What is wrong with the Merlin engine?

[KelvinD]

A very, very long time after its introduction, the powers that be have decided there are issues with the Merlin engine, apparently serious enough to ground the BBMf fleet.
Engine issue grounds Battle of Britain Memorial Flight planes - BBC News (http://www.bbc.co.uk/news/uk-england-lincolnshire-40957271)

[DaveReidUK]

Piston engines that old go u/s all the time.

A more likely explanation for the grounding is that an issue has been found with the engine on one of the Spits (or maybe the Hurricane/Lanc) that's considered potentially serious enough to merit an immediate check of the rest of the fleet.

If the check involves complete stripping of the engine and/or precautionary replacement of a part that has to be specially manufactured then it's almost inevitable that the fleet will be grounded for a while.

[Mr Mac]

Unfortunate time of year for it to happen given the number of events they are booked into. That DC3 they have could be very busy ! Does this also cause an issue with the "Packard Merlins" on the Mustangs which are over here from US currently as well ?

[Oldlae]

During my apprenticeship at Halton we covered the Merlin engine. All the examples we practised on were Packard engines, built under licence. This begs the question, are the Merlins in the BBMF Packard Merlins or RR Merlins?

[ciderman]

Wasn't it camshafts that caused the Hurricane crash many years ago? I think they are like hen's teeth. Friend of mine broke his leg trying to force land it.

[JEM60]

Brilliant forced landing. Not a lot of fun trying to land something with a serious fire. A lot of admiration for your friend.

[ciderman]

Thanks Jem. He's not too good at the moment so I am sure all his pals will wish him all the best.

[treadigraph]

This begs the question, are the Merlins in the BBMF Packard Merlins or RR Merlins?

The Lancaster, Hurricanes, MkII, MkV and MkIX Spitfires should all have RR Merlins, the MkXVI should be a Packard.

Ciderman, best to your mate as well. I seem to recall his next outing in a Hurricane, a tech problem during the display led to a very hurried and skilled landing; happily with a much better outcome for him, the aeroplane and the heart rates of those of us watching!

[The AvgasDinosaur]

Is it just BBMFs Merlins that have been grounded ? Or have all RR built Merlins been grounded in the U.K. ?
Does it apply to civil Merlins too?
Thanks for your time and trouble.

[treadigraph]

Just BBMF at the moment...

[The AvgasDinosaur]

Is it therefore a question about servicing/maintenance rather than component integrity?
Thanks for your prompt reply treadigraph.

[VictorGolf]

Post elsewhere suggests metal in the oil from one of the Hurricanes but I guess that isn't confirmed.

[megan]

The Lancaster, Hurricanes, MkII, MkV and MkIX Spitfires should all have RR Merlins, the MkXVI should be a Packard.The Lancaster I/III during war time was produced with the RR Dash 22, or Packard Dash 28/Dash 224. Canadian built Hurricanes similarly had Packard (Dash 29).

It was said a Lancaster you were flying could have each engine produced by a different manufacturer - RR, Packard, Ford, Continental.

What manufacturer/version the BBMF airframes are actually fitted with would require someone in the know. Restored Spitfires have been fitted with commercial versions of the engine. Interestingly the original Buchon was fitted with a commercial version of the Merlin.

[treadigraph]

I should imagine there are quite a few aircraft flying with Merlins that are not entirely appropriate to the Mark but what the hell!

I believe one of the two-seat MkIXs in the UK has a Packard so technically it should be a TR.XVI I guess.

I seem to remember that the BBMF's Griffon Spitfires have Shackleton engines with the contra-prop gearbox replaced.

Keep 'em flying! :ok:

[Oldlae]

Moderator.

Surely this should be merged with BBMF Grounded in Military Aviation.

[megan]

treadigraph, I trawled through the records for British registered Merlin/Griffon powered aircraft to see what Mark engines were fitted. Some records didn't include Mark, so I ignored. Lancaster was one of those. Sent the list as a PM as it doesn't seem like the attachment process will display it here.

