i3dm

My Feedback: (51)

Hello guys,

for those of you with Ultra Lightnings, do you recommend adding outlet holes in the bottom hatch?
Picture shows where i have mine so far - manual only discusses entry holes for cool air, no exit holes.
thanks.

Andrew Bird

I think the point is that the cooling air flows in and flows out between the inner and outer pipes of the thrust pipe - aiding cooling and also augmenting thrust. Cutting holes in the back would just stop the cold air from going where it was supposed to.

i3dm

My Feedback: (51)

actually the UL external pipe inlet is covered by the bypass, so i dont think air can flow in between inner and outer pipe.

scoeroo

My Feedback: (9)

In the ultra flash jet the air can be drawn between the inner & outer tubes
The ultra lightning it can not

Springbok Flyer

Yes, the UF and the UL are different - I have both. The UF is fitted with a 140 and the two narca cutout's, the UL is fitted with a 210 and no cutout's. Absolutely no heat issues with either of the two.

Cheers,

Jan

Andrew Bird

Sorry - my mistake! I thought it was the same as the UF

scoeroo

My Feedback: (9)

I feel it would have made more sense to allow air intake between inner & outer thrust tubes for performance reasons
I see the benefits in the UF and thought they would have done the same with the UL
The original classic lightning had you cut some naca ducts in the bottom but there was no place for air to move out
The manual for the UL I believe still has this mod in it, but then at the same time the manual has not been changed from one jet too the next