Speed Brakes and piloting technique

flyingcheesehead

flyingcheesehead

Touchdown! Greaser!
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iMooniac
Here's another one for something that's new to me with the Mooney...

I've always thought that speed brakes are kind of a crutch and one should avoid using them if at all possible, not to mention that you are losing a tad of efficiency by giving up potential energy to pure drag.

However, I'm finding it difficult to NOT use them in the Mooney. The darn thing just won't slow down!

Here's how I'm doing normal descents: I generally cruise at WOT and 2200-2300 RPM up high, no more than 23" MP if I'm low enough to pull more, and I get easily 140 KIAS pretty much anywhere below 10,000 feet. I plan my descents as follows: Let's say I'm getting 170 knots groundspeed. I figure an extra 10 knots for the descent, so 180 knots or 3 miles per minute. At 500 fpm, that's 6 miles per 1000 feet, and whatever amount of altitude I have to lose to the airport, that's how far out I do it (ie cruise at 8000, field elevation 1000, 7000 feet to descend at 6 miles per 1000 means I start the descent 42 miles out. (You'd think that would be enough!)

So, at the top of the descent I'll reduce throttle to 20" MP and begin a 500 fpm descent. This usually results in about 160 KIAS. After a couple of minutes, I'll pull back to 17" MP, which results in basically no slowdown. After a few more minutes, I'll pull back to 14" MP, which slows me down to maybe 155 KIAS.

The problem: If I pull the throttle to less than 14" MP, the gear warning horn goes off even though I'm still well above gear extension speed, which is 140 KIAS. I either have to level off and wait a while to get the gear out, or I have to use the speed brakes to get me down to 140 KIAS while continuing the descent. Even with the gear out, I usually leave them out to help get down to flap speed (110 KIAS), and then to landing speed (75 KIAS). In fact, I've been leaving them out for the entire approach a lot of the time (Except in the unlikely event that I get all the drag out with little enough power that I start to get slow), only stowing them as I exit the runway.

FWIW, I'm using 1500 RPM (very low MP) as my power setting on final with gear, flaps, AND speed brakes hanging out. That gives me a nice 3-4 degree approach angle.

The ONLY time I've managed to avoid using the speed brakes for an entire approach was when I flew Adam and Alon into OSH - 135 KIAS, 1500 AGL at Ripon (10 miles out), dropped the gear and descended to 1000 AGL at Fisk (5 miles out), dropped the flaps when I could and made it without the speed brakes. Maybe I should be using this technique all the time, but I dislike being so low so far out.

Maybe I'm also just being too impatient and wanting to get in without having to slow down so much so far away. Maybe I've spent too much time with the drag-o-matic 182 screaming nearly into the pattern at 130 knots and putting on the brakes... Heck, even the Diamond Star seems draggy in comparison to the Mooney!

So, what say you folks - Is making use of speed brakes sloppy piloting technique, or should I just get over it and use all the tools I have available?
 
Speed brakes are a great tool to be used in a variety of situations, Kent. I wish we had them in the Mooney I fly. The mooney wing loves to fly and doesn't slow quickly.
 
Sloppy? Heck no, they are an excellent tool. I wish I had them, but at least I have a 154 knot gear speed.

It is indeed tough to go down without getting into the yellow right quick, and in bu,pay air, that is not good.
 
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flyingcheesehead said:
So, what say you folks - Is making use of speed brakes sloppy piloting technique, or should I just get over it and use all the tools I have available?
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Not sloppy at all - that's what they're there for. I probably have about 10 hours in a Mooney 201, so I'm no Mooney expert, although for some reason I'm qualified to evaluate them :) I suspect somewhere below about 15" you'll hear the sound of the prop driving the engine. I generally avoid operating in that zone if I can avoid it. Mostly because it just seems sloppy.

More about props driving engines:
http://www.avweb.com/news/pelican/186778-1.html

It's amazing how many Mooney or Bonanza drivers I've seen just absolutely slam the throttle in and out for no real obvious reasons. Given how expensive the engines are in some of these HP airplanes..I'd try to be smooth.


The thing is..you have the following choices:

1.) Try to do everything even slower, not very efficient
2.) Level off for awhile to lose energy. Once again, this takes time
3.) Deploy the speed brakes

There is nothing wrong with doing option 3. I typically try and reduce power slowly over X amount of time while trying to time things to where I'll be just coming up on gear speed a few miles from the airport. If speed brakes allow you to do that more precisely, go for it.
 
Speed brakes are a tool: use them if you need them. It's best to plan ahead so that one doesn't need to use them, however.

It's hard to go down and slow down.

Reduce your descent or stop it if necessary.

Use the speed brakes when you need to.
 
I always used the boards up a little to keep the N2 up so the spool up time would be minimized . . .

In a slick airplane you need to plan the descent a little bit - and sometimes ATC will slam dunk -

Next time you are flying commercial into a hub take a look at how often the boards come out . . . they are tool - not a crutch.
 
Actually, the thing I like most about the speed brakes: It takes me from level flight to a nice 500fpm descent with no trim, airspeed, or power changes. Done descending, put 'em down and you're level again. Easy peasy lemon squeezy.

But I guess I'm starting to feel better about using 'em...
 
flyingcheesehead said:
Actually, the thing I like most about the speed brakes: It takes me from level flight to a nice 500fpm descent with no trim, airspeed, or power changes. Done descending, put 'em down and you're level again. Easy peasy lemon squeezy.

But I guess I'm starting to feel better about using 'em...
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In the A36 Bonanza I used to fly, extending the speed brakes slowed you to gear speed. Once the gear was extended, that slowed you to flaps full speed. It worked out quite nicely.
 
I'd just say, on that great airplane, your Uncle ordered them for a reason. Mooneys are slippery.
 
