Ralf,
Your LOP numbers look pretty good….including speed. That is assuming your IAS is correct. Line number 32 is a little too rich for my blood. TCM max cruise is about as abusive as its gets. I would never run my engine there. The problem I see is your take-off fuel rate is set too low. It should be around 41 gph at your take off RPM and MAP. At 38 inHg and 2700 rpm, it should be around 43 gph. I am pretty sure the low “full rich” fuel rate is what is causing your climb out CHT’s to climb above 380 degF. I had my electric fuel low boost switch fail and my CHT’s went up to 400 degF at 16000. I descended to 12000 and finished the trip home without low boost. Increase your take off fuel rate and you will be happy. “I think”.
Craig
Dear subscribers,
Thanks to everybody to help me understand the LOP operations. The Pelican articles helped a lot and Craig spend a lot of time writing everything down for me.
I determined my TIT (which was surprisingly low) and I took all the discussed power settings and ran them at 10000 and 18000. I waited several minutes on each setting to make sure that I have stable conditions.
In my table you can find the climb and all the power settings we discussed so far. May be you have some recommendations after looking at my data.
IAS and TAS I took from my steam gage – any corrections are welcome to correct my numbers.
In climb (full fuel – just me) I forgot to turn on the boost pump – this makes my CHT temps go up starting at 7000 ft. When I turn the boost pump on everything usually stays below 385F. Since I am burning so much fuel in climb I would be happy if you could recommend power settings for the climb.
At 10000 I tried the recommended TCM MAX Cruise power settings and it made my head temps slowly creep up. I stopped at 400F. And I even went richer than TCM recommended. The temp spread between TIT max and TIT at TCM max cruise was only 40F. It seems my engine does not like it – have you experienced anything similar? It seems I am on the down slope of the TIT curve but still around the peak of the CHT.
Unfortunately my IAS at 10000 were significantly lower that Jeff Liegner’s at 8000 in a previous posting L.
Some of the power settings gave me not a perfect smooth running engine – I probably should not call it rough.
I have the B version of the engine which is rated for 38 inHG. But it just does not want to go up all the way. I tried to adjust the rpm at the governor but it does not change much. The RPMs go up to 2700 on some days most of the time they stay at 2670 or so. I never saw 38 inHG so far – any comments?
Since the last max power test I put the gap seals on (4 tapes per control surface from wings and wheels) and I coated the plane with Kiss polymers. I think I see an improvement of 3 kts or so. How much the plenum (with all the sealing recommendations from Fred Moreno) helped I cannot tell because I don’t have real before / after data. Between the before / after rebuilt of the complete airplane the speed of the plane increased by 20 to 25 kts (but I had huge holes and gaps in/around the fuselage).
Static wicks: the outer one on the aileron vibrates a lot. The inner one seems almost still. I lost already the two outer ones because they unscrewed themselves. Do you use Loctide for yours or do I have an extraordinary problem going on. The ones on the elevator I can’t see but they are still there so I assume they are fine.
Thanks for your help
Ralf