M20 Hydraulic Pump Flap Diagram

[Shadrach]

2 minutes ago, Nukemzzz said:

By uniquely qualified I mean...

I’ve been a mechanical engineer for diesel fuel injection systems for 18yrs. 6 of those years leading the development and launch of these systems into Europe. 2yrs Prior to the 18 I was a service engineer explaining to technicians around the world how to troubleshoot Diesel engines (creating diagrams and steps like attached...but more professionally done...not in PowerPoint). The 9 years before that I was a certified auto/diesel technician. My current job is an engineering reliability leader and manager for the same systems. The majority of this current job consists of engineers presentIng to me their troubleshooting of design failures trying to convince me that they know what went wrong and how to fix it (answer is often no...lol). 

So then, might you recommend a good tuner for my BMW535D (N57)?

Edited April 14, 2020 by Shadrach

[Nukemzzz]

Just now, Shadrach said:

So then might you recommend a good tuner for my BMW535D (N57)?

Sorry, I know.very little about BMW Diesel engines. They probably use Bosch fuel systems with rotary pumps and piezo injectors and that’s about It. Lol

[Shadrach]

On 4/12/2020 at 11:02 PM, Nukemzzz said:

My M20e is grounded again while I sort out why the flaps won't stay down.  Three weeks ago the retract cable broke, I fixed that.  The flaps leaked up a little then but it seemed to be ok.  8hrs of flying later it retracts before you can complete touchdown on final which is dangerous...I had to take this bird apart yet again.   

Initial thoughts: 

Tighten the retract circuit all the way down.  If the flaps hold, you will know the problem is confined to the valve In that circuit. If they don’t hold then your problem is likely in the actuator circuit.

The eccentric that unseats the retract valve seat has a very abrupt step. There is not a lot of transition and therefor minimal possibility that the eccentric is partially holding the valve open. To set the cable after it has been disconnected, pump the flaps down and move the cable to the retract position. Move the arm on the eccentric until the flaps retract. Hold the arm in that position and tighten the cable.

If you are ever flying a plane again in which flaps will not stay down, do not use them. No flap landings and takeoffs won’t give you any trouble. Flying an airfoil that is subject to uncommanded changes in wing cord, center of pressure, lift generation and angle of incidence might...

Edited April 14, 2020 by Shadrach

[Shadrach]

11 hours ago, Nukemzzz said:

Sorry, I know.very little about BMW Diesel engines. They probably use Bosch fuel systems with rotary pumps and piezo injectors and that’s about It. Lol

I assure they use quite a bit more than that!...

[Nukemzzz]

10 hours ago, Shadrach said:

Initial thoughts: 

Tighten the retract circuit all the way down.  If the flaps hold, you will know the problem is confined to the valve In that circuit. If they don’t hold then your problem is likely in the actuator circuit.

The eccentric that unseats the retract valve seat has a very abrupt step. There is not a lot of transition and therefor minimal possibility that the eccentric is partially holding the valve open. To set the cable after it has been disconnected, pump the flaps down and move the cable to the retract position. Move the arm on the eccentric until the flaps retract. Hold the arm in that position and tighten the cable.

If you are ever flying a plane again in which flaps will not stay down, do not use them. No flap landings and takeoffs won’t give you any trouble. Flying an airfoil that is subject to uncommanded changes in wing cord, center of pressure, lift generation and angle of incidence might...

Yes, once I noticed the flaps raising by themselves we stopped using them all together. 

What you are describing is basically what I’ve done so far. I could feel the cam position in the lever and moved it to definitely closed. Flaps still leaked up. Tried running the adjuster all the way down. Not only did they still leak up, but the flap retract speed wasn’t changed..,they still popped up. So I removed the adjust screw to inspect the spring and ball and all I know is they were there. And this is why this is still a mystery. Something isn’t adding up. I haven’t came up for a theory yet that aligns with what Im seeing. Pump is out now though so further troubleshooting is impaired. I’m going to rebuild it and try again. 

The retract speed variable orifice seems to be an annulus orifice design with the restriction being the face of the adjuster.   I think I might find the ball seat damaged from the adjuster being tightened down with the ball out of place allowing a flow path even when the adjuster is full down. Not sure yet. 

Edited April 14, 2020 by Nukemzzz

[Shadrach]

1 minute ago, Nukemzzz said:

Yes, once I noticed the flaps raising by themselves we stopped using them all together. 

What you are describing is basically what I’ve done so far. I could feel the cam position in the lever and moved it to definitely closed. Flaps still leaked up. Tried running the adjuster all the way down. Not only did they still leak up, but the flap retract speed wasn’t changed..,they still popped up. So I removed the adjust screw to inspect the spring and ball and all I know is they were there. And this is why this is still a mystery. Something isn’t adding up. I haven’t came up for a theory yet that aligns with what Im seeing. Pump is out now though so further troubleshooting is impaired. I’m going to rebuild it and try again. 

