Speed Control

[Wheelsnwhings]

I’m new to Mooneys, having bought my first only weeks ago. One issue I keep having is speed control. Are there any tricks y’all have to slowing the things down while descending or should I just plan for a 300fpm decent at all times?

[carusoam]

Welcome to the world of Aviation WNW!

Did you know…

Descending from the flight levels at 300fpm could take all day… 

Even when driving at highway speeds… hitting the brakes can be OK at certain times… or maybe you need to lift the throttle….?

 

There are 20+ different models of Mooneys… M20, A, B, C, D….

Some have the choice of three different prop configurations… Two, three, and Four blades….

many don’t have shock cooling issues…

the plane doesn’t always drive the prop…

 

With all that power… and efficiency… comes some responsibility…

Learning about your plane… and unlearning some bad habits or OWTs may be helpful…

 

Some of these things are learned by Transition Training… did you get any?

Some are learned in conversations around here everyday…

Some comes from classic aviation 101…

The challenge in helping somebody get to their next level… is determining where they are starting from…

Why are you using 300fpm?

That is something I may use around the traffic pattern…

In an E-descent I may use 6kfpm…

 

It all depends…

Fill in some additional details, narrow things down…

Or it could be the middle of the night… or early Sunday morning…

 

Are you familiar with Vne?

Are you familiar with maneuvering speed?

Do you know that pulling the throttle out can increase your descent rate?

Mooneys have soooo many tools in the tool box… select the right tool for the situation….

Remember not all flights are the same…

Start like many of the other MSers… by filling in some data in your avatar area… are you flying an Acclaim, an M20A, or an M20J?

Do you like speed, efficiency, and safety?

If efficiency is your thing…. While speeding down the descent… you start bouncing off various limitations like Vna and Vne… use the other controls that you have…

PP thoughts only, not a CFI…

Best regards,

-a-

[Hank]

Welcome @Wheelsnwhings! Like Anthony above, I'm just a PPL, but I've been flying my Mooney for 15 years now.

Descending is simple--I just push the yoke for 500 fpm and spin the trim wheel for hands off. As I come down, I periodically walk the throttle backwards and the mixture forwards to re-establish whatever my cruise settings were for MP and EGT.

Yes, airspeed builds rapidly, up to 165-170 mph, still in the green for my C model. This makes up for the slow climb to altitude.

I like to level off at TPA a couple or three miles before the airport and let speed bleed off. If it won't slow into the white arc by itself, then I reduce throttle some more with the goal of putting out Takeoff Flaps no later than pattern entry.

Instrument approaches are similar but obviously you must stop descent somewhat higher and reset power for that altitude from the power settings you developed. 

Coming from the Cessna world where I could overfly my destination 1000-1500' above TPA, pull out the throttle and make a right hand descending 270 and enter the pattern, it is a change in perspective. I was based my first 7 years at a 3000' field exactly 4nm from a Class D, and whenever they stopped my descent at 4500 until I passed their runway, I always had to deviate to the right, make two 2 minute circles at 500 fpm, and slowdown while headed back to my little field.

There's no need to slow down during descent. Enjoy the speed payback! 

I began with an initial target of reaching TPA about 5 nm before the airport, so that i could slow down. With lots of practice, my target has moved closer. Now I just look at the ETE on the GPS, allow 2 minutes for every 1000' I must descend, and add another 2-3 minutes; when ETE reaches that number, push to establish descent.

Go have fun! I can't, my plane is in annual amd the weather, of course, is gorgeous.

Where are you, and which great Mooney model do you have?

P.S.--don't forget, the speed control knob / lever is beside your right knee. Moving it forward increases your speed, while moving it backwards reduces your speed. Just like a car, though, the effect vary depending if you are pointed uphill or downhill. 

Edited March 27, 2022 by Hank

[201er]

Mooneys can slow down or descend. Just not at the same time.

Edited March 27, 2022 by 201er

[Marc_B]

5 hours ago, carusoam said:

In an E-descent I may use 6kfpm…

Well, heck if an M20E descends at 6kfpm, I should start trying that in my K!   Ha ha ha. 

[Greg Ellis]

1 hour ago, Hank said:

Yes, airspeed builds rapidly, up to 165-170 mph, still in the green for my C model. This makes up for the slow climb to altitude

It’s interesting what a difference a few years makes.  In my 63 C model, the yellow arc starts at 150 mph.

[Hank]

1 hour ago, Greg Ellis said:

It’s interesting what a difference a few years makes.  In my 63 C model, the yellow arc starts at 150 mph.

