Engine build up

[FLYBOYJ]

Exactly!

[Bug_racer]

Originally Posted by Shortround6

Building a totally modern engine would allow a good portion of your ideas. Modifing an existing engine to a very large extent would be almost as expensive (if not more so).
However there are problems that the designers were aware of even back then (WW II).
one is cylinder size. THE flame front in the cylinder is only going to move at a certain speed from the source/s of ignition. This tends to limit the size of the cylinder in relation to the RPM.
Large diameter cylinders are also harder to cool. for instance going from the 5.4in bore of the Merlin to the 6in bore of the Griffon ment an increase of 23.4% in volume for every in of stroke but only an 11.1% increase in cylinder wall area.

Dont these planes run dual spark plugs per cylinder ? That would help will flame travel .
I mentioned the oil squirters . These have been proven succesful on many cars . You'll find Porsche is starting to build N/A motors running 12:1 compression ratios to run on 98 octane and VW/Audi uses 10:1 Turbo cars running FSI . When the engines were built in ww2 what was the average compression ratio ? around 7:1 ?



As far as trying to cool some of these aircraft I believe ( and I could be wrong here) that some of the planes actually carry water tanks to allow them to spray a water mist onto their radiators to assist in cooling. THe heat transfer in the water evaporation upping the cooling ability of the radiator. Apparentl the extra cooling allows enough more power to be used to offset the weight of the tank and water.

Its not all about cooling , its about getting it to the optimum operating temperature and keeping it there . if you have control over timing of every cylinder individually and fuel being metered and lambda being measured on each cylinder as it leaves your gonna know exactly whats happening . Having 1 or 2 carburettors for 12 cylinders your gonna have different runner lengths for every cylinder and each cylinder will receive a different amount of fuel at a different velocity . Its inefficient although simple . dumping more fuel will cool the chamber but the negative is you loose power.

Did you know that P&W had over 3000hrs of Bench testing on the R-2800 before they ever but one in a test mule aircraft?
Or that it is claimed that the only things in common between an "A" series R-2800 (1850hp take-off) and a "C" series R-2800 (2100hp take-off) were the bore, stroke and starter dog?

Modern systems (fuel injection and ignition) might go a ways in solving some of the problems that some of those old engines had but it would require quite bit of testing to sort them out and prove their reliability.

EFI is far more reliable than a 60 year old system ! The technology has reached new heights and is progressing at an astonishing rate . Have a look at the winning Le-mans Audi . Its a diesel , yes a diesel can win a race . Why , cause they threw away the old pump set up and converted it to EFI . The only difference between the Diesel engine and a new TFSI car is the spark plugs . They both even sound the same !

Most race teams (cars, boats, whatever) will tend to stick with what they know works unless A, they start losing big time. B. something promises them a big advantage. C they have a lot of extra money and time to play with something new.

I dont think the air races are somewhere where you see cutting edge technology , I havent seen any plane specs but at this day in age they should be flying a lot faster than the speeds they had in WW2

As to certain planes doing well in the races it is also interesting to go back and look at some of the post war racers. There was one P-39 with about 9 ft clipped from the wings in one race. The pilot later confessed that whatever he gained on the straights he lost in the turns.

One thing I dont know much about is airframe design . I know race cars fairly well but this Id need a lot of help with

A successful air racer has to accelerate and take off quickly, go fast in a straight line, be able to turn without bleeding off more speed than his competitors, and be able to do it for the duration of the race.

I think having big hp thats always available will help the most in an air race . Sure it might need fine tuning but I can guarantee at least 10% more power for 5% less fuel as a min .

There was a time until the late 1990s that on a drag car a carburettor would outflow in HP a modern efi system . Every year stand alone units were upgraded and not so long ago the carburettor was made redundant in the hp contest . EFI will give more power reliably for less fuel . The throttle response is also faster and there are less moving mechanical parts to fail . How many forms of motorsport still use Carburettors / mechanical injection as a primary fuel delivery system ?

[Bug_racer]

Originally Posted by vanir

Dang my stupid connection bumped me and lost my post. Oh well the gist of it was as FlyboyJ alludes, you're talking about spending $45K on what amounts to improving output on a 3500hp motor by something like 150hp but for nicer manners and less trouble, where you can do some aerodynamic sorting for more like $3K and that's as good as bolting on 300hp.

Don't underestimate the effectiveness of old tech like say slide valve carbs over ECU injection because when setup right they perform just as good. The laptop tuning facility is a nice luxury and beats six months sorting needle profiles but if you've got intuitive crew you find old tech is competitive with new tech on the track at about a quarter the price. I did in auto racing. I'll admit I always wanted to switch over to an ECU/injection setup but it wasn't worth any extra power, just a lot less mucking around.

