You confuse strategic demands with aerodynamic potential?
Stewart,There are many reasons why there were <800 Lancs available at any one time. They were built, used and destroyed at such a rate that less than 800 were available at any given time during the war.
You're missing my point. When comparing tonnage, you've been talking total bombs dropped by the B17 as a type. The only way to get a true comparison would be to put equal numbers of each aircraft side by side and compare them.
From your post. They were less reliable than the B-17 and had a much lower mission readiness rate than the B-17.
Prove it? In terms of single aircraft, they often flew on far longer - look at numbers of aircraft that got over 50 missions. Or over 100.
I've tried to do this several different ways and each time you change the subject or twist the point, but here goes again from the top;
The B-17 carried on average, less bomb tonnage per mission as reflected in the total tonnage divided by the number of missions flown! IIRC, about 4,000 pounds for the B-17 force Vs 7,800 pounds for the lancaster force total.
The Lancaster force required almost 8000 planes and one or two years longer to do this. There were never that many B-17s in England!
Of the ~7,000 B-17s sent to England, almost a thousand less than the total production of Lancs, they flew for about a year less. SO, less B-17 planes flew MORE missions than Lancaster planes in fewer years and dropped more tonnes of bombs. They were able to do that because the Engines were much more reliable than the Merlins in the Lanc.
The bomb loads and distances were determined by strategy and tactics, not the various planes ability to carry bombs over range! That has absolutely nothing to do with it.
The typical bombing altitude of American missions varied between 25,000' and 31,000'! Some at almost 35,000'. No mission was ever scheduled to operate at less than 25,000' over the target. This was the minimum altitude considered necessary to avoid the most dangerous Flack. Most Lanc missions were under 17,000' over the target, NONE were at altitudes over 25,000'! Just curious; What was the maximum number of B-17s sent on any single day against the Nazis?
Unfortunately they didn't avoid the flak or the fighters. Reading 91st BG, 303rd BG and various other 8th AF records show bombing heights of around 23,000 ft. None below 25,000 eh? Read on.
There is a differance between schedualed and actual, but that does not change the fact that the 8th AAF flew more missions in less time or that their consistant average altitude was higher!
The most B17's I can find on one mission was 453 B17's to Cologne in October 1944.
You missed the schwinfurt raid with ~660 bombers, IIRC.
I've pointed out to you twice now - bombing height and ceiling aren't the same. I've found a couple of reference to B17's in the Pacific bombing from 30,000 ft, but no details of the load.
To answer your question though; lifting 22,000lbs to 16,000 ft is related to the B17's attempts to get 17,600lbs to the same height, for substantially less range.
Any planes ability to carry load is inversely proportional to the range, ceiling and speed at which it does it.
Flying higher requires more throttle. That shortens range. That lowers bomb load that can be carried. Because air rarifies at a constant manner as one ascends, the difference in weight can be used to calculate the exact ceiling that a plane can reach with any given load, IF you know the ceiling with some other load. Do those calcs!
You've only got to look at the Lanc to realise its not the most aerodynamic aircraft in the world. Its wing isn't designed for speed either, its there to lift a heavy weight at low speed... something it did quite well into the 1990's.
Except that they were fitted with the much more powerful version of the Merlin engine! Most Lancs did not use this engine! In my book that made them "Special"! Could that mission have been flown with the much less powerful type XX Merlin engine? Not on your life!
Apart from the very first batch of Lancasters there were few that had Merlin XX engines... about 900 aircraft out of 7,377. I posted this further back in the thread, this highlights your ignorance. The NFxxx batch were STANDARD BIII AIRCRAFT. "Special" aircraft were designated as such.
I can see that we are useing the same word for different meanings. According to Janes, page 106, PP 5; The Lancaster B Mk-III was the same plane as the B Mk-I except it was fitted with Packard built Merlin 28s, which were exactly the same as RR built Merlin XXs! 1280 HP! As far as I can see, all other Merlin engined Lancs were "Modified" as in "Special"! out of the ~8000 built, less than 100 had any Merlin engine that made over 1400 HP and they were probably all out of the B Mk-I batch.
Still waiting for you to list how many Lancs were built/retro-fitted with the RR made Merlins, Vs how many were made with American made Packard Merlins? Note that WO the exact numbers in front of me, every book I have, stated that MOST Lancs were built with Packard built Merlin engines, not RRs. Every last one of those was the American Version of the Merlin XX.
Indeed, and you'll notice that Packard never built the Merlin XX, they produced the Merlin 28 which was based on it, and re-engineered. In regards of numbers around 3,030 Packard equipped Lancaster BIII were built, out of 7,377.
