Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: caldera on September 09, 2011, 08:30:54 PM
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According to the AH speed chart, the Lanc hits its top speed of 277 at 14k. Reaching the same peak again around 18k, before slowing down from there on up. The chart only goes to 25k. I was wondering if Lancs are equipped with turbochargers, nitrous or Liquid Schwartz as they seem to go super fast at high altitudes. Including a film of an uber Lanc flying level at 34k, doing a steady 330mph. :headscratch:
http://www.mediafire.com/download.php?0i2q5e0vsh6ulk5
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Superchargers. They use Merlins.
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Apparently, they have a second stage that kicks in over 25k. :rolleyes:
(http://i343.photobucket.com/albums/o460/caldera_08/lancspeed.jpg)
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Apparently, they have a second stage that kicks in over 25k. :rolleyes:
(http://i343.photobucket.com/albums/o460/caldera_08/lancspeed.jpg)
That would be a bug, like the A6M3 had for a bit.
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they probably attached jet engines...:lol
joking aside, probably a bug like the one with the A6M3 like karnak said.
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they probably attached jet engines...:lol
joking aside, probably a bug like the one with the A6M3 like karnak said.
Haha! Oh Wait you just copy what people say to make mindless posts to increase your count.
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Has anyone found the real speed chart for a Lancaster with no ords and %50 fuel (doing a weight comparison). Find the weight comparisons and see how close they are.
Surely, everyone knows an 18 wheeler semi-tractor will go up and through the Rocky Mountains a lot easier and faster with no load in the trailer... right???
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Haha! Oh Wait you just copy what people say to make mindless posts to increase your count.
Obviously you do the same :) to point him out you made a stupid post. Haha!
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I relayed the info to Skuzzy and he replied that the climb rate would be much better when light, but didn't say about the top speed. According to Wiki, the service ceiling on the Lanc is 23,500 feet (and max speed of 280mph at 15,000 feet). If that's even close to correct, how the hell can it even fly at 34,000 feet? Oh, and 50mph faster than its maximum speed. :headscratch:
p.s. I chased a b-17 last night which climbed as high as 37.5k but could only maintain about 36.5k. Wiki states the service ceiling on the B-17 as being 35.6k, so that is pretty close.
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I relayed the info to Skuzzy and he replied that the climb rate would be much better when light, but didn't say about the top speed. According to Wiki, the service ceiling on the Lanc is 23,500 feet (and max speed of 280mph at 15,000 feet). If that's even close to correct, how the hell can it even fly at 34,000 feet? Oh, and 50mph faster than its maximum speed. :headscratch:
are you looking at tas or ias? there is a difference. true air speed (ground speed) could be 400mph while indicated air speed could show only 290mph. from what i've found the service ceiling (maximum altitude where 100ft/min climb can be maintained) is between 23,500 and 24,500 feet. maximum speed of 280-287mph is achieved at 15,000 feet.
this reference claims the absolute ceiling for the mk1 and mk3 is 24,671 feet.
http://www.pilotfriend.com/photo_albums/timeline/ww2/Avro%20Lancaster.htm (http://www.pilotfriend.com/photo_albums/timeline/ww2/Avro%20Lancaster.htm)
not sure how it could get to 34,000 feet with anything but fuel on board, but hey it's ah, ya just never know.
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are you looking at tas or ias? there is a difference. true air speed (ground speed) could be 400mph while indicated air speed could show only 290mph. from what i've found the service ceiling (maximum altitude where 100ft/min climb can be maintained) is between 23,500 and 24,500 feet. maximum speed of 280-287mph is achieved at 15,000 feet.
this reference claims the absolute ceiling for the mk1 and mk3 is 24,671 feet.
http://www.pilotfriend.com/photo_albums/timeline/ww2/Avro%20Lancaster.htm (http://www.pilotfriend.com/photo_albums/timeline/ww2/Avro%20Lancaster.htm)
not sure how it could get to 34,000 feet with anything but fuel on board, but hey it's ah, ya just never know.
I was chasing the Lanc and got the speed from the film viewer. Thanks for that info. That tells me his plane was flying 10,000 feet over absolute ceiling.