[treadigraph]

BBMF Spitfire XIX PS915 performing at nearby Biggin as I type!

Thanks Megan, there seem to be three TR.IXs with Packards, a PR.XI and two XVIs. The Griffon RG 30 SM-S are the modified Shackleton engines in the XIV and XIX owned by Rolls Royce.

The Spitfires with no engine types listed are all still under restoration.

Interestingly, P-51D G-SHWN is listed as having a RR Merlin rather than a Packard...

Of the three Lancasters on the register, G-LANC is preserved at Duxford, G-BCOH is in bits at Kermit Weeke's place and G-ASXX has four newly rebuilt Merlins ready for when she becomes airworthy - hopefully!

PS915 has returned to Southend for the display there.

[Centaurus]

The Lancaster I/III during war time was produced with the RR Dash 22, or Packard Dash 28/Dash 224. Canadian built Hurricanes similarly had Packard (Dash 29).

It was said a Lancaster you were flying could have each engine produced by a different manufacturer - RR, Packard, Ford, Continental.
.

During WW2 there were several reports of uncommanded feathering of all four engines in Lancasters that resulted in the loss of crews. In April 1996, I talked to a Lancaster crew member Chris Jarrett who was in a Lancaster that lost all four engines after the pilot ordered his flight engineer to feather the propeller of an engine that failed in flight. The crew member managed to bale out through the front hatch and was later captured and spent the remaining war days as a POW.

Circa 1958 I experienced this phenomena on one occasion in a Lincoln Mk 31 (RAAF) during an engine run as part of a propeller change. On feathering a propeller as part of the testing required before removal of a propeller during scheduled servicing, the adjacent engine experienced an uncommanded feathering. In other words two propellers feathered instantaneously by the press of one feathering button. The fault was traced to a short circuit between the day/night switch on each of the feathering buttons and its protective metal cage.

The book "Flight of the Halifax" by Captain Geoff Wilkner, who was a ferry pilot during WW2, describes his experience flying a Lancaster in England on a delivery flight. He was feathering each propeller one at a time en route Strathaven to Scampton when multiple uncommanded featherings occurred.
He later learnt that four Lancasters had crashed at different times and all the crews killed. Investigators found the airscrews in the feathered positions.

[megan]

G-SHWN is listed as having a RR Merlin rather than a PackardG-INFO lists it as having its proper Packard V-1650-7. A non anorak is still correct in saying its a RR Merlin I feel.

[Danny42C]

treadigraph and others,

This old puzzle in my log entries may deepen the confusion !

(20 Sqn, Valley):

1950 April 17...Spitfire IX .TD254
...........18...Spitfire IX .TB379
...........20...Spitfire XVI RW 351
...........27...Spitfire IX .TD254

......July 25...Spitfire XVI TD254

This was not queried either by Flight or Squadron Commander on the Monthly Summaries. As I remarked earlier in "Pilot's Brevet in WWII" (Military Aviation Forum): "I would certainly have known the difference, or had it sharply pointed it out to me !"

All subsequent Spitfires were logged as XVIs. It would seem that nobody bothered with the difference any more.

Possibility: if a Merlin Spit were re-engined as a Packard Spit, would a IX turn into a XVI ?

(Just asking). Danny.

[megan]

Your answer Danny - from "Spitfire - The History" by Morgan & Shacklady.As production of the F Mk IX Spitfire quickened and Fighter Command squadrons were able to assess the qualities of the new mark, it became evident from combat reports that most interceptions were taking place at a lower level than previously encountered. The Commanding Officer of the Middle East fighter units requested that supplies of Spitfires be limited to the lower altitude examples and the production lines were hard put to meet demand. The final answer to this demand was the F Mk XVI, virtually a Mk IX airframe with the Rolls-Royce Packard Merlin engine.