There were several manufacturing changes fleetwide in 1969.

• I have a full-length rudder vs stopping at the horizontal stab
• My flaps are not mounted to the sub-spar
• Factory six pack panel
• Factory electric flaps and gear
• Four-piece cowl with dzus fasteners, for easy removal of either side panel without removing the top
• Probably more I can't think of

So the white Arc goes to 125 mph; green to 175; redline at 200 mph.

Thus is all part of why I asked the OP which model and year he has, because it can make a difference. Older Cs drop gear first to help slow to flap speed, while I drop flaps once I'm under 125 and gear below 120. So procedures and speeds vary accordingly. 

[Ragsf15e]

In smooth air, enjoy descent in the yellow arc.  Leave cruise power, trim forward, go fast.  500fpm works.  You’ll eventually have to start walking back the throttle as you get close to pattern altitude.  Plan to be at pattern altitude 3-5 miles early so you can slow down for gear/flaps.

[Hank]

1 hour ago, Marc_B said:

Well, heck if an M20E descends at 6kfpm, I should start trying that in my K!   Ha ha ha. 

Anthony moved from a C to an R, and apparently the long body falls out of the air faster in an Emergency Descent than my C does. Then again, my VSI doesn't reach 6000 fpm . . . . 

[carusoam]

Speed brakes deployed

Gear down

Throttle out

Prop in

Vlo

 

Lotso drag

at high speed

converting altitude to heat….

You will be on the ground in minutes….

 

Oddly, the airframe doesn’t feel any warmer… 

This is a great practice for transition training, good to see while somebody is familiar in the right seat…

It does include using the prop to drive the engine…

 

Down Elevator!  (The Otis variety not the control kind…)

-a-

[PT20J]

19 minutes ago, Hank said:

Anthony moved from a C to an R, and apparently the long body falls out of the air faster in an Emergency Descent than my C does. Then again, my VSI doesn't reach 6000 fpm . . . . 

Descent rate is going to be a function of drag. Drag increases as airspeed squared, so the higher the gear down speed, the faster you can come down. Also, a bigger engine/prop will generate more drag. Speed brakes and a high bank angle also help.

[PT20J]

I used to be based at KSJC where it seemed that there was always a steady stream of jets stretching all the way to Los Angeles lined up for the 30L ILS. In order to fit into the flow, the common request was at least 120 kts to the outer marker. I could do 140 and still cross the threshold at 65 without chopping the power in my 1978 J with no speed brakes. The trick was reducing power, dropping gear and flaps on schedule allowing enough time for steady deceleration. I worked out the procedure by letting the autopilot fly the ILS while I experimented with managing power and configuration. I had it figured out after a couple of tries.

Skip

[hubcap]

I don't try to slow down during descent. I simply pitch forward for 500 FPM down and enjoy the increase in speed. 

When I NEED to slow down I can throw the gear out or the speed brakes or both, in my M20K. Not sure what model the OP  has.

[Mooneymite]

I think the best way to descend the Mooney is just maintain a constant Mach until you need to slow for the landing.  

Just be careful of your neighbors....they hate the sonic booms.

Edited March 27, 2022 by Mooneymite

[Hank]

3 minutes ago, Mooneymite said:

I think the best way to descend the Mooney is just maintain a constant Mach until you need to slow for the landing.  

I'm quite happy with 0.22Mach!  

Although i need to dig out my aeronautical books and figure it for cruise speed at 8000 msl temp & pressure. I know the value will change, just not by how much . . . .

[Mooneymite]

5 minutes ago, Hank said:

I'm quite happy with 0.22Mach!  

Although i need to dig out my aeronautical books and figure it for cruise speed at 8000 msl temp & pressure. I know the value will change, just not by how much . . . .

Just take it from Schwarzenegger:  "I'll be Mach!"  

[A64Pilot]

All it really amounts to is to learn to be at pattern altitude further out, me I have a habit of descending 100 ft or so below, then climb the 100 and with power back that really slows me down, then get gear and flaps, probably foolish, but I like to be at the top of the white arc prior to dropping gear, I figure it’s easier on the actuator and no back spring

 For IFR approaches I plan on being gear and approach flaps set just before initial approach fix, it’s hard to hold a good glide slope while slowing, getting gear and flaps so I like to be stabilized prior to intercept, which means slowing down earlier than I used to in the 210. I don’t shoot many approaches anymore so I don’t do coupled approaches as I need the practice, but that a personal problem

[Hank]

7 minutes ago, A64Pilot said:

For IFR approaches I plan on being gear and approach flaps set just before initial approach fix, it’s hard to hold a good glide slope while slowing, getting gear and flaps so I like to be stabilized prior to intercept, which means slowing down earlier than I used to in the 210. I don’t shoot many approaches anymore so I don’t do coupled approaches as I need the practice, but that a personal problem

On approaches, I have Takeoff Flaps down and power set. Dropping gear and touching nothing starts my descent--with a glideslope, I drop gear 1-1/2 dots before intercept, and she rides the line perfectly after that.

