TSIO 360 leaning questions.
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While flooded hot starts do seem to work for some engines, remember that it carries the very real risk of a fire.
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Walter said:
Adding to your excellent post, I'd like to point out that the "flooded start" is a widespread technique that almost always works, and proponents will invariably shout down the nay-sayers (like you and me), ending up with something like "I've been doing it for 150 years, and I've never had a fire!"
Not so.
Induction fires are very common with flooded starts, but are very seldom detected, being buried deep in the engine, and they are sucked harmlessly into the engine - where there is supposed to be fire. That's more or less harmless, and the reason SOME manuals have a note.
But consider the case where, for whatever reason, it doesn't work, and you pause for a bit to consider your options. You may have a puddle of fuel under the engine in the cowl, or on the ramp, or puddled in the induction manifold, and depending on a lot of things, it may or may not light off. Even if it does, you may still be lucky, and avoid further complications. There may not be enough fuel, there may not be the precipitating spark, or you may go ahead and crank again, sucking it into the engine, totally unaware of how close to disaster you might have been.
I learned this lesson early. In about 1956 (I was about 17), I was flying a Lambert 90A Monocoupe (antique, even then) and had stopped in Venice, Florida for some reason, and jumped right back in the airplane to start it up again. I flubbed the start, and stopped to give it a chance to air out.
I heard a cry of "FIRE!" and looked to see where the call had come from, never dreaming of the reality. Someone about 100 yards away, and he was pointing directly at ME! Still dim-witted, I looked to the other side, and there was no one there. I opened the door and looked under the airplane, and sure enough, there was a merry little fire, just beginning to reach the greasy belly of the fabric covered airplane. I jumped out and pushed the airplane about 20 feet backwards, and luckily, there was no damage.
It was a HOT Florida day, with a ramp that was hot enough to fry eggs. The overflow converted to vapor very quickly, which created perfect conditions for the tiny backfire I'd had to light it off.
A very respected and senior airman burned up his airplane from a similar event a few years back, and barely got out. He was alone in the airplane. What if he'd had the wife and kids on board?
Mercifully, the wrong circumstances don't happen often.
Best...
John Deakin
While flooded hot starts do seem to work for some engines, remember that it carries the very real risk of a fire. More than a few aircraft have been lost to that indiscretion. Just because it has worked without a fire for many attempts does not assure that the next attempt will not burn the aircraft to the ground. For that reason, I no longer use the method--EVER.
Not so.
Induction fires are very common with flooded starts, but are very seldom detected, being buried deep in the engine, and they are sucked harmlessly into the engine - where there is supposed to be fire. That's more or less harmless, and the reason SOME manuals have a note.
But consider the case where, for whatever reason, it doesn't work, and you pause for a bit to consider your options. You may have a puddle of fuel under the engine in the cowl, or on the ramp, or puddled in the induction manifold, and depending on a lot of things, it may or may not light off. Even if it does, you may still be lucky, and avoid further complications. There may not be enough fuel, there may not be the precipitating spark, or you may go ahead and crank again, sucking it into the engine, totally unaware of how close to disaster you might have been.
I learned this lesson early. In about 1956 (I was about 17), I was flying a Lambert 90A Monocoupe (antique, even then) and had stopped in Venice, Florida for some reason, and jumped right back in the airplane to start it up again. I flubbed the start, and stopped to give it a chance to air out.
I heard a cry of "FIRE!" and looked to see where the call had come from, never dreaming of the reality. Someone about 100 yards away, and he was pointing directly at ME! Still dim-witted, I looked to the other side, and there was no one there. I opened the door and looked under the airplane, and sure enough, there was a merry little fire, just beginning to reach the greasy belly of the fabric covered airplane. I jumped out and pushed the airplane about 20 feet backwards, and luckily, there was no damage.
It was a HOT Florida day, with a ramp that was hot enough to fry eggs. The overflow converted to vapor very quickly, which created perfect conditions for the tiny backfire I'd had to light it off.
A very respected and senior airman burned up his airplane from a similar event a few years back, and barely got out. He was alone in the airplane. What if he'd had the wife and kids on board?
Mercifully, the wrong circumstances don't happen often.
Best...
John Deakin
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Walter and John are absolutely correct. DON'T do it. I was taught that method and it worked fairly well for 20 years when suddenly.............
I was starting a heat soaked IO 520 at Fitzroy Crossing and it was being cantankerous so I stopped the starting procedure ,flooded it a bit more and then continued using the starter. It did a small backfire and the fuel guy got real excited. He grabbed the extinguisher and poured foam into the engine compartment.
The fire started in the inlet manifold and the backfire ignited the fuel fume soaked air filter. 24 hours later sporting one brand new air filter we were on our way. We were very lucky.
Once again it was a case of OWTs being handed down by people who didn't know better and like me had got away with the method for a long time.