The designation had not been applied just to differentiate between the UK built engine and the American. The latter unit did have minor fitments to the former and the F XVI designation was an aid to the ordering of spares. Apart from this both aircraft were virtually identical. The pilot notes cover the IX, XI & XVI with Merlin 61, 63, 66, 70 or 266. The only difference in the notes is the boost limits of the different engines.

I guess the short answer to yourif a Merlin Spit were re-engined as a Packard Spit, would a IX turn into a XVI ?would be no, not knowing what the "minor fitments" mentioned may have been, and the designation change to facilitate spares ordering.1950 April 17...Spitfire IX .TD254
...........18...Spitfire IX .TB379
...........20...Spitfire XVI RW 351
...........27...Spitfire IX .TD254

......July 25...Spitfire XVI TD254They were all XVI Danny.

RW351 XVIE CBAF VAHP 12-7-45 6MU 27-7 631S 28-11-47 C4R(S) 25-4-51
TB379 XVI 6MU 4-2-45 421S 22-3 631S 3-2-49 NES 14-13-54 sold H. Bath 1-5-56 (obvious date error re NES)
TD254 XVI 19MU 12-3-45 74S 341S 10-5 127S 17-5 322S 24-5 631S 8-12-48 AGT Gatwick refurb 24-6-51 NES 14-12 sold E. Smelt 13-6-56

Wonder if those sold are still extant.

TD254

http://www.raf-in-combat.com/wpsite/wp-content/uploads/edd/2015/09/tn_Spitfire-16-23.jpg

RW351

https://abpic.co.uk/pictures/full_size_0260/1391464-large.jpg

[treadigraph]

G-SHWN is listed as a Rolls Royce V-1650 - which presumably identifies it as a Packard; I suppose the CAA simply add the details as supplied by the registration applicant.

The obvious difference in the two pics is RW351 is a low back XVI and TD254 is a high back, wonder if TB379 was a high back?

None of them appear to be survivors but there seems to be the significant remains of an airframe or two reappearing each year so you never know.

[DaveReidUK]

I suppose the CAA simply add the details as supplied by the registration applicant.

Indeed so.

And, in the case of a type like the Spitfire that can accommodate various manufacturers and marks of the Merlin/V-1650/Griffon there is no guarantee, if an engine is swapped for another variant, that the registration details will be updated to reflect the change.

[Danny42C]

megan (#21) and DaveReidUK (#23),

Thanks for the info ! This extract from my Post on Military Aviation Forum; "Pilot's Brevet", Page 169, #3380, shows how it could happen:

"The bane of our lives was the Squadron Aircraft Inventory. You might suppose that an aircraft came (Stores-wise) as one complete unit. No such luck. First you had (say) a Spitfire XVI airframe number so-an-so. This came in under its unique Stores Reference. Then came a Merlin Mk. 266 engine serial number whatever, with its own Stores Ref. We're there now ? Not a bit of it ! As cherry on the cake, we also had 24 spark plugs (God knows what Stores Ref.) to account for. Why, of all the hundreds of parts in an aero engine, this one item should be singled out, is beyond me. Perhaps it was the easiest of all to take out and get lost.

If a complete aircraft came (raise Demand Voucher on Stores) or went (raise Return Voucher), it was relatively simple, although you had to be careful to list all the serial and reference numbers correctly, and not forget the plugs, and enter all the details of the copy Voucher in the Inventory when (if) it came back from Stores . But then there were engine changes, where only the engine details needed amendment, but the plugs had to booked-out and in like everything else. And these, IIRC, could be swapped (Exchange Voucher) from Stores when they got coked-up or whatever. And copy vouchers can easily get lost, or get entered up wrongly.

You'd need a clerk of saintly assiduity to keep up with this. We had a succession of National servicemen of very variable quality. The Inventory became a nightmare. On paper, we had twin engined Spitfires with an astronomical number of plugs, a single-engined Beaufighter with none at all, and - to cap it all - one whole Spitfire went missing (on paper, at least !) It reminded me of Burma, where rumour had it that a certain W/Cdr Chater had worked the system so well that he had at his disposal a personal Harvard and a Tiger Moth that no longer (officially) existed".

