Calculating Approach speed --additions
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I tell you what Mad Jock, to save me the trouble of finding a FI and seeing as I have the benefit of your wealth of knowledge right now, why don't you explain how a centre mounted engine can energise the airflow over the wings that are located to the left and right of the propeller generated slipstream? Please, I'd be really grateful
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Nope i think is safer for all concerned if you spent some quality time with an FI.
I will give you a hint its the reason why tommahawks are pish for soft field and short field takeoff techniques.
I will give you a hint its the reason why tommahawks are pish for soft field and short field takeoff techniques.
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You've got yourself to the point that you can't expand any further without shooting yourself in the foot haven't you? Slipstream over the tail doesn't count, all that does is increase elevator/rudder authority (rudder only on the T tailed tomahawk) so you can increase angle of attack on an already overburdened wing!
And what evidence do you have that i'm not an FI?
I rest my case.
And what evidence do you have that i'm not an FI?
I rest my case.
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Originally Posted by Rans S9
"From those numbers I think we might be considering the venerable PA28, perhaps this might allay some fears"
---I think you might be wrong and no it doesn't allay any fears. The figures were chosen for a hypothetical trainer (I've never flown A PA-- anything.) SO if the Vso is 50 1.3 is approx 68. Agreed being a low hours PPL I'd be flying 70 (not for the kids, or plague of frogs, just because there is likely to be a mark on the ASI to indicate it) but you know what PPruners' are like some wag would have corrected us saying it was actually 68! This makes the energy excess over the stall slightly less "surprising".
"Lastly, when did you last stall an aircraft - you might remember that it actually takes a pretty concerted effort
"
--- 6 months ago. But then I haven't flown since. Actually as I remember it doesn't but then my airplane has a powerful elevator in part to help bring it to the stall quickly. In other aircraft the effort I supposed depends and how fastidious you are in your trimming. My memory maybe playing me tricks but since I'll be seeing an instructor down your way(White Waltham) next week for a pre-reason wake-up call (involving almost certainly repeated departures in almost every conceivable aircraft attitude/energy state...OH JOY!?!) I'll let you know.
---I think you might be wrong and no it doesn't allay any fears. The figures were chosen for a hypothetical trainer (I've never flown A PA-- anything.) SO if the Vso is 50 1.3 is approx 68. Agreed being a low hours PPL I'd be flying 70 (not for the kids, or plague of frogs, just because there is likely to be a mark on the ASI to indicate it) but you know what PPruners' are like some wag would have corrected us saying it was actually 68! This makes the energy excess over the stall slightly less "surprising".
"Lastly, when did you last stall an aircraft - you might remember that it actually takes a pretty concerted effort
"--- 6 months ago. But then I haven't flown since. Actually as I remember it doesn't but then my airplane has a powerful elevator in part to help bring it to the stall quickly. In other aircraft the effort I supposed depends and how fastidious you are in your trimming. My memory maybe playing me tricks but since I'll be seeing an instructor down your way(White Waltham) next week for a pre-reason wake-up call (involving almost certainly repeated departures in almost every conceivable aircraft attitude/energy state...OH JOY!?!) I'll let you know.
It will always be possible to construct a scenario where you're too slow; as pace said you only have so much power at your disposal. However, I will stand by my assertion that *most* aircraft are flown over the hedge too fast.
As for stalling, you'll still need an 'abnormally' rearward stick position. If you don't move the stick that far back, you won't stall - trim, control effort and everything else aside, at 1G and the same load, the aircraft will stall at the same stick position - it's an extension of the trim sets speed principle.
Enjoy your departures.. they're fun, honest
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The increase in wash from the increase of RPM, which travels down the aircraft fusilage causes an apparent decrease in the angle of attack as it passes the wing root section. This is because the thrust vector is along the physical longitudinal axis of the aircraft. The pilot will see that as an increased attitude of the stall but this has no effect at all on the critical angle of attack. If the pilot maintains the intial attitude they have in effect decreased the angle of attack so if they were all ready at the critical angle of attack at xxknts they would have to increase the angle of attack to get back to the critical angle of attack which would be at a reduced airspeed.
And the hint was that the tommy has a T-tail which means you don't get any advantage from the wash which means you can't wheelie it on high power.
Have a look at you principles of flight before you do another effects of controls or stalling please.
