carbon


Jim Staud <staudjf@...>
 

If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing upgrade in the Q-Talk 127 Photos. The revised main wing has noticeable carbon strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed to the cylindrical carbon spar. What were the results of that experiment and waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.


Sam Hoskins
 

Jim, there is no all carbon Q.

I don't have any carbon in my main wing. The main wing uses standard UNI
glass, not BID. In preparation for the layups, I draw 45 degree lines on
the foam cores, to help ensure proper alignment of the two first layers, per
plans. Perhaps, that is what you are confusing,

The only change I made to the new wing was to add one proportionately sized
spar cap.

Sam


On Wed, Dec 16, 2009 at 10:23 PM, Jim Staud <staudjf@...> wrote:



If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to
stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing upgrade
in the Q-Talk 127 Photos. The revised main wing has noticeable carbon
strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed to
the cylindrical carbon spar. What were the results of that experiment and
waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce
landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.

[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]


One Sky Dog
 

Jim,

Carbon should only be used where its properties are better than other
materials it is not the magic material.

If you mix carbon with glass the carbon will take all the load and the
glass will be loafing along not taking any load. This is because the glass
streches a lot easier than carbon. It is like gluing a rubber band to a steel
bar the bar takes all the load before the rubber can move let alone pick up
some of the load.

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.

Best to follow the plans unless you are a qualified design engineer.

Regards,

Charlie Johnson

In a message dated 12/17/2009 4:52:55 A.M. Mountain Standard Time,
staudjf@... writes:

If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to
stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing upgrade
in the Q-Talk 127 Photos. The revised main wing has noticeable carbon
strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed to
the cylindrical carbon spar. What were the results of that experiment and
waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce
landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.


One Sky Dog
 

Sorry Larry,

I just checked it is back down to $50.00 a yard.

So what is your point? I think I was talking about using the right material
for the right job. Do you have any constructive input or are you just
trolling?

Regards,

One Sky Dog 550 hrs in 1 Dragonfly


In a message dated 12/17/2009 6:22:17 P.M. Mountain Standard Time,
larry2@... writes:


Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.
Source??? If I could get anyone to pay that, I would go into
business. 100-300% is a great return on the investment.


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...



------------------------------------

Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links


Larry Severson
 

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.
Source??? If I could get anyone to pay that, I would go into business. 100-300% is a great return on the investment.


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...


Seeadler18 <marko.rocznik@...>
 

Yes - you are absolutely right. Thats why I do not understand the discussion about the carbon spar for the Q1 canard. If you put a carbon spar in there, then at least all the UNI has also to be made out of carbon. So eigther everything is build in carbon or nothing.

Another point is, how an all carbon Q1 canard would work in terms of landing behavoir. I belief that springs in the gear would be needed since the carbon wing wouldn't flex anymore. Also the connection to the fuselarge would be more stressed..

I wonder what Rutan would have done if he had carbon available back in the days....

Marko

--- In Q-LIST@..., oneskydog@... wrote:

Jim,

Carbon should only be used where its properties are better than other
materials it is not the magic material.

If you mix carbon with glass the carbon will take all the load and the
glass will be loafing along not taking any load. This is because the glass
streches a lot easier than carbon. It is like gluing a rubber band to a steel
bar the bar takes all the load before the rubber can move let alone pick up
some of the load.

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.

Best to follow the plans unless you are a qualified design engineer.

Regards,

Charlie Johnson

In a message dated 12/17/2009 4:52:55 A.M. Mountain Standard Time,
staudjf@... writes:

If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to
stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing upgrade
in the Q-Talk 127 Photos. The revised main wing has noticeable carbon
strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed to
the cylindrical carbon spar. What were the results of that experiment and
waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce
landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.





Patrick Panzera <panzera@...>
 

The carbon spar takes the bending loads.
The glass takes the torsional loads, laid up 45 degrees to the spar.
Together they make for a strong wing.

Making the skin from carbon, with a carbon spar, would not add any stiffness
to the landing dynamics, unless it was laid-up to do so.

Rutan certainly had carbon back then but like now, it was too expensive as
compared to glass.

Pat

Yes - you are absolutely right. Thats why I do not understand the
discussion about the carbon spar for the Q1 canard. If you put a carbon
spar in there, then at least all the UNI has also to be made out of
carbon. So eigther everything is build in carbon or nothing.

