Ford aero V-12 of WW 2 attempt

[elephantshampoo]

1 piece Aluminum block

"Merlin was a single overhead cam engine with rocker followers, whereas the GAA is a true double OHC engine with the cam lobes directly acting on mechanical buckets. The Merlin's spark plugs were located on the exhaust side of the head just below the exhaust ports, whereas the GAA had its plugs centrally located in the combustion chamber, as per modern practice. The GAA featured a patented "power divider" gearbox which drove all the cams, pumps and distributors, where-as the Merlin used a more conventional setup. Finally, the GAA featured a one-piece block casting, but the Merlin featured a split block casting. The confusion between the GAA and the Merlin arose because they both featured the same bore and stroke (5.4" x 6.0"),"

[elephantshampoo]

Henry Ford vowed to build an engine of the exact same size, but which would be more technically advanced and with more power than the Rolls.






www.fordgaaengine.com/

Ford had pioneered the one-piece V-engine block with its early flathead V8s. Up to that time V-block engines were of a split-case design. The GAA engines continued this innovation. The block itself is of a contemporary short-skirt design, with a full length horizontal reinforcing rib. It is a side-oiler block, no doubt being an inspiration for later 427s, among others. The initial 12,070 engines also had 4-bolt mains with a double splay stud arrangement.



the army went to Ford and in effect said, "Look, we don't need another aircraft V12, but we do need a good tank V8." Ford then took the casting cores for the V12, chopped off the rear 4 cylinders, and the GAA V8 was born. To facilitate a quick production startup on the engine, it was decided to keep the existing design, which meant that the engine stayed as a 60-degree V-engine, and because all the design, engineering and coring was for alumunum, this feature was kept as well. Thus we have the Ford GAA, an "accidental" engine of the finest magnitude, likely the biggest light alloy, water cooled V8 engine ever built.


the V-8 version went into the Sherman.
www.fordfe.info/Sherman.html

[elephantshampoo]

For occasional sheer stupidity, the US Army really shines. The Pershing tank was not only delayed, but think for a moment if they had the wisdom to make this V-12? It could've gone not only into US fighters, but into the underpowered Pershing tank. 500 hp ain't much for a 40 plus ton tank.

Make that 450 hp. & 5 mph cross-country speed.

militaryhistory.about.com/od/vehiclesarmor/p/m26-pershing.htm

[errolmartyn]

I think you may have posted this on the wrong forum? We are about New Zealand aviation here.

Errol

[Dave Homewood]

This is in the Foreign Air Force Board Errol, but I do see what you're trying to say, there may not be a lot of interest as we mainly focus on kiwi topics.

[nuuumannn]

Undoubtedly interesting, but perhaps if it were put into a more relateable way for the audience here - we are no strangers to Merlins? Doesn't have to be directly related to New Zealand, but putting it into a more relateable context is probably what's required.

[suthg]

The book Allied Aircraft Piston Engines by Graham White, SAE Inc USA 1995 goes on to mention quite a few unknown and never completed to production large aero engines including the Wright R-2160 Tornado (42 cyl 35.4L), Lycoming's XR-7755 (36cyl 127L) and an earlier O-1230 doubled to make an H-2470 (24 cyl H style), then there was the Chrysler IV-2220 an inverted V16 at 36.7L They all failed to impress for one reason or another, but there was no mention of this Ford GAA V12 improved Merlin, although it does sound rather interesting to me as an engineer.

The Brits were not to be left without trying some options as well - Rolls Royce had their fair share of "duds" as well, take for instance the Vulture - a multiplied up Kestrel but with 90deg spacing to make an X shape with even firing for an X-24 (42.47L). They used the merlin crank spacing for bigger journal bearings and the possiblilty to oversize the bore later on. Unfortunately the use of a master rod and link rods for the other three cylinders in that circle did not work practically and was the downfall of the design.

Another engine they started much earlier experimenting with was the EXE - a new proposal using sleeve valve technology in 1934, a 90deg X-24 22L but aircooled.
After this was the water cooled Vulture mentioned above.
They also tried again with the Pennine - another X-24 of 45L size and 2750HP - the first oversquare higher revving engine they looked at.

Rolls Royce, after taking over Bristol and annexing Napier, liked the idea and concept of the Napier Sabre and set about making their own H-24 water cooled sleeve valve engine called the RR Eagle 22. This was larger in size than the eventually successful Napier Sabre, but included engineering improvements for ease of maintenance and assembly and larger at 46L cf 36.7L and likely much more HP, reportedly running at 3500HP at 3500rpm. It had its own teething problems as well, but the jet engine overtook all piston engine development and they were all stopped, as the jet age had arrived, with much higher HP and lighter, more compact engines, which still had their inherent issues for control and were slow to accelerate, and fuel consumption was an issue as well.

Oh I forgot another engine, the RR Crecy, the ultimate two stroke engine!! A 26L V12 with supercharger and an exhaust turbo-charger for 1800HP at 2500 rpm (long stroke engines) 1.128HP/cuin, (51.4kW/L) 0.95HP/lb, still not earth shattering results and then there was the fuel economy to worry about. (First run in 1941).

There are a lot of stories of engines that "nearly did" but got wiped off at the experimental stage. The Germans and Italians too had their large engines - X-24's V-24's and H-24's as trial experimental engines, some flew but never gained widespread acceptance.

[elephantshampoo]

Thanks for heads up Errol. I won't go into a sidevein/offshoot of this & talk about the wartcovered attempted progress of the M-26/M-46, 47, 48 series then. Or go into the "why V-14's aren't the hot set-up" topic either.

[nuuumannn]

Rolls Royce had their fair share of "duds" as well, take for instance the Vulture - a multiplied up Kestrel but with 90deg spacing to make an X shape with even firing for an X-24 (42.47L). They used the merlin crank spacing for bigger journal bearings and the possiblilty to oversize the bore later on. Unfortunately the use of a master rod and link rods for the other three cylinders in that circle did not work practically and was the downfall of the design.

Hi Suthg, good summarry, but RR managed to sort out the Vulture's issues before it was discontinued, in the Vulture V fitted to the Hawker Tornado. Hives felt that the Vulture had no future as the only aircraft powered with it at the time was the Manchester and Tornado, whereas the Merlin, which took precedent was powering almost everything else.

The primary issue was master rod bolt failures, which resulted in the crank case halves separating and enabled the whirling innards to flail themselves to bits. Two different bolt sizes were used and the shortest bolts were the ones failing. This was also the result of mating faces between the case halves being subject to enormous loads at take off power, which also contributed to bolt failure. The issue was sorted relatively quickly once a diagnosis was made, the cases were reworked and longer bolts fitted as well as mating faces between cases being strengthened and improved. Recommendations for lower rpm at take off power, but higher boost placed less strain on the bolts and mating faces.

[elephantshampoo]

Well, something came out of the thread. But I think I'll check out here, probably not gonna fit in too well. Happy Holiday gents.