de Havilland Mosquito

I understood the latter part, i.e. the US government did not want the supercharger technology supplied to Britain, another example of this embargo was the Bell Airacobra being supplied without blower to the RAF.

And another thing, apart from a few prototypes, none of the Airacobras were fitted with turbochargers, whether in US or RAF service. The original specification was changed before the plane entered production, possibly due to installation problems with the engine-aft layout. The Allison engines were supercharged of course though, but the lack of turbocharging was one reason for this plane's poor high altitude performance.

Slightly o/t(!) DCN mentioned pprune forum- I go on there about once a week just to see who is fighting who! A frequently good read but, , damn, those "professional pilots" are an argumentative bunch!



Attack attack attackkkkkkkkkk..........

Slightly o/t(!) DCN mentioned pprune forum- I go on there about once a week just to see who is fighting who! A frequently good read but, , damn, those "professional pilots" are an argumentative bunch!



Attack attack attackkkkkkkkkk..........

Frustrated fighter jocks ...

Speaking of which, come back P11, we still love you even if you have defected to the Middle Kingdom ...

You are absolutely right about Pprune. Often fascinating, often deeply worrying that aircrew can be so competitively infantile. My No 2 child is a professional pilot and he wouldn't dream of participating there.

DCN

633 Squadron anyone?

Speaking of "Competitively infantile", I had not intended that my reference to the P38 be limited to just those ordered by the RAF or operated by the RAF-I meant ANY P38.
To get a broader viewpoint I googled "P38 vs Mosquito" and this is some of the discussions I found:
http://warships1disc...com/topic/10028

http://www.ww2aircra...squito-233.html

http://www.pistonhea...a...mp;d=0&nmt=

Not conclusive but interesting discussions if you care...

633 Squadron anyone?

Edited by JacnGille, 13 August 2012 - 02:17.

For a different slant on the Mosquito's versatility I would recommend a look at this - http://www.pprune.or...mosquitoes.html - covering the ball-bearing/passenger-on-oxygen-in-bomb bay BOAC flights from Scotland to Sweden and back. The best of British - lateral-thinking, brave...and sneaky...

DCN

I spent a week at the School of Military Engineering in Chatham, Kent, learning to survey with some of their advanced equipment, and they told us that during the war, unarmed planes were flown into Switzerland to pick up Wild survey equipment. Was that also a BOAC venture?

Continuing this OT diversion, the level of integrity you want in aviation, even in military aviation in wartime, is much greater than you'd need in those boats and cars.
To reverse an Allison V1710 you need a couple of left-handed camshafts and then either left-handed versions of oil pumps, fuel pumps, coolant pumps, supercharger, magnetos, starter and generator or else different drive gearing for each, arranged to do what the idler in the prop reduction 'box would do better.

Not being up with what they used on those geared props I dont know if it was simple or hard to make it run in reverse. On the grand scale of things making a simple engine run backwards is not that hard, pumps etc are very simple, like wise starters etc. But some of those complex radials are a no way!
But counter wise screws does make a lot of sense from a stability factor.
What do they do on modern twin engined planes?

As a young 55 year old. I have to say 633 squadron is one of my favourite films.

Not being up with what they used on those geared props I dont know if it was simple or hard to make it run in reverse.

No idea if this is true or not, but I was once told by an ex-pilot, that on the Allisons used in the P-38, reversing the engine didn't require much more than a change of firing order. That can't be right can it?

Not being up with what they used on those geared props I dont know if it was simple or hard to make it run in reverse. On the grand scale of things making a simple engine run backwards is not that hard, pumps etc are very simple, like wise starters etc. But some of those complex radials are a no way!
But counter wise screws does make a lot of sense from a stability factor.
What do they do on modern twin engined planes?