Another point is, how an all carbon Q1 canard would work in terms of
landing behavoir. I belief that springs in the gear would be needed since
the carbon wing wouldn't flex anymore. Also the connection to the
fuselarge would be more stressed..

I wonder what Rutan would have done if he had carbon available back in the
days....

Marko


Robert Cringely
 

I'm working on an all-carbon Q1. It is intended for high altitude cruising so the carbon (100 percent carbon, except where internal antennas are placed) is there strictly to increase flutter resistance. The engine is a normally-aspirated 2275 flywheel drive from Great Plains. With no starter, nikasil aluminum cylinders and a pair of Bing carbs the engine weighs 140 lbs and can be mounted two inches from the (shifted back) firewall. I'll get 40 hp at 17,999 feet, which should be good for about 204 KTAS. An extra eight gallon tank will be behind the seat. Range will be four hours plus reserve. I plan to move the gear inboard like a Dragonfly Mk II and take the anhedral out of the canard. This will be my seventh homebuilt and third with VW power. It's replacing the Glasair TD I flew for 29 years before becoming a Dad late in life. My family plane is a Cirrus VK-30.

Bob


On Dec 17, 2009, at 8:46 PM, oneskydog@... wrote:

Sorry Larry,

I just checked it is back down to $50.00 a yard.

So what is your point? I think I was talking about using the right material
for the right job. Do you have any constructive input or are you just
trolling?

Regards,

One Sky Dog 550 hrs in 1 Dragonfly


In a message dated 12/17/2009 6:22:17 P.M. Mountain Standard Time,
larry2@... writes:

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.
Source??? If I could get anyone to pay that, I would go into
business. 100-300% is a great return on the investment.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...

------------------------------------

Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links





[Non-text portions of this message have been removed]


Larry Severson
 

I just checked it is back down to $50.00 a yard.

So what is your point? I think I was talking about using the right material
for the right job. Do you have any constructive input or are you just
trolling?
Carbon has a place. It is 3+ times stiffer for a given weight. In the use that I will be making, pultruded carbon rods can provide 280,000 psi in tension and 320,000 psi in compression. However, you are correct, for hand layup, it is very difficult to insure saturation of the fabric with epoxy. Almost all who use carbon fiber do it with vacuum bagging, or even better vacuum infusion. If the Q had been designed with CF spar caps, the plane would be both lighter and stronger. The time to build would have also been significantly reduced. But, what we know now is not what was known in 1980.

None of which involves "building to plans".

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...


Allan Farr
 

Would it be feasible to pressurize?
Allan

----- Original Message -----
From: "Robert X. Cringely" <bob@...>
To: <Q-LIST@...>
Sent: Friday, December 18, 2009 6:20 PM
Subject: Re: [Q-LIST] carbon


I'm working on an all-carbon Q1. It is intended for high altitude cruising so the carbon (100 percent carbon, except where internal antennas are placed) is there strictly to increase flutter resistance. The engine is a normally-aspirated 2275 flywheel drive from Great Plains. With no starter, nikasil aluminum cylinders and a pair of Bing carbs the engine weighs 140 lbs and can be mounted two inches from the (shifted back) firewall. I'll get 40 hp at 17,999 feet, which should be good for about 204 KTAS. An extra eight gallon tank will be behind the seat. Range will be four hours plus reserve. I plan to move the gear inboard like a Dragonfly Mk II and take the anhedral out of the canard. This will be my seventh homebuilt and third with VW power. It's replacing the Glasair TD I flew for 29 years before becoming a Dad late in life. My family plane is a Cirrus VK-30.

Bob


On Dec 17, 2009, at 8:46 PM, oneskydog@... wrote:

Sorry Larry,

I just checked it is back down to $50.00 a yard.

So what is your point? I think I was talking about using the right material
for the right job. Do you have any constructive input or are you just
trolling?

Regards,

One Sky Dog 550 hrs in 1 Dragonfly


In a message dated 12/17/2009 6:22:17 P.M. Mountain Standard Time,
larry2@... writes:

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.
Source??? If I could get anyone to pay that, I would go into
business. 100-300% is a great return on the investment.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...

------------------------------------

Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links



One Sky Dog
 

Just bring money and time.

Charlie

In a message dated 12/18/2009 1:14:58 A.M. Mountain Standard Time,
afarr@... writes:

Would it be feasible to pressurize?
Allan


Robert Cringely
 

Not without 1-2 more layers of carbon and a much thicker canopy with a different type of multi-point latch. The weight would probably go up by 50 percent. You'd also need a turbocharger to provide the pressure. Personally I see no need to pressurize for those mid-teen altitudes but would want to do it if I was aiming for the mid-twenties. However that would require IFR equipment I think you'd have a hard time finding room for in a Q1. It would be better to start with a clean sheet of paper for a pressurized model, which would have much more of a round fuselage cross-section.

