AS350 Astar / AS355 Twinstar [Archive Copy]
Avoid imitations
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The N is easier to start as it's almost completely automatic. The pilot still has to monitor the EGT though, there is no auto limiting during the start sequence so you are required to manually abort the start sequence if it gets too hot. Never seen it do that though, even after a shutdown and immediate restart, the Arrius is very good in that respect, far more stable than the Allison.
The engines can be started with the ECLs (read throttles) either at ground or fly if desired. BEWARE! If you do start them at fly (useful for scramble starts) you MUST ensure that the collective is locked down or you will find the aircraft getting airborne by itself, probably while you are pre-occupied starting the second engine and looking inside
Have fun flying it!
The engines can be started with the ECLs (read throttles) either at ground or fly if desired. BEWARE! If you do start them at fly (useful for scramble starts) you MUST ensure that the collective is locked down or you will find the aircraft getting airborne by itself, probably while you are pre-occupied starting the second engine and looking inside
Have fun flying it!
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Agree with Shytorque, make sure that the FADEC has got a grip of the T4 before you go on to do anything else. Occasionaly the FADEC will get a "Logic Lock" and not let you start an engine. The only answer is to shut everything down, switch off the batteries, count to 10 and have another go - usually cures it.
Enjoy
Enjoy
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Silly question - I've flown JetRangers for 35 minutes now and I thought the generator was the starter, and hence by definition it couldn't be online during the start. Please explain.
Avoid imitations
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The starter and generator are the same piece of kit. However, in the starter mode it is driving the engine but in the genny mode it is driven BY the engine, via the quill (= thin like a quill) shaft.
During the starting phase it will go off line completely once the self sustaining engine speed is reached, provided the generator switch is OFF.
If it goes straight from driving the engine to producing electrical power because the genny switch is left ON during engine start, the sudden load can cause the quill shaft to become over-torqued and fail (low engine speed = fewer volts = more Amps = more torque on the quill).
Hence the advice to leave the genny switch selected off during engine start. As I understand it, the Arrius engine has a thicker quill shaft so it's not likely to break.
Edited bit: [I should have mentioned that going from DRIVING the engine to being DRIVEN by the engine involves a reversal of the rotational torque load on the quill shaft; that's what can shear it
]
During the starting phase it will go off line completely once the self sustaining engine speed is reached, provided the generator switch is OFF.
If it goes straight from driving the engine to producing electrical power because the genny switch is left ON during engine start, the sudden load can cause the quill shaft to become over-torqued and fail (low engine speed = fewer volts = more Amps = more torque on the quill).
Hence the advice to leave the genny switch selected off during engine start. As I understand it, the Arrius engine has a thicker quill shaft so it's not likely to break.
Edited bit: [I should have mentioned that going from DRIVING the engine to being DRIVEN by the engine involves a reversal of the rotational torque load on the quill shaft; that's what can shear it
]
Last edited by ShyTorque; 16th Jul 2003 at 07:35.
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The biggest differences are not with the start on the N - that's a piece of cake. The new bits are the ways of dealing with governor failures, engine failures and what to look at when an engine stops (for real or in training mode).
The most important benefit is that you can carry both a decent fuel load and pax/baggage and still use helipads. The AS355N is a great piece of kit for public transport - not enough of them around in the UK unfortunately.
The most important benefit is that you can carry both a decent fuel load and pax/baggage and still use helipads. The AS355N is a great piece of kit for public transport - not enough of them around in the UK unfortunately.
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Yes too true helinut
6 big fat aussies 33deg C aircon on off the peninsula no problems
No unsafe area up to 2250KG (empty 1600kg) 7000'
Our new one arrives in mid september
fly safe
6 big fat aussies 33deg C aircon on off the peninsula no problems
No unsafe area up to 2250KG (empty 1600kg) 7000'
Our new one arrives in mid september
fly safe
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The 355N is a very understated helicopter. It does a good job in a quiet and unhurried way. Good for Corporate work. Better fuel burn if you can achieve above 4000 feet. I agree with the previous comments on the starting.
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The F1 is started with the Gennies on line in Canada - at least that was what I was taught on the factory course. Doing it the 206 way only serves to confuse everything and the generators go offline a lot more.
