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bean
7th Feb 2022, 08:58
I understand the Vanguard had a Vno of 320 knots, i expect it had a limiting mach number, what was it please? Did the asi have a barbers pole?
Thanks on advance ex Vanguard guys

Herod
7th Feb 2022, 09:47
I've not flown the Vanguard, but from experience of aircraft of that era, I wouldn't expect a barber's pole. I wouldn't think a limiting Mach Number either. Digging into a very old memory bank, the crossover between IAS and Mach occurs about 28,000 ft. Below that, IAS is the figure.

bean
7th Feb 2022, 09:54
Thanks Herod. The q400 as an example has a limiting mach number of .55 so crossover occurs much lower

bean
7th Feb 2022, 09:57
146 was .65 was'nt it?

bean
7th Feb 2022, 10:02
I guess 320 knots may have been limited to a specific lower altitude

dixi188
7th Feb 2022, 10:26
Don't know about the Vanguard.
The L188 electra (similar type) was IIRC Vmo 300kts, Vne 317kts, Mne .615. No mach meter fitted just a placarded limit.
Dixi.

bean
7th Feb 2022, 10:54
Thanks dixi. Interesting topic even though i say it myself!

TCU
7th Feb 2022, 12:49
Extract from the Chapter entitled Vickers Vanguard from Brian Trubshaw's excellent book, Test Pilot:

"Another interesting feature of the Vanguard was the relatively high speed envelope. Demonstration of this was made by flying down the design speed diving line (VD). At about 12,000ft the design limit was some 400kt.".....the aircraft itself handled beautifully...".

He also describes flying the Vanguard on a sales tour between Cairo and Beirut "...did the trip in one hour and five minutes flying at 1,000ft at over 300kt indicated...."

I appreciate there are some gaps in this data and Trubshaw was of course a test pilot flying a manufacturers prototype, but seems the Vanguard was a speedy machine despite being "....a great tub of an aircraft...." (Trubshaw)

Trubshaw records he was rather fond of the Vanguard but his test flying of the type was interrupted by the VC10 development.

bean
7th Feb 2022, 13:09
Thanks TCU. VD would if course be beyond Vno. I'm going to do some tables tomorrow given the Electra speeds Dixi 188 has kindly provided. Bit of work but hey, keeps a retired brain occupied!
I'll post them here

Meikleour
7th Feb 2022, 13:55
bean: I flew 2,000 hrs on Vanguard/Merchantmen but alas the VNE escapes the old grey cells now but what I do remember clearly is we used to climb clean at 290 kts ind. and descend at 300 kts ind. I am also pushed to ever remember flying much above 25,000 ft. Probably as a result of concerns after the rear pressure bulkhead blowout in 1971. Thus Mach was never ever considered.

A cruising TAS of 360 kts was normal so I guess IAS of 280 - 285 ish

bean
7th Feb 2022, 14:26
Thanks, i'm talking about speeds in decent.
i'm going to do some tables based on dixi188s electra figures which i'll post here. Very interesting

Eric T Cartman
7th Feb 2022, 16:55
I can't answer the OP's query but have an anecdote re the Merchantman & speed. I was on Approach Radar at Glasgow in the late 70's when I had to ask a Merchantman to reduce speed from 250 knots as he was rapidly hoovering up the Dan Air Comet ahead of him. I'm sure there was a chuckle in the ABC Captain's reply when he asked what speed I would like. :)

BEagle
7th Feb 2022, 18:17
A cruising TAS of 360 kts would mean, under ISA condtions, an IAS of 282 kts at 17000ft - which I think was the cruising level, if memory serves, of the first airline flight on which I was a passenger from London to Gibraltar with BEA in 1965.

TMN of M0.58

Jhieminga
7th Feb 2022, 18:23
I'm pretty sure that there is no barberpole on the ASI in a Vanguard, but I cannot find the photo to confirm this right now.
This will do: https://www.jetphotos.com/photo/9124318
G-APEP has an interesting ASI with two pointers. The 'barberpole' on the altimeter is no doubt there to indicate no or unreliable altitude information.

Chesty Morgan
7th Feb 2022, 19:29
146 was .65 was'nt it?
The -100 was .69 or .7ish, the -300 could make it all the way to .73 and the -200 was somewhere in the middle.

VMo was 295 for the -100 and 305 for the -300.

megan
8th Feb 2022, 02:55
bean, these are the figures for the Electra C model, the A model differs only in having a Va three knots slower, from the FAA TCDS.


https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1120x541/l_181718946ca4500db1c1bb46a7da385bd22b243e.png
You'll find the speeds for the various BAE 146 models on the FAA TCDS link.

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/BF1202CF2015828A8625827900539C5F?OpenDocument

bean
8th Feb 2022, 06:32
Thanks all. I posted this on the Vanguard facebool group as well and someone came up with the TCA Vmo graph. Follow the line must have been the answer
Different Vmos for different weights and interpolate in between
fl200 zero fuel weight 122500 lbs. Ias 282 mach.58

DaveReidUK
8th Feb 2022, 06:32
In case anyone else is tempted to look, the Canadian TCDS for the Vanguard simply says: "Airspeed Limits - See Airplane Flight Manual".

common toad
8th Feb 2022, 07:33
Jhieminga. Please don’t post pictures like that on a public forum; it will give the children (of the magenta line) nightmares and retired aviators nostalgia pains. Thank you.

bean
8th Feb 2022, 08:38
I'm pretty sure that there is no barberpole on the ASI in a Vanguard, but I cannot find the photo to confirm this right now.
This will do: https://www.jetphotos.com/photo/9124318
G-APEP has an interesting ASI with two pointers. The 'barberpole' on the altimeter is no doubt there to indicate no or unreliable altitude information.
Two pointer ASI seems to have been quite common in the sixties

scotbill
8th Feb 2022, 09:22
The Vanguard was an amazing aircraft perfectly capable of equalling or beating jet block times on sectors up to 1.30. (Equalled but never beat my best Vanguard time on domestic flights on Tridents and 757s).
BEA were right to think there was no need for jets on domestics but the glamour of jets won the day. Difficult to fly well compared to Tridents until you got used to its constant change of trims with power or configuration alteration.
Despite its chunky looks and lack of hydraulic controls it was a very satisfying aeroplane at high speed with a Vne at low level of 331 knots. The closer to that speed the more precise the handling so it is easy to believe reports from Vickers test pilots that above 400 k IAS they preferred the Vanguard to the Valiant jet bomber, LATCC asked me once to deviate on a descent into LHR to allow a 737 to descend through my level because he was faster. My reply, "Well we're doing 320k, what's he doing?" Shortly afterwards a notice appeared in the Control Centre 'Please note that Vanguards descend at jet speeds'.
Heathrow controllers got used to Vanguards being infinitely flexible. I was once diverting to Birmingham over Central London at 10,000 feet when Approach said "28R RVR now 600 metres - are you interested?"
We got in.
For more read my book 'Flight from the Croft (Whittles) 5* on Amazon. Any royalties go to charity..

