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Engine Droop

mulro767

By mulro767
in Modern Mooney Discussion

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mulro767 Rising Star

mulro767

Posted
Posted

So I dropped off my J at Willmar yesterday for my first annual.  When asked by Brian if I had a squawk list, I said everything was good except for some vibration that recently started near the floor in front of co-pilot.  Of course as a pilot I had to throw my educated guess in there and said "loose cowl flap maybe?"  After looking at the airplane for 5 seconds he said "No, your engine is drooping about 1 inch."  I looked at the cowl profile and couldn't believe my eyes.  The spinner was sagging below the top of the cowling.  So far, impressed with a MSC.  How did I not notice that anyway?  


So some questions: Anyone have this issue?  He mentioned they could possibly shim it if the mounts were in good condition. Would it be best to just replace?  Is this a big cost fix?  I'm still plane broke and was hoping for a gentle first annual.  And finally, could I expect to see some performance increase?  From the front with the sag you can see the cowling opening where normally you wouldn't.  


Thanks in advance for the intel!  I am glad that I'm doing this at Willmar.  Thanks to those who steered me their way.

Cruiser Grand Master

Cruiser

Posted
Posted

Be prepared. Willmar is an excellent MSC and they know Mooneys inside and out. They will find stuff. I suggest you establish a protocol with Brian about repairs and costs to define what work will be done.

Steve Dawson Experienced

Steve Dawson

Posted
Posted

When I had my J in for the original inspection Clarence had noticed about the same amount of droop. He shimed the engine and I noticed approximately 4-5 knots increase.

Ned Gravel Grand Master

Ned Gravel

Posted
Posted

Quote: Fastbyk

When I had my J in for the original inspection Clarence had noticed about the same amount of droop. He shimed the engine and I noticed approximately 4-5 knots increase.

aerobat95 Mentor

aerobat95

Posted
Posted

Can you guys take a look at these pics and let me know what you think?  I cant tell if my engine is drooping or not.  I just know the clearance at the bottom of the spinner to the cowl is very tight.  Thanks.


 

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GeorgePerry Veteran

GeorgePerry

Posted
Posted

The clearence issue is more a function of how the cowl closure mod was fitted than engine "droop".  If the mounts are in good shape (and they are Laughing) then the motor's aligned properly.

  • Like 1
aerobat95 Mentor

aerobat95

Posted
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Cool...thanks for the info.  Hey George, I flew from San Antionio, TX to Enid, OK and was averaging 155KTAS.  The mods came out awesome.  2 hours 41 minutes from T/O to Landing.  Was so much better than the drive.  Anyway the plane is flying really good. 

GeorgePerry Veteran

GeorgePerry

Posted
Posted

Good to hear...Sometimes Mods don't net much speed increase, but in your case it sounds like it was money well spent.  That's about 8-10 kts faster than I ever expereinced when running ROP.

  • 3 years later...
Awqward Rising Star

Awqward

Posted
Posted

Discovered today I have a "droopy" engine too....only I found out the expensive way! The spinner backplate had obviously been rubbing on the lower cowl for some time and finally the backplate cracked...damaging the spinner in the process...

I noticed a burning smell on approach to my home airport which I thought was electrical and started shedding avionics one by one....when I put the gear down there was a sudden "puff" from the nose far too quick for my eyes/brain to register anything but disturbing nonetheless...when I landed I didn't have time to investigate but I went back today and removed the cowl to see the shocking images attached....there were bits of aluminum across the cylinders and resting at the front of the oil cooler as well as shredded fiberglass in the air filter and oil cooler....so now I am in the market for a new spinner and backplate and obviously some shimming of my engine mounts!

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Marauder Grand Master

Marauder

Posted
Posted

Discovered today I have a "droopy" engine too....only I found out the expensive way! The spinner backplate had obviously been rubbing on the lower cowl for some time and finally the backplate cracked...damaging the spinner in the process...

I noticed a burning smell on approach to my home airport which I thought was electrical and started shedding avionics one by one....when I put the gear down there was a sudden "puff" from the nose far too quick for my eyes/brain to register anything but disturbing nonetheless...when I landed I didn't have time to investigate but I went back today and removed the cowl to see the shocking images attached....there were bits of aluminum across the cylinders and resting at the front of the oil cooler as well as shredded fiberglass in the air filter and oil cooler....so now I am in the market for a new spinner and backplate and obviously some shimming of my engine mounts!

