Garret envy?

[Neville Nobody]

What is the standard proceedure for fuel condition lever in PT6 twins when taxing? Being a learner at this sort of thing I would have thought it would be better to taxi in low or ground idle? Twins I've seen taxing recently have been making a lot of noise and it seems to me they were in flight idle. Is there a reason for this? Is it Garret envy and trying to make as much noise as possible? Is it the need to taxi with your feet high up on the footrests and so needing lot of power just to move?

[ebby1028]

Hey Neville, get a clue. Don't make yourself look foolish on here with stupid questions. Do some research first, it's not hard. If a 331 or PT6 is not loud.....you should probably feather it.

[717tech]

Anyway... Kingair 200 we taxy around in low idle.

[Towering Q]

Yes Neville....there will be no light-heartedness or poor attempts at humour on these pages....what were you thinking?:rolleyes:

[blackhand]

I would surmise that the egines were at high idle, low idle being the other option.
Why, perhaps to run Aircon pump

[Neville Nobody]

Just wondering really, some are quiet and some seem to make a lot of noise. I have noticed lately the same machine a Kingair operating differently at the same airfield. Sometimes it just sneeks in no fuss, other times it arrives on the apron with great noise. As for appearing foolish, I can't help my looks, born like it I'm afraid.
Ebby and Fanta, some of us never stop learning as opposed to you pair that know everything. How do you pair operate your Kingair engines on the apron, low idle or high? :8

[Fantome]

being so terribly hard of hearing , as nearsighted as Magoo and apparently so humourless too , (the first from years being encased by RR Darts, ) the rough and tumble of this site is a feather's brush.

no sense no feeling they used to say. and when both hearing aids fly out
during a good blow of the old conk well . . . . hullo??


(If you want to hear the difference between PT6 operators just sit on the fence at Tyagarah sometime, or so i'm told, as the skydivers C208 comes and goes.
comboys and caressers , or so they say.)


and by the way there is still a lot to be said for decluttering as in wiping old posts and threads that contribute nil to human understanding.

except for those that are as funny as a hatful. eg the bloke who posted saying that the DH
Rapid had somehow lost an 'e' and the other bloke who came in with - no mate he didn't lose it. he put it in hanger.

[Josh Cox]

Usually Low Idle.

At times when you have a combination of high ambient temperature, high density altitude and/or high accessory drive loads, high idle may be needed to ensure the max idle ITT is not exceeded.

One aircraft I've had a problem with was the C208 (-114A ), on the ground at Meekatharra on a forty something degree day, at idle the idle ITT was exceeded.

Apparently the B200 with the -41 often has a similar issue.

I turned off the Aircon ( reduced accessory load ), went to high idle and then turned the Aircon back on, worked a treat.

[OZBUSDRIVER]

There is a difference in prop noise in PT6s whether three or four or five blade props. B200s especially appear noisier to me in the later models running 4 blade props. The engine noise itself appears pretty well mute compared to a Garret which sounds like a grinder full of marbles.

[psycho joe]

Beta control defines the range of operation in which residual idle thrust can be controlled by reducing blade angle.

[AerobaticArcher]

I always found the C208 was better to taxi around with the condition lever somewhere between low and high idle (around 60% Ng). This meant you could taxi the aircraft without the need to accelerate the engine, causing spikes in ITT. All we did was pull back into beta to take away the thrust.
When running the aircon, the C208 manual says to go to high idle so you don't exceed 685 deg C (the low idle ITT limit).

On the Kingair, was a similiar situation, idled a bit higher so it would roll, then used beta to control speed, used high idle in hot conditions, so idle ITT was not exceeded.

But at the end of the day, it comes down to the operator

[Howard Hughes]

I have Garrett envy, even if I were to taxi around with condition levers at high idle and the power levers fully open, I still wouldn't make as much noise as a Garrett!!;)

[Grogmonster]

Neville,

As suggested above re the B200 I would say high idle for aircon but the reason that it is sometimes noisier than normal is when a pilot inadvertantly leaves power levers in beta, flat pitch, therefore no prop drag and higher RPM resulting in higher tip speed. Good drivers tend to use Beta rather then riding the brakes thus avoiding expenive brake pack replacements. Also I have noticed that the new B250 getting around SE Qld seems to be noisier, on ground at high idle, than the average aircraft probably due to its new fangled composite props.

Groggy

[morno]

On the PC-12 (-67B), in hot conditions, you needed to run the engine at high idle just to keep the ITT down for idle.

On the B200, running around 65% (70-71.5% is normal high idle, 61% I think it is for low idle), is enough to keep the ITT temps down and also enough to run the air conditioner.

A B200 with 4 bladed props running around in beta, is a noisy bugger, but it saves the brakes!

morno

[OpsNormal]

....compared to a Garret which sounds like a grinder full of marbles...

Oh, that's where I left them.... Sorry....:\

Cannot remember specifics but the four bladed -41 equipped B200 I used to pole around many moons ago used to need the condition levers up a little bit, especially in the height of summer/wet season with the aircon running. Certainly made the freon compressor work more effectively at the higher drive speed on the ground.

Morno, I'll see your "noise" and raise you mine... :E

Regards,

OpsN.;)