Oil analysis -- where?
Joined: Jan 1999
Posts: 6,209
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From: north of barlu
Correct Peter but I just apply to myself!
Returning to the subject of the thread we use Intertec for spectro checking oil samples.
Intertek Farnborough FLC
Returning to the subject of the thread we use Intertec for spectro checking oil samples.
Intertek Farnborough FLC
Last edited by A and C; 22nd January 2012 at 19:01.
Joined: Mar 2010
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From: Up North
A and C
Thanks for that, one more question if I may.
If a club aircraft does a lot of shorter (ie 15/20/30 mins) trial lessons, then the actual engine running time could be double what's entered in the tech. log and engine log book. Whereas, if it's doing IMCr training or longer cross-country trips, then the engine on time may only be 10% longer than the "flight" time. Would you say this should have an effect?
Also, does the cruise power setting (55%, 65%, 75%?) you regularly operate at have any effect?
Okay that's two I know, sorry.
Thanks for that, one more question if I may.
If a club aircraft does a lot of shorter (ie 15/20/30 mins) trial lessons, then the actual engine running time could be double what's entered in the tech. log and engine log book. Whereas, if it's doing IMCr training or longer cross-country trips, then the engine on time may only be 10% longer than the "flight" time. Would you say this should have an effect?
Also, does the cruise power setting (55%, 65%, 75%?) you regularly operate at have any effect?
Okay that's two I know, sorry.
Joined: Dec 2011
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The old debate of what time to log 
For pilot logbook purposes, one logs brakes off to brakes on.
For aircraft maintenance purposes, one logs airborne time. That is good enough for the oil.
Where you don't quite trust people who fly the plane to tell the truth about the time, you might log "hobbs time" or whatever some cockpit instrument logs, which could be time with the oil pressure above X PSI, time above 1200rpm, or just a count of engine revolutions adjusted to hours at some standard RPM e.g. 2300.
Re power, nobody will really agree on this but I think there is a sort of consensus that 65% is the best power setting for a long engine life.
For pilot logbook purposes, one logs brakes off to brakes on.
For aircraft maintenance purposes, one logs airborne time. That is good enough for the oil.
Where you don't quite trust people who fly the plane to tell the truth about the time, you might log "hobbs time" or whatever some cockpit instrument logs, which could be time with the oil pressure above X PSI, time above 1200rpm, or just a count of engine revolutions adjusted to hours at some standard RPM e.g. 2300.
Re power, nobody will really agree on this but I think there is a sort of consensus that 65% is the best power setting for a long engine life.
Joined: Jan 1999
Posts: 6,209
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From: north of barlu
Mrmum
I don't think that the engine running time at low power settings has much effect on the engine life.
Flying at moderate power settings 60-65% power and slightly RoP is the best way to get an engine to TBO with the least maintenance cost. Settings of lower than 60% are good for endurance but are likely to result in high oil consumption due to the piston rings sticking and the cost of getting this fixed.
The very worst thing for engines is high power followed by rapid low power decents, an unskilled glider tug pilot could wreck a set of cylinders in no time. Fortunately the BGA has done a lot of work in this area and issued guidance to minimize the dangers of shock cooling but this is still the most hostile environment for an air cooled engine to operate in.
For the private owner operating at 75% power LoP is likely to be the most economical way to fly, the higher speed and shorter time in the air will keep the flight time based maintenance cost per ground mile down, being the only operator of the aircraft it is likely that he would be competent at mixture control and with fuel in Europe so expensive the savings running LoP are likely to more than pay for new cylinders at half TBO.
Flying at moderate power settings 60-65% power and slightly RoP is the best way to get an engine to TBO with the least maintenance cost. Settings of lower than 60% are good for endurance but are likely to result in high oil consumption due to the piston rings sticking and the cost of getting this fixed.
The very worst thing for engines is high power followed by rapid low power decents, an unskilled glider tug pilot could wreck a set of cylinders in no time. Fortunately the BGA has done a lot of work in this area and issued guidance to minimize the dangers of shock cooling but this is still the most hostile environment for an air cooled engine to operate in.
For the private owner operating at 75% power LoP is likely to be the most economical way to fly, the higher speed and shorter time in the air will keep the flight time based maintenance cost per ground mile down, being the only operator of the aircraft it is likely that he would be competent at mixture control and with fuel in Europe so expensive the savings running LoP are likely to more than pay for new cylinders at half TBO.
Joined: Mar 2010
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From: Up North
A and C, thank you 
Peter, I wasn't actually asking what or how to log times, I'm pretty clear on that thanks. Was just looking for an engineering perspective on the effects if any of taxi time on the engine. However, as you say, it's always nice to see old favourites from time to time.
What's the best headset and GPS?
Peter, I wasn't actually asking what or how to log times, I'm pretty clear on that thanks. Was just looking for an engineering perspective on the effects if any of taxi time on the engine. However, as you say, it's always nice to see old favourites from time to time.
What's the best headset and GPS?
