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Old 28th Jul 2004, 22:38
  #101 (permalink)  
 
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3top

Do you have sand filters installed ?
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Old 28th Jul 2004, 22:53
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Rotor Pilot,

no we don't have sandfilters. We hardly ever operate in sandy/dusty areas, besides the air-intake of the turbine on the EC120 is well hidden. The air has to go around a lot of sharp corners before getting to the intake.
Also if compressor deterioration was the problem it wouldn't show up intermediately - sometimes on sometimes off!

When the engine starts normal we have quite good numbers.
But you never know when she will run normal or hot (or at least indicate hot).

3top

Any Turbomeca guys lurking here?
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Old 29th Jul 2004, 06:58
  #103 (permalink)  
 
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3tops,

From I read above, it seems that you get this T4 reading difference all along the power on of your machine.
As far as I know, arrius 2F has a so called t4 conformation box in order to homogenized the temperature reading. The value is given to the VEMD by means of a couple of resistors, slope and 0 adjustement. Did you try to check this box or the resistors as it could be the source of this trouble ?

My 2 cts
Bunka
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Old 29th Jul 2004, 11:53
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maybe a daft question as not much experience of ec120 but i'll ask anyway. Can you spot any difference in Nr during startup between the two conditions?
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Old 29th Jul 2004, 20:38
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Downupside, Frogspawn:

I wrote the guy downunder and got a really quick reply!
Thanks god, there is no regional jealousy within Turbomeca (unlike EC!!), so he produced 4 more contacts to try! One of them is the Mexican technician from Turbomeca that was here.
According to our chief mechanic, him and the Turbomeca guy did all the confirmation box checks, but I am following up to confirm that. They also checked all other electronic or electric connections.
As mentioned a previous always present "FLI-failure" was finished off that way. (Dirty Torque sensor connection).

Erchie:

No I didn't notice any difference in idle Nr, but I didn't pay particular attention to that either, but generally there would not be a big difference.
BUT I will definitely pay closer attention to that now!
Any idea if "yes"?

3top
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Old 29th Jul 2004, 21:00
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Pardon my ignorance, but does the Arruis have a bleed valve on the compressor or a similar device?

I know that on several occasions with a Bell 206 Jetranger that I flew, a sticky bleed valve caused a high TOT at a low torque setting with a related low N1 reading.

The company I worked for had so many strange incidents with the EC 120's, eg blade strike after a downwind landing and the door flew completely open as there was no door strut attached.

Yep, in the full open position the door extends above the blades when rotating making for a spectacular noise and lots of u/s spares. The list goes on, but this is a complete new topic all on its own!

Good luck!
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Old 30th Jul 2004, 13:13
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Aviator,
that's a great design if it can do that! I will check this myself right away! I guess that door strut is good for something after all! Though they are loosing gas pressure rather quickly! Expensive to replace too.

Yes the Arrius does have a bleedvalve for the cabin heater, but it is closed at all times. If it is open there is a "P2" indication on the screen. However the T4 rise with P2 is only about 15°C max, not the 30-80°C I see!

Frogspawn,
your man from downunder came up with a similar case!
His was a intermittent failure in the T45 confirmation box.
I am just checking with him if this box checked okay with all the tests. If this is the case, I guess I have the culprit.
Ours checked fine with all the tests, so I am curious.

Keep you posted!

Anyone have some stories about the EC120B? Something we all could learn from?

3top
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Old 30th Jul 2004, 13:20
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Rotor Pilot,
no we don't have sandfilters. We hardly ever operate in sandy/dusty areas, besides the air-intake of the turbine on the EC120 is well hidden. The air has to go around a lot of sharp corners before getting to the intake.
Also if compressor deterioration was the problem it wouldn't show up intermediately - sometimes on sometimes off!
Thanks it was just a long shot.
I flew for a couple of years in areas where the dust and sand would cut the TBO's of the engines in HALF by transforming the compressor blades into grotesquely deformed razor blades. We were getting 500 / 600 hrs from each engine, tops.
So we had to install sand filters. After this we started having some variations in temps caused by the filters (if they were dry, or humid or wet or clogged they would affect the readings accordingly to their condition at any given time).

Can’t figure out anything else. Intermittent malfunctions are terrible even in computers let alone flying machines
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Old 12th Aug 2004, 09:40
  #109 (permalink)  
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EC120 - crank or fuel pump first ?

Starting EC120 when hot - crank for below 150 degrees, then put on fuel boost pump and wait 30 seconds OR fuel pump 30 seconds then crank then start ?

