TommyWatson

My Feedback: (1)

I have a Hobbyking BAE hawk. It comes with very nice full ducting. The fan I purchased has an inlet lip. I have always thought that you should use the inlet lip on any fan.
Which would be best, to use the full ducting and do away with the inlet lip, or use the inlet lip and stop the ducting short of the fan. If I were to stop the ducting short of the inlet lip, how far short? See photos.

juanjulian

My Feedback: (9)

Since you have a full ducting work use the ducting instead of the lip.

Lip is usefull for a exposed edf configuration, where not able to put ducts and making test.

Your inlets in the jet and forward ducting is suposed to do the work of the lip.

Cheers

Juan

ACES&8s

Definately use the full duct!...I read about the lip on the intakes on a jet, where it's marked "danger jet intake" it has to be smoothly rounded, with not a sharp edge. The input edge of the fan needs to be sealed, as well as the output edge, to the thrust tube. Jepe jets (J.P. Shlosser) says it's even advantageous to smooth the inside of the duct, if its pebbly. I hope the inside of yuor ducting is smooth. My HET models have the fiberweave surface that's a little rough...not so good.

TommyWatson

My Feedback: (1)

Thanks Guys,
I have decided to use the full ducting. The inside of the inlet and exhaust ducts are very smooth in fact they are shiney. Also I will probably try to blend the edges of the fan shroud as Much as I can. When I was using BVM Glow fans, BVM was very much into smoothing the edges of the fan shroud so you get a smooth transition from the duct to the fan. Same on the exhaust side.

Thanks for all replys.

Regards