bean
8th Feb 2022, 09:41
The Vanguard was an amazing aircraft perfectly capable of equalling or beating jet block times on sectors up to 1.30. (Equalled but never beat my best Vanguard time on domestic flights on Tridents and 757s).
BEA were right to think there was no need for jets on domestics but the glamour of jets won the day. Difficult to fly well compared to Tridents until you got used to its constant change of trims with power or configuration alteration.
Despite its chunky looks and lack of hydraulic controls it was a very satisfying aeroplane at high speed with a Vne at low level of 331 knots. The closer to that speed the more precise the handling so it is easy to believe reports from Vickers test pilots that above 400 k IAS they preferred the Vanguard to the Valiant jet bomber, LATCC asked me once to deviate on a descent into LHR to allow a 737 to descend through my level because he was faster. My reply, "Well we're doing 320k, what's he doing?" Shortly afterwards a notice appeared in the Control Centre 'Please note that Vanguards descend at jet speeds'.
Heathrow controllers got used to Vanguards being infinitely flexible. I was once diverting to Birmingham over Central London at 10,000 feet when Approach said "28R RVR now 600 metres - are you interested?"
We got in.
For more read my book 'Flight from the Croft (Whittles) 5* on Amazon. Any royalties go to charity..
Thanks again Scotbill. I've already replied on my facebook Vanguard topic

dixi188
8th Feb 2022, 11:37
Megan,
Thanks for the Electra numbers. At least I remembered the M .615.
I wonder if these figures were the original limits. I think some were changed after the "Whirl mode" crashes.
Sometime I'll look out my manuals if I still have them.
Dixi.

treadigraph
8th Feb 2022, 11:46
For more read my book 'Flight from the Croft (Whittles) 5* on Amazon. Any royalties go to charity..

Highly recommended by this happy customer!

Chrisy
8th Feb 2022, 13:02
Glad to know you're keeping well Bill

scotbill
8th Feb 2022, 14:03
No reason to complain!

DaveReidUK
8th Feb 2022, 14:18
Frustratingly, the day before the OP posted I was on board G-APEP at Brooklands with the grandkids. I noticed a pile of manuals on display, which may well have included a Flight Manual, though I was too busy chatting to the volunteers to pay much attention to the contents.

Jhieminga
8th Feb 2022, 14:40
Jhieminga. Please donít post pictures like that on a public forum; it will give the children (of the magenta line) nightmares and retired aviators nostalgia pains. Thank you.
My apologies, next time I will include a warning. Something along the lines of 'Do not click on this link if you are below ... years of age or are suffering from chronic RR Tyne induced hearing deficiencies.' That should suffice....;)

Another vote for 'Flight from the Croft' here.... actually, just click this link (https://amzn.to/3B8gvBl) and select 'Buy now'! :ok:

Jhieminga
8th Feb 2022, 17:32
At the risk of incurring more nostalgia pain, perhaps this is a useful place to ask the following question. Do the procedures on the photos below look like they are for a Vanguard? The booklet is from Vickers and is simply marked 'Drills' but apart from having concluded that it is for a four-engined turboprop I have not narrowed it down any further. It should be for either a Vanguard or a Viscount of course.

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1200x1600/img_5077_e2f6dc40ce3c1e79dc254bbc360923bb6e2cb135.jpg
https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/1200x1600/img_5078_01604da90ace33ce7a84a3ce65f81b65ce6c30a2.jpg
https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/750x1000/img_5079_bb5b3a71c6b9b4c9d04284170959e7e69f19663b.jpg

BSD
8th Feb 2022, 18:25
I'd say Viscount. It mentions fuel trimmers which the Dart had. The Tyne (or at least the ones I flew) had condition levers.

Also, doesn't mention the start in low ground idle, then the acceleration of the engine up to high ground idle. A feature if the Tyne.

And, wouldn't the Vanguard have had CSDs, hence "check generators charging" might not be quite right.

Discorde
8th Feb 2022, 20:00
Perhaps Vne was variable on the Vibrator. Certainly Vno was. I recall from my 'How to Fly The Vanguard' Notes from 100 years ago: Vno = 303 minus altitude (in thousands of feet).

The alternators were 'frequency wild' - this was OK for e.g. anti-icing tail, props & engine intakes. Transformer/ rectifier units & inverters supplied controlled AC & DC.

Cruise speed was also variable - we set the LP RPMs to 12,500 and accepted whatever IAS it gave us. Other power settings: climb 12,500 (IAS 230 kt), max continuous 13,500, ops nec 13,000. In the cruise TAS was in the region of 330-340 kt.

On the approach the props were in the constant speed range so power setting was judged by fuel flow - approx 600 kg/hr/eng IIRC. Every change of power required rudder trim adjustment. If the slip needle was not centred the a/c would tend to pitch down - something to do with tailplane dihedral (contd. p94)

megan
8th Feb 2022, 23:43
I wonder if these figures were the original limitsdixi, The TCDS from which the figures come are the current revision 14 dated 11th Jan 2010

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/BB0ABA041A44E220862576AC0056B343?OpenDocument

Cedrik
9th Feb 2022, 08:48
The Ferguson tractor engine in the Vanguard limited the speed drastically

bean
10th Feb 2022, 08:45
The Ferguson tractor engine in the Vanguard limited the speed drastically
Earth calling Cedrik. What planet are you on?

India Four Two
10th Feb 2022, 08:57
Cedrik is probably on Planet Standard.

BEagle
10th Feb 2022, 09:53
Surely the original Standard Vanguard had a TR2 engine?

0-60....eventually after 22+ seconds and it would stagger on to 80 mph. Awful thing!!

bean
10th Feb 2022, 10:02
A Ferguson tractot engine could do 0-60 OK just take about 60 years. This thread is going into a high mach number descent

Jhieminga
10th Feb 2022, 12:36
I'd say Viscount. It mentions fuel trimmers which the Dart had. The Tyne (or at least the ones I flew) had condition levers.