Exactly my point! The vast majority of Lancs, >7,000, had SINGLE STAGE ENGINES! Also according to Janes, on the same page; The Maximum bomb load at 1,000 miles range was 14,000 pounds! Just to clarify that point; If you used 100% of the fuel to fly the mission, WO leaving any reserve, it could fly 500 miles, drop the bombs and return, but only if you did not use any fuel forming up or waiting to land. That means that in practical terms, you could send them 400-450 miles at the most, if they did not form up into groups.
Along those lines, except for the 33 "Specials", the maximum bomb load for the rest of the >7,000 Lancasters was 14,000 pounds! The vast majority >8,000 B-17s could carry 17,600 pounds of bombs. ( Winner= B-17)
I posted the Lancasters loads, yet you've ignored them. I also posted the woeful performance of the B17 when given 17,600lbs to carry.
I forgot the load list you posted because it was not relevant at that point. Since that time, I have found that less than 40% could carry the heavier, 18,000 pound load. B Mk-IIIs only! Of course discounting all 387 with engines of more than 1,280 HP, including 300 B Mk-IIs. (I have yet to find the maximum standard bomb load of the B Mk-II!)
Again from Janes; on page 210, B-17 Range with maximum bomb load at 220 MPH = 1,100 miles, or about 100 miles farther than the Lancaster with 3,600 pounds less bombs. So much for the differance in L/D!
Admittedly the Lancaster regularly carried 14,000lbs. What did the B17 carry on a regular basis?8,000lbs. Winner = Lanc. Much less! about 4,500 pounds on average! The average of all Lancaster missions was about 7,800 pounds. Effects of lower operating altitude and shorter operational range AS DICTATED BY THEIR RESPECTIVE MASTERS!! HAVING ABSOLUTELY NOTHING TO DO WITH AIRCRAFT PERFORMANCE!
Just keep it to a representative number. For example - If I had one aircraft and you had two, and we both sent them out against the same targets at the same time; you'd drop more. If we take one aircraft of mine, and one of yours, it becomes more representative between aircraft rather than operator.
So on to the analysis;
1. The EEW of the B-17 is slightly less than the Lancaster's Empty Equipped Weight!
2. Both aircraft have the same MTO, or Maximum Take Off weight about 65,000 pounds.
3. The BEST B-17 has less available power than any Lancaster variant! ( 1,200 to 1,280!)
4. Depending on model, altitude, weight, etc, the B-17 is between 13 and 30 MPH faster than the Lancaster! ( Any Lancaster!)
5. Therefore, it has a better L/D and is more efficient aerodynamically.
6. I could go on about fuel tankage and SFC, but that would be superfluous.
If the Lancaster was made with Packard engines, IE, a B Mk-III it could carry 18,000 pounds to a range of <800 miles. That is a heavier bomb load than any B-17 could do, but the drawbacks were, less range, mixed larger and smaller bombs, lower altitude, depending on model, 16,000 to 19,500' and with less speed. On the B-17s side it could drop four identical 4,000 pounders, carried internally, with actual weights about 3,850 pounds to a range od 1,250 miles and an altitude of 26,500'.
Find me an available jet that could do the job the Lancaster was doing in Canada in the 1960's, or in the Pacific. This is relevant how?
Wrong assessment! The minimum bombing altitude over Europe was 25,000'!
No, I think you need to go read some more. Here's a part of an article by John T Correll, for Airforce magazine.
"Postwar analysis found that accuracy had been about the same in Europe and Asia for day visual and radar precision bombing. Eighth Air Force in Great Britain put 31.8 percent of its bombs within 1,000 feet of the aim point from an average altitude of 21,000 feet. Fifteenth Air Force in Italy averaged 30.78 percent of its bombs within 1,000 feet from 20,500 feet. In the Asia and the Pacific, Twentieth Air Force—45.5 percent of whose sorties were daylight precision despite the emphasis on area bombing in the last months of the war—put 31 percent of its bombs within 1,000 feet of the aim point, although the bombing altitudes were on average 4,500 feet lower than for Eighth Air Force"
Note he says 'average' not 'minimum'
I have not seen this article! Taking it at face value American bombing altitudes were lower than most other authors have written. But how does that lower altitude stack up Vs the well under 20,000' or barely over 15,000' for most Lancaster missions?
Summing up?
B17 =
Faster at higher altitude. Comes at the cost of range and payload. Daylight missions required nearly 4,000lbs of payload capacity used by defensive armament, which though substantial is barely adequate.
1. The EEW of the B-17(any), INCLUDING the 4,000 pounds of armor, ammunition and weapons was about 1,000 pounds less than the EEW of the Lancaster. Different more advanced construction techniques. Really bad point since the B-17 was started ~half a dozen years before the Lanc? I think, my personal oppinion that is, is that the differance in weight was caused by the added metal required to strengthen the 33' long bomb bay which protruded long beyond the wing spar(S) which supported it? ( Can't remember if it had one or two?)
