40% Ka-3 part scratch part kit

[Gene C]

Still a lot of tedious filleting to do before starting the fun part of detailing.

[lenb]

Wow Gene,
I finally had a chance to catch up on this thread and I'm completely blown away at your progress. The fuse looks great in the last photos above.

I'm looking forward to staying current now.

Len

[JimD]

Gene,

Something this great needs to be shared, so we just added a link on the home page of the website to your build!

Check it out here: https://www.scalesoaring.com/

[Gene C]

Thanks Jim,
Nothing like a little motivation.

[Gene C]

Started filleting the fuselage joints using small batches of 30 min epoxy and milled glass fiber. Applied with a small paint brush this may take a while as each batch of epoxy is allowed to set before proceeding. The process will reinforce the joints and provide a weld appearance after the fuselage is painted.

[Gene C]

The best laid plans go astray now and then. This just happens to be one of them. The spring back of the skid part was more than expected so the curve was increased. The top part was also added to the increased curve. The two parts will be glued together in the form and profited as a unit when dry. At least that’s the new plan at the moment.

[ARUP]

The epoxy 'welding' will look pretty cool! Yes... those pieces of hardwood sure have some springback. I have Ash on hand for making skids and it gets soaked overnight with water. Then I run hot water out of the tap over the piece before putting on the form and let it sit there for a couple of days.

[Gene C]

While on the way to display the 1/3 scale Cherokee along with Dean Gradwell's full size at the SSA convention at the request of the Vintage Sailplane Association, there was time at Montague CA. to test fit a few items to the fuselage of the Ka-3. Dean had a set of Ka-1 wings partially built that fit perfectly. He even pulled a 40% Axel pilot out of one of his ships to check the fit. By the smile on the pilots face, it will do.

[Gene C]

Just when I thought the airframe was complete there was more bracing to be added. This was found carousing the prints provided by the Vintage Sailplane Association. The structure reinforces the front skid mount and provides a mount for the rudder peddles on the full size.
Looking over the hardware provided in the Ka-1 kit it was necessary to change the 4mm full thread bolts. After trimming to size the straight shank bolts will be used to secure the wing mount plates in both the fuselage and wings (no more stress points).
The 6mm bolt was turned drilled and chamfered as a test for the lower wing strut fitting. Now all that is needed is to duplicate it a few times.
Then it was on to more of the fun stuff starting with the seat frame.

[Gene C]

Seat complete except for the retaining screw mount holes and varnish. Construction varied a bit but still within the concept of the Ka-3 print.

[Gene C]

Using parts from the Ka-1 kit as guides to set the 110 degree angle on test bulkheads to be fitted and checked on the Ka-3 fuselage frame. These will be used as templates to make the 5 ply bulkheads for the assembly after it all checks out. At this point it is a case of cut and past. Backing plates are also made from 1/8 ply for the front template. Two digital incidence meters were used to measure between the wing and stab insure alignment. Checking them a few times during the fitting also helps. This is only the beginning as once the permanent bulkheads are cut and fitted, it will be repeated at least twice more before epoxy is mixed.
Enough for today, My head is starting to hurt!

[ARUP]

Just take an aspirin and get busy you slacker! lol Beautiful work!

[Gene C]

Trust your eyes. After setting the incidence angle of the stabilizer in relation with the wing something did not look right. After sleeping on it, the next day I dough out an old balance incidence meter and rechecked the tail group. Sure enough it was off. I will not say that the digital incidence meter lied but provided an incorrect reading at the 55 degree angle of the stab. All is well now.
Parts have been made and just a bit more tweaking is required before epoxy is mixed.
At the same time the wing was blocked an a center to center measurement was made between the fuselage mount and wing mount for the wing strut fittings. More to come of this later on.

[Pgoldsmith]

Beautiful work Gene. "Inspirational...

[Gene C]

Ka-3 floor plate in 6 easy steps, more or less.

[Gene C]

While waiting on material for the V tail mounting, attention was turned to the preparation of mounting the wings. The Ka-1 wings provided for fitting were partially finished with the rear mount attach points yet to be set. The front mounts are preset in the wing build with the rear to be set when mounted an aligned to the fuselage center line.
The small adhesion area of the rear wing mount to ribs concerned me as there was no attachment provided to the drag spar. This meant that a shock load to the rear mount would only be absorbed by the width of the root and first rib of the wing. This felt inadequate so a filler bracket was positioned on the drag spar to lock in the front rear wing mount and transfer a shock load to both the ribs and drag spar.
Only time will tell if it works but I feel much better about the rear wing attachment now when the wings are finally mounted and the rear attach points are set with epoxy.

[Gene C]

The rear wing mounts are now fitted as they will be when epoxy in place. With the wings now mounted to the fuselage it's a matter of measuring and remeasuring. When all the zeros line up, then it will be time to mix epoxy and measure and remeasure again.

[gunny11]

Awesome construction and build. Been watching silently. What is the base wood material of the wing strut?

[Gene C]

gunny,
The wing struts will be made up of 0.035 wall steel streamline tubing. Yes we are talking aircraft quality material here. The attach points at each end will be silver soldered to the streamline tubing not unlike the full size Ka-3.