> crutch

Um, not. In the Bo, pressing the button in cruise gave me a 500 FPM descent without fussing with trim or power. Love'd them.
 
I've got a couple hundred hours in Mooneys, both with and without speedbrakes. Like the DA40 they can be difficult to slow down particularly if you want to slow down and go down at the same time... Mooneys are BAD at that <wink>.

I was taught that they're a great tool but one does need to be able to work without them - I've had asymmetric deployments and complete failure to deploy a time or two.

Without them, I have to plan on level flight for a segment to decelerate to either the gear or approach flap speed, and then going down isn't so bad, though depending on the model you have to be careful of speed in the descent with only the flaps.

With them, it's easy to stay clean and use them as necessary to modulate your descent.

At busy airports, on a Mooney with brakes, it's possible to fly the final visual approach at 140, and on short final put out the brakes, maintain altitude for a bit while the speed drops, then dump the gear and flaps and be at 75 or so over the numbers. On an instrument approach you can do a similar thing on the initial approach to maybe a half-mile short of the FAF, and slow to a good approach speed by the FAF as you put out the draggy stuff and then fly a nice and stable final approach segment.

Of course, if the brakes don't work and you're depending on them for whatever application of drag you need, you get to go around and try again.

So... My advice is to practice flying the pattern and such without the brakes until you get your speed control to be natural. Then start using the brakes to go faster on your flight segments up to final approach or pattern entry.
 
Seems like initiating the descent earlier would be the ticket to landing sans speed brakes. That said, I'd use them if I had them. Thing is, my airplane is one giant speed brake, so I really don't have to worry about it.

I really need a rich uber-elderly relative to expire and leave me an airplane like this, so I can have such problems.
 
They're there for a reason, use them! I'd find it much preferable to the scooting in low and then dumping everything in on final. Curious though, why pull the prop so far back on final?
 
Is an autopilot only used by sloppy pilots?

Use 'em! Just be proficient with out them as well.
 
Arbiter419 said:
They're there for a reason, use them! I'd find it much preferable to the scooting in low and then dumping everything in on final. Curious though, why pull the prop so far back on final?
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I don't think he pulls the prop back, 1500 is about right for low power operation just based on throttle position.
 
Arbiter419 said:
They're there for a reason, use them! I'd find it much preferable to the scooting in low and then dumping everything in on final. Curious though, why pull the prop so far back on final?
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I'm not pulling the prop back...

Skylane81E said:
I don't think he pulls the prop back, 1500 is about right for low power operation just based on throttle position.
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Bingo. MP is low enough that the prop is below the governing range and sitting at flat pitch. It's very little power, but I still need all the drag out to keep it coming down.
 
I've got 500 hours in my M20J with speedbrakes. It will slow down to gear speed in about 30 seconds after leveling off with the throttle advanced just enough to avoid triggering the gear horn.
 
Crutch? No way. Use them if you have them- I'd love to have them on my J.

That said, I had speed brakes on my want list not need list when shopping and the plane I bought doesn't have speed brakes. I've found that I don't have too much difficulty slowing the plane down. Level off, get below 140 kts (which may be easier in a J than an ovation) and with the gear down there's enough drag that the slippery reputation of the plane becomes a non-issue.
 
Royski said:
I've got 500 hours in my M20J with speedbrakes. It will slow down to gear speed in about 30 seconds after leveling off with the throttle advanced just enough to avoid triggering the gear horn.
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So, maybe add two miles to my top-of-descent calculation then...

Do you use your speed brakes regularly, or do you prefer the level-off?
 
I did my CFI in M20J with no speed breaks :) I have never had so much fun in any other aircraft doing power off 180s :lol:
 
flyingcheesehead said:
Do you use your speed brakes regularly, or do you prefer the level-off?
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I hardly ever use them anymore as I don't like to waste energy, but they were handy for transitioning to the plane out of a 172. They were awfully handy once when I couldn't get cleared for a timely descent out of ATC while IFR and also helped with the power-off 180 landing for the commercial rating.
 
Royski said:
I hardly ever use them anymore as I don't like to waste energy, but they were handy for transitioning to the plane out of a 172. They were awfully handy once when I couldn't get cleared for a timely descent out of ATC while IFR and also helped with the power-off 180 landing for the commercial rating.
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Yeah, that's kind of how I feel re: energy. I guess I'll add a couple miles to my TOD and see how that works. Of course, they're always there when needed, and they're still awfully nice for that no-reconfiguration 500fpm temporary descent too.
 
The other way not to use speed brakes is to pay attention to your descents at 500fpm - determine your AVERAGE speed in the descent at 15" MAP or so as well as 20" - and once you know your average speed you can then determine your time - from 7500 or 8500 or wherever - then once you have your time you know your needed descent rate. Once you know both of those you look on your GPD for Time to Destination and THATS when you start your descent . . . maybe 30 seconds earlier to give you time to level off - drop the gear and complete the configuration to land . .
 
I have over 3,000hrs in all the Mooney models and rarely had to use the speed brakes unless ATC requires a quick descent. In fact my M20J has no speed brakes and never had a need for them. Other bigger and faster airplane I have flown neither have them (spoilers). For my plane I use the TOD (Top of Descent) feature of my Aera 560 (programmed for 600fpm descent) to start my descent. The 560 will give you the TOD and required vertical speed (RVS) to achieve your final altitude. I throttle back to about 15"MP before starting descent and try to maintain no higher than 150KIA. It is always a good idea to slow down on your descent because you may encounter unexpected turbulence at the lower altitudes. If you are coming down through icing conditions do not deploy the speed brakes even if you have TKS, they will freeze and not retract. The only time I found the speed brakes useful is for not planned descent rates as those ask by ATC.

José
 
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