Re: Header tank pressure line
The G280 NACA on the lower outboard wing surfaces add about 4lbs of pressure to the wing tanks at max cruise (which is much greater speed than any Q will see). G280 NACA is about 1 inch deep from the lower wing skin surface. They are also the wing vents when fuel is pumped in. I will be adding this feature to my fuel system.
The wings were tested at that amount (except once when the gauges were changed out and the tech didn't realize until too late that he went well over 4,, more like 40lbs!.. Wing became instantly bloated like a week long drowned cow and went BOOM!... Disposition: Scrap; repair not economically feasible, Ouch..there went a few million down the drain).
Jay is 100% correct. The bugs making nests become a concern..at least in these parts they are. Mud daubers.
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jay Scheevel <jay@...>
Sent: Sunday, March 21, 2021 5:31 PM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Header tank pressure line
I think I remember seeing this proposed in the past, but I have not seen it in any of the planes I have seen flying. One thing to consider: The reason a NACA duct works is because it causes the flow near the skin to de-pressurize slightly, so it changes direction and into the duct. On the other hand, you want maximum ram air pressure to the tank, so you need to extend the ram tube far enough away from the surface of the fuselage to get full velocity airflow. This is why the header ram air tube and also the pitot tube have stand-offs from the fuselage and/or wing surface. Suggest you keep that design. It is not much drag and it has valuable benefit to fuel flow.
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Nick Wright
I saw (forget what website) the header tank pressure line was ran through the NACA opening on the side of a Q200. Does anyone have any we experience with this? Is the airflow adequate in this location?
On Sun, Mar 21, 2021, 5:35 PM Mike Dwyer <q200pilot@...> wrote: