PPRuNe Forums - View Single Post - High accident rates in light twins an alternative?
Old 3rd Jun 2008, 00:11
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Pace
 
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>Easy, it won't. If it won't climb at Vyse, it won't cruise at any other speed. Simple<

Wizofox

I think I know what you are getting at! If you have max power on the remaining engine, Are holding blue line speed and have no climb then you will not be able to accelerate without loosing altitude. That I accept.

But lets take this further by using a different scenario. You decide to give up and make a forced landing. You shut down the good engine and become a glider to the nearest field.

You now control your speed with pitch. Ie you pitch for speed. You take whatever descent rate that gives to maintain your VREF and whatever profile.
(The 777 forced landing at Heathrow where they landed short both engines out) You now have only Kinetic or (potential energy) to power the aircraft.

Had you kept the other engine going you would have whatever power/energy that produced plus the Kinetic/or potential energy or Mickey Mouse energy or whatver you want to call it in pitching down.

Lets take an aircraft where the manufacturers claim no single engine climb at all ie no VYSE . ie the De havilland dragon rapide. Yet the aircraft will cruise level at single engine cruise if you loose it in the cruise. You say impossible as if it will not climb at VYSE it will not cruise level at any speed above that? So how come?

So we know that engine out like the 777 crash at Heathrow we have enough energy to maintain a VREF but we do not have enough energy to maintain level flight with one engine going if we can accelerate to single angine cruise by trading altitude for speed?

So in your books in that situation ie blue line and no climb at max power on the remaining engine. When you pitch for single engine cruise the speed will bleed back off to blue line?

But if at VYSE it even shows 50fpm you will be fine at a single engine cruise?

I can easely test this on my next twin flight. All I have to do is simulate an engine failure at say 2000 feet for safety (the plane does not know if its at 2000 feet or 500 feet) I then pitch for blue line and reduce the power until I get no climb or descent but maintain blue line.

No matter what I do with pitch looosing altitude in the process to get single engine cruise the aircraft will descend to the ground with that power setting selected?

Ok give me a couple of weeks and I will make a new thread here with the results include pitch angles, speeds, altitude lost etc as this is not what I see real world.

It is easy to google scientific calculations but there is something missing in those calculations as it is fact that light twins will cruise easely on one but will not climb easely on one.

I have shut down and feathered one engine for real on a few occasions at cruise but would not like to do that in the climb.

I for one am not happy with the explanations given here to what I have experienced for real and know to be true. This thread seems to be full of ego massaging and point scoring rather than a desire to get at the truth. I am happy to back down if I am wrong but as yet???

Pace

Last edited by Pace; 3rd Jun 2008 at 00:39.
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