A shameless image thread for the enginephiles

[wuzak]

Can I ask why engines like the V12 Merlin are upside down?

The Merlin (PV12) was originally going to be inverted, but after consultation with the airframe manufactures it reverted to an upright V-12.

[wuzak]

I've seen the 20ish litre RR V12 (4 blade prop) in a WW1 Bristol fighter being hand started by the Armstrong method
man 1 pulling the prop blade with 1 arm, man 2 pulling with 1 arm man 1's other arm, and man 3 pulling man 2's other arm

The Bristol Fighter was primarily powered by the Rolls-Royce Falcon. It was a smaller version, of the Eagle (14.2l vs 20.3l).

RR got the job (of improving on the Curtiss V12 for the British nation) because Napier refused it
the Lion designer Rowledge had already left Napier for RR

Rowledge left Napier for Rolls-Royce a few years before that.

Rolls-Royce were basically out of the aero engine business when the government came calling for a British engine as good as, or better than, the Curtiss D12, which Fairey was seeking to manufacture under licence (they had imported them and named them Fairey Felix).

Rolls-Royce developed the F, which would develop into the Kestrel, and the Eagle XVI. The Eagle XVI bore no relationship to their earlier Eagle series of engines, being an X-16 of 19.4l.

The Eagle XVI had two banks offset from the others (top from bottom IIRC) and used fork and blade rods for each pair of cylinders. I don't believe it was supercharged (early Kestrels weren't either), and the prototype was certainly not flightworthy.

Henry Rolls was said to have preferred the Eagle XVI, but the airframe manufacturers preferred the F (and since they would be the ones buying the engine, they won).

and later Napier produced a Merlin rival that had 12 independent cylinders

They did? What was its name?

smaller than the Lion the Kestrel ran on 70ish octane and later (Peregrine) was rated at 875 hp on 80 octane
ran for hundreds of hours not hundreds of seconds

Early Kestrels ran on fuel with octanes in the mid 70s. The early MkIs were unsupercharged, but later Is were medium or fully supercharged (refers to the amount of boost).

By the Kestrel Mk.V, the engines were running on 87 octane.

The Peregrine I was rated at 885hp at 3,000rpm on 100 octane fuel. Interesting to note that the Vulture, which had the same bore and stroke as the Peregrine, was allowed 3,200rpm before bearing problems required them to be detuned.

Like most aero engines, the peak power 885hp was a short duration limit. Maybe 5 minutes, 15 minutes at most.

[noice]

So here’s the deal.
If they were liquid cooled heads they would have that area machined out and then closed off to remove heat from around the exhaust valves and ports.

Because they have no cooling other than from oil and from the cooling effects of the Methanol they hollow out that area to reduce the heat sink effect between the exhaust ports. They want the heat to just go out the exhaust and not build up in the head.
It’s believed this helps prevent cylinders going out.

The welcomed side effect is a slight reduction in weight. Very slight.

Just a question to see what you know, what do they spray the throttle blades with after the burnout?

Also on a methanol engine what is done on the fuel side to warm up the engine in the pits?

If you mentioned nitro motors in your post then your theory would be possible.

However you say methanol, which if you have run in any kind of high pressure mechanical nozzle injected K-valve controlled application you would know that in order for the engine to not bog down from acceleration there has to be excessive, and I mean very excessive fuel to the engine at idle. Nitro and methanol guys spray DE-ICER into the throttle blades to keep them from getting stuck. You can see ice formation on the blower housing at idle.

On a water cooled methanol engine at idle the engine must be leaned out if you want the engine temperature to come up normal temperatures. If you sit with full fuel to the engine, it will take forever to warm up.

One last thing, last thing a top fuel crew chief does on the engine before they stage the car is set the fuel flow to high (stop returning most of the fuel to the tank).

The average temp of exhaust while on the starting rev limiter is less than 350F. The highest it gets is 1900F or so, with and average of 1700F. The fwd cylinders always run leaner than the back. That is one reason they moved the blowers forward is to try and get a better distribution of air throughout the engine.

