Bell 206: JetRanger and LongRanger

[rotornut]

Ok, thanks for that, remote. I've only experienced helicopter flying in the east where you never see low skids on a 206.

[206 jock]

Hmmmm...smoking 206

My 206 has just come back online, after annual, T/T straps, battery etc etc..

Oh yeah, and new #2 turbine wheel, P/T and G/P supports, explosion ring A/D...so now I'm very poor.

The thing is: it's done 9.4 hours since and it's smoking a bit too much for my liking. After shutdown, there are wisps of blue smoke coming out of the exhausts. More worryingly, yesterday - after the third start of the day - ground observers at my office rang me to say that after first wind-up to 100%, there was a fog of blueish smoke hanging round the back of the cabin.

I've had some 'advice', which varies from don't fly it until they've taken the turbine out again (please lord ...no!) to leave it a few more hours to see if the carbon builds up the labyrinth seals better.

BTW in flight all T's and P's are fine - if anything, temps are down on how it was previously.

Any thoughts?

[Hughes500]

Without a doubt it is the carbon seal. When this goes it dumps oil in the collector which turns to smoke after shut down ! Looks like you are unlucky as the work you have had done on the turbine would be nowhere near the carbon seal. From memory last one I had go cost about £ 1500 to sort

[rotaryman]

Sounds like the Bellows seal to me...

or is the carbon seal and bellows seal one and the same?

[diethelm]

After a rebuild, while running the engine on a test cell, one of the things they look for is smoke on shut down. There is a simple adjustment of which I forget what it is that will allow this to go away. If it is the carbon seal, it was out when they either re-worked or exchanged your GP and PT support. I would think this would be under the warranty from your engine shop. Call the field support poeople from whichever AMC did your engine work.

[206 jock]

The shop who did the work (thank goodness I didn't send it to the USA) are saying that it looks like the no5 seal (I'm guessing that's the same as the carbon/bellows seal). My maintenance outfit also warned me about a little oil seepage from the bottom of the collector, but did say it 'should' cure itself after a few hours.

Thanks for the feedback.

Received wisdom is run it for 5 more hours: if it's still smoking, out comes the turbine. Woud you, if it were your machine? At the mo, oil level loss is negligible.

Bleedin' helicopters

[rotaryman]

I have had it happen were you couldn't see the Helicopter for the Smoke!!

Firies in attendance etc..LOL My advise is Keep a close eye on your Oil levels while it settles down..Or gets worse.

[Rusty Bifilar]

Have a look at the power turbine oil check valve first.

[Moet04]

Have had the same on a B206 Turbine after wheels work. It ended up being an incorrect pressure differential either side of the labyrinth seal and was re ctified by changing a screw on the top of the turbine. The screw had a hole running through it and the size of hole can be adjusted!! TRY THIS!!

GOOD LUCK

[Steve76]

If you were working this machine in the field, would it be overhauled for this again?
= NO
The oil burn is probably so miniscule that it would be far cheaper to top up the oil than pay the repair bill.
Just drive it for another 100hrs and then consider if it bothers you enough or whether the oil consumption warrants it. You might find it settles down after a time to a constant oil consumption or diminishes completely.

A couple of points that you can start to apply to remedy this in the future.

1) do a 3 minute cooldown instead of the suggested 2 minutes.
2) after shutdown (obviously) before tying the rotor system down, run it backwards for a couple of revolutions.

[Hughes500]

Steve 76

If you are using Mobil254 dont need to turn the rotor backwards ! You must be using old technology oils !

[CYHeli]

Mobil 254???

Does this wonder oil work on other helicopters powered by Allison? Eg. the H500 and therefore remove the need to 'wind-back' the blades to remove carbon build up?

[that chinese fella]

Steve 76,

I have seen a graph showing the Turbine 'soak' temperature-v-time and the temperature has fairly well stabilized after 1:45 minutes (from memory) and remains linear after this point in time. I guess this is where Bell round out the cool down time to 2:00 minutes. From this graph it would appear any additional idle time is not warranted.

I will attempt to chase the graph down for all to see.

Cheers

TCF

[vaqueroaero]

For the C20 B/J Rolls Royce recommends using MIL-L-23699 oils, such as Mobile Jet 254 or Aeroshell 560 in the engine. These have much better anti-coking qualities and better lubrication at higher temperatures

For the gearboxes Bell recommends using DOD-L-85734 (Triple Nickel) oils. Much better penetrating qualities. It does not do so well in the engine where it can lead to coking. Long term use may also lead to seal leakage in the accessory gearbox.

What it boils down to though is how many types of oil do you want to use in the aircraft? Both types are approved for use in the engine and gearboxes.

As for the 2 minute cool down - that's to allow the 6/7th bearing to cool as much as possible and to drain the oil out of it to prevent coking.

[bellsux]

Oils aint oils Sol... Jet Oil II is made to MIL-PRF(L)-23699F-STD and has been in use for years but it can suffer from coking so others have used Mobil 254 which is MIL-PRF(L)-23699F-HTS, a third generation synthetic oil. Basicly the same stuff but with the newer additives they changed the spec to HTS, High Thermal Stability so hopefully no coking. 254 is more expensive and can cause slight seal leakage in transmission gearboxes so for that reason I prefer to use Jet Oil II in them. Also if you have any misting of 254 oil from the engine it will peel any danger or rego stickers off the tail boom (reacts with the glue) over time.

Now I have a preference for the BP products I think that the 2380 turbo oil is far superior to Jet Oil II and they also have the 2197 turbo oil which is MIL-PRF-23699F-HTS standard (same as 254) but haven't used that as the 2380 does the same trick but cheaper than 254.

[trackdirect]

206 L RANGE EXTENDER

I am trying to track down a range extender for a 206L, They are a bit hard to come by these days, anyone have one in the shed spare that they want to sell??

Thanks

TRACKDIRECT

[206 jock]

Looks like it was the no5 seal. Turbine came out again last Friday, overnighted to shop, seal replaced Monday, turbine refitted Tuesday, flying again today. No smoke or anythign untoward.

And best of all, done under warranty, even though the shop had to replace the seal (cheap) and the fitting (not so cheap) to guarantee the repair.

So if anyone needs an RR250 turbine shop, these guys are first class. Anyone who sticks by their product is worth supporting in my books

[Hughes500]

206 Jock, nice to hear Arrow Aviation looked after you well. They have done lots of work for me and have always been first class. Which is more than you can say for some AMC's - no names no pack drill

[KikoLobo]

206B L.E.D pos lights.

Looking for a kit to change my nav lights to LED lights on the Bell 206b....
(Anti col would be great too)

Any clues on where to find it???

[bellsux]

www.whelen.com