Strut fairings anyone?

[Methusala]

Who out there has the best method of fairing the struts? There is a Thruster at Holbrook that uses a pvc moulding with cliplock joint at the trailing edge that looks simple and effective. Mystery as to where it may come from though. Hope this stirs some thoughts, Methusalah.

 

 

[Guest TOSGcentral]

Strut Fairings are the most useful mod for the Thrusters (any of them) as they give you an instant 5 – 6 kts extra cruise speed and a bit better glide.

 

They were produced by the factory as a retrofit option but of course the factory is no longer there.

 

There were three forms:

 

• The plastic sleeves that were held to the existing struts by hose clamps. I have never been able to find a source for these – but have not tried hard as I do not like them. They are very broad chord and could come loose easily. If they did then you would get serious roll trim problems.
   
   
  
• The existing struts were sleeved with alloy aerofoil section struts, but left entire. The material used was that employed on the Jabiru lift struts. They use capture rivets top and bottom to affix the sleeve to the strut, carry no load but do add to the weight.
   
   
  
• The same material is used but the existing struts are cut approx 18†from each end and the ends (including the 95.25 fittings) are used for attachement to the airframe via bolts and rivets, and the Jabiru strut now becomes load bearing.
   
  

 

NOTES.

 

• The metal strut material was commonly available (and quite cheap) but that is no longer the case. However it is around somewhere as they are still building Jabirus.
   
   
  
• There are no drawings available for #3 above (to my knowledge). TOSG may fix this later in the year as I intend to proceed with a certified modification to take the two seat Thrusters to 450kg MTOW and the aerofoil lift struts are part of this rather extensive procedure – so will have the engineering drawings for retrofits to existing aircraft that remain at the current 400 kg MTOW.
   
   
  
• When setting up the new fairings/struts – put the aircraft into a flying attitude and use water levels to align the struts with the cruise airflow before fixing them. This makes the struts look a little “odd†but is efficient. If you simply build the struts flat on the floor they look OK but the rear struts will be at the wrong airflow angle.
   
  

 

Tony