Another Food Fight

[Bob - S50]

It's been awhile since I started a food fight.  Here's the scenario.

You turn base and for whatever reason, you find that you are high and fast.  While the smart thing to do might be to plan on a go-around, and you may still do that, you aren't ready to give up just yet.  And it turns out that you are able to be on glidepath and on speed just as you arrive at the threshold.  So here is the question...

Which do you do first, get on a normal glidepath or get on speed and WHY?

I don't care which camp you are in about what controls what or how you get there, I'm just curious about people's thoughts.  I know my answer, but I won't post it until later.

[smccray]

1 minute ago, Bob - S50 said:

It's been awhile since I started a food fight.  Here's the scenario.

You turn base and for whatever reason, you find that you are high and fast.  While the smart thing to do might be to plan on a go-around, and you may still do that, you aren't ready to give up just yet.  And it turns out that you are able to be on glidepath and on speed just as you arrive at the threshold.  So here is the question...

Which do you do first, get on a normal glidepath or get on speed and WHY?

I don't care which camp you are in about what controls what or how you get there, I'm just curious about people's thoughts.  I know my answer, but I won't post it until later.

Slow down below 80 kias with full flaps and steepen the glidepath.  Be ready to add power before I get too low.

[Parker_Woodruff]

Get to an appropriate speed first.  The Best Glide Speeds in our Mooneys are generally up around 90 KIAS.  Getting to 70-75 KIAS will result in a better angle of descent to get on glide path.

Taking a greater nose-down attitude pushing 90 KIAS or more will only leave for a greater rush to bleed of speed and you will glide farther.

[steingar]

Depends on how high and how fast.  Landing at TDZ last weekend I didn't plan my descent profile very well, I was way high and way fast too close of the airport.  I just put the aircraft in a 360 while I bled off speed and altitude.  I then entered the downwind with the correct speed and altitude.

Depending on the runway, a bit of excess speed on short final doesn't phase me that much.  If I have some room, I've found that the Mooney, when dirtied up, looses airspeed pretty quickly.  That said, if I'm worried about room its on speed and on altitude or go-around, every time.

[Nokomis449]

Nail 90 Kts and then Slip Slip Slip to the fence.

[RLCarter]

Get the speed under control, your touch down point is going to be further down so floating past even more runway could put you in the giggle weeds

[Simon]

19 minutes ago, Nokomis449 said:

Nail 90 Kts and then Slip Slip Slip to the fence.

I agree.  The forward slip is your friend.  Use it liberally as needed.

[mike_elliott]

Just now, Simon said:

I agree.  The forward slip is your friend.  Use it liberally as needed.

I don't. It depends greatly on your Mooney Model here. Do this in a longbody or Rocket at 75 kts w. full flaps might end up very badly. The forward slip is a tool some use to fix a hosed up stabilized approach, but can cause a tail stall in a Mooney.

[Nokomis449]

9 minutes ago, mike_elliott said:

I don't. It depends greatly on your Mooney Model here. Do this in a longbody or Rocket at 75 kts w. full flaps might end up very badly. The forward slip is a tool some use to fix a hosed up stabilized approach, but can cause a tail stall in a Mooney.

75 Kts?  Where'd that number come from?

Perhaps you're thinking skid and not slip.  A skid can lead to disaster, but a stall during a slip tends to level the wings for you.  Here's an excerpt from someone else's description of a stall during a slip:

Often, if an airplane in a slip is made to stall, it displays very little of the yawing tendency that causes a skidding stall to develop into a spin. A stalling airplane in a slip may do little more than tend to roll into a wings-level attitude. In fact, in some airplanes stall characteristics may even be improved.

And here's a link to a BoldMethod article that says the same thing:

http://www.boldmethod.com/learn-to-fly/aerodynamics/slip-skid-stall/

Otherwise, FOODFIGHT!!!

[smccray]

7 minutes ago, Nokomis449 said:

75 Kts?  Where'd that number come from?

Perhaps you're thinking skid and not slip.  A skid can lead to disaster, but a stall during a slip tends to level the wings for you.  Here's an excerpt from someone else's description of a stall during a slip:

Often, if an airplane in a slip is made to stall, it displays very little of the yawing tendency that causes a skidding stall to develop into a spin. A stalling airplane in a slip may do little more than tend to roll into a wings-level attitude. In fact, in some airplanes stall characteristics may even be improved.

And here's a link to a BoldMethod article that says the same thing:

http://www.boldmethod.com/learn-to-fly/aerodynamics/slip-skid-stall/

Otherwise, FOODFIGHT!!!

We're going to have this discussion again- FOODFIGHT!!! Nokomis- check out a tail plane stall- not the same thing.

