Hello, I have an issue with my Red Arrows Bae Hawk. When I sit the turbax fan in the jet for mounting, I noticed that the intake duct does not fit tightly around the front of the fan.
When the fan is centered in the duct there is approx. a 1/4 '' gap (maybe a little less) all the way around the fan shroud. Does anyone have a fix for this problem?
Should I build a balsa ring a 1/4 '' thick and glue it inside the intake duct so there will be no gap between the shroud and intake duct?
Has anyone seen this problem before?
Thanks for your help.
David

Hi david,

I'm sorry - I don't know the particular airframe you mention but...

In order to get the best performance, you do need to close that gap in the intake. My advice is to NOT simply glue a ply/balsa ring in the intake as it will make a step causing turbulence. I think the smoother the airflow in the intake all the way to the fan, the better the performance.

What I would do is take some poly-ply / FG sheet / Mylar and make a cone that will glue flush inside the intake and gradually come down to the diameter of the Turbax fan. In other words, like a funnel.

Hope this helps.

Adil

Thanks Adil, I will try something of that nature.

I ahve the opposite problem, mine is too small for a Ramtec fan.

Depending on how small the size difference, your problem is actually easier to fix, Just cut some slots in the intake, slide the fan in, spot glue some FG cloth on top of the slits / cuts and let dry. All Done

Now, if you tell me that your inlet is only 3", you DO have a problem

Adil

It's actually 5" even. Whish I ahd a Dynamax laying around. That extra 1/8" on the Ramtec makes it a real pain in the ***** to
install.