Absolute ceiling means quite literally that you cannot fly any higher. I also timed his climb. He averaged 750ft/min from 19,000ft to 34,000ft, getting there in 20 minutes.
I still have the complete film if anyone wants to review it.
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caldera,
What do you mean "absolute ceiling"? That it was going too fast is obvious, but I think you don't understand what the RAF meant by an aircraft's ceiling. All that meant was the altitude at which an aircraft's climb rate dropped below 500ft/min. You could go higher, but operationally it wasn't really useful.
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caldera,
What do you mean "absolute ceiling"? That it was going too fast is obvious, but I think you don't understand what the RAF meant by an aircraft's ceiling. All that meant was the altitude at which an aircraft's climb rate dropped below 500ft/min. You could go higher, but operationally it wasn't really useful.
might want to correct that karnak...service ceiling = 100ft/min.
http://en.mimi.hu/aviation/service_ceiling.html (http://en.mimi.hu/aviation/service_ceiling.html)
combat ceiling is sustained 500ft/min.
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thats how the RAF did fighters, not sure if they used the same for bombers (500fpm is pretty good for an EW buff) :headscratch:
edit: quick offline test from 30k base:
~51,000lb, 3x2k bombs (they look like 2ks in the film, might be 1ks), ~25%
@30k 542fpm
~71,000lb, 14x1k bombs, ~100%
@24k maintains level flight
mass makes a big difference ...
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caldera,
What do you mean "absolute ceiling"? That it was going too fast is obvious, but I think you don't understand what the RAF meant by an aircraft's ceiling. All that meant was the altitude at which an aircraft's climb rate dropped below 500ft/min. You could go higher, but operationally it wasn't really useful.
The page Gyrene81 quotes above has this passage:
Performance: (Early B.Mk I) Maximum speed 275 mph (443 km/h) at 15,000 ft (4572 m). (Late B.Mk I) Maximum speed 287 mph (462 km/h) at 11,500 ft (3505 m), 275 mph (443 km/h) at 15,000 ft (4572 m), 260 mph (419 km/h) at 19,400 ft (5913 m); cruising speed 234 mph (377 km/h) at 21,000 ft (6401 m), 200 mph (322 km/h) at 15,000 ft (4572 m); stalling speed (clean) 95 mph (153 km/h) at 60,000 lbs (27211 kg); normal service ceiling 23,000 ft, nominal service ceiling 24,500 ft (7468 m); absolute service ceiling 24,671 ft (7500 m); climb to 20,000 ft (6096 m) in 41 minutes and 40 seconds; initial rate of climb 250 ft (76 m) per minute with full bombload. In a hard dive the prototype aircraft achieved speeds reaching almost 400 mph (644 km/h) with production aircraft (operational loadout) being limited to 360 mph (578 km/h).
Another interesting note in this paragraph is that the plane could almost reach 400mph in a hard dive (with the prototype - production aircraft, only 360mph), whereas in AH, I have film of one doing 484mph up high.
Absolute ceiling:
http://www.thefreedictionary.com/absolute+ceiling
The highest altitude at which an aircraft can maintain level flight.
