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Shock Mount Removal Effect on Gyros


cctsurf

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For those of you who have upgraded shotgun panels, making them vertical by removing the lower shock mounts, I'm wondering whether you have had problems with gyros.

It is my understanding that removing those shock mounts can lead to gyro problems, so I am wondering if we can get a real-world sample.  It may be a small sample size, but I would appreciate a comment if you have had gyros fail and how often.

I know many people are moving toward electronic gyros, etc. today, but I am years behind and would just like to move into the 6-pack world...so any information would be much appreciated!

Thanks in advance

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12 hours ago, chriscalandro said:

If you have standard gyros the shock mounts are required hardware. 

That would be my understanding, however, I have seen a lot of people who seem to have eliminated the bottom ones.  I am wondering how that worked out for them. If they have had gyro problems or not.

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1 hour ago, chriscalandro said:

It’s not a legal modification

I'm curious based on what do you say that it is not legal?  Perhaps it is not wise, and that is what I'm trying to ascertain.  I'm really not here to argue the legality.  I haven't seen it in the regs that an instrument panel needs to be isolated.

I could list numerous times on this web site where people have suggested removing shock mounts, I wonder how it worked out for them.  Here's a few:

 

Sadly, nobody who has done it is going to post at this point because you have made your opinion abundantly clear. 

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CCT,

You should be able to find installation instructions for your gyro instruments... or one incredibly close to it...

If you see vertical panels, it doesn’t necessarily mean their panel has gone without vibration dampers...

Sure, you can find somebody that has done it incorrectly...

Wearing out the gyro prematurely would be a typical side effect...

You can look up the cost of gyro OHs...

As far as how critical is a failed gyro... depends on if you fly in IMC... or are VFR only...

Check with your mechanic... he should be familiar with these kinds of details...

If you check with the above MSer’s hangar elf... you may not be getting a valid answer...

But, who is going to call the elf’s union to complain?
 

Apparently, Some hangar elves have more talent than others...

PP thoughts only, not a mechanic...

Best regards,

-a-

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If you don't like the lord mounts you can use a mixture of chewing gum and silly putty on the bottom instead of the screws.  It only works with juicy fruit and you have to chew it for exactly 7.37 minutes for it to blend properly with the putty.  It will hold better than the screws and you won't have that pesky angle or have to deal with more metal screws.  I'm sure there are posts about it on here so that for sure makes it ok.

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2 hours ago, chriscalandro said:

It’s in the installation instructions for most gyros I believe. There should be something about having them mechanically isolated from the frame. There’s also a circular about it. 

This is much more helpful to me than just stating that it is illegal out of hand.  I know how gyros work, I have had the opportunity to take failed ones apart.

I like doing that sort of thing.  I have searched the advisory circulars and cannot find one pertaining to this, but that does not mean there isn't one.

To find the documentation on the installation of my gyros, I would have to look pretty deep into the annals of history, they are quite old.  I am having difficulty finding a gyro manual that says that they need to be isolated, but again, that doesn't mean much.

2 hours ago, chriscalandro said:

In at least a couple of these threads there is wise advise to keep the lord mounts, which is then Ignored. It’s not opinion, it’s fact. 

I agree in principle.  If you look at at least some of those threads, I was the voice saying that keeping the lord mounts would be wise.

2 hours ago, chriscalandro said:

I don’t know why people’s questions they don’t want to hear the answer to...

I am in no way arguing that they should be removed, I was curious about statistical information.

To return to the question of legality, I have done a fair amount of tracking this down and don't find a document that pertains to this.  I found a document from the Australian CASA, which is like our FAA that recommends that we allow our aircraft to sit for 20 minutes before moving it on the ground so that we don't hurt the gyros, but later states, "Some aircraft provide a separate gyro instrument panel which is rubber shock mounted."  https://www.casa.gov.au/files/awb-31-008-issue-2-gyroscopic-instrument-reliability

 

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17 minutes ago, chriscalandro said:

If you don't like the lord mounts you can use a mixture of chewing gum and silly putty on the bottom instead of the screws.  It only works with juicy fruit and you have to chew it for exactly 7.37 minutes for it to blend properly with the putty.  It will hold better than the screws and you won't have that pesky angle or have to deal with more metal screws.  I'm sure there are posts about it on here so that for sure makes it ok.

Don't be a jerk, man.

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Most modern aircraft dont have shock mounts. If you remove the bottom shock mounts when you cut a new panel, it will sit flush at zero degrees. I am not too worried, my AI is certified for heavy vibration (helicopters) and my DG for my HSI is mounted in the back but maybe if you have older gyros they could be affected. Check install manuals or consult with your avionics shop. 

 

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