REFLECTOR: MODIFICATIONS

[Tom Martino]

Yes ... I did a W&B ... complete and accurate.  I have an accurate empty
weight and empty C.G. ... but all of my weighing in the world cannot
tell me about the envelope established at the factory.  Center of Lift
has much to do with it.  It could be that my plane configuration has a
DIFFERENT envelope than others.  

Establishing an envelope is not done in normal W&B calculations.  The
missing factor is center of lift.  

 

-----Original Message-----
From: Jim Agnew [mailto:jim_agnew_2 at yahoo.com] 
Sent: Sunday, January 02, 2005 12:43 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: MODIFICATIONS

Didn't you have your plane weighed before inspection?  If you did you
should
have received an W&B sheet.  You should be able to calculate your new
W&B given
the new distance and weight change.  As far as the gear check with
Velocity and
see if the XL gear is heaver construction or just bigger.

If I remember correctly Alan Shaw had a Velocity with an IO-540 engine
so you
could contact him.  As far as other aircrafts data, it can be different
in
every case depending on how the bulkheads were located, location of the
seats,
the accuracy of the spars, wing shape, etc.

Jim
--- Tom Martino <tmartino at troubleshooter.com> wrote:

> PART ONE        
>  
> I re-checked with the D.A.R. that issued my Airworthiness Certificate
> ... and he verified (a second time) that I CAN make major changes to
my
> plane WITHOUT having to have another Airworthiness Inspection.  
>  
> He outlines the regs and said this is widely misunderstood.  Hey, I am
> just going with what I'm told to do.  I don't have a dog in this fight
> but I am sure happy my flight Operating Limitations (issued by him)
> gives me the authority.
>  
> He also said it is WISE to change things (like W&B) if more accurate
> numbers become available.
>  
> PART II
>  
> That brings me to Part 2 of my concern.  I am using the CG envelope
that
> other Velocity Owners are using.  My question was not where to find
the
> actual envelope ... but rather the factors that went into finding it.
> In doing so, I could determine if the conventional envelope will serve
> me with IO-540 heavier engine (hanging 7 inches longer than an IO-360)
-
> which puts my engine center of mass 3.5 inches aft of the small
engine.
>  
> In other words ... all CG envelopes are based on datums, empty
weights,
> arms and Center of Lift.  The idea is to surround the empty weight CG,
> within safe limits - while not get too far off of the center of lift -
> this is all just math.  But in order to do the math - data is needed.
>  
> That is what I meant when I said I couldn't find any data in
Velocity's
> published material.  I would think that the more info published, the
> better job builders could do.  For example ... has anyone ever tested
> the gear legs to a certain weight that breaks them upon a simulated
> landing impact?  When is beefier gear needed?
>  
> I realize e are in an experimental market ... but why re-invent the
> wheel every time we make alterations?  I am one who likes to take
> previously proven numbers and build from there.
>  
> If I could see W&B data used by Velocity, showing center of lift, etc.
> that would give me some of the info I need to move my envelope for my
> specific plane.  I am suspecting my safe envelope would be similar to
> other Elite RGs ... but the extra weight in the back would no doubt
have
> an effect.
>  
> My mission is to do a safe and effective job.  If that means major
> alterations to my Operating Manual - so be it.  I'd rather go through
> paperwork than wreckage.
>  
>  
>  
>  
>  
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=====
James F. Agnew
Jim_Agnew_2 at Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying
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