Landing with speed brakes deployed

[Rotorhead]

I could see both sides of the road on this topic. I would argue that when someone is executing a go-around, that person was most likely not planning to do it when they started the approach. Meaning, a dog came across the runway, the landing became unstable, you ran out of runway while floating, etc. so in nearly any case when a go-around is started, the PIC's situational awareness is already degraded.

In this 'abnormal' situation, having one less configuration change would probably be ideal. Not having to think about retracting the air brakes or having to accept that moment of degraded performance is a better place to be.  I'm not saying it's impossible by any means to retract air brakes during a go-around, but more so that if someone is looking for safety vs performance, ie. shortening a landing roll, I'd probably go for landing without the airbrakes extended. 

Sure, added parasitic drag will help to shorten ground roll, but it has never helped anyone during a go-around.

-KC

Edited January 6, 2024 by Rotorhead

[PT20J]

16 hours ago, dkkim73 said:

I'm sorry, as you seem pretty dialed-in aeronautically, but doesn't parasitic drag go up as a higher power than 2? 

The reason that might matter is that those little dudes are pretty small (FWIW I was quoted a very small equivalent flat-plate area of the Type S when clean, so it's a big difference at speed when they pop out) and things are slow in the landing regime. 

Just following on to the discussing of speed brakes vs. true spoilers (the ground spoilers on a big wing will actually result in significant down force as I understand). 

D

Drag and lift are both functions of dynamic pressure, q. 

q = 1/2 p V², where p = air density and V = true airspeed.

An aeronautical engineer and CFD specialist friend calculated the equivalent flat plate area for a Mooney as 2.91 ft². (For comparison, a Bonanza is about 3.50)

Equivalent flat plate area is somewhat of a misnomer. It is a figure of merit used to compare different aerodynamic shapes. It is defined as the parasitic drag force divided by q. That turns out to have the dimensions of ft², so it is referred to as an area. Because it is not an "aerodynamic" shape, an actual flat plate of the same area will have about 1.28 times as much drag.

Without a wind tunnel measurement, or CFD calculation, it would be difficult to figure out how much the speed brakes add to the aircraft equivalent flat plate area because the shape of the blades and the holes will create turbulence and vortices that will extract energy from the airflow which will show up as drag.

Skip

[LANCECASPER]

5 minutes ago, PT20J said:

Drag and lift are both functions of dynamic pressure, q. 

q = 1/2 p V², where p = air density and V = true airspeed.

An aeronautical engineer and CFD specialist friend calculated the equivalent flat plate area for a Mooney as 2.91 ft². (For comparison, a Bonanza is about 3.50)

Equivalent flat plate area is somewhat of a misnomer. It is a figure of merit used to compare different aerodynamic shapes. It is defined as the parasitic drag force divided by q. That turns out to have the dimensions of ft², so it is referred to as an area. Because it is not an "aerodynamic" shape, an actual flat plate of the same area will have about 1.28 time as much drag.

Without a wind tunnel measurement, or CFD calculation, it would be difficult to figure out how much the speed brakes add to the aircraft equivalent flat plate area because the shape of the blades and the holes will create turbulence and vortices that will extract energy from the airflow which will show up as drag.

Skip

Ask a simple question . . . get a simple answer  . . lol

Thanks for your expertise

[PT20J]

2 hours ago, donkaye said:

I, too, have written an article on speed brakes that can be found on my website at https://donkaye.com/useful-aviation-articles.  That article pretty well describes how to use speed brakes.  I do automatically "pop" them on touchdown.  I have found them be effective from touchdown speed to about 75% of touchdown speed.  Below 200 feet, if you are too fast for the runway length, I'd recommend going around rather than applying the speed brakes.  You will get an immediate 200 ft/min increase in descent rate that could slam you into the ground at that altitude.

Thanks, Don. Thoughtful article.

I now pull the CB on the speed brakes whenever I turn on the pitot heat. Once I brushed the yoke-mounted switch when reaching to change the heading bug while making a 180 to retreat from an inadvertent icing encounter climbing over the Siskiyou Mountains, and although I immediately stowed them, and the icing was light, the left one did not fully retract until I got well below the freezing level. I would hate to think what would have happened if the icing had been heavier and the brakes deployed longer.

