GA piston engines - Cylinder Girdles
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Joined: Jul 2003
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From: Oz
GA piston engines - Cylinder Girdles
Recently i was watching a slow motion video that was showing a 6 cylinder GA engineat full power and was quite amazed to see the cylinders waving around like leaves in a wind. The amount of movement was quite stagering.
There is a company that claims to have a fix for this. Where they have the rocker covers for all cylinders on each each side as one very solid unit and then have a number of cross brace bolts tying the oposite sides together, much like a strut brace a car.
They claim its very effective in making the engine much more rigid in very high power aerobatic operations, but would it pay any dividends on normal stock engines, especialy in terms of reliability.
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There is a company that claims to have a fix for this. Where they have the rocker covers for all cylinders on each each side as one very solid unit and then have a number of cross brace bolts tying the oposite sides together, much like a strut brace a car.
They claim its very effective in making the engine much more rigid in very high power aerobatic operations, but would it pay any dividends on normal stock engines, especialy in terms of reliability.
The premier manufacturer of performance aircraft exhaust systems and engine components.
Joined: Feb 2009
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From: Austria
Sounds interesting - but actually, what is the necessity behind such an addition? The engine should be designed to withstand those vibrations also without those additional struts and braces; tying parts together that are not meant to would change the vibration patterns and possibly induce loads on parts that were not meant to bear them. Compare an unbraced cylinder moving like a reed (hinged on one side) vs. a braced one vibrating like a string (hinged on both sides) - the bending moments seem rather different.
Joined: Feb 2000
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From: Alaska, PNG, etc.
Sounds interesting - but actually, what is the necessity behind such an addition? The engine should be designed to withstand those vibrations also without those additional struts and braces; tying parts together that are not meant to would change the vibration patterns and possibly induce loads on parts that were not meant to bear them. Compare an unbraced cylinder moving like a reed (hinged on one side) vs. a braced one vibrating like a string (hinged on both sides) - the bending moments seem rather different.
It's worth noting that nowhere on that site could I find any reference to an STC for the modification. That would lead me to believe that there isn't one, which means it's for experimental aircraft only.
Joined: Apr 2012
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From: Seattle, WA
The aircooled Porsche 911's have no issues with the cylinder heads on each bank tied together by the cam carrier.
Pretty obvious from the link that they are primarily for use on highly modified non certified engines.
Pretty obvious from the link that they are primarily for use on highly modified non certified engines.
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From: Alaska, PNG, etc.
Originally Posted by bcgallacher
Lycoming and Continental engines have hydraulic tappets in the valve train which keep the valve clearances at zero - they are self adjusting during every opening/closing cycle.
