TECNAM P2012 Rollout
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27/09- AVGAS vs MOGAS
run an IO540 on MOGAS and you will find they produce far far less power for the same amount of fuel.
run an IO540 on MOGAS and you will find they produce far far less power for the same amount of fuel.
I am really keen to know as the laws of physics I work with could be wrong.
And yes there are notable issues with various grades of mogas, but lets look at the power issue first.
run an IO540 on MOGAS and you will find they produce far far less power for the same amount of fuel
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I don't think the IE2 is actually certified to run on MOGAS, 'unleaded' yes, but they are not the same thing.
If you try and run an IO540 on MOGAS, yes it would probably run fine on a cold day, fully rich. There are probsbly plenty of people that have tried.
But if you want to run it consistently, on a hot day, at high power settings, leaned out.
it won't run fine.
You misunderstand the idea behind octane rating, high octane fuel is specifically to reduce detonation, that is it basically 'less flammable' or rather 'less explosive' but it happens
If you try and put MOGAS in an IO540 and run it at full power, it may produce the same power for a little bit before detonating, because of the lower octane rating and the high specific energy it will not run.
Go and ask continental or lycoming.
I should have said, 'in the real world, an IO540 won't produce the same power with the same amount of MOGAS as it would on AVGAS without detonating.
If you look at the KW/L or NM/L figures of a lycoming or conti and compare them to even a modest non turbo passenger car engine, you will find a lyc or conti produces less than half.
The only time a conti or lyc has an advantage is in power to weight ratio, this is only really because of how simple they are.
I'm not saying an auto engine is appropriate for an aircraft.
At the end of the day,
If you try and run an IO540 on MOGAS, yes it would probably run fine on a cold day, fully rich. There are probsbly plenty of people that have tried.
But if you want to run it consistently, on a hot day, at high power settings, leaned out.
it won't run fine.
You misunderstand the idea behind octane rating, high octane fuel is specifically to reduce detonation, that is it basically 'less flammable' or rather 'less explosive' but it happens
If you try and put MOGAS in an IO540 and run it at full power, it may produce the same power for a little bit before detonating, because of the lower octane rating and the high specific energy it will not run.
Go and ask continental or lycoming.
I should have said, 'in the real world, an IO540 won't produce the same power with the same amount of MOGAS as it would on AVGAS without detonating.
If you look at the KW/L or NM/L figures of a lycoming or conti and compare them to even a modest non turbo passenger car engine, you will find a lyc or conti produces less than half.
The only time a conti or lyc has an advantage is in power to weight ratio, this is only really because of how simple they are.
I'm not saying an auto engine is appropriate for an aircraft.
At the end of the day,
Supermouse3: If you look at the KW/L or NM/L figures of a lycoming or conti and compare them to even a modest non turbo passenger car engine, you will find a lyc or conti produces less than half.
Kw/L is partly tied to reliability. How many automobile engines will produce 100% rated power every time the car gets moving and then will run at 75% of their rated power for the whole of every trip.
Some aircraft engines are rated a 100% max continuous for the whole of their 2000 hour TBO life. Show me any automobile engine that will do that out of the box.
The Kw/l is also because of the low RPM a non geared aeromotive engine needs to run at to keep the prop tip speeds down. Successful geared aeromotive engines of more than 100 HP with less than 9 cylinders are pretty thin on the ground. Have a look around the see how much money has been spent (wasted) on developing automotive engine for aeromotive use.
Nm/L is also an invalid comparison. An automotive engine in an aircraft would have similar Nm/l as an aircraft engine.
The only correct comparison is to use BSFC figures.
Supermouse3: If you try and put MOGAS in an IO540 and run it at full power, it may produce the same power for a little bit before detonating, because of the lower octane rating and the high specific energy it will not run.
A few years ago there were plenty of O-320s being run on mogas on this side of the ditch with no adverse affects.
I cannot see why an O-540 or IO-540 would't run quite happily on mogas. In fact I suspect plenty of them have been run on mogas quite successfully.
Remember these are not high compression engines.
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Yes of course it would run, but only at full rich, not leaned.
AVGAS has fairly similar octane ratings to 98RON fully rich. Not leaned,
And I would say actually that any (aluminium) automotive engine would run perfectly happily for far more than 2000HR flat chat. Liquid cooling ensures they stay at the same temperature regardless of power output
Aluminium starts to fatigue at Temps above 350F, liquid cooling around the heads would prevent this, liquid cooling around the heads also lowers temps around the valves so they no longer require sodium filling and can run hotter allowing a more complete burn at stoichoimetric ratio. All without avgas. Or dual spark.