[Danb]

12 hours ago, donkaye said:

I, too, have written an article on speed brakes that can be found on my website at https://donkaye.com/useful-aviation-articles.  That article pretty well describes how to use speed brakes.  I do automatically "pop" them on touchdown.  I have found them be effective from touchdown speed to about 75% of touchdown speed.  Below 200 feet, if you are too fast for the runway length, I'd recommend going around rather than applying the speed brakes.  You will get an immediate 200 ft/min increase in descent rate that could slam you into the ground at that altitude.

Nice articles Don, the one regarding the speed brakes answered my questions. I’ll read the other articles great information.

D

[GeeBee]

10 hours ago, PT20J said:

Drag and lift are both functions of dynamic pressure, q. 

q = 1/2 p V², where p = air density and V = true airspeed.

An aeronautical engineer and CFD specialist friend calculated the equivalent flat plate area for a Mooney as 2.91 ft². (For comparison, a Bonanza is about 3.50)

Equivalent flat plate area is somewhat of a misnomer. It is a figure of merit used to compare different aerodynamic shapes. It is defined as the parasitic drag force divided by q. That turns out to have the dimensions of ft², so it is referred to as an area. Because it is not an "aerodynamic" shape, an actual flat plate of the same area will have about 1.28 time as much drag.

Without a wind tunnel measurement, or CFD calculation, it would be difficult to figure out how much the speed brakes add to the aircraft equivalent flat plate area because the shape of the blades and the holes will create turbulence and vortices that will extract energy from the airflow which will show up as drag.

Skip

I would venture to say without calculation, that the holes create more drag than the flat plate.

[GeeBee]

13 hours ago, donkaye said:

I, too, have written an article on speed brakes that can be found on my website at https://donkaye.com/useful-aviation-articles.  That article pretty well describes how to use speed brakes.  I do automatically "pop" them on touchdown.  I have found them be effective from touchdown speed to about 75% of touchdown speed.  Below 200 feet, if you are too fast for the runway length, I'd recommend going around rather than applying the speed brakes.  You will get an immediate 200 ft/min increase in descent rate that could slam you into the ground at that altitude.

Thanks for validating my technique!

[Fly Boomer]

15 hours ago, PT20J said:

An aeronautical engineer and CFD specialist friend calculated the equivalent flat plate area for a Mooney as 2.91 ft². (For comparison, a Bonanza is about 3.50)

These numbers from an article by Richard "Zef" Zephro (unattributed) come pretty close to the numbers from your friend:

Aircraft        Flat Plate sq. ft.
--------------  ------------------
Mooney 201      2.81
Beech Bonanza   3.47
Piper Arrow     4.64
Cessna 182      5.27
Beech Sierra    5.02
Piper Warrior   5.83
Cessna 172      6.25
Cessna 152      6.14
Beech Skipper   6.36
Piper Tomahawk  6.64
 

[ZuluZulu]

22 hours ago, LANCECASPER said:

I use them occasionally to land especially if I find myself a little fast on final. I think it helps with float a little. I think after awhile you get a seat-in-the-pants feel for how final approach is feeling,  and looking outside, if it feels like I need it, I use them.

Coincidentally this last week I re-read a Robert Goyer article in Flying from 15 years ago shortly after the Acclaim S was introduced. Here's what he had to say: "The speed brakes also help in one other respect, in landing. You’ve probably heard that Mooneys are hard airplanes to land, and it’s true. Unless, that is, you do things right, in which case they’re easy to land. The key, as you know if you’ve flown them, is to control your airspeed. On landings where I did this, I was overjoyed with the result. On landings where I was a little fast, the results weren’t pretty. By using the speed brakes, however, the airplane tends to float a lot less. By the end of the week I was using the blades on every landing. With them, speed control is still important, but slightly less so."

Link to the Article: https://www.flyingmag.com/pilot-reports-pistons-mooney-acclaim-type-s/

Lance, I like you, and I hope deadnaming her was an honest mistake and not trolling for a political argument, given the name of the author on the page you linked is clearly Isabel Goyer, not Robert. To use that name and pronoun that aren’t even on the article instead seems like it might be intentional. She’s made her preference clear for quite some time now. If this was just a mistake, then accept my apologies.

But if not, haven’t we all argued about this enough now? Let’s leave this pointless complaining that trans people exist back in 2023. Happy 2024 to everyone and respect to all. Yes, all, even those some of you may not like. We’re all in this together. 