Food for thought- Mike Elliot is on my list of people to listen very carefully when flight characteristics come up.  That doesn't mean Mike is going to get them all right, and it doesn't mean that I won't disagree with him, but it does mean that I'm going to think about my position very carefully before weighing in.

[Nokomis449]

4 minutes ago, smccray said:

We're going to have this discussion again- FOODFIGHT!!! Nokomis- check out a tail plane stall- not the same thing.

Food for thought- Mike Elliot is on my list of people to listen very carefully when flight characteristics come up.  That doesn't mean Mike is going to get them all right, and it doesn't mean that I won't disagree with him, but it does mean that I'm going to think about my position very carefully before weighing in.

Mike also mentioned 75 Kts - I said nail 90.  Big difference.

[steingar]

Any airplane can slip.  If you're that worried about a cross control stall then add some speed while you're doing the maneuver.  I don't think there's anything magic about any Mooney.

[mike_elliott]

1 hour ago, smccray said:

We're going to have this discussion again- FOODFIGHT!!! Nokomis- check out a tail plane stall- not the same thing.

Food for thought- Mike Elliot is on my list of people to listen very carefully when flight characteristics come up.  That doesn't mean Mike is going to get them all right, and it doesn't mean that I won't disagree with him, but it does mean that I'm going to think about my position very carefully before weighing in.

Thanks Scott, this is the advice of someone who is one of my real life hero's, Bob Kromer. A couple of very competent, high time pilots were filling the front 2 seats of Dmax's J model (I have a few hours in that bumble bee) when the second last maneuver they did (unsure who was at the controls) was a forward slip, followed by their last maneuver, an unsuccessful unusual attitude recovery. RIP Joel Smith, Max Rae.

From Bob Kromer

From the Mooney List December 2, 2005 by Bob Kromer

 

Slipping a Mooney

 

During development and certification on the M20K 252 at the factory, I encountered the aerodynamic buffeting while slipping on approach as described by Dan Eldridge in his posting on slips in his M20K 231. Obviously, this gets a test pilot's attention and we began an investigation. Thought you might be interested in what we found.  For our slip tests, we flew the M20K, the M20J and the Mooney/Porsche engineering prototypes that were at the factory at the time.  This gave us a good cross section of different aircraft configurations (short/long fuselage, different pitch trim requirements on approach, etc.)  What we found was 1) All airplanes were fine above 85 KIAS in full rudder deflection forward slips, flaps up and flaps down.  2) But somewhere between 80-85 KIAS and lower, AERODYNAMIC BUFFETING FROM THE HORIZONTAL TAIL/ELEVATOR occured in the M20K and the Mooney/Porsche airframes ALONG WITH A SLIGHT LOSS OF ELEVATOR EFFECTIVENESS AND A SLIGHT NOSE DOWN PITCHING MOMENT.  These conditions were worsened with flaps down compared to the flaps up.  Aerodynamic tufting of the horizontal tail revealed what was happening.  In the M20K and the Mooney/Porsche with their more forward CGs, almost full nose up pitch trim is required for a "hands off" approach at the target approach airspeed.  This puts the horizontal stabilizer of the Mooney tail at a high negative angle of attack (to keep the nose up).  With the horizontal tail at this high negative angle of attack and especially with flaps full down, the local airflow over the horizontal tail is getting pretty close to max alpha, the angle of attack where the tail will stall.  I want to emphasize that IN NORMAL FLYING, THERE IS PLENTY OF MARGIN - no need to worry about the tail stalling in your M20K or long body Mooney.  But start slipping the airplane at 85 KIAS and below or have a little ice on that stabilizer leading edge and those margins can get mighty thin.  Combine a slip maneuver with some pretty good yanking on the control wheel in turbulence and you might get a partial tail stall.  We did in flight test - in the M20K the result was buffeting felt in the control wheel and the slight nose down pitching moment.  So my advice from the test pilot's seat is don't go there - especially if you fly a Mooney model that requires lots of nose up pitch trim on the approach.  An aggressive  forward slip in those airplanes with the speed low and the flaps down puts the tail in an extreme airflow condition.  The airplane will warn you with buffeting and a slight pitch down, but who knows - add some ice and look out.  This is not the way to fly your Mooney.  My bottom line opinion - keep the ball near center on the approach and you're flying the Mooney design correctly and safely with the safety margins it was meant to have.

 

Best Regards;

 

Bob Kromer  

[201er]

3 hours ago, Bob - S50 said:

You turn base and for whatever reason, you find that you are high and fast.  While the smart thing to do might be to plan on a go-around, and you may still do that, you aren't ready to give up just yet.  And it turns out that you are able to be on glidepath and on speed just as you arrive at the threshold.  So here is the question...