Liquid cooling also allows the use of higher tolerances, and better oils.
Ensuring less wear, and less oil bypass/ burning.
But no, automotive engines do not suit aircraft as everyone knows.
Automotive engines are designed to run on a very wide RPM band, obviously meaning they aren't efficient doing 5000-7000rpm even with variable valve timing.
Have you looked at the conditions the BSFC you are quoting was tested though? ( it changes with conditions)
The lyc and conti's are great engines, they've had a great run. But we are in 2016.
Materials have come along way since the 1950's, I know both lycoming and continental have improved the basic design with better materials like nikasil cylinder liners and sodium filled valves and better manufacturing processes. FADEC helps,but the IE2 still runs a distributor, which in cars was dropped in the 90's!
If we want to get GA back to the glory days manufacturers must get out of the past glory days.
A liquid cooled, flat 4,6 or 8, aluminium, turbocharged and inter cooled, with similar weight to the lyc's or conti's is certainly possible, and would easily produce more power.
lycoming and conti can't afford to,
An entire new engine can cost 100's of millions to design, test and produce.
Not to mention the cert cost.
The main reasons they haven't is not because the current crop are the best,
It's the cost, they can't afford to design end certify an engine that's a complete drop in replacement for old aircraft, at the same time as meeting the needs of modern aircraft.
AVGAS has fairly similar octane ratings to 98RON fully rich. Not leaned,
And I would say actually that any (aluminium) automotive engine would run perfectly happily for far more than 2000HR flat chat. Liquid cooling ensures they stay at the same temperature regardless of power output
Aluminium starts to fatigue at Temps above 350F, liquid cooling around the heads would prevent this, liquid cooling around the heads also lowers temps around the valves so they no longer require sodium filling and can run hotter allowing a more complete burn at stoichoimetric ratio. All without avgas. Or dual spark.
Liquid cooling also allows the use of higher tolerances, and better oils.
Ensuring less wear, and less oil bypass/ burning.
But no, automotive engines do not suit aircraft as everyone knows.
Automotive engines are designed to run on a very wide RPM band, obviously meaning they aren't efficient doing 5000-7000rpm even with variable valve timing.
Have you looked at the conditions the BSFC you are quoting was tested though? ( it changes with conditions)
The lyc and conti's are great engines, they've had a great run. But we are in 2016.
Materials have come along way since the 1950's, I know both lycoming and continental have improved the basic design with better materials like nikasil cylinder liners and sodium filled valves and better manufacturing processes. FADEC helps,but the IE2 still runs a distributor, which in cars was dropped in the 90's!
If we want to get GA back to the glory days manufacturers must get out of the past glory days.
A liquid cooled, flat 4,6 or 8, aluminium, turbocharged and inter cooled, with similar weight to the lyc's or conti's is certainly possible, and would easily produce more power.
lycoming and conti can't afford to,
An entire new engine can cost 100's of millions to design, test and produce.
Not to mention the cert cost.
The main reasons they haven't is not because the current crop are the best,
It's the cost, they can't afford to design end certify an engine that's a complete drop in replacement for old aircraft, at the same time as meeting the needs of modern aircraft.
Supermouse3: And I would say actually that any (aluminium) automotive engine would run perfectly happily for far more than 2000HR flat chat. Liquid cooling ensures they stay at the same temperature regardless of power output
As to the use of MOGAS, there's STC's to run MOGAS with no limitation on leaning. The main issue with using MOGAS is vapour lock.
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Ally is not restricted to supercars..
In actual fact I would be surprised if a supercar wouldn't make 2000H.
Cirrus SR22T's are 'approved' to run 94UL- at much higher fuel flows. With rich of peak ops only. ( full FADEC)
And no. I'm not a rich of peaker.
The issue is not just vapour lock, lead is also a lubricant.
In actual fact I would be surprised if a supercar wouldn't make 2000H.
Cirrus SR22T's are 'approved' to run 94UL- at much higher fuel flows. With rich of peak ops only. ( full FADEC)
And no. I'm not a rich of peaker.
The issue is not just vapour lock, lead is also a lubricant.