Fuel keeps those engines cool, most of the fuel injected above the blower is to help it seal and stay cool.

[MrPotatoHead]

Noice - you are right I meant to say Nitro not Methanol. It’s been a long week. Nitro and Methanol are very different beasts.

[johnny comelately]

Can I ask why engines like the V12 Merlin are upside down?

The Merlin (PV12) was originally going to be inverted, but after consultation with the airframe manufactures it reverted to an upright V-12.

Thanks for that

[johnny comelately]

So here’s the deal.
If they were liquid cooled heads they would have that area machined out and then closed off to remove heat from around the exhaust valves and ports.

Because they have no cooling other than from oil and from the cooling effects of the Methanol they hollow out that area to reduce the heat sink effect between the exhaust ports. They want the heat to just go out the exhaust and not build up in the head.
It’s believed this helps prevent cylinders going out.

The welcomed side effect is a slight reduction in weight. Very slight.

Just a question to see what you know, what do they spray the throttle blades with after the burnout?

Also on a methanol engine what is done on the fuel side to warm up the engine in the pits?

If you mentioned nitro motors in your post then your theory would be possible.

However you say methanol, which if you have run in any kind of high pressure mechanical nozzle injected K-valve controlled application you would know that in order for the engine to not bog down from acceleration there has to be excessive, and I mean very excessive fuel to the engine at idle. Nitro and methanol guys spray DE-ICER into the throttle blades to keep them from getting stuck. You can see ice formation on the blower housing at idle.

On a water cooled methanol engine at idle the engine must be leaned out if you want the engine temperature to come up normal temperatures. If you sit with full fuel to the engine, it will take forever to warm up.

One last thing, last thing a top fuel crew chief does on the engine before they stage the car is set the fuel flow to high (stop returning most of the fuel to the tank).

The average temp of exhaust while on the starting rev limiter is less than 350F. The highest it gets is 1900F or so, with and average of 1700F. The fwd cylinders always run leaner than the back. That is one reason they moved the blowers forward is to try and get a better distribution of air throughout the engine.

Fuel keeps those engines cool, most of the fuel injected above the blower is to help it seal and stay cool.

If you were talking about nitro, there is NO (starting rev limiter) two step

[J.A.W.]

T-C, Kestrel was of 22 litre capacity, Lion was 24.. really not so much - in it..

R-R went to 36 litres for their type R ( and Lion designer Rowledge had to revise it, with master/slave rods),
& later using the same archaic under-square B x S dimensions for the 'improved Merlin' style, Griffon..

R-R never seemed to get their own atypical designs to function properly ( viz: Vulture) but did well
with developing the nuts off their conservative V12's - to good profit, even if the Griffon was also
well shaded by the ( also 36 litre capacity) Halford/Tryon designed Napier Sabre - as a fighter mill..

The way you put things, it would seem like Napier invented the master and slave rod. Which they probably
didn't. It was, of course, a necessity.

The Rolls-Royce R was a racing version of the Buzzard.
The Buzzard, itself, was essentially a 6/5 scale of the Kestrel.

The Buzzard was an 800hp engine in the late 1920s, but didn't find many buyers. Possibly because it was too powerful for the airframes at the time.

To change into the R, the Buzzard was strengthened substantially, ,and a giant double sided impeller fitted.

For the 1929 Schneider races the R retained fork and blade type rods. The engine had grown by about 1,100hp compared to the Buzzard.

For the 1931 race the R was upgraded again. It was a relatively late decision to contest the Schneider
Trophy that year, as the government had withdrawn financial support after the stock market crash. Private funding was found in January 1931, after which government support was again given.

The R's power increased to 2,300hp from 1,900hp, and reliability issues were causing problems, mainly with
the big end bearings. These may have been of the solid metal kind, rather than the steel backed bearings developed by Allison in the US (Rolls-Royce entered a licence agreement with Allison to produce the steel backed bearings at around that time). Because of the short development time, they reverted back to the master and slave rod arrangement, which earlier Rolls-Royce engines, such as the Eagle and Falcon, had used.

For the air speed record attempt the engine was further boosted, producing as much as 2,900hp in 1931.

