EC120
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This is an excerpt from the AAIB Bulletin that Nr Fairy mentioned.
Gazelle yaw characteristics
In the majority of civil and military cases, loss of yaw control occurred in the hover or at low forward speed in light winds from the right. A few occurred in stronger winds or with wind from the left.
Both inexperienced and highly experienced pilots were involved in the military accidents and loss of control of pitch and roll during the subsequent high rates of rotation was a commonfeature. An 'optimised fenestron' was fitted to military Gazelles in the early 1980s as part of a weight upgrade programme.
The optimised fenestron had revised duct and hub fairings but did not appear to improve the incidence of sudden loss of yaw control.
The sudden loss of yaw control was attributed to 'fenestron stall'and, in response to concern, the Ministry of Defence (MOD) sponsoreda trial by the manufacturer, Eurocopter France, to investigate the phenomenum.
The trial took place in 1992/93 and demonstrated that, in conditions of low natural wind, a relatively small left pedal input of 5% (of total pedal travel) from the hover position can result in a yaw rate of 150°/sec being achieved in 10seconds.
It also showed that high yaw rates to the left (165°/sec)can be rapidly arrested by application of full right pedal without any tendency for aerodynamic stall of the fenestron.
The MOD advice included a statement that the extremely rapid build up of yaw rate in these circumstances was exacerbated if the SASwas not engaged.
The MOD trial did not establish why a small pedal input can result in the rapid build up of very high yaw rates. However, an earlier study, in 1991, by Westland Helicopters Limited had suggested that the trigger mechanism might involve a coupling of fenestron rotor induced swirl with the circulation contained in the main rotor tip vortices which may become aligned with the fenestron in certain flight conditions.
The study also suggested that considerationshould be given to changing the direction of rotation of the fenestron to become top-blade-aft which would probably solve the interactional aerodynamic problem.
Subsequent fenestron-equipped helicopters such as the SA365 Dauphin, EC135 and EC120 have top-blade-aft fenestron rotation; they are not known to suffer from sudden lossof yaw control.
In the majority of civil and military cases, loss of yaw control occurred in the hover or at low forward speed in light winds from the right. A few occurred in stronger winds or with wind from the left.
Both inexperienced and highly experienced pilots were involved in the military accidents and loss of control of pitch and roll during the subsequent high rates of rotation was a commonfeature. An 'optimised fenestron' was fitted to military Gazelles in the early 1980s as part of a weight upgrade programme.
The optimised fenestron had revised duct and hub fairings but did not appear to improve the incidence of sudden loss of yaw control.
The sudden loss of yaw control was attributed to 'fenestron stall'and, in response to concern, the Ministry of Defence (MOD) sponsoreda trial by the manufacturer, Eurocopter France, to investigate the phenomenum.
The trial took place in 1992/93 and demonstrated that, in conditions of low natural wind, a relatively small left pedal input of 5% (of total pedal travel) from the hover position can result in a yaw rate of 150°/sec being achieved in 10seconds.
It also showed that high yaw rates to the left (165°/sec)can be rapidly arrested by application of full right pedal without any tendency for aerodynamic stall of the fenestron.
The MOD advice included a statement that the extremely rapid build up of yaw rate in these circumstances was exacerbated if the SASwas not engaged.
The MOD trial did not establish why a small pedal input can result in the rapid build up of very high yaw rates. However, an earlier study, in 1991, by Westland Helicopters Limited had suggested that the trigger mechanism might involve a coupling of fenestron rotor induced swirl with the circulation contained in the main rotor tip vortices which may become aligned with the fenestron in certain flight conditions.
The study also suggested that considerationshould be given to changing the direction of rotation of the fenestron to become top-blade-aft which would probably solve the interactional aerodynamic problem.
Subsequent fenestron-equipped helicopters such as the SA365 Dauphin, EC135 and EC120 have top-blade-aft fenestron rotation; they are not known to suffer from sudden lossof yaw control.
Join Date: Jul 2004
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SPEED ec 120? 407? astar 350bIII
i would like to know with a full tank of gas and 700 lbs for people
(3.5 people) how fast will these go
ec 120 is published at 127 knots
it that true or exaggeated?
also same situation for the 407 and as 350 bII and BIII
full fuel and 700 off people
how fast will thay cruse?
the jetranger your lucky to get 105 kts
thanks
(3.5 people) how fast will these go
ec 120 is published at 127 knots
it that true or exaggeated?
also same situation for the 407 and as 350 bII and BIII
full fuel and 700 off people
how fast will thay cruse?
the jetranger your lucky to get 105 kts
thanks
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ec120 is about 120kts, unless its a dud one(lots of them around) then its more like 110kts
as350b2 is 125/130kts,
cant help you with the 407 or b3 , wish i could , all the power you could ever wish for!
as350b2 is 125/130kts,
cant help you with the 407 or b3 , wish i could , all the power you could ever wish for!
