More excitement at FL 19.5 with my Rocket

[aviatoreb]

41 minutes ago, Marauder said:

 

You would also think something this critical would have a double clamp on it to prevent the scenario if one of them did fail.


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Is there any (FAA certification compliance) reason why not to put two clamps instead of one?

[Yetti]

14 minutes ago, aviatoreb said:

Is there any (FAA certification compliance) reason why not to put two clamps instead of one?

I doubt there is room to double up clamps,  I think the clamp that was on there was a cheap one, a good stainless clamp can't pull apart like that.  You strip the worm gear before they fail.  There are better clamps out there.

[Guest]

12 minutes ago, aviatoreb said:

Is there any (FAA certification compliance) reason why not to put two clamps instead of one?

Most turbocharged TCM engine induction systems have numerous clamps of this design and most work without failure of the clamp.

The most common failure I’ve seen is the maintainer does not get enough of the rubber coupling past the rolled ridge on the metal tube, the clamp is secured on the wrong side of the ridge which allows the rubber coupling to pop off of the metal tube shortly afterward.

In most cases there is not enough room for double clamping.

Clarence

[Bob]

Looks like a cheap automotive clamp.  Unfortunately after 35 years & many owners most our planes have a bit of wrong hardware.

[MIm20c]

I have clamps like that on the cold side of my turbo. They are used to attach rubber / plastic hoses to the turbo on the intake and discharge. I’m not sure if the alternative clamp shown above would have enough surface area to protect the hose. The flanges on mine are too short to double up clamps and if they were doubled more than likely they would be improperly placed. 

Worst case scenario if this clamp failed on takeoff what would the power fall to?  Could be a real problem on a short runway with high DA. 

[Rookie]

[wcb]

I basically had the same thing on my 1976 RayJay TN M20F this weekend.  I was just starting to dial in the MP and MP went from 24 to 27 stayed at 27 and then all of a sudden within less than a minute of turning on the turbo something gave an there I was back to 24 MP.  Pulled the turbo immediately back to the off position with no change and no other problems indicated on my JPI so I decided to continue my flight as planned. (for those that do not know if you turn off the turbo normalizer the plane works just as normally aspirated)  I was planning my flight at 11500 from Del Rio to Houston (if you know anything about that part of Texas I was truly in the middle of nowhere and decided to continue to 11500.  I had never climbed to 11500 without the turbo and WOW it was not good once I hit about 10000.  My cruise back just the week before gave me 201 mph TAS and 158 indicated at 13500.  This week with no turbo 160 TAS and 131 indicated.  What a big difference!

My problem seems to be the butterfly valve (my clamps seemed fine).  This is the picture of the valve.  I will be taking it in later this week and will know more.  I am thinking it is time for a full rebuild.

[Yooper Rocketman]

2 hours ago, Bob said:

Looks like a cheap automotive clamp.  Unfortunately after 35 years & many owners most our planes have a bit of wrong hardware.

To the contrary Bob.

That was a Stainless Steel High torque clamp, for which there are probably 20-25 in the intake system.  The design is not Rocket Engineering...it's the same as used on the Cessna 340's and 414's.  

I have three hose clamps below, and we see many even more expansive in design and cost on our big trucks we sell (some with spring tensioners on them too).  Few have proven to actually be any better than the simple High Torque Stainless clamp that I had fail (first one in 18 years of ownership and nearly 2000 hours flight time, with 20-25 of these clamps on just my intake system).  You will notice the High Torque has a much beefier base around the screw biting the clamp threads.  "Standard hose clamps" will fail frequently at the screw, either stripping the "threads (or cuts) in the band OR the screw base coming apart.  High Torques rarely fail here.  The more common failure on the is for the clamp to actually break.  The problem with these (and the T-bolt clamp designs) is over tightening by the installer.............clearly possible in this failure.  They are commonly tightened with a ratchet /socket combination rather than a screw driver.  We've actually seen a higher failure rate with the T bolt design in the trucking industry, as they are not easily reused.  The lock nut will stress the side loops and they eventually tear out or weaken and fail at that point.

I will stick with my High Torque Stainless clamps.  If I was to keep the plane, @Yetti had the best idea.......carry some spares.

Tom

 

[aviatoreb]

There must be some Rolls-Royce of hose clamps.  Orders of magnitude more reliable than the rest.

[Shadrach]

46 minutes ago, Yooper Rocketman said:

To the contrary Bob.

