Two engine R-3350 powered bomber

Discussion in 'Aviation' started by gjs238, Mar 4, 2015.

  1. gjs238

    gjs238 Well-Known Member

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    What would it be capable of?
    Would it/could it have the performance to replace B-17's and B-24's or just a significant improvement over other two-engine types?
     
  2. Shortround6

    Shortround6 Well-Known Member

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    Kind of depends if they open up the cowlings (more drag) and/or sort out the engine problems.

    A twin with the engine problems the B-29 had harks back to the Manchester.

    And big twins have a problem with survive-ability in engine out situations.
     
  3. pbehn

    pbehn Well-Known Member

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    The manchester must be a special case. Its engine was supposed to produce up to 2000HP but only produced 1750 and was eventually derated to 1450HP. Loss of an engine resulted in trying to fly a medium/heavy bomber with 7 crew and bomb load on 1450HP which was little more than the output of the top rated front line S/E fighter at the time. I agree the point though.
     
  4. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Ideally, the bomber with two R-3350s should be able to do what was expected from the working Ju-288, with the working Jumo 222. However, if the design incorporates numerous defensive posts and crew, the result would be a combination of B-26 and Manchester - a bomber that will be useful, but nothing special.
    For how a bomber with non-turbo R-3350 might've looked, we might check out the Bristol Buckingham: bomb load on par with mid-war Mossie, slower, somewhat more range, has defensive armament.
     
  5. Shortround6

    Shortround6 Well-Known Member

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    The Buckingham's bomb bay would hold a smaller number of bombs than a B-17 or B-24 and it had less range and fewer defensive guns. A replacement for the B-17 or B-24 it was not. It had a lower gross weight than the Martin B-26.

    You could make a large twin (cut 40 feet out of a B-29 wing and two engines, shorter fuselage, 1/2 the bombbay ,etc, etc) but wither it would really do much more than the B-24 might be subject to question.

    OR you build super-twin. XB-28 on steroids but the B-17 and B-24s went around 60,000lbs gross weight. Even with better aerodynamics and fancier flaps you are not going to replace then with 40,000lb machines.
     
  6. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    "Two engine R-3350 powered bomber"
    [​IMG]
     
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  7. rank amateur

    rank amateur Member

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    Another good thread coming to an unexpected early end... ;)
     
  8. gjs238

    gjs238 Well-Known Member

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    By a post-war Maritime patrol and ASW aircraft?
     
  9. Shortround6

    Shortround6 Well-Known Member

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    #9 Shortround6, Mar 5, 2015
    Last edited: Mar 5, 2015
    First two P2V-1 prototypes and 14 production aircraft use 2300hp engines.

    One Production P2V-1 aircraft modified to P2V-2 and 80 new production planes with 2800hp engines ( water injected).

    53 P2V-3 built with 3200hp engines.

    Later versions got heavier and got either more powerful engines or turbo compounds for better economy and even later ones added underwing jet engines.

    P2V-3 went about 34,900lb empty and 64,000lbs max. had 1000sq ft of wing.

    Even running somewhat lighter performance with a pair of 2200hp engines for take-off would be???
     
  10. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    Be careful what you wish for! ;)

    The first P-2 flew in May of 45'
     
  11. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    From Wiki...

    P2V-3
    General characteristics

    Crew: 9-11
    Length: 77 ft 10 in (23.72 m)
    Wingspan: 100 ft 0 in (30.48 m)
    Height: 28 ft 4 in (8.56 m)
    Wing area: 1,000 ft² (92.9 m²)
    Empty weight: 34,875 lb (15,819 kg)
    Max. takeoff weight: 64,100 lb (29,076 kg)
    Powerplant: 2 × Wright R-3350-26W Cyclone-18 radial engine, 3,200 hp (2,386 kW) wet each
    Propellers: 3 bladed propeller, 1 per engine
    Performance

    Maximum speed: 278 kn (313 mph) (515 km/h)
    Cruise speed: 155 kn (174 mph) (286 km/h) (max)
    Range: 3,458 nmi (3,903 mi) (6,406 km)
    Armament


    Rockets: 2.75 in (70 mm) FFAR in removable wing-mounted pods
    Bombs: 8,000 lb (3,629 kg) including free-fall bombs, depth charges, and torpedoes


    P-2H (P2V-7)

    General characteristics

    Crew: 7–9
    Length: 91 ft 8 in (27.94 m)
    Wingspan: 103 ft 10 in (31.65 m)
    Height: 29 ft 4 in (8.94 m)
    Wing area: 1,000 ft² (92.9 m²)
    Empty weight: 49,935 lb (22,650 kg)
    Max. takeoff weight: 79,895 lb (35,240 kg)
    Powerplant:
    2 × Westinghouse J34-WE-34 turbojet, 3,400 lbf (15.1 kN) each
    2 × Wright R-3350-32W Cyclone Turbo-compound radial engine, 3,700 hp (2,759 kW) wet each
    Propellers: 4 bladed propeller, 1 per engine
    Performance

    Maximum speed: 316 kn (363 mp/h) (586 km/h) (all engines)
    Cruise speed: 180 kn (207 mp/h) (333 km/h) (max)
    Range: 1,912 nmi (2,157 mi) (3,540 km)
    Service ceiling: 22,400 ft (6,827 m)
    Armament


    Rockets: 2.75 in (70 mm) FFAR in removable wing-mounted pods
    Bombs: 8,000 lb (3,629 kg) including free-fall bombs, depth charges, and torpedoes
     
  12. Shortround6

    Shortround6 Well-Known Member

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    #12 Shortround6, Mar 5, 2015
    Last edited: Mar 5, 2015
    Initial design or concept work done Sept-Dec 1941 but worked stopped/severely slowed by more pressing wartime work. Work started again in the Spring (?) of 1943. Feb 19 1943 saw a letter of intent form the Navy for 2 XP2V-1 aircraft although it took until April of 1944 for the full contract. This was followed in 10 days by a contract for 15 "pilot-line" aircraft. Prototype first flies May 17, 1945.

    XP2V-1
    Crew: 8
    Length: 75 ft 4 in (23.72 m)
    Wingspan: 100 ft 0 in (30.48 m)
    Height: 28 ft 6 in (8.56 m)
    Wing area: 1,000 ft² (92.9 m²)
    Empty weight: 32,651 lb (15,819 kg)
    Loaded weight: 54,527 Lb (24,733kg)
    Max. takeoff weight: 58,000 lb (26,308 kg)
    Powerplant: 2 × Wright R-3350-8 Cyclone-8 radial engine, 2,300 hp (2,386 kW) each

    Performance

    Maximum speed: 289mph/15,600ft (465 km/h/4,755m)
    Cruise speed: 163 mph (262 km/h)
    Normal Range: 2,880 miles (4,635 km)
    Max range: 4210 miles (6,775 km)

    Armament.
    Six .50 cal guns in twin nose, dorsal and tail power mounts.
    8,000lb of bombs, torpedoes, mines.

    4563926745_873cf290c6_z.jpg
    4564557660_c75ed848bd_z.jpg

    P2V-2
    Crew: 8 (?)
    Length: 77 ft 10 in (23.72 m)
    Wingspan: 100 ft 0 in (30.48 m)
    Height: 28 ft 1 in (8.56 m)
    Wing area: 1,000 ft² (92.9 m²)
    Empty weight: 33,962 lb (15,405 kg)
    Loaded weight: 54,000 Lb (24,494kg)
    Max. takeoff weight: 63,078 lb (28,612 kg)
    Powerplant: 2 × Wright R-3350-8 Cyclone-24W radial engine, 2,800 hp (2,386 kW) wet each

    Performance

    Maximum speed: 320 mph/13,500ft (515 km/h/4,115m)
    Cruise speed: 178 mph (286 km/h)
    Normal Range: ---- miles (---- km)
    Max range: 3985 miles (6,410 km)

    Armament.
    Six 20mm cannon fixed in nose, Two .50 cal guns dorsal turret and (most aircraft) two 20mm guns in tail power mount.
    Sixteen 5in HVAR rockets or four 11.75in Tiny Tim rockets under wing
    8,000lb of bombs, torpedoes, mines in internal bay.