Which do you do first, get on a normal glidepath or get on speed and WHY?

Neither. It's all about energy and angle of attack. You're too high and probably too fast to boot. That is excess energy. Getting "on speed" won't necessarily help you dump the energy. The way to get rid of energy in a hurry is a steep turn. Another is to increase time. Deliberately overshooting the base to final turn increases your distance and buys you more time. More time and distance to descend. Steepening up the overshot base to final turn and turning in excess of 90 degrees allows you to spend more time in a bank and dissipate more energy. The steeper you turn, the quicker you sink. You're trading lift for bank (horizontal component) so you need more lift to stay level or you sink a lot. Just don't exceed the critical AOA or you'll be on the ground too soon.

Getting slow to increase sink rate will work when wind is calm or steady down the runway. Bad idea if it is unpredictable or gusty because the wind can cause you to stall.

If all else fails or you're not comfortable, just go around.

[Bob_Belville]

11 minutes ago, mike_elliott said:

Thanks Scott, this is the advice of someone who is one of my real life hero's, Bob Kromer. A couple of very competent, high time pilots were filling the front 2 seats of Dmax's J model (I have a few hours in that bumble bee) when the second last maneuver they did (unsure who was at the controls) was a forward slip, followed by their last maneuver, an unsuccessful unusual attitude recovery. RIP Joel Smith, Max Rae.

From Bob Kromer

From the Mooney List December 2, 2005 by Bob Kromer

 

 

Hum, I have more Mooney time than most but playing test pilot while low and slow on final while doing the last GUMP, with one eye on ASI, one eye on VSI, a third eye looking out for cross wind drift, and keeping the AOA indicator in the corner of the eyes on the back of my head, with a sharp eye for runway intrusions by machine or beast... no thanks. 

[Hank]

9 hours ago, Bob - S50 said:

It's been awhile since I started a food fight.  Here's the scenario.

You turn base and for whatever reason, you find that you are high and fast.  While the smart thing to do might be to plan on a go-around, and you may still do that, you aren't ready to give up just yet.  And it turns out that you are able to be on glidepath and on speed just as you arrive at the threshold.  So here is the question...

Which do you do first, get on a normal glidepath or get on speed and WHY?

I don't care which camp you are in about what controls what or how you get there, I'm just curious about people's thoughts.  I know my answer, but I won't post it until later.

Reduce throttle to increase sink rate and recapture glideslope; reducing speed slightly below target will help, too.

If needed, extend downwind some, as airspeed and altitude will not decrease rapidly or immediately. The longer pattern gives more time on downwind and final to fix things. I'm typically 1/2 nm out on downwind, so a couple hundred yards extension can make a difference. I never add more than 1/4 nm unless directed by Tower [who has turned me downwind 7 nm out, led me into a 10 nm final approach, then asked me to keep my speed up for the airliner following . . . ].

If that doesn't work [and I'll know by halfway down final], then I make my second downwind entry correctly and don't have problems!    Got that t-shirt . . .  Life is so much easier when you are on speed and altitude when wanting to land.

P.S.--drop more flaps right away, and leave them down until it's under control again. 

Edited June 21, 2017 by Hank

[midlifeflyer]

As others pointed out, it's about overall energy. If you really are going to try to salvage that landing without doing steep turns 500 AGL and slipping isn't your cup of tea, your best bet is going to be your airplane's (Mooney, Cessna, Piper, Bonanza, Cirrus, whatever) short field landing configuration. By design, that configuration decreases your airspeed and steepens your descent in a way that minimizes the overall energy and allows you to stop shortly after touchdown. You are effectively doing both - controlling both airspeed and glidepath together (you know, the old "pitch + power (+ configuration) = performance" thing?

[smccray]

1 hour ago, Nokomis449 said:

Mike also mentioned 75 Kts - I said nail 90.  Big difference.

Yep- you're right.  Mike did change the parameters of the slip.

Extracting from Bob Kromer's Mooney List post (which now that I read I recognize from prior discussions):

13 minutes ago, mike_elliott said:

So my advice from the test pilot's seat is don't go there - especially if you fly a Mooney model that requires lots of nose up pitch trim on the approach.  An aggressive  forward slip in those airplanes with the speed low and the flaps down puts the tail in an extreme airflow condition.  The airplane will warn you with buffeting and a slight pitch down, but who knows - add some ice and look out.  This is not the way to fly your Mooney.  My bottom line opinion - keep the ball near center on the approach and you're flying the Mooney design correctly and safely with the safety margins it was meant to have.