The only reason I'm going with carbon is to make the structure stiffer and raise the flutter limits.


Bob

On Dec 18, 2009, at 3:14 AM, Allan Farr wrote:

Would it be feasible to pressurize?
Allan

----- Original Message -----
From: "Robert X. Cringely" <bob@...>
To: <Q-LIST@...>
Sent: Friday, December 18, 2009 6:20 PM
Subject: Re: [Q-LIST] carbon

I'm working on an all-carbon Q1. It is intended for high altitude cruising
so the carbon (100 percent carbon, except where internal antennas are
placed) is there strictly to increase flutter resistance. The engine is a
normally-aspirated 2275 flywheel drive from Great Plains. With no starter,
nikasil aluminum cylinders and a pair of Bing carbs the engine weighs 140
lbs and can be mounted two inches from the (shifted back) firewall. I'll
get 40 hp at 17,999 feet, which should be good for about 204 KTAS. An extra
eight gallon tank will be behind the seat. Range will be four hours plus
reserve. I plan to move the gear inboard like a Dragonfly Mk II and take
the anhedral out of the canard. This will be my seventh homebuilt and third
with VW power. It's replacing the Glasair TD I flew for 29 years before
becoming a Dad late in life. My family plane is a Cirrus VK-30.

Bob

On Dec 17, 2009, at 8:46 PM, oneskydog@... wrote:

Sorry Larry,

I just checked it is back down to $50.00 a yard.

So what is your point? I think I was talking about using the right
material
for the right job. Do you have any constructive input or are you just
trolling?

Regards,

One Sky Dog 550 hrs in 1 Dragonfly


In a message dated 12/17/2009 6:22:17 P.M. Mountain Standard Time,
larry2@... writes:

Economics is also a big factor with dry carbon cloth over one hundred
dollars a yard.
Source??? If I could get anyone to pay that, I would go into
business. 100-300% is a great return on the investment.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...

------------------------------------

Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links






Mike Perry
 

Earlier Charlie wrote " Carbon should only be used where its properties are better than other materials it is not the magic material. . . . Best to follow the plans unless you are a qualified design engineer." and now "Just bring money and time." Absolutely!

You are talking about a total redesign of the Q type aircraft. Please don't assume these substitutions are simple. It is actually easy to make one part too strong so the load is concentrated in another part of the structure. There will be an article in the next Q-Talk that will explain exactly how I did that (in a test wing, not a flying airplane).

Earlier Jim Staud wrote: "If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to stress test it, and what were the results?" I would add, don't fly in one that had these kind of mods and wasn't stress tested.

This entire discussion belongs on Q-Performance.

Mike Perry

oneskydog@... wrote:


Just bring money and time.

Charlie


In a message dated 12/18/2009 1:14:58 A.M. Mountain Standard Time,
afarr@... <mailto:afarr%40ihug.co.nz> writes:

Would it be feasible to pressurize?
Allan



Leon
 

In the
use that I will be making, pultruded carbon rods can provide 280,000
psi in tension and 320,000 psi in compression.
I do believe that you have your numbers backwards? Nice to know that I'm not the only dyslexic Q builder :-)

If the Q had been
designed with CF spar caps, the plane would be both lighter and
stronger. The time to build would have also been significantly
reduced.

Maybe not. My carbon rod LS-1 Quickie canard weighs virtually the same as my per plans GU canard. The cores were more "dog boned" than I would have liked and I did not vacuum bag. I also used more material than needed so I wouldn't have to do as much fabric cutting. I'm guessing that if I used perfect cores, optimized the skin layup schedule and vacuum bagged I might be able to shave off 5 or 6 pounds.

As for time involved I'd say that it was about the same (not counting design time). If I were to do a second I could make some more user friendly jigs to speed things up a bit.

My carbon rod canard IS considerably stiffer. Stronger? I'd have to test each to destruction to be sure. I don't plan to do so.

