Re: CAD LS-1

David J. Gall


Don't bother! To quote Rutan: "Simplicate and add lightness. If you're
considering adding something to your airplane, throw it up in the air. If is
comes down, it's TOO HEAVY -- leave it out."

By the time you do all that structural stuff in order to support a
cantilevered axle, you could have cut off the old pants, sanded a five or
six degree bezel on the top, ground down all the old structural glass (to
save the weight) and reattached the pants at the new camber angle. No
re-engineering required. The stock pants have plenty of room for the stuff
that goes in 'em, or you could section the pants and widen them while you
have them off the plane. You mention the aerodynamic efficiency as a reason
for wanting to retain the GU canard, how about giving equal "weight" to the
structural efficiency (lightness!) inherent in the original pants?

I do not agree with the assertion that the GU canard is "more efficient" or
whatever your argument is for using it instead of the LS-1 canard. Stick
with tried and true and get it flying first. If you absolutely, positively
gotta do the re-engineering thing, either copy the built-up carbon spar that
Weishaar and Doyle built twenty years ago (for an LS-1, but usable for a
GU), or call Jim Marske and get a professionally engineered graphlite rod
spar and landing gear SYSTEM designed from scratch. That'll cost you about
$20,000 in development costs and consulting fees (or more!) but the
aerodynamics is already proven....

Hmmmm. Back to plan A: Fix the broken wheel pant, fix the alignment, do the
Jim-Bob six-pack, consult with your tech counselor and HEED his advice, get
a pro to test fly it, then go fly....

David J. Gall
PS Main wing winglets = drag, drag, drag! There is NO need to "increase the
efficiency" of the main wing. It does not EVER stall so reducing the stall
speed of the airplane means reducing the CANARD's stall speed.... Also, the
canard carries the brunt of the airplane's weight at cruise, so if winglets
were needed anywhere it would be on the canard! Of course, that would be
directionally destabilizing, so increasing the canard SPAN would be the
preferred method... But either canard winglets or increasing the canard span
will require increasing the main wing span so that the main wing remains
protected from EVER stalling... The circle of logic then puts you squarely
in the Waddelow increased-span camp, or taken to extremes gives you a
slow-ass Dragonfly instead of a Fassssst Q200.... It's ALL been discussed
here before, see the archives I'm too tired to re-hash it all again. The
Q200 continues to be one of the aerodynamically BEST airplanes EVER! Don't
think you can improve it without a Jon Roncz AND a Jon Sharp on your team!
Again, JMHO!

-----Original Message-----
From: larry severson [mailto:larry2@...]
Sent: Thursday, October 21, 2004 3:40 PM
To: Q-LIST@...
Subject: Re: [Q-LIST] CAD LS-1

Anyone who disagrees, feel free to flame me on my personal
e-mail address.
For considered comment use the net.

A thought for those who are about to start cutting foam for
the canard on a
Q2 ( based on the published results of the VGs on a GU canard
by JimP).

If you create the GU canard, then:
1. Cut off both tips (width of pants) (for gear inside, or
not for gear
2. Cut out the center (3" wide) of the canard foam full span
and round edges for the next step 3. Carbon fiber glass the
cut out foam 4. reattach foam to new carbon fiber spar and
fill the remaining grooves with flox 5. create a 3" wide X 1"
deep carbon fiber gear leg at the end of spars 6. cut the end
tips to fit the gear legs (unnecessary for outside geat) 7.
finish the wings per the plans 8. create the pants per the
plans, except for the cutout for the gear legs.

9. Add the VGs per Jim P's #3 format tests when ready

Would add 3 hours to the construction time and $150 (carbon
fiber and VGs) to cost, but increase GW to/above the LS1
while maintaining efficiency.
Adding winglets to the wing would help reduce stall speed
further while increasing cruise speed by effectively
increasing wing span and reducing drag.

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

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