And the hint was that the tommy has a T-tail which means you don't get any advantage from the wash which means you can't wheelie it on high power.
Have a look at you principles of flight before you do another effects of controls or stalling please.
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The increase in wash from the increase of RPM, which travels down the aircraft fusilage causes an apparent decrease in the angle of attack as it passes the wing root section.
And the hint was that the tommy has a T-tail which means you don't get any advantage from the wash which means you can't wheelie it on high power.
Slipstream over the tail doesn't count, all that does is increase elevator/rudder authority (rudder only on the T tailed tomahawk) so you can increase angle of attack on an already overburdened wing!
And why is it that when people run out of arguments/ideas/knowledge they resort to insults or personal attacks?
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VERY GOOD. thereby leaving the tips at a higher AOA which is a recognised technique for entering a s
We are talking about an approach to landing here, where nothing like that AOA will should occur.
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We are talking about an approach to landing here, where nothing like that AOA will should occur
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Oh please! We're not talking about back of the power curve 'bush' approaches here, we're talking about do I approach at 65 or 75kts. That's the kind of irrational paranoia that sends people through the far hedge.
And, for the record, a spin requires yaw rate AND excessive back stick, AND persistent mishandling.
And, for the record, a spin requires yaw rate AND excessive back stick, AND persistent mishandling.
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Aren't we. I hadn't realised the approach parameters had been laid down as 65 or 75 knots. Thanks for the clarification.
Well aware of how a spin occurs thanks, I'm just a little concerned at the number of people who are advocating the same approach speed WHATEVER the conditions are, be it calm or 25kt G40. An example of mob mentality.
Incidentally, in that condition, adding half the gust would give an increase in airspeed of 7.5 kts but an overall REDUCTION in groundspeed of - Approach speed,say 65kt+7.5 =72.5 MINUS the mean HWC of 25kt = 47.5 kts. Compared to a calm day and a groundspeed equalling airspeed of 65 knots.
So 17.5 kts LESS groundspeed on a windy day, and a safety margin, what am I thinking?
Your pontification about going through the far hedge is nonsense!
Well aware of how a spin occurs thanks, I'm just a little concerned at the number of people who are advocating the same approach speed WHATEVER the conditions are, be it calm or 25kt G40. An example of mob mentality.
Incidentally, in that condition, adding half the gust would give an increase in airspeed of 7.5 kts but an overall REDUCTION in groundspeed of - Approach speed,say 65kt+7.5 =72.5 MINUS the mean HWC of 25kt = 47.5 kts. Compared to a calm day and a groundspeed equalling airspeed of 65 knots.
So 17.5 kts LESS groundspeed on a windy day, and a safety margin, what am I thinking?
Your pontification about going through the far hedge is nonsense!
Actual A of A isn't normally the same at wing tips - if normal wash-out is designed in.
[AFIR to ensure the roots stall first, maybe give rumble to let you know it's close to stall, yet allow the outer wing to keep flying.
I'm NOT an FI !!
mike.
[AFIR to ensure the roots stall first, maybe give rumble to let you know it's close to stall, yet allow the outer wing to keep flying.
I'm NOT an FI !!
mike.
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VERY GOOD. thereby leaving the tips at a higher AOA which is a recognised technique for entering a spin
The size of gust that would get you anywhere near trouble would be classed as a windshear event. The only option you have is to go around.
And I haven't run out arguments/ideas/knowledge.
Or shall we just agree that if your talent limited and out of practise to the point you shouldn't be flying the aircraft in the conditions (the fact you are talent limited will mean you won't be able to hold the airspeed anyway) you can add what ever makes you happy to the approach speed. And then its luck of the draw if you nose wheel it in or go off the end or off the side. Which is pretty much the recurring theme in alot of accident reports of GA aircraft.
If you are competent and fit to be the PIC of the aircraft in the conditions you fly the book approach speed.
O and to add I have landed a tommy in 25G40 with full flap, normal approach speed and not a chirp out of the stall warner
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Do any of you academic people know the speed where a typical light aircraft will land nose wheel first, leaving the main wheels in the air.
Vref33 + 11 is the only one I know (so all the additions for surface wind wife, kids, granchildren and the dog could never be above 11kts (not a light a/c)
Vref33 + 11 is the only one I know (so all the additions for surface wind wife, kids, granchildren and the dog could never be above 11kts (not a light a/c)
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I know we will never be spot on but even if you drop 20knt's below your approach speed your not going to stall you might get the warner to chirp but thats about it. By that point you should be going around anyway.