An engine builder friend of mine says a 7L V8, turbo charged could easily produce 400Hp for 2000+ hrs. He knows a thing or two as he makes endurance engines in the 2000 Hp range. Now we are talking bespoke blocks and internals, forged H beam rods, etc. Very expensive components. A it heavier than an aero engine......he guesses 10%. Forgings have advanced incredibly in recent years, as has the science of combustion chambers and fuel injection. Interestingly he also says rpm is a big factor. To produce the same Hp, going from 2700 rpm to 5000 rpm actually reduces the stresses on the components. So the V8 is under less stress at 5000 rpm. Cooling (temperature management) is the key to longevity of any reciprocating engine.
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Not bad looking aircraft, if said motors not ok (several to pick from at a bit less range) {tsio 540 seems to work}
Paxs like room or same amount of room + covered.
Cost???????????? on a 20 year plan, purchase cost and depreciation beats SIDS. Try depreciate Sids.
Paxs like room or same amount of room + covered.
Cost???????????? on a 20 year plan, purchase cost and depreciation beats SIDS. Try depreciate Sids.
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I think Cape Air will be well served by the new TECNAM P2012 Traveller.
My sister occasionally flies from BOS to MVY (Martha's Vineyard), and she said she would fly on the P2012 without hesitation.
Back to the Orenda OE600, remember the rated performance figures were achieved on 100LL gasoline. I don't know the grade of gasoline the current TRACE engine burns.
OE600:
- Performance: 600 hp @ 4,400 rpm takeoff (447 kW), 500 hp continuous (373 kW)
- Fuel Consumption: 0.44 lbs./hp/hr (100LL)
- TBO was established at 1800 hours.
(TRACE Engines have achieved a TBO of 2000 hours).
My sister occasionally flies from BOS to MVY (Martha's Vineyard), and she said she would fly on the P2012 without hesitation.
Back to the Orenda OE600, remember the rated performance figures were achieved on 100LL gasoline. I don't know the grade of gasoline the current TRACE engine burns.
OE600:
- Performance: 600 hp @ 4,400 rpm takeoff (447 kW), 500 hp continuous (373 kW)
- Fuel Consumption: 0.44 lbs./hp/hr (100LL)
- TBO was established at 1800 hours.
(TRACE Engines have achieved a TBO of 2000 hours).
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Supermouse,
There are a few differences in premium mogas and ordinary mogas so I guess you need to be specific. 100MON Avgas is typically around 102.5MON and our high octane pump mogas is 88-90. RVP is variable by season but a nominal 7.5 vs 15 PSI is significant.
You can run an IO540 (not TIO) successfully on premium unleaded provided spark timing is not advanced excessively, the oil temperature and inlet air temperature are not too high and at high power output the mixture is sufficiently LEAN enough or sufficiently Rich enough.
Important NOTE: Appropriately LOP mixtures are detonation free. This is contrary to popular myth, but it is fact none the less.
Even when detonation is occurring the HP remains fairly constant, however the pressure waves around the combustion chamber do attack the thermal boundary layer driving CHT's up quickly, which self promotes more detonation, and if the pressure spikes are severe enough they attack spark plug ceramics and ring lands etc. This has to be worked hard at to achieve I might add on Avgas, and is still not easy with PULP.
Switch to a turbocharged engine and the IAT is much higher, especially without intercoolers, and with mixtures in the 30-75dF ROP range detonation is quite likely.
Lastly TetraEthyl Lead is NOT a lubricant. At all. In the minute quantity present it could not do anything even if it was a super lube, besides it turns into a salt when burned and they make crappy lubricants.
Happy to discuss this in a sensible scientific manner but we must slay a few old wives tales along the way.
There are a few differences in premium mogas and ordinary mogas so I guess you need to be specific. 100MON Avgas is typically around 102.5MON and our high octane pump mogas is 88-90. RVP is variable by season but a nominal 7.5 vs 15 PSI is significant.
You can run an IO540 (not TIO) successfully on premium unleaded provided spark timing is not advanced excessively, the oil temperature and inlet air temperature are not too high and at high power output the mixture is sufficiently LEAN enough or sufficiently Rich enough.
Important NOTE: Appropriately LOP mixtures are detonation free. This is contrary to popular myth, but it is fact none the less.
Even when detonation is occurring the HP remains fairly constant, however the pressure waves around the combustion chamber do attack the thermal boundary layer driving CHT's up quickly, which self promotes more detonation, and if the pressure spikes are severe enough they attack spark plug ceramics and ring lands etc. This has to be worked hard at to achieve I might add on Avgas, and is still not easy with PULP.
