My Mooney is too fast.

[A64Pilot]

28 minutes ago, ArtVandelay said:

I think the gear limit is about stress on the gear doors and associated hardware. I think our gear is robust enough to handle any speed below yellow.
But I agree, I try not to test the limits.

Door limits certainly, actuator may be next? The gear themselves are certainly never really stressed at any retraction or extension speed. I’ve seen cracked doors and you have to wonder what stress causes a door to crack, cracks are usually not one time overloads but repetitive stress, a vibration or flutter maybe? But if they are operated so that they don’t flutter or vibrate, then they ought to last well, pretty much forever.

[Philip France 13]

Hello

On M20J MSE : my way of managing descent is using 6NM to lose 1000ft, 5000ft for example must start t odescent 30NM befote. If too short i slow down to 120kt and retract the gears, the. Go to 100kt or even 90kt full flaps and 500 to 700ft per minute you will use your altitude and still be able to fly the plane safely. IFR approach into LFLP Annecy in the alps is quite steep and it works well.

philip

[jaylw314]

Pull the prop to keep heat in the motor during descents

Push the prop to slow down during descents.

I should point out even the POH says that max descent rate is similar with gear up vs gear down, but it strongly implies gear down is the better choice

If I'm faster than Vle, I'll regularly level off or even climb a bit to slow down to extend the gear while flying IFR.  ATC is not going to notice altitude changes, especially climb rate changes, very quickly.

If you're descending at max descent rate, at least you don't have to worry about the mandatory report of descending less than 500 feet per minute.  Sometimes I think I'm the only one who still does that!

Oh good grief, I'm starting to write like @carusoam! 

[ilovecornfields]

5 hours ago, jaylw314 said:

If you're descending at max descent rate, at least you don't have to worry about the mandatory report of descending less than 500 feet per minute.  Sometimes I think I'm the only one who still does that!

Well, you’re certainly the only one I’ve heard in 30 years of flying reporting “unable to climb 500 fpm.” 
 

I had completely forgotten about the requirement to report that until I got home and looked it up. I’m willing to bet you got 100% on your IFR written exam.

[Seth]

I love posts with titles like this.

-Seth

[PilotX]

12 hours ago, Seth said:

I love posts with titles like this.

-Seth

Agree. The first world problems we experience. Dropping into the pattern at 165 knot surrounded by 172s and 152s.

[Hank]

50 minutes ago, PilotX said:

Agree. The first world problems we experience. Dropping into the pattern at 165 knot surrounded by 172s and 152s.

Just need to start descent a couple of miles earlier, then you can level off and slow down . . . .

[philiplane]

So far no one has mentioned slowing down first by pulling up. Reduce power substantially, and add back pressure to hold altitude and then climb slowly, less than 100 feet so you don't bust your altitude. Fighting gravity is the best speed brake. You will shed 20 knots quickly. Then gear out, put back normal descent power, and descend.

Edited July 1, 2021 by philiplane

[DXB]

A Mooney that's too fast? Seems kinda like being too rich or too good looking 

[GeeBee]

ATC: ABC 1234 cross Intersection at maintain 1-5 thousand

ABC 1234: Unable, we're too close and too high

ATC: You got speed brakes don't you?

ABC 1234: Yep, but those are for our mistakes, not yours.

Another one, true story

ATC: Delta 1234 cross intersection or below 1-1 thousand

Delta 1234: This here airplane is made by the Douglas Airplane Company, not the Otis Elevator Company.

 

 

 

[Hank]

I'll have to remember that Delta line!

[jaylw314]

22 hours ago, ilovecornfields said:

Well, you’re certainly the only one I’ve heard in 30 years of flying reporting “unable to climb 500 fpm.” 
 

I had completely forgotten about the requirement to report that until I got home and looked it up. I’m willing to bet you got 100% on your IFR written exam.

Yeah, that cracked me up the we passed each other that day! 

[Steve Yucht]

FWIW I start calling ATC to request lower when I calculate (really foreflight calculates) a 500ft/min descent.  If they say anything but a lower altitude they will always tell me lower in "x" minutes.  I then start my mental calculus.  If it looks like a slam dunk just start to slow down.  If I dont have my wife in the plane with me I'll do 1500 ft/min but with her I keep things reasonable.  In the soup I stick with 500 ft/min no matter what. Really no big deal as long as you can be reasonably close to crossing restrictions and not high by the FAF.  Worst case they vector you around.  Remember if you say unable to ATC when they left you high it's a reflection on them and they will likely fix your problem so their supervisor doesn't keep hearing you say unable.  