You might be onto something with fresh tactics like turbos over mechanical blowers but safest bet is again like FlyboyJ says and find out the reasons why current crews are using what they're using first. No point spending a ton of money to learn what they already know if you can just ask.

I use to play with carburettors years ago . I got over it very quickly . Driving around with a box of jets and emulsion tubes , air density meter and vacuum plunger . Its all good when your young but when you get older you want to make things easier . As I mentioned earlier efi has overtaken carburettors .The new stand alone units have self tune which automatically tunes itself to the engine . it doesnt search for peak power but it does provide a safe tune with minimal work . With EFI you can log data , you can make changes to the engine at particular points around the track . At the end of the day your trusting a computer that can make a decision far quicker than you can . By the time you even see the first warning light the ECU can lower the boost / retard the timing and add watermeth too cool the combustion chamber down .

Id love to build an engine and have it tuned . Id never get it on any dyno cause I havent seen one that is rated for over 2500 hp . But who would build me an airframe , or better yet , who would be the mad pilot to test out the missile !

[beaupower32]

Originally Posted by Bug_racer

How many forms of motorsport still use Carburettors / mechanical injection as a primary fuel delivery system ?

NASCAR is one.

[FLYBOYJ]

Originally Posted by Bug_racer

Id love to build an engine and have it tuned . Id never get it on any dyno cause I havent seen one that is rated for over 2500 hp . But who would build me an airframe , or better yet , who would be the mad pilot to test out the missile !

There are test cells that could support recips that put out well over 3000 hp. As far as finding a pilot, there would plenty of takers as what you're proposing isn't really that radical and it isn't going to push any racer that more faster than what you're seeing right now.

[Bug_racer]

Originally Posted by beaupower32

NASCAR is one.

Top Fuelers are another (they dont care how much fuel they use as long as it doesnt compression lock up !)
Nostalgia drags ??
Reno Racers

Thats all I can think of . Everyone else can use EFI and choose to do so

[Bug_racer]

Originally Posted by FLYBOYJ

There are test cells that could support recips that put out well over 3000 hp. As far as finding a pilot, there would plenty of takers as what you're proposing isn't really that radical and it isn't going to push any racer that more faster than what you're seeing right now.

Maybe in the US but I doubt they will have anything here in Aus .

Yeah your right its not revolutionary , just an evolution of what was on before . With the right set up I do see the planes going faster . Turbo's are far more efficient than superchargers .

Remember the old days of F1 technology in the 80s where they were running 1000hp+ out of turbocharged 1.5l engine ? That technology is readily available and is so much more flexible these days .

I should start my own race team and build a plane , maybe call it evolutionary bandit or something

[FLYBOYJ]

Originally Posted by Bug_racer

Maybe in the US but I doubt they will have anything here in Aus .

Yeah your right its not revolutionary , just an evolution of what was on before . With the right set up I do see the planes going faster . Turbo's are far more efficient than superchargers .

Remember the old days of F1 technology in the 80s where they were running 1000hp+ out of turbocharged 1.5l engine ? That technology is readily available and is so much more flexible these days .

I should start my own race team and build a plane , maybe call it evolutionary bandit or something

You can with enough time and money, but remember, its been done before.

Scaled Composites Pond Racer - Wikipedia, the free encyclopedia

And again, even if you got 6000 hp out of an aircraft engine, it doesn't mean you're going to much faster than what's already been seen at Reno. I'm in the jet class and the guy who took first is just short of reaching critical mach at 540 mph. A recip with a big propeller out there isn't going to see much more than 530 mph

[Bug_racer]

Originally Posted by FLYBOYJ

You can with enough time and money, but remember, its been done before.

Scaled Composites Pond Racer - Wikipedia, the free encyclopedia

And again, even if you got 6000 hp out of an aircraft engine, it doesn't mean you're going to much faster than what's already been seen at Reno. I'm in the jet class and the guy who took first is just short of reaching critical mach at 540 mph. A recip with a big propeller out there isn't going to see much more than 530 mph

Interesting link . Would such a light plane pass under todays rules ?

What they did was completely different and it didnt work . The reason for using modern day electronics would be too make things simpler and more effective with fuel on board . This looked like a lot of work and on a knifes edge ! Im suprised by the engine choice . I dont think they really took into account the nature of this particular engine and its drawbacks . If I was to use an automotive engine I would def test it in the car for extended periods first ! Not to mention the ECU would have been very primitive back then , there was no stand alone units back then . Completely different train of thought

You mention 530mph as the limit . Is this the record for a piston engine plane ?

[Skip M]

Originally Posted by Bug_racer

who would be the mad pilot to test out the missile !

