Speed brakes for landing

[midlifeflyer]

Since this is what prompted my question, I thought I'd toss in a quick update. 

I had a chance to check out in an Ovation yesterday and got to play with the speed brakes. Very impressive. Thanks for all the advice here.

[jlunseth]

For those who were concerned about structural integrity at Vne,  I have done a prolonged dive at Vne with the brakes deployed with no issues.  Well, let's say "at or around," I was concerned about not exceeding Vne, but more concerned about keeping the engine alive and getting to the airport than speed control.  I have Precise Flights if that makes a difference.

Edited February 19, 2017 by jlunseth

[gsengle]

For those who were concerned about structural integrity at Vne,  I have done a prolonged dive at Vne with the brakes deployed with no issues.  Well, let's say "at or around," I was concerned about not exceeding Vne, but more concerned about keeping the engine alive and getting to the airport that speed control.  I have Precise Flights if that makes a difference.

Of course certification standards give a margin beyond Vne. Often the issue beyond that speed isn't structure, it's control surface flutter. Flutter is very bad and increases with true airspeed I believe....


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[donkaye]

3 minutes ago, gsengle said:

 

Of course certification standards give a margin beyond Vne. Often the issue beyond that speed isn't structure, it's control surface flutter. Flutter is very bad and increases with true airspeed I believe....


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From experience I have found that Speed brakes should be used in the manner I described in the writeup on my website.

[jlunseth]

22 minutes ago, gsengle said:

 

Of course certification standards give a margin beyond Vne. Often the issue beyond that speed isn't structure, it's control surface flutter. Flutter is very bad and increases with true airspeed I believe....


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Yes, I agree, flutter is the issue at Vne.  I was just responding to a couple of posters in this thread who were concerned about the structural integrity of the brakes at Vne.  Don't be.  On the other hand, I am not recommending going out and doing any Vne dives anytime soon either, mine was a declared emergency where you use everything you have to get down safely, which we did.  I am just providing a data point.

[M016576]

23 minutes ago, donkaye said:

From experience I have found that Speed brakes should be used in the manner I described in the writeup on my website.

I 100% agree with don's assessment.  Moreover- the guidance he posted is applicable to any aircraft that is equipped with speed brakes.

the key to speed brakes is to remember- that any time you deploy them, you are consciously degrading the efficiency of your aircraft.  There are circumstances outside of your own control that may dictate their use... but if you think ahead enough and stay ahead of the aircraft enough... and ATC doesn't paint you into a corner- you should be able to fly more efficiently without them.

just my opinion.

 

[carusoam]

If you want to go down now... the combination of speed brakes and wheels down is a powerful mix of air resistance.  Limitations are important for putting the gear down and the gear down speed should be considered if you intend to use the plane again...

In this case efficiency is the opposite of what you are looking for.  Descent rate is very high.  In a few minutes the ground will be closing in...

This would be the E-ticket ride if it is a real emergency...

Part of transition training.  I got to explore this corner of the Mooney envelope.

Best regards,

-a-

 

Edited February 19, 2017 by carusoam

[gsengle]

Yep to go down fast, drop the gear put out the brakes and dive in a 45 degree bank and go to the max gear extended speed.

 

 

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[Bennett]

Yep to go down fast, drop the gear put out the brakes and dive in a 45 degree bank and go to the max gear extended speed.
 
 
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That truly works! Did that in an emergency descent from FL230. I used the commercial spiral technique in which my indicated airspeed never exceeded 100 knots, and so I could also use full flaps, and a bit more bank angle. The VSI only went to 2000' /min, but by time I was closer to 3000'/min. Obviously it all worked out OK. Don, as always, offers good advice, but I still stick to my use of speed brakes the way I use them. "Your results may differ".


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[jlunseth]

Thank you for your suggestions, but actually there isn't a "best," there are two methods.  Gear down, brakes deployed is the "least distance, fastest drop" method.  Clean and high speed is the "most distance, most speed" method.  My on-the-spot alternative was the clean but brakes deployed and high speed method.  The brakes were used to keep speed from exceeding Vne.  

A knowledgeable pilot should know the alternatives.  If you are trying to get to the ground as soon as possible, the "gear out" method is the right choice, say, to make a near landing field.  Trying to get under an IMC deck and over to a 20 mile distant airport from 19k with a dying engine, the "clean, brakes, high speed method" is the better choice.  Trying to blow out an engine fire ( which is not what I was doing), one might choose the "high speed, clean" method.  

We made a power off landing on the tarmac, between the crash trucks.  The pilot, passenger, aircraft, and engine all survived.  So I appreciate the suggestion, but am very comfortable with the choices in the circumstances.  

As I said, it was meant as a data point.  The brakes don't tear out of the wings at Vne.

Edited February 20, 2017 by jlunseth

[M20F-1968]

I have experimented with speed brakes with landing on my F model.  I have the precise flight electric versions. 

Some of my best landing have been made with speed brakes out for the full final approach or from the FAF if IFR.  They do seem to be helpful in crosswind landings.

The plane feels heavier with speed brakes, gear and flaps out (I believe wing loading in increased) allowing (and necessitating) additional power to fly the same approach profile than without speed brakes.  The control surfaces are more responsive and the plane is more stable.  I agree with Don Kaye, I would not put them out at the last 100 feet above the ground.  They work well in a stabilized approach when factored in to configuring the airplane for the approach.  The airplane will climb with them out (albeit with more power).

