Need for Speed brakes

[DonMuncy]

To avoid hijacking a thread:

In the Avionics forum, someone posted

"... and save my money for speed brakes"

 

My thoughts

My 231 has speed brakes, and I like them. For an emergency descent, they would be wonderful. When ATC gives you a late descent clearance, they are pretty nice. When I got my plane they were an almost "must have" spec.

However, after 17 years of ownership, I have to question whether I would pay for buying and installing them. Perhaps if I had already installed everything I wanted, and had money left over. But there are a lot of things that are higher on my need list.

What is the collective opinion of the group.

 

[gsengle]

Even in my long body, I think I could live without em. I used em more in the early days of ownership but now I just know how to plan descents better.... not a must have, but yes nice.


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[peevee]

Stock 231 I didn't use them much. Now I consider them necessary.

[Yetti]

All the mooneys have 2 very effective speed brakes under the wing.

[smccray]

Good thread.

J model here- I wouldn't spend the $ for speed breaks. In a slippery turbo it might be desirable in order to stay high longer, but in a NA plane- I descend at full throttle lean of peak at 500 ft per minute and I stay in the green.  If I need to increase the descent I reduce the throttle- no big deal. 

I don't have any exerience in a turbo or in an ovation cruising in the mid teens, but I would lean towards having speed breaks to get a 1000 fpm descent when solo so I can stay high (cool) longer. 

[carusoam]

When flying like an engineer by the numbers... not needed.

When flying like a human being... a comfort to have.

The older I get, the more human I am.

 

They would be difficult to buy based on their cost benefit ratio.  Much easier to appreciate when they came with the plane.

If you need a reason to add them...  Long Bodies are not approved(?) for full flap / Cross controlled activities near the ground.  The brakes can be used as a substitute.   (Depends on your finance administrator)

 

To witness their awesome power use them during a practice E-descent. Gear down, brakes out, accelerate to Vle...   (use proper technique of course)  it won't take very long to get to the ground...

Best regards,

-a-

 

[Piloto]

Speed brakes were nice to have on the days before GPS. But with GPS now you can get an accurate ETE that helps in determining your TOD (top of descent) or VSR (vertical speed required). Flaps and landing gear have a greater effect on slowing down a Mooney.

José

[Cruiser]

Mine are called "Descent rate control (electric)"

| EMERGENCY DESCENT PROCEDURE"]
In the event an emergency descent from high altitude is required, rates of descent of at least 3,000
feet per minute can be obtained in two different configurations:
(1) With landing gear and flaps retracted, an airspeed of 195 KIAS will be required for maximum rate of
descent.
(2) With the landing gear extended and flaps retracted an airspeed of 165 KIAS will also give approximately
the same rate of descent. At 165 KIAS and the gear extended, the angle of descent will be
greater, thus resulting in less horizontal distance traveled than a descent at 195 KIAS. Additionally,
descent at 165 KIAS will provide a smoother ride and less pilot work load.
THEREFORE; The following procedure is recommended for an emergency descent:
Power. ........................................................................................ RETARD INITIALLY
Airspeed . . . . . . . . . . . 140 KIAS
Landing Gear . . . . . . . . . . EXTEND
Airspeed. . . INCREASE T 0 165 KIAS after landing gear is extended.
Wing Flaps . . . . . . . . . . . UP
Airspeed . . . . . . . MAINTAIN 165 KIAS during descent.
Speedbrakes (If installed) . . . . . . . . EXTEND
Altitude . . . . . . . . . . AS DESIRED
Power During Descent . . . . . . . . AS REQUIRED
to maintain CHT 250 F (121 C) minimum.

[carusoam]

Interesting where they have the speed brakes in the order of things...

If you are in a rush to get down, slowing to gear operating speed may take a moment.  It may make sense to extend the brakes first because you can.  Start dissipating energy now while organizing the next steps.

Either way, The fully developed descent rate is quite large.

nice to see the CHT reference as well.  Since you are going to add the last piece of braking from the engine. Use the Jake brake...pushing the prop control full forwards will compress a lot of air in the cylinders using up more energy on your way to the ground...

Two interesting experiences.  Engine break-in flights, high power, low altitude.  And E-descent training.  Both Done with a CFI on board to not accidently over bake something...

Best regards,

-a-

Edited April 8, 2017 by carusoam

[carqwik]

On occasion, I've found ATC treats me like I've got a turbine and gives me ridiculous descent requests (usually crossing restrictions) which would be doable in a turbine but not in a piston.  So at times, the speed brakes can help meet ATC needs, other times "unable."

[Greg252AY]

I have used my speed brakes a couple times to make sure they work in my 252. Cant remember a time I have needed them yet in 300 hours of flying. I wouldnt pay any extra to have them. Maybe i am too cheap, figure i will use altitude  for speed or less fuel on the way down. 20" manifold keeps the engine warm enough on my plane

[carusoam]

Speed brakes are kind of anti-mooney devices...

- they don't increase airspeed.

- they don't increase efficiency.