Manual seems to imply crank then fuel boost pump which works okay except that temp rises again while you wait for 30 seconds.

Can you do the fuel pump 30 seconds first and then crank and then start immediately without sending any fuel anywhere it shouldn't or otherwise doing damage (throttle closed of course) ?

How do you guys do it ?
 
Old 12th Aug 2004, 10:30
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Sure its not below 200?

the 120 only really needs the start pump if it hasnt been flown in a few days but what you do is crank, for about five seconds when the ng is getting to zero hit the pump wait for ten seconds and start!

always worke for me
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Old 12th Aug 2004, 12:26
  #111 (permalink)  
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You are right ! 200 degrees. Just checked manual. Good job not instructor rated on this one yet...

So, crank, 10 seconds fuel boost, start.

Will try this out.

Thanks !
 
Old 12th Aug 2004, 17:08
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might not be a bad idea to start with the throttle a bit further closed than the reccomened twenty whatever degrees and slowly open it after start.

and remember, the VEMD never lies!
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Old 12th Aug 2004, 18:06
  #113 (permalink)  
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Yep ! Not sure if this is just a hot and high mod for us in SA but we have the line drawn on the throttle well before you get to the indent originally used for starting. If you try to start more closed than this line, then there's no fuel going in anyway so no choice on the machine I fly.

Incidentally how soon do you open the throttle after the 'light up' as the machine I fly seems to hang about 300 degrees anyway ? What is normal, at what point can you say that all is normal and start to open up or must if be continuous from light up ?

Another 120 cooked this weekend apparently because once the voltage drops below 15 V you can't activate the release to close the throttle and noone is going to be that quick on the fuel shut off...
 
Old 13th Aug 2004, 07:32
  #114 (permalink)  
 
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when it starts to hang thats your cue to put in more juice,
we have that line here too and when the temp is not too hot, ie 220-260 we used to close the throttle further than the white line and when the temp got below the 200 open it slowly while starting, saves the battery from lov voltage during the start a bit,

like i say its not in the manual but it worked for us,
by the way make sure you do your W+B for every flight! not a bad idea to put the optional weight in the tail
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Old 14th Aug 2004, 03:09
  #115 (permalink)  
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The 120 is a simple machine, I have about 1500 hours in them and always start with the boost pump on, but watch the temp as we all know, if you are expecting a hot start a the throttle will need to be wound off ...perhaps alot....it is easy to go tooo far and shut it off.


Most normal starts I found requied a gentle increase to get the T4 to around 700 deg which is preffered on start, the secondry nozzels don't seem to accelerate it enough in some cases.

I would think twice about ballest in the machine, it ain't that bad. and the vmed info is as you probably know only in the flight manual section 7 if i recall. Best bet is to find some ground power and have a play.

Good luck
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Old 14th Aug 2004, 11:45
  #116 (permalink)  
 
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not that bad?

its the worlds worst when it comes to CofG. five people on bord is a no go wothout the weight in the tail and the battery relocated.
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Old 15th Aug 2004, 07:29
  #117 (permalink)  
goaround7
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Whatsarunaway seems to have a point. I was just doing W&B for a four pax flight and there's no way it's going to come back into the graph no matter how I plan the fuel.

Offered the clients the Squirrel instead.

Of course the EC would probably get off the ground, in the morning anyway, but then if something happens, you won't get pleasant treatment from Eurocopter or your insurers...

Anyone know of any incidents like this ? Is there an approved mod to relocate the battery and can you still get to it to disconnect it ?

However, did spend a few hours doing low level power line inspection in EC last week. Four hours at about 40 feet and 50 knots with three on board and she was very nice. Mucho impressed with manoeuvrability but looks like Squirrel and 407 for our charters.
 
Old 16th Aug 2004, 04:53
  #118 (permalink)  
oxi
 
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Yep...i agree, give me the 350 or 407 for the charters, i guess the 120 is like the 206.....built for 4 not 5.

But still a very good and user friendly machine.
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Old 17th Aug 2004, 08:38
  #119 (permalink)  
 
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Where is your battery goaround?

I have only seen it in the front end of the tail boom, acessed by the rear flap door.

You can put balance weights on the rear stinger too I think.
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Old 17th Aug 2004, 15:56
  #120 (permalink)  
goaround7
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battery is in (what I think is) the normal place - at the base of the tail.

Is there some kind of Eurocopter certified procedure for adding ballast in the tail or just a new M&B ?

Boss made up his mind to buy a Squirrel B or BA now anyway so hopefully will have options.
 


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