kitfox mk 2 . severe turn to left !!!

[mikegregory]

Hi all . I've just became the owner of a kitfox mk 2 with jabiru 2.2 engine . On my initial test flight . On climb out I encountered severe roll to the left ! I had to input quite firm right aileron to compensate . ( slip ball centred) . When power reduced for cruise . The roll to left is less severe , but still there . I cannot fly hands of . Yet when decending at nearer idle & at lower speed . The wings stay more or less level . Is this severe engine torque ? Or do I need to adjust the threaded bit on the right wing strut ? Or could it be something else ? All info & advice gratefully received
mike

[Esser]

Hi Mike,

Welcome to the forum. Someone with more experience than me may chime in but what I would do is completely level your aircraft longitudinally and latitudinally. Then take a 4 foot level and check your dihedral. It should be 1 degree. I think that is about 13/16" over 4 feet. Once you are sure both your wings dihedral is set correctly, check level at your wing roots and then at your wing tips. the Tips should have one degree of washout on the model 5,6,7s but I'm not sure about the earlier models. I am sure it is similar though.

Anytime anything is out, you can adjust your rod ends at the spar attach brackets to find the settings you desire.

[Jfquebec]

ya, you are right Josh...and if is homemade engine mount,the engine are never straight for prop torque,he need to be offset....

[Esser]

No problem. Also before you do that, you may want to double check your flaperon rigging. I don't have any of the specs for the Model 2 but I'm sure someone will chime in. And like JF says, if all that stuff checks out, you may have to modify your mount but I think you would have more of a rudder issue if that were the case.

[Jfquebec]

One other thing to check....my classic 4 have one side more higher on elevator...is aprox 1/2" i...if i put my elevator at horizontal ,you can see the left side more higher.....

[mikegregory]

Just wondering ? Which is best to try first . Adjust the incidence ? Or fit an aileron trim tab ? If so . Where should it be put ? What size etc ? & how much deflection would be effective ? If I stick with changing incidence on threaded part of wing strut . How much do I wind it out ? To have an effect ? ?

[Esser]

Hi Mike, I would level your plane and take all your measurements with a level and see how different the two wings are. That will give you a good place of where to start.

[Dave S]

Hi Mike,

I agree that the first thing to do is to assure the rigging is as close to the specification as possible meaning wing dihedral, wing washout, flaperon mixer settings (there is at least one kitfox incident where the investigator - correctly or incorrectly, blamed the incident on the out of spec flaperon assembly/settings)

Once a person is assured the rigging is right, it would be time to work with the fine tuning - that is where many of us have solved slight roll tendencies by adjusting the rod ends (not all that uncommon in a new aircraft).

FWIW - Our S7 had a left roll tendency on first flight...fine tuning the wing washout by adjusting lift strut rod ends - one rod end at a time with 1/2 to 1 turn before flight testing again.

What constitutes a sever roll might well be percieved differently by different people.

With your observation that with power the problem is manifest; but, power off it doesn't happen causes me to think a person may also want to check the aligment and rigging of the tail too....and how much rudder a person needs to use.

I found that any testing and changes are best done in small increments and one at a time so a person can tell if the trend is going the right way and there are no really big bad suprises.

Good thing to keep in mind....none of us are there with you and ultimately the person working on the plane is the only one in a position to account for items that may be totally unknown to distant observers.

Best wishes in finding the problem.

Sincerely,
Dave S
KF7 Trigear Flying
912ULS Warp Drive

St Paul, MN

[mikegregory]

Thanks guys most appreciated .