Parasite drag

[Cruiser]

I was flying today. Level flight in smooth air when I entered very light rain. Almost a mist actually. As I watched the water stream back from the windshield I looked at the ASI and found that I had lost 3kts! 

When I cleared the rain cell and the plane dried off quickly my 3kts. came back.

 

First time I had every noticed this, probably because the ride was so smooth.

[airkraft]

Interesting.  Parasite drag or engine producing a bit less HP or both?

Last time I had totally smooth air on a long X/C, I noticed that my seat position could actually affect the trim.

 

[GeorgePerry]

I routinely slide my seat back a couple of clicks after getting safely airborne for just that reason.  I also put any items that I don't need during flight in the baggage area. 

[N57039]

Water on the wings absolutely will slow you down. Laminar flow wings are very sensitive to this. Heck, the dead bugs on your leading edge will decrease performance.

[The-sky-captain]

Interesting article Jim, thanks for the heads up. The article mentions using "Vision" made by Turtle Wax. Is anybody familiar with this product? Any other good wax recommendations?

[Parker_Woodruff]

Quote: The-sky-captain

Interesting article Jim, thanks for the heads up. The article mentions using "Vision" made by Turtle Wax. Is anybody familiar with this product? Any other good wax recommendations?

[mooniac227]

I've used Rejex for YEARS.  Guys, it's really good stuff.  It will make your plane much easier to keep clean and the bugs come right off.  You'll be amazed at how "slick" the surface becomes and YES, you will gain several knots airspeed when you put it on.  Wax is a waste of time.  Be sure to get the plane completely clean before applying it.  Goes on like a wax, let it haze and then wipe it off.  It should wipe off really easy.  If not, then it's not dry enough - let it sit and come back to it.  Depending upon the temp and humidity it can take as little as 30 minutes and up to several hours to cure completely.  Once it does, it comes right off - does not require "buffing" or a lot of rubbing like wax.

I use this stuff on all my cars (including my show car) my boats and the Acclaim.  www.rejex.com  And no, I have nothing to do with the company.  I just use the product and have recommended it for years.

[Guest Anonymous]

Bump that thought.  I used it for the first time about a three months ago.  The only thing I would add is to make sure that you get all of the petro-grime off of the belly.  My first applicatiion did not last as long on the bottom because I only cleaned it with Simple Green and water.  On the second application I used a degreaser first, and THEN cleaned off the degreaser.  It seems to be holding up much better after that one.

[mooniac227]

Yep,  gotta get it COMPLETELY CLEAN before applying it.  It is designed to bond to the paint molecules so there can be nothing in the way.  Fact is, I tell people if they have ever waxed their car, boat, plane, etc before, then you should use a bit of Dawn dishwashing liquid in your water bucket (doesn't take a lot and DON'T make a habit of this) to strip off any other waxes and such before using the rejex.

[The-sky-captain]

After looking at different waxes I went with the Rejex a week or so ago. The bugs come off MUCH easier. Looks pretty too:)

[Jerry 5TJ]

I was looking through the CAFE foundation archives and ran across their study on speed gained by a good wax job.  The data are interesting for two reasons:  One, they provide a careful study of the impact of smooth wax on a Mooney.  Two, the article offers another nice view of the nose of the CAFE highly modified M20E, which will do better than 170 KTAS at 4000 feet at 2600 rpm.

See the report "Wax Effects on Drag" at CAFE Reports Page

 

[docket]

I use Rejex but i ain't buying it for speed.  I like it because it is easy to apply.