Challenge: Beat Strega

[Victor Bravo]

Go get 'em Ross !

IMHO get down to Mojave ASAP and have lunch with Ralph Wise. Very high quality individual, with many years of air race and aircraft building experience, experienced engineer, and can tell you what does and does not work. Very few people have the ability to discuss air racing from ALL relevant perspectives, designer, builder, tuner, driver, team owner. He's earned the ability to justify a huge ego and yet he's the most gracious and approachable person you could imagine.

And he's done design and development and construction on a V8 powered small raceplane.

 

[rv6ejguy]

I'm friends with many people in the Reno racing world and the instigator is pulling together many experienced minds for this project. I'm just bringing my EFI, engine and turbocharging backgrounds to the project to assist in those aspects. This will certainly be a team project.

My forays to the US are done for this year now. Super busy with orders and new system development again for quite some time. I'd love to get to Mojave next year though if time permits. There's so much brain talent there to learn from.

 

[poormansairforce]

Top Fuel engines make 10,000 hp and have a lifespan of five seconds. Thats not what I'm talking about. The link I posted earlier shows a used, junkyard 4.8 LS engine boosted to make over 1200 HP, which it survived many dozens of dyno runs. Does that equate to 15 minutes of life on the course, probably not. But it does allow one to extrapolate that to the GM Performance LS-X block. The LS-X is the big brother to the entire LS family and is designed for big inches and a lot of internal stress. Load the block with high quality components, top it with some good heads, tie it all together with premium fasteners, and throw 30+ pounds of boost at it... I believe you will get your 15 minutes.

All of it is a credit card away.

And if you drop the compression ratio to 5:1 you get a virtual doubling of chamber volume at TDC which doubles the cylinder pressure left at 90° crank throw. Basically, a 1000 ci engine boosted to 15 psig. Run it at 4500 RPM and you have tons of torque and as well as longevity. For comparison, at 3:1 CR it would act as a normally aspirated engine 3 times the size with huge torque at low rpms but would need some special starting procedures and maybe staged turbochargers. This is the way forward for efficient direct drive engines that retain their reliability since they could be designed so the cylinder pressures/stresses are not greatly affected.

 

[rv6ejguy]

No need for radical changes to existing engines. A 900 inch V8 with 9 to 1 CRs running at 6500 rpm would easily make right around 3000hp at 60 inches.

 

[Aesquire]

Drag racing engines are like rocket engines of the 1930's. They live very short but exciting lives, and are junked or rebuilt to use again. ( the Walther engine in the Me-163 & the RATO units of the now JPL were the first re-usable engines I recall )

So don't look to drag racing. Look to NASCAR, or F1. Engines built for 500 miles, not 1/4 of 1.

Keep in mind it took Rolls Royce YEARS to get the Merlin to pass a 100 hour military test, and that at 790 hp.

 

[Himat]

These airframes are massively draggy compared to what's in sport class now. I bet you'd need well over 4000 hp to run with Strega in Unlimited.

I will not question your assessment, rather agree. I did look at those airframes because they fit somewhat with the minimum weight requirement. To me those airplanes look like the ones that today most closely resembles the WW2 piston engine fighters. Also by the numbers they look similar, but racing them they probably then need as much power as the old racers.

A clean sheet design may have lower drag, but that 4500lbs empty weight requirement make for a large airplane. Costly to develop and costly to race. If sizing was free a smaller, cheaper airframe competitive airframe could be developed.

 

[Toobuilder]

Drag racing engines are like rocket engines of the 1930's. They live very short but exciting lives, and are junked or rebuilt to use again. ( the Walther engine in the Me-163 & the RATO units of the now JPL were the first re-usable engines I recall )

So don't look to drag racing. Look to NASCAR, or F1. Engines built for 500 miles, not 1/4 of 1.

Keep in mind it took Rolls Royce YEARS to get the Merlin to pass a 100 hour military test, and that at 790 hp.

There are many different flavors of drag racing engines - from the 5 second lives of Top Fuel to the daily driver/bracket cars that "might" look at a set of rings every other season. Keeping parts alive from an internal stress standpoint is not hard regardless of their application. A connecting rod that can survive the internal stress of 2000 HP in a drag race will also generally do so in an endurance event. The main focus is on being able to stabilize temps for sustained periods. Keep temps under control and keep the internal stresses within the design limits and the engine will last. The wear items will certainly see accelerated lifespans at extreme power levels, but bearings and rings are pretty easy to change between races.

In reference to the 100 hour contract life on the RR Merlin, consider that there are now passenger cars for sale (with a warranty) that make that kind of absolute power, and are much more highly stressed from a power density standpoint.

 

[Toobuilder]

I will not question your assessment, rather agree. I did look at those airframes because they fit somewhat with the minimum weight requirement. To me those airplanes look like the ones that today most closely resembles the WW2 piston engine fighters. Also by the numbers they look similar, but racing them they probably then need as much power as the old racers.

A clean sheet design may have lower drag, but that 4500lbs empty weight requirement make for a large airplane. Costly to develop and costly to race. If sizing was free a smaller, cheaper airframe competitive airframe could be developed.

Screw the minimum weight requirement. As soon as the Sport class runs faster than the "Unlimited" frontrunners, they become the draw. ESPECIALLY if they have V-8's in them. The NASCAR crowd will start to take notice then, I expect.