Also, doesn't mention the start in low ground idle, then the acceleration of the engine up to high ground idle. A feature if the Tyne.

And, wouldn't the Vanguard have had CSDs, hence "check generators charging" might not be quite right.
Hello BSD, I have had a better look at things and have asked around in the Viscount enthusiast community and it looks like you are correct. That's one puzzle solved for me! I actually did know about the Tyne's low/high ground idle feature thanks to having been on the flight deck for an engine run once. I just didn't think to look for it in the checklist. As for the Viscount and its Darts... I'm even less knowledgable (so that basically equals zero....).

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1600x1423/g_apep_engine3_7a932523e82b7113f143b5064be4a4c871fede60.jpg

kenparry
10th Feb 2022, 16:01
Following the bifurcation of the thread into the realms of car & tractor engines: as a long ago owner of a TR3A, my understanding of the engines of the TR2-3-4 series is that they were derived from a Ferguson tractor engine. Whether the same engine went into the Vanguard, I don't know. But Triumph and Standard were not in the same group of engineering companies, were they?

(With apologies for continuing the drift!)

megan
10th Feb 2022, 16:24
But Triumph and Standard were not in the same group of engineering companies, were theyTriumph cars were produced by Standard, as was the Vanguard, all used the Ferguson engine.

bean
10th Feb 2022, 16:24
What was the Mno of the Ferguson tractor?

DHfan
10th Feb 2022, 18:15
The Standard engine was designed by Standard themselves, for use in their own cars and the Ferguson tractor. It wasn't a Ferguson engine.

longer ron
12th Feb 2022, 07:27
We were over on Skye/Rassay in 2020 for a weeks holiday and came across this 'classic' tractor in lovely condition c/w 'Standard Motor Co' Manufacturing Plate.
Sorry a bit slow posting the pics but we had used the bosses camera and I was away from home yesterday.

https://i.imgur.com/ueA9PNu.jpg

https://i.imgur.com/WpGwmWO.jpg

bean
12th Feb 2022, 10:12
As the originator of this thread
if there are any more posts about tractors i will delete the thread

DaveReidUK
12th Feb 2022, 10:24
As the originator of this thread
if there are any more posts about tractors i will delete the thread

If only you'd ignored the first post that brought up tractors, we'd probably have been still on-topic. :O

bean
12th Feb 2022, 11:01
Davereid. Oh so smug, i used to respect you

Discorde
12th Feb 2022, 11:09
The Vanguard (flying machine) did have tractor propellers bolted on to its Tynes . . .

bean
12th Feb 2022, 11:22
The Vanguard (flying machine) did have tractor propellers bolted on to its Tynes . . .
Ha Ha i like

DaveReidUK
12th Feb 2022, 12:32
Davereid. Oh so smug, i used to respect you

Please yourself. Personally, I've found this a fascinating thread with a number of very interesting on-topic posts. It's not me who's threatening to delete them all.

DaveReidUK
12th Feb 2022, 12:40
Getting back on topic, and apropos the lovely photo in post #38, does anyone know if Brooklands still fire up Echo Papa from time to time ?

Edit: a bit of Googling reveals that it can't be run in its current location. Oh, well ...

megan
13th Feb 2022, 05:29
bean, since I'm a collector of flight manuals I got myself a Air Canada Vickers Vanguard flight manual as a belated birthday present. Extracted figures below

Emergency Descent Speed, 350 knots, sea level to 10,000 feet. Above 10,000 feet reduce airspeed 5 knots/1,000 feet to 275 knots at 15,000 feet

Maximum Operating Speed, Vmo Speed varies with altitude and depends on zero fuel weight, select from graph

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/535x800/vv_441ba30d5c4881d66f760a9adfce6cdfb4916951.png


Manoeuvering Speed, Va 204 knots IAS

Autopilot Engaged Speed, all speeds up to Vmo

Maximum Operating Altitude 25,000 feet

Maximum Crosswind, Take Off 26 knots, Landing 27 knots

Flaps Extended Speed, Vfe (Maximum speeds for extending or flying with flaps extended)

Take Off 20į 200 knots

Approach & Landing 30į or 40į 162 knots

Landing Gear Raising Speed, Vlo 180 knots

Landing Gear Lowering Speed, Vle 200 knots

Maximum for Flight With Gear Down, 200 knots

Landing Light Lowering Speed, 200 knots

Landing Light Operation: Ground operation on “Land” selection is limited to two minutes. No limitation is imposed on the taxi lights.

Minimum Control Speed, Vmcg & Vmca, Refer to the Performance chapter for minimum control speeds on the ground (Vmcg) and in the air (Vmca) with one outboard engine inoperative

Windscreen Wipers Max Operating Speed, 250 knots

PS: There is no barber pole.

john_tullamarine
13th Feb 2022, 08:03
The Vanguard was an amazing aircraft perfectly capable of equalling or beating jet block times on sectors up to 1.30.

Likewise the L188 would show a clean pair of heels to the jets on shorter legs. MEL-LST we used to kill them stone dead for sector time.

Came down impressively as well. I recall one 0-dark-30 LST-SYD sector where we were pretty well empty and decided to run at FL300 (I think that was the maximum level - the memory fades after too many decades), just for fun. ATC near had an apoplexy when we maintained cruise level until passing the north shore of Botany Bay ... still had to put on a bit of power to keep on final slope, landing into the south. Ah, memories.

Herod
13th Feb 2022, 08:28
Hi Megan. That seems to confirm my post way back at the beginning, #2 I think. No limiting Mach number, because at 25,000' it wouldn't come into the range. I still maintain that the change-over from IAS to Mach occurs, for most aircraft, about 28,000'

bean
13th Feb 2022, 10:48
Hi Megan. That seems to confirm my post way back at the beginning, #2 I think. No limiting Mach number, because at 25,000' it wouldn't come into the range. I still maintain that the change-over from IAS to Mach occurs, for most aircraft, about 28,000'
Herod. I'm sure you realize that the reason Vmo imcreases is because Tas is below limiting mach number which for the Vanguard appears to be about 0.58 quite reasonable compared to the Electras.615

bean
13th Feb 2022, 10:50
Thank god we are back on track after drivel abou tractors

bean
13th Feb 2022, 10:52
Megan, many thanks for your very helpful post

Herod
13th Feb 2022, 16:07
Megan: Agreed. My point is that the average turbo-prop isn't going to get high enough or fast enough for Mach to be a factor. We took the C-130 up to the low thirty thousands, and used airspeed limits.There was no way that aircraft would approach a critical Mach No. I've been up higher in jets, which of course are generally faster machines, and on all three types of jet I've operated, the transition from IAS to Mach was around 28,000'.

