How do you sync Lanc engines?

[gratlump]

This is probably off topic but I was watching Channel 4 last night about the Lancaster. What a great follow on from the Spitfire the previous week. Whilst listening to the commentary they mentioned the synchronising of the Merlin engines prior to takeoff. Ok, I can have a pretty good educated guess of what that means and how it might be achieved but can anybody tell be definitively.

Many thanks.. .Graham.

[New Bloke]

I can't see why (unless the nieghbours object) anyone would synch the engines on the ground prior to T/O. I would have thought that they would be done once established in the cruise and then a crude synch by RPM gauge followed by fine tuning by ear.

Unfortunatly I have only been in one once (Biggin Hill BoB display 1969/70) and that was a static display so I may well be talking total bolls.

[Vfrpilotpb]

New Bloke,

About spot on! :)

[Jeremy Cooke]

My dear old Dad ...still going strong at 79...was a Lanc pilot and apparently they used full chat for T.O. and climb (of course - one can only imagine the performance or lack of it with a full fuel and bomb load!!) in the cruise they "synched" the engines by adjusting the props until they "strobed" (for want of a better word!) stationary as viewed from the cockpit when looking at them in line. I've just read this and it isn't that clear is it? But that's how they did it....

[DB6]

From an ex-OC BBMF who flew the Lanc and who is my flight commander at work (I asked him this morning): using RPM levers in the cruise, working from no.1 to no.4 engines, by listening for the harmonics. Apparently when all is nice and set up the RPM and throttle levers are all over the quadrants since the engines are all a bit different (N.B. this is the current BBMF Lanc, I imagine factory-fresh ones were a bit different).

[gratlump]

Thanks for the replies guys.

Graham Perkins.

[Vfrpilotpb]

DB6,. .I would imagine that the BBMF Lanc is a better piece of kit from the engineering point of view than most WW2 bomber flyers ever used, apart from its age!

[Centaurus]

I may be able to help on this one as I was a QFI on Lincolns.. . When lined up and ready for brakes release, the pilot opens the throttles to zero boost (equivalent to static manifold pressure of 30 inches). That is to ensure all engines are stabilized. Propeller synchronization as such does not come into it yet. If all OK, the brake lever is released and throttles are opened with the port throttles leading the others by an inch or so (prevents early yaw) until rudders become effective around 15 seconds later when all four throttles are set to the desired boost. We used +12 pounds per square inch boost for normal take off which could be increased to +18 in an emergency or if runway length was limiting - except it beat the hell out of the engines. The full fine pitch gave 3000rpm at take off power. . .Before take off checks included confirming that the rear gun turret was aligned and not traversed one way or the other. If not aligned it could cause a marked yaw as speed increased down the runway.

Comfortably into the climb around 500 feet, power was reduced to +9 and 2650 rpm, (and flaps retracted from one quarter down to the fully up position)-and that is where we would now synchronize the props for the first time because an out-of-beat synchronization noise could be very annoying.

To synchronize, we would first ensure that all four rpm gauges were on 2650 rpm, then listen for any irregular beat. This was usually due to one or two props not showing 2650 exactly. . .Having done that, one would look outside along the line of both starboard and both port engines and note if the props were strobing (it looked like a slow moving shadow through the prop arcs).

If the shadow was there (and this would be accompanied by a gentle off-beat noise), then one would adjust either the inboard or outboard pitch lever by a few rpm until the strobing stopped and the noise settled down to a steady roar. Then a re-check of the RPM gauges to ensure 2650 was being maintained. Repeat as required for all boost and RPM changes from climb to cruise power to descent power etc. Sounds complicated but the whole procedure could be completed within 20 seconds or so. I do not recall any undue mis-alignment between the four pitch and throttle levers in fact most times they were remarkably even. For info, I had around 25 real engine failures during my 3000 hours on the Lincoln. Several of these were shortly after lift off. The Rolls Royce Mk 86 and Mk 102 engines did not like the tropics.. .Hope this helps.

[ 25 January 2002: Message edited by: Centaurus ]</p>

[oxeone]

Well done Centaurus!!!. .That's just what Daddy said, but he didn't give me any numbers !!. .Incidently he was "on" Yorks after the war and he would agree wholeheartedly with your comments about Merlins not liking the Tropics!

