Hot Heads Btu's to the Max?

Still tingling after Texas Mile handing out speed slips feeling all the heat and various vapors radiating from still throbbing machines that changed phases of once liquid or solid substances in quest for maximum thrill. One gal was so excited trembling she could not be handed a slip !!! Some dudes and dudetts breaking 200 mph almost danced right off their bike at the sight of the slip !!

The volumetric efficiency of an engine is always the highest at its torque peak. Above this rpm, pumping efficiency drops off.

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A round average for airflow vs. hp is 1.5 to 1.6 cubic feet per minute for each hp developed. If you want to work this out in mass flow, a standard cubic foot of air weighs about 0.0765 pounds on a standard 15C day. For example if we have a 4 cylinder engine developing 200hp it would be flowing around 300 SCFM or 23 lbs./min.

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So must burn approximately 11.5 to 12 lb per min total mixture volume per 100 hp or about 150 to 160 cfm mixture per 100 hp

As a round figure, gasoline weighs about 7.2 lbs. per imperial gallon or 6 lbs. per US gallon or 1.586 lbs. per liter and 0.001586 lbs./cc at 15C. So as a rough guide we can say that multiplying and dividing injector flow rates in the 2 popular flow units by 10 gives us a close approximation conversion. A 500cc injector is about a 50 lb. injector.

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Gasoline: US gallon = 115,000 Btu = 121 MJ = 32 MJ/liter (LHV). HHV = 125,000 Btu/gallon = 132 MJ/gallon = 35 MJ/liter

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Regular gasoline = 18,917 BTU/lb (0.0122225 kW·h/g)

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Otto cycle gasoline engines .45 to .37 SFC in lb/(hp·h

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115 000 btu gallon / 6 = 19,166.7 btu per lb of fuel burn.
So ~.5 lb fuel burn per min per hp = 14,000 to 15,000 btu a min heating.
Implies 50 hp burns 750 000 btu/min, 100 hp 1,500,000, 150 hp 2,250,000 [millions!] btu per minute. 200 hp 3,000,000 but/min. ugh.

Guessimating 33% heat converted to motive force/torque, 33% blown out the tail pipe and 33% radiated by engine structure to air. Implies Ms Peel may need to shed 830,000 btu/min vs 250,000 of regular Combat. That's like 66% or 2/3'rds more heat to radiate than a hot factory Combat head.

Hottest air cooled heads I've read of that survived awhile is 425' F, Exht gas well over 1400' F.

I don't think a few more holes or extra fin or two is up to the task.
I'll have water to spare, but how and where best to apply it? Would thermal shock or distortion be and issue?

Can anyone post the Norton factory illustration of the cooling flow paths ?

With water mist might be able to do similar btu figuring for NOS, then Alcohol, then nitromethane,

then drealy beloved, we are gathered here today....

Are you running an iron cylinder [or sleeve] block?
Thermal rejection limits are a primary reason why racing 2Ts stopped using iron bores & went to liquid cooling at around 200hp/ltr specific output [now at 440hp/ltr], with sophisticated designs running discreet coolant loops for head & crankcases [2T cases heat up from compressing air for transfer jet-flow].

Oh ugh JAW's, I've lost many hours sleep configuring tube wrap to run coolant through, but finally put it out of mind. Ms Peel has Maney all alloy engine with extra mass for lower heat sink, combustion exposed surfaces all ceramic insulated and whole engine Black Body Emission coated semi gloss black. I've restricted the polished cover areas to TS cover and outer blower cover as polished Al is one of the best IR mirrors - ugh- on both sides. All cryogenic tempered thermal tolerant a bit more even the Al as it compresses so hard that cold its like internal shot peening and assists heat conduction better. But all of this is just for daily use in public, not nearly enough for trying to embarrass 200 hp bikes to some ungodly speed, which I expect to get out run after 160 of so, if they can accelerate long enough to make up what they lost in the leaning sections. Then piston oil jets kick in and external sprayers. Power is sure fun and helps bikes compete but its only half the equation, must be able to use-hook it up to really matter. Then we get into tire heat issues. Maybe spray their side walls too? Can't get 160 rated tires in Norton sizes so have shave em to go up a speed heat rating. I run race only tires on my old modern and they are rather thin to begin with.

Very cool work there Hobot, this may be of interest .

From 'Flight' magazine Nov`45, Napier Sabre VII article;
Discussion of water/methanol injection-[methanol is there as anti-freeze for "heights up to 40,000ft"]- "In the Mk. VII the percentage of water/methanol to fuel is of the order of 35% in M.S.[moderate supercharge] gear & 70% in F.S. gear, & it is, of course necessary to arrange proportionate stricture of the fuel passed by the fuel injector if over-rich mixtures are to be avoided."
Consumptions make for interesting reading.. "Fuel Max. take off [3,000hp @ 3,850rpm] 235 gallons/hr. Water/methanol at max take off power 65 gal/hr."
"It should be noted that at maximum combat conditions the Sabre VII produces no less than 3,055 b.h.p. which is equivalent to an amazing 83 b.h.p./ltr, a figure hitherto unapproached by any other aircraft piston engine in production...this standard of development applies also to the specfic weight, which has gone down tio the very low value of 0.83lb/b.h.p."

Oh yes indeed juicy stuff to show me JAW's and brings up an issue I think I can just fudge past, reducing the fuel supply as the water supply increases. RBRacing is a good site for water injection calculations and I called em too, to come to decide on first water ratio to spray in as 15% of fuel mass to approach 116 octane on 91 no lead no alcohol petrol. The 10% boozed gas would just be a bit more anti-detonation fluid to Peel. On boosted application as boost builds generally more fuel enrichment is provided to help stifle detonation. I think I can just toss in water to replace the fuel enrichment. I don't think I'll need water to come on until over 5-6 PSI boost, as Peel is made to be anti-detonation top to bottom and should at least equal that aircraft engine in power to wt to displacement ratio w/o need of water. Alas Peel must about double that example ratio to do what I want her too. The methanol has its own benefits beside as ant-freeze, its energy of vaporization refrigeration plus its a fuel too. Its very common for tubro guys to run bluish 50/50 windshield washer fluid in their sprayers.

I've another un- responded to post here with online engine calculators of various kinds, max port velocity, boost to CR changes and octane vs timing adv safety. Conjecture of those handling Peel's stuff is solid 120 hp at tire, but when I plug in 8000 rpm with the Drouin flow curve the figure come back like double that aircraft to point i can't sleep so only did it once and can't bring myself to print the numbers. Peel may have as good as it gets rpm tolerant crank as besides lightened about 5 lbs its also 1/2" smaller OD. Old crank did not survive the 11,000+ stuck throttle event but the spiffed up head/valve train did just fine, if not counting destroying the cam tensioner and oil pump snout.

Change of fuel to alcohol or nitro plus NOS impies just plain out of sight melt down level I might try when too old to ride any more, but one last time for world to remember...a color me gone Commando. I've got 50% hydrogen peroxide I could use instead of water then add a good dose of methanol for home brew oxygenated refrigerant fuel mix that could be more explosive than Nitrous and gasoline.

Realize though that the extra power is not what excites me on Peel the most, No Sir Ree Bob, its her ability to put down power to tire spin level leaned where everyone else and their sisters are hardest on brake, pashaw, bring on the 1000 hp 4wd rally cars and let have us a good ole time up and down Pikes Peak, oh yeah this don't do that downhill but its Peels daily breath commuting fun. I've also done calculation of torque per mass of the 200 hp GP bikes, hehe the poor things...

& dont forget the old T.E.L., you can still get lead octane boost ['Kemco octane supreme 130 -for off high-way use'].
The former G.P. [500 2Ts] 200+hp were artificially constrained by A, going lead free [softened power output] & B, being weighted up to 130kg min. Also bearing in mind that the current 1ltr 4Ts have to rev past 18,000rpm to make ~240hp, vs 13,500 for a 125cc/55hp 2T cylinder or multiple thereof.

Alternatively, convert to E85 gas [NASCAR now runs this?], but you`d have to put an 'interstate' tank on `er to get anywhere range-wise.

Ms Peel is designed to run on 87 octane and creek water to fit what available here yet still have enough performance to spank my intended bait fish to at least 160. What I most want to play games with are 1000 hp 4wd drive rally cars in their element. If conditions didn't allow them over 90 mph Peel 750 power handling would be enough. Cable straps to hold head/cylinder to cases may help dispel a bit more head heat : 0

Or a custom sand-cast Bronze alloy max heat rejection cylinder head, like the works Rudge?

Ugh, unexpected expenses and what not have delayed Peel at least 3 yrs now so will have to make do with Norton Alloy head. It has cross my mind lately about adapting a fullauto head to Peel. MIght help out after i get a side car rigged up.

From "Engine performance curves" - Factory data for H2, as cited in tech text book,
"The 2nd scale on the right is fuel consumption in grams per horsepower-hour.Note that maximum fuel economy [300gm/hp/hr] occurs just above the power peak. Elsewhere in this book, we show the maximum economy point as being below the power peak, which is true for engines in general, but not necessarily for every engine. 2Ts lose fresh mixture out the exhaust port, which accounts for the generally poorer fuel economy of 2Ts. When the exhaust system is resonant, one effect is to 'ram' some of this mixture back into the cylinder just before the exhaust closes, making the engine more efficient at that rpm."

