Questions on wing area and LA 46

Hi all,

As a way of introducing myself, I am another New Mexico modeler that builds Roadrunners and I-beams. My greatest claim to fame is I flew in a contest at Las Cruces where we had gusts of thirty to forty mph. Had to stop because the plane, a Mustunt, would not complete a lap. Larry Cunningham was there and will certify I was insane.

Couple of questions. In my senior years, sometimes get confused. When we give a wing area for a plane, that includes the area contributed by the flaps, correct? When we say the flaps are a percentage of the wing area, this means a percentage of the total area, wings plus flaps?

Second question. I see references to a definitive thread ref setting up a LA 46. Think it was started by Doug Moon, or finished by him. Can someone point me to it? I am up to page 25 in the archives, and still have not seen it.

Presently living in Albuquerque, but will be returning to Las Cruces in a few weeks. Have flown at Los Alamos (7300 ft altitude) so can probably answer any questions anyone may have about flying at altitude. 1st answer is nitromethane, and 2nd is wing area. Hence the Roadrunner.

Thanks,
Gary

Wing area includes flaps. Divide the flap area by the total area to get our percentage. The usual practice is to include the portion in the fuselage even though this is not "active" area.

I'll certify the Colonel, all right!

Welcome back, Gary.

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Don't walk in front of me. I may not follow.
Don't walk behind me. I may not lead.
Walk beside me. And just be my friend." -Albert Camus

Here is one, it contains most of what you need.

http://www.clstunt.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=4753&forum=DCForumID1

Gary:

Good to know that you are still out there. We would like to see you in Tucson again. September 25 & 26 in our Fall contest. If you could make it, it would be great.

Anyway, depending on venturi size and nitro content an LA 46 will develope a wide range of power posibilities. I would say that 700 Sq. In. is pushing the envelope, but, if this size plane is lite a combination of venturi and nitro will give you good results.

Weight:

40 to 50 oz is your target weight.

Wing Area:

550 to 670 Sq. In

Nitro:

At locations below 1000 Ft elevation, 5% nitro fuel.
At locations between 1001 ft to 5000 ft 10% to 15% nitor or even as high as high as 20%

Venturi Size:

OS makes two sizes of venturi for the 40 FP which fit the LA 40 and 46. One is the small at (6.5MM or .265") and the other is the large at (7.2MM or .283"). Both are sill availabe from Tower Hobbies.

Since you fly in the higher altitudes of New Mexico you should use the large venturi in combination with 10% to 15% fuel. Same at Las Cruses. If you every make it back to Phoenix, the large venturi in combination with 5% to 10% nitor fuel will work.

Run Time:

OS LA 46 using the large venturi on 10% fuel will use 4.5 oz of fuel to make it thru the stunt pattern with about 10 laps left. 5 oz is better at the lower altitudes because 4.5 is pushing it a bit. A 5 oz tank gives you more flexability as you move around to different altitudes.

If you have questions, contact me at my e:mail address [email protected]

Hope this helps

Robin S.
8/9/04