PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Does anyone have any inside scoop on these?
The Reno Racing Engines
- Thread starter PWR4360-59B
- Start date
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robwkamm
Airman 1st Class
take your yearly income multiply it by 3 and hope its enough. seriously i have no idea. but love the races and engines. hope somebody in the know tell us more.
Messy1
Master Sergeant
I am guessing at least a few hundred thousand on a cheaper engine. Imagine cost of Rare Bears rare R3350 to modify and rebuild. Anyone have any ideas cost of that?
FLYBOYJ
"THE GREAT GAZOO"
The plane I will be working on this week belches out a 10 foot flame when it starts!
vikingBerserker
Lieutenant General
Get pictures!
robwkamm
Airman 1st Class
ill bring the hotdogs.
FLYBOYJ
"THE GREAT GAZOO"
Got in yesterday. Started doing tech inspections on the jets. As far as the recip warbirds, the usual crowd, with the excpetion of "White 12" FW 190. Will try to get pictures today. I'm down on the west end so it takes me time to get over to the warbird side. After tomorrow my time should free up a little.
- Thread starter
- #8
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
I kinda hung around a Reno race plane at one time. There were pretty much zero engine modifications done except for maybe the cooling spray bars etc. I would like to get to help modify one for racing, I have never seen one yet with the ideas I have. It would be fun. I need the right connections!!!
- Thread starter
- #9
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
So how many engines blew up this year??? Some one that comes here must have gone to reno this year.
FLYBOYJ
"THE GREAT GAZOO"
I did - you'll see my post on another thread
Colin1
Senior Master Sergeant
I'm willing to bet
that there's none of your ideas that haven't been tried, in one form or another. Only my opinion, but I don't think there's much, if anything, left to squeeze out of even a late- or post-war recip.
You're right though, be fun trying
- Thread starter
- #12
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Never ever seen it done. Like I said, especially with the radial engines, there is pretty much zero modifications done.
Matter of fact last year 2009 race, rare bear was using one of the engines meant for FiFi the B29 of the CAF. Pretty much stock except for the parts swapped from other dash numbers. Like -26WD power section,blower section, and accessory section, cause it fit the engine mount. And -95W rotating assemblies and nose case. But this is just a parts swap deal not a performance modification deal.
Matter of fact last year 2009 race, rare bear was using one of the engines meant for FiFi the B29 of the CAF. Pretty much stock except for the parts swapped from other dash numbers. Like -26WD power section,blower section, and accessory section, cause it fit the engine mount. And -95W rotating assemblies and nose case. But this is just a parts swap deal not a performance modification deal.
FLYBOYJ
"THE GREAT GAZOO"
The only reason why Rare Bear ran a basically stock engine last year was because of $. I don't know what they did this year but I do know they their team worked late hours as we did in the jet class.
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- Thread starter
- #14
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
If there is any modifications they make they are small, nothing major.
FLYBOYJ
"THE GREAT GAZOO"
At the present time yes, the older engines were modified and had a NOX sys as far as I know. I do know they are run "over red line" and the engine - prop combination has a lot to do with its performance.
Vintageaeroengines
Airman
- 39
- Oct 20, 2010
Racing merlins at reno this year. some of the changes to #7, packard -21 supercharger and accessory case, Rolls -720 crankcase reduction gears and cylinder blocks, allison g series rods, custom bearings pistons and rings, custom cams, rocker arms with carbide inserts, modified mags and carb, custom ignition harness, internal and external bracing, modified oil system and classified timing and other settings. The speeds speak for themselves. The cost of the changes runs over $200k. The prize money pays for 1/2 of the engine.
- Thread starter
- #17
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Rocker arms with carbide inserts? Does the insert contact the cam? Are the cams DLC ed? Mag mods? Increase voltage?? For folks with bucks $200 K is like a $5.00 is to us normal folks. Guessing all the special parts are Roush?
Vintageaeroengines
Airman
- 39
- Oct 20, 2010
most of Roush parts are for stock engines. the carbide runs on the cam lobe. these have been around for over 15 years.
- Thread starter
- #19
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
So what protects the cam from the carbide?
GregP
Major
There are NO Reno "racing" engines with pretty much zero modifications. The stock engines have pretty much zero mods, but the dedicated racing engines do not.
All the top race engines are modified. All the hot Merlin engines run Allison G-series rods because the stock Merlin rods won't take 3,500+ HP. They carefully balance the crankshaft and rods / piston to within a very small weight difference ( a few grams). The valves are cut bigger for more airflow. The ports (intake and exhaust) are polished and smoothed. Everything is checked and made perfect, including intake, exhaust, valves, tops of pistons, etc. Think of blueprinting and balancing a drag racing V-8. Same stuff.
Basically an engine is a air pump. The more air you pump through it, the more power it makes. The adibatic perfect mxiture is around 13.5 : 1 or so for normally asiprated engines and is different for supercharged engines. All the Reno engines are supercharged. Since the cylinders are NOT bored oversize, the only way to pump more air is threefold:
1) Increase the RPM.
2) Increase the intake boost pressure.