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Gotto agree with whatsarunway,
the 120 is around 120kts and the B2 differs depending on temp and alt.
We're at sea level and 25degC and the B2 does around 122kts when fully loaded.
the 120 is around 120kts and the B2 differs depending on temp and alt.
We're at sea level and 25degC and the B2 does around 122kts when fully loaded.
Join Date: Jun 2002
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Never been in an 120. The B2 with a full bag , and a hot day, 120 is pushing it , espically if you have floats or a bubble window, Lucky to get 105 then. B3 , mayby a little faster, same thing with the floats. Just performs a lot better at alt.
the 407 is quicker......
How about looking at an A119, fast, powerfull, plays up high very well, lots of room in the back.
RB
the 407 is quicker......
How about looking at an A119, fast, powerfull, plays up high very well, lots of room in the back.
RB
EC120:
empty 1036 kg
pax 320 kg
fuel 320 kg
= 1676 kg, max Gross = 1715 kg ->98% loaded
got 105 to 110 kts out of it, need LONG rungway, running take off
407
empty 1335 kg
fuel 446 kg
pax 320 kg
= 2101 kg, max Gross = 2268 kg -> 93% loaded
getting 125 kts, enough power to go straight up!
empty 1036 kg
pax 320 kg
fuel 320 kg
= 1676 kg, max Gross = 1715 kg ->98% loaded
got 105 to 110 kts out of it, need LONG rungway, running take off
407
empty 1335 kg
fuel 446 kg
pax 320 kg
= 2101 kg, max Gross = 2268 kg -> 93% loaded
getting 125 kts, enough power to go straight up!
Last edited by GoodGrief; 13th Jul 2004 at 02:04.
Join Date: Jan 2001
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GoodGrief, one can go to 5250 lbs (2381 KG) with ease, just have the applicable FMS onboard.
A standard fuel load is 860 lb (390 KG) or 2.0 hrs, so I assume you have aux tanks?
I always fly with a large ski basket and get approx 125 kts, see the pics of C-FALM below. We'd expect a bit more speed than that when flying a clean aircraft.
All this power and speed, plus an initial rate of climb at or near 2,000 fpm (@55kts, and depending on alt and temp)
A standard fuel load is 860 lb (390 KG) or 2.0 hrs, so I assume you have aux tanks?
I always fly with a large ski basket and get approx 125 kts, see the pics of C-FALM below. We'd expect a bit more speed than that when flying a clean aircraft.
All this power and speed, plus an initial rate of climb at or near 2,000 fpm (@55kts, and depending on alt and temp)
Last edited by 407 Driver; 13th Jul 2004 at 03:24.
Here are today´s results:
empty 1337 kg
pax 300 kg
fuel 408kg
= 2045 kg
cruising between 1000 & 2000 ft MSL, QNH 1014 to 1016, oat 15 to 18° C
TQ 88%, TOT 705
gives speed 130 to 132 kts.
fuel burn = 363 pounds/h.
Yes, we drive the aux tank.pretty much mandatory in Germany because of high landing fees (up to €80 per landing ).
empty 1337 kg
pax 300 kg
fuel 408kg
= 2045 kg
cruising between 1000 & 2000 ft MSL, QNH 1014 to 1016, oat 15 to 18° C
TQ 88%, TOT 705
gives speed 130 to 132 kts.
fuel burn = 363 pounds/h.
Yes, we drive the aux tank.pretty much mandatory in Germany because of high landing fees (up to €80 per landing ).
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Pull that up to 94Q and/or 724 MGT and you'd be close to the 140 Kt Vne ! Is your fuel flow on a guage or estimated? I generally figure on 330 PPH, although we usually are cruising at 8000 to 10,000 ft.
Hi!
363 pph is read from gage and confirmed by refueling.
we don´t really like driving the engine at max tq (93.5) or too hot.
how much do you pay for fuel ?
do you mind the vne chart at altitude ?
cheers
363 pph is read from gage and confirmed by refueling.
we don´t really like driving the engine at max tq (93.5) or too hot.
how much do you pay for fuel ?
do you mind the vne chart at altitude ?
cheers
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At 10,000' +10C Vne = 121 kts, but the GPS speed may equate to 130 Kts + depending on the wind.
We have a major fuel contract, I can't divulge the price, but when you buy over 4,000,000 Litres yearly, the pricing is quite attractive.
