Arrow climb power - 25-squared?
- Thread starter nanjason
- Start date
Alchemy
Well-Known Member
I'm aware of this JT, which is why I've been prohibited from performing the initial power reduction in a turn. While it is important to have adequate altitude before reducing power, I'd venture to say that 500 ft is a good enough compromise between the risk of having a power reduction induced engine failure and minimizing the time spent redlining the engines in a light twin. Speaking of which, do you ever synch up the props before your 1000 AGL power reduction? The seneca I'm flying doesn't sync up very well at all with props full forward and full throttle. It would seem almost unnatural to climb all the way to 1000 AGL (around 1.5-2 mins of flight time) with the props red lined and out of sync like that.
I'll approach my CFI with some of these articles (thanks Ed) and see what he has to say, but I'm not going to ditch a CFI who I've already flown 150+ hours dual and passed 3 checkrides with because of this one engine managment issue, important as it may be. It's not as if he's pulling this stuff out of his @ss, he was trained at ATP less than 2 years ago so I can only assume that's the way they teach things there, wrong or right.
I appreciate the help John, annonman, everyone else and sorry for semi-hijacking your thread Ed.
I'll approach my CFI with some of these articles (thanks Ed) and see what he has to say, but I'm not going to ditch a CFI who I've already flown 150+ hours dual and passed 3 checkrides with because of this one engine managment issue, important as it may be. It's not as if he's pulling this stuff out of his @ss, he was trained at ATP less than 2 years ago so I can only assume that's the way they teach things there, wrong or right.
I appreciate the help John, annonman, everyone else and sorry for semi-hijacking your thread Ed.
Mr_Creepy
Well-Known Member
I sync the props early in the takeoff roll, well before my abort (go - nogo) point.
As you pointed out before, most light twins are certified for max power continuously, therefore:
I sincerely advise against considering 500' AGL as a safe altitude in a Seneca, especially a I or a II. Those tubs DO NOT maintain altitude on one engine, particulary on a hot day in FL.
Take it to 1000' - you'll be glad you did someday
Here is a "mantra" for light twin operators: Say "red, yellow, green" to yourself before every takeoff. It will remind you of these points:
1) Red zone. Before v1 or abort point. Anything happens I abort immediately.
2) Yellow Zone. Starts when you take your hand of the throttles and go for the gear. No more runway left, so anything happens, immediate feather.
3) Green Zone. 1000' AGL. Anything happens, pull out the checklist and see what you can do. You have enough altitude to do some maneuvering and should be able to make it back to the airport in almost all situations.
This will save lives. It already has, come to think of it.
As you pointed out before, most light twins are certified for max power continuously, therefore:
I sincerely advise against considering 500' AGL as a safe altitude in a Seneca, especially a I or a II. Those tubs DO NOT maintain altitude on one engine, particulary on a hot day in FL.
Take it to 1000' - you'll be glad you did someday
Here is a "mantra" for light twin operators: Say "red, yellow, green" to yourself before every takeoff. It will remind you of these points:
1) Red zone. Before v1 or abort point. Anything happens I abort immediately.
2) Yellow Zone. Starts when you take your hand of the throttles and go for the gear. No more runway left, so anything happens, immediate feather.
3) Green Zone. 1000' AGL. Anything happens, pull out the checklist and see what you can do. You have enough altitude to do some maneuvering and should be able to make it back to the airport in almost all situations.
This will save lives. It already has, come to think of it.
Tired
New Member
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My Instructor really jumps my case if I leave the manifold higher than the RPM for any reason, even if it's less than a 1" difference for a second while I'm synchronizing the props or something.
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I'm aware of this JT, which is why I've been prohibited from performing the initial power reduction in a turn.
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Get a new instructor. I'll bet this guy doesn't let you extend the flaps while turning either.
My Instructor really jumps my case if I leave the manifold higher than the RPM for any reason, even if it's less than a 1" difference for a second while I'm synchronizing the props or something.