[ArtVandelay]

If not in IMC, just cancel and go VFR. I’ve been still at 5000’ and less than 15 miles away and have my request to descend refused.
They usually aren’t happy, probably messing up their flow of traffic.

[Hank]

5 hours ago, ArtVandelay said:

If not in IMC, just cancel and go VFR. I’ve been still at 5000’ and less than 15 miles away and have my request to descend refused.
They usually aren’t happy, probably messing up their flow of traffic.

I was inbound to Raleigh to carry hurricane relief supplies to the coast, very much VFR. Tower kept me at 7500 (I stopped asking to descend after the second refusal) and vectored me > 10nm north before turning me inbound and clearing me to land #8 on 23L. 

[GeeBee]

On 6/30/2021 at 8:27 PM, ilovecornfields said:

Well, you’re certainly the only one I’ve heard in 30 years of flying reporting “unable to climb 500 fpm.” 
 

I had completely forgotten about the requirement to report that until I got home and looked it up. I’m willing to bet you got 100% on your IFR written exam.

Some years ago when I was a First Officer, the Captain was slow climb out of DFW. I said, "Do you want me to tell them we are slow climb?" He said, "Nah". Well yep, about a month later we got a letter.  Controller had loss of separation, and he blamed us. No action was taken but we were admonished. I never did less than 500 fpm ever again without notifying ATC, even on P/D clearances. 

[jlunseth]

On 6/27/2021 at 5:57 PM, Glen Davis said:

Today I flew from Central Maine to an airport in the New York City area. I was IFR on top of a solid cloud deck at 6000 feet. I asked for lower as I was getting close to my destinations airport, in the class bravo, and I was planning my approach but ATC could not give me lower when asked. Finally, about 15 miles prior to the initial approach fix they gave me 3000. I lowered the nose to give a 500 ft./min. descent and as expected the indicated airspeed increased to approximately 165 knots.  I was in the soup and getting bounced around and wanted to slow down closer to maneuvering speed. I reduced the manifold pressure 13 inches and brought the prop back to 2200. Still I was too fast for the rough ride I was experiencing. Other than leveling off and letting the indicated airspeed bleed off to gear extension speed, then lower the gear, what else can one do to slow down  when in turbulence and on a dissent. I don’t have those funny things that pop out of the wings to help.  Glen

Is this a question or a brag.

Ask around, there are many guys on here who have been asked to slow down for the Citation (or Lear, or Cardinal, or Cirrus) on final. I think the factory paint included some asbestos to deal with the heat of reentry. I hear you can get a ceramic coating now, that should help.

[RJBrown]

My too fast story.

Rocket without speed brakes. IFR to Denver’s Centennial from the south west. Center keeps you high over LARKS and configures your decent as if you are headed to FALCON and DIA. Once center hands you off to approach you are almost to APA and still above 10,000‘ Approach immediately had me on the ILS above 200 knots with all power pulled out. There was a solid cloud deck between 1-2000’ agl. I called the miss at CASSI, above the clouds, went around and had a stabilized approach. That slam dunk was an every time event entering the Denver area IFR from LARKS. Even anticipating the slam dunk and having power back to Rockets Minimum decent power. The Mooney was too fast without speed brakes to comply safely. I couldn’t bear to drop gear and flaps 30 miles out and come in like a Cessna. If the airport wasn’t IFR it was easier to cancel back at LARKS and configure your own decent for a VFR landing. Leave center early and not waste all that climb energy by keeping speed up in a longer decent.

 

[MBDiagMan]

Speed Brakes!  One of the very best mods for a Mooney..

[jaylw314]

3 hours ago, RJBrown said:

My too fast story.

Rocket without speed brakes. IFR to Denver’s Centennial from the south west. Center keeps you high over LARKS and configures your decent as if you are headed to FALCON and DIA. Once center hands you off to approach you are almost to APA and still above 10,000‘ Approach immediately had me on the ILS above 200 knots with all power pulled out. There was a solid cloud deck between 1-2000’ agl. I called the miss at CASSI, above the clouds, went around and had a stabilized approach. That slam dunk was an every time event entering the Denver area IFR from LARKS. Even anticipating the slam dunk and having power back to Rockets Minimum decent power. The Mooney was too fast without speed brakes to comply safely. I couldn’t bear to drop gear and flaps 30 miles out and come in like a Cessna. If the airport wasn’t IFR it was easier to cancel back at LARKS and configure your own decent for a VFR landing. Leave center early and not waste all that climb energy by keeping speed up in a longer decent.

