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Date: Fri, 11 May 2012 10:16:11 -0400
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Subject: RE: [LML] Re: Necessity of A/C in IV-P?
Thread-Topic: [LML] Re: Necessity of A/C in IV-P?
Thread-Index: Ac0vdD17BgfwcZEBSguNfG3GPVBnOw==
From: <bronnenmeier@GROBSYSTEMS.COM>

I just wonder why everybody wants to cut a hole in the bottom of the
fuselage? I assume most of the forces are coming from the
elevator/horizontal stabilizer in vertical direction. The most stressed
areas are the top and the bottom skin. If you put a hole in the side the
airframe should not be bothered that much (think about where a tube
breaks when you bend it).
I added an additional outside com antenna about 2 ft behind the gear
doors (works without complains now and I had already mounting holes from
a marker antenna which I eliminated). First I had the great idea of
digging into the skin and making the mounting of the antenna flush with
the airplane skin - after thinking about it some more I got scared and
left it on top of the skin.=20
My airplane has one hole in the bottom too as an air inlet for the AC -
it was already there when I got the plane - so I am going to leave it
alone but it bothers me.
For me as a non-aircraft-engineer the most appealing solution would be
what Bob suggested with one scoop on each side of the plane.

Just thinking out loud...
Ralf

-----Original Message-----
From: Hamid Wasti [mailto:hwasti@lm50.com]=20
Sent: Friday, May 11, 2012 12:05 AM
To: lml@lancaironline.net
Subject: Re: [LML] Re: Necessity of A/C in IV-P?

You can not flight test structural integrity and strength of an airframe
and live to tell about it.  Therefore Ted's original comment that flight
testing is an acceptable substitute for engineering analysis is
misinformed and naive.  Ted's subsequent comment that "A good test pilot
should be able to nibble at that edge of the envelope to identify a
flight limitation" is equally absurd in the context of structural
integrity.

A structural failure, when it happens, is likely to happen without any
warning or the opportunity to rectify things.  As I wrote earlier, the
goal of flight testing is to validate engineering analysis, not as a
substitute for it.

Regards,

Hamid


John Hafen wrote:
> Hamid:
>
> Sorry for this ignorant question:  How do you flight test the=20
> structural integrity and strength of an airframe and survive to do
anything about it?
>
> You can't bail out of an IVP.  And you would lose the plane anyway --=20
> a plane that is unique.
>
> What am I missing?
>
> John Hafen
>
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of

> Hamid Wasti
> Sent: Wednesday, May 09, 2012 10:39 AM
> To: lml@lancaironline.net
> Subject: [LML] Re: Necessity of A/C in IV-P?
>
> Ted Noel wrote:
>  =20
>> 3. Flight testing with a competent test pilot.
>>
>> I think #3 is best since it deals with the variabilities of the=20
>> installation and creates a hard VNE number.
>>    =20
> Does it? How much margin do you have? Testing is intended to validate=20
> engineering analysis, not to substitute it.
>
>  =20
>> Also, there are a lot of A/C installations flying. This implies a=20
>> degree of safety.
>>    =20
> Does it? How does your installation compare to the flying
installations?=20
> How much safety margin do they have and how much will you have? How=20
> far have they pushed their airframe (intentionally and=20
> unintentionally) and how far will you push yours?
>
> All that the flying installations indicate is that no one has done=20
> anything in their aircraft that has led to the airframe failing due to

> the modifications. Maybe there is enough margin that it has not=20
> compromised safety at all. Maybe it has cut deeply into the safety=20
> margin and there have been a lot of very close calls that no one has=20
> known about.  Without a real engineering analysis taking the big
picture in mind, no one really knows.
>
> Regards,
>
> Hamid
>
> --
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> http://mail.lancaironline.net:81/lists/lml/List.html
>
>
>
> --
> For archives and unsub=20
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>
>  =20