If you've tightened the restrictor (retraction adjustment screw) all the way down, and the flaps are still retract at the same speed this suggests one that the o-ring (#27) on the restrictor is no longer sealing or that is fluid back flowing passed both actuator ball valves (small red arrows indicate proper flow direction).  A bottomed out retract adjustment screw close the retraction circuit completely regardless of the position of the ball on the seat unless the o-ring is toast. When did you first notice a flap problem and what corrective measures have been taken thus far?

 

 

[Nukemzzz]

O-Ring #27 is below the lock nut and seals that joint (not a good design that). 

Now that it’s apart I’m seeing #23 is missing. Not sure the purpose of #23 looking at the picture but it might be a spacer that restricts the flow of the retraction circuit. 

I-Ring #27 in the pic below. 

 

seat shown...I see a ball dent. Number #23 is missing. 

[Shadrach]

32 minutes ago, Nukemzzz said:

O-Ring #27 is below the lock nut and seals that joint (not a good design that). 

Now that it’s apart I’m seeing #23 is missing. Not sure the purpose of #23 looking at the picture but it might be a spacer that restricts the flow of the retraction circuit. 

I-Ring #27 in the pic below. 

 

seat shown...I see a ball dent. Number #23 is missing. 

Mine did not have 23 either. Steel ball on brass seat no spacer.

[Nukemzzz]

Without this part your system retracted slow?  It's not shown in my maintenance manual.  I wonder if some models have it and other do not.

I've not seen any other pictures of the inside of this part of the pump.  I'm wondering what #23 looks like.  I'm guessing its just a flat shim but I'm not sure.

Edited April 14, 2020 by Nukemzzz

[Shadrach]

28 minutes ago, Nukemzzz said:

Without this part your system retracted slow?  It's not shown in my maintenance manual.  I wonder if some models have it and other do not.

I've not seen any other pictures of the inside of this part of the pump.  I'm wondering what #23 looks like.  I'm guessing its just a flat shim but I'm not sure.

~11secs on the ground = ~4 in the air...I took this very short video about a year ago so folks could see how the system should work.

 

 

[Shadrach]

1 hour ago, Nukemzzz said:

O-Ring #27 is below the lock nut and seals that joint (not a good design that). 

Now that it’s apart I’m seeing #23 is missing. Not sure the purpose of #23 looking at the picture but it might be a spacer that restricts the flow of the retraction circuit. 

I-Ring #27 in the pic below. 

 

seat shown...I see a ball dent. Number #23 is missing. 

I must be loosing it...clearly the #27 oring is above the return orifice.  Perhaps 23 serves as a spacer.  I have an extra pump in my hangar.  I will be there on Thursday and give it a look. 

[Nukemzzz]

2 hours ago, Shadrach said:

I must be loosing it...clearly the #27 oring is above the return orifice.  Perhaps 23 serves as a spacer.  I have an extra pump in my hangar.  I will be there on Thursday and give it a look. 

That would be cool if you could verify and snap a picture of this part next to the adjuster screw. 

[Tcraft938]

Shadrach, if everything is done properly how many pumps should it take to fully deploy the flaps?  Mine takes 7 on the ground, no issues with it creeping up uncommanded. There are a few droplets of oil on the pump. It’s in annual now, so I can get at it and have the Lasar kit already. Thanks. 

[Shadrach]

15 hours ago, Nukemzzz said:

That would be cool if you could verify and snap a picture of this part next to the adjuster screw. 

Precisely 4 pumps...hydro-lock should be evident if a 5th pump is attempted.  See the video I posted a few posts ago.  The reason for making it was that so many folks were living with "soft" flap systems that required any number of pumps > 4 to  deploy full flaps.  

 

[Shadrach]

Also, this thread has inspired me to again review the factory literature.  It is horrible. No wonder there is confusion.  First, MM does not show the "washer"

that is depicted as #23 in the IPC (which neither of our planes have). And second, the MM shows the valves and flow oriented in reverse of the IPC.  See below. Say what you want about the physical system. Mooney's ability to assemble airplanes was far and away better than their ability to assemble technical data...

Edited April 15, 2020 by Shadrach

[Andy95W]

4 hours ago, Shadrach said:

Precisely 4 pumps...hydro-lock should be evident if a 5th pump is attempted.  See the video I posted a few posts ago.  The reason for making it was that so many folks were living with "soft" flap systems that required any number of pumps > 4 to  deploy full flaps.  

 

That's strange- I've had 2 different Mooneys with hydraulic flaps, they both required 4 and 1/2 pumps- which matches the Owner's Manual.

[Shadrach]

29 minutes ago, Andy95W said:

That's strange- I've had 2 different Mooneys with hydraulic flaps, they both required 4 and 1/2 pumps- which matches the Owner's Manual.