Switch to a turbocharged engine and the IAT is much higher, especially without intercoolers, and with mixtures in the 30-75dF ROP range detonation is quite likely.
Lastly TetraEthyl Lead is NOT a lubricant. At all. In the minute quantity present it could not do anything even if it was a super lube, besides it turns into a salt when burned and they make crappy lubricants.
Happy to discuss this in a sensible scientific manner but we must slay a few old wives tales along the way.
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Yes and the way mogas and avgas is measured is different, kind of like saying jet-A and diesel are the same. Yes you can run a diesel on both, but they won't be the same.
At the end of the day, you can run a 540 on 98RON, but under very particular operating conditions, provided the state of tune is very accurate ( how many are) and if you can recognise detonation and prevent it.
Well aware of most of the old wives tails, maybe in the days of higher octane avgas lead served to reduce valve wear, but unsure if modern lyc's and conti's still suffer. So I stand corrected.
Also doesn't mean they are an acceptable engine for the future of GA, maybe keeping the current crop of aircraft operating, (which is I think what my original comment was about) STC's to allow them to run mogas would be cheaper (than developing an entire new fuel) via electronic engine control systems like FADEC but simpler, more in line with an '80's car engine.
At the end of the day, you can run a 540 on 98RON, but under very particular operating conditions, provided the state of tune is very accurate ( how many are) and if you can recognise detonation and prevent it.
Well aware of most of the old wives tails, maybe in the days of higher octane avgas lead served to reduce valve wear, but unsure if modern lyc's and conti's still suffer. So I stand corrected.
Also doesn't mean they are an acceptable engine for the future of GA, maybe keeping the current crop of aircraft operating, (which is I think what my original comment was about) STC's to allow them to run mogas would be cheaper (than developing an entire new fuel) via electronic engine control systems like FADEC but simpler, more in line with an '80's car engine.
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Supermouse
Avgas unlike Mogas is not tested on a RON (research octane number) engine, so you'll never see a RON rating quoted for Avgas. It would be however roughly 115 RON. The MON (motor octane number, different octane engine) of a 98 RON Mogas would be around 88 MON. So you can see that the anti detonation performance of the 2 fuels is vastly different. Avgas is made from higher octane blendstock to start with plus the addition of Tetra ethyl lead (TEL), an anti knock additive, produces the superior octane ratings. Avgas is also tested on a third type of engine, a boosted (supercharged) octane engine to give a rich rating performance number (PN) which is why Avgas is/ was quoted as Avgas 100/130 for example. (100 MON, 130 PN).
Trying operating an engine designed for Avgas on Mogas and it will destroy itself very rapidly.
I operated, installed, maintained, overhauled etc octane engines for 20 years so I guess I know what I'm on about..
Cheers
Octane
Avgas unlike Mogas is not tested on a RON (research octane number) engine, so you'll never see a RON rating quoted for Avgas. It would be however roughly 115 RON. The MON (motor octane number, different octane engine) of a 98 RON Mogas would be around 88 MON. So you can see that the anti detonation performance of the 2 fuels is vastly different. Avgas is made from higher octane blendstock to start with plus the addition of Tetra ethyl lead (TEL), an anti knock additive, produces the superior octane ratings. Avgas is also tested on a third type of engine, a boosted (supercharged) octane engine to give a rich rating performance number (PN) which is why Avgas is/ was quoted as Avgas 100/130 for example. (100 MON, 130 PN).
Trying operating an engine designed for Avgas on Mogas and it will destroy itself very rapidly.
I operated, installed, maintained, overhauled etc octane engines for 20 years so I guess I know what I'm on about..
Cheers
Octane
Supermouse3: STC's to allow them to run mogas would be cheaper
People are already doing successfully the things you say cannot be done or will be difficult to achieve.
I don't see Lycoming nor Continental avgas engines being knocked off their perch any time soon. A few have tried but none have succeeded. The fact of the matter is it's very hard to improve on the figures already being achieved with these "old dinosaurs". Certainly nowhere near enough gain to make it worth while.
The only option that has gained any traction has been the odd one or two diesel engines and their merits are very doubtful as a replacement option for an existing airframe.
Lead does not provide a lubricating function. Its mechanism of reducing valve wear is by preventing the micro welding of the seat/valve together when closed, and the resulting pitting in the surfaces when they are pulled apart (valve opening).