[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: More temperatures from N6Q



I had to move the deflector to within 1/16 inch of the static ports to get
the indicated air speed to agree with the speeds measured with my GPS.
movement of the defflector back to this position increased the indicated
airspeed by 10 knots.

----------
> From: Tim Crawford <crawford@atdd.noaa.gov>
> To: reflector@awpi.com
> Subject: More temperatures from N6Q
> Date: Tuesday, June 02, 1998 3:47 PM
> 
> Hi All!
> 
> Before todays third flight, I installed additional 
> thermocouples on the Franklin engine at the oil inlet 
> and outlet.  My primary monitor is a RMI micro-monitor 
> which uses an AD590 PN junction to measure oil temperature. 
> The RMI's sensor is installed in the nose-mounted oil 
> cooler exit line --i.e. I measure the return oil 
> temperature to the engine.  Simon and Duane had 
> expressed concern that this was not the correct 
> place to make the measurement.  
> 
> Today, I was also going raise the gear and open up 
> the speed envelope. Unfortunately, the Grear retract 
> sequence valve failed to close the nose gear doors.  
> So speeds are still slow but with most of the gear 
> parts up<g>
> 
> The observation for 110 and 130 kts 
> at 9,500 ft are as follows:
> 
>                       ---  oil temps----
> OAT  IAS   MP    RPM outlet Cooler inlet    Cyl's
>  C    Kts  "            C     C      C       C
> 12   108  17.7  2100   93    72     76    90-120
> 13   126  17.6  2520   97    77     79   100-140
> 
> I believe the 17C Delta temperature between the 
> engine in and out oil temperatures.  However, 
> the absolute thermocouple temperatures are not as
> reliable as the micro monitor's.  Obviously, the 
> oil cooler's oil exhaust temperature should be 
> between what is coming to and from the engine. 
> Regardless, I now trust the RMI's reported 
> temperature as reasonable.  Please note, so far
> this engine has not worked hard and these 
> temperatures will go up at high power settings.
> 
> While looking at various Velocity static ports, 
> I had noticed all had aerodynamic fences in 
> front of the static port to reduce sensed static
> pressure (or to make the aircraft go faster).  
> As a result, I moved my static ports down & back 
> to just in front of the door.  I expected this
> would be a lower static pressure region.  
> At 110 kt my airspeed reads 5 kts slow but 
> 1kt fast at 130 kts.  Also, today there was 
> a lot of wind, so my error estimates may be poor.  
> Regardless, I think I have found another
> complicated problem.  Any other experience 
> out there?
> 
> 
> ------------------------------------------------
>     _                        _
>      \                      /
>       >-}     Tim        {-<
>     _/                      \_
>  Long EZ N3R           Velocity N6Q
> 
> 
> 
> 
> 
>