As I wrote, there are a lot of components that would have to be redesigned to run backwards. I didn't say it was difficult, but that it doubles the parts inventory and therefore adds expence and problems in time of war. What I didn't even begin to comment on was such details as changing from righthand to lefthand threads for some critically important nuts to still be self-tightening, oil return scrolls redesigned to not pump oil overboard, lefthanded tachometer drive or instrument and much more.
The prop reduction on the V1710, as with most in-line engines, was a simple pair of spur gears so the prop and engine rotate in opposite directions. It is a straightforward bit of redesign to add an idler pinion to get the prop rotating in the same direction as the engine.
Here's a cutaway from page 233 of the cutaway thread:


There are very few modern twin-propellor aeroplanes and those that there are are not in the same power/weight league as these aeroplanes so I doubt they bother with contra-rotation. Since most have gas turbine engines it would certainly be done by gearing, if at all - even the non-technical must see that a gas turbine cannot easily be made to run backwards.

No idea if this is true or not, but I was once told by an ex-pilot, that on the Allisons used in the P-38, reversing the engine didn't require much more than a change of firing order. That can't be right can it?

ETA no of course it's wrong. Just consider what you'd have to do to a single cylinder four-stroke engine to get reverse rotation, before you think of ancilliaries, etc that I've been banging on about

Edited by Allan Lupton, 13 August 2012 - 07:53.

ETA no of course it's wrong. Just consider what you'd have to do to a single cylinder four-stroke engine to get reverse rotation, before you think of ancilliaries, etc that I've been banging on about

I'm not an engine man, and I'll admit straight away that this next bit comes from Wikipedia, but interesting all the same.

"Another feature of the V-1710 design was its ability to turn the output shaft either clockwise or counter-clockwise by assembling the engine with the crankshaft turned end-for-end, by installing an idler gear in the drive train to the supercharger and accessories and by installing a starter turning the proper direction. There was no need to re-arrange the ignition wiring, firing order, or the oil and Glycol circuits to accommodate the direction of rotation."

Even more interesting, it appears that there was an airship version of the V-1710 which could be stopped in flight, and restarted seconds later in the opposite direction.

....as a matter of semantics do we mean contra when talking about counter?

....as a matter of semantics do we mean contra when talking about counter?

I'm not sure - I followed the precedent of the first mention.
A Fairey Gannet had two propellers rotating in different directions about the same axis. Each powered by a separate engine. Those propellors are definitely contra-rotating. The Shackleton had four engines each powering two propellers rotating in different directions, I have seen it described as ".. the first British four-engined aircraft with contra-rotating propellers.
I would say that with a twin and its two propellers not mounted on the same axis, perhaps "counter-rotating" should be the correct usage.

Edited by D-Type, 22 April 2022 - 16:08.

I'm not an engine man, and I'll admit straight away that this next bit comes from Wikipedia, but interesting all the same.

"Another feature of the V-1710 design was its ability to turn the output shaft either clockwise or counter-clockwise by assembling the engine with the crankshaft turned end-for-end, by installing an idler gear in the drive train to the supercharger and accessories and by installing a starter turning the proper direction. There was no need to re-arrange the ignition wiring, firing order, or the oil and Glycol circuits to accommodate the direction of rotation."

Even more interesting, it appears that there was an airship version of the V-1710 which could be stopped in flight, and restarted seconds later in the opposite direction.

I cannot understand that Wikipedia claim. Turning a symmetrical six-throw crank end for end achieves nothing and we are asked to assume the prop drive and accessories drive splines are the same which is unlikely bearing in mind the power expected through them. Look at that cutaway and show me where that one idler that reverses all the accessories drives goes. . .
Wikipedia has a deservedly bad reputation for unsupported statements and there is little we can do about it. I've corrected statements in entries, only to have them de-corrected instantly without evidence for the provenence. The list of edits for the V1710 page is temendous.

The V1710B airship version was unsupercharged and was designed well before the P38 engines and was abandoned in 1935. to reverse it involved a shifting mechanism for camshafts and much more.

I cannot understand that Wikipedia claim.

Probably written by the same Australian ex-P38 pilot who told me you could reverse the engine just by swapping the plug leads...

I gather that Kermit Weeks is still hopeful that his Mossie will be flying again, having last flown in 1989.