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I'm aware of this JT, which is why I've been prohibited from performing the initial power reduction in a turn.
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Get a new instructor. I'll bet this guy doesn't let you extend the flaps while turning either.
Tired
New Member
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1) Red zone. Before v1 or abort point. Anything happens I abort immediately.
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Good idea, except on a short runway, where the available distance is close to the accelerate-stop distance I pick a speed a good 15-20 knots below the abort speed, after which I will only abort for an engine failure or loss of directional control. It would be stupid to abort for something like an alternator light and then run off the end of the runway. Also, make sure you're calculating the abort speed correctly. If you fly the Seminole it is NOT 75 knots.
1) Red zone. Before v1 or abort point. Anything happens I abort immediately.
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Good idea, except on a short runway, where the available distance is close to the accelerate-stop distance I pick a speed a good 15-20 knots below the abort speed, after which I will only abort for an engine failure or loss of directional control. It would be stupid to abort for something like an alternator light and then run off the end of the runway. Also, make sure you're calculating the abort speed correctly. If you fly the Seminole it is NOT 75 knots.
Alchemy
Well-Known Member
Interesting that you adjust the props in the takeoff roll. I've had comments from people who were watching me on the ground about how bad the plane sounded when taking off. I am flying a 1972 seneca I (200 horse) I so I know what you mean about climbing on one engine. However, I usually have no problem maintaing altitude on one engine as high as 4500 ft MSL with the failed engine feathered, and can get a modest 50-100 fpm climb out if it during sim. engine failures in the traffic pattern (1500 MSL) with the prop windmilling and 12" of MP. In any event, obtaing 1000 feet AGL before reducing MP seems to make a lot of sense, especially if you sync the props up earlier. The "climb" section of the seneca POH states (and I quote).
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The best rate of climb speed (105 MPH at seat level) should be maintained with full power on the engines until approximately 500 feet AGL. The best rate of climb speed decreases slightly with incread density altitude and the best angle of climb speed incerases slightly. There is no time limit on full power engine operation. However, since full power requires a high fuel consumption and is unnecesary in most flight situations, it is advisabvle to reduce to a climb power setting any time after 500 feet AGL. Wen reducing power, the throttle should be retarded first, then the propeller controls. An enroute climb speed of 120 MPH provides good visiblity, climb perofrmance and engine cooling.
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Their choice of words in saying "any time after 500 feet" seems to imply flexibility in the altitude at which the power reduction should take place.
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The best rate of climb speed (105 MPH at seat level) should be maintained with full power on the engines until approximately 500 feet AGL. The best rate of climb speed decreases slightly with incread density altitude and the best angle of climb speed incerases slightly. There is no time limit on full power engine operation. However, since full power requires a high fuel consumption and is unnecesary in most flight situations, it is advisabvle to reduce to a climb power setting any time after 500 feet AGL. Wen reducing power, the throttle should be retarded first, then the propeller controls. An enroute climb speed of 120 MPH provides good visiblity, climb perofrmance and engine cooling.
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Their choice of words in saying "any time after 500 feet" seems to imply flexibility in the altitude at which the power reduction should take place.
Tired
New Member
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I sync the props early in the takeoff roll, well before my abort (go - nogo) point.
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Why are you're props out of sync on takeoff roll? Shouldn't they both be comming up to 2700RPM? I've never took of in a multi where the props were almost exactly the same RPM with the props full forward. Even if the aren't in sync why bother on takeoff roll, I personally wouldn't take my hands off the throttles until it's time to gear up.
I sync the props early in the takeoff roll, well before my abort (go - nogo) point.
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Why are you're props out of sync on takeoff roll? Shouldn't they both be comming up to 2700RPM? I've never took of in a multi where the props were almost exactly the same RPM with the props full forward. Even if the aren't in sync why bother on takeoff roll, I personally wouldn't take my hands off the throttles until it's time to gear up.