I do not use them on all landings.  When crosswinds and gusts are less of a problem, fly the airplane conventionally without them.  But, if you want to carry more power for stability into the flair, they are a good option.

John Breda

[floridaflyer]

I never used speed brakes in my F because they made no difference. I'm almost always IFR in the Rocket and use them to slow down or drop down (or both depending on ATC) and I always land with them to reduce ground effect. Also it makes you look like a bad ass to the Airbus holding short. 

[Robert C.]

On 1/29/2017 at 9:56 AM, Rszent said:

Generally I use the speed brakes to land and leave them on all the way down to the runway,, they do very little below 90 knots but do help in the float. My base airport has a hill with a obstacle clearence light center line of the runway on 1/2 mile final,,some have accidently found it at night and crashed,, thats another story....so with a steeper decent thease birds dont hesitate to pick up speed so yes I use them..

Danbury?

[fuellevel]

I was in a Mooney at Vd with brakes extended for certification testing. Flutter was what we were looking for either in the wing or tail. Pointed at a ridiculous angle with power applied - rip hinges and chute strapped to my backside


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[carusoam]

Scott,

That sounds pretty interesting...

Was this related to fuel level instrument testing?

Best regards,

-a-

[Little Dipper]

On ‎1‎/‎30‎/‎2017 at 3:43 PM, BradB said:

if you want an idea of what the speed brakes do to airflow, put them up in the rain and look at the water flow. 

I have to take a look at that in the rain.   One thing for certain is never to use them in ice.   From experience I learned it doesn't take much ice for them not to retract.        My preference is to only use the speed brakes on short field and crosswind landings.   I use the speed brakes primarily for gradual descents without the need to change power settings.

[carusoam]

Somebody posted a video around here of the speed brakes operating in rain... the airflow disruption was much larger than I had expected...

Best regards,

-a-

[gsxrpilot]

 

[Pissed'Ole-Pete]

Is anyone on this thread glider rated?

[Robert C.]

2 hours ago, Pissed'Ole-Pete said:

Is anyone on this thread glider rated?

Spent 7 years in them

(not current though)

[Pissed'Ole-Pete]

Is speedbrake use on powered aircraft that different than in gliders?

 

[carusoam]

Yes...

Speed brakes get used a lot and are more effective at cutting lift in a glider...thus allowing a glider to come in with more reserved energy and dump it when the field is made...

Speed brakes in Mooneys are more of an adjustment than a plan A.  Plan A uses as much of the energy available to get from point A to point B as quickly as possible.  Using the brakes is somewhat anti-efficiency when flying a Mooney.  Come in too high or too fast, the brakes get used to adjust the flight characteristics...

We adjust power to make the field, and cut the throttle when it is time to land.

The glider uses excess altitude to make the field, and cuts the lift when its time to land.

They work the same. But the uses and scale are different.

PP thoughts only, not a glider pilot...

Best regards,

-a-

[Pissed'Ole-Pete]

1 hour ago, carusoam said:

Yes...

Speed brakes get used a lot and are more effective at cutting lift in a glider...thus allowing a glider to come in with more reserved energy and dump it when the field is made...

Speed brakes in Mooneys are more of an adjustment than a plan A.  Plan A uses as much of the energy available to get from point A to point B as quickly as possible.  Using the brakes is somewhat anti-efficiency when flying a Mooney.  Come in too high or too fast, the brakes get used to adjust the flight characteristics...

We adjust power to make the field, and cut the throttle when it is time to land.

The glider uses excess altitude to make the field, and cuts the lift when its time to land.

They work the same. But the uses and scale are different.

PP thoughts only, not a glider pilot...

Best regards,

-a-

Thanks, I am hearing, "same tool, Different order of magnitude"....  I probably have the same amount of flight time in Mooneys as I do in gliders, (which ain't a lot). The Mooney I flew was an exec, and was not fitted with speed brakes

[carusoam]

Somebody just reposted a video of speed brakes being used in a mooney in rain, today (last 24 hours).

It gives a nice visual explanation of the overall effect on airflow around the brakes.

They effectively eliminate a few square feet of the wing's lift capacity. Altering the AOA maintains the lift required, with a greatly increased air resistance...

Another difference of the mooney speed brake use compared to gliders....

Mooneys use them at high airspeeds, deployable up to Vne... great for slowing down to Gear operating speed, lower the gear...Descend at gear down speed, with the gear down and speed brakes deployed....the Vsi will be unwinding in the thousands of fpm...

Great for emergency descent...

They are less effective at approach speeds and aren't very noticeable during the landing phase...

gliders like to use them at slower speeds during the landing phase...

We have a couple of glider pilots around here as well. One that has tried to set records for distance and time...

We have a few threads on speed brakes. They come in a few varieties. Manual, vacuum, and electric... There is a set made by a different manufacturer, similar to a door...

PP thoughts only, not a CFI...

Best regards,

-a-

[fuellevel]

I was an owner at Precise Flight and left in 2010. that was pre - cise. Now my company is cise. Spelled CiES. You'll find I authored the installation document for the current speed brakes as well as the structural report . Overturning moment is tension on the skin which frankly at that speed isn't going anywhere.


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