We have a major fuel contract, I can't divulge the price, but when you buy over 4,000,000 Litres yearly, the pricing is quite attractive.
Join Date: Jul 2002
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Hot EC120/Arrius
Hi all,
let's see whether someone can help me out with a dilemma I am having with our EC120 - Arrius powered.
Since a short while I get a lot of temperature on the engine - T4.
Until recently the limitations where I fly (hot and humid) would come on as follows:
First Ng, second Torque, T4 would never get yellow as I would have to pull Ng past redline for that.
T4 goes yellow at 830ºC, normal max cruise would see never more than 780ºC.
Lately T4 is the primary limit, sometimes runnig out of yellow/red line befoe Ng gets close to yellow (at about 99.7 %).
So T4 runs anywhere from 35ºC at ground idle to 55ºC at max cruise OVER the regular temp at these levels.
The weird thing is, it does this at unregular intervalls.
I can tell right at start up when it will be running hot - ground idle would hover around 610ºC instead 565ºC.
Sometimes I would have 4-5 periods running hot, the same with normal temps.
It never changes once started up.
It seems like something gets stuck open or not. To much fuel I guess. My mechanic is already on the fritz with this.
Can't get an answer from Turbomeca without having their guys show up, which is a fortune!
So if anyone can give me a hint or had the same/similar experience, please shoot!
Otherwise we have no choice, but bite the lemon and get Turbomeca here.....
Thanks,
3top,
let's see whether someone can help me out with a dilemma I am having with our EC120 - Arrius powered.
Since a short while I get a lot of temperature on the engine - T4.
Until recently the limitations where I fly (hot and humid) would come on as follows:
First Ng, second Torque, T4 would never get yellow as I would have to pull Ng past redline for that.
T4 goes yellow at 830ºC, normal max cruise would see never more than 780ºC.
Lately T4 is the primary limit, sometimes runnig out of yellow/red line befoe Ng gets close to yellow (at about 99.7 %).
So T4 runs anywhere from 35ºC at ground idle to 55ºC at max cruise OVER the regular temp at these levels.
The weird thing is, it does this at unregular intervalls.
I can tell right at start up when it will be running hot - ground idle would hover around 610ºC instead 565ºC.
Sometimes I would have 4-5 periods running hot, the same with normal temps.
It never changes once started up.
It seems like something gets stuck open or not. To much fuel I guess. My mechanic is already on the fritz with this.
Can't get an answer from Turbomeca without having their guys show up, which is a fortune!
So if anyone can give me a hint or had the same/similar experience, please shoot!
Otherwise we have no choice, but bite the lemon and get Turbomeca here.....
Thanks,
3top,
Join Date: Jul 2002
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Selfish,
with the broken thermocouple, did you have ANY temp indication?
Jellycopter,
yes, to the coastal area (Panama), and we wash the compressor all the time ( about every 10-15 hours, and especially when returning from a ocean trip or low coastal flying).
Besides this temp thing is not a gradual decay (like the compressor loosing efficiency) of temp margin, but it happens right at start-up.
It is NOT an overtemp on starting, everything under control.
But it feels to me there is some valve that gets stuck open (or not, when temps turn out to be fine), and T4 is higher than normal for the whole cycle. Sometimes it helps to shut down and restart, but if the T4 doesn't turn out "normal" after the 3rd time I would have to wait 1/2 hour for the next restart (according to POH). So normally, if I can get away with the higher temp without running red lines, I fly it.
I tell you, it is quite tricky to keep passengers cool!
3top
with the broken thermocouple, did you have ANY temp indication?
Jellycopter,
yes, to the coastal area (Panama), and we wash the compressor all the time ( about every 10-15 hours, and especially when returning from a ocean trip or low coastal flying).
Besides this temp thing is not a gradual decay (like the compressor loosing efficiency) of temp margin, but it happens right at start-up.
It is NOT an overtemp on starting, everything under control.
But it feels to me there is some valve that gets stuck open (or not, when temps turn out to be fine), and T4 is higher than normal for the whole cycle. Sometimes it helps to shut down and restart, but if the T4 doesn't turn out "normal" after the 3rd time I would have to wait 1/2 hour for the next restart (according to POH). So normally, if I can get away with the higher temp without running red lines, I fly it.
I tell you, it is quite tricky to keep passengers cool!
3top
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Jellycopter,
we hardly ever use P2. Too hot down here for that! But anyway I even tried it out in flight: T4 will hardly move in cruise -maybe some +5-10°C (if running hot or not doesn't matter, it will move about the same amount in either case). It will go down again when shut off, besides you really cannot miss the P2 indication on the screen.
