Another interesting angle on the radial turbocharging topic is the R-3350 radial used in the Lockheeed Constellation. It was known as a turbo-compound engine in that the three exhaust drived turbine wheels captured and then directed back to the engine power that would have normally been lost in the exhaust. Each turbine wheel had a chutch mechanism that coupled it to the crankshaft. Each turbine recovered approximately 500HP if I remember correctly.
Warbirds with turbocharged engines.
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I've always thought that would be a great way to do a hybrid vehicle .
Have the PRT spin a generator and return exhaust energy to the battery, motor driving the rear wheels. AWD for max- effort takeoffs, energy recovery at all times.
Have the PRT spin a generator and return exhaust energy to the battery, motor driving the rear wheels. AWD for max- effort takeoffs, energy recovery at all times.
Speaking of R-3350s, I was in the pits at the Reno Air Races a number of years ago. Rare Bear was outside of the hanger and they were doing full power run ups. The cowl was off and one of the crew was standing in front of the engine with an automotive timing light pointed at the hub(Much braver man than I).
When they were done I asked what they were doing. He said they were measuring horsepower by calculating it from the degrees of crank twist.
Right at 4000 he said with a smile.
Ed
When they were done I asked what they were doing. He said they were measuring horsepower by calculating it from the degrees of crank twist.
Ed
Also speaking of R3350s. Along with 2 J34 turbo jets, the P2V Neptunes I flew in in the mid 60s had 2 R3350s with 3 turbos per engine. No, the turbos will not help in extreme altitudes(our max was maybe 18000 ft) however the turbos did give us a boost at low levels(we often flew under 500 ft on patrol). Also we used straight 80 wt oil in the 3350s and a thin synthetic turbine oil in the J 34s.
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Packard was selected for US production of the V-12 Merlin. Some say it was because packard brought the first V-12 automobile to market in 1916, but more likely, it was the engineering excellence of Packard. In 1932, Packard design engineers could measure surfaces to a tolerance of one millionth of an inch (according to Packard literature of the time...ask me how I know...)
Some tweaks by Packard are what made the engine so great in the Mustang...from Wikipedia:
The first American version of the Merlin was the Packard Merlin 28 (Mark XX), designated the V-1650-1 by the American military. This engine used a single stage, two speed supercharger. As the Merlin 28, it was used for the Avro Lancaster bomber. The USAAF V-1650-1 version of this engine was used in the P-40Fs. The initial Packard modifications were done on this engine by changing the main crankshaft bearings from a copper lead alloy to a silver lead combination and featured indium plating. This had been developed by General Motors' Pontiac Division to prevent corrosion which was possible with lubricating oils that were used at that time. The bearing coating also improved break-in and load-carrying ability of the surface.
The real improvement Packard incorporated into the Merlin was adopting the Wright supercharger drive quill.[citation needed] This modification was designated the V-1650-3 and became known as the "high altitude" Merlin destined for the P-51. The two speed, two stage supercharger section of the -3 featured two separate impellers on the same shaft which were normally driven through a gear train at a ratio of 6.391:1. A hydraulic gear change arrangement of oil operated clutches could be engaged by an electric solenoid to increase this ratio to 8.095:1 in high speed blower position.
Some tweaks by Packard are what made the engine so great in the Mustang...from Wikipedia:
The first American version of the Merlin was the Packard Merlin 28 (Mark XX), designated the V-1650-1 by the American military. This engine used a single stage, two speed supercharger. As the Merlin 28, it was used for the Avro Lancaster bomber. The USAAF V-1650-1 version of this engine was used in the P-40Fs. The initial Packard modifications were done on this engine by changing the main crankshaft bearings from a copper lead alloy to a silver lead combination and featured indium plating. This had been developed by General Motors' Pontiac Division to prevent corrosion which was possible with lubricating oils that were used at that time. The bearing coating also improved break-in and load-carrying ability of the surface.
The real improvement Packard incorporated into the Merlin was adopting the Wright supercharger drive quill.[citation needed] This modification was designated the V-1650-3 and became known as the "high altitude" Merlin destined for the P-51. The two speed, two stage supercharger section of the -3 featured two separate impellers on the same shaft which were normally driven through a gear train at a ratio of 6.391:1. A hydraulic gear change arrangement of oil operated clutches could be engaged by an electric solenoid to increase this ratio to 8.095:1 in high speed blower position.