/flame suit on

[LANCECASPER]

Lance, I like you, and I hope deadnaming her was an honest mistake and not trolling for a political argument, given the name of the author on the page you linked is clearly Isabel Goyer, not Robert. To use that name and pronoun that aren’t even on the article instead seems like it might be intentional. She’s made her preference clear for quite some time now. If this was just a mistake, then accept my apologies.
But if not, haven’t we all argued about this enough now? Let’s leave this pointless complaining that trans people exist back in 2023. Happy 2024 to everyone and respect to all. Yes, all, even those some of you may not like. We’re all in this together. 
/flame suit on

 

Lance, I like you, and I hope deadnaming her was an honest mistake and not trolling for a political argument, given the name of the author on the page you linked is clearly Isabel Goyer, not Robert. To use that name and pronoun that aren’t even on the article instead seems like it might be intentional. She’s made her preference clear for quite some time now. If this was just a mistake, then accept my apologies.
But if not, haven’t we all argued about this enough now? Let’s leave this pointless complaining that trans people exist back in 2023. Happy 2024 to everyone and respect to all. Yes, all, even those some of you may not like. We’re all in this together. 
/flame suit on

I'm not sure what you're implying. I used the name Robert since Flying Magazine (print copy) says that’s who wrote the article. When Flying digitized the article the formatting may have switched that around. Isabel Goyer may have taken some of the pictures for the article, since she's a photographer. I think she may have done some writing and editing for Plane and Pilot and Flying in the past.

However, below you'll see that Robert Goyer was the author of the article and, at the time, the Senior Editor of Flying. He was later in 2010 named the Editor-in-Chief of Flying. (https://www.flyingmag.com/news-goyer-takes-over-top-spot-flying/). 








 

[LANCECASPER]

https://www.ainonline.com/aviation-news/business-aviation/2018-10-13/isabel-goyer-lands-nbaa-bace

Ok, I'm not the brightest bulb in the chandelier. It turns out that Robert is now Isabel. No intention of offending anyone earlier. (i now know the definition of "deadnaming", first time I've ever heard that term.)

However Robert was the person's name when the article was written in 2009.

 

[Andy95W]

You’re doing better than me, Lance.  I doubt I would have even noticed that the last name was the same. 

[Jetpilot86]

42 minutes ago, LANCECASPER said:

https://www.ainonline.com/aviation-news/business-aviation/2018-10-13/isabel-goyer-lands-nbaa-bace

Ok, I'm not the brightest bulb in the chandelier. It turns out that Robert is now Isabel. No intention of offending anyone earlier. (i now know the definition of "deadnaming", first time I've ever heard that term.)

However Robert was the person's name when the article was written in 2009.

 

Well, I'm just dense enough to have assumed Isabel was Mrs. Goyer.  Clearly I'm asleep, or is it not woke? <shrugs>

[LANCECASPER]

1 minute ago, Jetpilot86 said:

Well, I'm just dense enough to have assumed Isabel was Mrs. Goyer.  Clearly I'm asleep, or is it not woke? <shrugs>

That was my first thought also.

[Jetpilot86]

On 1/5/2024 at 12:53 PM, Danb said:

I haven’t landed with the speed brake’s deployed but talked with a couple that always landed in that configuration. I was told by the previous owner of my Acclaim that he always used them.

Who  are the long body pilots that land with them deployed and the results. Is float diminished, landing roll any change in handling characteristics. I didn’t see anything in my POH I’d like to know if there is any benefit. The person who purchased my Bravo is being taught landing with them deployed.

D

If I ever get to use mine I'll let you know.  My left one failed on the first runup when I picked up the plane out of prebuy as the new owner.  Hoping it's an easy fix vs the $2k overhaul when I get to DMax in a couple weeks for my annual....

[LANCECASPER]

2 minutes ago, Jetpilot86 said:

If I ever get to use mine I'll let you know.  My left one failed on the first runup when I picked up the plane out of prebuy as the new owner.  Hoping it's an easy fix vs the $2k overhaul when I get to DMax in a couple weeks for my annual....

This is something that is missed on almost every annual. The Instructions for continued airworthiness on the speed brakes say that the cartridge needs to come out (not difficult) and that the worm drive (not the clutch) needs to be lubricated with Aeroshell 22 every year (do NOT use any spray lubricant any where near the speed brakes). When the grease gets old and hard the mechanism becomes very slow until it fails. Cleaning it out and re-greasing with Aeroshell 22 and exercising the brakes will quiet them down and often get you many more years of service. 

