From: N11TE@aol.com
Date: Wed, 21 Jul 1999 01:26:22 EDT
Subject: COZY: Structural Question

To all 3 and 4-place canard builders:

I recognize that this message may elicit some controversy.  I simply ask all 
to read and study carefully what is being presented before any flame wars are 
started.  The whole purpose is to make a better and safer plane for all of 
us, including me.

In January 1995, there was a Cozy MKIV crash in Florida.  This was clearly 
the fault of the pilot who flew too low and hooked a power line and impacted 
the ground almost directly on the nose at probably near approach speed.  The 
two in the front died but the two young men passengers in the rear seats 
survived with relatively minimal injuries.  My first reaction, after my 
sorrow that this had happened, was that I was impressed that this structure 
was strong enough to save these two.

I initially became interested in investigating this accident when I was told 
that the front seat belts did not hold.  Some members of this group will 
remember the controversy that report caused on this forum.  The response that 
I received encouraged several of us builders to go ahead and investigate much 
more thoroughly.  Since there was the potential of a law suit being filed on 
this accident, we agreed to proceed quietly so as to not become involved.  
That's why I've waited until now to bring it to everyone's attention.

As background, I received a copy of the pictures taken of the wreckage and, 
based upon questions that these pictures raised, several very experienced 
builders made a personal trip to inspect it.  It was found that yes, the 
copilot's shoulder harness bolts did pull out.  Plus, the whole center keel 
separated from the bottom and allowed both center seat belt hard points to 
pull loose.  The accident investigators told us that the two men in the front 
seats were thrown thru the canopy and instrument panel and impacted the 
ground.  They were found outside the fuselage.  One investigator even told us 
he thought they would have had a good chance to survive if the seat belts had 
held.  This, in my opinion, is pure speculation.  However, I think you can 
understand why we started by looking at the seat belt attachments.

However, the seat belt question may be only a symptom of what may be a more 
important concern.

When the whole wreckage was studied, it was found that most of the structure 
between F22 and the forward edge of the strakes simply disintegrated with 
large delamination areas in the fuselage, itself.  In other words, the bigger 
question was did the front seat belt attach system fail or did the forward 
structure fail around it?

Surprisingly, the nose from F0 to F22 simply split down the middle and half 
was found with the nose gear strut and gear still attached.  This side was 
still in almost one piece.  It apparently did not absorb any of the forces 
and allowed the area between F22 and the front of the strakes to become the 
"crumple" zone.  Unfortunately, this is where the pilot and copilot are 
located.  Apparently the forces ended up as end compressive forces on the 
fiberglass foam sandwich fuselage ... which is not designed for strength 
along this axis.

In comparison, during this investigation I talked to a number of canard 
airplane builders (including a structural engineer) who told me of specific 
accidents where they had personal knowledge of a VEZ or LEZ impacting on the 
nose at similar speeds and the nose forward of F22 absorbed the impact 
(became the crumple zone) leaving the pilot compartments intact and saving 
the lives of the pilots.  

Basically - IN MY OPINION - this indicates that the modifications made in the 
structure when it was enlarged from the LongEZ may have caused loss of 
structural strength in the area between F22 and the forward junction of the 
strakes (pilot seating area).  It very well may be only due to the change to 
a removeable instrument cover.  Mike Melville pointed out to me that Burt 
Rutan was very insistent that this cover not be made removable and stated it 
in the old Canard Pushers several times.  In other words, for full strength 
the top of the box must be closed.  Of course, the solution may involve other 
changes, too.

Before everyone gets carried away, let me point out that while this airplane 
design has never had any structural engineering review, it was built and 
tested thoroughly.  I am quite comfortable with the flying qualities.  But, 
flying stresses may be very different from crash stresses.  Even automobile 
manufacturers who have very sophisticated structural computer design software 
still go thru crash tests to determine what will actually happen in the event 
of a crash.  

This accident was one where the airframe impacted the ground head-on at 
somewhat near approach speed.  Should we say that this was a unique accident 
and will never happen again?  Or, should we look at it as an example of a 
crash that could be symptomatic of what might happen if one lost power and 
had to put down and then ran head-on into a truck, wall, rock, house, etc.?

I know, I know, the perfect solution is to never crash!

I would prefer to make the structure as safe as I can make it for me and my 
family.  To cover the event that I hope never will happen.

While we have several potential changes in mind (none that seem too difficult 
or heavy), we are not aeronautical structural engineers.  

Is there anyone on this list that has these qualifications and would be 
willing to do a structural review?  Or, do you know of any professional aero 
structural engineer who would already have some experience in canard aircraft 
construction and could be hired at a reasonable rate?

Tom Ellis
N11TE@aol.com

From: David Joelsen <DSJ@pe.dk>
Subject: RE: COZY: Structural Question
Date: Wed, 21 Jul 1999 09:02:38 +0200

Tom,

Very interesting story about the crash of a Cozy.

I have always been curious about what type of caculations went into the
design of the Cozy and other canards. However, no one doubts that the design
has plenty of safety margin, but this margin might be lost at any slight
change to the design (like altering the instrument panel or LG bulkhead).

For your information, all homebuilts in Denmark are all subject to have the
seatbelt attachment tested to 9G. Here I know that if I make a change it
will have to "survive" this test, and suddently the alteration might not be
that attractive.

Med venlig Hilsen / Best regards

David Joelsen
Sales Support, Purup-Eskofot
Phone: +45 44 73 66 73
Fax: +45 44 73 67 67

From: DougSheph@aol.com
Date: Wed, 21 Jul 1999 12:59:36 EDT
Subject: Re: COZY: Structural Question

Tom,

It's an interesting case you make, and our planes aren't going to improve if 
we never ask questions like that, but you didn't convince me of your point.

Look at it this way:  If you don't make the instrument cover removable, 
you're guaranteed to have a struggle on your hands every time you need to 
install, modify, test or repair any of your avionics.  A serious 
inconvenience on a fairly regular basis.  On the other hand, you THINK that a 
permanent cover MIGHT stiffen the fuse enough that it could save the 
occupants in a head-on collision with an immovable object at approach speed.  
If you had good reason to believe that that was true, you might have a case, 
but anecdotal incidents and idle speculation don't make a compelling point.

Design limits are what they are, and I don't think ANY plane is designed to 
preserve occupant safety in that kind of incident.  I don't think that's a 
reasonable or necessary design goal, considering the weight and cost 
increases that would be necessary.

My final point:  Suppose you put off upgrading or repairing your avionics 
because it's such a nightmare getting behind that panel without the removable 
cover.  You could wind up pancaked on a missed approach sometime.  The odds 
of that happening are probably in the same ballpark as the accident you cite. 
 The point is that the price you pay (in terms of more difficult maintenance) 
is too high, considering the payoff, in my opinion.

Doug Shepherd

From: N11TE@aol.com
Date: Wed, 21 Jul 1999 14:15:09 EDT
Subject: Re: COZY: Structural Question

Hi, Doug!

First of all, I want to thank you for your response.  You make some valid 
points.  However, it also indicates that I did a very bad job of 
communicating with you.  To a certain extent I expected that this would 
happen as it was impossible to cover all the information in one short Email.

Let me address each area separately:

In a message dated 7/21/99 12:01:02 PM Central Daylight Time, 
DougSheph@aol.com writes:

> Tom,
>  
>  It's an interesting case you make, and our planes aren't going to improve 
if 
>  we never ask questions like that, but you didn't convince me of your point.

No question but that I was only able to give a rough outline of the 
information available.  Remember that we have been studying this situation 
for several years.  Every builder to whom I have been able to present the 
whole picture in detail (including a structural engineer) has agreed that it 
needs to be investigated and changes made.

>  Look at it this way:  If you don't make the instrument cover removable, 
>  you're guaranteed to have a struggle on your hands every time you need to 
>  install, modify, test or repair any of your avionics.  A serious 
>  inconvenience on a fairly regular basis.  On the other hand, you THINK 
that 
> a permanent cover MIGHT stiffen the fuse enough that it could save the 
>  occupants in a head-on collision with an immovable object at approach 
speed. 

I did list the removeable cover as one major possibility for loss of 
structural strength.  I did not mean to imply that it was the only one.  We 
see a number of other changes that have been made which could be equally 
responsible.  I mentioned it because it was the first thing that RAF focused 
upon when I discussed it with them.

You are also assuming that there is no way to keep the benefits of the 
removeable cover but still strengthen the fuselage.
If you study the Cosy Classic, with their front-hinged canopy, you would 
notice that they may just have accomplished this goal in their design.
 
>  If you had good reason to believe that that was true, you might have a 
case, 
>  but anecdotal incidents and idle speculation don't make a compelling point.
>  Design limits are what they are, and I don't think ANY plane is designed 
to 
>  preserve occupant safety in that kind of incident.  I don't think that's a 
>  reasonable or necessary design goal, considering the weight and cost 
>  increases that would be necessary.

