The Reno Racing Engines (1 Viewer)

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"All the Reno engines are supercharged"

And how many of them were not supercharged in stock form?

And like I say very few modifications. So are modifications prevented by FAA?

The mention of drag racing stuf, is a good one. Some of those engines make what one or 2 runs for a whopping run time of
say 2 minutes (burn out, staging etc) or so, a full power blurp at 6 or so seconds. And get torn down for a refresh overhaul.
Well I could be wrong, looks like some overhaul after 1 run. After 8 passes 2 miles the crankshaft is junk.
Racing aircraft engines don't even come close. Top fuel drag racing they are attempting to get as much HP as possible from a very small package, sometimes they are lucky and sometimes not.
 
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Reno Gold Class unlimiteds are are highly modified. You ask if the FAA prevents engine mods? No.

A true racing Merlin today, such as is in Strega or Voodoo, is worth well over $500,000. The number of people who KNOW how to modify a Merlin without destroying it are very few. The trick is to make yours powerful and able to survivie a race intack. The mods are done to make things better ... not to go experimental a toast a half-million dollar engine. It is just a matter of economics.

The real merlin genius was Dwight Thorn, but he has passed away. So the merlin gurus are VERY few and far between tehse days, and they donlt guarantee anything.
 
The Rolls inlines as well as the Allison, are very lacking, I had a chance some years back twisting bolts on both makes. I'm very surprised they can stay together at the HP numbers some folks are extracting from them. I like them both. But
 
I wonder exactly what it is you think the Rolls and the Allison are lacking? The Allison is, by far, the stronger engine case and crankshaft, but the Merlins are no slouches if you use hot rod parts where needed for racing. They are definitely NOT lacking for stock power outputs, don't you think?

Maybe you could tell us what "very lacking" means, technically? Just curious since I am twisting wrenches on both makes.
 
Its not an internet subject to go into details.
Since you also have twisted some bolts on them, maybe you could share what kind of problems you have seen with ones that have had any form of failures or such types of problems.
 
Sure. Actually, the intenet is not a bad medium for talking about these things.

On Allisons, there is a mod that some people run that was started by John Sandberg. The Allison has an olil ring on the bottom half of the pistion, and three rings in the top of the piston. JRS (John Samdberg Racing) came up with a mod by which they cut the bottom of the topside rings wider and put the oil ring there, with two compression rings on top of it, and eliminated the bottom ring. When you do that, the piston slaps around a lot, particularly at around idle and just over idle and you typically must then overhaul the Allison at 250 - 350 hours when the slapping cracks a cylinder liner or trashes one or more pistons.

The solution is to run stock pistons instead of the JRS mod. The reason the owners liked the JRS piston mod is that they could change a cylinder bank on the aircraft, without removing the engine.

If you use stock pistons, you must remove the engine to change a cylinder bank becuase the ring compressors slide into the engine crankcase when you lower a cylinder bank on, and most aircraft mounts do not allow you to remove the oil pan when the engine is in the mount.

Also, if you run the Allison hot, you'll crack a cylinder liner and start venting coolant into the cylinder and out the exhaust. If you continue to fly it, it will fail eventually. Mostly, if properly built and run, the Allison is pretty bulletproof.

The failures I have seen are mostly in tractor and boat engines that are run well past aircraft rpm levels (3,000 rpm). The main indicator is shrapnel. When a tractor guy blows an Allison at 4,200 rpm, pieces fly. In aircraft, I have seen coolant issues due to water pump cavitation (caused by owner mods to the system), one failed distributor (landed OK on one cylinder bank), and cracked cylinder liners due to overheating by the pilot. Otherwise, mostly the odd failed part that was discovered on the ground before flight. Magnetos, improper routing of electrical or oil / coolant, and fouled plugs that the owner is just too cheap to replace!

As for Merlins, while they aren't nearly as strong as Allisons, if you run them in stiock form, they are just fine with stock power output. The center crank bearing retainer is scarce and sometimes gets broken, meaning you sometimes need to find one or make one, but most often not. The biggest issue with Merlins is the about 40 years ago, they used to throw away engine parts when they started wearing out and put new parts in. That was VERY shrt sighted and today they are flying parts they would have thrown away 40 years ago. The bottom line is Merlin spares are drying up and that is a big disadvantage to owning and flying a Merlin. I don't think anyone has done a JRS piston mod on the Merlin (but am not altogether sure), and that is good becasue it would also not be very long-lived.

