Pitot tube location.

[James]

Update:

I fix aircraft for my day job, so I'm always keen to break the rules and make up my own steps when I come home to work on the bearhawk :-)

For those of you who fit a AN5812-type Dynon pitot probe, they talk about tapping and drilling a #6 screw to hold the probe into the mount.
I thought this sounded like lots of work, so I mixed up some 2-pack adhesive (I used 3M brand 2216), and glued it in.

Then I through-drilled two 3/32 holes either side of the pitot tubes, and put in a couple of spring/roll pins.
Measure the width of the probe over the holes, and grind down the roll pin to sit just under-flush.
I sealed the hole with more adhesive.

I'd be surprised if the probe ever fell out, at the grandpa speeds I intend to fly! :-)

James

[Nev]

Has anyone had any experience with a boom pitot ? I’ve ordered one (in error) and wondering whether to proceed with installing it.

EEC06CC8-CFCF-4231-B74C-50FAA2EDBDB6.jpeg

[Battson]

Good for hunting geese with, if nothing else

[AZBearhawk272]

That is exactly what I have. Installs nice, have not flown it yet.
Most of my time in Bearhawk’s has been in boom pitot planes and they seem to me accurate if you get the opening at least 14 in from the wing LE.

Kevin D
# 272

[Nev]

Kev, how did you install it ? I couldn’t find any install kit such as the L version has. Anything I need to know ?
Thanks.

[James]

Yeah Nev - there's little to no info from dynon for their version of the boom probe. It doesn't come with the heater option either.

I had a generic boom type probe already installed in my wing when I bought the kit second hand. From memory, it's a Raven type, combined pitot / static in the one probe. It comes with a green support mount, a small box about 2"x2" by 3/4", which bolted onto the front spar. I just left it as I found it.

It's pretty confronting to see that hole drilled through your leading edge. Some of the guys on this forum question the accuracy of combined P/S probes, and prefer the separate static ports down the side of the fuselage. My big thing was safety around the stall speeds, and your kiwi partner in crime Battson convinced me the Dynon L-type probe with audible AOA sensor would be a big safety feature. So I put a second Dynon L-type probe on the other wing, and used the first boom PS probe to run an old-school ASI. That's my instrument redundancy :-)

Hope this autobiography helps you decide whether to fit it / change it

James

[alaskabearhawk]

I think Russ Erb did on his aircraft.

[BravoGolf]

Wings 128.jpgWings 133.jpg

I fabricated an additional mount for an AeroSteen pitot tube. This Pitot tube has a base for mounting to the spar as Bob suggests in the Bearhawk book. I added a side mount that uses the nose rib for additional support. Even with a doubler on the spar web I felt the tube had a little too much flex. I also have the Dynon boom pitot tube and I could have fabricated a mount for it but decided on the other pitot tube.

[Nev]

Thanks guys.

James - I agree with Battson regarding the value of an audible AOA signal rather than a visual one, definitely good to have. My understanding is that the boom type is compatible with this so it should really be a matter of deciding how to mount it. I did find another forum where a Dynon rep had suggested that most people use “hose clamps” which I take to mean Adel clamps on a rib. Appreciate anyone correcting me on any of this if I’m wrong.

Yep I would think the static ports on the rear fuselage should be a safe bet.

[Nev]

...,they seem to me accurate if you get the opening at least 14 in from the wing LE.

The Dynon boom is only 12 inches in length so this won’t be possible. I guess one way would be to fabricate a slightly larger diameter sleeve that is mounted to a rib, and slide the boom into it.

[AZBearhawk272]

That is exactly what I did. Heavy walled 6061 al tube with a notch cut in the side to allow the lines to exit down the wing.

Kevin D
#272