That was a Stainless Steel High torque clamp, for which there are probably 20-25 in the intake system.  The design is not Rocket Engineering...it's the same as used on the Cessna 340's and 414's.  

I have three hose clamps below, and we see many even more expansive in design and cost on our big trucks we sell (some with spring tensioners on them too).  Few have proven to actually be any better than the simple High Torque Stainless clamp that I had fail (first one in 18 years of ownership and nearly 2000 hours flight time, with 20-25 of these clamps on just my intake system).  You will notice the High Torque has a much beefier base around the screw biting the clamp threads.  "Standard hose clamps" will fail frequently at the screw, either stripping the "threads (or cuts) in the band OR the screw base coming apart.  High Torques rarely fail here.  The more common failure on the is for the clamp to actually break.  The problem with these (and the T-bolt clamp designs) is over tightening by the installer.............clearly possible in this failure.  They are commonly tightened with a ratchet /socket combination rather than a screw driver.  We've actually seen a higher failure rate with the T bolt design in the trucking industry, as they are not easily reused.  The lock nut will stress the side loops and they eventually tear out or weaken and fail at that point.

I will stick with my High Torque Stainless clamps.  If I was to keep the plane, @Yetti had the best idea.......carry some spares.

Tom

 

Were the clamps replaced when the turbo was overhauled?

[Guest]

Typical TSIO 520NB induction system.

Clarence

[Yooper Rocketman]

1 hour ago, Shadrach said:

Were the clamps replaced when the turbo was overhauled?

Some were but can’t honestly say which ones.   Chad, the A&P /IA running Kubick Aviation said he gets people all the time thinking “new” on anything airplane wise is better, yet a lot of stuff is coming from off-shore or being built “cheaper” so simply changing out parts for new does not necessarily improve reliability.  

I can attest to that in the trucking industry, as a new truck dealer AND a trailer manufacturer.  We still provide warranty repairs on new products, often.   It’s usually about half “design issues” (engineering) and half parts failures (maybe some of the same, just not the truck manufacturer).  

Chad also stated my clamp was the first one he has seen fail in 20+ years where mine failed. 

I could go over the entire plane and change a ton of parts that “might fail” but, frankly, being properly prepared, trained and informed to DEAL WITH AN ISSUE seems like a better investment to me.  Without a crystal ball, there is no way of knowing what the Aviation gods will deal me for a hand next.

Tom

[Shadrach]

1 minute ago, Yooper Rocketman said:

Some were but can’t honestly say which ones.   Chad, the A&P /IA running Kubick Aviation said he gets people all the time thinking “new” on anything airplane wise is better, yet a lot of stuff is coming from off-shore or being built “cheaper” so simply changing out parts for new does not necessarily improve reliability.  

I can attest to that in the trucking industry, as a new truck dealer AND a trailer manufacturer.  We still provide warranty repairs on new products, often.   It’s usually about half “design issues” (engineering) and half parts failures (maybe some of the same, just not the truck manufacturer).  

Chad also stated my clamp was the first one he has seen fail in 20+ years where mine failed. 

I could go over the entire plane and change a ton of parts that “might fail” but, frankly, being properly prepared, trained and informed to DEAL WITH AN ISSUE seems like a better investment to me.  Without a crystal ball, there is no way of knowing what the Aviation gods will deal me for a hand next.

Tom

I agree that parts in all industries are becomeing a crapshoot regardless of origin. I’ve paid good money for junk and also found inexpensive parts that are great. The problem is consistency. Many once respected names have been a bit dodgy in recent years...Champion, Bosch, I’ve even gotten some lousy Brembo stuff on the automotive side. I just assumed that during a turbo overhaul the installer would replace the clamps but I’m not suggesting it’s necessary.  

[LANCECASPER]

2 hours ago, aviatoreb said:

There must be some Rolls-Royce of hose clamps.  Orders of magnitude more reliable than the rest.

Who ever said that Rolls Royces were reliable?

[DonMuncy]

4 minutes ago, LANCECASPER said:

Who ever said that Rolls Royces were reliable?

They must be. I have only worked on one in my life  

[rpcc]

How can these shit clamps pass an annual inspection.   I'd hate to be trusting my life to one of those worm gear based clamps.

[xcrmckenna]

Tom,
Glad everything worked out and you made it home safe!!!


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[Guest]

RAM Aircraft in Texas has a variety of induction system clamps.

Clarence