I just received a reply frpm Fantasy of Flight restoration specialist Paul Stecewycz about 2 of their aircraft...."Lancaster is a disassembled project in storage and the Mosquito is on static display at the EAA Museum in Oshkosh."

For a forum about aeroplanes as good as this, try this:

http://forum.keypubl...display.php?f=4

Just as impressive line-up of participiants as here - ex-servicemen, pilots, anoraks and historians. Great discussions - and politics are allowed! When war is on the agenda, hardly avoidable, but often very thoughtprovoking.

Regarding opposite direction rotating props - the military Airbus A400M uses gears, in order to make the spares inventory as small as possible and provide greater lift:

"The pair of propellers on each wing of the A400M turn in opposite directions, with the tips of the propellers advancing from above towards the midpoint between the two engines. This is in contrast to the overwhelming majority of multi-engine propeller driven aircraft where all propellers on the same wing turn in the same direction. The counter-rotation is achieved by the use of a gearbox fitted to two of the engines, and only the propeller turns the opposite direction; all four engines are identical and turn in the same direction which eliminates the need to have two different "handed" engines on stock for the same aircraft, which simplifies maintenance and supply costs. This configuration, dubbed DBE (Down Between Engines), allows the aircraft to produce more lift and lessens the torque and prop wash on each wing. It also reduces yaw in the event of an outboard engine failure."

From wikipedia: http://en.wikipedia....bus_A400M_Atlas


Regards

Jon

For a forum about aeroplanes as good as this, try this:

http://forum.keypubl...display.php?f=4

Just as impressive line-up of participiants as here - ex-servicemen, pilots, anoraks and historians. Great discussions - and politics are allowed! When war is on the agenda, hardly avoidable, but often very thoughtprovoking.

Thanks

"... The counter-rotation is achieved by the use of a gearbox fitted to two of the engines, ...

Presumably a different gearbox? The engines have a reduction gearbox, so either the gearbox itself is different, or there is an 'add-on' of some form?

Thanks


Presumably a different gearbox? The engines have a reduction gearbox, so either the gearbox itself is different, or there is an 'add-on' of some form?

An extra set of gears I suppose.


Regards

Jon

Regarding opposite direction rotating props - the military Airbus A400M uses gears, in order to make the spares inventory as small as possible and provide greater lift:

"The pair of propellers on each wing of the A400M turn in opposite directions, with the tips of the propellers advancing from above towards the midpoint between the two engines. This is in contrast to the overwhelming majority of multi-engine propeller driven aircraft where all propellers on the same wing turn in the same direction. The counter-rotation is achieved by the use of a gearbox fitted to two of the engines, and only the propeller turns the opposite direction; all four engines are identical and turn in the same direction which eliminates the need to have two different "handed" engines on stock for the same aircraft, which simplifies maintenance and supply costs. This configuration, dubbed DBE (Down Between Engines), allows the aircraft to produce more lift and lessens the torque and prop wash on each wing. It also reduces yaw in the event of an outboard engine failure."

That is another Wiki entry that makes little sense, particularly that last sentence. It was edited in on 12/12/09 by someone with just an IP address so no credentials can be established.
The engine uses an offset reduction gearbox anyway so without looking it up it seems likely that an added idler reverses the rotation.

In June 1992 I, along with a number of VSCC friends, was privileged to be invited to Hawarden airfield by Peter Henley, VSCC member and British Aerospace test pilot. He was also entrusted with piloting BAe's Mosquito at air shows and, as he was scheduled to do some testing prior to a forthcoming display, he asked if we would like to get a close-up view of this fabulous aircraft. It was a memorable experience and great to be a able to watch it at close quarters as Peter did some circuits, flying low and giving plentiful hand gestures out of the cockpit window. Peter retired a few years later and it was his successor who had the misfortune to be at the controls when it crashed at Barton air show in 1996.

Don't look too closely, and it could be Hawarden in 1943

A few more pics to follow.

Wing Commander Peter Henley makes ready

Thank you Alan. Those pictures are so achingly nostalgic.

