Warbird Information Exchange

Right on BDK. The procedure is sort of an aviation version of blood doping as done in endurance sports. You take the Allison rods, run them in a race Merlin at Reno for a few practice laps. Then when you put them back in the Allison you have a little more power. I think Dwight Thorne developed this.

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Bill Greenwood
Spitfire N308WK

Bill,

“….You may more time working on these engines, than I have flying them”.

That’s my point behind the comment that there are better mouse traps out there. Others are less complex and more simply engineered, break down less frequently and require less maintenance to maintain peak performance. The Merlin does not fall into any of the categories listed above. On the flip side, it is sexy and elegant which is very typical of British engineering, it sounds great and looks like a million bucks. It most closely resembles a high maintenance show girl. Fun for a day but who wants to be married to that? You guys (pilots) get her when she’s already for the show and us maintenance guys get her when she steps off the stage all hot, sweaty and ready for the shower. YIKES! Get the make-up off of her and she loses her shine real fast! With all due respect, the British engineers (At least of that era) could engineer the simplicity out of anything….that simple statement could be the reason behind why the Brits drank warm beer! All of that aside, I do like the Merlin but it can test your patience on many levels! Before our UK contingent becomes unhinged at those statements, I’m just picking at you all in good fun!

“…what I meant about nationalism is that America and Lockheed may have wanted to use US engines if possible”.

I see. In the case of the P-38, as I recall reading Lockheed actually wanted to switch to the Merlin and fought to get their request approved but in the end it was denied because of the concerns noted earlier in this thread. It’s a prime example of the give and take required maintain the war effort at the time. I think there were a lot of other aircraft at the time that could have been much better performers if they were powered with the engines the engineers really wanted in them. The R-2800 in the B-25 is another example. It still blows me away how many engines P&W built during the war years! Even with that staggering number some otherwise stellar airplanes became “Thursdays Children” and were relegated to capable rather than superstar status.

“…would not be surprised if Rolls was reluctant to share their hard earned technology with the colonies. They were a private for- profit company after all…”

All of the US and British companies who built aircraft for the war effort in were private for–profit entities. We were fortunate enough not to have to share our engineering with others…only because we were not in the war zone and had the resources to produce what we needed largely by ourselves.

“…There is an interesting book "Not Much Of An Engineer" by Stanley Hooker who was hired as a bofffin (theorist) knowing little about engines and became Sir Stanley by improving the Merlin supercharger. The 1st part is great about Rolls and the Merlin, and the last part about the jet engine development. Also a more technical, less entertaining one "Merlin In Perspective".

Thanks for the tips on the books (Erik H. you too!). I’m always interested in the histories of, and learning more about these aircraft and engines.

“Yea, I've got a warm spot for the Merlin, as do thousands of Spit, Hurri, Lanc, Mossi, Mustang etc. combat pilots from Bader to Yeager.”

As do I! As do I! I too think it is a good engine. Without it we most certainly would be speaking German right now.

“I've got to doubt your sanity a little bit; anyone that willingly spends the winter in Minn!”

My “Will” to live here is fading with each subsequent snowless winter…the -15 F reading on my digital thermometer this morning didn’t do anything to fortify my reasoning for staying either! I hate the bitter cold but like the snow. Look in the mirror Bill…the last I heard Aspen is not a lot warmer! Have me out sometime and prove me wrong!

John

Yes, all of the "mouse" merlins that are running in the top inline unlimiteds such as Strega and Dago Red use the Allison rods. At least they did when Dwight was building them. I assume Sparrow still does as well, but not sure. Maybe he will see this and chime in. As for the race Merlin vs race Allison debate, I think it is a matter of years of development. The Merlin builders have years, and years of learing how to push them well beyond 100" at race power. The Allisons might be able to do it as well, and be as fast or faster, but who wants to spend the $$$$$$$$ and parts to figure it out?

All the serious inline racers recently have been Merlin powered Mustangs. There has not been a reasonably serious Allison powered contender since John Sandburg raced his P-63, although earlier "Mr. Mennen," a P-39 flown by Mira Slovak and I suppose maybe Larry Havens' P-63 also but it never made it to Reno.

Seems like there were a lot of Allisons in the races right after the war though. Didn't some P-39s do quite well- Cobra I and Cobra II?



I can't imagine a P-39 capturing the piston engined speed record, but they must have known something!

P.S. Was Woolams' P-39 ever recovered from Lake Ontario?

Oh Bill, Bill, Bill...

Have you seen this video yet of Dave Morss flying the Allison-engined Polar Bear in last year's Bronze final? Every now and then you can catch a glimpse of the P-51D that Mr. Morss finally smoked for the trophy.

Enjoy!

http://www.youtube.com/watch?v=umU6-yY_P2c

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It was a good idea, it just didn't work.

There are good and bad points to both engines. First off, Ford Motor was originally offered the contract to built Merlins, but after Henry Ford spent quite some time and a sizeable amount of money trying to re-engineer it, Rolls took it away and gave the contract to Packard, who of cousre followed it through. Packard made a lot of imporvements to the engine's but mostly made them able to be built "production line" style. Rolls didn't do this, all the of engine's were built and finished by "hand fitters" on the floor of the plant.

