DB 610 Fuel Consumption

[SpicyJuan11]

Does anyone know how much fuel the 606/610 guzzled? Was it particularly worse than the 601/605? I am trying to understand why the He 177 seems to have a very short range and my suspicion is the extraordinary weight and high fuel consumption of the engines. However I can't find anything online to confirm the latter

 

[tomo pauk]

I am trying to understand why the He 177 seems to have a very short range and my suspicion is the extraordinary weight and high fuel consumption of the engines.

What range figures are in play here?

 

[SpicyJuan11]

What range figures are in play here?

I'm trying to figure out if the He 177 had "average" or really poor payload over range. From the data sheets and manuals I've come across it seems that the Manchester/Lancaster blow the 177 out of the water, but in turn appears better than the B-17G, B-24, and Halifax. I'm not sure why the 177's range is so short despite having a much higher cruise speed. Knowing thr 610's fuel consumption could help prove or disprove my suspicions

 

[tomo pauk]

I'm trying to figure out if the He 177 had "average" or really poor payload over range.

What are the fuel tankages for the respective cases?

 

[tomo pauk]

Does anyone know how much fuel the 606/610 guzzled? Was it particularly worse than the 601/605?

Max specific consumption of the DB 606 at the rated height (4.9 km, no ram) was 235 g/PSh. Minimal - 205 g/PSh.
Same as what the DB 601E had, basically (no wonders here).

 

[GregP]

DB 601: Specific Fuel Consumption: .492 lb / hp-hr at max continuous. 1.159 hp TO; 986 hp @ 2,400 rpm, 13,100 ft max continuous.

DB 605 Specific Fuel Consumption: .474 lb /hp-hr at sea level max cruise. 1,775 hp; 2,800 rpm, MW-50 injection TO; 1,065 hp, 2,300 rpm, 18,000 ft max continuous.

WWII avgas was about 6.25 lb per gallon at STP. So, assuming max continuous power for each, we get 77.7 US gal/hr for a DB 601 and 80.8 US gal/he for a DB 605, both at max continuous with fuel at 6.25 lbs/ US gal.

A DB 606 ws a double DB 601 and a DB 610 was a double DB 605.

So, I'd estimate fuel consumption at max continuous power to be:

DB606: 155.4 US Gal/hr, or 588.2 litres/hour.

DB610: 161.5 US gal/hr, or 611.4 litres/hour.

Both real-world values might be very slightly higher due to having to operate the intermeshing gears between the Vee banks.

 

[Supercharged]

DB 610 Handbook says:

960 litres/hour @ take off & WEP @ ground level
800 litres/hour @ climb & combat @ ground level
640 litres/hour @ max. continue @ ground level

880 litres/hour @ WEP @ 18700ft
760 litres/hour @ climb & combat @ 19028ft
640 litres/hour @ max. continue @ 18044ft
510 litres/hour @ max. economic cruise @ 18700ft

take off & WEP = 2800RPM@1,42ATA
climb&combat = 2600RPM@1,30ATA
max. continue = 2300RPM@1,15ATA
max. economic cruise = 2100RPM@1,00ATA

 

[GregP]

Well, 161.5 US Gal/hr converts to 611.3 liters/hour.

If you add a bit for the intermeshing gear friction, I'm not surprised at the 640 number.

 

[Denniss]

The base engine of the DB 610 may have used the same engine block as the 605 but there were differences like a completely different firing order of the cylinders so at least the crankshaft was different. That may have influenced power characteristics and fuel efficiency. Plus the starboard engine of the "pack" had been JuMo'ed with the supercharger being on the starboard side of the engine too.
Both engines of the 610 had the same firing order, the port engine's firing order was offset by 30 degrees from the starboard engine.

 

[GregP]

The base engine of the DB 610 may have used the same engine block as the 605 but there were differences like a completely different firing order of the cylinders so at least the crankshaft was different. That may have influenced power characteristics and fuel efficiency. Plus the starboard engine of the "pack" had been JuMo'ed with the supercharger being on the starboard side of the engine too.
Both engines of the 610 had the same firing order, the port engine's firing order was offset by 30 degrees from the starboard engine.

Interesting, Denniss.

That wasn't the case for the Allison V-3420. Both of the Vee banks ran like a regular V-1710.

 

[Denniss]

Was probably easier to mate to V-1710 than two DB-605ish engines. It seems the supercharger on the allison was in the rear of the engine + they could mate a left and right turning engine into a V-3420

 

[Engineman]

The DB 610 engines did have considerable problems in development. Some of the problems were involved with vibration and resonance. The firing order was changed to suit the needs of the engines in the coupled version. Interestingly, the firing order was changed with the same crankshaft. This was possible because it is possible to swop the phases of two of the three planes in a three plane crank of a V12 4-stroke. So, the 1,8,5,10,3,7,6,11,2,9,4,12 firing of a standard DB 605 was changed to 1,11,2,9,4,7,6,8,5,10,3,12 order of a DB 610, the cylinders being numbered 1 to 6 on the right bank from the front and 7 to 12 on the left bank from the front. You can see that the 1,7,6 and 12 maintain their order but, the 8,5,10,3 and 11,2,9,4 groups swop their firing positions and so exchange their firing stroke for their inlet stroke. To do this, the camshafts, the magneto wiring harness and the fuel injection pump plumbing was all changed to suit the different arrangement. Of course, there were effects on the intake air flow distribution but, these must have been acceptable. Interestingly, the timing of the firing is offset at 30 degrees between the two engine components of the double engine, which means that firing impulses to the reduction gear are evened-out at every 30 degrees.
When the He 177 program was scrapped, many spare DB 610 engines were split to use the LH "X" component engine as a DB 605 A. These engines retained the 610 firing order and components and had a large stenciled Red paint warning to groundcrew about their 610 firing order etc.

Eng