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HELP! Apparently, my Mooney is SLOW


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These speed threads, as of late, have got me in a funk.  Previously, I thought I was moving right along...I guess I'm flying a slug.

My 1970 M20F has the following mods:  Lower cowl closure; 201 windshield; gap seals on ailerons, flaps, elevator; one piece belly, dorsal fin mod; PowerFlow exhaust.

At 10,000 DA, WOT, 2500 rpm, 10.3 gph, 2250 lbs. I'm only seeing 146 kts :(  Cowl flaps open or closed didn't seem to make even 1 knot difference???

So, what say the cognoscenti on what order I should attack the following (most bang for the effort):

Flap rigging

Aileron rigging

Nose gear doors

Main gear doors

Fixed step (I'm willing to ditch the thing if there will be a marked improvement)

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2 minutes ago, MikeOH said:

These speed threads, as of late, have got me in a funk.  Previously, I thought I was moving right along...I guess I'm flying a slug.

My 1970 M20F has the following mods:  Lower cowl closure; 201 windshield; gap seals on ailerons, flaps, elevator; one piece belly, dorsal fin mod; PowerFlow exhaust.

At 10,000 DA, WOT, 2500 rpm, 10.3 gph, 2250 lbs. I'm only seeing 146 kts :(  Cowl flaps open or closed didn't seem to make even 1 knot difference???

So, what say the cognoscenti on what order I should attack the following (most bang for the effort):

Flap rigging

Aileron rigging

Nose gear doors

Main gear doors

Fixed step (I'm willing to ditch the thing if there will be a marked improvement)

You might be a little slow.  I have a 76F with only the lower cowl closure and get 142-143 TAS on 9gph.  Flight control rigging is probably a good place to start.

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^^^^This is a good spot to start. Make sure your rigging is right, then maybe make sure your tach is correct and your airspeed indicator is good. Are you calculating the 146 TAS or getting it off of something like an Aspen or Garmin GPS?

And the gear doors are easy to check at annual when it is up on jacks.

Edited by Oldguy
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12 minutes ago, Oldguy said:

^^^^This is a good spot to start. Make sure your rigging is right, then maybe make sure your tach is correct and your airspeed indicator is good. Are you calculating the 146 TAS or getting it off of something like an Aspen or Garmin GPS?

And the gear doors are easy to check at annual when it is up on jacks.

Tach is Horizon digital, so I'm pretty sure that's okay:)

The 146 kts was a three-way "horseshoe'" GPS speed test, so airspeed indicator was not even a factor.

I've got a friend with jacks, so maybe I check that first at no cost; having the rigging checked sounds expensive...

Thanks!

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Rigging check isn’t very expensive... put the measuring tool on the wing and see what it says... it can be comfortable to know it is well rigged...

If it is out of rig... the fix takes a lot of time and flights to get right... that time gets expensive...

PP thoughts, not a mechanic...

Best regards,

-a-

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You’re within a knot of me.  I appreciate that you did the 3 way speed test instead of just saying you get 175mph TAS based on your Aspen/G5/430W or whatever.  

Try same power settings at 6500’ (will be more fuel flow).  Likely hit 150.

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1 hour ago, carusoam said:

Rigging check isn’t very expensive... put the measuring tool on the wing and see what it says... it can be comfortable to know it is well rigged...

If it is out of rig... the fix takes a lot of time and flights to get right... that time gets expensive...

PP thoughts, not a mechanic...

Best regards,

-a-

Ah, good point!  Do you happen to know where they are for rent?

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1 hour ago, Ragsf15e said:

You’re within a knot of me.  I appreciate that you did the 3 way speed test instead of just saying you get 175mph TAS based on your Aspen/G5/430W or whatever.  

Try same power settings at 6500’ (will be more fuel flow).  Likely hit 150.

What mods does your F have?

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On 6/21/2019 at 8:44 PM, MikeOH said:

These speed threads, as of late, have got me in a funk.  Previously, I thought I was moving right along...I guess I'm flying a slug.

My 1970 M20F has the following mods:  Lower cowl closure; 201 windshield; gap seals on ailerons, flaps, elevator; one piece belly, dorsal fin mod; PowerFlow exhaust.

At 10,000 DA, WOT, 2500 rpm, 10.3 gph, 2250 lbs. I'm only seeing 146 kts :(  Cowl flaps open or closed didn't seem to make even 1 knot difference???

So, what say the cognoscenti on what order I should attack the following (most bang for the effort):

Flap rigging

Aileron rigging

Nose gear doors

Main gear doors

Fixed step (I'm willing to ditch the thing if there will be a marked improvement)

At 10,000ft I’d say you're doing just fine. It’s an NA airplane. It’s going to be fastest at ~5000ft

Edited by Shadrach
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7 hours ago, MikeOH said:

Ah, good point!  Do you happen to know where they are for rent?