I now use the Cessna Pilots Association method for hot starts. It's not only safe but it's much more reliable.
Cheers RA
I was starting a heat soaked IO 520 at Fitzroy Crossing and it was being cantankerous so I stopped the starting procedure ,flooded it a bit more and then continued using the starter. It did a small backfire and the fuel guy got real excited. He grabbed the extinguisher and poured foam into the engine compartment.
The fire started in the inlet manifold and the backfire ignited the fuel fume soaked air filter. 24 hours later sporting one brand new air filter we were on our way. We were very lucky.
Once again it was a case of OWTs being handed down by people who didn't know better and like me had got away with the method for a long time.
I now use the Cessna Pilots Association method for hot starts. It's not only safe but it's much more reliable.
Cheers RA
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The risk mitigation for engine fire is to keep cranking it and keep the fire to where it should be!
I don't know if anyone has had a look at the priming time graph supplied with the POH, but in Australia, it is realistic to expect to prime the engine to anywhere between 8-14 seconds when it's cold (0 degrees C ambient temp) to 6-8 seconds in warmer ambient temp.
Now, quick survery for those that have flown the Seneca, what happens after about 3 seconds of holding in the primer buttons...?!
I don't know if anyone has had a look at the priming time graph supplied with the POH, but in Australia, it is realistic to expect to prime the engine to anywhere between 8-14 seconds when it's cold (0 degrees C ambient temp) to 6-8 seconds in warmer ambient temp.
Now, quick survery for those that have flown the Seneca, what happens after about 3 seconds of holding in the primer buttons...?!
Are you referring to the overboard fuel vent, this will occur if the fuel pumps are left on with the engine not turning as well.
EB, Priming 5 seconds warm and 10 seconds cold always seemed to work (without primer buttons). With the primer, hitting it during start usually got it going if stubborn, and the occasional tap until stable.
The RBs only liked a very small prime when hot, but a good dose needed when cold.
Works in most but have still seen an instructor BBQ a Warrior even with cranking after using the throttle to prime it, followed by more pumping during cranking. Had to abandon and use the extinguisher.
EB, Priming 5 seconds warm and 10 seconds cold always seemed to work (without primer buttons). With the primer, hitting it during start usually got it going if stubborn, and the occasional tap until stable.
The RBs only liked a very small prime when hot, but a good dose needed when cold.
The risk mitigation for engine fire is to keep cranking it and keep the fire to where it should be!
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I don't know about all the other silent readers of this thread (and the other threads about engine management), but I have found this discussion extremely valuable. Education in this area during my training was poor to non-existent. I certainly want to find time to get to one of Jaba's classes when they are next being run in my area.
Thumbs up for pprune dunnunda.
Thumbs up for pprune dunnunda.
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Are you referring to the overboard fuel vent, this will occur if the fuel pumps are left on with the engine not turning as well.
Most Senecas I have flown start dumping fuel overboard after about 3 seconds of priming...
Akro,
Gold. There isn't a twin owner out there that hasn't at some point stood there looking at their plane war-gaming how it would go!
My understanding is that the optional primer buttons allow a higher flow rate using the hi-flow pump in the alternate system. That is primer equiped aircraft have the Hi-Lo fuel pumps. This is why priming using pumps is longer, low flow rate only on non primer installed aircraft.
In the non-primer Seneca II aircraft losing the mechanical pump results in only 25% available power through the aux pump. With the alternate system approx 75% is available through the Hi pump and Lo is used for vapour suppression.
The cold weather start procedure has the fuel pumps on low continuously and using prime buttons as well during cranking, and then as needed until stable operation.
In the non-primer Seneca II aircraft losing the mechanical pump results in only 25% available power through the aux pump. With the alternate system approx 75% is available through the Hi pump and Lo is used for vapour suppression.
The cold weather start procedure has the fuel pumps on low continuously and using prime buttons as well during cranking, and then as needed until stable operation.
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Education in this area during my training was poor to non-existent. I certainly want to find time to get to one of Jaba's classes when they are next being run in my area.
Last year I was hammered by requests to do a class in Sydney. Wild promises and all that. So we did. If you consider one husband and wife team as ONE, and a Melbourne course student who at the last minute had baby sitting issues, and was lucky to have the next one in her home town, then there were only two Sydney bookings out of the whole class.
Yes how sad.....we had several folk from Tasmania, Queensland, NW NSW and Broome WA.
What was the frustrating thing, that all the folk who badgered me to put one on in Sydney, at greater expense I might add, and poorer venue quality, was that not one of them was one of the two that was there.
So in future we will run dedicated closed courses for organisations like the one in Cairns in a couple of months or maybe in Perth, but otherwise they will be in Adelaide or Brisbane. Why? Well simply no matter where you hold them the majority have to travel anyway. You are away from home and the kids footy, wife chore list etc. And we can better control the quality of the venue.
