exM20K Posted February 16 Report Posted February 16 a friend is breaking in a 280hp acclaim for a third person. Like me, my friend has the 310 HP STC, while the subject plane does not. the CMI instructions for fuel system setup show 30-30.7 GPH at 33x2500. is that what you see in the climb? It sounds low to me, and I can’t find that power setting specified in the POH. TIA. -dan
dkkim73 Posted February 17 Report Posted February 17 Climb recently with all money knobs fwd was about 34" MAP and 34.5-35.2 gph. My flow sensor probably slightly overindicates (a few % perhaps). Also FF turned up a bit to get TIT 1350-1370F in the climb. But still, yes, those #s seem low. 1
Schllc Posted February 24 Report Posted February 24 If the turbo can run safely in the 1550 range while in cruise, why should the tit be so low in the climb? I have always shot for under 1500 on the tit in the climb, and cht's below 380. I am not even sure why its important to keep that low, i was just doing what i was told. can someone explain the reason for lower tit in the climb?
dkkim73 Posted February 24 Report Posted February 24 41 minutes ago, Schllc said: If the turbo can run safely in the 1550 range while in cruise, why should the tit be so low in the climb? I have always shot for under 1500 on the tit in the climb, and cht's below 380. I am not even sure why its important to keep that low, i was just doing what i was told. can someone explain the reason for lower tit in the climb? I think it's so that you're comfortably ROP in all cylinders with a good margin incl on CHTs. I was advised to boost fuel flow to achieve the TIT #s I mentioned. Paul @kortopates might be able to provide further engineering rationale. Also IIRC the 380F max is a Mike Busch recommendation as a working max. Not a constraint to optimize against. So I generally try to keep them significantly lower if I can. My understanding is that, unless things are "too cool" (in terms of deposits), cylinder longevity is better with lower CHTs, for metallurgic reasons. This is my non-specialist's take on things. 1
Schllc Posted February 24 Report Posted February 24 I seldom see much higher than 350. When that is exceeded it’s usually because of extended ground time and high oat. even then tit’s for me are in the mid to high 1400’s. I get running the fuel rich for cht’s but if cht’s are 350ish with tit in the 1400’s. What is the purpose of sending more fuel through the exhaust? I don’t understand the benefit of 1300’s in the climb. I am not challenging the assertion, just don’t understand the reason behind it.
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