Mr. Selfish,
I also believe if a thermo couple is out (or all of them) there shold be some indication about this or no T4 at all.
What you mean is the "Powercheck" and you get to it by scrolling down the screen:
first press, you change from FLI to 3 individual gauges
second press, you get the "Powercheck"
third press, you get the Weight&Balance screen
fourth press, back to FLI.
The Powercheck will indicate exactly what T4 does:
When T4 is normal I get a "good margin" (indicted by some negative T4 value)
If hot I get a "bad margin" (indicated, in my case, with some +35°C Margin)
Besides the software for thePowercheck is not that great yet.
We still get "bad torque margins", that's why Turbomeca came out with a correction table (paper
) for the torque values....
However the T4 marging is a good indicator.
You know, if the engine would go sour one could follow up, as this normally happens gradually (" I used to be able to get out of here with 4 people instead of 2, before hitting redline, etc."
My case is different:
If I start with T4 normal, I have all the power there is (not enough, by the way!! EC are you listening!!), and T4 never even gets close to yellow before I hit redline with Ng.
If T4 starts hot, I hardly ever get yellow on Ng before going red with T4!
Yesterday I had 2 flights normal and T4 at max cruise would read from 750°C to 775°C. Next 3 flights were hot with T4 at 825°C with torque around 76% and Ng around 98.2%!! (850° for take off!)
I really wonder!
Supposedly a Turbomeca certified mechanic is to show up today. I hope he finds the bug!
Nevertheless, PLEASE keep suggestions coming, anyone knows any good freelance mechanics (Arrius engine, turbomeca certified)?
3top
we hardly ever use P2. Too hot down here for that! But anyway I even tried it out in flight: T4 will hardly move in cruise -maybe some +5-10°C (if running hot or not doesn't matter, it will move about the same amount in either case). It will go down again when shut off, besides you really cannot miss the P2 indication on the screen.
Mr. Selfish,
I also believe if a thermo couple is out (or all of them) there shold be some indication about this or no T4 at all.
What you mean is the "Powercheck" and you get to it by scrolling down the screen:
first press, you change from FLI to 3 individual gauges
second press, you get the "Powercheck"
third press, you get the Weight&Balance screen
fourth press, back to FLI.
The Powercheck will indicate exactly what T4 does:
When T4 is normal I get a "good margin" (indicted by some negative T4 value)
If hot I get a "bad margin" (indicated, in my case, with some +35°C Margin)
Besides the software for thePowercheck is not that great yet.
We still get "bad torque margins", that's why Turbomeca came out with a correction table (paper
) for the torque values....However the T4 marging is a good indicator.
You know, if the engine would go sour one could follow up, as this normally happens gradually (" I used to be able to get out of here with 4 people instead of 2, before hitting redline, etc."
My case is different:
If I start with T4 normal, I have all the power there is (not enough, by the way!! EC are you listening!!), and T4 never even gets close to yellow before I hit redline with Ng.
If T4 starts hot, I hardly ever get yellow on Ng before going red with T4!
Yesterday I had 2 flights normal and T4 at max cruise would read from 750°C to 775°C. Next 3 flights were hot with T4 at 825°C with torque around 76% and Ng around 98.2%!! (850° for take off!)
I really wonder!
Supposedly a Turbomeca certified mechanic is to show up today. I hope he finds the bug!
Nevertheless, PLEASE keep suggestions coming, anyone knows any good freelance mechanics (Arrius engine, turbomeca certified)?
3top
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Arrius 2F
I would send a detailed account of your 'anomoly' to [email protected]
if he doesn't know what to do, he will know someone who does.
if he doesn't know what to do, he will know someone who does.
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Hi Frogspawn,
well I will give this man a try!
By now we had a tech from Turbomeca-Mexico here. We had all electric and electronic connections checked and cleaned - An anoying FLI failure went away, seems a dirty Torque sensor connection was the culprit.
Also found one badly worn thermocouple - promptly changed the whole harness:
GUESS WHAT: First 2 start-ups everything fine and perfect, ALL RIGHT!!
Started up today, BACK TO THE SILLY GAME!!
So I will write up that stuff and send it to the man you recommended!
Any more ideas out there?
3top,
well I will give this man a try!
By now we had a tech from Turbomeca-Mexico here. We had all electric and electronic connections checked and cleaned - An anoying FLI failure went away, seems a dirty Torque sensor connection was the culprit.
Also found one badly worn thermocouple - promptly changed the whole harness:
GUESS WHAT: First 2 start-ups everything fine and perfect, ALL RIGHT!!
Started up today, BACK TO THE SILLY GAME!!
So I will write up that stuff and send it to the man you recommended!
Any more ideas out there?
3top,