REFLECTOR: V-SPEEDS

Jim Sower canarder at frontiernet.net
Sun Jul 18 20:55:09 CDT 2004


<...  maximum structural cruising speed ...>
Are you talking about Vmax or "Maneuvering speed"? Vmax can be pretty 
arbitrary - the speed at which the designer assures us we won't come to 
pieces from flutter or something. Maneuvering speed would be at around 
140 kts. Maneuvering speed (known in some circles as T-Storm penetration 
speed) is IIRC the highest speed at which you can't over stress the 
airplane. Basically, it's the stall speed multiplied by the square root 
of the G rating of the airplane. For a Velocity rated at 4 Gs, it's 
twice stall speed, or about 130-140 kts. At or below that speed, you 
can't bend the airplane. You stall before you exceed rated Gs.
As best I recall from aerodynamics 101 ... Jim S.


jack davis wrote:

> Hi Ronnie,
> Actually, if you talk to the factory they will tell you that the Va 
> speed was arbitrarily chosen and has nothing to do with structural 
> issues of the control surfaces. Although I would agree with you that 
> it is somewhat smoother at 140 knots than 170 knots when in 
> turbulence, it really isn't bad at all in a Velocity. I've done it 
> many times while flying IFR. My green arc goes from 65 to 180.
> Happy flying . . .
> Jack
>
>     ----- Original Message -----
>     *From:* Ronnie Brown <mailto:romott at adelphia.net>
>     *To:* Velocity Aircraft Owners and Builders list
>     <mailto:reflector at tvbf.org>
>     *Sent:* Saturday, July 17, 2004 4:34 PM
>     *Subject:* Re: REFLECTOR: V-SPEEDS
>
>     Jack, the green arc is from the minimum clean speed to the maximum
>     structural cruising speed. The 170 knots would get pretty bone
>     jarring in heavy turbulence. The maximum structural cruising speed
>     is the maximum airspeed in smooth air. Also, the plane should be
>     able to withstand vertical gusts above 30 kts without sustaining
>     airframe damage.
>     So I think my markings are correct. Of course I didn't do any
>     testing to verify this!
>     Ronnie
>
>         ----- Original Message -----
>         *From:* jack davis <mailto:n767sd at hotmail.com>
>         *To:* Velocity Aircraft Owners and Builders list
>         <mailto:reflector at tvbf.org>
>         *Sent:* Saturday, July 17, 2004 2:22 PM
>         *Subject:* Re: REFLECTOR: V-SPEEDS
>
>         Only one comment on Ronnie's V speeds. I believe the factory
>         indicated that they shipped airspeed indicators in the past
>         with incorrect labeling. The Green Arc should go from 65 to
>         170 Knots. At least on the Standard wing you will typically be
>         indicating 160 knots at 75% power.
>         Jack
>
>             ----- Original Message -----
>             *From:* Tom Martino <mailto:tmartino at troubleshooter.com>
>             *To:* Velocity Aircraft Owners and Builders list
>             <mailto:reflector at tvbf.org>
>             *Sent:* Friday, July 16, 2004 4:45 PM
>             *Subject:* RE: REFLECTOR: V-SPEEDS
>
>             Thanks Ronnie! Were these derived from your flying
>             experience? Or do you have a flight manual from somewhere?
>
>             -----Original Message-----
>             *From:* Ronnie Brown [mailto:romott at adelphia.net]
>             *Sent:* Friday, July 16, 2004 2:14 PM
>             *To:* Velocity Aircraft Owners and Builders list
>             *Subject:* Re: REFLECTOR: V-SPEEDS
>
>             For my 173 Elite RG:
>
>
>               *Airspeed Limitations*
>
>             VNE – Never Exceed Speed 200 knots
>
>             VNO – Maximum Structural Cruising Speed 140 knots
>
>             VLE – Maximum Landing Gear Extension Speed 120 kts
>
>             VFE – Maximum Speed Brake Extended Speed 110 kts
>
>
>               *Airspeed Indicator Markings*
>
>             White Arc – Speed brake operating range 65-110 kts
>
>             Green Arc – Normal Operating Range 65-140 kts
>
>             Yellow Arc – Operations must be conducted with caution and
>             only in smooth air 140-200 kts
>
>             Red Line – Maximum speed for all operations 200 knots
>
>                 ----- Original Message -----
>
>                 *From:* Tom Martino <mailto:tmartino at troubleshooter.com>
>
>                 *To:* reflector at www.tvbf.org
>                 <mailto:reflector at www.tvbf.org>
>
>                 *Sent:* Friday, July 16, 2004 3:33 PM
>
>                 *Subject:* REFLECTOR: V-SPEEDS
>
>                 I have to calibrate my airspeed indicator (on an EFIS
>                 system) ... is there an official flight manual for the
>                 Velocity with such speeds for various models? I
>                 realize each plane will be slightly different ... but
>                 I simply want a starting point. Where can I find those
>                 numbers?
>
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