Engine power for the various Lanc variants (from same source):
Powerplant: (B.Mk I) Initially four Rolls-Royce Merlin XX or 22 Vee 12-cylinder liquid-cooled inline engines each rated at 1,280 hp (955 kW) for take-off and 1,240 hp (925 kW) at 2,850 rpm at 10,000 ft (3050 m) with a maximum power rating of 1,480 hp (1104 kW) at 3,000 rpm at 6,000 ft (1830 m). Late production B.Mk I aircraft being equipped with four Rolls-Royce Merlin 24 Vee 12-cylinder liquid-cooled inline engines rated at 1,620 hp (1209 kW) for take-off and 1,240 hp (925 kW) at 2,850 rpm at 10,000 ft (3050 m) with a maximum power rating of 1,640 hp (1223 kW) at 3,000 rpm at 2,000 ft (610 m). (B.Mk II) Four Bristol Hercules VI 14-cylinder two-row air-cooled radial engines rated at 1,615 hp (1205 kW) for take-off and 1,675 hp (1250 kW) at 2,900 rpm at 4,500 ft (1370 m) with a maximum power rating of 1,675 hp (1250 kW) at 2,900 rpm at 4,500 ft (1450 m). The radial engined Lancasters had a higher top speed but also had a higher fuel consumption. (B.Mk III) Four American-built Packard Merlin 28 Vee 12-cylinder liquid-cooled inline engines each rated at 1,300 hp (970 kW) for take-off, or four American-built Packard Merlin 38 (Merlin 22) Vee 12-cylinder liquid-cooled inline engines each rated at 1,390 hp (1037 kW) for take-off. Some later B.Mk III aircraft had the American-built Packard Merlin 224 (Merlin 24) Vee 12-cylinder liquid-cooled inline engines each rated at 1,620 hp (1209 kW) for take-off. All Merlin engines used a mechanically driven, two-speed, single stage, centrifugal supercharger. Note: Rolls-Royce engine marks up to XX (twenty) are distinguished by Roman numbers, while marks above that were distinguished by Arabic numericals.
thats how the RAF did fighters, not sure if they used the same for bombers (500fpm is pretty good for an EW buff) :headscratch:
edit: quick offline test from 30k base:
~51,000lb, 3x2k bombs (they look like 2ks in the film, might be 1ks), ~25%
@30k 542fpm
~71,000lb, 14x1k bombs, ~100%
@24k maintains level flight
mass makes a big difference ...
If the service ceiling(100ft/min climb) is more or less 23,000ft, it shouldn't be climbing five times that rate at 30,000ft with eggs aboard. :headscratch:
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I think you missed my point - my 2nd test at 71,000lb shows an absolute ceiling of 24k, which is consistent with the test data. the only references I can find to the test weights for speed and absolute/service ceilings are at 65,000lb.
the AH lanc in the film only had 3 bombs left and probably had hardly any fuel left like my 1st test at 25% at 51,000lb (could have been alot less - you can glide a long way home from 30k+).
thats at least 30% less weight ...
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That may be how it is programmed in AH, but absolute ceiling is only acheived in testing with optimal conditions (certainly not with a full crew, ordnance, ammo and other supplies aboard), not in combat. If the article states that 24,671 is the absolute ceiling, then by definition that is as high as the plane can go.
Aside from the altitude question, what about the max speed question? AH itself claims top speed is 277 at 14k.
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the RAF pilot notes, test data, my 2nd offline test and (I assume) the AH charts are all figured at ~65,000lb and are consistent.
the lanc in the film and my 2nd test are tested at 40-50,000lb, at least 30% lighter, and are consistent.
...
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The Lancaster in AH is a Mk III, not an early Mk I. That may be playing a role as well.
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Aside from the altitude question, what about the max speed question? AH itself claims top speed is 277 at 14k.
thats a fair point - whats the IAS for 330TAS @34k in AH? :headscratch:
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Looking at the AH climb rate chart, the Lanc's climb drops dramatically from around 14k to practically nothing at 23k. Doesn't that have something to do with the way the superchargers are geared? They engines make less power after the plane reaches peak altitude (14k). I'm not saying you are wrong RT, but doesn't engine performance factor into this? The plane in the film may weigh a lot less, but at 34k it is also making less power.
The Lancaster in AH is a Mk III, not an early Mk I. That may be playing a role as well.
I checked out various sources and used specs for Late B. Mark I and MarkIII (which are nearly identical performance) and sent them to Skuzzy.
thats a fair point - whats the IAS for 330TAS @34k in AH? :headscratch:
Don't have the patience to find out. :lol
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From the update:
Fixed some potential plane performance issues that could occur above the normal service ceiling.
(http://i343.photobucket.com/albums/o460/caldera_08/newlanc.jpg)
WOOOOHOOOO! No more uberspeed high alt Lancs. WTG HTC! :x
It flies loaded (61,000 lbs) 279 mph at 25k. Climb rate at that weight at 25k is @333 fpm.
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Yeah, but it wasn't just the good ol' Lanc, any guesses/ideas as to all the other aircraft that got adjusted?