2 . This is the entire point! With any given weight of bombs the B-17 will fly farther at higher altitude and faster! You keep failing to differentiate between what the plane could do and what the masters wanted it to do! This is not a small difference. It is between 11-20% advantage to the B-17 depending on model and mission parameters!
Lancaster =
Ultimate heavy lifter, only rivalled by the B29. Wrong! Versatile in terms of bombload, due to uninterrupted 33 feet long, but very low bomb bay. Runs out of breath at higher altitude. Poor defenses, and fragile construction WO much armor.
If I had to summarize this last, I'd say that the long bomb bay was more versatile in that the B-17 witch could only carry bombs up to 10' in length. But the B-17's bomb bay was divided in half and twice and a half as tall. It was possible, but very rarely done, to carry two 4,000 pound standard medium case American bombs on each of the two sides, one above the other, FOUR total! It is imposable for the lancaster to match this load. While I do not know the CoG limits, I do know that hanging two 1,000 pounders on the last two racks was, if not forbidden, restricted, because if they failed to release, the plane was lost due to aft CoG excursion. The standard Lanc could not carry this bomb at all because it was too fat to fit inside the regular bomb bay doors! That is why they built the "Cookie"! While it might be possible to fit three of these monsters on the CL hooks, in a plane with bulged doors, I sincerely doubt that anyone would do it for the
afore mentioned CoG reason if the last bomb hangs up.
If you limit your argument to later model Lancasters with the requisit capacity to carry 18,000 pounds, it can carry 400 pounds more bombs than the B-17, but to a much shorter range! If we ask that the maximum weight of incendiary bombs be carried, then the B-17 with it's 42 bomb shackles, to the Lancs 15, wins hands down! What type of bomb did the RAF switch to late in the war when the discovered that fire bombs were five and a half times as effective at high explosives? It can load up to 40 each 440 pound incendiary cluster bomb units! Not that this would normally be done, but loading 34 in each B-17 was done on at least one occasion that we have pictures of! 34X440 pounds = 14,960 pounds! How many pounds of incendiaries could the lancaster carry from the charts you posted previously?
But now the Piece de la resistance! How would the two aircraft have done if their respective missions were swapped?
The Lancaster forced to fly over Nazi held Europe in broad day light WO fighter cover and in the face of visually directed Flack? We already know how the B-17 faired. But let us take an excursion down fantasy lane;
1. The Lanc has to add 4,000 pounds of armor, weapons and ammunition. Subtracting the same weight from pay load! ( Just to make absolutely certain that we all understand this point, remember that the Lancaster's average bomb load for the war was under 8,000 pounds and the B-17's over 4,400, which means that the B-17 has a >700 pound edge!
2. The rest of the planes fragile construction makes it much easier to shoot down than the B-17. Bad luck!
3. The lower speed and altitude makes it much easier to intercept. More chances for the fragility to suffer 20-30 MM Cannon hits. More bad luck!
4. The slower cruising speed means that the bomber is over enemy territory longer, again providing more chances to the Luftwaffe to intercept! OOOH that's gotta hurt?
5. The lower altitude makes it easier for Nazi Flack to get hits. ( The standard formula for this is the square of the difference in range.) If 20,500' in the B-17, verses 19,000 feet in the Lancaster makes 16.4% more losses to Flack. But wait, the Lanc is more fragile and near misses would be more likely to down the plane. Very more bad luck! But wait, if the Lanc bombs from a more typical altitude and the Fortress from a higher altitude, say 25,000' Vs 16,000' then the Nazi Flack is 244% more likely to hit! This is not as big a thing as it sounds given that losses to Flack were 1~2% at worst including medium level bombing by B-25s and 26s. But when you consider that there were 787 planes on the raid you mention, that is an extra 21.4 planes lost?
6. The reduced L/D requires the Lancaster to carry fewer bombs and more fuel to distant targets. That means more missions to any single target, thus more chances to intercept. More shuttle missions landing in Russia. There are just too many permutations of this line of argument to continue with a straight face.
On the other side of the coin;
The B-17 gets to shed 3,000 pounds and carry more bombs to a longer range than the Lanc by a huge margin. The weight of fuel for the return to base trip is less by the L/D of that weight. Or they just keep the armor and dump some of the crew and waist guns/ammo? Or wait, they dump it all but the tail gunner and ventral ball turret gunner, pilot, co-pilot, and bombardier/radio operator. Five crew is a thousand pounds plus the weight of the armor protecting them, may be 2000 pounds to play with. OR shed all of the turrets and six crew, it is according to one poster here 50 MPH faster! What if after switching mission profiles the B-17 was modified just for night missions? Then it would be almost as fast as a Mossy, fly higher, may be, and certainly carry much more bombs! How hard would it be to down a B-17 with Mossy speed and B-17 toughness? Right!
Now you tell me which is the better plane! Crews of both aircraft =
Heroes. Absolutely!!!
Regards,
Stewart.