[DB6]

Vfr, airframe-wise yes, but they don't have many Merlin engines so have to mix and match. I think the Lanc, the Hurricanes and the Mk2 Spit share the same Merlins and I seem to remember that they had to ground one of the Hurris (I think) so they could nick its engine to keep the Lanc flying. . .I went to a talk on the Merlin and Griffon by an ex-Rolls-Royce engineer a couple of years ago and at that time there was no-one in the UK that could service Merlins, they had to be sent to America (I believe this was due to CAA regulation, not engineer availabilty).

[clive noel]

DB6, the BBMF Lancs airframe is indeed in magnificent condition. I was an engineer involved in her overhaul down at RAF St Athan in 95/6 when her main spar was replaced (the BAe guys up at Chadderton did a marvellous job manufacturing a replacement spar by jigging the centre section fuselage, extracting the old spar and having made an exact replica (this could not be done from original engineering drawings as every spar built was slightly different due to the constraints of manufaturing at that time) fitting it back into the jigged fuselage section). When we rolled her out for engine runs at the end of the project she looked absolutely stunning and sounded magnificent. Even now when I see the lucky BBMF crews putting her through her paces it still brings a lump to my throat to think that in my own small way I have contributed to keeping her flying for further generations to see. My 3 yearold son recognises its shape in the sky instantly!

[DB6]

Canoe, I'm sure other people have different opinions but I personally think it's the best-spent part of the defence budget. . .I'm sure I speak for a lot of the people who read this forum when I say thanks for keeping it going.

[Vfrpilotpb]

I wholehartedly agree DB6, it would be a very , very sad day for the Aviation world, if some pimple headed, politically correct department of any part of the armed forces decided to hive of any of the BBMF aircraft, its just a pity, that they did that with the Shacks, and a further pity that the Griffon would not fit the Lanc! <img src="smile.gif" border="0">

[clive noel]

Vfr it really is a shame that the Griffon does not fit the Lanc as maybe then they would leave the engine in "my Spitfire" long enough for it to get some air time! In explanation: my involvement in the Lancaster respar project came about because of the work I had carried out the previous year on an ex-Gate Guardian MkIX Spitfire - MK356. Due to the amount of flying that the BBMF are involved with during the display seasons it was decided that another fighter was needed to compliment the flight. As we know there are no more Hurricanes (in fact at the time that this request was made the BBMF Hurricane that had crashed and burnt was still in the process of being refurbished by a civilian company) and so close examination of the Spitfires held in storage in the RAF St.Athan 'museum'was carried out. At first it did not look good, the better of the airframes were some of the younger PR role aircraft but these did not fit the bill for the BBMF. The best of the rest was MK356 which had finished it's days on Gate Guard duty. It was a MkIX and would have been ideal had it not been for one annoying problem. This aircraft had been used as an extra during the filming of the The Battle of Britain and on one particularly windy day of the filming the aircraft was needed in a scene but the wind was causing the aircraft to rock and sway and the director wanted the aircraft to be steady in the shot. He asked the liason Officer working on the project if he could picket the aircraft in such a way as to prevent it moving around but so that the restraints would not be 'in shot'! The guy came up with a scheme that involved dilling through both wings, fitting 'U' bolts under the wings and tieing these off to ground spikes hidden by the grass. Not a bad idea really except that he drilled straight through both the wing spars!! Therefore rendering the wings totally unusable. One of the other aircraft in the 'museum' was an extremely scabby MkXV. The XV was in escence just a modified IX and so the decision was made to combine the two. The rest as they say is history although replacing every rivet on a Spitfire and dimpling new skins is something that I look back on with mixed emotions. After all the months of hard work and dedication an engine was finally acquired for her and she flew - bloody magical. Which takes me back to my original point - once she had been handed over to the BBMF the Lanc starting eating engines quicker than they could fix them and so MK356s Merlin seems to be on constant standby for her big sister and she is very rarely flown. I'm sure she'll have her day again though!

[Man-on-the-fence]

Canoe. .Interesting story,I saw MK356 when they were doing the initial survey at Abingdon, I haven seen her fly yet.

Which MkXV did they use and what happened to it??

. .PS Thanks for all your work on the Lanc, it really is appreciated