COZY: broken airflow elbow


Bill Allen
 


In the UK, where there is no “Experimental” category available to individual builders (there is, if you are, for example Rolls Royce - but thats another story…) our CAA (UK FAA) delegates approval for homebuilts to the Light Aircraft Association (LAA) who have responsibility for issuing “Permits to Fly”.

 The LAA have a network of inspectors and procedures for approving “modifications” and when I fitted my AFP unit back in 2000, an inspector came to inspect the installation.
He saw the AFP unit cantilevered off the sump and would not approve the installation without additional support, on the grounds that this vibrating cantilevered mass could fatigue the 90deg adapter, causing “stress relieving fissures” (cracks) resulting in engine failure.

I argued against this as “gold plating” of requirements, and adding unnecessary weight and complexity etc but he was firm that he wouldn’t sign it off without additional bracing - you can see the 2 white tubes from the brace that was eventually fitted between the sump and the AFP unit in the attached pics.

Maybe my in the light of Marcs’ experience, the Inspector wasn’t so wrong…… having said that, my installation has done 500hrs in 20yrs versus Marcs’ 1100hrs, so without bracing maybe it would have lasted another 20 years…..

Best to all,

Bill Allen




On Wed, 17 Aug 2022 at 17:53, vance atkinson <nostromo56@...> wrote:

Marc  (you are one lucky SOB that the engine kept running...GOOD job, hope you luck-bucket is not empty)

All..

I was one of the first ones if not the first to use Don's Airflow Performance  fuel injection sys. on my cozyIII Lyc 0320.  Yes we had some problems. I trashed two units Due to excessive engine vibrations.  To me it ran smooth, but pretty soon it wouldn't idle correctly and sent it back.  Don sez the diaphragm and needle seat were trashed, he fixed it for free.   Then it happened again, and he fixed it for free.  The third time it happened he said cant keep doing this..He explained he had to calibrate the whole system after replacing the parts.  I said as far as what I could feel in the air-frame, it ran smooth.

So you will notice in the picture there is a rubber isolator he came up with and it solved the problem.  I think that Marc's view of the whole unit cantilevered out the way it is caused part of the problem, if not all.  I have had the system as shown for over 2200 hours and still going.  You might notice the aluminum spacer I used to lower the whole arraignment.  Being a critical component I had a certified welding shop make it and I checked it for cracks frequently...for years, less as time went on. It's still holding up.  I see Don is making all sorts of adapters and extenders now.

Sorry to hear you got the last casting on earth Marc.  For that problem I have one that fits the Lyc 0360 that I've had for years and am pretty sure I wont be needing it.  Will sell it, if anyone needs one or a spare.  Picture is below with measurements,  Call or Email

Vance Atkinson

817 296 1940


 




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Ryszard Zadow
 

< Maybe my in the light of Marcs’ experience, the Inspector wasn’t so wrong…>

Ya think? 

Most Bendix type throttle body’s, especially on 
Lycoming, are bolted to something incredibly solid like an oil sump. The attached pic is how we hung the throttle body on the Viggens cold air induction. I’d be leery of anything that heavy being stuck out on an arm and allowed to shake. 

image0.jpegimage1.jpeg


On Aug 18, 2022, at 03:23, Bill Allen <billallensworld@...> wrote:



In the UK, where there is no “Experimental” category available to individual builders (there is, if you are, for example Rolls Royce - but thats another story…) our CAA (UK FAA) delegates approval for homebuilts to the Light Aircraft Association (LAA) who have responsibility for issuing “Permits to Fly”.

 The LAA have a network of inspectors and procedures for approving “modifications” and when I fitted my AFP unit back in 2000, an inspector came to inspect the installation.
He saw the AFP unit cantilevered off the sump and would not approve the installation without additional support, on the grounds that this vibrating cantilevered mass could fatigue the 90deg adapter, causing “stress relieving fissures” (cracks) resulting in engine failure.

I argued against this as “gold plating” of requirements, and adding unnecessary weight and complexity etc but he was firm that he wouldn’t sign it off without additional bracing - you can see the 2 white tubes from the brace that was eventually fitted between the sump and the AFP unit in the attached pics.

Maybe my in the light of Marcs’ experience, the Inspector wasn’t so wrong…… having said that, my installation has done 500hrs in 20yrs versus Marcs’ 1100hrs, so without bracing maybe it would have lasted another 20 years…..

Best to all,

Bill Allen


5221A57A-C0E5-4D75-8BC0-D55B86DE1782.jpeg


On Wed, 17 Aug 2022 at 17:53, vance atkinson <nostromo56@...> wrote:

Marc  (you are one lucky SOB that the engine kept running...GOOD job, hope you luck-bucket is not empty)

All..

I was one of the first ones if not the first to use Don's Airflow Performance  fuel injection sys. on my cozyIII Lyc 0320.  Yes we had some problems. I trashed two units Due to excessive engine vibrations.  To me it ran smooth, but pretty soon it wouldn't idle correctly and sent it back.  Don sez the diaphragm and needle seat were trashed, he fixed it for free.   Then it happened again, and he fixed it for free.  The third time it happened he said cant keep doing this..He explained he had to calibrate the whole system after replacing the parts.  I said as far as what I could feel in the air-frame, it ran smooth.

So you will notice in the picture there is a rubber isolator he came up with and it solved the problem.  I think that Marc's view of the whole unit cantilevered out the way it is caused part of the problem, if not all.  I have had the system as shown for over 2200 hours and still going.  You might notice the aluminum spacer I used to lower the whole arraignment.  Being a critical component I had a certified welding shop make it and I checked it for cracks frequently...for years, less as time went on. It's still holding up.  I see Don is making all sorts of adapters and extenders now.

Sorry to hear you got the last casting on earth Marc.  For that problem I have one that fits the Lyc 0360 that I've had for years and am pretty sure I wont be needing it.  Will sell it, if anyone needs one or a spare.  Picture is below with measurements,  Call or Email

Vance Atkinson

817 296 1940


 



dm9HJ74U4efN16Q3.png

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