Price from AS+S for the rod I used, as of last night, was a touch over $300.
=========================
Leon McAtee


Robert Cringely
 

I'm not sure I agree with this statement. I get your point about changing materials moving around the stress concentrations, but what you describe is much more of a problem with heterogeneous use of materials -- adding carbon parts here and there. An ALL-CARBON Q1 should carry its loads exactly like an ALL-GLASS Q1. Yes, there is the prospect of loads rising some on certain metal fittings because of the greater stiffness and possibly the higher speeds, but this is a minor percentage of the total weight of hte airframe and can be handled fairly easily by moving up a gauge or two in metal thickness and using more robust fasteners.

Bob


On Dec 18, 2009, at 11:12 AM, Mike Perry wrote:

Earlier Charlie wrote " Carbon should only be used where its properties
are better than other materials it is not the magic material. . . .
Best to follow the plans unless you are a qualified design engineer."
and now "Just bring money and time." Absolutely!

You are talking about a total redesign of the Q type aircraft. Please
don't assume these substitutions are simple. It is actually easy to
make one part too strong so the load is concentrated in another part of
the structure. There will be an article in the next Q-Talk that will
explain exactly how I did that (in a test wing, not a flying airplane).

Earlier Jim Staud wrote: "If they did build an all carbon Q1, Q2, Q200,
or TRI-Q, were they able to stress test it, and what were the results?"
I would add, don't fly in one that had these kind of mods and wasn't
stress tested.

This entire discussion belongs on Q-Performance.

Mike Perry

oneskydog@... wrote:


Just bring money and time.

Charlie


In a message dated 12/18/2009 1:14:58 A.M. Mountain Standard Time,
afarr@... <mailto:afarr%40ihug.co.nz> writes:

Would it be feasible to pressurize?
Allan




[Non-text portions of this message have been removed]


Jim Staud <staudjf@...>
 

Sam,

Is that the standard layup using only uni?

Are there any knowledgeable owners like yourself in the Dallas / Ft. Worth area and venues to meet them?

Jim Staud




________________________________
From: Sam Hoskins <sam.hoskins@...>
To: Q-LIST <Q-LIST@...>
Sent: Thu, December 17, 2009 6:07:56 AM
Subject: Re: [Q-LIST] carbon

Jim, there is no all carbon Q.

I don't have any carbon in my main wing. The main wing uses standard UNI
glass, not BID. In preparation for the layups, I draw 45 degree lines on
the foam cores, to help ensure proper alignment of the two first layers, per
plans. Perhaps, that is what you are confusing,

The only change I made to the new wing was to add one proportionately sized
spar cap.

Sam


On Wed, Dec 16, 2009 at 10:23 PM, Jim Staud <staudjf@...> wrote:



If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to
stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing upgrade
in the Q-Talk 127 Photos. The revised main wing has noticeable carbon
strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed to
the cylindrical carbon spar. What were the results of that experiment and
waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce
landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.









------------------------------------

Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links


Sam Hoskins
 

The wing layups use UNI, per plans.

Sam



On Fri, Dec 18, 2009 at 10:24 PM, Jim Staud <staudjf@...> wrote:



Sam,

Is that the standard layup using only uni?

Are there any knowledgeable owners like yourself in the Dallas / Ft. Worth
area and venues to meet them?

Jim Staud

________________________________
From: Sam Hoskins <sam.hoskins@... <sam.hoskins%40gmail.com>>
To: Q-LIST <Q-LIST@... <Q-LIST%40yahoogroups.com>>
Sent: Thu, December 17, 2009 6:07:56 AM

Subject: Re: [Q-LIST] carbon

Jim, there is no all carbon Q.

I don't have any carbon in my main wing. The main wing uses standard UNI
glass, not BID. In preparation for the layups, I draw 45 degree lines on
the foam cores, to help ensure proper alignment of the two first layers,
per
plans. Perhaps, that is what you are confusing,

The only change I made to the new wing was to add one proportionately sized
spar cap.

Sam

On Wed, Dec 16, 2009 at 10:23 PM, Jim Staud <staudjf@...<staudjf%40yahoo.com>>
wrote:



If they did build an all carbon Q1, Q2, Q200, or TRI-Q, were they able to
stress test it, and what were the results?

I noticed what I think is Sam Hoskins aircraft getting a main wing
upgrade
in the Q-Talk 127 Photos. The revised main wing has noticeable carbon
strands in the BID.

Also read somewhere about someone using carbon rods as spars as opposed
to
the cylindrical carbon spar. What were the results of that experiment and
waht was the method of layup.

Did anyone ever add a carbon spar or spar caps to the main wing?

Did anyone ever grow the templates to build an upscaled wing to reduce
landing speeds and wing loading?