Danny.

[megan]

G-SHWN is listed as a Rolls Royce V-1650 - which presumably identifies it as a PackardAny engine identified as a V-1650 is a Packard, even though they are all V-1650 by configuration and capacity. Just the way they happen to be identified.he had at his disposal a personal Harvard and a Tiger Moth that no longer (officially) existedNothing changes Danny. In Vietnam the US Army had stringent rules as to what stocks were allowed to be held, of course never enough, so additional stocks were procured by various means - don't ask any questions. Trouble came when the high brass did their inspections, errant stores were loaded onto transports and drivers told to get lost and come back after.

CO of a US Army OV-1 unit was coming up for an inspection and went to the trouble of counting his aircraft on the flight line. One too many. In the bar an offer was made to some of our helo pilots to take it off his hands. Wasn't there, so perhaps beer talk, though the tale tellers vouch for authenticity.

Our unit had to move base some 100 miles, so enterprising individuals arranged for the use of some trucks. Problems arose when the owners of said trucks found out about their misappropriation (read stolen). Those ROK troops sure can't take a joke, absolutely no sense of humour.wonder if TB379 was a high backSerial SM410 was the first XVI to have the bubble canopy, but seems to be a trials aircraft. Listings don't identify low/high back.

[b1lanc]

Post elsewhere suggests metal in the oil from one of the Hurricanes but I guess that isn't confirmed.

Interesting - reading the progress report on NX611, the oil filters were removed in during winter to inspect for metal suggesting internal component fatigue or failure.

[treadigraph]

There is a comment elsewhere that cracks were found in the reduction gear on one of the Hurricanes.

[Fareastdriver]

cracks were found in the reduction gear on one of the Hurricanes.

Fix it with Araldite. There were strong rumours that a small Central American airline flew its aircraft for years with such a repair.

[treadigraph]

Far East wan't it? Air CamBodge...

[JonnyT1978]

On the subject of detail or minor differences between the RR Merlin 60 series and the Packard V-1650 series, I seem to remember reading an account by Raymond Baxter (of BBC fame) describing his experiences flying a Spitfire Mk.XVI on low-level ground-attack missions over Europe in the latter part of the war - I think it was in Spitfire: Portrait of a Legend by Leo McKinstry.

Anyway, Baxter recounted talking to Ronnie Harker after the war, who admitted that various refinements and detail changes were made to the RR Merlin which did not make it 'across the pond' to Packard. These changes were apparently to solve issues with the Merlin 'running rough' at certain power settings, a point Baxter had been keen to ask Harker about, as the power settings in question were those he and fellow Spitfire Mk.XVI pilots used for normal cruise power(!)

[megan]

if a Merlin Spit were re-engined as a Packard Spit, would a IX turn into a XVIYour question had me intrigued Danny, so did a little reading. The IX had the RR 66 as one option, and reference material hints that the Packard 266 is a RR 66 copy. Well, they are in terms of ratings, but the devil is in the detail, the British production Merlin 61, 63, 66, and 70 had a flat-topped intercooler and a separate, firewall-mounted header, whereas the 266 had the header tank integral with engine, which meant a different cowling with filler doors in another location. It is suggested that the location of this filler door is the only external means of identifying a IX from a XVI. See below for XVI installation.

http://www.spitfireperformance.com/packard266-intercooling-system.jpg

IX installation. #3 is the fill point. #2 would be about the location of the fill point on the 266 above.

http://spitfiresite.com/uploaded_images/hucknall-IX.jpg

[Wander00]

Anyone any idea when BBMF will be flying again? Guess they won't make Bournemouth

[jolihokistix]

Fingers crossed for an event at the beginning of September, weather permitting. Not looking hopeful though.

[Shaggy Sheep Driver]

Interesting, megan. Did big supercharged air cooled radials have liquid cooled intercoolers as well?

[megan]

SSD, can't think of any that used liquid cooling, all air.