In regard to "Transport" Merlins, 600 through 724-1C series of engine's used most familiarly on the DC-4M "Northstar." Initially they had alot of problems with these engine's putting them into use for a commercial application with the build of a "new" style (transport) of engine. Rolls, to their credit, and great expence, stepped up to the plate and worked with the airline companies to cure the problems and make the engine's work. They had engine's that they ran 1000 hrs, did a top overhaul and ran another 1000 to TBO. Much the same as the radials TBO. On the DC-4's, Merlin's replaced the PW R2000, which from most of what I have been told by people that operated and maintained them, were a turd of an engine plagueg by problems. The R2000 after all was an 1830 cobb with bigger cylinders. Just increased the stress loads throughout the engine by doing that.

To the fellow that asked about Allison pistons, they are symetrical. Allison has a 5.500 bore versus Merlin 5.400 bore, 6 inch throw in both. Once again, to change the rotation in an Allison, first step is to turn the "crankshaft" end for and set the accesory case of the engine up for desired direction of rotation. The fellow that quoted fuel flow figures, those figures are high for a Merlin, I of course don't know the power setting used. Dan Whitney is a friend of mine, I could ask him about that. Todays Merlin's, at least mine, I have the carb flowed to the rich end of the stock flow chart. At a setting of 23/36 the fuel flow should be 67/68 gals per hour in AL. The value in AR would probably be 76 +/- gals per hr.

Well, British engineering eh John??? Like Hives said about Sir Frank Whittle's jet engine-- "We can engineer the simplicity right out of it!" A Merlin engine, compared to an Allison--- there is NO comparison, other than the fact they are both V-12's. An Allison is a very practicle, well thought out, nice simple engine. (No dis-respect, just simple fact) Merlin's are an absolutely georgeous piece of work. Yes, they do test your patience. Merlin's are like P-51's, they require you to provide them with the amount of time THEY feel is required, if you draw up short--- the damned thing will screw with you until IT is happy!!! So, in that regard they can most certainly be a pain in the ass!

As far as Allison rodded race engine's, yep--that's me. Use the best parts from Rolls, Packard & Allison. When everything play's nice and works like it's supposed to, they are an incredibly potent & powerful engine. Dwight really created quite a machine and I was fortunate enough to have worked with him for many years and had the oportunity to learn.

That's more than I have typed on one of these thing's for a long, long time. Maybe I answered some questions.

Sparrow

Sparrow obviously knows far more about these engines than I do but I've a couple of points here.

Henry Ford refused to build Merlins in the US. It was when he was still being isolationist and didn't want anything to do with them.

Ford in the UK re-drew the Merlin to automotive standards. I think Hooker said it took a year but was very successful. Packard I believe did the same.

Rolls engines from Derby and Crewe were certainly hand-finished, if not quite hand-built. However the Glasgow factory used a lot less skilled labour and I wonder if they used different drawings. From what I've read, I wouldn't have thought they had enough skilled labour for the same extent of hand-finishing.

In one of the RRHT (Rolls Royce Heritage Trust) books, there are several chapters pertaining to Henry Ford and the Merlin engine. He spent quite a period of time and a lot of the companies money trying to re-design the Merlin, for among other things, the use of automotive style side by side connecting rods rather than the fork & blade configuration. The book indicates that when Rolls got wind of the fact Ford was trying to "pirate" their design so to speak they pulled the offer of the contract away from him and offered it to Packard. It is also my understanding that due to the fact the Merlins were being built by Packard that they were indeed the ones to create all the required drafting and incorporated changes to build the engine's using an automotive style production line system. For what it's worth, to this day, Rolls still considers most all of the infomation regarding Merlin engine's proprietary and won't divulge design/construction info.

Regards, Sparrow

I just realized I think I have only been in one Allison engine plane, got a good ride in Tiger's P-40 once. Neat airplane, good pilot! Does anybody know much about the Merlin in the P-40?

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Bill Greenwood
Spitfire N308WK

The Merlin in the P-40F and P-40L was a the V-1650-1. The F model being an E model with a Merlin and the L model being a long tail K model with a Merlin. Of course the V-1650-1 used in the P-40 only having the single stage and no after cooling was of the same power as the Allison models. They also had problems with engines eating sand because of the updraft carburation and the inablity to have an airfliter system with arrangement of the coolers and cowling. Which of course became a large problem do to the fact that most Merlin powered P-40's were operated in the Med. and Africa. Dan Whitney states in his book that the original program provided for 12 percent spares and the actual usage was about 35-50 percent! The end result was to remove the Merlin and re-install the Allison and this was the P-40R. They also had troubles with coolant temp control. The early models had an automatic system which they removed later by service bulletin and installed a manual "parking brake" style handle for simplicity ( like the Allison P-40's). The Merlin install ended up weighing more, which meant they had to add another 30 lbs to the rudder counterbalance to maintain the same weight and balance. Anyways, again in the words of Bob Diemert "It was a good idea it just didn't work"
To bad Diemert didn't put four seats in the Merlin powered P-40 he "built". Now that would've been an airplane!