Thumpalumpacus
Major
How might that affect the hypothetical jet-engined performance? What's the weight of the fuel? Pumps? Plumbing? Reinforcement for such a large tank?
Aerodynamics might be another issue, too.
Jet Lancaster range?
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How might that affect the hypothetical jet-engined performance? What's the weight of the fuel? Pumps? Plumbing? Reinforcement for such a large tank?
Aerodynamics might be another issue, too.
wuzak
Captain
It depends if the fuel specified above is the amount with a 12,000lb bomb load or the full capacity of the fuel tanks.
It could also be additional bombs, or other equipment.
The modifications would be mainly around the wing - new engine mounts, new nacelles, mods to the flaps and ailerons, mods to the leading edge. May need mods to the undercarriage.
Remove turrets and plate over - they was done for other Lancaster projects as well.
A clean sheet would give better performance, but likely take years longer to get to the front line.
Thumpalumpacus
Major
I'd imagine that reconfiguring a Lancaster to a jet-bomber before 1945 is probably going to be a little slow, too.
You can have quick, affordable, or quality. Pick two.
Yup, the age-old maxim in aviation. Fast, cheap good. If you want good and fast, it won't be cheap, if you want good and cheap, it won't be fast, if you want fast and cheap, it won't be good.
wuzak
Captain
It depends on when the program is started.
If the program was evolved at the same time as the Derwent I, it may have been possible to have a few by 1945.
But, it depends on the availability of engines and airframes. Lancasters were in huge demand, so that would limit supply as well.
Also, the Air Ministry weren't too keen of having jet engined aircraft in combat over enemy airspace, so having a big bomber with 4 of them cruising at speeds that the enemy could comfortably achieve with piston fighters would not have appealed to them.
My point is that a jet Lancaster would be possible, though probably very late in the war.
It could have been made relatively affordably, and reasonably quickly, though in small numbers.
wuzak
Captain
Just to put my calculations down for comparison.
2,150 ImpG x 7.39lb/ImpG = 15,888lb
25% reserve means 75% available => 15,888lb * 0.75 = 11,916lb.
Fuel consumption = 1,550lbf * 1.17lb/lbf/hr = 1813.5lb/hr
Endurance = 11,916lb / (1813.5lb/hr) = 6.5 hours.
So the range depends on what speed the aircraft could cruise at.
200mph * 6.5 hours = 1,300 miles
250mph * 6.5 hours = 1,625 miles
300mph * 6.5 hours = 1,950 miles
Those saddle tanks held 1,200 imperial gallons. Apparently the crews weren't very happy at the idea of all that petrol above their heads! So the idea was dropped.
After briefly considering air to air refuelling, Tiger Force Lancs, or at least some of them, were due to get a 400 imp gal tank in the aft bomb bay.
MiTasol
1st Lieutenant
Meteor 3 had 325 gal internal and could carry some external fuel but I do not know what the earlier versions carried. Probably the same as there were two fuselage tanks so additional fuel would need a significant redesign unless they filled random holes like they did on the Spitfire.
buffnut453
Captain
Nice to know that my concerns about the design were expressed by the crews at the time. It's "smug mode" time!
View: https://www.youtube.com/watch?v=duLzswQsUJM
ThomasP
Senior Master Sergeant
re the weight of RAF jet fuel in 1943-45
The Pilot's Notes for the Derwent Mk I gives the fuel used as a blend of Aviation Kerosene (RDE/F/KER/210) and lubricating oil (DED.2472 B/O) in a ratio of 9:1.
The density of RDE/F/KER/210 fuel is listed as .769 and lubricating oil to DED.2472 spec as .90, so the weight of a gallon of jet fuel would be ~6.52 lb/USgal or 7.82 lb/UKgal.
The Pilot's Notes for the Derwent Mk I gives the fuel used as a blend of Aviation Kerosene (RDE/F/KER/210) and lubricating oil (DED.2472 B/O) in a ratio of 9:1.
The density of RDE/F/KER/210 fuel is listed as .769 and lubricating oil to DED.2472 spec as .90, so the weight of a gallon of jet fuel would be ~6.52 lb/USgal or 7.82 lb/UKgal.
don4331
Senior Airman
Each Derwent produces 1,550lbf/burns 1813.5 lbs/hr. Multiply fuel burn by 4 for our hypothetical jet Lancaster - you've got <2hrs fuel.
As noted, that is static/sea level. Junkers Jumo 004 made ~60% sea level power at 36k' but 25% more power at 560mph than at 275mph. So, SWAG says Hooker's hypothetical Lancaster would have ~75% sea level cruise power at his planned 30k' cruising altitude. I've assumed that power was good for the 400mph, again quoted from Hooker.
And yes, I mistook US and Imperial gallons, realized the right after I posted, but it was what it was, so range could be increase ~20% for the difference in size of gallons but reduced by the heavier weight on kerosene - you're still not getting to Berlin
I didn't plan any extra fuel - no tanks for it without impacting bombload.
I think the biggest initial issue for the jet Lancaster - there is no airflow over the tail surfaces for take off ala the tail dragger Me.262. Accelerating Lancaster down runway, then slamming brakes to flip tail up like Galland did with the Messerschmitt jet while sitting on >25k lbs of fuel and bombload would be a little too exciting for me. 4 jet engine B-24 would be much safer to take off in.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
How would only four jet engines be able to make the Lancaster even somewhat functional?
The early jet engines simply did not have the thrust to heft such a large aircraft into the sky, let alone move it at any reasonable speed with a full bomb load.
The Lanc would need at least six to be somewhat effective and as I mentioned earlier, even the Ju287 only managed 357 mph at 27,000 feet with four Jumo004B engines.
The early jet engines simply did not have the thrust to heft such a large aircraft into the sky, let alone move it at any reasonable speed with a full bomb load.
The Lanc would need at least six to be somewhat effective and as I mentioned earlier, even the Ju287 only managed 357 mph at 27,000 feet with four Jumo004B engines.
wuzak
Captain
Elvis
Chief Master Sergeant
On top of that, JP4 is approx. 1/2 lb./gallon heavier than Av Gas, so you need to factor that in, as well.
MiTasol
1st Lieutenant
The other factor is that jet engine fuel consumption is inversely related to altitude.
Here is the chart from a two seat aircraft powered by an uprated Nene engine. Note that operating at 10,000 metres gives an almost 50% increase in range over operating at 5,000 metres so operating the jet lanc at 33,000 ft would give a massive range improvement over operating at 16,000 and they normally operated high anyway,
Here is the chart from a two seat aircraft powered by an uprated Nene engine. Note that operating at 10,000 metres gives an almost 50% increase in range over operating at 5,000 metres so operating the jet lanc at 33,000 ft would give a massive range improvement over operating at 16,000 and they normally operated high anyway,
Thumpalumpacus
Major
Admiral Beez
Major
Elvis
Chief Master Sergeant
Is that why the B-36 used a combination of propellor and jet engines?
My dad was in the USAF during those years and he said that B-36 pilots would often cut the prop engines and coast on the jets alone, once they reached altitude.
It was a fuel saving strategy.
MiTasol
1st Lieutenant
That manual does not show that data but the internal fuel capacity is 1080 L so you can work back to it if you wish.
Other information supplied is below - note table 9 says 1102 litres internal but other references are 1080 L. 22 litres is probably not significant and it may be because the aircraft sits at a slightly different angle without the drop tanks.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Won't cut it, not at that point in time.
The Ju287 required four jet engines and it was one third the weight of a Lancaster.
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