A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Military Aviation
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Pushing the limit



 
 
Thread Tools Display Modes
  #11  
Old September 8th 03, 09:11 PM
external usenet poster
 
Posts: n/a
Default

(Peter Stickney) wrote:

In article ,
"Gord Beaman" ) writes:
(Arie Kazachin) wrote:

In message - "Mycroft" writes:

Can anyone think instances when an AC has been push beyond it's limits or
has done things it was never supposed too? The reason I ask is that I
recently read that when Lancasters were carrying Grandslams during WW2 the
engines were seriously over reved at take off because the bomb exceeded the
AC max payload weight by aprox 9000lbs.

Myc


I wonder where people get these ideas?...Lancaster engines (at
least the Merlin 224/225 models) cannot be over=revved (they have
'Constant speed controls' on the props and they cannot be
over-boosted either, they have ABC units installed (Automatic
Boost Controls). So where do these stories come from?...or were
they fitted with some other types of engine?.


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.

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.

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).
--

-Gord.
  #12  
Old September 9th 03, 02:59 AM
Big Dave
external usenet poster
 
Posts: n/a
Default

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


  #14  
Old September 9th 03, 03:57 AM
Peter Stickney
external usenet poster
 
Posts: n/a
Default

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
  #16  
Old September 9th 03, 05:39 AM
external usenet poster
 
Posts: n/a
Default

(Peter Stickney) wrote:

Let's just say that if I'm talking through my hat, please do call ne
on it.


Ok...yer on...we'll keep yer on the straight 'n narrow!...


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.


Yes, it starts this Thursday, runs for 4 days.

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.


Hell, yes!...but you could just email it and we can print it
here. Thanks, )

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?


Cripes yes!...a favourite punishment for young airmen 'who were
feeling their oats' was 'polish detail'. I'll never forget the
smell of 'Never-dull', that polish soaked
'cotton-batting-in-a-can' that we used. did a great job on
bare aluminum too.

Can't find the Lanc on the Pine tree Line site, that's a
humongous site, really big.
--

-Gord.
  #17  
Old September 11th 03, 02:42 PM
David Lesher
external usenet poster
 
Posts: n/a
Default

"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  
Old September 11th 03, 03:59 PM
Les Matheson
external usenet poster
 
Posts: n/a
Default

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  
Old September 12th 03, 04:25 AM
Walt BJ
external usenet poster
 
Posts: n/a
Default

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  
Old September 12th 03, 03:57 PM
Alan Minyard
external usenet poster
 
Posts: n/a
Default

On 11 Sep 2003 20:25:43 -0700, (Walt BJ) wrote:

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


Of course you want to be *really* sure that you don't load a 47 tail
heavy. That makes for a very short, very interesting flight :-)

Al Minyard
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cessna 182T w. G-1000 pirep C J Campbell Instrument Flight Rules 63 July 22nd 04 07:06 PM
Lost comms after radar vector Mike Ciholas Instrument Flight Rules 119 February 1st 04 12:39 AM


All times are GMT +1. The time now is 03:53 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AviationBanter.
The comments are property of their posters.