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Last I heard Reno (In the traditional air racing guise) was no more, any news on an alternative venue?
Modern Racing Engines
- Thread starter Foo Fighter
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All -
It would not be surprising to see the Reno " Unlimiteds " supplanted by modern composite sport aircraft outfitted w/ monster HP per cubic inch; along with multiple-blade computer-designed propellers ( similar to the type used on C-130J, E2C; C-2A ).
This would silence purist complaints that comparatively rare WWII and other former MIL prop-driven aircraft ( that gave way to jets ) were being bastardized in the name of air racing.
It might also make race aircraft/team costs more palatable, and that could lead to a commensurate reduction in the expected " purse " for winners. This latter point could
go a long way towards coaxing the teams / races back into being.
With regards,
357Mag
It would not be surprising to see the Reno " Unlimiteds " supplanted by modern composite sport aircraft outfitted w/ monster HP per cubic inch; along with multiple-blade computer-designed propellers ( similar to the type used on C-130J, E2C; C-2A ).
This would silence purist complaints that comparatively rare WWII and other former MIL prop-driven aircraft ( that gave way to jets ) were being bastardized in the name of air racing.
It might also make race aircraft/team costs more palatable, and that could lead to a commensurate reduction in the expected " purse " for winners. This latter point could
go a long way towards coaxing the teams / races back into being.
With regards,
357Mag
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Last I know the announcement had been made of a short list replacement venue but, the winner was supposed to be announced in April this year.
Perhaps they will have to start racing over water again instead.
Perhaps they will have to start racing over water again instead.
I think its usually underestimated:
A) How much work it is to make a very sucessful automotive/motorsport engine into something that actually works properly
in an aeroplane.
B) How much indescribably complex and intense efforts went into making the original engines work properly.
The failed Rutan pond-racer plane makes this very evident.
If it were me I wouldn't let anything with sleeves or 2-strokes near a new racing plane, and unless you`ve got
an entire engine company at your disposal and many, many tens of millions of dollars floating about I would
not try to make a new Reno engine.
The best practical bet is to just do what everyone has been doing and just do it a bit better, and a bit
more comprehensively, which is to take a very late model Merlin or possibly Griffon and redo
a few very specific areas. Maybe make a new bespoke pair of cylinder heads and cams,
new pistons, rods and maybe crank bearings and keep pushing the boost and rpm up.
Of course you can do something better these days, but the cost and development time to iron
the bugs out are so astronomic that I just don't think its realistically ever going to happen.
A) How much work it is to make a very sucessful automotive/motorsport engine into something that actually works properly
in an aeroplane.
B) How much indescribably complex and intense efforts went into making the original engines work properly.
The failed Rutan pond-racer plane makes this very evident.
If it were me I wouldn't let anything with sleeves or 2-strokes near a new racing plane, and unless you`ve got
an entire engine company at your disposal and many, many tens of millions of dollars floating about I would
not try to make a new Reno engine.
The best practical bet is to just do what everyone has been doing and just do it a bit better, and a bit
more comprehensively, which is to take a very late model Merlin or possibly Griffon and redo
a few very specific areas. Maybe make a new bespoke pair of cylinder heads and cams,
new pistons, rods and maybe crank bearings and keep pushing the boost and rpm up.
Of course you can do something better these days, but the cost and development time to iron
the bugs out are so astronomic that I just don't think its realistically ever going to happen.
I totally agree, a classic v12 aero engine with a new head featuring direct injection, central spar plugs and modern ports would be a reasonable aporoach. An alternative could be a new design combined with well poven components based on e.g. the Chrysler Hemi.
Nik
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Tangential, I remember an issue at work where a specific problem would recur.
For reasons, the tried and tested solution was to quarantine the product until the deep-drawn aluminium can's surface equilibrated with the contents. Usually took the standard four weeks allowed, which covered ~85% of production. Rest could take six, eight even twelve weeks, via a long, lean tail.
IIRC, it always got there in the end.
Eventually.....
About every five years, some-one would come along, try to shorten the default 4-week quarantine, perhaps resolve the 'retest monthly' wait.
Hey, how hard could it be ??
Sad to say, I did not endear myself to latest whizz-kid by asking what they hoped to do different this time.
IIRC, the previous investigation. about 5~~7 years prior,, of which he was unaware, glumly reckoned they needed an ion micro-probe, x-ray activation analysis plus a raft of similar techniques to nail down the conjectures, quantitatively study how the cans' surface oxide layer and sub-surface metal interacted to progressively 'getter' the trace of moisture causing the problem.
One classic marker of an increasingly toxic corporate culture is when it becomes worse to be right than wrong...
But I knew that...
