Primarily for general aviation discussion, but other aviation topics are also welcome.
#1884809
When it happened to me, I needed to turn a tight 180 to land uphill and into wind. That meant stuffing the nose down hard to make sure I had enough airspeed to make the turn. All the feeling went to my toes as the rudder loaded up and the bank angle was steeper than any I was accustomed to. There is only one rule: Airspeed is life. Just have enough of the stuff.
#1884842
MichaelP wrote:....
The Motor Falke crowd could ‘pitch’ in since this motor glider often has a stoppable fixed pitch propeller.


From flying Motor Falkes (fixed pitch and feathering) and Self Sustainer equipped gliders I can confirm there is significantly more drag from a windmilling prop than a stopped one.

I've never tried it with a lycoming or similar but you might be surprised how much you have to slow up to get it a fixed pitch prop to stop.... I suspect doing so may use up quite a bit of height
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#1884862
ls8pilot wrote:
MichaelP wrote:....
The Motor Falke crowd could ‘pitch’ in since this motor glider often has a stoppable fixed pitch propeller.


From flying Motor Falkes (fixed pitch and feathering) and Self Sustainer equipped gliders I can confirm there is significantly more drag from a windmilling prop than a stopped one.

I've never tried it with a lycoming or similar but you might be surprised how much you have to slow up to get it a fixed pitch prop to stop.... I suspect doing so may use up quite a bit of height


Can completely concur with the above. Noticeable difference between idle power, windmilling and prop stopped. Modern Rotax Falkes being geared you only really get prop stopping. No windmilling.
#1884875
This from the DA40 POH

NOTE

The glide ratio is 8.8; i.e., for every 1000 ft (305 meter) of altitude loss the maximum horizontal distance traveled in still air is 1.45 NM (2.68 km). During this the propeller will continue to windmill.

With a stationary propeller the glide ratio is 10.3; this corresponds to a maximum horizontal distance of 1.70 NM (3.14 km) for every 1000 ft altitude. In consideration of a safe airspeed however, this configuration may not be attainable.


In other words, you would get a better glide ratio with a stopped prop, but probably stall trying to stop it.
User avatar
By MichaelP
FLYER Club Member  FLYER Club Member
#1884883
When the crankshaft broke in the Jungmann I raised the nose to stop the prop.
You will not stall if you reduce the G.
So you raise the nose, the prop stops at around 40KIAS, but at the same time you are pitching over lowering the G such that you can fly well below the 1g stall speed.
#1884892
MichaelP wrote:When the crankshaft broke in the Jungmann I raised the nose to stop the prop.
You will not stall if you reduce the G.
So you raise the nose, the prop stops at around 40KIAS, but at the same time you are pitching over lowering the G such that you can fly well below the 1g stall speed.


Although probably not feasible or safe for your average PPL to attempt this during a real forced landing.
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User avatar
By MichaelP
FLYER Club Member  FLYER Club Member
#1885001
Although probably not feasible or safe for your average PPL to attempt this during a real forced landing.


As an instructor I never assumed the student to be stupid until that proved to be the case. Most motivated students can be trained, and whether or not you teach something in the air you should do your best to prepare them for the actual emergency by talking through scenarios the student may encounter.
We train for a benign engine failure, but beyond lack of fuel or carb icing, engine failures are often anything but benign.

If an engine comes off the front of the aeroplane you’re likely dead.
Fortunately for one aeroplane I was told about recently, the loss of a propeller blade caused the carburettors to come off and stop the Rotax 912 before the engine departed the airframe.
By Ibra
#1885002
tomshep wrote:I doubt if a 60 degree angle of bank will work at best glide. I think it would get you deadded.


You have to decide if you are thermaling at min sink or gliding at best glide :lol:
User avatar
By Ben K
#1885019
MichaelP wrote:
Although probably not feasible or safe for your average PPL to attempt this during a real forced landing.


As an instructor I never assumed the student to be stupid until that proved to be the case. Most motivated students can be trained, and whether or not you teach something in the air you should do your best to prepare them for the actual emergency by talking through scenarios the student may encounter.
We train for a benign engine failure, but beyond lack of fuel or carb icing, engine failures are often anything but benign.

If an engine comes off the front of the aeroplane you’re likely dead.
Fortunately for one aeroplane I was told about recently, the loss of a propeller blade caused the carburettors to come off and stop the Rotax 912 before the engine departed the airframe.


Well, by all means don't assume what you like, but I'd personally not teach any PPL to - during the startle factor of an engine failure - *raise* the nose to the stall, or near to it. Then avoid that same stall by bunting to zero g.

All to get a slight increase in glide range during what is very likely to be a rather stressful and quite possibly unexpected situation.

I really don't think the benefits outweigh the danger of intentionally stalling/spin during an engine out scenario, for your 'average PPL'.

You, as a skygod, may of course be quite capable of flying such a manoeuvre.
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User avatar
By MichaelP
FLYER Club Member  FLYER Club Member
#1885031
You, as a skygod, may of course be quite capable of flying such a manoeuvre.

So here we are at the insulting stage.
You need to read the context in which this procedure might be required.

In the air and on the ground I teach lower the nose and attain best glide first and foremost.
But on the ground I also discuss the engine failure and propeller failure possibilities and what you might be best to do under the circumstances.

I was once asked how to balance a propeller which was bolted to the engine.
First of all, take it off the engine... “...not going to happen.”
Then I saw the extent of the bodgery, the daubing of resin, and the fact he had removed one brass leading edge, resined the rotted bits, and riveted the leading edge back on.
I told him he shouldn’t fly it.
If he did fly it, the leading edge on one side was likely to come off, closely followed by the engine, and so I told him how to handle such an emergency.
Primed, I expect that is what saved his life...
He made the front page news with a telling picture.
We can’t prevent all idiots from flying, but at least we can try to save their skins.
User avatar
By Ben K
#1885051
No insult intended, actually.

I'm sure that in some situations, the engine/prop may in fact depart the aircraft.

My original point was I would never teach a student to try and stall the aircraft during a forced landing. But it may well be possible for a more experienced pilot to gain an increase in glide range by stopping the prop (by slowing down close to the stall).

As an instructor I never assumed the student to be stupid until that proved to be the case.


Neither did I...