bean
13th Feb 2022, 16:36
Megan: Agreed. My point is that the average turbo-prop isn't going to get high enough or fast enough for Mach to be a factor. We took the C-130 up to the low thirty thousands, and used airspeed limits.There was no way that aircraft would approach a critical Mach No. I've been up higher in jets, which of course are generally faster machines, and on all three types of jet I've operated, the transition from IAS to Mach was around 28,000'.
Herod, i understand but, with a Vno of 320 knots, if you tried to descend a vanguard from even 20000 feet at that ias you would get a mach number of 0.71 using isa tables. You can't do that in a straight winged turboprop. Take a look at Discordes post. He explains descent speed in the Vanguard. I might add that i have considerable respect for your experience and am enjoying our friendly discourse

Herod
13th Feb 2022, 17:00
Thanks, bean. Yes, agreed about 320 knots, but unless I've read it wrong, Discorde quotes "Vno = 303 minus altitude (in thousands of feet).". That being the case, at 20,000, the Vno would be 283 kts. I'll put a caveat on my statements: I haven't flown a turboprop since early '89 (33 years ago F-27), nor any aircraft since late '04 (17+ years ago B-737), so maybe I'm relying on dim and distant memories. However, I'm also enjoying the thread.

Jhieminga
14th Feb 2022, 09:27
Getting back on topic, and apropos the lovely photo in post #38, does anyone know if Brooklands still fire up Echo Papa from time to time ?

Edit: a bit of Googling reveals that it can't be run in its current location. Oh, well ...
It's not just the location. The Vanguard last moved under her own power on 29th May 2004, after which she was moved across the river to the aircraft park in the museum grounds. By that time the Tynes were already consuming almost as much oil as fuel during each run as the internal seals were, let's say, not in perfect condition anymore. Once in the aircraft park, the Vanguard was positioned in such a way that the engines could be run, and she did enjoy a couple of runs since then. Not all that much though, as the next gremlin that popped up was corroding starters. The housing on the Tyne starters was crumbling away and finding new ones was proving next to impossible (have a look at the images in the first post here (https://cbfsim.co.uk/cbfs_bb/viewtopic.php?t=16886&hilit=Vanguard+starter&start=80) to see what I mean). I am not sure, but I understand that the Transall installation uses a different starter, or a different mounting... don't quote me on that though.

When G-APEP landed at Brooklands in 1996 the expectation was that they would be able to keep her 'live' for a few months at most. In the end she enjoyed eight more years of moving around and a couple more of firing up the Tynes. Not bad if you ask me.

The Vanguard is positioned in such a way that there are no other aircraft behind the left wing, but the Vickers Viking has been reassembled behind the Vanguard's right wing so running those engines wouldn't be very nice for the team looking after the Viking. There is some hard surfacing beneath the props to deal with the threat of picking up stones, dust and such.

I finally found a useful flightdeck photo, and a nice one of all four Tynes running that I took in 2000.


https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/1000x667/g_apepflightdeck_45b7c9753bf5196dc9db896324e51431c6c499ec.jp g
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1000x658/g_apep_running2000_c41eb6718800079222a9f92930edf2254a0fc0dd. jpg

BSD
14th Feb 2022, 10:04
Jhieminga,

Were the Vanguards Tynes fitted with electric starter motors or did it have air turbine starters,

Running the risk of drifting the thread, I'll bet the Vanguard, like all big turboprops almost never needed brakes on landing - pull those props back into fully fine or even reverse pitch and they STOPPED!

Same in flight too (not reverse though!) high speed until very close in, back to idle, props would go into fine pitch and off came the speed.

Happy days.

Jhieminga
14th Feb 2022, 10:28
Electric starters. You could start up from batteries or using a GPU (as shown in my photo above). In later years the 'PEP team was limited to battery starts only as they didn't have a GPU available at the museum. I understand that only the Vanguard and the Belfast used electric starters on the Tynes, the other types all had air starters fitted. I looked back over some old posts about G-APEP and I found some links to an engine run on 31st October 2009.
https://www.youtube.com/watch?v=l2Nnf6IVmN8
https://www.youtube.com/watch?v=tWquHGw83oo
The shutter speed for these videos led to the props appearing to turn really slowly, but I'm sure that they're at low ground idle at least. Also, the image looks a bit squashed horizontally.
This video from 2008 is better, but still doesn't show the correct rpm for the props:
https://www.youtube.com/watch?v=zpooH5MdptM
Right, I should add these as well, the last landing of G-APEP at Brooklands (they ended up a bit short...) and the last time the Vanguard taxied on the Brooklands runway. As for stopping a Vanguard, it is worth pointing out that it landed on the northern half of the runway as Wellington Way had been constructed by then. Because of this, only about 60% of the original runway was available for her to land on.
https://www.youtube.com/watch?v=fmakSwlYLs0
https://www.youtube.com/watch?v=Ej9k3yL5WZM

Herod
14th Feb 2022, 11:25
Hi bean, The talk on crossover led me to take a look at "Handling the Big Jets", by D.P. Davies, once Chief Test Pilot for the ARB. The book is probably long out of print, my own copy being one I was given in '75. There is a graph, which I don't think I can insert, of descent speeds. He is using Mmo 0.88, Vmo 330. The crossover on his graph is at 31,000', with "coffin corner" at 50,000.

Having said that, I'll shut up. My turbo-prop experience is C-130 and F-27, so I have nothing further of value to add to this thread. However, I'll continue to follow you all; always something to learn.

Discorde
18th Feb 2022, 17:05
Were the Vanguards Tynes fitted with electric starter motors or did it have air turbine starters


Vanguard eng start (from memory):

The HP RPM gauges were located to the right of the F/O`s seat. Above his head was the start panel - with a master start switch & four individual start switches. In front of the throttles were 4 start levers. In the START position they allowed a limited fuel flow to the engines. In the NORM position they increased the flow to normal. The transition took several seconds - the indicators would change from START to crosshatch to NORM during the transition. The engine starter was electric and engaged with the HP spool for starting. Starter cutout was automatic when the HP spool reached approx 4000 RPM. The start sequence was eng 4-3-2-1 (can`t remember why).

