Currently working on a 4*40 kit and read up on suggestions and tips on many web sites and the forums here. LOTS of great info! One of the modifications I would like to incorporate is the larger rudder mentioned by some. Somewhere I read that the 4*40 has a tendancy to drop the nose when using the rudder, and I was wondering if making the rudder larger will make this tendancy worse. Anybody with larger 4* rudders out there notice this?

There was also a mention of a rudder modification made by the original designer when he designed his next plane that eliminated this tendancy. Unfortunatley, I haven't been able to find a description of this modification. Anybody know what this modification is and can provide a sketch to help guide me in my search for a better rudder?

This thing is sure going together a lot faster than the Kadet Senior did

Here is a link to the Venture 60. The plane that was redesigned by the designer of the 4 * series.

http://www.btemodels.com/venture.html

If you look at the Frequently Asked Questions page using the link posted above you will see that Bruce addresses the reason for the improved tail design. I did a quick search thru RCU for posts discussing this in some detail but didn't come up with any- but I know they are out there 'cause I remember seeing several about a year ago. It seems to me that part of the cause is actually the vertical position of the stab in relation to the wing, but I don't trust my memory that much.

Anyway rudder performance on the 4* is not a real issue unless you are absolutely determined to make coordinated aileron/rudder turns. The rudder as designed is fine for both ground steering and basic acrobatics. And many floks have successfully built bigger ones to get improved response. If you want a bigger rudder then go for it. I'm sure the plane will fly just fine.

The rudder issue is primarily one that deals with a very bad tuck to the gear when attempting to execute a knife edge. I emailed Bruce and asked about this and he informed me that the original 4 Star design had the horizontal stab located too high on the fuse which resulted in this tendancy. My question was how should I modify a 4 Star 60 to get it to fly a good knife edge like the BTE Venture 60, Bruce's reply was to move the stab about 3/4 of an inch down. Basically this puts it on the engine thrust line, built stock the stab is well above it.

Adding area to the rudder also helps in my experience if you like to do maneuvers like hammerheads or stall turns. One thing you should NOT do is take the dihederal out of the wing if you are attempting to improve the knife edge characteristics since the design needs some to reduce roll coupling tendancies.

The tendency to tuck towards the landing gear during knife edge is rather frustrating on the 4* (you need to hold up to track straight). And an enlarged rudder would help it hold knife edge. I have the greatest possible throw on my rudder, and it still will barely hold knife edge for a few hundred feet, then it starts dropping.

I can do stall turns fine, but it requires a quick blip of throttle at the top, and you need to hold a little up elevator as well.

If I ever build the kit, I will lower the horizontal and add to the rudder.
Dennis-