We do not do them for the purpose of making money, so being careful not to burn ourselves is one thing, and when I think about it, the course is not cheap, but it is not outrageous either, so ensuring the delivery quality and venue quality is up to standard is the most important thing, otherwise the student suffers.
In short Tonym3, if you would be kind enough to email me I will put you on our email list for future courses and we would love to have you along. It is a great 3 days and lots of fun.
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Walter, John, Jaba
I went for a short fly yesterday. It was for another reason and I didn't have a sustained climb to experiment as much as I might have otherwise, but I set 35 / 2575 and tried to lean to the " Full Rich" figure in the KB engine chart - 67 litres / hr. The TIT was getting higher than I liked (probably would have settled over 1400 degF TIT). Instead I went back to the EB " Max Allowable - full Rich" figure of about 70 litres / hr (might have been a bit more) and got a TIT of 1300 degF (might have been a bit more).
So, are CMI recommending something you you would not regard as best practice? Or is my idea that I could climb at 1250 - 1300 degF a bit too conservative?
I went for a short fly yesterday. It was for another reason and I didn't have a sustained climb to experiment as much as I might have otherwise, but I set 35 / 2575 and tried to lean to the " Full Rich" figure in the KB engine chart - 67 litres / hr. The TIT was getting higher than I liked (probably would have settled over 1400 degF TIT). Instead I went back to the EB " Max Allowable - full Rich" figure of about 70 litres / hr (might have been a bit more) and got a TIT of 1300 degF (might have been a bit more).
So, are CMI recommending something you you would not regard as best practice? Or is my idea that I could climb at 1250 - 1300 degF a bit too conservative?
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Akro,
I would like to see what Walter and John have to say here, and as previously stated my Seneca experience is limited to very little, but in my opinion the following apply;
1. 67 LPH is not enough, and the over 1400dF EGT supports this, assuming timing is accurate.
2. You are possibly being a bit too conservative, for a low compression turbo I would expect a EGT (cylinder EGT) of around 1350-1370 and a TIT of a touch more. But not over 1400.
So I guess you could split the difference.
Let's see if John or Walter have any suggestions overnight.
Cheers
DB
I would like to see what Walter and John have to say here, and as previously stated my Seneca experience is limited to very little, but in my opinion the following apply;
1. 67 LPH is not enough, and the over 1400dF EGT supports this, assuming timing is accurate.
2. You are possibly being a bit too conservative, for a low compression turbo I would expect a EGT (cylinder EGT) of around 1350-1370 and a TIT of a touch more. But not over 1400.
So I guess you could split the difference.
Let's see if John or Walter have any suggestions overnight.
Cheers
DB
Hi Old Akro
It's been a few years since I've flown a Seneca and I can't remember fuel flows, power settings etc., but I currently get to fly between a couple of intercooled, twin turbo'd IO-540's every now and then.
The aeroplane has it's stock engine instrumentation, but there are no EGT gauges. Just a couple of TIT and fuel flow gauges.
Takeoff power shows up as 42" and 2500RPM with the fuel flow sitting on 175l/h per side. The TIT hovers around 1250°F or a bit more. I normally set climb power at 38" and 2400RPM. If the mixture is left full rich the TIT drops back to a bit over 1200°F and the fuel flow settles on 160l/h per engine.
However, I find that some times if the mixture is left full rich in the climb (the POH states full rich anytime you're above 75%), the aeroplane leaves long trails of black smoke everywhere it goes. It was enough for someone who knows the aeroplane to give me a call one day as I climbed out, suggesting that I had an engine fire!
For me, that indicates that the engines are running far too rich. With climb power dialled up I'll pull the mixtures back slightly, looking for 1350°F on the TIT's. The fuel flow comes back to a more reasonable 150l/h (although at 300l/h total, some might say that's still very unreasonable). I never have a problem with CHT's at any of the above power settings. The CHT sits rock solid on 320° in the climb all the way to FL200. It's only when the aeroplane gets above this altitude and the wastegates are fully closed, that the CHT might drift up to and nudge 340°F. That's still way below 400°F and I feel comfortable with that CHT at high altitude.
I realise I'm not talking TCM IO-360's here, but you were mentioning TIT's so I thought I'd compare notes.GB.
It's been a few years since I've flown a Seneca and I can't remember fuel flows, power settings etc., but I currently get to fly between a couple of intercooled, twin turbo'd IO-540's every now and then.
The aeroplane has it's stock engine instrumentation, but there are no EGT gauges. Just a couple of TIT and fuel flow gauges.