    6893247993_ca02b8c6c6_z.jpg

    Granted the P2V series aircraft did not use turbo-chargers.

    Information from "Lockheed Aircraft since 1913" by Rene Francillon
     
  13. Koopernic

    Koopernic Active Member

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    #13 Koopernic, Mar 5, 2015
    Last edited: Mar 5, 2015
    The main problem I see with the use of the R-3350 is that it was prioritised for the B-29. The R-3350 was critical as only the R-3350 could power a heavy bomber with enough range to bomb Japan and carry the A-bomb. Smaller engines could power an adequate medium bomber, the R-2800 being one.

    AFAIK the R-3350 entered service rated at 2200hp and this grew to 2500hp late in the war. Post war variants reached over 3500hp.

    The R-2800 started at around 1850, jumped to 2000hp and at least on the fighter versions jumped to 2200, 2600 and even 2800hp at wars end with water injection on some special models.

    The difference being that anything approaching 2000hp was a short term rating for the R-2800 but a long term rating for the R-3350. The R-3350 problems were related to full power take-offs in hot conditions when the cooling airflow over the engine and oil cooler were low whereas in most cases these extraordinary powers used on the R-2800 were combat emergency rather than take-off.

    The other problem I see is that the medium bomber concept seems to have been dropped during the war, for instance the Martin B-26 Marauder was replaced by the Douglass A-26 Invader which simultaneously replaced the A-20 Havoc (which in the MTO dropped more bombs than B-26/B-25). Medium bombers such as the Wellington, He 111, B-26 consume almost as much crew as the heavy types in return for considerably less range and bomb load.

    So an A-26 Invader with R-3350 looks impressive until you consider that in 1945 the Water injected R-2800 powered version with 2800hp could manage nearly 400mph at low altitude. Post war a 3500hp R-3350 Invader would be awesome but by then the game was in jets.

    The R-3350 was a remarkable engine in size. The R-2800 had the same or less diameter to the smaller R-2600 and the R-3350 was little bigger than the R-2800. Any airframe that could take the R-2600 or R-2800 could be adapted to the R-3350.

    What I like about a hypothetical R-3350 powered A-26 Invader is that it would be able to sustain very high cruising speeds.

    What might have been achieved though is considerable. Consider what the Luftwaffe tried with the Ju288 powered by the 2500hp Jumo 222 in early 1942.
    This was a 388mph 'heavy bomber' with 4 crew, capable of dive bombing, level bombing, multiple remote controlled turrets and carrying a very large bomb load in a copious bomb bay. The Shorter range DB610 powered version would have managed well over 408mph.

    History tells us that the Jumo 222, though able to bench 2500hp, had technical problems that prevented this level of power entering service in 1942 and was cancelled(suspended on low rate development) and despite test flights with the paired DD606/610 engines the airframe was cancelled (suspended only).

    I imagine that the Jumo 222 issues could have been fixed by derating or better fuels: the 'ignition' problems could have been overcome by using high octane C3 fuel instead of low octane B4, or the engine could have been derated by reducing boost (and thus thermal load and mechanical stress) and RPM (and thus mechanical stress) and produced a viable 2100hp engine but this was not judged worthwhile.

    The engine was scheduled for mass production (289 had been produced already for testing) in September 44 which was delayed to feb 1945 in favour of Jumo 213 production due to the allied invasion.

    At that point the Luftwaffe aren't interested in the Ju 288 anymore but are putting it in to the Ju 88 derived Ju 388 and expecting a 440mph machine. They traded 'medium' for 'fast'

    The US seems to have introduced the R-3350 at lower power levels (2200hp) too get aircraft flying and in to production in the confidence that the R-3350 would rapidly mature. As far as I can see the R-3350 doesn't offer any advantages for a medium bomber over the R-2800 till very late in the war.
     
