Need for Speed brakes

[carusoam]

Nice flush mounted color screen, Byron.

Best regards,

-a-

[M20F]

9 hours ago, Greg_D said:

So, how quickly do you advance the throttle on takeoff when going from near idle to full power?  How would reducing the throttle at the same rate and by the same magnitude while at cruise power and altitude be any different?

As I noted in my original post, topic of contention.  

[mike_elliott]

9 hours ago, gsxrpilot said:

BTW... I was in the "no speed brakes" camp as long as I flew an M20C. But now that I have a 252, I gotta say, I love my speed brakes. In fact, I'd have loved to have them in the C, now that I've gotten to know them.

Speed brakes are a tool in your tool box to help a messed up situation, intentional or unintentional, your doing or complying with the wish of others. In other words, they are nice to have when you need them. I very seldom use them for descents or approaches, but find them nice to help keep a plane planted on the goat farm runway known as Hidden lake airpark. Older C models that had a lower gear speed they would be more useful than on a newer J.

[Immelman]

Not necessary in a piston airplane. You can always do a 360, or request a delay vector. How many of those does it take to pay for installing and maintaining speed brakes?

Useful in a jet with an awesome glide ratio, but still somewhat poor form to use them all the time.

[Guest Mike261]

23 hours ago, Shadrach said:

Yea see, that's the ticket...adding drag inducing devices to your approach profile is more efficient because it helps reclaim the energy used for climb in the decent see...sure...that's the ticket...

There is a principal called the conservation of energy that contradicts what you're suggesting. You have a fixed amount of potential energy at the TOD, any parasitic drag introduced during descent diverts that energy away from the work of getting you to your destination.

That's like putting bigger disc brakes on your car so that you can hold your speed until just before the intersection and brake hard. It is not efficient at all...

Excellent demonstration of how humans can articulate a rationalization that is contrary to well understood principals of physics.  

excellent demonstration of spin...

thats not what i said at all.

I spoke the efficiency of higher speed for a longer time. All i talked of was higher speed, using the energy to gain time by inducing drag for a quicker descent thats easier on the engine.

you jumped on it, spun it and turned it into a thinly veiled insult.

 

[Guest Mike261]

oh...and by the way putting bigger disc brakes on cars so you can brake hard just before you hit a corner is quite an efficient use of time as evidenced by how often its used in professional racing. lots of energy turned to heat, but winning the race is the idea. spin...its awesome

 

 

 

[M016576]

Not worth the weight penalty, imo.  Plenty of other options to get you slowed down and descended.

[donkaye]

My take on the use of Speed Brakes is discussed in the following article I wrote. While not "must have" for everyone, they are "must have" for me.  Since I am based in a Class C Airspace, I am often asked to keep my speed up as long as practical to accommodate arriving jet traffic.  I maintain 160-170 KTS until 5 miles out, then use the speed breaks for quick deceleration.  Coming into the pattern, normally I will come in at that same speed and wait till I'm about to turn base before slowing.  Knowing your airplane well (your rate of slow down) is necessary for this to work well.  Basically, I'm using a constant slope variable airspeed approach, making sure I'm flaring at about 70 knots depending on weight.  That is NOT the way I teach, which is a constant slope constant airspeed approach.  The former technique requires a higher skill level that can be achieved through practice by flying your airplane a lot.

Bottom line, speed brakes, while another item in your bag of tricks, when used as discussed, bring much more utility and efficiency to flying your airplane.

Speed Brake Use.pdf

[M20F]

2 hours ago, M016576 said:

Not worth the weight penalty, imo.  Plenty of other options to get you slowed down and descended.

The joys of older Mooneys is 1000+ lbs of useful load :-)

[M016576]

1 hour ago, donkaye said:

 

Bottom line, speed brakes, while another item in your bag of tricks, when used as discussed, bring much more utility and efficiency to flying your airplane.

Speed Brake Use.pdf

I would disagree with "much more utility and efficiency."  

Maybe a "little utility."

When I calculate the difference in using speed brakes to drive in to 5nm vs slowing at 10-15nm and deploying the gear, the difference is under a minute of time. Over the course of 2 hours of flight I don't classify that as "much more utility and efficiency."  Penalty vectors and the "slam dunk" are the other arguments I hear for wanting speedbrakes.  Both of which can be mitigated by forward thinking through the approach/ entry to the field.  

I feel like we've discussed this before.  I do tend to agree with your PDF, for what that's worth.  Any time a pilot deploys speed brakes, they are intentionally causing an inefficiency.  They are adding drag (or disrupting lift, similar net effect once stabilized).  So that in itself must be offset by a substantial gain in efficiency elsewhere to make up for the disruption.  

Bottom line- trick / tool for the box.  Not necessary to me in a GA single where you've got a huge speedbrake on the front of the plane, and three smaller ones that come out the bottom.  To me, I'd rather have the useful load.

all just my humble opinion.

Edited April 9, 2017 by M016576

[JohnB]

I use my speed brakes quite a bit in busy airspaces. I'm often asked to best speed as long as practical on approaches with lots of jet traffic, so going from 160+ to landing speed while still descending is easy to do with speed brakes, if I didn't, I would need to start slowing down well before the final approach fix which would make the controllers less gleeful. Other than that, I could probably not use them. Oh in turbulence to slow down quickly they're also helpful.