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The idea of turbo-compounding the R-3350 was to reduce fuel consumption during cruise, to extend the range of the aircraft. Added benefit was about 1000 HP more power was available at takeoff. The power recovery turbines used a fluid coupling and coupled their recovered power back into the crankshaft. These were also velocity or "blow down" turbines, not pressure turbines. The added exhaust restriction was minimal. These engines had also single stage two speed superchargers.
The aircraft with the turbo compounded engines were the first ones capable of crossing the Atlantic non-stop in the west-bound direction.
The Connies still flying today have the high speed gear selection of their superchargers disabled, because the 115/145 avgas is no longer available, and 100LL does not have high enough octane to prevent engine damage from running high blower. In connies, the only time the cabin superchargers (pressurization) worked was when the engines had been shifted to high blower, since high blower is no longer happening, the aircraft are limited to about 10,000 feet altitude.
Hollywood rented the Kansas city connie for that film The Aviator about Howard Hughes, to fly it from KC to Burbank, they had to go the long way around the rockies because they can't fly over them any more.
The aircraft with the turbo compounded engines were the first ones capable of crossing the Atlantic non-stop in the west-bound direction.
The Connies still flying today have the high speed gear selection of their superchargers disabled, because the 115/145 avgas is no longer available, and 100LL does not have high enough octane to prevent engine damage from running high blower. In connies, the only time the cabin superchargers (pressurization) worked was when the engines had been shifted to high blower, since high blower is no longer happening, the aircraft are limited to about 10,000 feet altitude.
Hollywood rented the Kansas city connie for that film The Aviator about Howard Hughes, to fly it from KC to Burbank, they had to go the long way around the rockies because they can't fly over them any more.
re blowdown and "pressure" turbines...
Turbine designs have two different "familes", impulse and reaction.
In an impulse turbine (think a pelton wheel, or a cup taped to the rim of a wheel, and a hose throwing water into it), the pressure of the fluid exiting the cup is pretty much the same as the pressure of the water hitting it, it's just changed direction, hopefully 180 degrees, and simply falls to the ground...that's impulse...however, there IS a pressure drop across the turning vanes that get it at the right entry angle.
Other type is reaction, which sort of has the blade "flying" through the moving gas, maybe a surfboard analogy works, where there is a pressure drop across the rotating blades, but little across the stationary ones that turn the gasses back.
either system, and the mixes that invariably exist between them have a pressure drop of some measure.
Turbine designs have two different "familes", impulse and reaction.
In an impulse turbine (think a pelton wheel, or a cup taped to the rim of a wheel, and a hose throwing water into it), the pressure of the fluid exiting the cup is pretty much the same as the pressure of the water hitting it, it's just changed direction, hopefully 180 degrees, and simply falls to the ground...that's impulse...however, there IS a pressure drop across the turning vanes that get it at the right entry angle.
Other type is reaction, which sort of has the blade "flying" through the moving gas, maybe a surfboard analogy works, where there is a pressure drop across the rotating blades, but little across the stationary ones that turn the gasses back.
either system, and the mixes that invariably exist between them have a pressure drop of some measure.
Didn't Detroit Diesel sell a turbo-compound OTR diesel engine not that long ago?
found it...http://www.detroitdiesel.com/engines/dd15/specs.aspx
found it...http://www.detroitdiesel.com/engines/dd15/specs.aspx
Yup... BMW has the electrically - assisted turbo ,so why not let it spin the other way?
Originally Posted By: needsducktape
This era is absolutely fascinating to me,
my grandfather was a engineer during that time period-
Its amazing how brilliant these machines were AND designed without computers or other modern technology.
It definitely took brilliant men.
This era is absolutely fascinating to me,
my grandfather was a engineer during that time period-
Its amazing how brilliant these machines were AND designed without computers or other modern technology.
It definitely took brilliant men.
I was just thinking about that. It seems our (U.S.) most productive years, let's say WWII though the 60's, were without the aid of computers, cell phones, or FedEx.
Ed
Ed
Take a peek at:
http://www.allpar.com/history/military/b-29.html
http://www.allpar.com/history/military/b-29.html
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