Alchemy
Well-Known Member
Speaking for myself, the tachs show almost exactly 2700 RPM on both engines during the roll with props full forward, but my ears tell a different story. Because of the sound, I could see the need for a slight 10 or 20 RPM adjustment on one engine (weather this is a tachometer calibration problem or just something inherent to the airplane I'm not sure). Then again, you do have a point about keeping your hands on the throttles at all times during takeoff.....not much time to pull the power back before you plow off the runway if you have a failure before vmc.
Mr_Creepy
Well-Known Member
I see your point but remember that's the red zone and the question is:
Do you have time to determine what's wrong? or do you just abort and let the mechanic take care of it.
If I can land straight ahead I'll do it!
Totally different than a turbo type airliner, where high speed aborts are very dangerous, but you also have significantly better single engine climb rate.
Do you have time to determine what's wrong? or do you just abort and let the mechanic take care of it.
If I can land straight ahead I'll do it!
Totally different than a turbo type airliner, where high speed aborts are very dangerous, but you also have significantly better single engine climb rate.
Alchemy
Well-Known Member
After reading all those deakin articles again (I had read them at least once before this thread), it is pretty apparant that running the engine at full throttle and some reduced RPM will not hurt the engine unless you take it to the point where detonation occurs (The cylinders can't displace as much volume during their power strokes, so combustion pressure and correspondigly temperature increases). Deakin does mention that the "old rule of thumb" of reducing manifold before rpm and increasing rpm before manifold isn't bad and is in fact "a good habit". It's just unecessary for the vast majority of power adjustments since there isn't a risk of detonation unless you have have a fairly large discrepency between MP and RPM. The CHT/EGT gauge should quickly let you know if you're getting into the range where detonation could occur.
As far as leaving the engine at full throttle for the entire climbout, it seems like it would be perfectly acceptable assuming you compensated for the increased fuel consumption in your flight planning. Deakin argues that climbing out with full throttle and simply reducing the RPM to 2500 is easier on the engines, since his engine has a "power enrichment valve" which greatly increases fuel flow and cools the engine at full throttle, but not at reduced throttle settings. I do not know for certain if the aircraft I fly have a "power enrichment valve", but if they do the initial power reduction actually leans the mixture quite a bit, correspondingly increasing engine temperatures. I would imagine the IO-540 in the 182 does have this feature, but am unsure about the smaller IO-360's in the seneca. In any event I have printed out all 5 of those articles (68 pages of material) and will ask my CFI to read them.
As far as leaving the engine at full throttle for the entire climbout, it seems like it would be perfectly acceptable assuming you compensated for the increased fuel consumption in your flight planning. Deakin argues that climbing out with full throttle and simply reducing the RPM to 2500 is easier on the engines, since his engine has a "power enrichment valve" which greatly increases fuel flow and cools the engine at full throttle, but not at reduced throttle settings. I do not know for certain if the aircraft I fly have a "power enrichment valve", but if they do the initial power reduction actually leans the mixture quite a bit, correspondingly increasing engine temperatures. I would imagine the IO-540 in the 182 does have this feature, but am unsure about the smaller IO-360's in the seneca. In any event I have printed out all 5 of those articles (68 pages of material) and will ask my CFI to read them.
pilot602
If specified, this will replace the title that
[ QUOTE ]
As far as leaving the engine at full throttle for the entire climbout, it seems like it would be perfectly acceptable assuming you compensated for the increased fuel consumption in your flight planning. Deakin argues that climbing out with full throttle and simply reducing the RPM to 2500 is easier on the engines, since his engine has a "power enrichment valve" which greatly increases fuel flow and cools the engine at full throttle, but not at reduced throttle settings.
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I misspoke when I said "save wear and tear" on the engines with a 25/25 climb out. The engine is desinged to run all day long at redline. It's just not the most efficient way of running it (fuel consumption wise). Most engines don't have a specific valve concerning mixture setting at full power - but most if not all are calibrated to run a little on the rich side when the throttle is open and the mixture is full rich (mixture can be adjusted at the engine via a set screw and is independent of the mixture control).