Wow! Never seen anything like that...

Awqward Rising Star

Awqward

Posted
Posted

23 hours since oil change....didn't notice anything, 66 hours since annual inspection...obviously nothing noted...new engine mounts (Lords) at engine OH 134 hours ago.,,

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Awqward Rising Star

Awqward

Posted
Posted

So do I go to Hartzell for the full spinner assy ($2500?) or try and scrounge around for a spinner and the fore and aft back plates?

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Guest

Guest

Posted
Posted

Can you guys take a look at these pics and let me know what you think?  I cant tell if my engine is drooping or not.  I just know the clearance at the bottom of the spinner to the cowl is very tight.  Thanks.

I would say its a bit low. Usually there is room for the tip of your index finger between the cowl and the spinner on the top side. The fit of the Lasar closure is based on the engine being at the correct height.

Mooney manuals tell you to reinstall the engine using the same shims in the same location when reinstalling the engine. Sadly many maintainers don't realize there are different shims install at the factory when the engine is first installed and many are lost during engine removal.

If the engine is sagging in the airframe, various parts contact things they are not meant to, ie prop spinners, mufflers etc. Aside from damage, the thrust line of the engine is now not as designed, if the engine is trimmed down several degrees, the tail must be trimmed up to correct, excess trim is drag and loss of speed. I have never seen a published engine angle realatively to the longitudinal axis of the fuselage.

On a J model engine droop can be further compounded by a loose engine cowl which rides up in flight. Lasar has a fix for the loose cowl.

Clarence

triple8s Mentor

triple8s

Posted
Posted

Seriously, you may save money scrounging but it might take some time and if you don't get to look the used spinner and bulkheads over closely to check the fit you may end up with more trouble and a big waste of time and money. I never realized how much could be wrong with the spinners and bulkheads till I assisted my mechanic with work on a 310 C. One of its spinners had been operated while loose and the holes for the screws were enlongated, and the bulkhead where it fits the end of the prop had been working, the fit between things was loose. I'd want to see what I was buying if I bought used stuff.

Awqward Rising Star

Awqward

Posted
Posted

So I called Hartzell and this one of the few models of prop that they didn't make the spinner for...it's a Mooney spinner from Mooney...

carusoam Grand Master

carusoam

Posted
Posted

Check all the weld points on the motor mount/cradle.

My 65C broke a couple lower welds. Casual visual inspection didn't reveal why my prop/engine was drooping.

I flew it to the local MSC to have them show where the welds used to be...

Noticeable drooping is worthy of stopping to find out why it is happening.

Thought I might be crazy fearing the engine was drooping. Found out I was crazy for accidentally flying without a proper engine mount.

Best regards,

-a-

  • Like 1
Awqward Rising Star

Awqward

Posted
Posted

Thanks Anthony....yes that is high on my list! I'm out of town this week and my A&P isn't back either until the 28th....but this weekend I will pull the cowls again and have really good look...the engine mounts were replaced at overhaul 134 hours ago and I'm hoping they've just been slowly bedding in...

I just spoke to Dan at Lasar and he recommends a different spinner assembly...from Hartzell....with a thicker backplate that doesn't bolt directly to the ring gear....just going to check with my IA before committing but it sounds good...

Marauder Grand Master

Marauder

Posted
Posted

Thanks Anthony....yes that is high on my list! I'm out of town this week and my A&P isn't back either until the 28th....but this weekend I will pull the cowls again and have really good look...the engine mounts were replaced at overhaul 134 hours ago and I'm hoping they've just been slowly bedding in...

I just spoke to Dan at Lasar and he recommends a different spinner assembly...from Hartzell....with a thicker backplate that doesn't bolt directly to the ring gear....just going to check with my IA before committing but it sounds good...

I didn't catch the "134 hours ago" part earlier in the thread. Unless there was a failure of the mount or it was installed incorrectly (if that is even possible), I agree with Anthony about looking for a break in your engine mount.

You should not have a engine droop issue after 134 hours on the mounts.

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