Why am I going to pursue a pointless argument. The engine sees density, that is a basic fact.

You are going to claim you are correct despite the fact every other word in your argument is "temperature". Really?? :confused:

It is retarded.

Again, call Lycoming.....

Their customer service will answer your questions and you can argue with them and the FAA.

I don't, I face much the same trouble, but if you are a Physicist then perhaps you have better access to stuff from the scientific community, I dare say the British equvalents are available...just not so much on t'interweb.

Great point. But in the case of changing the fuel of an engine without modifying the design, the geo of the cylinder is fixed. Tht's why I am talking about T=f(octane grade) that is becoming the prime factor for the E you can output from the fuel (I might have the formula somewhere... In Canada, damn !).

My answer was to this :

If you change the fuel, the minimum you wld need is to modify the compression volume and material of the pistons/cylinders that you have an equivalent heat flux. Today, tuner can play with the injection para to artificially reset the volume or modify the air compression ratio playing with the boost ratio (carburated and injected) .

But this imply modifying extensively the engine. Especially if your daily hobby is a long and lonely flight in a single engine plane above the sea!

You need to understand the difference between detonation and deflagration.

http://en.wikipedia.org/wiki/Detonation

http://en.wikipedia.org/wiki/Deflagration

Lower octane fuel detonates.

No one denies that engine power depends on density on the manifolds, however, the argument was if the FTH depends on the density altitude or the pressure altitude in the case of the Merlin. As pointed out earlier, the supercharger of the Merlin keeps constant pressure up to the FTH regardless the density of the air (indicated by temperature), so it's clear that the FTH depends on pressure altitude, just like in the case of the radial engines with similar superchargers in the USAF handbook.

I end this discussion here, you just keep flossing a dead horse...

http://www.youtube.com/watch?v=Lb_IbFBdKw0

I don't see where I said the contrary but thx for the refresh. Pls explains what you mean instead of this mystic answer. I am not here to show off any knowledge but because I like others to understand better what this sim is emulating.

Again my reply was about the assumption form D. that octane grade had no link with the E that you can output. Damn do we really read each others ? Or is nailing and plinking becoming a sport here ? Because if you still don't know we have the ATAG server to that ;)

No. You are wrong.

If your engine was designed to run on a particular octane, at a particular compression ratio, and you put fuel in that has a HIGHER octane than before, the minimum that you need to do is nothing. The octane number is just a measurement of it's anti-knock performance. Octane number does not mean the fuel burns hotter, or has more energy in it, or has a "greater heat flux". You don't need to modify the engine if you want to put higher octane fuel in it.

On the other hand, if you want to run at a higher compression ratio, then you are required to increase the octane rating of your fuel.

CoD Hurricane Mk1 87 versus 100 octane
 

Results of my comparision demonstrate a marginal increase in performance of the 100 octane over the 87 octane Mk 1 Hurricane when using the boost cut out. There does not appear to be any increase of performance other than slight improved acceleration for the 87 octane when the boost cut out is pulled. What is demonstrated is that the 100 octane Mk1 is very prone to failure soon after employing the boost cutout. Works best at low altitude, but you have only 1 minute to engine destruction. At 20,000, the 100 octane will hold a steady at 210 mph +2.5 beyond 6 minutes whereas the 87 octane at +3 210 mph blows up after two minutes. Otherwise, you can run the 87 octane at +5.5 lbs all day at 240 mph. So my assessment is that the 87 octane is a better option for combat operations (e.g. very slight trade off in performance, versus substantial improvement in reliability)

Mk1 Hurricane Comparison between 87 and 100 Octane Rotol

100 Octane
87 Octane
Wind: 0 mph/0 % deflection
Boost Start 0 psi
Weight 3177 lbs
Fuel 100%
Start Speed 180 mph
Rad 100% Open
X engine failure

2,700 RPM SPEED & ACCELERATION
Altitude 1 min 2 min 3 min 4 min 5 min 6 min (BOOST)
5000 ft 240 mph 260 mph 260 mph X Goveror failure X +8
5000 ft 210 mph 230 mph 230 mph 240 mph 240 mph 240 mph +6.2

10000 ft 240 mph X Gasket failure X X X +8
10000 ft 220 mph 240 mph 240 mph 240 mph 240 mph 240 mph +6.1

15000 ft 220 mph 240 mph 240 mph 240 mph 240 mph 240 mph +7.2
15000 ft 230 mph 230 mph 240 mph 240 mph 240 mph 240 mph +6.1

20000 ft 190 mph 200 mph 210 mph 210 mph 210 mph 210 mph +1.5
20000 ft 200 mph 210 mph 210 mph 210 mph 210 mph 210 mph +3

3,000 RPM SPEED & ACCELERATION
Altitude 1 min 2 min 3 min 4 min 5 min 6 min (BOOST)
5000 ft 260 mph X Gasket failure X X X +8
5000 ft 220 mph 240 mph 240 mph 240 mph 240 mph 240 mph +5.5

10000 ft 240 mph X Gasket failure X X X +8
10000 ft 220 mph 240 mph 240 mph 240 mph 240 mph 240 mph +5.5

15000 ft 220 mph 240 mph 240 mph 240 mph 240 mph 240 mph +8
15000 ft 230 mph 240 mph 240 mph 240 mph 240 mph 240 mph +5.5
no BCO 220 mph 230 mph 240 mph 240 mph 240 mph 240 mph +5.5

20000 ft 190 mph 200 mph 210 mph 210 mph 210 mph 210 mph +2.5
20000 ft 200 mph 210 mph X Burnt intake X X +3

All engine failures were confirmed with a second test
All tests conducted with Boost Cut Out pulled

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Ok next time you take a Diesel, I suggest yu might try to put some 95 or 98 gasoline while I'll try myself to put diesel in a gasoline car. We will see who has the biggest bill.

First of all there was no argument. You are the sole voice of discontent. The engine sees density.

FTH depends on density altitude. Only in an engine equipped with a density controller will it reflect just pressure altitude. AFAIK, they did not have them in WWII.

http://quizlet.com/2496371/print/