 

[Hot Wings]

Some possible candidates to explore:

* That big engine sound. F1 has its tortured shriek, NASCAR thunders, but only Reno Unlimiteds have the throaty baying-at-the-moon howl of the Merlin.

You want thunder? I wanna see/hear/feel helicopter pylon racing. :gig:

 

[BJC]

Screw the minimum weight requirement. As soon as the Sport class runs faster than the "Unlimited" frontrunners, they become the draw. ESPECIALLY if they have V-8's in them. The NASCAR crowd will start to take notice then, I expect.

I flew around Atlanta International Raceway once, and no one noticed - thankfully.


BJC

 

[bmcj]

From another thread, but since this one has morphed into an alternate class thread:

Hey, I've got an idea for the next class of racers at Reno...

(drum roll please)

JB-9 or JB-10 jet backpacks. They already have something like a 10 minute endurance. Set up a short course to keep them within sight of the spectators and have at it!

(And if you want even more variety, try to revive the old Rocket Racing League with a pylon class designed for them.)

 

[Swampyankee]

Scale up the AR-6 Formula One racer to 200% scale, put retaractable tricycle gear (in the FUSELAGE like an F-104), and put a large electric motor in it with some sort of chemical fuel cell in it to drive the motor. The reaction of the fuel cell might be able to qualify as internal combustion.

If a fuel cell counts as internal combustion, so does a gas turbine. Take a stock turboprop, and turn up the wick.

 

[wwalton]

You want thunder? I wanna see/hear/feel helicopter pylon racing. :gig:

I saw that demonstrated at the Phoenix 500 air races around '95 at the old Williams AFB. They had 4 helicopters line abreast in a hover and waved a flag to start. I've never seen helicopters do that and the angles seemed extreme at the start. I noticed that the following helicopters all stayed above the path of the leader. I think the NOTAR won, but it's been a while.

 

[wwalton]

Of course I have another alternate class concept too. Take the Formula One rules and their race horse start and make an electric class. 70 Kw motors and whatever batteries you like. With the gigafactory there, maybe the air races could cash in on some of that Tesla money.

I know they would be quiet and not as exciting to the public, but the formula one fans may like the tech.

Many leading race car organizations are adding EV classes and I think it's because it draws in the next generation of fans.

 

[Aesquire]

In reference to the 100 hour contract life on the RR Merlin, consider that there are now passenger cars for sale (with a warranty) that make that kind of absolute power, and are much more highly stressed from a power density standpoint.

Can't argue with any of your post. I'm in the planning stages for a Hot Rod Magazine Drag Week car now. 1000 miles, 4 tracks, 5 days of drag racing. ( although only one run a day is required ) Since we don't plan on winning, other than finishing, which is the Big win, I've been looking hard at how much power is affordable and can stay alive in the hard knock world of driving on the roads. ( the Fast guys are running in the 6 second range.... that was faster than Top Fuel when I first went drag racing )

My point is the "1000 hp" figures often quoted about drag racing engines are usually for a few seconds. The Endurance racers are using a lot of the same parts, but are tuned a bit more conservatively. ( but, amazingly, not that much )

That's why my earlier question, are you flying there, or is it a trailer queen? How close to boom do you want to run?

I think it's pretty well established that it's tough to meet the existing rules without a LOT of power. The minimum weight rule keeps you from making an Improved Bearcat that could beat a surplus one easily.

 

[mcrae0104]

That's why my earlier question, are you flying there, or is it a trailer queen?

Just because you can push 1,000 hp or 450 kt doesn't mean you have to just to get to the race. Plenty of racers get there without a trailer.

 

[Toobuilder]

So that brings up an interesting point for discussion: What is the LIMFAC of a drag race/dyno queen engine vs. an endurance engine? I believe its thermal stability. A 10,000 HP top fuel hemi can get through 4 seconds of power before thermal inertia has even caught up. This is kind of a brute force solution. However, an endurance engine needs to get to temp and then stabilize for the duration of the event. If the rotating assembly and the head gasket seal can withstand the forces of max output for say, 1 minute, then they should be good for 20. But the cooling system has to be capable of taking control and stabilizing the whole system forever.

And no, I dont think this level of competition expects the "race" engine to drag the airplane around the country from race to race. It should get a "ferry" engine at the least, and meet the NASCAR style tractor trailer at the event thats filled with several race only engines, spares and a full machine shop. This is racing, not a weekend poker run.

 

[Direct C51]

I saw that demonstrated at the Phoenix 500 air races around '95 at the old Williams AFB. They had 4 helicopters line abreast in a hover and waved a flag to start. I've never seen helicopters do that and the angles seemed extreme at the start. I noticed that the following helicopters all stayed above the path of the leader. I think the NOTAR won, but it's been a while.

[video=youtube;y2si4h06ZrE]https://www.youtube.com/watch?v=y2si4h06ZrE[/video]

 

[mcrae0104]

But the cooling system has to be capable of taking control and stabilizing the whole system forever.

Maybe not forever, but for 10 minutes anyway. Are you familiar with the boil-off systems used by some Unlimited racers?

 

[gtae07]

I flew around Atlanta International Raceway once, and no one noticed - thankfully.

I was so tempted to do that when I was first working on my license. I did a lot of pre-solo training over at Tara field next to the track because the pattern wasn't as busy and wanted to try to at least try to dip low between the stands (at the time both runways used a left pattern and landing on 24 would bring you over the track if you flew a wider pattern). 9/11 happened a couple days before I was going to solo and put a hard stop to those plans.