For BEA operation the sequence and call outs were:

P1: Start 4.
P2: Master start on, starting 4.
P2: HP turning . . . LP turning . . . 3000 (HP RPM).
P1: (Selects Fuel Cock OPEN)
P1: Fuel flow normal . . . Light up.
P2: 4000 . . . Starter cutout . . . Starter light out.
P1: 4 stable . . . Start 3 (&c)

The engine stabilised at low ground idle. Then P1 would move the start lever to RUN.

P2: 4 running (indicator cross hatch).

P1 would monitor turbine gas temp, which would rise during RPM increase and then drop back as the engine stabilised at ground idle. When all engines were running at ground idle the master start switch was selected off by P2.

I can’t remember the prop RPMs at low ground idle (when you could see the individual blades) and ground idle (when they turned into a blur). Cruise prop RPM was in the region of 900 IIRC, with LP RPM 12,500.

More Vanguard trivia in ‘The Damocles Plot’.

megan
20th Feb 2022, 05:29
Discorde, from the Air Canada manual, in a bit of a rush, will look up RPMs tomorrow.


https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/643x792/vv8_301f3890cbc5bd3bed44173b07b82f4cc6e976e3.png
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bean
20th Feb 2022, 07:21
Megan the Tynes fitted Canadian Vanguards were more powerful than the BEA ones

sycamore
20th Feb 2022, 11:51
On C-130s,the inboard engines were started first,then outboards....logic was ,if an inboard caught fire,you could fight it without having a whirling prop to get past...

DaveReidUK
20th Feb 2022, 13:13
Vanguard eng start (from memory):

The HP RPM gauges were located to the right of the F/O`s seat. Above his head was the start panel - with a master start switch & four individual start switches. In front of the throttles were 4 start levers. In the START position they allowed a limited fuel flow to the engines. In the RUN position they increased the flow to normal. The transition took several seconds - the indicators would change from START to crosshatch to RUN during the transition. The engine starter was electric and engaged with the HP spool for starting. Starter cutout was automatic when the HP spool reached approx 4000 RPM. The start sequence was eng 4-3-2-1 (can`t remember why).

My memory might be failing me, but I seem to recall from watching many Vanguard starts, from both inside and outside, that No 3 was usually first.

Jhieminga
20th Feb 2022, 19:38
The Air Canada manual in post #65 agrees with your memory!

brakedwell
20th Feb 2022, 21:59
My memory might be failing me, but I seem to recall from watching many Vanguard starts, from both inside and outside, that No 3 was usually first.

I think most UK built four engined turboprop aircraft started number three engine first, followed by number two, four and then one. I am sure we used this order on the Britannia and Argosy.

ancientaviator62
21st Feb 2022, 07:46
IIRC on the RAF C130K we started the engines in the order of 3,4,2,1.

bean
21st Feb 2022, 10:36
I think most UK built four engined turboprop aircraft started number three engine first, followed by number two, four and then one. I am sure we used this order on the Britannia and Argosy.
Hi Brakedwell. Most of the Viscounts i ever saw, and there were many, stsrted 4321

brakedwell
21st Feb 2022, 10:40
Never flew theViscount. but I am almost certain we used to start number three engine first on the Argosy.

dixi188
21st Feb 2022, 12:09
IIRC the Viscount 700s had hydraulic pumps on the outboard engines and the 800s had them on the inboards. Not sure if that affected the start sequence, but when taxiing in the 700s used 1 and 4 and the 800s used 2 and 3.
Electra (not British) always started no 4 first as that was the only engine with a 2 speed gearbox for the generator, so that all ground equipment could be removed, (GPU and air start), before up shifting to crossbleed start the other engines.

DH106
21st Feb 2022, 16:54
IIRC the Viscount 700s had hydraulic pumps on the outboard engines and the 800s had them on the inboards. Not sure if that affected the start sequence, but when taxiing in the 700s used 1 and 4 and the 800s used 2 and 3.
Electra (not British) always started no 4 first as that was the only engine with a 2 speed gearbox for the generator, so that all ground equipment could be removed, (GPU and air start), before up shifting to crossbleed start the other engines.

Not all 700's - only the very early 701's of BEA and 708's of Air France had the pumps on the outers I believe. They'd routinely shut down the inners when taxiing in rather than the more usual outers.

BSD
21st Feb 2022, 18:34
CL44: (RR Tyne 515 mk. 12) start sequence 2 then 1. With 2 & 1 running in low ground idle, accelerate into high ground idle. When stable, generators (via CSDs) cabin supercharger (#2 and #3) on line and then same process for 3 & 4. As a result, some time would elapse after 2 & 1 were started before starting 3 & 4 could begin.

Air turBine starters powered only by a ground air start unit- not from the pneumatic manifold.

Max weight take-off one fine morning from Mombasa, with 2 & 1 running the ground crew disconnected the air start and cleared off. By the time it was brought back, the temp had risen too high to allow take-off. Back to the hotel until early evening when the temperature hsd dropped!

megan
22nd Feb 2022, 05:11
RPM's, reduction gearbox is 15.605:1


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DaveReidUK
22nd Feb 2022, 06:42
My memory wasn't playing tricks on me. Merchantman at Liverpool, 1995:

nZWl2zFY5-E

Interesting to note that, as well as No 3 being started first as per my recollection (9:00), taxy in after landing was on the outers only (1:30).

ATNotts
22nd Feb 2022, 11:03
Hi Brakedwell. Most of the Viscounts i ever saw, and there were many, stsrted 4321

From my spotting days at BHX I too seem to recall that the BEA / BA 800s and British Midland 810s both started in the order 4,3,2,1 but taxied on to stand using just 3 and 2. Britannias a recall starting 3,4,2,1 and for the life of me I can't remember what order Vanguards used.

Drift of thread here, but did the first generation jets (707 and DC8) start 3,4,2,1? I seem to recall they did but the memory might be playing tricks.

Discorde
22nd Feb 2022, 11:27
Interesting to note that, as well as No 3 being started first as per my recollection (9:00), taxy in after landing was on the outers only (1:30).

I'm almost certain that the BEA start sequence was 4-3-2-1 (I flew for 5 years on this fleet). Also the Tynes on the BEA fleet had different limits from the TCA aircraft:

permitted T/O LP RPM range 15,050 (min) to 15,500 (max)
max continuous HP RPM 17900

Except at high airports temps min torque for take off was 430 units (engines 2 & 3) and 450 for 1 & 4. This was because the inners also powered the pressurisation compressors. During conversion to Merch config the eng 2 compressors were removed, presumably to reduce costs. At high airport temps the HP cock trimmers were set to lower settings, which of course reduced the min required T/O torques.