[A64Pilot]

On 3/28/2022 at 9:10 PM, Hank said:

On approaches, I have Takeoff Flaps down and power set. Dropping gear and touching nothing starts my descent--with a glideslope, I drop gear 1-1/2 dots before intercept, and she rides the line perfectly after that.

I had a similar procedure for the 210, haven’t flown enough approaches in the Mooney yet to have one, but you do have to be in the white arc to get flaps, which if your not slowing way out can be tough, cause in a normal smooth air descent at 500 FPM at cruise power, I’m up near VNE in my J.

It’s not hard, it’s simply having to relearn the Cessna descent procedure most of us had prior to getting our Mooney’s, but until the Mooney becomes the new normal you do need to consciously begin slowing prior to when your used to. 

Edited March 30, 2022 by A64Pilot

[WaynePierce]

It probably makes a difference in which model you're flying... Try 15" of manifold, in my J that's pretty close to 500' pm and close to glide slope. Since I've started my IR training my CFII has me flying Cherokee speeds at 2300 RPM and 18" manifold pressure, it is easy to decend this way as well.

 

[PT20J]

In my J, 15” MAP level gets me into the white arc. I put 15deg flaps in one dot high on the GS which gives me 90 KIAS level and then I put the gear down at GS intercept and it will slide down the GS at 90.

I used to fly level at 20” and extend gear and flaps before GS intercept reducing power to 15” at intercept. Either way works, but my current method is a bit quicker when there are jets trailing me on the ILS.

Skip

[Utah20Gflyer]

On 3/27/2022 at 6:42 AM, 201er said:

Mooneys can slow down or descend. Just not at the same time.

It may be model dependent but I can slow down and descend at the same time in my G model but it requires pulling the throttle back to idle which I generally won't do because I have an aversion to listening to the gear horn for long periods of time.   There is also the potential for shock cooling although Im not really much of a believer in that.   I have had to do it occasionally but really try not to but sometimes terrain or airspace requires it.  

Usually I do what most here advise which is full power decent, normally at 2400 rpms, this makes sure the engine won't overspeed.  I usually plan for a long decent often 60 miles out if possible at 100 to 300 fpm. I try to be at pattern altitude maybe 3 to 5 miles out from the pattern so I have time to slow down.   Slow down technique is pull power to 16 inches, hold altitude and slowly trim the nose up.  Once I hit 105 mph prop goes full forward, check mixture and I'm ready to enter the pattern.  

Just a private pilot, so not expert advice.  

[Andy95W]

I plan my descent for 5nm per 1000’ and retard the throttle during the descent to maintain my cruise power (usually about 21-23”mp. Works very well. I can keep the engine pretty warm, not get too far into the yellow arc, and it keeps me from getting behind the airplane. 

[A64Pilot]

RE descending at very low power.

It’s not usually shock cooling you need to be concerned with unless your a turbo motor running high power/ high cyl head temps.

For us NA guys who are probably low head temp to begin with its usually not an issue, but what is, is the prop driving the engine, you want to avoid that possibility as it can “detune” the crankshaft counter weights

http://mechanicsupport.blogspot.com/2012/04/lycoming-or-continental-counterweight.html

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-103.pdf read paragraph 4(d) I believe.

This is for geared motors, but we are learning that direct drive motors can also be affected, geared moreso as the turn higher RPM

https://www.lycoming.com/sites/default/files/SB245D Detuning Dynamic Counterweight System.pdf

Its coming to light that a number of crankshaft failures are not poor manufactured or internal defects, but from the way the engine has been operated in the past.

So, if you keep power changes slow and gradual, you don’t have a concern, but also don’t reduce power a whole lot in a high speed descent so that the prop may drive the engine, you can use engine compression to slow a car as their counterweights don’t move, but you shouldn’t an airplane

Edited April 1, 2022 by A64Pilot

[MikeOH]

Does the IO360A1A even have a counterweighted crankshaft?  I didn't think it did.