For reasons, the tried and tested solution was to quarantine the product until the deep-drawn aluminium can's surface equilibrated with the contents. Usually took the standard four weeks allowed, which covered ~85% of production. Rest could take six, eight even twelve weeks, via a long, lean tail.
IIRC, it always got there in the end.
Eventually.....
About every five years, some-one would come along, try to shorten the default 4-week quarantine, perhaps resolve the 'retest monthly' wait.
Hey, how hard could it be ??
Sad to say, I did not endear myself to latest whizz-kid by asking what they hoped to do different this time.
IIRC, the previous investigation. about 5~~7 years prior,, of which he was unaware, glumly reckoned they needed an ion micro-probe, x-ray activation analysis plus a raft of similar techniques to nail down the conjectures, quantitatively study how the cans' surface oxide layer and sub-surface metal interacted to progressively 'getter' the trace of moisture causing the problem.
One classic marker of an increasingly toxic corporate culture is when it becomes worse to be right than wrong...
But I knew that...
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OK, what would a 'reasonably' powerful engine and airframe combination look like? Is it not possible to come up with a sensible combination that would be entertaining while remaining affordable (Reasonably)?
It must be possible, they have done it before.
It must be possible, they have done it before.
You need to keep the frontal area small, so 90 deg bank angle is not ideal I would prefer 60. Long intake runners are not usefull for turbocharged engines, the turbo can fill the cylinders more efficient. Long exhaust runners are difficult for packaging and heating up the surrounding. I would prefer 4 small turbos on a V12, they could provide enough boost at the given altitude. Groups of three even firing cylinders are ideal for turbos and enable less residual gases and higher knocking resistance than a common turbo for 12.
Edit: dry sump is not really required for these type of races, because the g-forces are allways directed in almost constant direction downwards (to the airframe)
The Bugatti layout is way to complex
Edit: dry sump is not really required for these type of races, because the g-forces are allways directed in almost constant direction downwards (to the airframe)
The Bugatti layout is way to complex
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I know the guy who designed the 296 engine and I know that a high power V-6 with a 120 deg bank angle is quite tricky because of the main bearing loads. A 60 deg design would be lighter, less design effort and have a smaller frontal area. The advantage of the 120 deg layout is the lower CG wich doesnt't apply here. A false boxer (180 deg V-engine) could still be lighter than a 60 deg V 12 but oil splashing would cause a lot of losses and it would be about as wide as the 120 deg angle.
I have no expieriences with ethanol, but I guess with high boost pressures and small CAC it could work with direct injection.
I have no expieriences with ethanol, but I guess with high boost pressures and small CAC it could work with direct injection.
And there might be another way to get to a similar end.
it might be less work to build a "better" (2 stage 'integral'??) supercharger for a late series Allison to get to same power level.
By the time you build new heads, cams, rods, and etc. (plus I seem to recall that a Merlin needs some serious crankcase stiffening for high power and high propeller thrust / gyroscopic loads) how much 'Merlin' is left??
With any WW2 V-12 base engine a big part of the job would be designing and building a 0.33:1 (or so) propeller speed reduction gear to allow higher crank rpm while still turning the prop at a suitable rpm.
In a V6 for an even firing order you will want a 120 degree angle or you need split journals. The wide V can be used for packing twin turbos inside the V (hot V).
It would be interesting to have a look at the supersonic propeller research by NACA of the early 1950s which showed quite promising results for high speed propeller rpms and flight speeds beyond the normal limits. The noise should not be a problem for racing.
I'm aware of that, still every V6 has its drawbacks. The 120 deg is heavy and has free mass moments of 1th and second order.
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A hot-V could work with90 deg (has been done by BMW, Ford, Cadillac) but than the engine height will be increased. The exhaust piping is still quite long compared to outside turbos, because you dont want to expell the exhaus gases right on the canopy.
In a Di engine, the evaporation heat adsorbed during intake and compression, thus making them more knock resistant. It could be, that wall wetting will be a problem with Ethanol/Methanol.
There are companies making new engines for classic cars (eg the Alfa Romeo 8C 2300). For a production run of a few dozen, you're talking about $200k.
3D printing isn't viable yet for the major components (block, crankshaft, pistons etc), you need to cast and machine them.
3d printing of the crank case and cylinderheads can be done. 200 k is quite low, barly covering the production cost
Today's planes w/ high shaft horsepower turbines show widescale use of higher blade count propellers. Also seen, are swept ( "scimitar " ) blade shapes.
Amongst business turbo props, blade counts above 7 have shown useful benefits during flight testing.
Higher number of propeller blades can help to lower prop disc diameter; which should help w/ disc " drag ".
At some point... it would probably be argued that a really higher blade count constitutes an. " open fan " design. For an FAI speed record attempt aircraft, they should be contacted prior to commiting funds to a customer prop; as a practical matter. I have read that the 11 - 13 blade count props that have been flown on turbine powered planes, makes them sound similar to jets.