[IcePack]

Hurricane (I think) at Clacton on Sea airshow today. Great display & sounded really smooth. Anyone know who's.

[DaveReidUK]

Hurricane (I think) at Clacton on Sea airshow today. Great display & sounded really smooth. Anyone know who's.

Hangar 11's example, according to the link in the Show programme.

Hawker Hurricane Mk IIB BE505 (http://www.hangar11.co.uk/hurricane.html)

[teeteringhead]

SSD, can't think of any that used liquid cooling, all air Apologies for threads drift, but was reminded of Herr Porsche's (alleged) remark when asked why his engines - VW and Porsche - were air-cooled....

"ALL engines are air-cooled ........... but some designers put liquid between the engine and the air!"

[treadigraph]

https://www.raf.mod.uk/bbmf/news/index.cfm?storyid=D278B6CC-A724-6BE8-7A12C1F5FFC2F90A

"Our investigation has confirmed an issue with a pinion gear in a Merlin engine. With the precise cause of the problem known, each pinion gear is now being inspected to confirm it meets our exacting standards, with the BBMF and industry putting all of our efforts into getting these beautiful aircraft safely back in the air as soon as possible."

[Thruster763]

I was at BBMF Conningsby today and word is they hope to have 2 Spitfires, 1 Hurricane and the Lancaster flying this weekend if all goes well. One Griffon engined Spit is already cleared. Yes the Griffons were checked as well as the Merlins.

[Blacksheep]

Why, of all the hundreds of parts in an aero engine, this one item should be singled out, is beyond me. Perhaps it was the easiest of all to take out and get lost.Regular spark plug changes as a set - along with the harness.

They had to be cleaned, gaps set and then individually tested for leakage and operation on a special test rig. The ignition system was critical in getting the required power output and smooth running. Did you ever notice piston engined aeroplanes turning into wind and running engines at full power before entering the runway? The pilot would set high power and then switch off each magneto in turn to see if there was an RPM drop ("Mag Drop"). If there was, the aircraft doesn't fly - it goes back to the flight line to have an ignition system change.

[Danny42C]

megan (#31),

Sorry for the delay in this reply - but thank you for your full explanation !

Danny.

[megan]

The pilot would set high power and then switch off each magneto in turn to see if there was an RPM drop ("Mag Drop"). If there was, the aircraft doesn't flyIf the aircraft doesn't have a mag drop it means something is wrong, equally if the drop is too large there is something wrong. The permissible drop is spelled out in the pilot notes. For the particular version of Merlin I checked, the drop is to be no more than 150RPM.

[treadigraph]

The Lancaster is airborne, presumably on an air test... :ok:

[DaveReidUK]

The Lancaster is airborne, presumably on an air test... :ok:

Scheduled to appear at the Scampton Air Show today, together with 4 Spitfires (the latter may be a tad optimistic).

[oxenos]

If the aircraft doesn't have a mag drop it means something is wrong,

Before the mag drop check at high power, a check would be made at low power, which involved switching both mags off together and straight back on again. The engine should cut out briefly, and pick up again. If it does not, you have a live mag. This was done both before and after a flight - if a mag was live, the engine could fire when the groundcrew were turning the engine over by hand, with nasty results. (the groundcrew on Shackleton Squadrons liked to line up the props- looked nicer.) Live mags were rare- only saw one in 2500 hours on Shacks.

[Lancman]

Long time ago but I seem to remember the the mag. check was carried out at zero boost, before the rpm were up in the propellor constant speed range. An rpm drop was essential but not to exceed 50. If there was no drop you knew that you had a live mag. and you knew which one. (Banter) see your 2500 hours on Shacks Oxenos and raise you 800 on Lancs as well!

[oxenos]

O.K. I Fold

[wowzz]

Saw the Lancaster flying today at Scampton.

[DaveReidUK]

Saw the Lancaster flying today at Scampton.

Accompanied by any Spitfires ?

[andytug]

Accompanied by any Spitfires ?
Hurricane and Griffon Spitfire apparently.