We bring our engines back to 25/25 because of the intense ambient temperatures here in AZ. Vy is 100mph but we routinely climb at 110-120 mph with reduced power settings. By doing this wee keep our cylinder head temps low and thereby save "wear and tear" on the engine.
As far as leaving the engine at full throttle for the entire climbout, it seems like it would be perfectly acceptable assuming you compensated for the increased fuel consumption in your flight planning. Deakin argues that climbing out with full throttle and simply reducing the RPM to 2500 is easier on the engines, since his engine has a "power enrichment valve" which greatly increases fuel flow and cools the engine at full throttle, but not at reduced throttle settings.
[/ QUOTE ]
I misspoke when I said "save wear and tear" on the engines with a 25/25 climb out. The engine is desinged to run all day long at redline. It's just not the most efficient way of running it (fuel consumption wise). Most engines don't have a specific valve concerning mixture setting at full power - but most if not all are calibrated to run a little on the rich side when the throttle is open and the mixture is full rich (mixture can be adjusted at the engine via a set screw and is independent of the mixture control).
We bring our engines back to 25/25 because of the intense ambient temperatures here in AZ. Vy is 100mph but we routinely climb at 110-120 mph with reduced power settings. By doing this wee keep our cylinder head temps low and thereby save "wear and tear" on the engine.
ready2fly
Well-Known Member
Ditto what Pilot602 said. In the Travel Air, after we've got a positive rate of climb, have retracted gear and have cleared all obsticals, we pull the Throttles/Props back to 25/25 until we reach altitude.
The way it was explained to me is that we **could** leave the RPM/Prop settings at full until we reach altitude and it wouldn't cause any damage to the engines, but for fuel consumption, 25/25 seems to be the best value. Anthing over that is a needless buring of fuel/oil.
Any thoughts?
The way it was explained to me is that we **could** leave the RPM/Prop settings at full until we reach altitude and it wouldn't cause any damage to the engines, but for fuel consumption, 25/25 seems to be the best value. Anthing over that is a needless buring of fuel/oil.
Any thoughts?
ready2fly
Well-Known Member
Lycoming O-360's.... I believe. 180 horses each.
Got to admit - I LOVE the way the thing flies!! You're up at 4000 in NO time!!
What I don't like about it is that the yoke is WAY to close to my body (it's one of those centrally mounted systems with a "T-Bar" kind of configuration) and the Props and Throttles levers are reversed... as are the flaps and gear levers from normal light twins.
Other'n that though - as I've had approximately ZERO experience in any other kind of light twin - I LOVE IT LOVE IT LOVE IT!!!
Got to admit - I LOVE the way the thing flies!! You're up at 4000 in NO time!!
What I don't like about it is that the yoke is WAY to close to my body (it's one of those centrally mounted systems with a "T-Bar" kind of configuration) and the Props and Throttles levers are reversed... as are the flaps and gear levers from normal light twins.
Other'n that though - as I've had approximately ZERO experience in any other kind of light twin - I LOVE IT LOVE IT LOVE IT!!!
pilot602
If specified, this will replace the title that
180s are nice. We're pushing 160s and can hold almost a 1,000-1,200 FPM climb even on the warm days - but at about 3,000 agl it starts dropping.
What's the SEC?
I'm kinda surprised you're in a travel air ... kind of a rare airplane anymore ... let alone for training. Neat looking aircraft though.
What's the seating like in it? (number etc.)
Counter rotating or do you have a critical engine?
Gross weight?
Heh I guess you could just describe it and be done with it!
What's the SEC?
I'm kinda surprised you're in a travel air ... kind of a rare airplane anymore ... let alone for training. Neat looking aircraft though.
What's the seating like in it? (number etc.)
Counter rotating or do you have a critical engine?
Gross weight?