[Jetpilot86]

1 minute ago, LANCECASPER said:

This is something that is missed on almost every annual. The Instructions for continued airworthiness on the speed brakes say that the cartridge needs to come out (not difficult) and that the worm drive (not the clutch) needs to be lubricated with Aeroshell 22 every year (do NOT use any spray lubricant any where near the speed brakes). When the grease gets old and hard the mechanism becomes very slow until it fails. Cleaning it out and re-greasing with Aeroshell 22 and exercising the brakes will quiet them down and often get you many more years of service. 

When it failed, it lurched it's way 1/2 way up then retracted.  I ended up pulling the breaker since having one up is a no-no per the manual.  The other day I was looking at the left one with the switch pushed by accident and I could hear the motor? trying to engage the SB itself, but it wasn't moving.  Hopefully, your solution will fix it.  Before I bought her, she'd been sitting out for almost 2 years in the NE waiting for parts from Mooney leading probably to this and some heavily oxidized paint.  The SB's worked fine on the test flight, of course....

[N201MKTurbo]

3 hours ago, Jetpilot86 said:

When it failed, it lurched it's way 1/2 way up then retracted.  I ended up pulling the breaker since having one up is a no-no per the manual.  The other day I was looking at the left one with the switch pushed by accident and I could hear the motor? trying to engage the SB itself, but it wasn't moving.  Hopefully, your solution will fix it.  Before I bought her, she'd been sitting out for almost 2 years in the NE waiting for parts from Mooney leading probably to this and some heavily oxidized paint.  The SB's worked fine on the test flight, of course....

I’ve had had mine fail with one up and one down. There is plenty of rudder and aileron to counteract it. It is not the end of the world. You can still fly the plane.

[Fly Boomer]

17 hours ago, Jetpilot86 said:

Well, I'm just dense enough to have assumed Isabel was Mrs. Goyer.  Clearly I'm asleep, or is it not woke? <shrugs>

Remarkably difficult to find anything on the Internet about Goyer's journey.  As noted, apparently both Goyers are the same person.  Regarding the word "woke", it's just one of many words my kids use that I don't understand.  This explainer cleared it up for me:

https://youtu.be/sUeyWt6TKj0

 

[Jetpilot86]

On 1/6/2024 at 11:48 PM, N201MKTurbo said:

I’ve had had mine fail with one up and one down. There is plenty of rudder and aileron to counteract it. It is not the end of the world. You can still fly the plane.

Ya, I tried it once before I read the POH and found the restriction, would make for an entertaining approach to mins...

[N201MKTurbo]

On 1/6/2024 at 6:37 PM, LANCECASPER said:

This is something that is missed on almost every annual. The Instructions for continued airworthiness on the speed brakes say that the cartridge needs to come out (not difficult) and that the worm drive (not the clutch) needs to be lubricated with Aeroshell 22 every year (do NOT use any spray lubricant any where near the speed brakes). When the grease gets old and hard the mechanism becomes very slow until it fails. Cleaning it out and re-greasing with Aeroshell 22 and exercising the brakes will quiet them down and often get you many more years of service. 

Just did mine last week.

[Hank]

19 hours ago, Fly Boomer said:

Remarkably difficult to find anything on the Internet about Goyer's journey.  As noted, apparently both Goyers are the same person.  Regarding the word "woke", it's just one of many words my kids use that I don't understand.  This explainer cleared it up for me:

https://youtu.be/sUeyWt6TKj0

 

I had no idea that Robert Goyer us no more . . . . . I do remember seeing his name on many articles and several magazines.

Any more than that doesn't belong here.

[Hank]

On 1/6/2024 at 2:55 PM, ZuluZulu said:

Lance, I like you, and I hope deadnaming her was an honest mistake and not trolling for a political argument, given the name of the author on the page you linked is clearly Isabel Goyer, not Robert. To use that name and pronoun that aren’t even on the article instead seems like it might be intentional. She’s made her preference clear for quite some time now. If this was just a mistake, then accept my apologies.

But if not, haven’t we all argued about this enough now? Let’s leave this pointless complaining that trans people exist back in 2023. Happy 2024 to everyone and respect to all. Yes, all, even those some of you may not like. We’re all in this together. 

/flame suit on

Yes, let's leave this off of MooneySpace, a place we come to talk about our fantastic airplanes and get away from inane political commentary that has spilled over into so many aspects of our daily lives thenlast several years!

[Danb]

In fairness Lance didn’t start anything political, just mentioned an article regarding our aircraft.

[Hank]

12 minutes ago, Danb said:

In fairness Lance didn’t start anything political, just mentioned an article regarding our aircraft.

True. Then he was beat over the head with political correctness from something that most of us didn't know about. That's the part that needs to stay away from here.