Radial engined fighters in the Battle of Britain?

Discussion in 'Aviation' started by CobberKane, Nov 12, 2013.

  1. CobberKane

    CobberKane Banned

    Joined:
    Apr 4, 2012
    Messages:
    706
    Likes Received:
    34
    Trophy Points:
    0
    In the late 1930s a British procurement specification called for an eight gun, fighter powered by an aircooled engine. The Gloster F.5/34, Vickers Venom and Martin Baker MB 2 all showed some promise but ultimately none reached production. Given that they were all powered by engines of 850 hp or less, could any of these designs have offered something given and increase in horsepower, perhaps with an engine soured from the US? Could a P&W R-1830 powered British conceivably have tangled with 109s during the Battle of Britain?
     
  2. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,760
    Likes Received:
    791
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    How much redesign do you want to do?

    A Bristol Mercury was about 1000lbs, a P W R-1830 went around 1450lbs.

    Vickers Venom;

    167655d1305712408t-frustated-projects-vickers-279-venom.jpg

    Wing area: 146 ft2 (13.56 m2)
    Gross weight: 4,156 lb (1,885 kg)
    Powerplant: 1 × Bristol Aquila AE-3S 9-cylinder sleeve valve radial, 625 hp (466 kW)

    the Aquila weighed about 830lbs.

    The Gloster F.5/34;

    gloster+f-5_34.jpg
    54f534.jpg

    Ignore caption on the last one. And note that it's first flight was two years after the Hurricane first flew.

    Wing area: 230 ft² (21.4 m²)
    Empty weight: 4,190 lb (1,900 kg)
    Loaded weight: 5,400 lb (2,449 kg)
    Powerplant: 1 × Bristol Mercury IX nine-cylinder radial engine, 840 hp (627 kW)

    MB 2;

    mb2-2.jpg
    Martin-Baker_MB_2_prototype_during_flight_trials.jpg

    Wing area: 212 ft² (19.7 m²)
    Loaded weight: 5,537 lb (2,517 kg)
    Powerplant: 1 × Napier Dagger III 24-cylinder air-cooled H-type piston engine, 1,000 hp (746 kW)

    The Dagger did weigh around 1400lbs but changing from a 23in wide engine to one of 48 in in diameter may cause a problem or two. frontal area of the twin wasp was about 2.37 times the frontal area of the Dagger.

    Pretty much the best you are going to get out of an R-1830 at the time of the BoB is 1050hp at 13,1000ft and I am a little doubtful about that. I am not sure when P&W really got the 2 speed supercharger (not two stage) in production and rated the engine for 100 octane fuel.
     
  3. JtD

    JtD Member

    Joined:
    Jan 12, 2010
    Messages:
    80
    Likes Received:
    1
    Trophy Points:
    8
    World's best radial engined fighters at the time of BoB might have been the Bloch MB150 series or the Curtiss Hawk series - both of which were competitive with a 109E or Spitfire, but fell a bit short of that performance. I doubt that contemporary British developments would have been so much better, that they had been on par or superior to the types that actually saw service.
     
  4. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,987
    Likes Received:
    432
    Trophy Points:
    83
    The 1000 HP radial married with a fixed U/C airframe is a non-starter for the BoB-era fighter, so the MB-2 is not a contender. The Gloster seem like the best proposal for a better radial, we might expect a fighter as good/bad as Re.2000 once the R-1830 is on board - so, not as good as Spit, but as good as Hurri I?
     
  5. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,760
    Likes Received:
    791
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    As good as a Hurricane I is doubtful. The Hurricanes had the 'option' of using 12lbs of boost at lower levels. the Radial engine fighter would not. Getting useful exhaust thrust from the radial is a lot harder than from the V-12.

    The Re. 2000 used a better landing gear set up than the Gloster ( at least it turned the wheels to lay flat in the wing like a P-40 rather than having having them hang out the bottom) and the Re. 2000s ( at least the early ones) didn't have self sealing fuel tanks.

    A minor question/problem with the Gloster is that it's payload (difference between tare weight and loaded) is around 200-250lbs less than the Merlin powered fighter prototypes. What wasn't it carrying? Pilot (equiped) 200lbs, eight guns and ammo radio and equipment are all going to be about the same. 200lbs (27 imp gal) less fuel?? Maybe with the Mercury engine it gave the required performance but trying to feed the R-1830?
     