In the age of digital design, possible improvements in blade profiling to provide prop efficiency above WWII-era levels is a near certainty.
The Merlin, R- 2800, R-3350; and R-4360 have all been used to push " warbird "- based
" Unlimiteds" past 500mph. I am not sure whether the Skyraider prop on " Conquest1 "
had been re-profiled ?
With regards,
357Mag
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P-51 Carbon Fiber Mustang | Aircraft Spruce
P-51 Carbon Fiber Mustang The P-51 is a full size Carbon Fiber Mustang manufactured by Cameron and Son’s Aircraft. This aircraft is available with a 1450 hp turbine, or can be fitted with a Rolls Merlin. It is capable of speeds in the mid 4
Cameron Aircraft | Coeur d'Alene
Cameron Aircraft full scale composite P-51 airframes and unlimited hydroplane hulls. Resin infusion expertise. Vacuum infused resin composite construction of manned experimental and Autonomous aircraft. Composite Cozy Drone project.
www.cameronaircraft.com
Fair start point?
@Scott Kenny I'm not into that "psi thing", anyway port fuel injection might be a better option for alcohol, mybe with a bit of central injection before the compressor.
@Scott Kenny I'm not into that "psi thing", anyway port fuel injection might be a better option for alcohol, mybe with a bit of central injection before the compressor to lower the compressor work and temperature rise.
Whatever the airframe, perhaps drag reducing " riblets " could be added to minimize drag.P-51 Carbon Fiber Mustang | Aircraft Spruce
P-51 Carbon Fiber Mustang The P-51 is a full size Carbon Fiber Mustang manufactured by Cameron and Son’s Aircraft. This aircraft is available with a 1450 hp turbine, or can be fitted with a Rolls Merlin. It is capable of speeds in the mid 4www.aircraftspruce.com
Cameron Aircraft | Coeur d'Alene
Cameron Aircraft full scale composite P-51 airframes and unlimited hydroplane hulls. Resin infusion expertise. Vacuum infused resin composite construction of manned experimental and Autonomous aircraft. Composite Cozy Drone project.
Fair start point?
For an all-new composite aircraft, riblets might either be machined into skins of adequate thickness, or.....perhaps be formed and cured as integral to the skin(s) ?
As aside:.
The Macchi-Castoldi. M.C.-72 had radiators that appeared to be ( based on a 1-72 scale model I saw ) flush with the fuselage and float' outer mold lines.
If they did protrude out into the windstream, it would appear that they didn't give an excessive drag penalty. Thinking outloud... for a liquid-cooled engine application,
might it be possible to meld the riblets idea w/ radiator coolant channels/ tubes in a custom made unit(s) ? Hmmm......
One of wonders what might have been possible, for a notional M.C.-72 with retractable gear, no wire bracing; and an improved prop arrangement ?
Forgot to mention in a previous post response....
A RR " Griffon " was another engine used to power a modified WWII-era warbird past 500mph.
With regards,
357Mag
With regards,
357Mag
The obvious solution would be an inverted V with the turbos in the valley (hot-V) and the exhaust pipe running below the fuselage for an exhaust behind the cockpit.
That way you could also turbo-compound to the prop shaft via a turbo-generator and an e-motor that will also act as a starter-motor (
Regarding the question with supersonic props, Reno are open air races meant to attract the public. It depends of the venue to generate a profit. If 80% of them become deaf the first year*, you might have some difficulties further on.
*but, hey, what a blast, as they say
(Edited)
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What would be the intended ultimate application for this imagined propeller-driven aircraft, whose engine is a turbo-prop, or turbo compound, or electric or electric/ hybrid; etc ?
In other words... if the postulated aircraft has an engine in it other than a " reciprocating" one ?
With regards,
357Mag
In other words... if the postulated aircraft has an engine in it other than a " reciprocating" one ?
With regards,
357Mag
I like the idea of the inverted V with inside turbos (maybe because I'm German), but lubrication will be more difficult. With the very high speed of those planes, turbocompounding seems unecessary. A variabe cross section exhaus nozzle (as intended for the Republic Rainbow) will provide equal trust with less effort and weight. Keep in mind, that even in this class, the budget is not unlimited.The obvious solution would be an inverted V with the turbos in the valley (hot-V) and the exhaust pipe running below the fuselage for an exhaust behind the cockpit.
That way you could also turbo-compound to the prop shaft via a turbo-generator and an e-motor that will also act as a starter-motor (don´t know if that has been ever attempted but the rotating mass of the prop might ease the starting process).
Regarding the question with supersonic props, Reno are open air races meant to attract the public. It depends of the venue to generate a profit. If 80% of them become deaf the first year*, you might have some difficulties further on.