Heh I guess you could just describe it and be done with it!
ready2fly
Well-Known Member
[ QUOTE ]
What's the SEC?
I'm kinda surprised you're in a travel air ... kind of a rare airplane anymore ... let alone for training. Neat looking aircraft though.
What's the seating like in it? (number etc.)
Counter rotating or do you have a critical engine?
Gross weight?
[/ QUOTE ]
Okay, here goes:
-1959 BE95/Travel Air
-Lycoming O-360's with 180 horses/per.
-Has a critical engine, so I'll be a Vmc flyin' fool.
-Gross weight... damn - I knew that when I came in here.
-SEC is 190 fpm
-Vyse is 102 mph (remember, it's an old plane, so mph instead of kts)
-Takeoff distance is 2300 feet
-Accelerate to stop distance is 2600 feet
-landing distance is 1620 feet
- Vne is 185 mph
-Vno is .... lower
-Vmc is 80-85
Downwind speed = 110 KIAS (have to kind of do the conversion by looking at the ASI)
Base = 100 KIAS
Final = 90 KIAS
I love flying the thing. It's a LOT heavier than what I'm used to, but MAN is it smooth!!!
Nice to see the ground move under me.
pilot602
If specified, this will replace the title that
Cool not much different than the Apache:
in case you're curious;
-1961 Apache 160"G"
-Lycoming O-320(B)s with 160 horses/per.
-Non Counter-rotating
-Gross weight: 3,800 Lbs. Empty Weight 2,460lbs.. Useful load after a full tank(s) of 108 Gal. of fuel: 700+/- pounds.
(now you know where the "Aztruck" got its roots)
-SEC (single engine celing: 5,500ft. @ gross) Climb 200fpm @ gross
-Vyse is 95 mph (I know all about mph!
)
-Takeoff distance is 1200ft. @ gross, 1550ft. over 50 ft obstacle
-Accelerate to stop distance is 2000 ft (rough estiamate)
-Landing distance 750ft. (if you're sloppy), 1360ft. over 50 ft. obstacle
-Vne is 227mph (like we could ever even get close to that)
-Vno is 185mph if I remember correctly (in full-out operation the fastest it will indicate in level cruise is about 160mph normal cruise indicates about 120-30mph which trues to about 150-60mph or 130kts.)
-Vle is 150 mph
-Vfe is 125 mph
-Vmc is 72mph
-Vso is 56 mph (slow flight is fun at 60mph!
)
-Downwind speed = 110 mph
-Base = 100 mph (17" m.p.)
-Final = 90 mph (15" m.p.) for short field landings we'll fly 80 mph.
Pretty similar actually!
in case you're curious;
-1961 Apache 160"G"
-Lycoming O-320(B)s with 160 horses/per.
-Non Counter-rotating
-Gross weight: 3,800 Lbs. Empty Weight 2,460lbs.. Useful load after a full tank(s) of 108 Gal. of fuel: 700+/- pounds.
-SEC (single engine celing: 5,500ft. @ gross) Climb 200fpm @ gross
-Vyse is 95 mph (I know all about mph!
-Takeoff distance is 1200ft. @ gross, 1550ft. over 50 ft obstacle
-Accelerate to stop distance is 2000 ft (rough estiamate)
-Landing distance 750ft. (if you're sloppy), 1360ft. over 50 ft. obstacle
-Vne is 227mph (like we could ever even get close to that)
-Vno is 185mph if I remember correctly (in full-out operation the fastest it will indicate in level cruise is about 160mph normal cruise indicates about 120-30mph which trues to about 150-60mph or 130kts.)
-Vle is 150 mph
-Vfe is 125 mph
-Vmc is 72mph
-Vso is 56 mph (slow flight is fun at 60mph!
-Downwind speed = 110 mph
-Base = 100 mph (17" m.p.)
-Final = 90 mph (15" m.p.) for short field landings we'll fly 80 mph.
Pretty similar actually!
