stabilizer trim with flaps down -- not enough?

[hallschuch]

Hi Guys,
I've recently started flying my series 7 and have noticed that while the elevator trims fine normally, when I apply full flaps it becomes quite nose-heavy even with full nose-up stabilizer trim. The trim does ease the pressure to a degree but its still a bit of a tug of war. Its not a huge issue but I'm wondering if anyone else is experiencing this...?
thanks,
Karl Schuch

[rv9ralph]

I think a lot of builders are using this:

Flap/Elevator Interconnect, Trim Assist Kit Series 5, 6, 7, Super Sport ,STi, Speedster Only
Helps reduce aft stick forces when making slow approaches to land. Specify Model
Series 5, 6, 7, & Super Sport Part # 9034-SP $110.00




on page 34 of the Kitfox Parts Catalog.

Ralph

[hallschuch]

Thanks Ralph -- I am definitely interested in that!

[jiott]

The other thing you can do is change the operating range of the stabilizer trim: instead of setting it per the build manual, set it so that when you go to full nose-up trim the front stabilizer tube is all the way at the bottom of the slot. This helps quite a bit, but does still not give you hands-off trim with full flaps. You give up some nose-down trim, but I have never needed it. Its an easy adjustment-try it.

[ken nougaret]

I have an SS7 with an O-200 on the nose(in other words, additional weight), and I can trim for full flaps and hands off. I have the elevator helper spring but that probably doesnt make a difference in this situation. My stab trim actuator is rigged per the manual.

[jiott]

This issue, not enough nose-up trim with full flaps, is why I strongly recommend adding another notch at 3/4 flaps in the flap detent bracket. It is easy to do before you install the bracket. 3/4 flaps is plenty for short fields and gives you less mushy control as well as hands-off trim.

[Dave S]

Agree with Jim that 3/4 flaps would be ideal. I have the trim assist spring but did not think about adding a 3/4 setting. I seldom use full flaps and almost always use 1/2 flaps since I have found that the additional full flap setting adds very little in the way of reducing stall speed but it is a great yaw generator in a crosswind. The trim assist package has some adjustment to customize to a person's plane. Half flaps with the assist spring gives a person hands off trim balance. I do have the manual trim tabs on the elevator and not the electric jack screw which may or may not change much for trim. I have also found that that how a person loads the baggage bay affects the need for trim assist (and a rearward CG load seems to help reduce stall speeds). I believe the ready to fly LS that kitfox makes is limited to half flaps if I recall correctly.

[jiott]

Dave, unless the factory has changed things recently, the ready-to-fly SLSA is not limited to 1/2 flaps. It has notches for 0, 1/2, and full flaps; however, the SLSA full flaps notch is equivalent to about 3/4 flaps compared to the E/AB kits. I think they should just standardize on the SLSA arrangement for everything including the kits. I was told by John several years ago that they wanted the SLSA to be more docile with full flaps, eliminating the trim issue and reducing some of the mushiness and giving better roll control with full flaps. At that time they kept the kits with more full flap angle because it gave a "little" better short field performance for those who wanted it. This conversation was about 5 years ago, so I am not sure its 100% accurate today.

[Dave S]

Jim,

Thanks for the clarification on the SLSA.