lml@lancaironline.net Mailing List Archive

Tom,

Consider this. The relationship between the horizontal and vertical stab on the 300 series is very rigid. That is, if you move the tip of the horiz up and down, the vertical willdutifully follow suit left and right. The issue you reference is really related to deflections of the tail cone ahead of the bulk head that goes up the leading edge of the vertical. Such deflections more likely occur in twist rather than vertically. The reason for this is that the strong oval shape of the tail cone is incomplete once the vertical stab starts to rise up out of the cone. Note that the two halves of the vertical stab are only held by 2 bid on the outside of the seam in this area (one cannot get to the inside if one is over 4 years old).

For racing Legacy's, Lancair wraps carbon glass around that part of the tail cone and up the vertical stab.

Another solution to add some rigidity to the 300 series tail is to flox stiff foam into the fuselage from where is starts the vertical stab rise back to the bulk head, shape the foam to follow the interior oval form and apply bids of glass or carbon over the foam and well onto the fuselage to keep the strength of the oval shape.

Scott Krueger

PS Mark Ravinsky came up with this in light of longitudinal cracks in the area that rises up from the fuselage. I added this to my airplane even though I did not perform aerobatics like Mark. Several others may have done this also.

In a message dated 2/12/2014 12:16:08 P.M. Central Standard Time, marv@lancair.net writes:

Posted for dudewanarace@yahoo.com:

So, I get a fair amount of emails through my 360 website from people
researching the 320/360 airplane. Almost always, the questions come up about
flutter, how to 'fix' it, big tail vs small tail, etc.. One of the biggest
issues I have to deal with is what is found on this page:

http://www.lancair.net/flutter.html

First let me offer my opinion on the content of that page. I know a bit
about the late Mr Hollmann and it isn't confidence inspiring. Even if his
vibration analysis was done properly, his solution really doesn't make any
sense to me. Combine that with the thousands of hours of operation without
major flutter problems that I know of, it seems all this page does is cloud
the water. Also, a back and forth banter where neither side produces a
definitive answer isn't productive, much like politics! lol

If you google "Lancair 360" it is one of the top results, probably within
the top 5. I guess my question is this: Is this page really doing any of us
any good?

As a community can we make a decision on this and either chnage/update it,
remove it, or I suppose I'm crazy and do nothing at all.

I'm all for making the tail stronger, don't get me wrong. When I finally
get the motivation to cut out my horizontal to change the incidence, I plan
on wrapping the tail just like the Super Legacy modification, given the above
average speeds I fly. Although I'm open to opinions on other ways to do
this.

Tom McNerney
http://www.N54SG.com

[First time it's come up in a number of years, however, if it's outlived its supposed usefulness I'll be happy to remove it. <Marv> ]

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