Wright Flyer.

[Jerry Budd]

The 1903 Flyer was flown with ~ minus 23% static margin (the center 
of gravity is located 23% of the mean aerodynamic chord behind the 
neutral point).  That's very pitch unstable.  Fortunately the dynamic 
pressure is low (a function of velocity squared) so the time to 
double amplitude is not so short making it flyable (barely).  The 
lack of pitch control authority and low pitch damping along with some 
hysteresis and a low wing/power loading didn't help either.

About 15 years ago I was able to fly the CalSpan Variability 
Stability LearJet for about 90 minutes as part of an accelerated 
placement program at work.  The flight demonstration illustrated how 
different aircraft instability levels, time delays, and stick gearing 
functions can adversely impact precise tracking trasks and pilot 
handling quality ratings.

We (the guy in the left seat was an Israeli F-4 ace) flew several 
aircraft and stick combinations (conventional center stick, stickside 
with stick force, sidestick with force/displacement combination, and 
with stick centering turned off.  The two aircraft I remember the 
most are the X-29 (with SAS off) and the Wright Flyer.  Even though 
the X-29 was more unstable in pitch than the Wright Flyer, it was 
much easier to fly (probably due to the much greater pitch control 
authority of the X-29A ).  Conducting precise tracking tasks were out 
of the question, however it was surprising how easy it was to keep 
the "pointy end" forward for more than a few seconds.

Oh, and it was educational and fun too!   : )

Jerry


>Hmmm CG.
>
>In the replica documentary I saw CG issues in the test flights but 
>heard no documentary to that effect. When it went violently up and 
>down fast with the female, ergo lighter, pilot, they should have 
>seen the weight distribution clue. We all know that pitch 
>sensitivity is almost always a tail heavy plane....
>
>Maybe Mr. Wright was a wee bit heavier...
>
>E.
>
>
>-----Original Message-----
>From: discussion-request at nsrca.org 
>[mailto:discussion-request at nsrca.org]On Behalf Of Troy Newman
>Sent: Thursday, December 18, 2003 8:04 PM
>To: discussion at nsrca.org
>Subject: Re: Wright Flyer.
>
>Watch the History channels stuff on it...The Utah State guys 
>improved the original...and they found a major CG problem with the 
>pilot laying down the wing....So they moved him ahead of the 
>wing...Solved the pitchy problems....They also made major changes to 
>the plane like air foils and materials...and a Harley engine with 
>65hp.
>
>They flew it a bunch and were making normal flights with 
>it...including turns and so on. Actually flying around and buzzing 
>the field. I think I they said over 200 flights on the plane....It 
>had some failures early on but seems to be a cool replica. The Grad 
>student in charge wanted to improve upon the Wrights work and make a 
>better plane....
>
>The idea was to not do what had already been done...It was build on 
>the work already done. That is what Wilbur and Orvil did...The 
>trashed the 1903 plane after the 4th flight and the wind damage and 
>went home to build the a better version with what they learned in 
>about 90 secs of flying the 1903 plane.
>
>Cool stuff.
>
>I'm a Aero freak and I love this stuff. I have watched the shows 3-4 
>times and will continue. These might be ones I actually spend the 
>$30 on and purchase from the History channel.
>
>
>
>TN
>
>From: <mailto:Eric.Henderson at gartner.com>Henderson,Eric
>
>To: <mailto:discussion at nsrca.org>discussion at nsrca.org
>Sent: Thursday, December 18, 2003 7:48 PM
>Subject: RE: Wright Flyer.
>
>I don't seem to be provoking the responses that I was looking for. 
>(I have no issue with the achievement or the replication).
>
>What I am really interested in the ways to get the plane to fly 
>better and if anyone saw it as a CG issue? I thought that the 
>collective knowledge pool in this list might have some ideas on 
>fixing the flyability issue.
>
>Regards,
>
>Eric.
>
>
>-----Original Message-----
>From: discussion-request at nsrca.org 
>[mailto:discussion-request at nsrca.org]On Behalf Of Rcmaster199 at aol.com
>Sent: Thursday, December 18, 2003 7:40 PM
>To: discussion at nsrca.org
>Subject: Re: Wright Flyer.
>
>In a message dated 12/18/2003 10:00:06 AM Eastern Standard Time, 
>Eric.Henderson at gartner.com writes:
>
>>Subj:Wright Flyer.
>>Date:12/18/2003 10:00:06 AM Eastern Standard Time
>>From:<mailto:Eric.Henderson at gartner.com>Eric.Henderson at gartner.com
>>Reply-to:<mailto:discussion at nsrca.org>discussion at nsrca.org
>>To:<mailto:discussion at nsrca.org>discussion at nsrca.org
>>Sent from the Internet
>>
>>
>>
>>I have been avidly following the progress of the Wright Flyer 
>>replica. It's driving me nuts watching them try to fly it. (Is 
>>there an aeronautical engineer on the project? - looks a lot like 
>>pilots and carpenters)
>>
>>
>>From where I sit, admittedly in my arm chair, the thing looks, acts 
>>and flies very TAIL HEAVY!
>>
>>The engines are behind the CG on the wings. There's almost nothing 
>>up front to bring the CG to a decent stable point. Am I off base 
>>here?
>>
>>Also I have meddled with models of the plane a little. Wing warping 
>>that goes only goes down induces worse wash-in at the slowest of 
>>speeds and is pretty nasty in the model. Instead of lifting the 
>>wing it drags it back making the plane turn adversely to the 
>>intended input. I know that they were trying to fly an exact 
>>replica so they went with everything as true to history as 
>>possible, but it is frustrating watching it struggle.
>>
>>Any thoughts,
>>
>>Regards,
>>
>Eric.
>

-- 
___________
Jerry Budd
mailto:jbudd at qnet.com
=====================================
# To be removed from this list, send a message to 
# discussion-request at nsrca.org
# and put leave discussion on the first line of the body.
#