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By TopCat
#1858240
Another thing I've read about but never tried, is flying with the throttle wide open, and the mixture very lean - so far lean of peak that there's no danger of melting the cylinder heads because there's so little fuel burning.

It's not on my list of things to try out, but I guess controlling power with mixture is at least possible.

I still think one should simply be sufficiently current with glide approaches for it not to be difficult to glide from the overhead. Or from early downwind or even crosswind if there's that much speed on - just pull the mixture at an appropriate place. Ok you'll have to slow down but would it really be that hard?

Shame on anyone that can't reliably glide to the runway from abeam the downwind numbers in something that doesn't glide like a brick.
By TopCat
#1858374
riverrock wrote:Can you end up over-boosted with detonation with an overly lean mixture and full throttle?

No idea. That one's well above my pay grade. As I said, I've no intention of trying it except in an emergency situation.

Is it not the case that over-boosting can only be achieved with turbo- or super-chargers?

Even with a wide open throttle, the maximum inlet pressure can't be more than 1 atmosphere surely?

Happy to be educated by someone that knows a lot more about engines than I do.
#1858390
Rob L wrote:Last resort in the case of throttle cable and mixture cable failure is to switch the mags off. The exhaust will probably depart the aircraft


Surely only if you switched the mags back on again?

The old Monosoupape rotary engines used to use ignition control to control the power.

https://en.wikipedia.org/wiki/Gnome_Monosoupape#Control

riverrock wrote:Can you end up over-boosted with detonation with an overly lean mixture and full throttle?


You can cook the cylinders and exhaust valves. but not with an "overly" lean mixture, but with it leaned to around the stoichiometric ratio (which should be peak EGT-ish). Lean further and the temperatures come down again.
By riverrock
#1858406
Detonation is more likely to happen with high cylinder pressure (high pressure as full throttle / high MAP in injected engine), high heat (you're already running full throttle so there is heat around, and air removes less heat than excess fuel), longer combustion time (leaner mixture - the extra nitrogen from air slows combustion) and if it does happen, it will increase heat significantly itself.

So there is a risk - but as @Paul_Sengupta says - if you go extremely lean, there shouldn't be enough fuel to burn to maintain that heat increase so detonation risk should be mitigated (essentially the same reason that detonation isn't an issue at low power settings normally, so you can lean as much as you want when taxiing to keep your plugs clean). Engine wont sound healthy, as the induction system on pretty much all GA engines doesn't provide a perfect balance across cylinders, so you'll get different mixes and so rough running.
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By StratoTramp
#1870531
I've left mine on when training before. It was because another pilot came up to chat to me whilst I was walking round the plane...

Obviously I should have just restarted the walk round. But I thought in future when it looks like a pilot is doing his walk around I'd make an effort to be deliberately anti-social and not talk to him till he looks like he has finished :lol:

Luckily I caught it when I was going round the box and checking the ailerons before power check. Though I imagine it would be quite easy to miss as your focus is checking the ailerons go up and down!

Now as part of my aileron/box check I take a deliberate look at the pitot tube condition.

The instructor said he noticed it but was waiting to see if I would, he was going to tell me at power check.

I suppose an additional check would be to have one last look at it as you do one last glance over the instruments & readings before takeoff.

Eventually end up doing more checking than flying.
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By Rob P
#1870539
StratoTramp wrote:
I suppose an additional check would be to have one last look at it as you do one last glance over the instruments & readings before takeoff.


Not easy for we low-wing types.

Rob P
Last edited by Rob P on Fri Sep 17, 2021 3:35 pm, edited 1 time in total.
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By StratoTramp
#1870540
:lol: Low wing what's that...? just kidding.

Fair enough. I'd go with anyone interrupts the walk round restart then, or maybe make a beeline for the pitot. :lol: I've left the door open before (again realised before takeoff...) and also switched the fuel off rather than on at start-up (it had been left in the 'on' position, so I toggled it off). I realised this when the engine died after 8 seconds :roll: :lol: no harm really but mega dumb as i know the on and off positions i just toggled the switch whilst on "autopilot"!
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By Flyin'Dutch'
#1870541
TopCat wrote:So what is the correct technique for landing with engine control with the throttle stuck open?


Set yourself up so you can make a glide approach and then pull the mixture.

That way you will have the option to go around should things go really bad, but like to think that with my gliding back ground I may well pull it off without too much bother.
By TopCat
#1870547
Flyin'Dutch' wrote:
TopCat wrote:So what is the correct technique for landing with engine control with the throttle stuck open?


Set yourself up so you can make a glide approach and then pull the mixture.

That way you will have the option to go around should things go really bad, but like to think that with my gliding back ground I may well pull it off without too much bother.

Of course, as I said earlier:

TopCat wrote:
Rob L wrote:and few understand how to control a safe landing with a throttle stuck on full. Not that this happens very often; it's a learning exercise :)

Fly to the overhead and pull the mixture. Perfectly straightforward.

Was this not what you had in mind? :wink:

Joking apart, I'd be interested to know the technique. Is it mags or mixture?


But @Rob L was suggesting something else, I thought?
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By leiafee
#1870555
Rob P wrote:I had an E-Type that if you accelerated hard trapped the throttle slide against the spaceframe, fully open.
That was exciting until you flicked the ignition off. :shock:


I’ve had a fuel clip trap the X’Air throttle lever both part open and part closed at various times. Always managed to free it but very attention getting.
viewtopic.php?f=13&t=90656&p=1299682
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By PeteSpencer
#1870725
Final walk around before getting in : one of the most important checks of all: confirms:

Towbar stowed
Pitot cover stowed
Fuel drains not leaking -no big black drips on tyres
Shocks equal
Baggage door closed
Cowling Dzus fasteners horizontal
Fuel caps flat /secure / not rotated
No tie downs attached
No loose tie-downs with metal
fixings lying in the grass ready to fly up into the prop
(On hard parking) no FoD in front of prop

Never miss it. :wink:
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By Cessna571
#1870886
I was taught to always check the cowling clips, then stand about 10 feet away in front of the aircraft for about 10 seconds, point at the fuel caps, pitot, tiedown points, etc before I get in.

Bit of a gross error check, before we fly.
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By Rob P
#1870957
Historically I always started an A Check at the spinner (except on twins obviously)

For the last few years I have started with the pitot cover, then to the spinner.

The cover, with its "Remove" banner has a place it lives in flight, very visible when climbing in.

Now if I can just crack replacing the cover before tying down the canopy cover as I leave the hangar I'll be well chuffed.

Rob P
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By PeteSpencer
#1870978
‘S funny how these little strategies develop :

Our a/c has been taken off twice with the towbar attached ( neither time by me) the second time resulting in a nose gear up landing requiring an engine tear down .and a £34k insurance claim .

The towbar doesn’t leave my hand for one second until the a/c has been pulled out of the hangar into position for start-up . The towbar is then detached and stowed immediately in the baggage compartment and the baggage door left pinned wide open till the end of the final walk round when towbar stowage is double checked and baggage door locked.

The pitot cover comes off at same time as L wheel chock is removed and the rubber cover goes into my shirt breast pocket with the entire ‘remove before….’ banner streaming clearly in view .

Then when I climb in, the rubber bit is poked onto the red gust lock blade which is stowed in pax footwell pocket with red ‘remove before’ streamer hanging over the edge of the pocket.

So before departure a glance at R footwell pocket immediately shows pitot cover and gust lock stowed, :wink:
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