I understand that you like to go fast, and believe me, I explored also all ROP/LOP with temps etc. But the best answer to your question is: 70% power ROP = 70% power LOP, or in other words, when you are running your engine at 70% power it doesn't matter if you are running LOP or ROP !
70% power of 350hp = 245hp and if you do this running LOP or ROP it stays the same hp and therefore (in theory) your plane should fly the same speed (this I gathered at the last Lancair meeting from Tim Roehl, GAMI over lunch, really good stuff)
So....now the question stays, how much fuel flow do I need to get 70%hp from a 350hp engine, because that is what is moving your plane forward. (you can google the numbers but if I remember correctly ~18.5gph/2500rpm/32map but don't take my word for it, you just have to make sure you are at least 70 degrees LOP to run it that high, at lower MAP you can go even back to 25 degrees LOP)
Just keep in mind that running your engine at 70%hp is really the same LOP or ROP (now I know that perhaps your engine monitor says that you are at 70% but they also have their error margin, best thing to do is to calculate it through).
I hope this helps.....it did with me :)~ And who doesn't want to save money if the plane is flying the same speed LOP :)~
-- Ronald (110hours LNC4, 360hours Velocity TXL5, 1100hours Cirrus sr22 and some....)
ps I also asked Tim using TIT as tool and he confirmed that TIT is the average temp from your cylinders, but important here is that the GAMI spread should be very small (like < 0.5 gph) otherwise you could run into troubles without knowing this.
Dear subscribers,
When I run the engine lean of peak with a turbo temp around 1650 degree (75 LOP) I get really nice results in regards to head temp and IAS.
Studying the articles I understand that coming from the lean side first the TIT peaks and then head temps will peak later (means richer).
In case I really want to go fast sometime and don’t care about fuel consumption:
Can anyone give me a temp spread that I need to stay on the rich side from the peak TIT in order to be on the declining rich side of the head temp line and be safe?
Or is there another procedure to run ROP and have nice cool head temps. The fuel flow settings in the Continental for ROP operation make my head temps slowly creep above 400.
Thanks for your help
Ralf