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More power will always produce a better rate of climb and a higher top speed, with little gain in weight. The effect on rate of climb and top speed depends on the aircraft. A ww1 aircraft was light with a lot of drag, more power would affect rate of climb much more than top speed. "Compression ratio" applies more to early un supercharged engines, with a supercharger it is boost pressure increase that matters, the increase in octane value is just to allow that increase in boost without detonation.Hi
One or two commenters say that the higher octance fuel with higher compression ratio would produce more power and faster climb rate but not greater horizontal speed. If someone could explain that I would appreciate it.
thanks
Hi
One or two commenters say that the higher octance fuel with higher compression ratio would produce more power and faster climb rate but not greater horizontal speed. If someone could explain that I would appreciate it.
thanks
Hi
One or two commenters say that the higher octance fuel with higher compression ratio would produce more power and faster climb rate but not greater horizontal speed. If someone could explain that I would appreciate it.
thanks
No doubt, the operationals D9s were badly outperformed on the western front. But if we want to compare airframe to airframe, then we should consider reasonable production facilities for the D9 and availability of fuel.Basically, most (?) European fighters were point defense fighters , after all almost everything is pretty close. The most impressive feature of the P-51 was that it could fly 600 miles, engage these lighter defensive fighters with full combat fuel and with formidable effect and then fly 600 miles home. This is a general statement and general statements are often dangerous, most flight test are performed at combat weight which usually means full internal fuel, except the P-51 which has an internal extended range tank. So, to really compare airframe vs airframe to the Fw 190 D-9, the P-51 would have to be tested at 138 gallons of fuel instead the normal tested 180 gallons, or about 250 lbs lighter. So, yes added fuel affects performance but these test include that effect.
Hi Mike Williams,
Questions on post #22. I do not dispute the chart, but how is it possible thaht the rate of climb has a discontinuity in it? Shouldn't it be one, continuous curve?
Just curious. Cheers.
On the youtube video of P-51 vs FW 190 Greg has put up some comments addressing points made in this thread.
Put the comments on the youtube video in newest first. There are 2 under gregmcn11
Unfortunately, Greg didn't address the claims - that I find badly wrong - forwarded via your question to him:
- hi-oct fuel increasing speed at high altitudes vs. use of low-oct fuel at high altitudes
- remotely-installed S/C stage on P&W radials
- UK/Merlin being dependant on US-supplied 100 oct fuel before 1941, with Roosevelt breaking the US law in process
- Merlin was 'sucking tit' before the Americans gotten involved in Merlin development and production
- 2-stage S/C on Merlin was at least 'US derived', if not outright 'US-made'
He uses your site to justify his claims about 100 Octane but wont post here lol.Geez, that is bad...
Greg from Greg's Planes and Automobiles is right about more than he is given credit for.
1 High Octane fuel can improve the high altitude performance of an engine but it requires a mechanical change in the engine (increased compression ratio). Daimler Benz did this on several of its engines.
2 US Refineries did ship 100 octane fuel to the UK. It's true that the USAAF specification for 100 octane was different to the RAF specification for 100 octane. Both fuels shared the same lean rating but the RAF fuel specified a rich mixture Performance Number (% power increase) thusly 100/130. US refineries that shipped fuel to the UK adjusted their cuts to match the UK specification as much as possible. For a few months the fuel may have been 100/125 instead of 100/130. After that the US refineries had the equipment to meet the RAF specification most notably test engines that could measure a P/N performance number.
The UK was able to make its own 100/130 fuel by its own refineries and technology (mostly in the Caribbean) , most notably acid alkylation but its clear that the US was shipping vast amounts of this fuel as well.
I listened to this again, my, he does like the sound of his own voice doesn't he? At 46 minutes he argues that he flies all over the world and only the Chinese (but not all of China) use meters as a measure of altitude. Having worked in China and Russia and Japan and Mexico and many other countries in Europe and the middle east they have no concept of what a "foot" is, if required in a contract they will convert from their normal measurement which is meters to feet. Of the many howlers in his propaganda this is perhaps the most outrageous, why mention China and the Chinese and why imply they are somehow backward for not using feet as a measurement, the meter is the ISO standard measurement for length, why pretend otherwise?
He said a few Chinese in a few parts of China. All of China uses Metric or their traditional measures many of which are standardised to metric, as do the Russians. That is more people than North America and Europe combined. The reason they dont and wont use "feet" is because they have their own traditional measure Chi which means foot and is 13.12 inches because it is standardised on metric being exactly 1/3 of a meter 33 1/3 cm. Outside of aviation control measurements of the atmosphere are all standardised on metric ISO. The discussion is about superchargers, the people involved actually use pressure in their calculations which an altimeter converts to whatever the maker wants for the client. Only the wildly eccentric would defend using thousands of feet in one direction and miles, nautical miles mph and kts in the others.Unfortunately the aviation industry worldwide (almost) uses feet for altitude readings.
I have a really simple rule which really helps if you are publishing material on a historical channel, printed or video. If you do not have it written in a primary source archival document, don't say it; that gets you out of so much trouble.