[M016576]

2 minutes ago, JohnB said:

I use my speed brakes quite a bit in busy airspaces. I'm often asked to best speed as long as practical on approaches with lots of jet traffic, so going from 160+ to landing speed while still descending is easy to do with speed brakes, if I didn't, I would need to start slowing down well before the final approach fix which would make the controllers less gleeful. Other than that, I could probably not use them. Oh in turbulence to slow down quickly they're also helpful.

I understand this argument, but really while it "feels" like you are helping the situation, and you may be, standard IFR separation *should* cover you in the piston aircraft.  I put stars there because, sometimes, you're right- the sequence is set too tight by the controller.  Ultimately, though, there are other ways to slow down that are similar in effect, and/or, "unable."  And the difference in time airborne is negligible.  Again, all this is just my subjective option- some guys love them- and that's totally cool- I just don't think they are necessary.  But I do see your point, and if you see this situation often (I don't), then maybe you do need them.

I am not under a B/C umbrella at my home field, so take that with a grain of salt.  I do fly the missile into these airspaces on a regular basis, and I've never had a problem controlling descent  rates or speeds.  I have received a slam dunk once going into Henderson: 13k within 10nm of the field, but I recognized the situation, and configured to be in a long descent all the way down and around to short final.  Speed brakes would have been ok for that scenario- but I was still able to make the approach happen without penalty vectors.  

 Observing other pilots, in different types of aircraft, I have witnessed a disturbing trend, though... I see pilots deploy speed brakes, then add power.  When I've pointed this out, most of the time, they don't realize they've done that!  I do get the impulse there, too: you're going too fast, or need a descent- you deploy the boards.  You start picking up too much rate of descent, or the rate of speed loss is too great.  You add power.  There are times, where, if you've slowed down, though, or just let the aircraft stabilize, you might find that while it's not as "quick" to reach your target FPM descent rate, you'll get there without the speed brakes nonetheless.

they certainly have their place, as you know, and as Don's PDF explains.  I just don't, personally, find them necessary based on the weight penalty and cost of installation they incur.  But, if you've already got them..., might as well use them!

[gsxrpilot]

@M016576 I'll agree with you that I wouldn't spend the money to install aftermarket speed brakes.  But at the same time, I wouldn't buy a turbo Mooney that didn't come with them. 

And BTW I just can't disagree with @donkaye. He's got more time in more Mooney's than half of everyone on this forum put together.

[donkaye]

No doubt, you really don't need them in the shorter body Mooneys.  They don't go that fast.  But, when in the shorter body Mooneys when teaching, I've many times been vectored out of the sequence going into San jose and vectored around until the line of 3 or 4 jets lands before being vectored back onto the the ILS.  Time and fuel are wasted in those circumstances.  Likewise, when I say I can give them 170 knots on final, they'll stick me in the sequence--no problem.

Yes, they weigh 9 pounds.  In my opinion it's worth going on a diet if need be to gain the benefit speed brakes provide.  

But over the past several years I've taken a different perspective on the financial aspect of airplane ownership. If I want it, I get it.  For example, although my old style braking system worked just fine for 22 years, I decided I wanted the newer braking system.  The price had doubled since the last time I had looked.  I did it anyway, and love the new system.  I understand that might not apply to others.  

[gsxrpilot]

1 minute ago, donkaye said:

But over the past several years I've taken a different perspective on the financial aspect of airplane ownership. If I want it, I get it.  

The pull of the force is strong, Obi-Wan.  Try as I might, I can't seem to resist. I bought my 252 with the intent to clean out the panel, KNS80, ADF, etc. I might have gotten a bit carried away.

[Danb]

Paul the left foot goes in front of the right, we basically failed the finance course when buying our awesome planes, making them better was the next obvious step regardless of our budget. 

[donkaye]

1 hour ago, gsxrpilot said:

@M016576

And BTW I just can't disagree with @donkaye. He's got more time in more Mooney's than half of everyone on this forum put together.

For anyone interested:

Don Kaye Mooney, Instructor, and Total Flight Time.pdf

[Danb]

What's the purpose?

[Andy95W]

Don- you need more M20C time.

[gsengle]

I don't see and fixed gear Mooney time either...


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[donkaye]

1 hour ago, Danb said:

What's the purpose?

None...or however anyone may want to use that experience.

[donkaye]

55 minutes ago, Andy95W said:

Don- you need more M20C time.

After 8,900 hours of Mooney time, flying and training people in the C Model is like training someone in a C150.

[donkaye]

47 minutes ago, gsengle said:

I don't see and fixed gear Mooney time either...


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That just shows how many of them are out there.

[Hank]

6 minutes ago, donkaye said:

That just shows how many of them are out there.

There are still three (3) unmodified M20-D Mooney Masters out there . . . . 

P.S.--I love my C and find it to be light years ahead of the more recent C172s that I trained in for my PPL. My Mooney was the perfect first airplane to buy 6 weeks after my PPL checkride. Now, it's part of the family.

No speed brakes other than the big 3-bladed one on the nose. With 120 mph gear speed, they just don't work well. But rock into 45° bank and the emergency descent will be 2000-2500 fpm. Amazing!

Edited April 10, 2017 by Hank

[Piloto]

With the pilot relief tube there is no need for speed brakes to rush down for a restroom. No messy bottles to empty or fat gel bags to dispose. You just relax and enjoy the flight.

José