When they actually break, say in racing or in service when a failure is experienced, I have seen rods and piston go, holes in cases and, in one case, the engine stopped because the camshaft drive failed and the distributor simply stopped. To be fair, I heard that happened once in an Allison in the last 10 years, too, so its not a unique weakness to the Merlin.

One weakness common to both Allisons and Merlins is the radiator. Good radiators are hard to find and are expensive!

Generally, both of these engines are very reliable in operation and last well past typical wartime TBO if built and operated correctly. Neither one is especially suited to 3,000 HP but, of the two, the Allison is better suirted to handle 2,500+ HP than the Merlin die to the strength of the cases, the case studs, and the rods and cranks. Most "
failures" I have seen are from racning, not from typical warbird operations. In warbird operations, the typical issue is overhaul when it is indicated, not engine failures.

The rub is that the people who know how to properly build an Allison or a Merlin correctly are getting fewer. The people qualified to modify one for racing are even fewer yet, and getting less as they get older and retire or worse. The supply of propellers for North American P-51 Mustangs is depleted and they are searching for new blades they can adapt to the existing P-51 prop hubs.

The R-3350 engines are, by far, the worst off, They are simply out of main crankshaft bearings. When the current crop of mains is used up, they will become museum pieces unless someone starts producing new main bearings for a very small market. Fortunately, there is still s pretty good supply of R-2800 mains avaiable, so the R-2800 crowd is doiong the best of any of the bif radials in that regard.

Tell me, what failures have YOU seen while turning wrenches on Merlins and Allisons? Donlt tell me it is too technical and reply with a 2-line post, give us a summary of failure types you have seen and the reasons you uncovered like I posted. C'mon, it ain't that hard to write a paragraph.

Something in there makes you feel the V-12's are lacking something and I have been impressed the other way, with the reliabiolity of these engines. At the Planes of Fame last year, we flew 31 warbirds for two days, anywhere from 2 to 5 flights per day each ... and we experienced zero mechanical failures and not one single down aircraft due to engine or any other system. For what is generally a 60+ year old bunch of aircraft, that's not bad!
 
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Using Merlins in the racing venu, the center main getting hammered. Super charger stock quill shafts breaking, and of course the cam and followers wearing out. As well as things you have mentioned. Both Allisons and RR are nice looking engines, but looks only goes so far. You have pointed out alot of the issues that I've seen and heard of. They are like you mentioned a very old design, and were a good design back in the 40's for what they were meant to do. It would be nice to have the funding to improve one or the other, and it would be a complete face lift, it may look similar, but nothing would be the same.
 
Good points engguy. I have long wished for a new design of about 1700 - 2000 cubic inches, that can run upright or inverted, with fuel injection and electronic ignition, that produces about 1,600 to 1,800 HP and can fit wherever an Allison, Merlin, or Daimler Benz 603 / 605 could fit. Also, they could make two front gearcases that could be symmetrically reversible to allow mounting the prop in the center (one case) , high or low (a second gearcase) as required by the WWII fighter design. The engine shoudl be designed so it could be configured to turn the prop in either direction.

That way, the Hispano Ha.1112 aircaft could be returned to Me 109 profiles, and Italian fighter replicas could be made and practical. Maybe even a Finnish VL Pyorremyrsky could be built and flown. As of the present, these types of aircraft are not viable due to lack of DB engines and props. of course, you;d need the aviation authorities in the various countries to allow replicas without original data plates since so few rare data plates are in exitence.

These things are possible, but the funding would have to be substantial and the market is small. Certifiction is out of the question due to cost, but it might earn experimental status for substitution in warbirds. If we get this new "warbird" engine, we'd need left and right-hand props to go with them.

Since you are an engine guy, maybe that gives you some ideas ... and maybe you already HAD those ideas. if I were 25 years old, I'd join in and help out. But I'm not and don;t have any funding to help out. I hope the warbirds keep flying. I love 'em and many outhers in here do, too. We may fight over Lancasters versus B-24's, but we'd ALL love to see either one fly by ... or get a ride in one, wouldn't we? :)
 
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25 YO! Its only gona be us old guys that would do it. The kinda difficult thing is to attempt to give it the same outward appearance of what it would replace.
Or is that important? If you want it to look good put an old RR or Allison in it for looks. If you want to fly or race use the new one. ??? Oh in the above forgot the most important the con rods. I agree with keeping the old stuff flying and racing. But as with the engine, I would really like to see someone build some new airframes too. In some of the restorations I think that pretty much happens. Like with Glacier Girl.
 
