REFLECTOR: Speeds

[Kevin Baker]

Hi Richard,
I concur - I think that is very well for a Std RG.
I have a LWFG and see 155 ktas so yours sounds about right.
I also have seen other Std RG Velos for sale that claim 165ktas at 10k.

That's what 195mph... sounds great to me... :-)   I'd take it.

Thanks,
Kevin Baker


On 6/6/2012 6:48 PM, Scott Derrick wrote:
> Richard,
>
> I think your doing very well at 170 KTAS..
>
> I haven't seen a Std RG any faster when comparing TAS.
>
> I don't have much confidence when I hear somebody reporting faster 
> speeds than that with an STD RG. The longwing STD's are 5-10 knots 
> slower than the orig STD.
>
> There are two main reasons for incorrect airspeed reporting in 
> homebuilts.
>
> 1.) the pitot Static system has not been calibrated. Usually this is a 
> result of a bad static reading. The only way I know of to check this 
> is a very low(50 ft) pass over the runway at cruise speed. before the 
> pass set your altimeter(on the ground) and verify the altitude on your 
> altimeter, add 50 ft for comparison. During the low pass write down 
> the altitude.  If it is off by more than then 50 ft, you probably 
> should adjust your static port. If it reads higher than it should you 
> have too much static pressure, if lower you have too little. I 
> adjusted mine with a small piece of aluminum tape in front of my port, 
> this reduced the pressure and now I read the correct altitude. Because 
> the IAS instrument is a comparator, comparing the pitot pressure 
> against the static pressure, if your static port is off your airspeed 
> indicator will be too.
>
> 2.) The other reason is the confusion between GPS ground speed and 
> TAS. Yes if you are in a no wind situation, very very rare, they are 
> basically equal. but more often than not they are not and you will 
> need to subtract a tailwind component or add a headwind component.
>
> Scott
>
> -------- Original Message --------
> Subject: Re: REFLECTOR: Speeds
> From: Richard J. Gentil <richard at naples-air-center.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Date: 06/06/2012 04:02 PM
>
>> Hi Scott,
>>
>> I am talking true airspeed. I am taking the alt, barometer, and OAT 
>> and using the KIAS I calculated my KTAS. I flew a triangular course 
>> and compared the GPS Ground speed to what the E6B was showing.
>>
>> I pushed the mixture, prop, and throttle full foward and let the 
>> speed stabilize on the two EFIS screens and wrote down my numbers. I 
>> tested several altitudes from on the deck up to 6,500 feet.
>>
>> Richard
>>
>> Sent from my iPhone 4 Classic
>>
>> On Jun 6, 2012, at 5:12 PM, Scott Derrick<scott at tnstaafl.net>  wrote:
>>
>>> Talking speeds kind be very frustrating.
>>>
>>> The only speed I like to talk about is KTAS,  Thats Knots True Air 
>>> Speed
>>>
>>> not statute miles nautical miles, not indicated airspeed true 
>>> airspeed, and certainly not ground speed(GPS).
>>>
>>> My IAS indicator has a TAS window, you select what your pressure 
>>> altitude in reference to the OAT(upper window) and YOUR TAS will be 
>>> indicated in the lower left window.
>>>
>>>
>>> <jfaeejhi.jpeg>
>>>
>>> You can also fly a triangular course, using the GPS ground speed ,  
>>> and compute a fairly accurate TAS from that.
>>>
>>> And of course some of the higher end glass cockpits can compute it 
>>> for you.
>>>
>>> And if flying very near to sea level on a std day temperature wise 
>>> and assuming your IAS indicator is close to cal, it will show TAS.
>>>
>>> So Richard when you say 170 kts, what kind of speed are you talking 
>>> about and how are you measuring it?'
>>>
>>> Scott
>>> -- 
>>> Talk sense to a fool and he calls you foolish.
>>> Euripides
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>