A Gloster VI seaplane with Napier Lion set the world air speed record at 336.3mph on 10 September 1929.
The Supermarine S6, with Rolls-Royce R, reset the record at 357.7mph 2 days later.

The S6B would add nearly 50mph to the record, at 407.5mph.

Later in the `30s, when Nazi-sponsored fighter-based landplanes had bested the speeds achieved by
the racing sea-planes, R-R & Supermarine put together a 'Speed Spitfire' - a carefully smoothed
Spitfire powered by a hi-po Merlin, using the lessons R-R learned in making power, with the R-type.


However, they were cut-off at the knees - with the 460+ mph achieved by Heinkel's new He100 prototype..





The Brits weren't quite out of the game just yet though,
& with a Napier-powered Railton newly holding the World Land-Speed Record,
Napier put up one of their new 2,000+ hp Sabre engines - to power the Heston racer... & then came the war..




Amazingly, the sleek Napier-Heston was test-flown - but alas only had one abortive flight, suffered a heavy
landing & was not repaired.. yet the Sabre mill from that wee bird - was duly fitted to a service Typhoon
fighter ( & I'll bet the Wingco Flying scored that one personally, with its specially hand-fettled mill!).

[Tommy Cookers]

the He 100 was not a prototype of anything militarily useful as ...
it had surface (ie vapour-phase) cooling - presumably super vulnerable to gunfire
the record breaker had a special tiny wing and a grossly overrevving 3100 rpm 2770 hp engine with a 30 min life
its oil was cooled by surface cooling on the tailplane - said to use methanol as the coolant

Heinkel's record (13 min airborne 2 passes each way over a 3 km course) was beaten by another 'prototype' that wasn't
the Messerschmitt 209 - 'it glides like a piano' - that was then renamed 109R
this also had vapour phase cooling but dumped the coolant rather than attempt to condense and recycle it
469 ? mph on 450 litres of coolant dumped at .5 litres/sec - steam jet propulsion ?

people might look at the Macchi ? seaplane that missed the last Schneider Trophy races but took the record to c. 440 mph

[strad]

If you were talking about nitro, there is NO (starting rev limiter) two step

Unless things have changed the limiter was in the form of a clip that was removed on the start line that acted as a throttle stop during burnouts.

[strad]

Autoweek asked Brown for an inside-the-ropes look at a Top Fuel pass:

T-minus 15 Minutes - Leaving the pit, Off to the staging lanes
“The nitro is really tedious,” Brown says.
Ten minutes before leaving his DSR pit, Brown is pouring 15 gallons of nitromethane into his dragster. A mix of 90 percent nitro/10 percent alcohol must be added carefully just before the run to prevent evaporation. Then Brown grabs his gear and steps to the pit car to ride to the staging lanes.

“That’s where I collect myself. I always have a bottle of cold water to pour on my neck. It wakes me up mentally.
“On the way, I put moisturizing drops in my eyes to limit blinking and put a mouthpiece in to keep from chipping teeth. I’m putting on my helmet, listening to the crew radio last-minute changes -- wheelie bar height or timing-map settings”

The Matco Tools team likes to arrive “about five pairs” before their run. Every time.
T-minus Five Minutes - Loading in, Starting up

A teammate helps Brown with his firesuit, neck collar and gloves. He stretches and steps into the dragster where mechanic Kyle Weekley straps him into a seven-point harness with mountain climber-like thigh straps to prevent “submarining” during deceleration.
“It’s like sitting on the floor with your legs in front of you.”

Brown faces a small steering cane in front of a Racepak digital dash. At his left is a nitrous fuel-flow lever, at right a forward and reverse lever. Crew chief, Brian Corradi keys the radio and says “Ready AB?”

“I flip the ignition and data-logger switches. When I hear the car start, I pull the nitrous lever all the way on. As it runs I move the lever from 110 gallons per minute to about 85-90 gpm.”

A monitor in his firesuit reveals that Brown’s elevated heart rate actually falls below his average resting pulse with the start of the 500 cubic inch 11,000-hp supercharged V8.

