RR Merlin- what are 'transport heads/banks' ?

[Flat 12x2]

I have seen in many P-51 Ads. ....Engine...Merlin with 'Transport' heads or heads & banks.
What is the difference to what must be 'standard' heads & banks to Transport ?
You can be as technical as you like as I build Hi-Po V8 car engines for another 'hobby'

thanks

Martin

[Dan K]

Hi Martin,

Here's a layman's definition (swiped from the Courtesy site):

There are a number of variables regarding engines. The basic engine is the Packard built V-1650-7. The V-1650-9 was also used and is interchangeable. This V-12 engine is designed with 2 removable Cylinder bank assemblies of 6 cylinders each. These are referred to as head and banks. There are a number of engines that have been fitted with the" Transport Heads." "Transport Heads" refer to British built assemblies that were used on a commercial aircraft engine and were designed for long life .

The basic V-1650-7 engine lower end will have a TBO in civil use of about 600 hours. The V-1650-7 heads and banks will probably require some rework at about 300 hours. The transport heads will normally last to TBO and beyond.

[Michel Lemieux]

Canadair built at one point a version of the C54 ? which had Merlin engines.

North Star Mk 1

I think we have an expert here on the board



These birds had uprated specs for the engines and the heads where a lot more sturdy for airliner use.

http://www.aviation.technomuses.ca/collections/artifacts/aircraft/CanadairNorthStar1ST.shtml

[airnutz]

Wasn't there another criteria for the Transport Heads concerning exhaust
plumbing placement? If I remember correctly, the exhausts were routed
outboard of the respective engines so the passengers in the airliners
wouldn't be alarmed at the sight of the long trails of flame streaming
behind the engines?

[mrhenniger]

I think we have an expert here on the board

If you are talking about me, and I am flattered if you are, then I must say I am not enough of an expert to provide details about the engines, although they did use the transport heads of course.

I am trying to get permission to post some pictures of the North Star, and one specifically which is a close-up of a crew working on a Merlin on a North Star during the Korean airlift.

Mike

[airnutz]

Hmmmnnn, I guess not ..going by the posted photo!

[Swiss Mustangs]

Maybe you guys remember that Mr. Lindsay of Trans Florida Aviation ( later Cavalier Inc.) modified the V-1650-7's of his Cavalier F-51 conversions with components from commercial Merlin 620's - he had acquired a number of retired North Stars and used those engines.

Martin

[mrhenniger]

Wasn't there another criteria for the Transport Heads concerning exhaust plumbing placement? If I remember correctly, the exhausts were routed outboard of the respective engines so the passengers in the airliners wouldn't be alarmed at the sight of the long trails of flame streaming behind the engines?

I have heard, via my occasional contacts with the work and research teams of Project North Star, that the Air Canada operated North Stars had some kind of snuffer exhaust, while the Air Force North Stars didn't.

Please someone let me know what the correct term is. I doubt "snuffer" is correct.

I heard an interesting story about how the Air Force was to transport the Prime Minister across country using a North Star, and that that the "snuffer" exhausts were be be installed for the trip. The Air Force bought a set from the airline in Montreal and brought them back to Uplands (Ottawa) to be installed. It turns out that something about the mount points or the cowl of the two North Star types (commerial and military) were not the same, and quite simply the commerial snuffers did not fit the miltary engines. An officer told the crews, in no uncertain terms, to make them fit. So the crews apparently bashed them into place. The flight left with the Prime Minister on board. When they landed after the first leg of the trip there were no snuffers to be found as they had all fallen off in flight! Yikes! Apparently the crew quitely inspected the plane for damaged and found none. After refueling the trip was resumed, unmuffled.

Mike

[Swiss Mustangs]

how about "flame dampeners" ?

Martin

[Flat 12x2]

Thanks to all, that all makes sense

Mike
A Northstar engine radiator intake cowling turned up on uk ebay last year, apparently it had come from the ex. Hawker/BAe Dunsfold airfield, strange part to come from there !

Martin

[mrhenniger]

A Northstar engine radiator intake cowling turned up on uk ebay last year, apparently it had come from the ex. Hawker/BAe Dunsfold airfield, strange part to come from there!

Maybe not as strange as you may think. BOAC operated the North Star as the Argonaut.

Mike

[Randy Haskin]

Maybe you guys remember that Mr. Lindsay of Trans Florida Aviation ( later Cavalier Inc.) modified the V-1650-7's of his Cavalier F-51 conversions with components from commercial Merlin 620's - he had acquired a number of retired North Stars and used those engines.

He and some other investors bought six Northstars and a number of Merlin 620/622 engine spares.

The engines that TFA built up for Mustangs which used the transport parts were called the Merlin V-1650-724A.

[airnutz]

It has been several years since I read "The Canadair North Star", by Larry
Milberry, 1982....and of course I remembered a detail wrong. The exhaust
mod I referred to earlier was actually developed to reduce the noise
levels within the cabin of the North Star created by the hammering effects
of 4 sets of exhaust stacks aimed at the occupants.

A Trans-Canada Airlines technical innovator, Merlin "Mac" MacLeod (No
Sh*t, Merlin was his real name) developed and designed an "exhaust gas
crossover manifold", which ducted the inboard-facing stacks over the
Merlin...using a large single collecter tube...which joined to 3 outboard fish
stacks resulting in projecting some of the noise away from the cabin.
A benefit of this design, was the flames of the exhaust were no
longer in view of the passengers at night. On the TCA North Star this
"crossover manifold" was built somewhat over the original cowling and
a fairing was designed which "dirties-up" the original smooth lines.

And as Mike said, BOAC operated the same aircraft christening it
Argonaut. BOAC came up with their own "crossover manifold" which used
3 smaller tubes running along side each other over the engine and joined
into a outboard "ejector" manifold which also doubles as the outboard
exhaust bank exiting 3 round exhaust stubs angled aft. Abenefit of BOAC's
3-tube design, was the profile of the cowling remained clean and sleak,as
the manifold assembly was within the confines of the cowl framework.

As for your "snuffers" Mike, Milberry doesn't seem to mention them. But
who knows what will turn up.

Another thing that is mentioned, is that TCA and others I suppose were
able to get the Transport Merlin TBO's up to about 1250hrs. Some of them
went quite a bit better than that. Early problems were encountered with
the engines because they wre cruising them at 1100 bhp...when they
reduced that back to 950, reliability was improved significantly. Although
that is a bit simplistic of a statement on my part because Rolls Royce
became aggressive about improving the reliability of the Merlin through
an agreement with Trans-Canada...the "Won't Be Sorry" agreement in
which Lord Hives of Rolls Royce,to a degree warranteed the Transport
Merlins. Effectively, as I read it ....having Rolls assume responsiblility for
developing a former military engine with a potentially short life in the
world of combat, into a reliable engine for airline use.

A particularly telling statement in the book, is this quote...
'As Lord Hives, the then head of Rolls-Royce was later to say: "Having
built thousands of themduring the war, we never learned anything about
the Merlin until you airlines started to fly them."

This is really a very good "read" of a book about the North Star! Not too
technical..plenty of pilot stories..crew stories ...Canada history. 251 pages
with a few foldout profiles.
edited 3rd paragraph

[agent86]

Me believes that them transportation type heads be more tolerant to abuse and maybe modifications or whatever and therefor the heads of choice over original fighter type heads.Makes perfect sense to me.

[Cvairwerks]

The transport versions of the Merlin were designed to operate at much higher continous power levels than the military versions. I don't remember the exact numbers but I think they were operated at 3000 rpm/ 60"MAP for cruise power with the military engines being 3200 rpm/65"MAP for takeoff power.