In case Australian residents are not aware of the Mosquito under restoration (albeit not to flying condition) at Point Cook, this link may be of interest. But a warning... the text makes reference to chain saws. Aaargh! Quite nerve jangling!

Yes thanks Alan, not least for getting this thread back to its subject.
Nice photo of Peter, whom I haven't had contact with recently. In another life he is a VSCC member with a Derby Bentley and (I think) an Alvis.

An update from Auckland
http://www.theauckla...er2012/1506052/

I think my service life question has been answered by the 2 articles. The Point Cook one was worn out at 300 odd hours and the NZ one would suffer a lot of wear in 75 hours to the US.Though during the war probably not many got to those hours without being shot down, or fell down through lack of maintenance when there was never enough hours or planes.

Last night on SBS ONE in Australia they screened Death or Freedom - The Jericho Jailbreak with Martin Shaw etc. I was left with a few doubts about this raid. I am sure many will have an opinion.
However if you are in NZ and want to see the Mosquito fly next month then what better way to arrive.
http://rnzaf.proboar...mp;thread=16884

this appeared in today's Vancouver Sun-I hope it is not cropped to closely to read:



Uploaded with ImageShack.us

Edited by David Birchall, 02 September 2012 - 03:17.

this appeared in today's Vancouver Sun-I hope it is not cropped to closely to read:



Uploaded with ImageShack.us

Here is the uncropped version:
http://www.vancouver...8787/story.html

ZK-MOS has her C of A !
The attached page has photos of engine runs today.
http://rnzaf.proboar...d...707&page=36

Edited by Patrick Fletcher, 25 September 2012 - 11:56.

Great - a candidate for star guest at Goodwood?

ZK-MOS has her C of A !
The attached page has photos of engine runs today.
http://rnzaf.proboar...d...707&page=36

Wonderful news! Wonder if we'll ever see it in Europe?

If anyone is interested TVNZ aired some footage of the Mosquito project this week - available for view on line here.

(Sorry you have to sit through a short advertisement before the real thing starts).

Edited by Redneb, 26 September 2012 - 01:54.

First flight this morning from Ardmore, landing at Mangere with the Trojan chase in close formation .The ASI was u/s so the Trojan was able to guide calling airspeeds.
Has been up again this afternoon and maybe return to Ardmore.

Edited by Patrick Fletcher, 29 September 2012 - 08:10.

Good to see another one back in the air.

First flight this morning from Ardmore.

FANTASTIC!!
:up::up::up:

Nice group of photos on this link
http://rnzaf.proboar...d...7190&page=2

and here.
http://rnzaf.proboar...d...707&page=52

Edited by Patrick Fletcher, 29 September 2012 - 09:55.

TVNZ "Warbird flies again":
http://tvnz.co.nz/na...n-video-5108120

I cannot understand that Wikipedia claim. Turning a symmetrical six-throw crank end for end achieves nothing and we are asked to assume the prop drive and accessories drive splines are the same which is unlikely bearing in mind the power expected through them. Look at that cutaway and show me where that one idler that reverses all the accessories drives goes. . .

I suppose turning the crank end for end is so that oil flows and so forth work properly. The V-1710 had end for end lubrication - that is the lubrication for the main bearings, big ends and gudgeon pins was fed through the crankshaft and out into the bearings, compared with most early versions of the Merlin where the oil was first pumped into the main bearings then transferred to the others.

The camshafts on the V-1710 also had to be reversed - to maintain the proper timing.

As for the idler gear, Take a look at these:

Allison V-1710 Gear Train for Right-Hand Rotating Engines

The gear that gets changed is labelled H.

Allison V-1710 Gear Train for Left-Hand Rotating Engines

As you can see gear H has been changed from a continuous gear to one with a gap in the centre. Idler K has moved around from doing not much of anything to mesh with H and T.

The Merlin system does seem simpler, as it does not require a wholesale rebuilding of the engine. But unless your Merlin has the correct reduction casing with mountings for the idler gear and shaft and you have the idler gear and shaft then the Merlin can't be reversed. Which was not a problem for most Merlin types.

