Dan & Cole's 1050 Build

[Eric Page]

...I am interested in any detail if metalwork is needed in the tailwheel mounting area.

You can see what I did to my Series 5 here. This modification significantly strengthens the tailwheel spring attach plate, as well as the overall weldment at the base of the tail assembly.

Note the rudder pedal torque tube reinforcements shown in that post as well. I don't know if that's a thing for the Model 3, but perhaps someone who knows more about them than I do can chime in on that subject.

[jiott]

I would like to add my voice to strengthening the tailwheel attach area, mainly the rearmost bracket. In my opinion this is hands down the weakest area on the Kitfox frame. Anything you can do to reinforce and/or gusset this area while it is open and exposed like this is well worth the effort. The problem is not so much vertical loads from hard landings, but it is side or twisting loads that occur on landing on rough surfaces that try to kick the tailwheel sideways and back and forth. I have repaired this area to fix cracks and worse twice now, always after a very rough field landing. Believe me, its not easy to do this repair in this confined area with fabric covering close by. I have heard that the TK tailwheel assembly is somewhat more susceptible to side load damage that the plain spring assembly. Keeping your tailwheel in the air as long as possible when landing on rough surfaces will help a lot in avoiding damage. The TK shock suspension is great for cushioning vertical loads, but does nothing for side loads. Just my opinion and actual experience.

Also, notice that the Kitfox factory has has reinforced this area with a triangular gusset on that rear clamp bracket on their later SS7 models.

[D&CJohnson]

Thank you Jim and Eric.
I will take the TK1 tailwheel assembly out to the shop and try to incorporate some strengthening to mounts. I took screenshots of your photos. Anyone else, please be sure to add your advice and photos of your work. The pedals will be reinforced also.

[Av8r_Sed]

Trent Palmer recently posted a YouTube video which showed the tailwheel mounting plate gusseting he had added to the Freedom Fox.

[D&CJohnson]

Trent Palmer recently posted a YouTube video which showed the tailwheel mounting plate gusseting he had added to the Freedom Fox.

thank you. I?ll find that.

[D&CJohnson]

IMG_2768.jpg
Elevator complete except servo mounting tabs. Floorboards here but will need finish trimming.
IMG_6832.jpg

[FoxbuilderWill]

IMG_2768.jpg
Elevator complete except servo mounting tabs. Floorboards here but will need finish trimming.
IMG_6832.jpg

Just curious why you're adding the balance tab to the rudder and not the elevator?

[D&CJohnson]

Just curious why you're adding the balance tab to the rudder and not the elevator?

Simplicity. Personal preference I suppose.

We had the early short rudder so we wanted more height/yaw stability. Using a balance tab design let us accomplish that without much change to the vertical stab. We are adding a tube for the razorback hoping that helps as well. This was really secondary to elevator effectiveness because I was not bothered by the neutral yaw stability of my model 3.

Wanting more elevator effectiveness is our primary reason for cutting metal. Adding balance tabs would require widening the elevator and/or cutting down the width of the horizontal stab. Widening the elevator would not be desirable for hangar/trailering. I did not want to cut down the width of the horizontal stab either so we just added 5 inches to the chord of the elevator and rudder alike.

I have an extra servo and a piece of the trim tab left over so I will add rudder trim as well. I have some opinion on this because my Waco does not have rudder trim and it is a PIA.
Dan

[D&CJohnson]

Mark and I put in a few hours on the Fox today. I was metal trimmer and human clamp while he did all the real work with the torch. We got a lot done. We added the tabs to hold the servo in the Elevator, tack welded the channel and tubing in the Rudder to hold the trim tab and servo. We fit the razorback and tacked it in place. Finally we cut the steel for reinforcing the tailwheel attachment and tacked the vertical part in place. we made a bottom plate that is not pictured. You may notice a couple extra tubes in the aft fuselage as well.

We need to make some tabs to hold the rudder servo in place and Mark will finish weld everything this week. The only other metalwork planned at this point is reinforcement of the rudder pedals. I should have it home soon and will start prepping to get paint or powdercoat on the fuselage.

KF1.jpg
KF2.jpg
KF3.jpg

[atosrider]

for the elevator extension, I would be concerned about potential for flutter, you put a counter=balance on the rudder but .. adding force and weight that far out from the hinge points on the elevator seems to be stepping into the unknown ...
there have been several posts of damage to the carry-through truss under your knees, from heavy arrivals ..
the original wing struts in my 4-1050 rebuild were seriously corroded from the jury strut attachment point technique that allows water to enter and get trapped at the bottom of the strut, plan accordingly, and maybe even go for the heavier version now offered by the factory .. likewise for the horizontal stab struts, something the Brits considered a deal breaker for registration over there ...
the original design has lots of pop rivets going into the frame, for the windshield/skylight and that useless fiberglass seat .. weld some tabs to mount to instead .. maybe add a stiffener to the wing carry-through ... I cut the fiberglass seat in half, used dual velcro straps to keep them off the control linkage, adel clamps instead of pop rivets, and rotated the pilot seat back forward with a spacer and gained a bit of shoulder room ..
you've probably found out the need for a new style motor mount ... larger cavity for the larger starter motor compared to the 80hp ...
and a topic that seems to be taboo in the land of love for the factory, powder coat hides underlying rust .. my rebuild got walnut shell blasting and epoxy primer, endura 2 part primer sticks something unbelievable ...
and made a frame for larger windows each side, can be removed if there is a big maintenance item to do ..
fuel tanks can be a problem .. there's so much info available on this forum ...
and that's a good idea to hold off on the engine monitoring device, it would be obsolete before needed - hope you can prove that prediction wrong !!
buying polyfiber before the next price increase is a good idea, but watch out for the shelf life ...