Go and try it at altitude if you don't believe us. In fact every one that thinks you are going to stall if you get a 10knts gust go and try it. Look at the attitude just before the stall have a look at the airspeed as well. Remember the attitude and if you ever get near it go around. Try it with different flap settings, try and stall it as well being cack handed pulling the controls back without adding power. The try it again this time with power see what the difference is. So many instrutors teach stalling as a series of exercises for the test. The recognition of an impending stall is over looked, know the danger attitudes for the different stages of flight. To be honest that would be a cracking hour with an instructor flight.
There are very very few GA aircraft stall in or spin in on final approach. There are many many times more taking nose wheels out or going off road on landing.
I say again it is an increase in wind speed which causes most accidents not a decrease. Be it far out and the aircraft gets lifted high on profile and the pilot pushes a bad approach or in the flare with PIO's or getting pushed sideways off the runway.
Go and try it at altitude if you don't believe us. In fact every one that thinks you are going to stall if you get a 10knts gust go and try it. Look at the attitude just before the stall have a look at the airspeed as well. Remember the attitude and if you ever get near it go around. Try it with different flap settings, try and stall it as well being cack handed pulling the controls back without adding power. The try it again this time with power see what the difference is. So many instrutors teach stalling as a series of exercises for the test. The recognition of an impending stall is over looked, know the danger attitudes for the different stages of flight. To be honest that would be a cracking hour with an instructor flight.
There are very very few GA aircraft stall in or spin in on final approach. There are many many times more taking nose wheels out or going off road on landing.
I say again it is an increase in wind speed which causes most accidents not a decrease. Be it far out and the aircraft gets lifted high on profile and the pilot pushes a bad approach or in the flare with PIO's or getting pushed sideways off the runway.
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There are very very few GA aircraft stall in or spin in on final approach. There are many many times more taking nose wheels out or going off road on landing.
Luckily, this decision is taken away from me because both as a commercial pilot and as an instructor I have operating and training manuals that state exactly how many knots to add to the book figures...
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Yes. But every stall-in and every spin-in results in a casualty. Not the bent nosewheels and the bent propellers. They can bend as many of them as they want, I couldn't care less.
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Luckily, this decision is taken away from me because both as a commercial pilot and as an instructor I have operating and training manuals that state exactly how many knots to add to the book figures...
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Fly the speeds in the book with good technique (by that I mean correctly trimmed) and you don't go far wrong.
Interesting comments about T tails, lets have a look at the Arrow and how the T tail handles different at low speeds compared to the straight tail (more control authority - out of the turbulent airflow from a wing at low speeds and high angle of attacks)
Anyone remember the incidents with Tomahawks killing people when they spun in due to poor handling. Spinning is much more than yaw and low airspseed, an aircraft can be prone to spinning due to design (factors include wing section and tail moment / authority). Anyone wondered why the only time Tomahawks were spun deliberatly in the UK was during a CofA airtest (to ensure they recovered) Anyone who is writing who has been in one when it has been spun will tell you they entered easily and went flat within two rotations and you had to use correct technique to recover or you overstressed the airframe. You could look over your shoulder and see the fueslage skin buckling.
And yes I speak from first hand experience - I have in my log book 43 CofA test flights on the terrorhawk which included full spin and recovery.
I copy below part of the AOPA report of 1997 into the handling of the Tomahawk.
Tomahawk Safety Review
By Bruce Landsberg
All aircraft have reputations. For some they take years to evolve, while for others the reputations develop quickly. From the beginning the Piper PA-38 Tomahawk attracted attention. When it was introduced in 1977, it looked different from any other two-place trainer; and it flew differently.
It didn't take long for the airplane to get a reputation. The handling characteristics stemmed from a relatively new airfoil known as the GAW-1, which is quite efficient but in certain configurations has rather abrupt stall and spin qualities. Additionally, the PA-38 was one of the first light airplanes to sport a T-tail. Both of these items cause the Tomahawk to fly a little differently than other light trainers. The PA-38 is the eleventh in a continuing series of safety reviews that the AOPA Air Safety Foundation has undertaken in order to evaluate the safety records of particular aircraft.