It takes me a while to wind down to sleep, especially as that a prime time to think through Ms Peels issues, like when in jail fighting with corrupt judge on speeding ticket, realized Peel spends a good bit of time with stem lower than tail, YIKES, had to add a stem oil drain besides rear end drain. Anyway, every hot rod mod helps boosted applications too but most gains are gotten on exhaust side of head so I pay attention to what's known about exhausts getting the heat out. Btw my P!! ate H2's with just one down shift from top all the while listening to their screaming peddling up gears fading behind... I got in lots of fights early on, I finished, but never threw 1st punch, same with those stinking smoke bombs, they always started it...

So how much heat must be rid of via engine metal surface to air for say 140 hp? Oil can't do much more than carry heat out of thin shear spaces so about only reason for oil coolers are to protect the oil not the engine as Harley found out.

What gas does most the heat work?

The idea is to match hottest to coldest with maximum efficiency, this being crucial for piston engines in high speed airframes, & the air-cooled vs liquid cooled issue concerning both internal [within engine] & external [over engine & mounting], liquid winning when they could match low frontal area with jet duct radiator [net +ve thrust instead of drag penalty] plus the ability of water [excellent specific heat transfer] to be directed to internal engine hot spots. Further, over-cooling [during dives] & general engine management busy-ness meant aircooled mills were better for steady state flying monitored by a dedicated engineer.
Suzuki put significant effort into the 1st gen GSX-Rs when they transitioned from rolling element [2T] style cranks to high pressure/heat plain bearing type while trying to stay with oil-cooling using internal air/oil heat transfer schemes, but eventually had to admit defeat.
So in principle,the idea is to apply the coldest available flow to the hottest spots, except when it compromises o/all function [like having hot air from exhaust area of head then directed to inlet for aspiration].

So in principle,the idea is to apply the coldest available flow to the hottest spots, except when it compromises o/all function [like having hot air from exhaust area of head then directed to inlet for aspiration].

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Entertaining mental ski scapes to fly into. We have seen the hottest spot via thermal image posted, showed lower outer front head surrounding the exhaust but not so much between them. Some had added a 4th fin above with a side posts across em all to tie together and add more surface or turbulence. This seems most the hot air source that flows back to slap together on the carbs and air box area. Would be difficult to duck cold air to carbs location w/o snorkles. i'd saved a sheet metal duct i'd pondered mounting so scoop was under bike then directed upward, but grit and water and limbs allow it real life, but maybe for a special event. I'm considering side panel ducts-diverters to scoop more air past above hottest spot and would also help direct water spray for best effect.

I designed a blade like stream liner the pilot laid on his side, to find illegal for legal classes, but offered the best chance to duct all air and heat and water steam it for some thrust like the famous P51's under scoop-jet radiator. Just can't make too much power in air cooled to fit a cycle or aircraft w/o some hot spots vs cold spots to distort or thermal shock damage. The air cooled that could still needed water spray to up the conductive flow.

Hottest spot inside engine is the piston crown, more mass helps that but hinders performance. Early cast iron or steel piston had a center support on the wrist pin or sagged to failure. Some run oil ways inside pistons but modern hot rods jet oil up under, lots of it, like more than rest of engine needs, like most a liter a minute for ordinary hot rods to a few gallons a minute on dragsters, per piston. Research found minimal .6 L/m on our size unboosted pistons to get 100'F cooling. I'm be spending a few $100 to see if I can spray enough to matter for longer WOT runs or Peel. Its takes some good PSI to jet strong and fast enough not to be scattered by WOT windage. Jets can only hit piston on its decent, piston out races the jet on compression. Should not hit bores or over oils to burn-smoke. Too hot a piston also flashes oil to explosive vapors. Rather difficult to place em in a Norton twin too.

Lost propane so digging with sun radiance behind Mt now, chow.

Enjoy the chow, smoky chillie bbq pork spare ribs, mmmmmm.
Ol` P.Williams put some thought into a semi ram/cold airduct/carb air-box on the F 750 JPNs.
From tnat K.Cameron article re pistons;
" Success came when silicon was added to raise hot-strength. More recently, theinternal shape of pistons has evolved to extract heat faster.Dome thicknesses have been increased to speed heatflow to the walls.Where pistons once had internal ribbing, now smooth, flowing shapes prevail, for it has been shown that such organic contours better resist thermal stresses. The closer the piston ring can be placed to the top edge of the crown, the shorter the heat path & the smaller the volume of compressed charge that goes unburned in ring land crevices."
"The use of taper-sided 'keystone' Napier rings makes use of piston rocking to open & rinse groove spaces so that carbonising oil is regularly flushed out, but even so there is the problem of rings welding themselves to the aluminium piston material."
By eliminating iron liners, "A porous-chromium plating worked better, enabling air-cooled engines eventually to cool successfully at almost 7hp/sq.in. of piston area."