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Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 9:45 am
by dbdevkc
I am still building, but I see in my factory supplied flight manual in the Operating Checklists/Walk Around Inspection, #2 (which is the tail section): "c. Inspect/Install pitot/static tube (Waiex)."

Was this always an option on the Waiex? The only one flying like that that I am aware of is Kip Lorie's Waiex, I also know that Bryan's build has that also. But I was pretty sure that it was a custom build option.

Re: Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 12:03 pm
by Bryan Cotton
I have no idea if it was ever an official option. One less thing to connect at the wing root is a bonus though. And if my tube is ever destroyed, it is easy to pull it out and put another in.

Re: Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 12:55 pm
by Bryan Cotton
In this old Xenos article it looks like the factory ship has a tail mounted pitot or total energy probe.
https://www.sonexaircraft.com/kitplanes ... l-wonders/

Re: Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 1:20 pm
by scotttro
You know, that brings up an interesting question: If a pitot/static works in the tail, might an LRI probe?

Re: Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 2:06 pm
by Bryan Cotton
I'd say no. Doesn't an LRI measure delta- pressure between the top and bottom wing surfaces?

Re: Pitot in tail of Waiex

PostPosted: Sat Nov 30, 2019 6:51 pm
by GordonTurner
I would say it would. The probe isn’t sampling pressure above and below the wing, but the change in relative pressure between a pitot at (roughly) zero degrees incidence and one at minus 45 degrees incidence. The two probes could be anywhere.

Gordon

Re: Pitot in tail of Waiex

PostPosted: Mon Dec 02, 2019 1:25 pm
by Onex107
An AOA or LRI should be mounted 90 degrees to the wing, where ever it is mounted. It is actually measuring the angle of attach by using differential pressure above and below. I presume you are talking about mounting the sensor on the "Y" tail, at an angle. Mounted vertical to the wing it might work, if the wing doesn't blanket the tail at a stall angle of attack. It's an excellent instrument to add. It will improve your landings. The plans are on the internet.

Re: Pitot in tail of Waiex

PostPosted: Mon Dec 02, 2019 2:06 pm
by racaldwell
I built a diff. pressure LRI for my RV6. ( I mounted the tubes in a hollow windsurfing fin mounted to the bottom of the wing.) It works well. However, you have to look at it for it to have any value. I just can not look at it while very close to the ground and slow airspeed because all my attitude queues are outside the window. I have the guage mounted high on the panel just to my right but just don't feel comfortable taking my eyes off the runway area. In hindsight, that project was a waste of time for me.

I do have a TE probe with pitot and static mounted to the tail of my Xenos. The LRI probes would work there just fine.

Rick Caldwell
Xenos 0057

Re: Pitot in tail of Waiex

PostPosted: Mon Dec 02, 2019 4:17 pm
by Rynoth
Rick, that's a good point on the location of the instrument, as it's only useful if you can see it in the phases of flight where it's useful. On top of the dash can be a good place to put it if it doesn't otherwise obstruct your view (varies for different aircraft of course), but I've found mine to be very easy to reference in my Waiex by mounting it directly in front of me near the top of the instrument panel, essentially as a primary instrument, right next to slip/skid indicator which is equally important in slow flight.

Image

Re: Pitot in tail of Waiex

PostPosted: Tue Dec 03, 2019 1:28 pm
by Onex107
Mine was a late addition so it's not in the panel. It's about like Ryan's but on top of the panel down next to the windshield as far as it will go. Not pretty but easy to watch as you land. Built from 1/4 inch alum scrap and plumbed to a $60 differential gage. Mounted on the inspection cover under the left wing. Adjusted to stall at the red.