Did anyone ever put Q2 wings on a Q1?

Jim S.

[Non-text portions of this message have been removed]


[Non-text portions of this message have been removed]

------------------------------------


Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links






[Non-text portions of this message have been removed]


rick_nordgarden
 

--- In Q-LIST@..., "Robert X. Cringely" <bob@...> wrote:

An ALL-CARBON Q1 should carry its loads exactly like an ALL-GLASS Q1.
This is an example of how risky an untutored "common-sense" approach to engineering can be. Make two identical foam wing cores, then skin one with fiberglass and the other with carbon fiber. With the same number of layers of cloth of the same weight per square yard the carbon-fiber wing will be stiffer -- and therefore weaker. Uniformly stiffening a wing's skin alters its spanwise load distribution, shifting load away from the tips and toward the centerline; the wing's load-carrying capacity and its g-limit at a given load are both thereby reduced. Stiffness and strength are not necessarily complementary properties; to a great degree they're antagonistic. This problem can be overcome by altering the number and/or weight of the plies when switching materials, but that means re-engineering the structure -- the fuselage and bulkheads as well as the wing-skins and spar layups. Before you can build a *safe* all-CF Quickie you'll have to design one.

Rick Nordgarden
Council Bluffs IA
Dragonfly MkIIH under construction


Robert Cringely
 

What are the constraints on this design? On most composite designs the
deciding factor in how many layers to use on the wing skins, for
example, is hangar rash. Yes, hangar rash. Less glass could always be
used but it would be damaged too easily. So we sit around speculating
about the implications of changing materials on a design that's
overbuilt in glass OR carbon. What is the history of structural
failures on Quickies? Zero. Change it to carbon and it will still be
zero.

Bob


On Dec 19, 2009, at 1:50 PM, "rick_nordgarden" <grnordgarden@...>
wrote:



--- In Q-LIST@..., "Robert X. Cringely" <bob@...> wrote:

An ALL-CARBON Q1 should carry its loads exactly like an ALL-GLASS
Q1.
This is an example of how risky an untutored "common-sense" approach
to engineering can be. Make two identical foam wing cores, then skin
one with fiberglass and the other with carbon fiber. With the same
number of layers of cloth of the same weight per square yard the
carbon-fiber wing will be stiffer -- and therefore weaker. Uniformly
stiffening a wing's skin alters its spanwise load distribution,
shifting load away from the tips and toward the centerline; the
wing's load-carrying capacity and its g-limit at a given load are
both thereby reduced. Stiffness and strength are not necessarily
complementary properties; to a great degree they're antagonistic.
This problem can be overcome by altering the number and/or weight of
the plies when switching materials, but that means re-engineering
the structure -- the fuselage and bulkheads as well as the wing-
skins and spar layups. Before you can build a *safe* all-CF Quickie
you'll have to design one.

Rick Nordgarden
Council Bluffs IA
Dragonfly MkIIH under construction


[Non-text portions of this message have been removed]


Jeffrey Bevilacqua <jlbevila@...>
 

Rick,
Very well said and thanks for keeping us safe.
Jeff

--- On Sat, 12/19/09, rick_nordgarden <grnordgarden@...> wrote:


From: rick_nordgarden <grnordgarden@...>
Subject: [Q-LIST] Re: carbon
To: Q-LIST@...
Date: Saturday, December 19, 2009, 10:50 AM


 





--- In Q-LIST@yahoogroups. com, "Robert X. Cringely" <bob@...> wrote:

An ALL-CARBON Q1 should carry its loads exactly like an ALL-GLASS Q1.
This is an example of how risky an untutored "common-sense" approach to engineering can be. Make two identical foam wing cores, then skin one with fiberglass and the other with carbon fiber. With the same number of layers of cloth of the same weight per square yard the carbon-fiber wing will be stiffer -- and therefore weaker. Uniformly stiffening a wing's skin alters its spanwise load distribution, shifting load away from the tips and toward the centerline; the wing's load-carrying capacity and its g-limit at a given load are both thereby reduced. Stiffness and strength are not necessarily complementary properties; to a great degree they're antagonistic. This problem can be overcome by altering the number and/or weight of the plies when switching materials, but that means re-engineering the structure -- the fuselage and bulkheads as well as the wing-skins and spar layups. Before you can build a *safe* all-CF Quickie you'll have to design one.

Rick Nordgarden
Council Bluffs IA
Dragonfly MkIIH under construction











[Non-text portions of this message have been removed]