3.8 liter vs 38 liter

[turbofabricator]

Here's a picture of a Rolls Royce Griffon piston and fork rod assembly, from an Unlimited Hydroplane, next to a stock buick turbo piston and rod assembly. I use to build these monsters about 20 years ago. The engine is 2,240 cid, overhead cam, 4 valves per cylinder, two stage supercharged (two 14 inch impellers that spin at 24,000 rpm) and pressure carbed (kinda like Rochester fuel injection 'cept WAY more complicated) and nitrous injected. Designed and built in the early 1940's. And it took ALL that power just to turn a 15.5" propeller at 12,000 rpm. But if you want to go 200+mph on water, you better bring some poop with you. We were making about 5,000 hp on gasoline. We would go through 60 gallons of 115/145 av gas (with an additive in it) 25 gallons of 50/50 water/methanol, and 3-5 gallons of 70wt oil in about 6 minutes. God I miss the sound of those engines! :biggrin:
Ken B.

 

[Pablo]

thats pretty neat

what did it have ignition wise? A magneto? It would seem like that thing needed a hell of a spark or dual plugs to ignite all of that space. What rpm did the engine itself turn?

 

[Quiky One]

Wow sounds like quite the boat. Did you ever go 200?

Jason

 

[Nashty]

I see that rod has the rare right angle bolt pattern in the first picture. Very rare indeed.

What was that motor originally installed in? Is it a tank engine or something like that?

How big is the bore, stroke?

 

[turbofabricator]

It's a Rolls-Royce Griffon. The Big block to the Rolls Merlin. It has a dual magneto, dual plug ignition system. It has a 6" bore and a 6.5" stroke and is a twelve (12) cylinder aircraft engine. The single stage supercharged engines were installed in Shackelton Bombers and the two stage SC engines were installed in Ferry Firefly's and MK VIII Spitfires of WWII. It was a huge engine that was developed later during war effort (relatively speaking).
No, I personally did not drive the thing, nor would I if given the chance back then. We had just built the first enclosed cockpit and it hadn't been crash tested yet. :wink: Since we built the enclosed cockpit, under HUGE protest by other teams, there hasn't been a fatality on unlimited racing in 21 years! Prior to that the average was, I think, was 1 a year! The enclosed cockpit concept has been credited to Ron Jones, but that's REALLY not true. Jeff Neff was the real proponent of enclosed cockpits, and the Budweiser crew in 1985 modified the new carbon fiber Ron Jones hull into an enclosed cockpit, and had it approved by the URC. That was a HUGE engineering feat! How do you supply air to the driver, keep him cool, allow access when upsidedown-under water, facilitate roll cage safety, ect.

 

[turbofabricator]

The factory war time power settings were: 2,750 RPM 70 in. Hg. (approx 35 psi) manifold pressure. We turned the engines to 4,200 Rpm (equal to a small block chevy turning 11,000rpm as far as piston speed at mid stroke) and at 130 in.Hg. (approx. 60-65 psi depending on atmospheric conditions) The carburetor we used was a PR100 off a R4360 "corn cobb" radial engine. (4,360 cid radial airplane engine-28 cylinders) It alone wieghed about 35-40 lbs.!
We would also use 150 lbs. of N2O per heat race, if needed (Man, I hated filling (5) 30lb. bottles)

 

[Pablo]

Man that is awesome information, I am kind of a WWII aviation buff and this is neat.

Are any of those engines still around?

Also, were those originally set up for N20 or methanol/water injection? Most of the later european theatre acft had some "help" like that especially later in the war

 

[turbofabricator]

Yes Pablo, they are still being flown today. The Brits flew them maritime patrol untill the mid 80's I think (Shackelton) The Unlimited air race guys install them in the racers to this day. Do a search for "Rolls-Royce Griffon" and you can get a ton of info. Here's a picture of the boat I crewed on and a picture of the VERY same engine now in aircraft configuration (contra-rotating propeller shafts) I found this picture on the web last night and couldn't believe that they even left some of the brackets from the Hydroplane on the engine :tongue: The engine stand is the very ones we used in 1985. The stand is gold cad plated. Our policy was "If you cant polish it, chrome it, if you can't chrome it, plate it, if you can't plate it, paint it, if you can't paint it, you can't see it, so quit worrying about it!" The engines were painted with Imron. It was a piece of artwork in my opinion. The Brits sure now how to engineer engines. The piston alloy in the Rolls' is still the best to this day, and the crank and rods were 4340 forged. This engine was designed in 1939.

Ken B.