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  14. Koopernic

    Koopernic Active Member

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    #14 Koopernic, Mar 5, 2015
    Last edited: Mar 6, 2015
    Also Martin P4M Martin Mercator, there are however jets underneath those R-3350. Rather better armed than those Neptune. The Mercator was an unsuccessful contender for a United States Navy requirement for a long-range maritime patrol bomber, with the Lockheed P2V Neptune chosen instead. It saw a limited life as a long-range electronic reconnaissance aircraft. Some saw action, one being shot down by Chinese jets.

    P4M-1_Mercator_in_flight.jpg

    Maximum speed: 410 mph (660 km/h)
    Range: 2,840 mi (4,570 km)

    Edit, just realised the Mercator was powered by the
    Pratt Whitney R-4360 Wasp Major which according to the Pratt + Whitney web site:
    First run: 1941 First flight: 1942
    R-4360 Wasp Major Engine

    The R-4360 single engine aircraft that flew before the war ended were the Goodyear F2G-1 and F2G-2 Super Corsairs (10 built, first flight July 1945. The -1 was fixed wing and the -2 was folding wing), the Republic XP-72 (2 built, first flight Feb 1944), the Martin Mauler (151 built, but no deliveries until 1947), the Kaiser-Fleetwings XBTK (5 built, first flight April 1945), The Douglas XTB2D Skypirate (2 built, first flight Mar 1945), the Curtiss XBTC (2 built, first flight Jan 1945), and the Douglas A-1 Skyraider (3,180 built, first flight Mar 1945, but no deliveries until 1946).
     
  15. syscom3

    syscom3 Pacific Historian

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    The R3350 wasnt a bad engine once the bugs were worked out.
     
  16. gjs238

    gjs238 Well-Known Member

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    Maybe it needed a fan to better cool it.
     
  17. Shortround6

    Shortround6 Well-Known Member

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    How about just a bigger opening in the cowl?

    11818176316_f1b31e6117_z.jpg
     
  18. Elmas

    Elmas Active Member

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    #18 Elmas, Mar 7, 2015
    Last edited: Mar 7, 2015
    An ASW plane, that flies most of the time practically on the deck, needs different engines and/or engine settings than a bomber or an airliner flying mostly above 20000 feet......
     
  19. Shortround6

    Shortround6 Well-Known Member

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    That is quite true.
    The original post asked if the B-17 and the B-24 could be replaced by a twin with R-3350s.
    To do that (in a strict sense) the twin would need to do those planes did. Carry 8,000lbs of bombs (at least) on short distances. 5000lbs on long distances (the old planes could hold 2700-2800 gallons of fuel without using the bomb bay) A top speed close to 300mph and a fair number of defensive guns.
    Trouble is that the wartime R-3350s were limited to 2200-2300hp (total 4400-4600) while the B-17 and B-24 had 4800-5400hp (the higher numbers in the late models), Granted the B-17/B-24 had the drag of extra engine nacelles and older airfoils/wings.

    If the old planes and new planes all use turbos then the power stays pretty much constant up to 25,000ft and beyond.

    If you want to fudge a bit and delete some of the defensive guns (waist-belly) and try for a bit more speed/range you can do that too.

    You may be able to come up with a bomber that out performs the old ones. Now is it enough improvement to change over the production lines? To fight with the B-29 for priority of engines and/or switch one of the 'satellite" factories to R-3350 production?
     
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  20. gjs238

    gjs238 Well-Known Member

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    Good summary (of the heavy bomber part of the query), thanks!

    The second part of the question concerned a higher performance medium bomber.
    There has been much discussion (on this board) of the concept of allied "schnell bombers" in the ETO and elsewhere.
    For example, we frequently discuss the use of swarms of Mosquitoes in lieu of armed heavy bombers.
    Perhaps a 2-engined R-3350 craft could fit into that discussion.
     
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