pitot probe

[Guest fly]

Hi all, greetings

 

In Tosg bulletin n#39 page5 "the alloy extension tube fits over the copper pitot head"

 

AS I have neither the copper pitot head or extension tube, but only a hole in the pod front "

 

What does an copper pitot head look like ?

 

can I just screw a suitable fitting through the hole in pod[ grommet mounted] to take extension tube at one end and plastic tubing the other

 

Can I just run a plastic tube from a aluminium extension tube and "T" or "Y" as necessary off to my static head ,ALT,ASIand VSI.

 

is 8"to 10" extended enough for clean air {no smart comments]

 

Thanks all inputs appreciated................................FLY

 

 

[Guest TOSGcentral]

OK Fly,

 

Your several questions:

 

• The extension tube is 6†long. It is made from the same material dimensions as used in your wing battens (for example). It does not need to be T6061 as it is non structural. However it does need to rigid so as to withstand yawing forces.
   
   
  
• The pitot head itself is probably some kind of common plumbing fitting – I do not know the origin. It has a mushroom head approx 1†diameter that is external to the pod. To this is brazed an extension pipe protruding forward about 1.5†to which the extension tube is fitted by a rubber grommet (or a suitable piece of poly tubing) for a firm and sealed fit. The barrel of the head goes through the pod and the back half is threaded to allow a nut that captures the head to the pod. There is then an extension tube at the back that allows the fitting of standard poly tube instrument tubing.
   
   
  
• The Thruster is simple enough not to require a total energy pitot/static system so it is quite OK to just connect the pitot head to the ASI (The pitot connection is normally the central outlet at the back of the instrument and will be labelled P. The other outlet will be labelled S (for static).
   
   
  
• You do NOT interconnect the pitot and static systems!!!! The static system is from a head mounted on the starboard side of the pod slightly ahead of the cockpit crew entry. This is a copper tube that extends perpendicular to the pod for about 5†and then is curved forward and extends a further 6â€Â. It is affixed to the pod in the same manner as the pitot head.
   
   
  
• If you have not got the pitot head then it is unlikely that you have the static head. The latter is of not much account in Thruster style operations and you can safely use “cockpit staticâ€Â. This means simply not connecting anything to the ASI static outlet but ensure that you leave it open and do not seal it.
   
   
  
• Working on the pitot head is a bit of a nuisance (the latest “Swift†pods have a forward inspection hatch to alleviate this. You wind up flat on your back, buried under the instrument panel, very uncomfortable and usually with a leg hanging out of each side of the pod! Therefore this is a good exercise to get your partner to do and you can give her a good pre-flight inspection during the proceedings – because she is not going to go anywhere very quickly!
   
  

 

Tony