The engine I was speaking of is a V-12 specifically tailored for stock warbird flying. It could be made so the stock cowling could be used and suitable exhaust stacks could be made. That's why I wanted tio to be able to run upright or inverted ... not for aerobatcis specifically, but so it could be used in lieu of either a DB or a Merlin / Allison / Mikulin / Hispano.

I had not considered a Reno racing engine from this powerplant due to the limited market compared with stock warbirds.

I am with you in that I want to see new airframes raced. The Pond Racer was a good start that was always plagued by the engines. I truly believe the real issue was the intake tracks, which were made of rubber. I believe they collapsed under high manifold pressure, causing the engiens to go suddenly lean and fail. If they would have made rigid intakes, I think they might have been succesful.

The other original airframe was Tsunami, and it was a very good one that experience a simple flap system failure which ended its career way too soon. I have spoken at length about Tsunami with Pete Law, who is a frequent visitor to the Planes of Fame. He and Bruce Boland werre the Tsumani design team.

Pete still maintains it s possible to get better than Tsunami, but acknowledges that the good Merlin engines may be gone before anyone builds a better arrframe.

So we come around to a new Reno engine. It is possile, given funding, but the market is not only small, but also may disappear altogether in light of the Reno crash this past month. I certainly HOPE not, but there are always bleeding hearts who want everything stopped when someone gets killed who is not a participant in the race ... even if everyone there DID accept a waiver of damage /injury and the right t sue when they came in the gate and put on the wrist band. We'll see, won't we?
 
Pete is a very cool guy.
I am with you about the racing. It would be a real shame to not have them anymore. Oh well I guess they never had any races of anysort in USSR either.
Yes what is needed is some new and improved war bird airframes, that look like the originals but improved so problems like GG don't happen again. But this needs to stay on topic, Engines.
 
I believe the engine is what I was talking about and so were you, and your comments about new airframes are spot on.

So, we need engines, props, and airframe ... not to mention tires and brakes.

Let's get to it!

I want to see 550 mph around Reno ... assuming Reno still exists ...
 
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There was some racing in the USSR, icespeedway, some 175, 250, 350 500cc road/track and on off trials, endurance motorbike racing.
Even once an idea (or rumour...) of a possible Soviet Bloc F1/Indycart with 1000c 2S/2C V engines in 80's/90's afaiu; I forget if they were going to be 2 Stroke V6's, V8's or V10's.
 
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The racing in ussr was a pun on whats going down in this country.
550 at reno yes and why not 700?
 
700 at Reno would be tough or impossible. They bought up all the property they needed around Reno (and sold off some of the buffer zone!), and it already takes about 3.5 - 4.0 g around most of the course at 500 mph. At 700 mph, I doubt the g-forces required would allow that sustained speed or be safe enough for racing. Nobody wants to race at 5 - 6 g's almost all the way around the course, not even Navy Top Guns. And it would not necessarily be safe for anyone around the course permieter.

If the course were circular (and it is not), the and 500 mph, with a radius of 4300 meters, they would be pulling 1.2 g's in a circle. Since it is not a circle, they actually pull about 4.0 g's ariound the ends of the course. I calculate that at 700 mph they would be pulling about 7.8 g's around the same course.

Now if they moved the race out in the desert, away from a city, perhaps. I'd want to see a course that would allow 3.5 - 4.0 g for a 700 mph class beefore wanting to try it for real, and the FAA would have to agreee it is safe.

I could be wrong ...
 
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I crewed a Jet at Reno - the Viper powered L29s were getting close to 550 (543 mph is the current course record held by Curt Brown) and on a cool morning can get buffet depending where the C/G - MAC is. I actually had to move the CG forward on my jet as my pilot felt the aircraft was getting a bit unstable. Personally I doubt you're going to see any prop driven aircraft going more than 550.
 
I KNOW Strega will make 540 mph in a straight line. Around Reno, it will probably get to 520 mph if pushed all the way arournd at max power. To go 30 mph faster would probably take a new airframe.
 
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If a Jet plane can go what ever speed, theres no reason the other powered one can't. Its all in the proper airframe design. And power delivery.
 
If a Jet plane can go what ever speed, theres no reason the other powered one can't. Its all in the proper airframe design. And power delivery.
Not true - you are limited by propeller blade speed especially around the tips that will see supersonic speeds. As propeller speeds approach the speed of sound not only will you have adverse stresses placed on the propeller, the blades themselves will become very inefficient. This plagued prop/ jet experimental aircraft from the 1950s.
 

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