Best regards,

-a-

[Guest Mike261]

Speed brakes are a great tool when you need them. I needed them often when i first got my plane. I rarely use them now, and i find myself saying oh yeah i have speed brakes if I'm high on an approach or slam dunked...worth it? for the neophyte...absolutely.

mike

 

[Guest Mike261]

12 minutes ago, carusoam said:

Speed brakes are kind of anti-mooney devices...

- they don't increase airspeed.

- they don't increase efficiency.

Best regards,

-a-

ok...so not to be contrarian, well yes to be contrarian.

they do increase cumulative airspeed...stay fast until closer to your destination and then deploy them and throw the nose over...go down but don't slow down, and no shock cooling if you ascribe to that sort

 of thing.

for efficiency see above, reclaim the energy invested in the climb at a higher airspeed.

mike

 

[carusoam]

Way to go Mike, mooney pilots are contrarians... 

use caution on the 3k'/min ear popping descents, passengers may not be comfortable...

Best regards,

-a-

[Bob - S50]

Don't have them.  Don't need them.  However, there are times they would be nice, but for me, that's only when terrain is a factor that prevents a long gradual descent.

After 20 years flying the DC9 I got pretty good at "unable".

At the airlines, if I used speed brakes it meant I had wasted gas (I could have come to idle sooner instead).  I especially feel the same way now that I'm paying for the gas.

[Greg_D]

52 minutes ago, carqwik said:

On occasion, I've found ATC treats me like I've got a turbine and gives me ridiculous descent requests (usually crossing restrictions) which would be doable in a turbine but not in a piston.  So at times, the speed brakes can help meet ATC needs, other times "unable."

I'm curious...what kind of descent crossing restriction would ATC give that a turbine aircraft could make but a Mooney couldn't?  Climbing would be a different story.

[peevee]

57 minutes ago, Greg_D said:

I'm curious...what kind of descent crossing restriction would ATC give that a turbine aircraft could make but a Mooney couldn't?  Climbing would be a different story.

3 or 4k a minute is really no big deal for a jet. 2k or 2.5k a minute seems pretty standard... Unless you're that dude doing 500fpm or less for no reason and you have an animal on your tail.

[PTK]

In my opinion speed brakes is one of those things that's very desirable when already installed on the airplane as opposed to putting out the expense.

I have only used mine a handful of times and are nice to have when needed.

I do agree with Anthony that speed brakes are anti-Mooney! For the huge increase in rate of descent they introduce equally huge amounts of drag. But the fact that we need them to re-introduce drag speaks to how really clean the Mooney is! It's a great feeling to be flying such a refined and perfected airplane!

 

[DMJones]

When I was shopping for a Mooney, they were on my list of "wants."  But the one I found and liked best didn't have them, and had long-range tanks which complicates the install.  So, I've gotten along without them.  I have to be honest, I've waited too long to start down a couple of times, but I managed to get the gear out, or went past the field a bit and then doubled back.  So, I've learned to live without them, and won't spend the money now to have them.

I also learned the "airline way" and have tried to avoid using them in the past and save the gas.  But modern airliners won't slow down without them, and modern arrivals sometimes require 2000'/min in the descent, so in the big jets they are now a way of life.  In a way, it's pleasant to fly the Mooney in a more "leisurely" fashion and avoid needing them.  My $.02...

[KSMooniac]

I'd rather save the expense and weight penalty...haven't felt like I needed them in 10 years of J ownership.

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[midlifeflyer]

45 minutes ago, KSMooniac said:

I'd rather save the expense and weight penalty...haven't felt like I needed them in 10 years of J ownership.

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Interesting perspective. According to Precise Flight, the installed weight of its Mooney speed brakes is 9 lbs. As I recently mentioned in a thread, I was introduced to an Ovation a few weeks ago. I've flown Cs and Js but this was my first time with both an Ovation and with speed brakes. The thing that struck me most about the Ovation were the many weight penalties - speed brakes, icing fluid, fairly large fuel tanks - and the resulting tiny full fuel payload. 

So, FWIW from a speed brake newbie: Great concept for the end of the "keep your speed up" approach to get down to gear speed. And also for getting down without having to reduce power precipitously when ATC keeps one high for an extended period. Other than those situations, I don't see too much need for them, weight issues aside. 

[gsengle]

It's true, but the tiny remaining useful load is largely just about flexibility. How many GA aircraft can stay aloft 7 hours? You don't have to put 100 gallons on board, or fill the TKS tank... I wouldn't penalize the Ovation or other long bodies for granting you such amazing flexibility.


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[RobertGary1]

I just slip instead. For the approach into SMO I'll slip with full rudder in the clouds with gear and flaps out to make the MDA before passing the airport. 

 

-Robert

[Shadrach]

1 hour ago, RobertGary1 said:

I just slip instead. For the approach into SMO I'll slip with full rudder in the clouds with gear and flaps out to make the MDA before passing the airport. 

 

-Robert

I've been told that slips in a Mooney demonstrate poor airmanship. Real pilots use speed brakes.