Takeoff power shows up as 42" and 2500RPM with the fuel flow sitting on 175l/h per side. The TIT hovers around 1250°F or a bit more. I normally set climb power at 38" and 2400RPM. If the mixture is left full rich the TIT drops back to a bit over 1200°F and the fuel flow settles on 160l/h per engine.
However, I find that some times if the mixture is left full rich in the climb (the POH states full rich anytime you're above 75%), the aeroplane leaves long trails of black smoke everywhere it goes. It was enough for someone who knows the aeroplane to give me a call one day as I climbed out, suggesting that I had an engine fire!
For me, that indicates that the engines are running far too rich. With climb power dialled up I'll pull the mixtures back slightly, looking for 1350°F on the TIT's. The fuel flow comes back to a more reasonable 150l/h (although at 300l/h total, some might say that's still very unreasonable). I never have a problem with CHT's at any of the above power settings. The CHT sits rock solid on 320° in the climb all the way to FL200. It's only when the aeroplane gets above this altitude and the wastegates are fully closed, that the CHT might drift up to and nudge 340°F. That's still way below 400°F and I feel comfortable with that CHT at high altitude.
I realise I'm not talking TCM IO-360's here, but you were mentioning TIT's so I thought I'd compare notes.GB.
Thread Starter
the aeroplane leaves long trails of black smoke everywhere it goes.
If you have ever read the fuel flow adjustment procedure for a turbocharged engine it is quite complex, time consuming and requires calibrated gauges. I believe that hardly any LAME's do this and I suspect that few actually have the proper calibrated gauge set up. They just tweak it from the last position and ask the owner to report back. Proper adjustment requires full power climbs to the critical altitude - when is the last time that was done as part of a 100 hourly??.
But, I also think I'm discovering that the Continental fuel flow curves don't match (ie conflict with) some of their other specified operating limitations. This is the sort of thing that might happen if some data (ie the fuel flow curves) came from dynamo-meter run with perfect cooling and some restrictions came from real world testing and some came from good old fashioned boiler plating by guys sitting behind desks wanting to be conservative and add safety factors. - Which is the point John Deakins has been making for years!
However, I find that some times if the mixture is left full rich in the climb (the POH states full rich anytime you're above 75%), the aeroplane leaves long trails of black smoke everywhere it goes. It was enough for someone who knows the aeroplane to give me a call one day as I climbed out, suggesting that I had an engine fire!
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Gassed budgie and 43"
I just had a quick peek at some data on that engine, and one that is properly set up
and the fuel flows when full rich were 42"/2570 = 154 LPH (40.5GPH) with a TIT of 1370dF and at 40"/2400 it was 136LPH (36GPH) with a TIT of 1300-1305dF.
You could do a rough scaling of this for 38/2400 and it would be 129-130LPH.
As 43" has mentioned with cold oil and cold atmosphere the density controllers will do their thing and they need to be set up right.
But one point to remember, and this applies to ALL ENGINES, no matter what, it is better to have a fuel delivery system slightly richer than slightly leaner Not drowning it though. Because no matter how hard you push the red knob in it will never flow more, but as the human FADEC you can control it back if need be. So be careful about having the LAME's reduce the flows unless they are ridiculous now. Better to have a fraction too much than too little.
All the best
DB
PS: If anyone wants to see this stuff and learn a heap, PM me your email address and I will keep you informed on when and where the next opportunity will be.
I just had a quick peek at some data on that engine, and one that is properly set up
and the fuel flows when full rich were 42"/2570 = 154 LPH (40.5GPH) with a TIT of 1370dF and at 40"/2400 it was 136LPH (36GPH) with a TIT of 1300-1305dF.You could do a rough scaling of this for 38/2400 and it would be 129-130LPH.
As 43" has mentioned with cold oil and cold atmosphere the density controllers will do their thing and they need to be set up right.
But one point to remember, and this applies to ALL ENGINES, no matter what, it is better to have a fuel delivery system slightly richer than slightly leaner Not drowning it though. Because no matter how hard you push the red knob in it will never flow more, but as the human FADEC you can control it back if need be. So be careful about having the LAME's reduce the flows unless they are ridiculous now. Better to have a fraction too much than too little.
All the best
DB
PS: If anyone wants to see this stuff and learn a heap, PM me your email address and I will keep you informed on when and where the next opportunity will be.
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LOL!
For whatever reason, it was an ICP problem.
i.e., Overboost; not rich enough ROP for the power setting; not lean enough LOP for the power setting; improper timing; pre-ignition, improper torque on the head--one or a combination of the aforementioned.
Whoever was running the engine wasn't paying attention. You could tell it was coming!
For whatever reason, it was an ICP problem.
i.e., Overboost; not rich enough ROP for the power setting; not lean enough LOP for the power setting; improper timing; pre-ignition, improper torque on the head--one or a combination of the aforementioned.
Whoever was running the engine wasn't paying attention. You could tell it was coming!