It looks like the TCA Vanguards cruised at higher LP RPM than BEA. Maybe fuel economy (and maintenance cost) was less critical in those days.

bean
22nd Feb 2022, 12:27
I think most UK built four engined turboprop aircraft started number three engine first, followed by number two, four and then one. I am sure we used this order on the Britannia and Argosy.
High Julien/Discorde. Vanguards were frequent Jersey visitors im the mid 60s and i always remember the start sequence being 4321
you are right

Discorde
23rd Feb 2022, 18:20
Another VC9 quirk - there were many: the available flap settings were UP, CLIMB, TAKE OFF, APPROACH and LAND (not degrees as in the TCA aircraft). The CLIMB setting was a mod introduced by Vickers when test flying showed that below 200 kt with flaps UP wake turbulence from the wing impacted the tailplane, causing airframe buffet. The CLIMB setting directed the wing downwash further down enough to remove the buffeting. The oddity was that this setting could not be selected when extending the flaps, only during retraction. So, if required to hold the procedure was:

- speed reducing below 200 kt, select flap lever to TAKE OFF
- when the flap gauge showed them travelling beyond CLIMB, select the lever back to CLIMB and check that that's the setting they achieved
- reduce to holding speed (175 kt IIRC).

I am also pushed to ever remember flying much above 25,000 ft. Probably as a result of concerns after the rear pressure bulkhead blowout in 1971.

Hi Meikleour

The flight levels for BEA ops were possibly standardised at 190 (eastbound) and 180 (westbound) prior to the accident to 'EC, which was cruising at FL190 when the bulkhead failed. IIRC the BEA max was FL270.

brakedwell
23rd Feb 2022, 20:55
bean: I flew 2,000 hrs on Vanguard/Merchantmen but alas the VNE escapes the old grey cells now but what I do remember clearly is we used to climb clean at 290 kts ind. and descend at 300 kts ind. I am also pushed to ever remember flying much above 25,000 ft. Probably as a result of concerns after the rear pressure bulkhead blowout in 1971. Thus Mach was never ever considered.

A cruising TAS of 360 kts was normal so I guess IAS of 280 - 285 ish

I remember the BEA Vanguard going down after the rear pressure bulkhead blowout as I was flying an RAF Britannia above and behind it. I canít remember whether it was over France or Belgium when we on our way from Akrotiri to Brize Norton. We saw it go down, but didnít realise what had happened at the time.

megan
24th Feb 2022, 00:53
Originally Posted by Meikleour View Post (https://www.pprune.org/aviation-history-nostalgia/645036-vanguard-limiting-speeds.html#post11181070)
I am also pushed to ever remember flying much above 25,000 ft.The TCA manual is dated 1968 and lists a max operating altitude of 25,000, so before the bulkhead failure, but manual does provide cruise control charts to 29,000.

Discorde
24th Feb 2022, 13:32
After 'EC the fleet was restricted to max FL100 and limited cabin diff (don't remember the exact figure) until all the rear bulkheads had been checked. Ops over the Alps and Pyrenees had to be rerouted. Later, when normal pressurisation settings were restored, the normal FL180/190 levels were used, although some Capts elected to reduce cabin diff 'just to be sure'.

blind pew
24th Feb 2022, 14:25
Was near to ghent..my wife’s home city.

Meikleour
24th Feb 2022, 14:43
Diff was restricted to 2.5 psi
Did one memorable LHR-EDI at FL070 in daylight - very scenic!!

brakedwell
25th Feb 2022, 21:22
Diff was restricted to 2.5 psi
Did one memorable LHR-EDI at FL070 in daylight - very scenic!!

That is the sort of height we used fly our Ansons from Bovingdon to Edinburgh.

Meikleour
25th Feb 2022, 21:31
That is the sort of height we used fly our Ansons from Bovingdon to Edinburgh.


Indeed! But I don't think the Anson would have done 360 kts!!!

brakedwell
25th Feb 2022, 21:38
Indeed! But I don't think the Anson would have done 360 kts!!!


Lucky if we got 130 kts with a full load of 8 pax!

scotbill
4th Mar 2022, 07:18
One of the Vanguard quirks I haven't seen mentioned is that X-winds from the right were easier than those from the left.
It was customary to initiate the flare with power on giving better flow over the elevator. When the throttles closed there was a yaw to the left which was helpful in a right x-wind but aggravated the effect from the left. I assumed this was gyroscopic effect of those huge props in the flare.
If you wanted a short landing you could close the throttles before the flare - provided you were ready for the necessary heave!

pax britanica
5th Mar 2022, 15:17
Growing up next to LHR BEA Vanguards were always in evidence as the flew all three shuttle routes almost hourly plus a lot of other busy routes. Although I flew in Viscount , F27, Herald I never flew on a Vanguard

Compared to the other props still around it was quite a big beast with that double bubble fuselage so having enjoyed this thread I am curious to know why the Vanguard was so fast as everyone seems to agree it was . Aerodynamics or the sheer power of those mighty Tynes?

PB

Herod
5th Mar 2022, 17:19
the sheer power of those mighty Tynes? "Hey, they work well in the Vanguard; let's try them on the Belfast...oh"

megan
6th Mar 2022, 01:13
What was the problem with the Tyne on the Belfast Herod?

Herod
6th Mar 2022, 07:56
What was the problem with the Tyne on the Belfast Herod?

I'm no expert on the Belfast, but my understanding is that it has more or less the same engine power, but is considerably heavier, and much more "Draggy". A useful load-carrier.

brakedwell
6th Mar 2022, 08:40
I remember there was a problem with the Tynes on the Belfast initially. In the mid to late sixties I flew an RAF Britannia from Lyneham to Bahrain direct with two replacement Tynes for two Belfasts which needed engine changes. Belfasts were also suffering from too much drag at that time, which I believe was partially cured by fast back strakes added to the the rear end.

dixi188
6th Mar 2022, 10:46
Former colleagues who flew it called it the "BELSLOW"

pax britanica
6th Mar 2022, 14:27
One has to wonder what on earth possessed the Govt and RAF to build the Belfast in the first place. By then the admitted smaller c130 was well establshed and used by virtually all the worlds airforces outside the Warsaw pact . I know the Belfast was a lot bigger but...

Herod
6th Mar 2022, 15:43
One has to wonder what on earth possessed the Govt and RAF to build the Belfast in the first place.