“It’s crazy. I just fall into focus mode, trying to think about nothing.”
Antron Brown goes through his final checklist.

T-minus 90 seconds - Burnout & Backup
After 15 seconds idling at 2400-2500 rpm, the signal to roll though the water box is given.
“The fuel lever goes back to full and after three tire rotations through the water, I release the clutch to do the burnout. The engine’s limited by a throttle stop that opens to three-sixteenths of an inch. I hold the burnout to the start line and counter steer as the power and any crown in the track push the rear sideways.

“Then I’ll let the car come to a slow roll on the brakes and just as it’s about to stop, I pull the reverse lever. It’ll go into reverse easily as its moving slightly.”
Brown backs up at an alarming rate. “Our cars are almost 30 feet long. Once I see the 60-foot cone go past my front wheels, I ease on the brake. There’s just a little distance before I cross the starting line.”

T-minus 45 seconds – Staging
Five feet behind the starting line, Brown pauses then creeps forward on the clutch as a crewman waves him to within 6 inches of the staging beam.
“You sit until the crew chief’s done with his final idle adjustment. He’ll put his hand in front of my visor then point forward. I snap my visor down. I take a deep breath, turn the fuel pump full-on, take my foot off the clutch and inch the car into the staging beam with the handbrake.”

With both competitors staged, it’s go-time.

[Maritimer]

If you were talking about nitro, there is NO (starting rev limiter) two step

Unless things have changed the limiter was in the form of a clip that was removed on the start line that acted as a throttle stop during burnouts.

They throttle the fuel pump during burnouts, full throttle and clutch engagement but cut timing and fuel to not burn up the engine

[J.A.W.]

the He 100 was not a prototype of anything militarily useful as ...
it had surface (ie vapour-phase) cooling - presumably super vulnerable to gunfire
the record breaker had a special tiny wing and a grossly overrevving 3100 rpm 2770 hp engine with a 30 min life
its oil was cooled by surface cooling on the tailplane - said to use methanol as the coolant

Heinkel's record (13 min airborne 2 passes each way over a 3 km course) was beaten by another 'prototype' that wasn't
the Messerschmitt 209 - 'it glides like a piano' - that was then renamed 109R
this also had vapour phase cooling but dumped the coolant rather than attempt to condense and recycle it
469 ? mph on 450 litres of coolant dumped at .5 litres/sec - steam jet propulsion ?

people might look at the Macchi ? seaplane that missed the last Schneider Trophy races but took the record to c. 440 mph

Meredith had already demonstrated that effective radiator ducting could utilize the heat exchange to at least balance ( if not provide - a net thrust gain) from liquid-cooled engines, albeit the fastest current
piston-prop racing Mustangs do also use a 'boil-off'/flush frontal area - cooling system...

Macchi used a tandem-twin X2 V12 engine set-up to go ~440 mph, but this was even further away from
being potentially useful for future fighter aircraft..

The Heinkel He 100 was too small to be a practicable fighter for the Luftwaffe, but Kawasaki certainly
applied the technological lessons learned from closely inspecting their imported He 100 machine, & built the
sole Nippon V12-powered (a DB 601-copy, also built by Kawasasaki) fighter, the Ki 61, as a result..

https://www.youtube.com/watch?v=HxnOFsz7Bic

[J.A.W.]

Autoweek asked Brown for an inside-the-ropes look at a Top Fuel pass:



Brown faces a small steering cane in front of a Racepak digital dash. At his left is a nitrous fuel-flow lever, at right a forward and reverse lever. Crew chief, Brian Corradi keys the radio and says “Ready AB?”

“I flip the ignition and data-logger switches. When I hear the car start, I pull the nitrous lever all the way on. As it runs I move the lever from 110 gallons per minute to about 85-90 gpm.”

"Nitrous"?

[strad]

J.A.W; I believe he mis-spoke or AutoWeek got it wrong.. It's too bad Maritimer doesn't read as well as you do.

The engine’s limited by a throttle stop that opens to three-sixteenths of an inch.

[iichel]

Porsche 919 Evo
V4 2.0L
Turbo + GU-H