*but, hey, what a blast, as they say
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Yes, for this racing application exhaust thrust is more useful for generating speed than turbocompounding.
Scott -
Yeh…. That’s what I thought was being intimated.
Barring some major change(s) in the purse or race organization, it is doubtful the
“ big iron “ will be back. Before things went South, there had been restrictions put in-place to suppress any wide scale participation of new-wave airframe designs.
If memory serves… they had made a point to keep allowed airframe & power plant restrictions open enough to not disclude the FM….and R-2800 powered Yak, but something like a suped-up Glasair would be out.
It is also unlikely the Big Iron could be coaxed back to go head-to-head with some new composite airframe whizz bang racers, even were the rules re-written… and the purse boosted.
What is more likely ( IMHO ) would be new rules detailing a new class of racers, that would basically use previous “ Unlimited “ racing speeds as the benchmark to be worked towards; and ultimately exceeded. It could ostensibly be the new “ unlimiteds “
but… not without adjusted class rules.
Some thought might be given to residual thrust produced by engine exhaust, or perhaps even radiator exhaust ( on a P-51 style set-up )… whether any amount would be considered excessive vis a vis a mandate for recip w/ prop as the “ thrust “ producing method?
With regards,
357Mag
Scott -
Howdy ,
I think the Bugatti 100 would be excluded under the current wt limit, as it weighs 3,086lb empty.
Even w/ a notional 200lb pilot, I doubt the plane would hold 1,200lb of fuel.
Change the rules, night whar ?
With regards,
357Mag
Regarding the question with supersonic props, Reno are open air races meant to attract the public. It depends of the venue to generate a profit. If 80% of them become deaf the first year*, you might have some difficulties further on.
*but, hey, what a blast, as they say
I think the proverbial noise generated by supersonic props is a little bit exaggerated. I know the often repeated stories about XF-84H, but I have not seen / heared a single original (sound-)document about it. I am sure it was loud but there are other planes where a part of the prop reaches supersonic speeds (at least during high speed flights when the combined vector of rotational and forward speed of the propeller leads to supersonic flow). And we talk about racing events, not business travel.
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Balance shafts could solve this (I know, additional weight, etc.).
The choise of LS engines seems logical, but we should not forgett, that the Pond racer failed because even the reliable Nissan race engines failed when running with max power for 15 min. This is something very different to any automotive application.
All -
Howdy !
How much HP & torque could be expected from the turbo’d LS ?
Lavelle’s Glasair that went 403mph used a TIO-540 twin turbo, stated to have 850hp output; with a capability to be pushed to 900hp.
Torque was rated @ 1,594 ft lb, estimated.
75” propeller, with 3 Scimitar shape swept blades
Race weight = 2,100 lb
IMHO -
A racer conforming to current “Unlimiteds”rules would need more than a hopped-up LS
With regards,
357Mag
Howdy !
How much HP & torque could be expected from the turbo’d LS ?
Lavelle’s Glasair that went 403mph used a TIO-540 twin turbo, stated to have 850hp output; with a capability to be pushed to 900hp.
Torque was rated @ 1,594 ft lb, estimated.
75” propeller, with 3 Scimitar shape swept blades
Race weight = 2,100 lb
IMHO -
A racer conforming to current “Unlimiteds”rules would need more than a hopped-up LS
With regards,
357Mag
Last Corvette ZR1 is twin Turbo powered with 1000+ Hp & 1200Nm in a reliable package (at least they say!)
You can certainly make something with a twin LS set modified for an overall conservative 3000hp,
The Grumman F-7 had only 30% more power for more than 3 time the dry mass of an unlimited and reached credible speed to win a race.
View: https://youtu.be/jDqkkB3DNLg?t=168
You can certainly make something with a twin LS set modified for an overall conservative 3000hp,
The Grumman F-7 had only 30% more power for more than 3 time the dry mass of an unlimited and reached credible speed to win a race.
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Last Corvette ZR1 is twin Turbo powered with 1000+ Hp & 1200Nm in a reliable package (at least they say!)
You can certainly make something with a twin LS set modified for an overall conservative 3000hp,
The Grumman F-7 had only 30% more power for more than 3 time the dry mass of an unlimited and reached credible speed to win a race.
View: https://youtu.be/jDqkkB3DNLg?t=168
Or just have a look at the 9 liter V8 twin turbo Mercury Racing engines which are designed to run at constant high power settings. These dry sump aluminum engines could serve as the basis for aircraft racing applications.
Dual Cal 1550/ 1350 | Sterndrives | Mercury Racing
Get maxmium torque and power with the Dual Cal 1550/1350 sterndrive engine. Switch between racing and pleasure for the optimal boating experience.
www.mercuryracing.com
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