I suspect a clue is in the name.

Agreed about the "Belslow". On the C-130 we regularly passed them. 10,000' higher and 40 kts or so faster.

dixi188
6th Mar 2022, 17:01
Wasn't the Belfast built to carry the Blue Streak missile?

bean
6th Mar 2022, 18:00
I suspect a clue is in the name.

Agreed about the "Belslow". On the C-130 we regularly passed them. 10,000' higher and 40 kts or so faster.
Ah yes, but, what payload were you carrying and what payload were they carrying
Remember that the MOD had to charter the civiliansed belslows to take outsized loads to Ascencion for the fleet during the Falklands war

Herod
6th Mar 2022, 20:09
bean,

I'm not criticising the Belfast's carrying capacity. It was capable of carrying two Wessex helicopters, and five of them delivered ten Wessex to Changi in '70, as part of Operation Bersatu Padu.

condor17
7th Mar 2022, 09:41
Herod , just to say your memory is correct .. Was taught in '74 to climb at 320kts IAS to FL 280 then at M0.80 upwards . FL280 being the crossover point . Had to wait 'til '82 to fly with Capt. Bill . Much later the ATP was akin to a 'Van in the flare , Those massive props gave you an effect of a blown wing , pull power back too early and propwash V squared , stopped the lift immediately , nose dropped and wing stopped flying , Thus Massive heave with feet on the dashboard.
Similar effects on 733 family . Big fan effectively blew the flaps , thus power reduced after round out commenced .
732s , S111s etc. power could be reduced before flare , wing kept flying [ Non blown wing/flaps ] as intake air came into engine well before the wing and exhaust air out well aft of the wing . Thus wing flew and a/c ' floated ' until momentum and lift decayed .

rgds condor .

kenparry
7th Mar 2022, 10:59
condor17:

On the 732, that's not the whole story. The -ADV version would drop like a brick if you took power off before the flare, the basic -200 was more tolerant. Yes, that I did learn the hard way. There were significant differences in LE slat extension between the two, which probably accounted for the differing behaviour.

bean
7th Mar 2022, 11:27
Going right back the begining of my thread, Dixi188 and Megan gave us the Mne and Vne for the Electra. 0.615 and 364 knots It was also stated that the cross over point was 8000 feet
I've looked at the ISA tables and yes,
0.615 mach 8000 feet equals 8000 364 knots IAS. The profile is very similar to that in Discordes post descent in IAS 303 knots less 2 knots per thousand feet.
Herod, do you have the C130 limits to hand out of curiosity?

Herod
7th Mar 2022, 22:07
Sorry bean, I haven't. However, I'm certain that we never used Mach. The old girl wasn't that fast, so it was IAS, at least as far as I ever went in her. I think FL 310.

Meikleour
8th Mar 2022, 09:53
A point that may interest the readers: Many years ago I had a conversation with the test pilot who was tasked with clearing the Belfast for in-flight refuelling. He told me that it failed the trials as a result of the characteristics of the Tyne engine control response - I forget the details constant speeding versus RPM changes in the scheduling (unlike the C130) Perhaps someone can confirm this because many photos of the Belfast show them fitted with probes.

bean
8th Mar 2022, 10:44
A point that may interest the readers: Many years ago I had a conversation with the test pilot who was tasked with clearing the Belfast for in-flight refuelling. He told me that it failed the trials as a result of the characteristics of the Tyne engine control response - I forget the details constant speeding versus RPM changes in the scheduling (unlike the C130) Perhaps someone can confirm this because many photos of the Belfast show them fitted with probes.
Might be an idea to post this on the militaru forum.
The Tynes fitted to the CL-44 and Belfast produced 5730 SHP and drove 16 feet diamater props. What a beast!!!
The RAF pilots notes for the Belfast are available on flightmanualsonline.com.
Could make interesting reading for $9.95!

Discorde
8th Mar 2022, 10:59
One of the Vanguard quirks I haven't seen mentioned is that X-winds from the right were easier than those from the left.
It was customary to initiate the flare with power on giving better flow over the elevator. When the throttles closed there was a yaw to the left which was helpful in a right x-wind but aggravated the effect from the left. I assumed this was gyroscopic effect of those huge props in the flare.
If you wanted a short landing you could close the throttles before the flare - provided you were ready for the necessary heave!

Just as well the Vibrator never ventured into the non-equatorial Southern hemisphere! Crosswind landings would have been trickier!

Explanation: In the northern hemisphere the surface wind is usually aligned a few degrees left of the wind aloft (due to friction partially reducing the Coriolis effect). In strong winds a gust temporarily increasing the surface wind will also bring about veering (clockwise directional change) due to the wind aligning more closely with the wind aloft. Therefore if an aircraft making an approach with a crosswind from the left encounters a gust the crosswind component will not greatly change - the veering offsetting the increased wind speed.

Conversely, a crosswind from the right will be trickier - the crosswind component will be increased by both of these factors: wind speed and veering. Other factors being equal, pilots making crosswind landings in the northern hemisphere will find crosswinds from the right more difficult than those from the left. In the southern hemisphere of course the opposite is true.

bean
8th Mar 2022, 12:58
https://youtu.be/kpiPvOjh3CM
Superb 1 hour vid of Belfast ops by Heavylift in 2001.
Interestingly, in one shot, we see the mach meter!!😉

Meikleour
8th Mar 2022, 13:35
Just as well the Vibrator never ventured into the non-equatorial Southern hemisphere! Crosswind landings would have been trickier!

Explanation: In the northern hemisphere the surface wind is usually aligned a few degrees left of the wind aloft (due to friction partially reducing the Coriolis effect). In strong winds a gust temporarily increasing the surface wind will also bring about veering (clockwise directional change) due to the wind aligning more closely with the wind aloft. Therefore if an aircraft making an approach with a crosswind from the left encounters a gust the crosswind component will not greatly change - the veering offsetting the increased wind speed.
hence the swing
Conversely, a crosswind from the right will be trickier - the crosswind component will be increased by both of these factors: wind speed and veering. Other factors being equal, pilots making crosswind landings in the northern hemisphere will find crosswinds from the right more difficult than those from the left. In the southern hemisphere of course the opposite is true.


Nope - the yaw occured even on calm wind days!!

With counterclockwise rotating props there is a left rudder component needed to counter the inherent swing to starboard. When the throttles are closed the flight idle blade pitch severely reduced the rudder and fin authority hence the yaw to port.