I always thought the hardest part is finding someone who will give me the money to build it.

[FLYBOYJ]

Originally Posted by Bug_racer

Interesting link . Would such a light plane pass under todays rules ?

What they did was completely different and it didnt work . The reason for using modern day electronics would be too make things simpler and more effective with fuel on board . This looked like a lot of work and on a knifes edge ! Im suprised by the engine choice . I dont think they really took into account the nature of this particular engine and its drawbacks . If I was to use an automotive engine I would def test it in the car for extended periods first ! Not to mention the ECU would have been very primitive back then , there was no stand alone units back then . Completely different train of thought

You mention 530mph as the limit . Is this the record for a piston engine plane ?

I don't know what the weight of the Pond racer was I would guess it wouldn't qualify today. As far as testing of the engine and the decision to go with that engine, again I wouldn't know but coming from Rutan, be rest assured that some thought was put into the engine choice. Had it not crashed who knows how it would have matured?

Why would you test it in a car? You will not see the degree of variable RPM in an aircraft as you would see in a car as well as the engine speed if you run with a transmission as opposed to a propeller gearbox, one of the reasons why it could be difficult to put aircraft engines in cars and visa versa.

The record around the Stead course is about 528 mph for a recip. Much faster and the airframe and propeller will start hitting critical mach and one or both will start coming apart due to compressibility, so you see all the HP in the world will limit you at Reno in the Unlimiteds.

I do know there is also course rules that dictate how fast and high the races can fly and this is done based on a 'scatter pattern" should an aircraft crash. These rules were made by the FAA.

In all classes I don't think you're going to see any recip go much faster thjan 530 and the jets go faster than 540 unless there are rule and course changes, and I could tell you that too will not happen.

[Bug_racer]

Originally Posted by Skip M

I always thought the hardest part is finding someone who will give me the money to build it.

You just build it over 10/15 years

[Bug_racer]

Originally Posted by FLYBOYJ

I don't know what the weight of the Pond racer was I would guess it wouldn't qualify today. As far as testing of the engine and the decision to go with that engine, again I wouldn't know but coming from Rutan, be rest assured that some thought was put into the engine choice. Had it not crashed who knows how it would have matured?

Why would you test it in a car? You will not see the degree of variable RPM in an aircraft as you would see in a car as well as the engine speed if you run with a transmission as opposed to a propeller gearbox, one of the reasons why it could be difficult to put aircraft engines in cars and visa versa.

The record around the Stead course is about 528 mph for a recip. Much faster and the airframe and propeller will start hitting critical mach and one or both will start coming apart due to compressibility, so you see all the HP in the world will limit you at Reno in the Unlimiteds.

I do know there is also course rules that dictate how fast and high the races can fly and this is done based on a 'scatter pattern" should an aircraft crash. These rules were made by the FAA.

In all classes I don't think you're going to see any recip go much faster thjan 530 and the jets go faster than 540 unless there are rule and course changes, and I could tell you that too will not happen.

Never set limits on something that really has none . It just makes men strive harder !

Looking into building a plane . Cost is huge , but will do it over long term . Will keep you posted on findings

[engguy]

The old aircraft engines had and have most of the so called new tech stuff mentioned, way before it became known in the car world. It took pretty much 50 plus years for the automobile performance world to catch up with what was the norm in the large recip aircraft engine world in and before World war 2. Even things that you mentioned like changing ignition timing per cylinder was and is done on some large engines, but the old fassioned way, mechanically. I agree everything can stand some improvement, I have some really good ideas, and maybe someday I can put them into operation. Oh by the way aircraft engines were on NOS in the war days, so nothins new under the sun. Just like turbos and after cooling, when did that hit the cars and trucks of today? Thats a late 1940's and early 1950's deal in aircraft, it maybe sooner than that?
As far as EFI and all that fun electronic stuff, yeah its nice when its working right. I know of many cases where the good old carb does as good or better. Turbo's over mechanical blowers? A radial needs that impeller to help distribute fuel air, a turbo will negate the power demand of the blower and its been done already in large recip aircraft, I'm not sure what the racer guys are doing though. They tend to keep the weight down and keep it simple I would guess.
I have an idea to get close to 2 times the hp they are getting now, the bad part is lots of things would need to be changed to do it. You mentioned materials, I fully agree. Yeah it would cost some big $ to extract some big HP.

For got to mention that big problem out front the big fan. So how do you get around the effciency problems there? If you make the HP how do you put it to good use?

[FLYBOYJ]

Originally Posted by Bug_racer

Never set limits on something that really has none . It just makes men strive harder !

Looking into building a plane . Cost is huge , but will do it over long term . Will keep you posted on findings

I wait with baited breath.