I do believe that there is a major problem that needs to be addressed.  I 
would not have posted this message if I did not have this confidence and the 
confirming response from a number of other builders and engineers.

>  My final point:  Suppose you put off upgrading or repairing your avionics 
>  because it's such a nightmare getting behind that panel without the 
> removable cover.  You could wind up pancaked on a missed approach sometime. 
 The odds 
>  of that happening are probably in the same ballpark as the accident you 
cite.
>  
>   The point is that the price you pay (in terms of more difficult 
maintenance)
>  is too high, considering the payoff, in my opinion.
>  
>  Doug Shepherd
 
I consider the payoff to be added family safety for which cost becomes an 
interesting viewpoint.

Again, I believe all objectives (including no more difficult maintenance) can 
be accomplished with minimal weight gain or construction problems.  We have a 
number of simple changes in mind which should solve the concerns.... but we 
are not aeronautical structural engineers.  Therefore, my original post to 
try and find such an individual.  To make sure the revisions are going to be 
done correctly.  All suggested revisions will be shared with all builders.  
As you are your own manufacturer, you have the right to use or not use them.

I would be very happy to explain the problem in much greater detail with you 
or any other builder if you want to give me a telephone call.

Tom Ellis
N11TE@aol.com

812-867-2275

Date: Wed, 21 Jul 1999 13:50:47 -0500 (CDT)
From: Tom Brusehaver <tgb@wamnet.com>
Subject: Re: COZY: Structural Question


>> a permanent cover MIGHT stiffen the fuse enough that it could save the 
>>  occupants in a head-on collision with an immovable object at approach 
>speed. 
>
>I did list the removeable cover as one major possibility for loss of 
>structural strength.  I did not mean to imply that it was the only one.  We 
>see a number of other changes that have been made which could be equally 
>responsible.  I mentioned it because it was the first thing that RAF focused 
>upon when I discussed it with them.

I think you cannot focus too much on the instrument cover either.
That would possibly strengthen things between the instrument panel and
F-22 (or F-28).  The initial post also mentioned the "structure
between F22 and the forward edge of the strakes simply
disintegrated", indicating that between the instrument panel in the
front of the strakes (couple inches) would need strength also.

Having a crush zone is a good thing. It will take lots-of-G's(TM) and
convert it into not-so-many at key places. That is the key, that the
key places have to be where the people are, and the crush zones have
to be where fixed parts of people aren't.  

I would focus more on the seat belt anchors. Let the airplane crush,
and have my feet push back (or break), but keep my body strapped to
the seat away from the crush. 

Indy and F-1 cars crash at speeds over 150mph all the time, and
drivers mostly walk away. The crush zones allow this.  

From: DougSheph@aol.com
Date: Wed, 21 Jul 1999 16:08:34 EDT
Subject: Re: COZY: Structural Question

Was said:

>Indy and F-1 cars crash at speeds over 150mph all the time, and
>drivers mostly walk away. The crush zones allow this.

Sure -- and I'm not saying that crumple zones aren't a good thing. But 
remember a few other things:
1)  Those cars also have welded steel cages to protect the driver. The cage 
and crumple zones work together for maximum effectiveness.
2)  They push their machinery to the absolute limit every time they 
race...and sometimes well beyond!
3)  They're expected to crash with some frequency -- something I hope we're 
striving to prevent.
4)  They're incredibly expensive. A few thousand bucks spent on cages and 
crumple zones means nothing to a sponsored racing team.
A more realistic comparison might be Volvo's use of the crumple zones in 
their production cars. It's not a BAD feature, I just wonder if the cost is 
really justified in terms of lives saved.

In response to Tom Ellis's further comments: If you can make my plane safer, 
at minimal cost, with no significant weight or performance penalty, go for 
it. I'm still building my plane, and I'll be the first one to incorporate 
your changes if they're legitimate. But if it costs me $20 in additional 
fiberglass/epoxy, or adds one pound to my plane, or takes me more than five 
additional hours of construction time, I'm not going to do it. You're solving 
a nearly nonexistent problem. The certain daily rewards of being one pound 
lighter are greater than the benefits of a possible solution to a 0.01% 
problem. Remember, the one incident you can point to was caused solely by 
pilot error, leading me to believe I'd be much better served to take my $20 
and five hours spare time and get 15 minutes more training time with my CFI.  
That will directly address the LEADING cause of airplane fatality (pilot 
error) and the benefits of that are undeniable.

I'm not a naysayer, just a skeptic. And I think you're chasing a mouse with a 
red Ferrari.

Doug Shepherd

Date: Wed, 21 Jul 1999 15:40:52 -0500 (CDT)
From: Tom Brusehaver <tgb@wamnet.com>
Subject: Re: COZY: Structural Question


>additional hours of construction time, I'm not going to do it. You're solving 
>a nearly nonexistent problem. The certain daily rewards of being one pound 
>lighter are greater than the benefits of a possible solution to a 0.01% 
>problem. Remember, the one incident you can point to was caused solely by 
>pilot error, leading me to believe I'd be much better served to take my $20 
>and five hours spare time and get 15 minutes more training time with my CFI.  
>That will directly address the LEADING cause of airplane fatality (pilot 
>error) and the benefits of that are undeniable.

I mostly agree with these sentiments.  This is where engineers get all
torn up. There needs to be a balance, it isn't a perfect world, how
much change can make things better. 

If the change makes the device perform poorly in some important
respect, but fixes a defect, is it worth it. 

The airplane might be made safer by attatching a parachute system to
it, Cirrus is trying this (and other features).  Will the extra cost
every be tested, or prove better?  The Jury is still out, it has
worked for smaller lighter airplanes, evidence says it will help.

Airbags could have saved lives in cars before they were put in. Once
they were put in, they actually had another defect hurting and killing
short people (kids mostly).  It seemed like the right thing to do, but
until someone tested it, the full effects of the change were not
realized.

Date: Wed, 21 Jul 1999 14:25:35 -0700
From: Stefan G Siegel <stefan@u.arizona.edu>
Subject: Re: COZY: Structural Question

While I understand the desire to improve the design towards more 
safety,  I would like to point out that it is not as easy as just 
hiring "someone who knows about those things" for a couple of hours, 
as suggested:

At 1:26 AM -0400 7/21/99, N11TE@AOL.COM wrote:
>
>Is there anyone on this list that has these qualifications and would be
>willing to do a structural review?  Or, do you know of any professional aero
>structural engineer who would already have some experience in canard aircraft
>construction and could be hired at a reasonable rate?


Being the targeted aerospace engineer and having done structural 
composite design, here are my two cents worth:

1. If you strengthen the structure, you do *not* necessarily improve 
the crash safety. In the described accident for example , a stronger 
fuselage might have killed all occupants because it would have 
decelerated the airplane faster, thus increasing the g loading on all 
occupants. Your body can only withstand a certain amount of 
acceleration, if this is exceeded, you are being seriously injured.

2. To figure those things out, the car industry undertakes countless 
crash tests on top of computer simulations. During the course of 
these tests, the structure is often deliberately _weakened_ in 
certain spots to _improve_ the crash behavior. Also, you always have 
to make compromises during this optimization. You gain in certain 
type crashes by a certain modification, but in other type crashes 
this modification might make things worse. In order to make decisions 
on design improvements, you need not only know what failed during a 
crash (by looking at the wreckage), it is also crucial in which order 
things failed, and most importantly, what the accelerations and 
movements of the persons (dummies) involved were like during the 
crash.

Having said all this, I do not think that one can make sound 
engineering conclusions as to how to improve the design from the 
observations described in the original post, with one exception. In 
all crashes it seems to be beneficial to keep the occupants inside 
the vehicle at all cost. Therefore, improving the seat belt attach 
points should be a sure means to improve the crash worthiness.  As 
far as strengthening the fuselage goes, chances are high that this 
will cause more additional problems than it will solve.

None of us will be able to afford the testing necessary to make sound 
structural improvements towards more crash safety to the design. 
While designing a structure to take the loads encountered while the 
structure is intact is enigineering wise relatively simple, it is 
very difficult to predict how it will behave when parts of it start 
to fail. It would require another type of NASA program funding this 
undertaking, in the same way as they brought the AGATE program into 
life.

Stefan

---------------------------------------------------------------------------
Stefan Siegel		       email: stefan@u.arizona.edu
2813 E Elm Street              http://venus.ame.arizona.edu/~fury/
Tucson, AZ 85716, USA

Phone: (520) 321-9217          Long Ez N234BW, hangared at KRYN
---------------------------------------------------------------------------

From: cdenk@ix.netcom.com
Date: Wed, 21 Jul 1999 21:12:52 -0500 (CDT)
Subject: Re: COZY: Structural Question

Stefan said <Being the targeted aerospace engineer and having done structural composite design, 
here are my two cents worth:>

I concur with his remarks. But

I wish more pilots would pay attention to the details of safety of flight.

1: Equipment - All complaints get fixed promptly.
2: Attitude - Listen to others, seek advice. Landed at Pueblo Co. once. A local asked where we 
were headed, I indicated going diect Page, Az. He suggested a slightly different route, which 
would keep us closer to civilization. Thats what we did the next day.
3: Always get a standard weather briefing, unless very local flight. If using DUATS and weather 
is not super, talk to a briefer before departing, he may have some trends, insight and words 
that weren't obvious with the dumb computer. If "VFR flight not recommended", think twice, 
consider alternatives. Consider what risks are added with that comment. i.e. I will under some 
conditions go if its say less than 20 miles of ground fog, with clear above. The risk I accept 
is if a forced landing is required, I won't be able to see to select a good landing site. But I 
will carry additional altitude, possibly enough to glide to a clear area.
4: File a flight plan. This has 4 advantages
	a: Forces some planning and thought of whats ahead
	b: Someone will try to give you a weather briefing, which includes pireps and notams  
	c: Of course notification of search and rescue.
	d: Make position reports, I usually do 1 per hour, more frequently if flight conditions 
		are not great. Briefer will update weather. THis worked great once going in to 
		Jackson,Wy., where we learned of a recently issued thunderstorm watch, and with a 
		discussion with the briefer, found a neat place for the night.
5: I don't fly at night over unfamiliar terrain, that is more than about 100 miles from home, 
don't accept the added risk of electrical failure (never had one), or forced landing, within 
known terrain, I carry extra altitude and probably could make it to an airport or road that I 
know well.
6: No night IFR (or near), do not accept risk of electrical failure, and trying to navigate, fly 
plane, while holding flashlight in mouth.
7: No continous flight in any icing, may with much thought do an easy approach through a thin 
layer or 2, with enough fuel to get to clear conditions.
8: No flight with possible thunderstorms anywhere near, unless able to get high in the clear 
with excellent visibility and see possible storms. And then stay in the clear!


This is only a few of the major items that go into my Go/No Go decision. THe idea is minimize 
the risk, when several items happen together, its time to land. Way home from OSH, it was 3 
strikes, and land: sun setting, tired, couldn't read the identifier for Grand Rapids on the  
chart fold. We had planned on Grand Rapids for the night, landed at Muskegon, Mich. The bonus 
the next morning was tower said they had never see a plane like ours, could we offset toward the 
tower after lift off, we did  a 45 degree bank at about a 200' radius around the tower at their 
elevation (buzzed the tower) and got thanked!

Has anyone heard that well know fatality recently even did something free, and takes only a few 
minutes, like a standard briefing?

Date: Wed, 21 Jul 1999 22:57:34 -0600
From: James Russell <fshort@flash.net>
Subject: Re: COZY: Structural Question

>>> a permanent cover MIGHT stiffen the fuse enough that it could save the
>>>  occupants in a head-on collision with an immovable object at approach
>>speed.
>>
>>I did list the removeable cover as one major possibility for loss of
>>structural strength.  I did not mean to imply that it was the only one.  We
>>see a number of other changes that have been made which could be equally
>>responsible.  I mentioned it because it was the first thing that RAF focused
>>upon when I discussed it with them.
>
>Having a crush zone is a good thing. It will take lots-of-G's(TM) and
>convert it into not-so-many at key places. That is the key, that the
>key places have to be where the people are, and the crush zones have
>to be where fixed parts of people aren't.
>
>I would focus more on the seat belt anchors. Let the airplane crush,
>and have my feet push back (or break), but keep my body strapped to
>the seat away from the crush.
>
>Indy and F-1 cars crash at speeds over 150mph all the time, and
>drivers mostly walk away. The crush zones allow this.

Hi all:

	This is certainly a good discussion - even though I hope no one has to
benefit from it during an impact...

	Racing cars are tanks when compared to aircraft - because they crash
alot ( compared to A/C ) - I have a section of a March Indy car tub: .250"
of uni- and bi-directional carbon. Compared to the old sheetmetal tubs,
composite cars are much stronger overall ( esp. in torsion ) and lighter.

	But, composites fail by fracturing vs. bending for sheetmetal (
remember the flood-damaged Pipers that NASA? crash-tested and saw the huge
temporary deflection of the fuselage top almost hitting the seats? ). I
have seen carbon racing car noses fail completely @ the dash bulkhead
leaving the driver's feet hanging out.

