Turbulence Between The Stakes!

All,

The instructions for most altimeters require that the altimeters be located in a rocket such that they will experience little or no turbulence from the pressure ports on the rocket while in flight. I am faced with just such a dilema...my altimeter pressure ports are designed between the smallest portions of the 4 strakes on the airframe. There will be a total of 4 ports.

Based on anyones experience, could this be an issue? This late in the build, I have very little room, if any, for a change.

Note: This airframe set-up is for an L3 flight.

Johnnie

View attachment Pressure port locations.pdf

I think you will be fine. Normally the concern is that the turbulence is in front of the pressure ports (like having pressure ports just aft of a reducer).

Crazyrocket said:

I think you will be fine. Normally the concern is that the turbulence is in front of the pressure ports (like having pressure ports just aft of a reducer).

Click to expand...

I agree. The fins should keep the air moving striaght anyway. Plus the strakes aren't that large.

Ben

Crazyrocket said:

I think you will be fine. Normally the concern is that the turbulence is in front of the pressure ports (like having pressure ports just aft of a reducer).

Click to expand...

I figured the airflow being caught between the strakes would be worse...I did fail to mention, that the leading edge of the strakes is a square edge, and there is currenly no plan to round or sharpen the leading edge.

Johnnie

What altimeter are you planning on using?
An altimeter with dual sensors, barometric and accelerometer can sometimes not be adversely effected by potential turbulance. Two examples are Mission Control and ALTACC.

The Mission Control can be programmed to use the ACC only or a combination of ACC and Baro for sensing apogee.

ALTACC uses the ACC to determine Apogee and the Baro for Main deployment. Both of these altimeters also eliminate problems of false readings during Mach+ flights without using a timer inhibit for Mach.

The altimeter pressure ports are still needed, however you may not have much of a problem compared to a Baro only altimeter. Check your user manual and consult with the manufacture if there are any doubts.

John