Perhaps the early birds had different actuators.  My POH makes no mention of the number of pumps required nor does the MM bleeding procedure (which is sub-optimal).  Most of the machines I've been associated with have been a 66 or later. All of them required precisely 4 pumps to lockout per the video I've linked.  I did talk @Sven  through bleeding his D model and I think his was also a 4 pump bird even though it was an early model (63?).  I think he sold it and moved on, so I doubt he'll chime in.  The OP is flying a 66E model and I am 99.9999% sure he will find that his is the same as my 67 (4 pumps). See the video I linked above (yes that's me). I always assumed the "four and one-half" in the early POHs to be a typo (would not be the first).  Oddly matched set of components (pump and actuator) if fractions of a pump are SOP.  When you land full flaps, is the pump handle sticking up half way up?  It would be nice to know what is different about your flap system over mine. It would benefit the community to know why essentially identical systems operate differently.  In my case the actuator has precisely 4 times the volume of the pump.  Dev @DXB has a C with manual flaps and IIRC his is 4 pumps from no flaps to hydrolock just like my F.

Edited April 15, 2020 by Shadrach

[Andy95W]

That POH was for 1962-1965.  My first Mooney was a 1967 M20C, and it was also 4 and 1/2 (actually mine's probably closer to 4 1/4 pumps).  The handle does stick out some at full flaps on landing, and when it hydrolocks it feels like it hits a physical stop.  Maybe the extra half accounts for a little air in the system, and you were better at bleeding it out.

I bet they changed the POH because too many people were complaining that they weren't getting full flap extension when they actually were.  It was cheaper to change the POH than determine why individual airplanes differed!

[Nukemzzz]

My 66’ E was 5.5 pumps before taking the pump off. 

I’m rebuilding the pump and putting back together Friday. My IA wants to bench test it before install, does anyone know what pressure the  retraction circuit ball should hold?  My 1982 MM has no detail on pump performance specs. 

[DXB]

3 hours ago, Shadrach said:

Perhaps the early birds had different actuators.  My POH makes no mention of the number of pumps required nor does the MM bleeding procedure (which is sub-optimal).  Most of the machines I've been associated with have been a 66 or later. All of them required precisely 4 pumps to lockout per the video I've linked.  I did talk @Sven  through bleeding his D model and I think his was also a 4 pump bird even though it was an early model (63?).  I think he sold it and moved on, so I doubt he'll chime in.  The OP is flying a 66E model and I am 99.9999% sure he will find that his is the same as my 67 (4 pumps). See the video I linked above (yes that's me). I always assumed the "four and one-half" in the early POHs to be a typo (would not be the first).  Oddly matched set of components (pump and actuator) if fractions of a pump are SOP.  When you land full flaps, is the pump handle sticking up half way up?  It would be nice to know what is different about your flap system over mine. It would benefit the community to know why essentially identical systems operate differently.  In my case the actuator has precisely 4 times the volume of the pump.  Dev @DXB has a C with manual flaps and IIRC his is 4 pumps from no flaps to hydrolock just like my F.

Yup - mine was about 4.5 pumps when I first got the plane and then exactly 4 pumps once I got all the air out of the system.   Pumping the handle a million times without having the switch to keep flaps down engaged works very well to get the air out.  

[Shadrach]

48 minutes ago, Nukemzzz said:

My 66’ E was 5.5 pumps before taking the pump off. 

I’m rebuilding the pump and putting back together Friday. My IA wants to bench test it before install, does anyone know what pressure the  retraction circuit ball should hold?  My 1982 MM has no detail on pump performance specs. 

So someone was definitely in there before you purchased it. 

[Shadrach]

1 hour ago, Andy95W said:

That POH was for 1962-1965.  My first Mooney was a 1967 M20C, and it was also 4 and 1/2 (actually mine's probably closer to 4 1/4 pumps).  The handle does stick out some at full flaps on landing, and when it hydrolocks it feels like it hits a physical stop.  Maybe the extra half accounts for a little air in the system, and you were better at bleeding it out.

I bet they changed the POH because too many people were complaining that they weren't getting full flap extension when they actually were.  It was cheaper to change the POH than determine why individual airplanes differed!

You may be right about the POH change. It is a challenge to get all the air out of the system. Especially if you follow the bleeding procedure in my maintenance manual which IIRC instructs the user to bleed from the top. With regard to your flaps, the question is not whether or not you reach a Hydro lock position at full flaps but whether or not you get movement immediately on the first pump.  My system has no air in it and every millimeter of handle movement translates to movement in the flaps. There is no energy loss between the two. This can be seen in the video by watching the indicator during the second deployment.

[Andy95W]

I get movement on the first pump, but more on pumps 2, 3 and 4.

[Shadrach]

9 minutes ago, Andy95W said:

I get movement on the first pump, but more on pumps 2, 3 and 4.

One pump takes mine to the take off position.

[Skates97]

Mine (65 D) is two for take off position and 4 1/2 for full flaps which is also what the POH says.