  6. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,987
    Likes Received:
    432
    Trophy Points:
    83
    #6 tomo pauk, Nov 13, 2013
    Last edited: Nov 13, 2013
    The Gloster F.5/34 was supposedly good for 306 mph on 840 HP, the Twin wasp should give another 200 HP and was of smaller frontal area, so both streamlining and power/thrust are up, even without using the exhaust thrust. The additional 15 mph seem okay, and it's in the ballpark with Re.2000 and Hurri I.
    The increased boost was fine feature for the BoB fighters, unfortunately no use of it was once fighter was above 16000 ft.

    All fine, IIRC no fighters used self seasling tanks prior BoB?

    I'd like to know more about this, too.

    Another proposal - bolt the Dagger at the Gloster? Mount the ejector exhausts, too.

    added: in another forum it's posted that only 68 imp gals of fuel was aboard of the Gloster (post #14).
     
  7. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,760
    Likes Received:
    791
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    While the extra boost can't be used over 16,000ft many fights that started at over 16,000ft ended below 16,000ft. Either for catching the enemy or escaping the radial engine fighter doesn't quite have the option.

    It is certainly possible to build radial engine fighters that can 'tangle' with the 109, the trick is to build one that can 'tangle' and win or least have an acceptable loss rate.

    Few, if any did, but it is the addition of the tanks and armor that held the Performance of the BoB fighters to near the prototype levels despite increases in power of engines (extra boost, better exhausts) and better props. Any estimates of performance of late 1930s prototype fighters with new engines also have to take into account the increase in equipment (protection/electronics) that the BoB fighters used.

    Dagger peaked at about 8,000ft. Offered little more power than a Peregrine at 15,000ft. You just need a new supercharger to go with solving the cooling problems it had :)

    The Mercury offered a surprising 840hp at 14,000ft.

    The R-1830 intended for the British Beauforts, a single speed one, ( Australian ones got a different model) gave 1050 hp for take-off and 1000hp at 11,500ft. First two speed US Army R-1830 appears to be the -33 version used in the P-66 and early non-turbo charged B-24s. While prototype planes flew at teh end of 1939 with them production planes may not have shown up until the beginning of 1941.
     
  8. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,987
    Likes Received:
    432
    Trophy Points:
    83

    Agreed. It wasn't easy thing to fill Merlin's shoes (and DB-601s); in case the airframe designer got few small things wrong, one still has a performer.

    The increased weight will affect more RoC, rather than speed, since most of the improvements were under the skin. Increase of 20% of engine power was (R-1830 vs. Mercury), more than Merlin 45 vs. XII or DB-601N vs. DB-601A

    The cooling problems were not reported for the MB-2 IIRC. The Dagger was of far smaller frontal area (kinda hoped you'd state this ;) ) and it was far more conductive to a good use of exhaust thrust, as all the inlines anyway.

    So the early R-1830s would have maybe 115% of the Mercury's power at 14000 ft? It would've also offered lower frontal area.
     
  9. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,987
    Likes Received:
    432
    Trophy Points:
    83
    Some other possibilities (sorry to drift away from R-1830):
    -Bristol Pegasus 17 to 20; 885-965 HP at 15500-13000 ft; again the ability to take full advantage of the 100 oct fuel was very limited; frontal area greater than Mercury's, comparable with Wright's R-1820
    -B. Perseus X; 880 HP at 15500 ft; low take off power, no much use of better fuel
     
  10. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,760
    Likes Received:
    791
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    True on the weight but things like armor windscreens were fitted both inside and outside the existing canopy depending on plane. British also fitted IFF aerials which added drag, rear view mirrors (stretching here) Changing the type of Merlin change the weight very little (until the the two stage engine) while adding 400lbs (or more) to the Gloster is going to affect things. Larger radiators, oil coolers and/or airflow through the cowl for air cooled engines also detract from the maximum calculated speed change.

    From a test on the Hawker Hurricane "Increasing the weight from 6,316 lb. to 6,750 lb. had the effect of reducing the maximum level speed by 6 m.p.h. from 316 to 310 m.p.h. though it should be noted that the engine was changed between the two sets of results."

