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Thread: tip and splitter clearance

  1. #1
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    Default tip and splitter clearance

    ... finally have engine mounted and blade length set as best as possible. However, tip clearance is 6-7mm around one side of the duct and splitter clearance is 14-15mm on one side (whole engine is slightly twisted on craft - but difficult to correct).



    Are these clearances too close for comfort ... engine, gearbox and fan are mounted on very stiff mounts.



    Any advice most welcome



    thanks

    dave

  2. #2
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    Default Re: tip and splitter clearance

    6-7mm sounds ok. Some have slightly less, but thats fine...



    Are you saying that the distance between the actual splitter plate and rotating blades is 14-15mm? If you are then this is not safe.....



    The blades flap a lot under load and you should have atleast 50mm between the rotating fan disk and the splitter....IMHO...

  3. #3
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    Default Re: tip and splitter clearance

    I agree 6-7mm tip clearance should not cause a problem.

    But the blades when under load pull forward slightly so 12-20mm clearance from the splitter will be ok.

    Too big a gap between blade and splitter plate can cause the lift air to leak back which can cause problems - depending on how sparingly your splitter plate is set!

    Hope that helps

    Derek

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    Default Re: tip and splitter clearance

    Thanks for those, quite different on splitter gap. i only ask as i can close it all up today or strip it all down and try and get a few more mm. from what you say is it my understanding that the blades, under load, can move forward? if so, when off load do they then 'over' spring back which is what my clearance is to accommadate?



    i will have a look this morning and see if i can easily get a little more clearance.



    thanks for the definative clearance on the tips though.



    much appreciated

    dave

  5. #5
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    Default Re: tip and splitter clearance

    Perhaps my 50mm was a little bit over the top.....Just flex the blades a bit and see where they are going to move to when they bend and then use your own judgement.

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    Default Re: tip and splitter clearance

    I have always run a splitter clearance of 18mm at the blade tips with no problems on a 900mm duct.

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    Default Re: tip and splitter clearance

    many thanks for all the help....



    hopefully will get it back in the sea next weekend with improved lift now everything is aligned regarding duct and splitter...



    thanks

    dave

  8. #8
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    Default Re: tip and splitter clearance

    I'm putting some vinyl cove base strip on my modified splitter (1989 Scat II), and letting the glue set, will be taking the duct tape off soon. I will then tape the edges to check for wear and to clean up the airstream.



    My understanding is you can not get too close. That under speed the blades are drawn foreward. If you plow in or stop quickly the blades are said not to whiplash backwards - I really hope this is correct.



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