Protrusions Oh the protrusions

[INA201]

I have seen where a lot of us Mooney folks have smoothed their wings, hidden their antennae, added mods, etc.  I was just walking around the plane and looking at all of the protrusions into the airstream and thought of air hitting these. Looks like one is to add pressure to the battery box.  Another is a static drain maybe. Looks like a transponder antennae, mystery antennae?.  Anyone have good results or is it even smart and or feasible to clean all this up? I forgot to take a photo of the whisker antennas as well. Jet driven and others have gone the extra mile  smoothing wings as well. Just curious and thought it would make for some fun discussion.

[ArtVandelay]

You can unscrew the tie down rings and remove them. The marker beacon antenna can be move to the inside if you have fiberglass one piece belly. My temp probe is in the pilot side air scoop, probably best place for it, yours is in the worst place IMO.

[Hank]

So what is that giant piece of hex bar sticking up in front of the windshield? That's a crazy place to put a temp gauge, if that's what it is . . 

[INA201]

Pretty sure it's the temp gauge. Gonna stick it in the side air scoop when I get the JPI900 put in coming up. I'm not sure what the oblong fin antenna is In front of the ELT antenna.  I wonder if the ELT needs to stick out that much too. Seems like if it's activated it'll serve no purpose after it's scraped off on the trees and ground during an off airport landing.

[The Other Red Baron]

43 minutes ago, INA201 said:

Pretty sure it's the temp gauge. Gonna stick it in the side air scoop when I get the JPI900 put in coming up. I'm not sure what the oblong fin antenna is In front of the ELT antenna.  I wonder if the ELT needs to stick out that much too. Seems like if it's activated it'll serve no purpose after it's scraped off on the trees and ground during an off airport landing.

Glideslope?

Edited June 28, 2017 by revwatch

[ArtVandelay]

Pretty sure it's the temp gauge. Gonna stick it in the side air scoop when I get the JPI900 put in coming up. I'm not sure what the oblong fin antenna is In front of the ELT antenna.  I wonder if the ELT needs to stick out that much too. Seems like if it's activated it'll serve no purpose after it's scraped off on the trees and ground during an off airport landing.

That's the marker beacon antenna.

[Guest]

The blade antenna and the small stick antenna are DME and transponder.  They are interchangeable.  ELT is normally on the top of the tail section.

Clarence

[jetdriven]

Those small fin antennas, the Vor blades, and the marker beacon antenna have basically zero drag.  Rod antennas however have quite a bit. 

[Andy95W]

"Quite a bit" is pretty relative.

The blade antenna has a drag "weight" of .09 pounds at 250 knots; at 160 knots that's about .04 pounds, so yeah, basically zero drag.

The rod antenna as a drag of .41 pounds at 250 knots; at 160 knots that's about .168 pounds.

As a CB, I'm okay with that massive amount of extra drag. 

[jetdriven]

I was thinking more like ELT, cat whiskers, and rod shaped COM antennas. All of those add up to 3-4 lbs of drag which is significant.  But as you can see any round shape has about 8-10x the drag of an optimally streamlines shape. Instead of one Set of VOR blade antennas, imagine eight sets to offset those cat whiskers. 

[INA201]

where's a good place to move the ELT and possibly shorten the vent tubes? Would you guys consider the belly protrusions insignificant since they are underneath the plane?  How has the wing smoothing turned out?  Thanks 

[jetdriven]

The boundary layer in that area is pretty thick so those battery vents don't see the full 180-200 mph airstream. So drag cleanup doesn't pay as well. Later models have a flush vent that rivets to the inside of the skin, you can convert to that.

You can put the  ELT antenna under the dorsal fin. 

Wing smoothing is good. 

[amillet]

With a sealed battery, is the vent tube necessary?  Anyone removed it?

[Hank]

How much do you reckon this is costing me?

Replacing it looks very $heet metal inten$ive!

[jetdriven]

I took the cat whiskers off and put on blades. It's not easy as the fin is only about 7/8" thick there.  But it can be done.  The money would better spent elsewhere first, by optimizing the COM antennas, hiding the ELT under the dorsal if its fiberglass, adding either the J style horizontal root fairings or the LASAR ones, rigging check, gear doors real nice and tight, doors close flush, door seals, etc 

Edited June 28, 2017 by jetdriven