Discorde
8th Mar 2022, 14:31
Hi Meikleour

Where did the quoted 'hence the swing' come from? It wasn't in my post! :)

Summary: theoretical Vanguard landing in crosswinds in northern hemisphere: trickier right crosswind mitigated by left yaw effect described earlier. Southern hemisphere: trickier left crosswind exacerbated by yaw effect.

Discorde
8th Mar 2022, 14:38
Also: the rudder when counteracting the yaw from the engines (which varied in accordance with power setting) was acting in a 'free stream' airflow - not greatly affected by the propwash itself, which meant that (contd. p94)

Meikleour
8th Mar 2022, 15:41
Discorde: Hi, I think we both agree that a) throttle closure resulted in a yaw to port and b) that your Coriolis Effect also applies but I was trying to get to the source of the yaw swing in the first place as described by Scotbill.
I think it is difficult to argue that the rudder was always acting "in a free stream airflow" when every power change needed a rudder/rudder trim input! Thus for every given thrust there was a compensating rudder position. Removing the aerodynamic balance suddenly with the props blanking much of the airflow removes the initial required rudder moment hence the swing (my quote) Remember how on take-off with full power and slow speed left nosewheel tiller was required because of the rotational airflow on the fin until the rudder became effective.

Discorde
8th Mar 2022, 16:26
Hi Meikleour

We need an aerodynamics expert (which I'm definitely not) to sort this one out! I seem to recall that there are several reasons for variable engine power causing yaw changes, which rudder inputs oppose. On a single-engined aircraft one of the causes is spiral propwash past the fin-rudder but of course that doesn't apply to a multi with wing-mounted engines. Or does it? I wish I could remember . . . :)

brakedwell
8th Mar 2022, 20:01
As a comparison the Britannia performance figures are interesting.

General characteristics

Crew: 4–7
Capacity: 139 passengers (coach class)[84] (https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-Barnes_p360-89)
Length: 124 ft 3 in (37.87 m)
Wingspan: 142 ft 3 in (43.36 m)
Height: 37 ft 6 in (11.43 m)
Wing area: 2,075 sq ft (192.8 m2)
Airfoil (https://en.wikipedia.org/wiki/Airfoil): root: NACA 25017 (https://en.wikipedia.org/wiki/NACA_airfoil); tip: NACA 4413 (https://en.wikipedia.org/wiki/NACA_airfoil)[85] (https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-Selig-90)
Empty weight: 86,400 lb (39,190 kg) [84] (https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-Barnes_p360-89)
Max takeoff weight: 185,000 lb (83,915 kg)
Powerplant: 4 ◊ Bristol Proteus 765 (https://en.wikipedia.org/wiki/Bristol_Proteus_765) turboprop (https://en.wikipedia.org/wiki/Turboprop) engines, 4,450 shp (3,320 kW) each equivalent
Propellers: 4-bladed

Performance

Maximum speed: 397 mph (639 km/h, 345 kn) [86] (https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-Donald_p207-91)
Cruise speed: 357 mph (575 km/h, 310 kn) at 22,000 ft (6,706 m)
Range: 4,430 mi (7,130 km, 3,850 nmi)
Service ceiling: 24,000 ft (7,300 m) [87] (https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-Angelucci_p316-92)



Specifications (Type 952)Data from Vickers Aircraft since 1908[33] (https://en.wikipedia.org/wiki/Vickers_Vanguard#cite_note-andrewmorg_461-33)

General characteristics


Crew: 3
Capacity: 139 passengers
Length: 122 ft 10+1⁄2 in (37.452 m)
Wingspan: 118 ft 0 in (35.97 m)
Height: 34 ft 11 in (10.64 m)
Wing area: 1,527 sq ft (141.9 m2)
Empty weight: 85,000 lb (38,555 kg)
Gross weight: 141,000 lb (63,957 kg)
Powerplant: 4 ◊ Rolls-Royce Tyne (https://en.wikipedia.org/wiki/Rolls-Royce_Tyne) RTy.11 Mk 512 turboprops (https://en.wikipedia.org/wiki/Turboprop), 5,545 shp (4,135 kW) each (eshp)

Performance


Cruise speed: 422 mph (679 km/h, 367 kn) at 15,000 ft (4,600 m) (high speed cruise)[34] (https://en.wikipedia.org/wiki/Vickers_Vanguard#cite_note-basicp62-3-34)
Range: 1,830 mi (2,950 km, 1,590 nmi) with maximum payload

bean
9th Mar 2022, 09:46
Yep, the Vanguard was bloody fast!
Horses for courses compared to the Brit

Discorde
9th Mar 2022, 10:01
https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/409x505/vang_7_cb33309657acc9f57f6e8ded3c146725eeecd59a.jpg
More on the propwash/ yaw subject (or propwash/ yawn, some of you might say):

When the engines are producing thrust each engine is generating a spiral airflow, with the upper prop blades generating an overall lateral flow in one direction (right to left in the case of the Vanguard/ Tyne config) and the lower blades the opposite direction. The upper lateral flow will clearly impinge on the right rear fuselage and tail more so than the lower flow, imparting a yawing motion (to the right on the Vanguard), requiring a left rudder input to cancel.

When reduced to flight idle thrust the lateral flow from the props will disappear, meaning that the left rudder input countering the approach thrust throttle setting will now cause a yaw to the left, as Scotbill and Meikleour described.

Another factor (contd. p94)

bean
9th Mar 2022, 11:12
My memory wasn't playing tricks on me. Merchantman at Liverpool, 1995:

nZWl2zFY5-E

Interesting to note that, as well as No 3 being started first as per my recollection (9:00), taxy in after landing was on the outers only (1:30).
Your recollections are very wrong as far as BEA Vanguards are concerned. The BEA Vanguard operating a Jersey service in this clip already has number 4 in low ground idle and number 3 just starting
on the taxy in, 2 and 3 are idling certainly but, i never saw a BEA Vanguard shutting engines down during taxy
https://youtu.be/G7tVSFkoEX0

Meikleour
9th Mar 2022, 11:41
Great graphics Discorde!!

D P Davies ( aka HTBJs ) in his radio talks makes mention of an "along wing airflow" on four engined prop aircraft which invariably leads to some nasty stalling characteristics, hence the admonishment with the Vanguard to "not progress the stall beyond the initial buffet". Ron Gillman in his excellent book Croydon to Concord describes such an incident and probably explains why the subject airframe never seemed to fly "true" afterwards.