There is a thread around here regarding attempts at making or copying the tools...

There was a place called hangar toolbox that used to rent them... see if these guys still exist?

A couple of MSers have the tools... 

MSCs typically have the tools, and probably can do the job with an hour of time...?

Mooneys typically don’t go out of rig on their own... So owning one of these tools isn’t very helpful, long term...

PP thoughts only, not a mechanic...

Best regards,

-a-

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9 hours ago, carusoam said:

There is a thread around here regarding attempts at making or copying the tools...

There was a place called hangar toolbox that used to rent them... see if these guys still exist?

A couple of MSers have the tools... 

MSCs typically have the tools, and probably can do the job with an hour of time...?

Mooneys typically don’t go out of rig on their own... So owning one of these tools isn’t very helpful, long term...

PP thoughts only, not a mechanic...

Best regards,

-a-

Good points.

Looks like hangartoolbox.com is dead:(

It can't hurt to call the local MSC and ask.

Thanks

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On 6/21/2019 at 8:44 PM, MikeOH said:

At 10,000 DA, WOT, 2500 rpm, 10.3 gph, 2250 lbs. I'm only seeing 146 kts :(  Cowl flaps open or closed didn't seem to make even 1 knot difference???

If your POH performance is the same as mine, you’re only a few knots below book at that fuel flow.  You’re probably below 75%.  Try the same conditions but 2700 rpm.  More power strokes per minute (more fuel) should help.  Is your ram air working?  It should give you a knot or two.

 

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1 hour ago, Cyril Gibb said:

If your POH performance is the same as mine, you’re only a few knots below book at that fuel flow.  You’re probably below 75%.  Try the same conditions but 2700 rpm.  More power strokes per minute (more fuel) should help.  Is your ram air working?  It should give you a knot or two.

 

You are correct.  It's just 70% power.  Thing is, at that setting, and weight, book is 172 mph for stock; I was only seeing 168...and I've got all the mods!:(

Edited by MikeOH
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16 hours ago, Jerry 5TJ said:

Compared to some Mooneyspace claims each of my three Mooney airplanes was slow.  

Good thing I never had to buy one of your well sorted, well maintained, but slow planes. If you can’t keep up with MS you are well off the pace. 

(As I type this in rearranging my portfolio to make sure I’m ready to buy when you get bored with the p46t.)

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On 6/21/2019 at 7:44 PM, MikeOH said:

At 10,000 DA, WOT, 2500 rpm, 10.3 gph, 2250 lbs. I'm only seeing 146 kts :(  Cowl flaps open or closed didn't seem to make even 1 knot difference???
 

Way to humblebrag. I went to Flightaware and looked up at times when I was cruising between Utah (CDC) and Nevada (RNO), when the radar coverage made me stick to 11.500. I was making 130 knots against the wind, 135 with the wind. That's all she can give at these altitudes. Burns 9.8 gph at 2350 rpm. Going any richer for me does absolutely nothing, in fact slows it down a bit. The MP at 11.5 is about 19.5" with the intake door open. I can only make the plane go any faster at lower altitudes, where IO-360 makes the power. I'd love to be zipping at 146 kts up high :-)

Edited by zaitcev
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On 6/22/2019 at 9:40 PM, MikeOH said:

You are correct.  It's just 70% power.  Thing is, at that setting, and weight, book is 172 mph for stock; I was only seeing 168...and I've got all the mods!:(

The 70's were a bit slower than the earlier ones with the clean wing. I saw 146 TAS out of my 70 when I owned it. Ari cowl closure, 2 blade hartzell. When I hung a 3 blade Hartzell on it, best it would do is 140, and the vibration was much worse and couldn't be balanced out by Hartzell. Off came the 3 blade, new 2 blade ordered.

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Its all in your head..... and ego. That is a reasonable speed for an F. Let it go, enjoy your airplane, and be happy. IF you go throwing $$$ at this it will likely lead you to be more unhappy, because the return will be small.

5 knots either direction is meaningless. You will make or lose time with how efficient you are on the ground and technique.

Edited by Immelman
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On 6/21/2019 at 7:54 PM, Oldguy said:

^^^^This is a good spot to start. Make sure your rigging is right, then maybe make sure your tach is correct and your airspeed indicator is good. Are you calculating the 146 TAS or getting it off of something like an Aspen or Garmin GPS?

And the gear doors are easy to check at annual when it is up on jacks.

Yes, make sure that the edges of the doors don’t extend such that they won’t tuck in out of the airstream.  Paul Maxwell showed me how mine weren’t fitting well and cost several knots.  Also make sure the wing leading edge about 12” behind on both top and bottom are clean and even waxed.  A former Mooney test pilot told us at a seminar that this could cost a couple of knots.  It all adds up.

My F has ALL the J modifications and it’s not much faster than the OP’s.

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