The area of greatest interest to ASF was the aircraft's safety record. The PA-38 has been involved in a significantly higher number of stall/spin accidents than comparable aircraft — the Cessna 150/152, the Beech Skipper, and the Grumman AA-1 trainer. The latter two are not present in great numbers in the fleet, but the Cessnas have had a virtual lock on the two-place trainer market for decades.
The Tomahawk has a reputation for being "aggressive" in a stall and for spinning readily if yaw is introduced at the right time. It also has a tendency to drop a wing in the stall — and if the pilot mishandles the rudder, elevator, or ailerons, a spin may rapidly develop. None of this is news. When the PA-38 was introduced, it was clear that this aircraft required a different approach from that applied to the relatively docile Cessnas. Pilots who fail to understand that the PA-38 handles much differently in the stall and spin regime may be surprised by the aircraft's response.
The adage "Be careful what you ask for, because you just might get it" probably applies here. According to Piper, in the course of designing the Tomahawk, the company surveyed 10,000 flight instructors. Forty percent of the respondents asked for a more readily spinnable aircraft than the Cessna150/152. By design, the PA-38 does exactly that
Interesting comments about T tails, lets have a look at the Arrow and how the T tail handles different at low speeds compared to the straight tail (more control authority - out of the turbulent airflow from a wing at low speeds and high angle of attacks)
Anyone remember the incidents with Tomahawks killing people when they spun in due to poor handling. Spinning is much more than yaw and low airspseed, an aircraft can be prone to spinning due to design (factors include wing section and tail moment / authority). Anyone wondered why the only time Tomahawks were spun deliberatly in the UK was during a CofA airtest (to ensure they recovered) Anyone who is writing who has been in one when it has been spun will tell you they entered easily and went flat within two rotations and you had to use correct technique to recover or you overstressed the airframe. You could look over your shoulder and see the fueslage skin buckling.
And yes I speak from first hand experience - I have in my log book 43 CofA test flights on the terrorhawk which included full spin and recovery.
I copy below part of the AOPA report of 1997 into the handling of the Tomahawk.
Tomahawk Safety Review
By Bruce Landsberg
All aircraft have reputations. For some they take years to evolve, while for others the reputations develop quickly. From the beginning the Piper PA-38 Tomahawk attracted attention. When it was introduced in 1977, it looked different from any other two-place trainer; and it flew differently.
It didn't take long for the airplane to get a reputation. The handling characteristics stemmed from a relatively new airfoil known as the GAW-1, which is quite efficient but in certain configurations has rather abrupt stall and spin qualities. Additionally, the PA-38 was one of the first light airplanes to sport a T-tail. Both of these items cause the Tomahawk to fly a little differently than other light trainers. The PA-38 is the eleventh in a continuing series of safety reviews that the AOPA Air Safety Foundation has undertaken in order to evaluate the safety records of particular aircraft.
The area of greatest interest to ASF was the aircraft's safety record. The PA-38 has been involved in a significantly higher number of stall/spin accidents than comparable aircraft — the Cessna 150/152, the Beech Skipper, and the Grumman AA-1 trainer. The latter two are not present in great numbers in the fleet, but the Cessnas have had a virtual lock on the two-place trainer market for decades.
The Tomahawk has a reputation for being "aggressive" in a stall and for spinning readily if yaw is introduced at the right time. It also has a tendency to drop a wing in the stall — and if the pilot mishandles the rudder, elevator, or ailerons, a spin may rapidly develop. None of this is news. When the PA-38 was introduced, it was clear that this aircraft required a different approach from that applied to the relatively docile Cessnas. Pilots who fail to understand that the PA-38 handles much differently in the stall and spin regime may be surprised by the aircraft's response.
The adage "Be careful what you ask for, because you just might get it" probably applies here. According to Piper, in the course of designing the Tomahawk, the company surveyed 10,000 flight instructors. Forty percent of the respondents asked for a more readily spinnable aircraft than the Cessna150/152. By design, the PA-38 does exactly that
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And on a lighter note. As a low hours PPL I have learnt one thing from this thread.
Instructors are neither gods nor always right, if they can argue they will and at the expense of some one like me, who read these threads hoping to improve my flying skills. I am more confused now than I was at the start. Thanks for not a lot.
Instructors are neither gods nor always right, if they can argue they will and at the expense of some one like me, who read these threads hoping to improve my flying skills. I am more confused now than I was at the start. Thanks for not a lot.