	Rule-making bodies have been moving the driver( and his feet ) back
to provide the room to absorb the impact and most composite tubs use Al
honeycomb ( the cells aligned w/ the cars' centerline ) to provide crush
space in the nose. I plan to include core aligned up-to-down under the
seats to help w/ compression
fractures...

	If the harness mounts are failing before the surrounding structure,
then I will share the engineer's cost to review them - please email me.
Harness attach point failures are vanishingly rare in racing cars. You (
and the belts )
will strech an amazing amount under load - one of my drivers hit a wall and
his helmet impacted a mirror mount 34" away!

	I certainly know it is easy to get fixiated on one concept and not view
the entire package - I do it all the time! I also am very aware that any design
is a necessary mass of compromises - the unbreakable 14 lb. steel
snowshovel that you can't lift comes to mind.

	 I am very glad that Nat "ported" the VZ/LZ design over to four
places. I was tired of being crammed into racing car cockpits designed for
150 lb., 5' 6" drivers...So, having more panel space, getting to see your
"copilot" (thanks, Shirley!), real luggage space, occasional 4 person
trips, etc. are all the reasons I am going to build a Cozy.

Regards,
James





From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Stress calculations
Date: Wed, 1 Dec 1999 12:10:43 -0600

Builders,
Burt Rutan told me that he supplied stress calculations to all foreign
countries requesting it for the Long EZ, and he probably also supplied the
confirming static tests. He told me that for the 3-place Cozy (We are a
licensee) to tell these countries to use the same information as he
supplied for the Long EZ. In the Mark IV, because of its higher gross (even
though Long EZs have been operated at a higher gross than the Mark IV), we
increased the spar cap thickness by 20% and added other reinforcements in
critical areas, and lowered the category to "normal" from "utility", mostly
because we wished to discourage aerobatics in a family cross country
airplane. Most accidents in Long EZs were caused (in our judgement) by
reckless behavior. My information is that Burt designed the Long EZ wings
to 12+gs, the centersection spar to 18gs, and the canard to 14+gs and these
were confirmed by static testing. The "normal" category is limited to 3.8
gs, and I doubt if we have seen more than 2 gs in normal operation.
Regards,
Nat
PS: There are no know cases where either a Long EZ or a Cozy, built per
plans and operated within critical limits, has come apart in the air.

Date: Wed, 01 Dec 1999 18:50:32 -0800
From: "J. D. Newman" <infaero@flash.net>
Subject: COZY: Re: Stress calculations

> Nat Puffer wrote:

> My information is that Burt designed the Long EZ wings to 12+gs, the
> centersection spar to 18gs, and the canard to 14+gs and these were confirmed
> by static testing.

    Based on a 1325 lb. gross weight Long-EZ.

Date: Tue, 14 Dec 1999 10:32:56 -0500 (EST)
From: Richard William Crapse <rwcrapse@unity.ncsu.edu>
Subject: COZY: G-loading comparisons 


Ok guys, 

	I tripped across the discussion of normal versus utility category
because of the higher Gross weights.

So here is what I did in Excell:

Long EZ:
Wings     12g * 1325 lbs. = 15900
Canard    14g * 1325 lbs. = 18550
Spar      18g * 1325 lbs. = 23850
(Assumption: 1325 lbs. is gross weight of Long EZ)

Cozy:
Wings     15900 / 2050 lbs. = 9 G
Canard    18550 / 2050 lbs. = 7.75 G
Spar      23850 / 2050 lbs. = 11.6 G

Heavy Cozy:
Wings     15900 / 2150 lbs. = 8.6 G
Canard    18550 / 2150 lbs. = 7.4 G
Spar      23850 / 2150 lbs. = 11.1 G

Assumptions for Cozy and Heavy Cozy:
1. Does not take into account upgraded spars or wings.
2. Uses published numbers from Rutan for analysis.
3. Pilot could inflict such loads under normal flight or control inputs.
4. Same style of attachment for engine mounting.
5. Original user typed correctly and excel does correct math.

Rick
Cozy #706
(1 flood, six hurricanes, and more miles on the road than most GA aircraft 
fly in one year, .... the joys of homebuilding)


'All the power in the Universe, but an itty,bitty,little living space'----
                                                         Aladin(genie)
'If it 's got wings, I'll fly it'--Pilot

'And let me know when Elvis shows up...'----Beldar Conehead

'If a shoebox had wings, I'd make it fly!'---The Rocketeer