3) Increase both the RPM AND the intake boost pressure.
All the true racing engines do one of the three above.
The R-3350 in Rare bear is still an R-3350. That is, it still displaces 3350 cubic inches. At 3,000 HP they run about 3,000 RPM and 60 inches of manifold pressure. At 4,000 Hp they run 70 inches of MP and the RPM is very probably 3,350 tp 3,400, which means they have to gear the prop so the tips don't go supersonic at the prop RPM. For reference, a typical stock R3350 turns at 2,800 RPM tops.
The Merlins typically spin at 3,000 RPm and 61 to 67 inches of MP in stock form. For Reno they can run up to about 140 inches and 3,600 RPM .... but they can't do it for too long. After about 2 laps, the Merlins at high power get heat saturated and must be reduced in power or they will blow up. All the Merlins use ADI (anti-detomation injection fluid) that is usually water-methanol for cooling. ADI works and can make more power until the water/alcohol is used up; then you have to reduce power or the engie will fail due to excessive heat. Almost all have spray bar. It is literally a tube with holes in it to spray water directly onto the radiatior core for better heat transfer. It is a total loss system.
Some Merlins and even air-cooled radials use a boil-off system for the oil, or in the case of The Galloping Ghost, for both oil and engine cooling. The radials typically use a boil-off for the oil only since they don't HAVE coolant. This type of system runs metal tubes through a water (or glycol) tank and transfers heat from the coolant to the boil-off liquid. When the boil-off liquid gets hot enough, it produces steam. The steam increases the pressure in the boil-off tank. When the pressure exceeds the pop-off valve setting, the steam is vented overboard via an exhaust port. Boil-off planes can fly until the boil-off liquid is used up as steam, and then it will simply quickly overheat and fail. It is important NOT to do that in a boil-off application. Definitely range-limited, even at slow-cruise power.
The main reason to USE a Boil-off system is that it eliminates the drag of an oil cooler or the oil cooler AND radiator. You still have to exhaust the steam, but the drag of the coolers is eliminated. That equals more HP for propulsion becasue you are not using any HP to overcome the cooling drag. Less drag equals more power for speed.
All the top race engines are modified. All the hot Merlin engines run Allison G-series rods because the stock Merlin rods won't take 3,500+ HP. They carefully balance the crankshaft and rods / piston to within a very small weight difference ( a few grams). The valves are cut bigger for more airflow. The ports (intake and exhaust) are polished and smoothed. Everything is checked and made perfect, including intake, exhaust, valves, tops of pistons, etc. Think of blueprinting and balancing a drag racing V-8. Same stuff.
Basically an engine is a air pump. The more air you pump through it, the more power it makes. The adibatic perfect mxiture is around 13.5 : 1 or so for normally asiprated engines and is different for supercharged engines. All the Reno engines are supercharged. Since the cylinders are NOT bored oversize, the only way to pump more air is threefold:
1) Increase the RPM.
2) Increase the intake boost pressure.
3) Increase both the RPM AND the intake boost pressure.
All the true racing engines do one of the three above.
The R-3350 in Rare bear is still an R-3350. That is, it still displaces 3350 cubic inches. At 3,000 HP they run about 3,000 RPM and 60 inches of manifold pressure. At 4,000 Hp they run 70 inches of MP and the RPM is very probably 3,350 tp 3,400, which means they have to gear the prop so the tips don't go supersonic at the prop RPM. For reference, a typical stock R3350 turns at 2,800 RPM tops.
The Merlins typically spin at 3,000 RPm and 61 to 67 inches of MP in stock form. For Reno they can run up to about 140 inches and 3,600 RPM .... but they can't do it for too long. After about 2 laps, the Merlins at high power get heat saturated and must be reduced in power or they will blow up. All the Merlins use ADI (anti-detomation injection fluid) that is usually water-methanol for cooling. ADI works and can make more power until the water/alcohol is used up; then you have to reduce power or the engie will fail due to excessive heat. Almost all have spray bar. It is literally a tube with holes in it to spray water directly onto the radiatior core for better heat transfer. It is a total loss system.
Some Merlins and even air-cooled radials use a boil-off system for the oil, or in the case of The Galloping Ghost, for both oil and engine cooling. The radials typically use a boil-off for the oil only since they don't HAVE coolant. This type of system runs metal tubes through a water (or glycol) tank and transfers heat from the coolant to the boil-off liquid. When the boil-off liquid gets hot enough, it produces steam. The steam increases the pressure in the boil-off tank. When the pressure exceeds the pop-off valve setting, the steam is vented overboard via an exhaust port. Boil-off planes can fly until the boil-off liquid is used up as steam, and then it will simply quickly overheat and fail. It is important NOT to do that in a boil-off application. Definitely range-limited, even at slow-cruise power.
The main reason to USE a Boil-off system is that it eliminates the drag of an oil cooler or the oil cooler AND radiator. You still have to exhaust the steam, but the drag of the coolers is eliminated. That equals more HP for propulsion becasue you are not using any HP to overcome the cooling drag. Less drag equals more power for speed.
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