The reason for waiting a minute before switching the genny on in a Jetbox is so that the battery can settle down - and the extra amperage required if you don't doesn't draw fuel from the FCU and slow the engine - I've had more than one engineer tell me that the theory about the shaft breaking is complete b*ll*cks
I agree with the comments on the N model - very nice machine. You will find the engines very responsive in flight
phil
The reason for waiting a minute before switching the genny on in a Jetbox is so that the battery can settle down - and the extra amperage required if you don't doesn't draw fuel from the FCU and slow the engine - I've had more than one engineer tell me that the theory about the shaft breaking is complete b*ll*cks
I agree with the comments on the N model - very nice machine. You will find the engines very responsive in flight
phil
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Even though most of the times you start up without problems, I strongly recommed to pay very close attention if you are going to start with a tail wind. It may be scary and I've abborted a few of them when T4 was raising real fast very near the limits.
I've flown with only one engine and it's quite good, I can even tell you that she flies with both engines in TRAINING position, but for training pourposes makes you deal with much worse conditions than with a real engine failure.
We use it for fire fighting and mountain rescue and are quite happy with it, mostly when you take a look to performance in one engine in case you are hoisting a rescuer at the mountains. The weakest point to me is the electronic staff that every once in a while gives you a hard time but still less than what I've heard about the FADEC in B 407 or EC 135.
Buen vuelo
I've flown with only one engine and it's quite good, I can even tell you that she flies with both engines in TRAINING position, but for training pourposes makes you deal with much worse conditions than with a real engine failure.
We use it for fire fighting and mountain rescue and are quite happy with it, mostly when you take a look to performance in one engine in case you are hoisting a rescuer at the mountains. The weakest point to me is the electronic staff that every once in a while gives you a hard time but still less than what I've heard about the FADEC in B 407 or EC 135.
Buen vuelo
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AS350 info wanted pls
Hi all,
Can anyone clarify the system used to record cycles operating the AS350.
I can understand 1 start--shutdown = 1 cycle...............but have been told a percentage of a cycle is recorded each time during a landing when N1 reduces below ???%
Can't remember the figures.....................anyone?
Cheers
Bn
Can anyone clarify the system used to record cycles operating the AS350.
I can understand 1 start--shutdown = 1 cycle...............but have been told a percentage of a cycle is recorded each time during a landing when N1 reduces below ???%
Can't remember the figures.....................anyone?
Cheers
Bn
"Just a pilot"
Without cycle count sheet or RFM handy, I hope the following is helpful-
A normal NG cycle is one start and warmup, takeoff, and 30 sec ground idle cooldown. IN that instance, your cycles would be determined by your maximum NG, a K1 value.
In the real world, you may have many power changes with various high power settings, the highest of which would determine your K1.
You could also have low power settings between starts, so you add a cumulative K2 to the max K1.
Example- I start and takeoff, normal power on approach and cooldown- max Ng 96%, cycles logged 0.6.
Alternate, 1 start and takeoff 96% Ng, K1 0.6, log 0.6 cycles
HOGE power check, max NG 97%, new K1 0.7 log 0.7 cycles
Agressive approach, min NG 85% adjust cycles with a K2 of 0.1, terminate at hover without exceeding previous high NG. No change K1, cycle calculation K1 0.7 + K2 0.1 log 0.8 cycles.
I land from hover and roll back to ground idle, adding a K2 of 0.15 to previous 0.1, total K2 0.25. If I shutdown, cycles would be K1 0.7 + K2 0.25, log 0.95 cycles.
NO engine shutdown, max power departure 100% Ng yields a K1 of 1.0. Then sobered by previous hairy approac, I make a normal power on approach (without exceeding previous high NG) to hover, land and cooldown. Cycles K1 of 1.0 and sum of K2 0.25, Log 1.25 cycles.
Not as complicated as it sounds. Max NG between starts equals K1, add sum of K2 events yields cycles to log.
A normal NG cycle is one start and warmup, takeoff, and 30 sec ground idle cooldown. IN that instance, your cycles would be determined by your maximum NG, a K1 value.
In the real world, you may have many power changes with various high power settings, the highest of which would determine your K1.
You could also have low power settings between starts, so you add a cumulative K2 to the max K1.
Example- I start and takeoff, normal power on approach and cooldown- max Ng 96%, cycles logged 0.6.
Alternate, 1 start and takeoff 96% Ng, K1 0.6, log 0.6 cycles
HOGE power check, max NG 97%, new K1 0.7 log 0.7 cycles
Agressive approach, min NG 85% adjust cycles with a K2 of 0.1, terminate at hover without exceeding previous high NG. No change K1, cycle calculation K1 0.7 + K2 0.1 log 0.8 cycles.
I land from hover and roll back to ground idle, adding a K2 of 0.15 to previous 0.1, total K2 0.25. If I shutdown, cycles would be K1 0.7 + K2 0.25, log 0.95 cycles.
NO engine shutdown, max power departure 100% Ng yields a K1 of 1.0. Then sobered by previous hairy approac, I make a normal power on approach (without exceeding previous high NG) to hover, land and cooldown. Cycles K1 of 1.0 and sum of K2 0.25, Log 1.25 cycles.
Not as complicated as it sounds. Max NG between starts equals K1, add sum of K2 events yields cycles to log.
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AS350 Info
After just starting to operate an AS350 along side our Bell 412 I know what you are going through .
I made up this sheet for our pilots to help work through the calculation of NG cycles. This will have to be read in conjunction with the table of Max. and Min. NG found in the Maintenance Manual (Arriel).
Hope it helps
Arriel 1B Cycle Counting:
(I) REFERENCE CYCLE (Ng): Theoretical cycle used a reference for setting service life limits. Includes one start, one power acceleration corresponding to the "takeoff power" and one shutdown.
(ii) OPERATING CYCLES: A flight may consist of two types of cycles:
- Complete Cycle: An engine operating sequence including one start, one power acceleration and one shutdown.
- Partial Cycle: An engine operating sequence corresponding to a power decrease followed by a significant increase without engine shutdown. It may be defined as the number of hover events and landings.
(iii) Free Turbine: All components. One flight = One cycle
Gas Generator Equation: N = K1 + (n x K2)
K1 = Coefficient corresponding to maximum Ng (see table over page)
K2 = Coefficient corresponding to minimum Ng (see table over page)
n = Number of partial cycles carried out between start and shutdown
I made up this sheet for our pilots to help work through the calculation of NG cycles. This will have to be read in conjunction with the table of Max. and Min. NG found in the Maintenance Manual (Arriel).
Hope it helps
Arriel 1B Cycle Counting:
(I) REFERENCE CYCLE (Ng): Theoretical cycle used a reference for setting service life limits. Includes one start, one power acceleration corresponding to the "takeoff power" and one shutdown.
(ii) OPERATING CYCLES: A flight may consist of two types of cycles:
- Complete Cycle: An engine operating sequence including one start, one power acceleration and one shutdown.
- Partial Cycle: An engine operating sequence corresponding to a power decrease followed by a significant increase without engine shutdown. It may be defined as the number of hover events and landings.
(iii) Free Turbine: All components. One flight = One cycle
Gas Generator Equation: N = K1 + (n x K2)
K1 = Coefficient corresponding to maximum Ng (see table over page)
K2 = Coefficient corresponding to minimum Ng (see table over page)
n = Number of partial cycles carried out between start and shutdown
Absolutely impractical, is it not.
You'd think in this day and age of dirt cheap computers someone would be able to design a $20 box that would record it all for you, eh?
You'd think in this day and age of dirt cheap computers someone would be able to design a $20 box that would record it all for you, eh?
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beetlenut,
We use max NG pulled during the flight + min NG used(only 85% or below)x the amount of times you droped the collective below 85% inflight for NG cycles.
NG95=0.6,NG96=0.65,NG97=0.7
NG81-85=0.05
I can't remember the rest of the figures, but you can find them in the Turbomeca Manuals.
As for NF cycles, 1 startup +1Flight +1Shut down= 1cycle
We use max NG pulled during the flight + min NG used(only 85% or below)x the amount of times you droped the collective below 85% inflight for NG cycles.
NG95=0.6,NG96=0.65,NG97=0.7
NG81-85=0.05
I can't remember the rest of the figures, but you can find them in the Turbomeca Manuals.
As for NF cycles, 1 startup +1Flight +1Shut down= 1cycle
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If your boss has enough coins in the bank you can buy a cycle counter that works it all out for you but it is pretty straight forward to record the cycles after a while when you get your head around it.
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Thanks to all respondents, think these comments sum it all up
Especially on a up/down/up/down survey trip the number of landings gets a bit blurred.
Cheers BN
Absolutely impractical, is it not.
Quite agree - I've got better things to do than count how many times I've w*nked the handle
Cheers BN