s in 1941, production planes in 1942, a little late)
Soviet Union. M-103s or a handful of M-104s? According to one source 50 M-105s built by the end of 1940.
US, 1000hp engine in 1939? got the design, got 40 engines by New Years Day 1940. rebuilding several hundred engines in the summer/fall of 1940 to meet spec.

France, Italy and USA can try with the V12s they have, and concurrently have the versions with the 1000 HP radials in the nose.

(BTW - anyone knows why the much smaller MB.152 was that much slower than the Re.2000, despite both having the similar engine with similar power? was it because the prop shaft was skewed against the aircraft datum line?)

Yes, this is a workaround so there is a fast-ish bomber until the V12-powered version is, hopefully, around; not really 320-330 mph turn of speed, but already ~300 mph is a boon when compared with light bombers these countries had in production in 1939-40.
Yes, Soviets have probably the best bet in the M-103.

With 1000hp engines there is only so much trading off you can do. With 1300-1400hp engines you can do a lot more because a lot of you other "payload" is the same.
Two man crew (?) 200kg, cockpit structure, instruments, 50-70kg of radio gear, rear gun? crew armor.
All the same for the 1000hp plane and the 1400hp plane (or mostly) so you have more power to get the bombs and fuel off the ground even if you use a bit bigger wing.

Trick with 1300-1400 HP engines is that it took a while for these to became available in good numbers and reliable for 1-engine multi-hour tasks. We can retrofit a lot of these engines in the legacy airframes, though, so I'd still suggest that 1st go is with 1000 HP types, so these can be had early in the war.

US has the best chance at a semi fast radial engine bomber
The R-1830 offers about 1000hp at 14,500ft with a two speed supercharger and some abuse to the engine. At least the engine is under 50 in (1.27m). A 55in radial engine has about 20% more frontal area.

Americans can mimic what they did with when the DB-7 morphed into the A-20: start with R-1830, with a quick follow-up with the R-2600. Re-engining it with a V-1710 - P-36 into P-40 style - is also an option.
Or, start with the R-2600 from the get go, and re-engine it with the R-2800 when this engine is available. Obviously, the second type will start as a bigger A/C than the 1st type, perhaps 280-300 sq ft vs. 250-270 sq ft?

Also the rate of progress for somethings was rather quick in some ways and not so quick in others. It took about about 8 years for the US to go from installing flaps on the P-26 to the Douglas A-26 flying with double slotted flaps (another 2 years to go into service). Sometimes if you start too early you are stuck with old airfoils, structures and systems.

Americans were making wings for military aircraft in 15-16% t-t-c ratio (root) before 1939, and were also using newer airfoils. This is fine for the whole war.
Lockheed have had Fowler flaps in service by late 1937, so there is a precedent for these.

 

[tomo pauk]

Again, what do you want the plane to do?
dive bombing caught peoples imagination, how practical it was for 'close support' is subject to question. Trying to spot targets in woods/forest from 10-12,000ft is not easy. It isn't easy trying to do it from under 500ft either.
Bombing stuff in the desert or in large grass lands is a lot easier.

Attack the targets that are well visible. Like columns of vehicles and/or men on the roads, artillery units, bridges, ships. Plane should be capable of dive bombing, since that is probably the only realistic way to hit small and/or elusive targets, that are well defended, like ships or bridges. Attack enemy airfields and troop concentrations, as well as known fixed postitions.

Trying to spot troops in woods/forest was tricky for everyone.

 

[bf109xxl]

Soviet Union. M-103s or a handful of M-104s? According to one source 50 M-105s built by the end of 1940.

M-62(1040 hp), M-63 (1100hp), M-88(R, 1100hp) - mass production in 1939, M-87(950hp) - in 1938.
The Soviets developed a number of multirole aircraft with similar characteristics as SBD (the "Ivánov" program: ANT-51 - future Su-2 - and Polikarpov's "Ivanov"). However they were not suited for dive bombing which was definitely underestimated by the Soviets. However even having dive bomber (Pe-2), the Soviets were not able to use it efficiently. Dive bombing was rather seldom used, few bomber regiments were able to bomb from a dive in a group - indeed the Pe-2 was used mainly as a level bomber with mediocre performance. Stukas and SBD required well trained pilots, I am not sure that this problem could be solved by the Soviets in 1939-1940 (I am rather sure that it was absolutely impossible). But the Soviets had a pretty good twin-engine dive bomber, superior to any single-engine bomber (Polikarpov's SPB). Because of the stupidity of the Soviet system, it was not put into mass production.
The Su-2 was not bad, it even suffered fewer relative losses than the Pe-2 in 1942 - the average training of Su-2 pilots was higher, they gained combat experience, but this airplane had no future in any role on the Eastern Front - neither as a light bomber nor as a dive bomber.

 

[tomo pauk]

M-62(1040 hp), M-63 (1100hp), M-88(R, 1100hp) - mass production in 1939, M-87(950hp) - in 1938.

Note that stipulated altitude is 15000 ft, ie. about 4500m. Here the M-62 and -63 don't break the 900 HP mark, so a nod against these.
A 9 cyl engine will have more drag than the 14 cyl engine of the same power and day, and much more drag than a V12. A V12 will also get more help with the exhaust thrust in the installations from 1939.
The two/three minuses combined mean that M-62 and M-63 should've been avoided on a fast-ish bomber, that SR6 and I were discussing a few pages on now.

The M-87 would've been a tad better than the 9 cylinders, without the bulk and with a bit more power (950 HP at 4.5 km).

Good source for M-88(B?) being in mass production in 1939?

 

[bf109xxl]

Note that stipulated altitude is 15000 ft, ie. about 4500m. Here the M-62 and -63 don't break the 900 HP mark, so a nod against these.

Ok, but is it principal? SZ-2 M-62 (pre-Su-2) reached 403 kph at 4700m. It could take up to 500 kg bomb loading (2xFAB-250), but it was not tested in this configuration - a new engine type was installed.

A 9 cyl engine will have more drag than the 14 cyl engine of the same power and day, and much more drag than a V12. A V12 will also get more help with the exhaust thrust in the installations from 1939.
The two/three minuses combined mean that M-62 and M-63 should've been avoided on a fast-ish bomber, that SR6 and I were discussing a few pages on now.

The I-207 equipped with M-63 could be used as a dive bomber like SBD. Or even more efficient taking into account its size and weight characteristics. SBD was not optimal for the Soviets. They needed either a good level bomber (Tu-2) or a fighter-bomber for dive bombing. The story of the Su-2 clearly demonstrates it.

The M-87 would've been a tad better than the 9 cylinders, without the bulk and with a bit more power (950 HP at 4.5 km).

468 kph at 5200m - not bad for April, 1939.

Good source for M-88(B?) being in mass production in 1939?

"Russian Piston Aero Engines" by V.Kotelnikov

 

[tomo pauk]

"Russian Piston Aero Engines" by V.Kotelnikov

Okay, thank you.