Re: Canard load test


David J. Gall
 

1G in bending (and 1G in shear) in an end-loaded condition does NOT equal 4.4G in bending (and 4.4G in shear) in a distributed load condition....

ASSuming a constant cross-section (depth) spar and a UNIFORM distributed load (no aerodynamic twist, taper, tip losses, etc.) then the end-loaded 1G condition will create an equivalent bending moment to a 2.667G UNIFORM distributed load (reference: any basic Statics text). Since the canard carries (arguably) 55% of the load, then the 2.667G figure could (arguably) be divided by 0.55 for a net 4.85G equivalent bending load, but that still neglects the shear load. However, these ASSumptions are nowhere near enough to the reality of the actual canard to qualify as "engineering calculations" nor will ANY calculations ever replace a proper load test on a newly-designed part like the one in question.


David J. Gall, BSAE

----- Original Message -----
From: "Mike Dwyer" <mdwyer@...>
To: Q-LIST@...
Subject: Re: [Q-LIST] Canard load test
Date: Thu, 30 Dec 2004 20:25:47 -0500



It has been calculated that the canard on a Q200 is sitting at 4G on the
ground when the plane is loaded to gross so a static test to 4 G is
pretty much meaningless.
I'll have to assume SkyDog doesn't fly as he doesn't post his name or
plane type...?
Mike Q-200


OneSkyDog@... wrote:


In a message dated 12/30/2004 11:25:41 AM Mountain Standard Time,
mdwyer@... writes:


Why don't you just put the plane together on the gear, load it to gross
weight and start it bouncing up and down. You'll be putting way more than
4G on the canard. Making a fixture adds tons of variables. This is
assuming you have a standard Q200. Your email doesn't say it you have a
nose dragger, Q or D-fly.... Mike Q-200






.....

Great,
I can not belive anyone would post this prescription to verify if a canard
is built right. The point of a load test is to proof the structure at a
reasonable operating load before the first flight not ultimate loads. You
can do this test during bad landings as you are really close to the ground
and you can't fall very far.

"Yep I load tested it it musta bounced a foot before the canard broke. I
have no idea of the dynamic load but it musta bin a lot."

Regards,

One Sky Dog







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