 

That sort of thing is worth dropping the gear and coming in like Cessna.  Flying into KSMO's RNAV 21 from the north, the controller apologized and said the MVA was 7000 until the initial waypoint DARTS.  You're vectored 2 miles outside the FAF at 3000', which means you have to lose 4000' in 2.6 miles (less if they do you the "favor" of cutting the corner).  It's JUST barely doable if you put the gear out and drop like a rock.

Edited July 3, 2021 by jaylw314

[Pete M]

In my e i'd pull prop back to 1950 and throttle to just above gear horn. Worked very well. High rpm gets the prop driving the engine. Not an a&p but as i understand it thats not the engines happy place...

Teach out of 39n...never met caruso...:)

Pete

[Yetti]

Pull the power back.  the further you pull it back the slower you will go.

The plane flies really different at 21 21.  Go out and practice it so you get a feel for it.

Other ways to manage energy

You have speed brakes they just come out of the bottom of the wing.

Flaps

Slip for really slow

You can also do S turns to eat up altitude.

I actually did the getting slammed from 5000 feet with gear it worked pretty well.

Need to upload the video.

 

[carusoam]

On 7/3/2021 at 9:31 AM, Pete M said:

In my e i'd pull prop back to 1950 and throttle to just above gear horn. Worked very well. High rpm gets the prop driving the engine. Not an a&p but as i understand it thats not the engines happy place...

Teach out of 39n...never met caruso...:)

Pete

Let me know when you are available….  We should talk…

Best regards,

-a-

[A64Pilot]

On 7/3/2021 at 9:31 AM, Pete M said:

In my e i'd pull prop back to 1950 and throttle to just above gear horn. Worked very well. High rpm gets the prop driving the engine. Not an a&p but as i understand it thats not the engines happy place...

 

It’s a very bad thing to do to an engine as it may I believe the term used is detune the crankshaft balance weights. 

I know that’s a possibility in a fixed pitch aircraft especially in a dive, but I thought that a constant speed props governor would help prevent that as if RPM begins to exceed the set point, the governor will add pitch to prevent an over speed. But to autorotate the prop will take pretty much a dive I thought, something most wouldn’t do.

I’ve pulled the engine back on turbines and dove steeply and initially the big prop keeps the speed low, it acts like a brake, then suddenly the governor adds pitch because the prop is auto rotating and you accelerate, but it takes a pretty steep dive to do that though.

Tjese are NOT our engines, but it explains what happens.

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

Then read 4(d) here

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-103.pdf

I think that we are fine to leave the prop at high RPM, just don’t pull the throttle off fast and or dive the airplane, rapid changes in RPM is bad.

 

Edited July 10, 2021 by A64Pilot

[PT20J]

Every power stroke twists the crankshaft. Lower powered engines can make the crankshaft heavier to withstand this, but higher powered engines usually use dynamic counterweights. The counterweights are supported by two pins through bushed holes with a mathematically-determined loose fit and act as pendulums whose motion lags behind the twist of the crankshaft during a power pulse thereby absorbing some energy that would otherwise be absorbed by the crankshaft. After the power pulse, the pendulum motion again lags behind the untwisting of the crankshaft returning energy to the crankshaft. Thus, they absorb and return energy without extracting power.

The counterweights are "tuned" to a specific harmonic, or "order", of the crankshaft rpm. Because of their mounting (round pins in larger round holes) they can move in and out relative to the centerline of the crankshaft and this allows them to adjust to a range of engine speeds.

During normal engine operation, the pistons apply a reciprocating "pull" on the crankshaft due to their mass and velocity as the piston moves from BDC to TDC. This load is normally offset by the opposite "push" loads on the crankshaft by combustion gasses during the power strokes. When running at high rpm and low manifold pressure, the balance of theses forces is disturbed and this can cause torsional vibrations that are outside the design range of the counterweights. The counterweight bushings then bang rapidly against the pins damaging them. This "detunes" them -- essentially making them work at a different frequency than desired and leaving the desired frequency unchecked. This can lead to vibration induced engine issues. These engines are pretty robust; it takes a lot of abuse to damage them. But repeated abuse adds up.

John Schwaner explained this a lot better in his Sky Ranch Engineering Manual.

Lycoming engine numbering indicates the counterweight configuration.

On the IO-360-A3B6D, the 6 indicates one 6th and one 8th order counterweight.

SSP-110-2 Certified Engines.pdf

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