I think my service life question has been answered by the 2 articles. The Point Cook one was worn out at 300 odd hours and the NZ one would suffer a lot of wear in 75 hours to the US.Though during the war probably not many got to those hours without being shot down, or fell down through lack of maintenance when there was never enough hours or planes.

The record number of sorties for a bomber Mosquito (actually, for all allied bombers) was 213 by Mosquito B.IX LR503.

LR503 was an Oboe equipped pathfinder. The use of Oboe required the bomber to follow an arc a certain distance from a base station, until it received a signal from a second station, at which point the markers would be dropped. The Germans were well aware of this technique and could even predict where the raid would be based on the signals from the two stations.

LR503 crashed in Canada at the end of the war during a demonstration for a war bonds drive.

http://www.vintagewi...or-Freddie.aspx

Edited by Wuzak, 29 September 2012 - 10:34.

W4050, the Mosquito prototype, is also undergoing restoration at the moment.

Not sure which configuration they will be restoring it to - maybe with Merlin two stage engines? The colour scheme will be camouflage on the upper surfaces and trainer yellow on the lower surfaces.

W4050 sits in the hangar out the back of Salisbury Hall, as part of the de Havilland Museum. It, of course, will never fly again.

Continuing this technical digression on Allison engines, an end-fed crankshaft lubrication system isn't rotation-sensitive. What does happen is that the end remote from the feed can get starved but there would be no benefit in the claimed swapping of the shaft end-for-end.
The gear diagrams are quite similar to (and a bit clearer than) one I have which comes from the Allison Service School Handbook. What is not clear on either is why there are two apparantly equal-sized wheels on the crankshaft. The idler Wuzak refers to keeps the supercharger, camshafts and lots of accessories going the right way when the crank is reversed. However there has to be a change of alignment in the fuel pump drive bevel because left and right-hand starters must have been used (you can see the direction of the dogs at No 10 changes).

Just to point out the obvious (to me), as early V1710 3:2 prop reduction used an internal driven gear and that would be quite difficult to change rotation direction, one is tempted to think that the reversed engine was seen as being in some way easier.
However by the time the P38 needed its V1710 engines, the model F with a spur gear reduction box had been introduced anyway as the original was never really satisfactory.

Edited by Allan Lupton, 29 September 2012 - 13:53.

W4050, the Mosquito prototype, is also undergoing restoration at the moment.

Not sure which configuration they will be restoring it to - maybe with Merlin two stage engines? The colour scheme will be camouflage on the upper surfaces and trainer yellow on the lower surfaces.

W4050 sits in the hangar out the back of Salisbury Hall, as part of the de Havilland Museum. It, of course, will never fly again.

I don't want to sound too much of a misery-guts, but why bother? If the aircraft is never going to fly or even to taxi, and only be a static display, it doesn't need engines at all. At most it needs wooden replicas of what can be seen from the outside. Even if it is to be displayed with engine cowlings off, the engines need no internals. Surely the money could be better spent elsewhere - keeping flying aircraft flying or restoring badly deteriorated aircraft to static display level.

As the prototype is just that and has not been a flying aeroplane for a very long time I doubt they would fit airworthy engines and certainly not two-stage supercharged jobs.
That it exists at all is due to the direct disobedience of Bill Baird who was told "Burn the damn thing, it's a nuisance!" by the Works Director, but managed to hide it until the owner of Salisbury Hall, Walter Goldsmith, could get a hangar to put it in.

I don't want to sound too much of a misery-guts, but why bother? If the aircraft is never going to fly or even to taxi, and only be a static display, it doesn't need engines at all. At most it needs wooden replicas of what can be seen from the outside. Even if it is to be displayed with engine cowlings off, the engines need no internals. Surely the money could be better spent elsewhere - keeping flying aircraft flying or restoring badly deteriorated aircraft to static display level.

I don't know if they will fit actual working engines.

They will rebuild it in the configuration it was in using 2 stage Merlins - ie longer cowl, intercooler radiator ducts below the spinners, etc.

The Mosquito FB.26 makes its airshow debut.

http://www.photofini...-war-2-aircraft