There are a lot of accomplished aviators here and a lot of people to learn from.  I don't know everyone here, and it certainly is possible that better advise will come out pilots on MooneySpace than advice from Mike Elliot / Bob Kromer.  However, when someone advocates (which is what I read above) using a forward slip which runs contrary to advise from a former Mooney test pilot, that doesn't make sense to me.  Keeping airspeed above 90 knots appears to keep the plane outside of the range where buffeting was observed in a forward slip, but slipping the plane runs contrary to advise.  It's certainly a corner of the flight envelope, but my reading is that it's a somewhat dangerous corner of the flight envelope and a corner that I choose to stay away from.

[Nokomis449]

He also said this in the article about slipping a Mooney (emphasis is his) - 

 I want to emphasize that IN NORMAL FLYING, THERE IS PLENTY OF MARGIN - no need to worry about the tail stalling in your M20K or long body Mooney.

So a tailplane stall IN NORMAL FLYING is not going to occur at 90kts, so we can take that off the table.  I've read plenty of NTSB reports, including the accident mentioned.  If you want to scare yourself about how often people make mistakes in airplanes, check out http://www.kathrynsreport.com/ daily for your daily dose of what not to do.  I've also read a million Mooney articles by Bob Cromer and I highly respect his work, including this particular article.  In fact, I'm pretty sure my 90kt speed is directly due to this very article which I first read long ago.  I was lucky enough to learn to fly my Mooney from a CFI who had owned the same Mooney, and who has taught me aerobatics (not in the Mooney), upset recovery (in the Mooney), and everything else.  I am just as comfortable slipping my Mooney at 90kts as I am slipping on my Wrangler jeans.  I have personal limits - when landing, I only do it on final, after getting into landing configuration, and I keep the speed nailed.  I go into a lot of small grass fields where slipping and short field landings are the only/best way to get in.  I've been taken to the limits of the Mooney's performance envelope and shown what happens when I exceed them.  If everybody had an instructor as good as him, slips and stalls would be respected but not feared.  I regularly practice slow flight (minimum controllable airspeed), stall at altitude both power on and power off, do 50deg turns, and other maneuvers that keep me proficient in the Mooney.  I know the difference between a slip and a skid.  So let me rephrase my original answer:  I would slow to 90kts, configure for landing, and when I'm established but high on final I would SLIP SLIP SLIP until I decide I can safely land or initiate a go around.

(slings some cake)

[TonyK]

I would get dirty, go for speed and then slip into place on the glide path.  

[carusoam]

1) Slow down first.

2) This buys you more time between here and the runway.

3) Vertical speed is in fpm. More minutes means you can descend more.

4) Then work the efficiency angle, below Best glide is less efficient because your drag has aerodynamically increased.

5) throw in the speed brakes for good measure.

 

Mooneys are all about speed and efficiency.... Until you are high on final approach!

PP ideas only, not a CFI...

Best regards,

-a-

Edited June 22, 2017 by carusoam

[bradp]

I was left high on a clearance to a visual approach and I didn't slow down as I was going down to pattern altitude on an extended base.  Here's what I did - not necessarily advocating it but it worked.  I slipped on base leg down to pattern altitude. I was fast initially faster than gear speed, then undid the slip to extend gear (another useful piece of drag)  and my descent rate was >1200fpm.  Without speed brakes the forward slip is one of the most effective tools to simultaneously go down and slow down given the constraints that Bob Kromer outlines.  Once lower I made a normal turn to final and bled some energy in the turn down to my normal base to final speed of 90mph, putting in flaps as I was slowing.  Then I stayed at altitude (potential energy) to bleed off additional kinetic energy with full flaps.  Now with the extra flaps and a little more nose up than usual and idle you are firmly planted on the back side of L/D max.  It's the same as what the big jets and such (i.e. That ill-fated colgan flight, asiana) experience - you have more drag than at a higher IAS and you can turn that change from your drag pocket into loss of potential energy from the other pocket.  So far - in my relative inexperience compared to the gurus on the board - the adage of slow down before go down has worked pretty well.  

[Yetti]

High turning base

Gear was put down at down threshold downwind - I will be slowing down

Put flaps out now.

Reduce throttle a bit more

turn final - If still high - put full flaps out

engine to idle.

Evaluate winds.   If good nose wind, won't really worry about it.   If light winds may start planning for a go around.

[Yetti]

Every landing is like a box of chocolates.

[bonal]

I'm not sure why I clicked to reply I dont really have much to add but it sure seems like many of the places we fly into dont always give  you a text book type entry into the pattern. I like the box of chocolates approach being adaptable to any situation seems best.  I wonder if there are same kind of discussions about how best to approach and dock a boat on the boat web sites