SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
That's a pretty cool airplane.
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One of the differences between a V-1710 or V-1650 and a radial like the R-2800, are the main bearings.
In the inline engines, the crank is "floating" between the bearings by means of hydraulic pressure. Once damage has occurred to the engine, resulting in loss of oil pressure, the crankshaft starts grinding on the bearings and engine seizure is soon to follow.
In the radial, the main bearings were roller bearings that relied on a "wash" to keep them lubricated, so a loss of oil pressure did not result in the same failure as the above-mentioned.
Add to this, that the radial was not dependant on liquid coolant to operate, so damage that resulted in loss of it's oil would not cause immediate failure.
I think it is a bit of a stretch to say they were developed for the Wyvern. The Wyvern was seen as one potential use for them but its Spec was originally written around a piston engine.Indeed, for the Westland Wyvern.
You mean the Gloster Trent-Meteor? Gloster Trent-Meteor - experimental aircraftThe Brits were working on a turbo prop engine during WW2.
Part of the start up procedure of the R2800 is to turn the engine over to drain the oil from the bottom cylinders and pre oil the main bearings so they aren't scuffed.The R-2800 didn't have roller main bearings or big end bearings.
IIRC the sparkplugs are removed from the bottom cylinders and then the prop is pulled through by hand several revolutions, especially if the aircraft was sitting for awhile.Part of the start up procedure of the R2800 is to turn the engine over to drain the oil from the bottom cylinders and pre oil the main bearings so they aren't scuffed.
Is this true of all radials?.IIRC the sparkplugs are removed from the bottom cylinders and then the prop is pulled through by hand several revolutions, especially if the aircraft was sitting for awhile.
All? IDK, Most? I would say yes...Is this true of all radials?.
One of the differences between a V-1710 or V-1650 and a radial like the R-2800, are the main bearings.
In the inline engines, the crank is "floating" between the bearings by means of hydraulic pressure. Once damage has occurred to the engine, resulting in loss of oil pressure, the crankshaft starts grinding on the bearings and engine seizure is soon to follow.
In the radial, the main bearings were roller bearings that relied on a "wash" to keep them lubricated, so a loss of oil pressure did not result in the same failure as the above-mentioned.
Add to this, that the radial was not dependant on liquid coolant to operate, so damage that resulted in loss of it's oil would not cause immediate failure.
This is not to say that it would run indefinitely in the event of critical damage, but it would far outlast an inline that suffered comparable damage.
Sadly (or not... I`m not sure sometimes) I missed proceedings by three quarters of a century. But I was told by the son of one Battle of Britain pilot (would have to go look up the squadron, but Lionel Goddard was the pilots name), that many in his squadron (which did unusually well) had a load of engine mechanics who had been motorcycle racing people in peacetime. He claims that they did lots of little bits on their pilots Merlins, like cutting the valve seats into three angles instead of one, and so on.
However, this is not something I`m in any position to prove.
No horsepower for one thing (everyone was making more than us ) for another very bad high attiude performence critcal was only 17k feet i would much rather have had these specs
Performance
- Powerplant: 1 × Napier Sabre IIB H-24 liquid-cooled sleeve-valve piston engine, 2,420 hp (1,800 kW) at + 11 lb boost for 5 minutes at sea level[nb 15] ; 2,010 hp (1,500 kW) for take-off ; 2,045 hp (1,525 kW) at 13,750 ft (4,190 m)[v 5]
- Propellers: 4-bladed de Havilland Hydromatic, 14 ft (4.3 m) diameter constant-speed propeller[v 6]
In the mk1 mustang
- Maximum speed: 435 mph (700 km/h, 378 kn) at 17,000 ft (5,200 m) ; 390 mph (340 kn; 630 km/h) at sea level[v 7]
- Combat range: 420 mi (680 km, 360 nmi) [v 8]
- Service ceiling: 36,500 ft (11,100 m)
- Rate of climb: 4,700 ft/min (24 m/s)
- Time to altitude: 20,000 ft (6,100 m) in 6 minutes at combat power[v 9]
2200HP means being able to carry better armerment too instead of 6x.50cal you could 8 or 6 and 2 20mms and with the A-36 being used as a bomber it would be capable of carrying a better bomb load than a allison engine version
One of the reasons for the low reliability of the Merlins in Spitfires/Hurricanes etc was that the carb intake was on the bottom of the engine so that it sucked in all the dirt and shit thrown up by the propellor while all the large American engines of the time had the intake at the top of the engine where they got clean air. North American at least had the sense from day 1 of its Merlin design to move the intake as far forward as possible to massively reduce that problem.
And where did the Sabre have its carb intake - on the bottom of course.
It is a bit more complicated than that.The only reason it had crap high altitude performance was that the USAAF refused to allow Allison to produce a two speed supercharger version or to fit an integral two stage supercharger and insisted that adding a turbocharger was the answer to everything.
Maybe a better choice would have been... a two stage Allison V-1710.When we designed the mustang was there a better choice than a V-1710 ? I'm talking P-51A and A-36 time period...
I always thought the reason for the P-51 intake was that a Spit or Hurricane style intake would disturb the airflow going into the radiator, but this sounds like another nice feature of it.
The P-51 intake was as far forward and as high above the ground as possible because the designers thought right from day one of the Merlin conversion - how do we have a single unit that works in all operational environments without any drag penalties. Having it as high and far forward as possible kept out the debris thrown up by the prop and allowed the installation of an effective air intake filter system which further protected the engine from FOD.
Allison was so crap that Rolls Royce fixed its Merlin/Griffin bearing issues by making Allison bearings under licence.
Rolls-Royce were making Allison type bearings under licence years before the Griffon (why do people persist spelling it Griffin, like a a character from a cartoon?), possibly from around the time of the PV12's initial development in the early 1930s.