    Adding another 620lbs but changing to a Merlin XX engine (12 gun MK II) gets the speed up to 326mph at the same 20,000ft. Rates of climb at 20,000ft for the light Hurricane I are 1675fpm, heavy it is 1465fpm and the Mk II (12 gun) is 1740fpm.

    NOT having cooling problems with a single prototype and having epidemic cooling problems with the same engine in a twin engine bomber in attempted service use give us a conflict. Perhaps the Hereford installation was faulty but there is a difference in running one test airplane on the ground and trying to warm up and take-off multiple aircraft. English weather is one thing, trying to use the same engine/cowl in the tropics might be quite another. One tale is that Herford squadrons wouldn't even start the engines until the planes were facing into the wind. According to some sources some of the Herfords were re-engined with Pegasus engines and turned back into Hampdens.

    Yes the Dagger may offer better streamlining and better use of exhaust thrust but it is going to need all the help it can get at higher altitudes and the climb is going to be a real trade-off. Lower drag means more surplus HP but the extra 350-400lbs of engine weight is going to hurt climb. Exhaust thrust is not power, the actual power varies with the speed even if the thrust remains the same. Exhaust thrust is of much less use while climbing than if flat out level speed. A Spitfire will get more 'power' from the same exhaust thrust than a Hurricane because of the better match between the exhaust jet speed and the speed of the aircraft ( OK, not a lot better but measurable)dropping the speed from 300+ mph to under 200mph kills some of the 'power'.

    Frontal area was 14.5 sq ft for the Mercury and 12.6 sq ft for the Twin Wasp. The British cowl might have left a little something to be desired too.
     
    • Like Like x 1
  11. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,987
    Likes Received:
    432
    Trophy Points:
    83
    The 'no free lunch rule' applies here as everywhere. On the plus side we have the frontal area and power, on the down side we have more weight.
    Rear view mirror is superfluous with greenhouse canopy here. I was not claiming any spectacular speed gains anyway.

    Thanks for the data. The Hurri II had to haul another 4 guns around, with 4 casing's chutes - adds to the drag and weight, thus cuts speed.

    Seems that Herefords really were re-engined with Pegasus engines, at least I've read that several times.
    The engines in fighter were hauling less weight at higher speed, and fighters took off with less time wasted between engine starting and achieving 'cooling speed' - a better engine for a fighter than for a bomber?

    Fine points. Again, it's not easy to fill Merlin's shoes, and every engine chosen here has it's own shortcomings.
     
  12. merlin

    merlin Member

    Joined:
    Dec 27, 2006
    Messages:
    465
    Likes Received:
    0
    Trophy Points:
    16
    Occupation:
    Customer Service Manager
    Location:
    Cardiff
    To be pedantic about the thread title - there was a radial engine 'fighter' in the BoB, the Blenheim 1F !
    However, I suspect the OP is more concerned with single-engine aircraft.

    I agree with most that the Venom was a non-starter, good try but no future scope. But the Gloster f.5/34 has more potential - first in needs to fly earlier, and it needs to be able to upgrade to a better and reliable engine!! The Mercury did rise in power, but as the saying goes - 'not a lot', the Tauras would be a good fit - but reliability and altitude performance make it debatable! But who knows maybe there can be solved in time. Yet, the R-1830 also has possibilities - right size and power, but who in the UK would build it - why when!?? Though, the Gloster fighter the US engine would make a better combination for the RAAF by the time the Pacific war erupts.

    Yet, the is the designs for the Whirlwind spec to consider, the Bristol 153, and Boulton-Paul P.88a were both design to take the Hercules. The P.88a was the more favoured of the two, and it's not impossible with an earlier need for altitude, the modifications are made earlier, and just to make it easier - no Stirling so less engine 'demand' - granted the mods. aren't easy but it's possible.

    Other radial options - Martlet ordered by FAA, rather than taking over the French order, so ready operationally earlier and FAA makes contribution to the battle not with pilots, but with squadrons - aircraft + pilots vectored into the battle by RAF controllers.
    Worse scenario - RAF forced to use P-36s, due to damage to fighter factories!
     
Loading...

Share This Page