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#12
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Actually I got the info from a filmed interview of a Grandslam mission pilot
who stated that both he and the flight engineer had the throttle levers pushed hard against the stops to get a few extra revs out of the engines as "The cow was bloody overloaded & did not want get off the damm ground". B D aka Mycroft |
#13
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#14
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In article ,
"Gord Beaman" ) writes: (Peter Stickney) wrote: Well, with a Lanc, if it wasn't a Merlin 24/224/225, it would have been a Merlin XX or 22. The only differnece being that the Emergency adn Takeoff ratings were a bit lower. (Takeoff 3000R/+12 for the Merlin XX, 3000R/+14 for the 23, and Emergency ratings of 3000R/+14 in Low Blower and 3000R/+16 in high) They still had the boost controls, and, of course, the COnstant Speed props. As for wher the storys come from, they pop up all the time. Somebody hears something that they think they understand, get it a bit wrong, and as they repeat it, it grows. Yes they do don't they?. As to your power limits for the 224/225 some aspects don't look as I remember them. (Now take note that this was nearly 50 years ago so cut me some slack) I thought that the max RPM was 2900 (remember that I have some 16 years on R-3350's with 2900 RPM limits so this might be the reason that I think that). Also I know that the max boost was 18 in low blower. I don't remember what the boost limits were in high blower but it seems odd that they'd be _higher_ than in low. So as not to mislead you about those power limits I have two old F/E friends here in town who flew Lancs so I asked both of them just now. One isn't sure of the max RPM but 'thinks' that it's 2900 and the other is 'sure' that it's 2900 and they both agree with me about the boost limits which were 9 pounds (at the 'gate'), 14 pounds at full throttle and with the 'boost over-ride' pulled (which cut out the Automatic Boost Control - known as 'pulling the tit') gave ~18 pounds. It seems that I wasn't explaining myself too well last night. (I _told_ the wife that all that yard work would screw up my brain) You are, oc course, absolutely correct about the Merlin 24/224/225 power settings. In my own muddy way, I was referring to the engines used in most of the earlier wartime RAF Lancs, which were, of course, the earlier models, which weren't rated at such high boosts. According to my Lanc III Pilot's notes (I finally managed to get a copy, Hooray!), your quorum of FEs is quite correct aabout the gate settings. The whole question of power settings on Brit engines puzzles me somewhat, to tell you the truth. To take an example, I've been working on some engineering analysis of the Mosquito, so I've got a pretty good handle on what the engine performance and airplane performance numbers are. The only catch is, most of the published airplane performance numbers don't bear any relationship to what I've calculated from the info I have. The published numbers for the 20 series Merlins give, if you're lucky enough to find something other than takeoff power, the Max Power, which I've described above, The Climb Power, which was 2850R/+9 boost, and Max Continuous, which is 2650R/+7. That's all well & good, and normally things can be doped out from this by applying a bit of science. But it appears that the actual trials were flown at the 3000R/+9 gate, which is throwing everything off. I'm not really complaining, mind you. It's turning out to be an interesting study, and should be the basis for an advisory article for other researchers about the importance of knowing the context of what's being tossed around. AS for why the earlier 2-Speed single-stage Merlins had that asymmetrical power setting, with reference to Low & High blower Max Power, what I can figure is that it's due to the lower ambient air temperature at altitude allowing more compression without raising the non-intercooled carburetor inlet temperature beyond some threshold. The engine was certainly capable of producing more - the differences between a Merlin 22 and 24 are more small details and calibration than anything else. I realize that you're a damned fine researcher and have a lot of facts at hand and I feel a little timid about 'instructing' you but I'm very sure of my facts about these a/c. I logged 575 hours as F/E on them. Gord, please do not _ever_ feel shy about correcting or instructing me! I'm not going to learn, otherwise. Barring an unbelievable piece of fortune, you've been able to Be There and Do things that I can only read about. I'd like to think I outgrew the Know-it-all Snot stage about 20 years ago. My research, and the stuff that depends from it, can let me tell what, and how, and, at least in the case of the machines, why, but it can't ever take the place of the people who actually were in the hot seat. Research all I might, it's no substitute for experience. Despite the advancing years, and the thinning numbers, there's still an incredible group of people with real experience that spans more than 60 years, all on tap. Not cold, impersonal mathematics, or stories passed from hand to hand so much that all the edges are worn smooth, but people who were really there, and made it through. (I was going to make a list of the folks here who's opinions and experiences I value, but it started running too long, and I was afraid that I'd leave somebody out, (which would be unfair), so I won't name names.) Let's just say that if I'm talking through my hat, please do call ne on it. They were Lancaster X (MR) with Merlin 224/225 engines as used by the RCAF in Canada for ASW work in the early to mid fifties and replaced in (I think '55) with Neptune P2V-7's (with no jets installed until later). You mentioned that you were going to be attending a gathering of your RCAF/CanForce fellows this fall. I've managed to dig up a beautiful color photo of an RCAF Argus and a USN Neptune formating on each other during the Cuban Missile Crisis. I can swing acanning it, and shooting off a large-scale (B or C size) print of it, if you'd like. Oh, yeah - on the Pinetree Line website there's a rather good quality color image of an ASW Lancaster that suffered a maingear collapse at Stephenville/ Ernest Harmon AB, in the mid '50s. While it's not the most dignifies shot, it's a good study of a workhorse late in its life. Like every other Canadian Military airplane I've seen, it looked to be in remarkable shape - did you guys have people specially detailed to polish 'em? -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
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#16
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#17
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"Les Matheson" writes:
IIRC all the MC-130's and EC-130's that departed Massirah Island for Desert One in 1980 were over gross weight at take off and were pretty severely stressed on landing in the Iranian desert. There were some pretty hairy takeoffs from that site, too. Would it not have been better to takeoff with minimum fuel and then refuel? -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#18
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I believe it was all the fuel in the bladders that was going to be used to
refuel the helos. The bladders couldn't be filled inflight. The aircraft themselves were light on fuel and did tank airborne. Les "David Lesher" wrote in message ... "Les Matheson" writes: IIRC all the MC-130's and EC-130's that departed Massirah Island for Desert One in 1980 were over gross weight at take off and were pretty severely stressed on landing in the Iranian desert. There were some pretty hairy takeoffs from that site, too. Would it not have been better to takeoff with minimum fuel and then refuel? -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#19
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Pushing an airplane beyond its flight manual, FAA-mandated or design
limits is no rarity. Sometimes it happens because of emergency conditions. Sometimes it's operational priority. Sometimes it's because of a (pick the ones that match the situation) dumb/unthinking/ignorant/'high-spirited' operator. BTW a 60000 C47 is about the twice the normal operating weight. but there's no difficulty about taking off overweight as long as nothing breaks. All oen needs is lots of long smooth hard-surface runway. A stiiff headwind is nice, too. Taking off at twice normal weight requires 143% of normal lift-off speed. (Lift is proportional of square of speed). As long as the tires don't blow, the wings bend and break or an engine quits . . . I personally know a man who flew a C47 with 74 people aboard on an emergency wartime evac in Burma. FWIW the 106 that was at the AFA went out to about 2.45M, .45 over its red line (ISTR). The J75 was cranked up about 30% over rated thrust, too. I also know the guy who took a 104A out so far it scorched the paint on his Sidewinders. He never owned up how fast that was except to say it was well past the SLOW light (121C). As for the Lanc engines - adjustments can be tweaked, as was done on the 106 above. I heard N1 on that bird was upped to about 97.5% vice a normal 93. And who here has never exceeded a red line on his personal automobile? Walt BJ |
#20
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