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Re: Europa-List: Aerodynamicist question - Bud Yerly

Subject: Re: Europa-List: Aerodynamicist question - Bud Yerly
From: Pete <peterz@zutrasoft.com>
Date: Mon, 18 Jan 2021 09:29:49
Bud,
Do you know where the mono stacks up in these params?
Cheers and thx,
Pete

> On Jan 18, 2021, at 9:27 AM, Bud Yerly <budyerly@msn.com> wrote:
> 
> =EF=BB
> =46rom history Paul.
>  
> Raise the popular tail wheel aircraft and note the position in level attit
ude of the main axle to the leading edge of the mean aerodynamic chord.
> If you drop a plumb bob from the leading edge of a say a 7AC Champ or Cita
bria (rectangular wing so the mac is the leading edge)  the string goes thro
ugh the axle.
>  
> There are many aerodynamic effects as well as geometry effects to position
ing landing gear for a delightful conventional setup.
> As you push the stick forward, the main wing begins to go negative prevent
ing nose over as the tail cannot overpower the wings negative lift.
> The gear length allows a very near stall attitude at touchdown.
> The elevator position is such that it is above the wing downwash at touchd
own for stalled landings.
> Rudder area is such that the rudder can control the aircraft below stall s
peed.
> Fuselage area vs tail area and sideslip capability for crosswinds.
>  
> Geometry is important also.  Much has been written:
> The angle of the gear to the CG to the vertical CG axis longitudinally.
> The angle of the gear to the CG laterally for stability.
> Tail volume and length in relation to the gear. (AKA short coupled)
> Tail wheel to main gear distance in relation to gear width.
> Main gear movement in relation to touchdown forces (splay, compression, sp
ringiness etc.).
>  
> All these things determine whether a conventional gear aircraft is delight
ful or a handful to land.
>  
> Best Regards,
> Bud Yerly
>  
> From: owner-europa-list-server@matronics.com <owner-europa-list-server@mat
ronics.com> On Behalf Of Paul McAllister
> Sent: Sunday, January 17, 2021 10:16 PM
> To: europa-list@matronics.com
> Subject: Europa-List: Aerodynamicist question - Bud Yerly
>  
> Hi Bud (and anyone else who is knowledgeable on the topic)
>  
> I was once told l that there is an ideal front wheel position for tail drg
gers, something like 100mm in front of the MAC and that wheel placement of t
he mono was not ideal.  I can't remember where I heard this or if it was fro
m a knowledgeable source.
>  
> Would you happen to know if there is any validity in this?
>  
> Thanks and regards, Paul


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