8178

My Feedback: (17)

The fixed gear version of the kit uses a very clever plywood wing tongue for the front of the wing but because I’m using retracts I had to use dowels. The next step was drilling the front of the wing for the wing dowels. I carefully positioned the wing on the fuselage and by using pencil lines of the fuselage former holes I transferred the dowel positions to the front of the wing. The back wing bolt was a little more tricky because the thread hole was already on the former. I threaded a wing bolt into the mount from the inside facing out so it would just contact the wing. I put a piece on masking tape on the area of the contact spot on the wing. I then carefully aligned the wing on the fuse and pressed down on the back of the wing so the wing bolt would make a mark on the tape. I drilled through the wing on the tape mark for the wing hold down bolt. Next was making the back wing fairing. On the originals I used Micro-balloons mixed with epoxy but this time I decided to use balsa.


To be continued..

8178

My Feedback: (17)

More images of the wing. Not all of the sanding is complete yet.

To be continued..

8178

My Feedback: (17)

I used scrap from the wing tip blocks for the front of the wing and a small amount of Micro-balloons and epoxy. View of the back part of the wing before the Micro-balloons and epoxy filets and final sanding. The edge of the balsa on the front and back of the wing is capped 1/32” plywood to give it a hard edge.

To be continued..

8178

My Feedback: (17)

I taped off the area under the canopy and painted it black. I located the canopy on the fuselage and made a fillet around the lower edge of the canopy and the fuselage with fine glass cloth and epoxy. After the epoxy set it was sanded smooth and then a thin layer of Micro-balloons and epoxy were added. The Micro-balloons and epoxy were sanded to give a smooth transition between the fuselage and the canopy. There is a 1/16” breather hole in the fuselage under the very back of the canopy.

To be continued..

8178

My Feedback: (17)

Me too!

8178

My Feedback: (17)

As I mentioned earlier the original had a Webra 61 Black Head and this kit was also setup for the Webra. My son has all my old Webras and I could use them but I decided it wouldn’t hurt to have more power. I decided that I would use one of my Irvine 61 ABC engines. It is a little longer than the Webra but with a little work on the Hays mount I was able to move it back 1/8” to make up for the difference in length. Most SPA guys are using four strokes and on a new kit the firewall could be positioned further back to gain the needed space. The kit uses a neat mounting system for the motor mount and fuel tank. The front of the tank mount holds the blind nuts for the engine mount bolts. I had to modify the system slightly to make room for the nose gear retract unit air cylinder. I like to mount my engines to the right side but the engine can be mounted upright or any position in between. I haven’t cut out the fuselage for the Irvine carb yet.

To be continued..

8178

My Feedback: (17)

Images of the fuel tank with new fuel lines.

To be continued..

8178

My Feedback: (17)

Image of the Irvine engine installed. Just for nostalgia I’m using the Du-Bro muffler like I had on the original. Extra baffles of course!

To be continued..

8178

My Feedback: (17)

The horizontal and vertical stab is cut from 3/8” light balsa and needs to be sanded to an airfoil shape. I marked off two lines on the front edges that were 1/8” apart from the center line. I then started the airfoil shape from about 1.5” back from the leading edge and then rounded off the very front.

To be continued..

8178

My Feedback: (17)

The vertical stab is made from four pieces of 3/8" light balsa. Two pieces are butt joined together for the main vertical part, then one piece for the front part on the fuselage and then a small piece at the angle change on the lower front part of the stab. I glued the pieces together on my bench top to keep them straight.

To be continued..

8178

My Feedback: (17)

Next the horizontal stab was test fitted on the fuselage. A scrap piece of 3/8” balsa was inserted in the stab key and down into the back of the fuselage to hold the back of the stab in alignment. Careful measurements were made from the front center of the fuselage to the back outside stab on each side to make sure the stab was square with the fuselage center line. The stab was cross checked with the wing by measuring between each stab tip and each wing tip. When everything checked out a pencil mark was made from the front part of the stab and onto the top of the fuselage for an alignment key. The stab was also checked to make sure it was in full contact with the top of the fuselage and was parallel with the wing. The stab was removed and the top of the fuselage was coated with epoxy. The stab was re-installed and taped in the front to hold the alignment. All the alignments were rechecked to make sure nothing changed while the epoxy setup. These alignment checks of the stab and fuselage and wing are critical to making a great flying aircraft.

To be continued..

8178

My Feedback: (17)

The final sanding was completed on the vertical stab assembly. Using a 3’ straight edge a pencil line was projected from each side of the horizontal stab key out to behind the canopy and aligned with the center line of the fuselage. These lines are used to make sure that the vertical stab will be square with horizontal stab and the fuselage center line. The vertical stab was test fitted to make sure that it was in full contact with the horizontal stab and the top of the fuselage. The bottom of the vertical stab was coated with epoxy and some spread along between the pencil lines on the horizontal stab. The vertical stab was installed and aligned with the pencil lines and taped down to the top of the fuselage. A square was used on the top of the horizontal stab to check that the vertical stab was positioned squarely with the horizontal stab. A piece of tape was used to hold the stab in alignment while the epoxy setup.

To be continued..

8178

My Feedback: (17)

After the epoxy was setup on the stabs I mixed some Micro-balloons and epoxy and made small radius fillets on both sides of the vertical stab and around both sides of the horizontal stab. The fillets look good but also add more strength to the stab mount. I need to sand the fillets next. I’m using K&B Micro-balloons but I’m not sure if they are still available.

To be continued..

8178

My Feedback: (17)

Now that the vertical stabilizer is glued in place the bottom of the rudder can be shaped to the bottom of the fuselage. Note the cross grain balsa at the bottom of the rudder.

To be continued..

8178

My Feedback: (17)

After the Micro-balloons and epoxy have setup hard the stab fillets can be sanded. These will need a follow-up coat of Micro-balloons and epoxy in a few places but it can be blended in easily.

To be continued..

8178

My Feedback: (17)

Some more detail on the engine and fuel tank mount. In the attached image the balsa strip represents the firewall. The Hays engine mount is on the front side of the firewall. The fuel tank mount is on the back side of the firewall and has a plywood piece that holds the blind nuts for the motor mount bolts and holds the front of the fuel tank. The firewall has a round hole in the center for the fuel lines. On this kit I had to space the fuel tank back to make space for the retract gear air cylinder. You can see how I routed the fuel lines to one side to clear the cylinder. I did this all thirty years ago so I’m somewhat impressed that I can still remember how and why I did it this way. I guess you could call this a true SPA aircraft because the main airframe has a thirty year old serial number! Although SPA does not allow retracts to be retracted during competition :-(

To be continued..

tommy s

My Feedback: (55)

I can tell you know how to build a pattern ship the way we used to build them.
Nice work !

tommy s

8178

My Feedback: (17)

Thanks for the positive comment Tommy s. I take a lot of pride in building aircraft and what could be more fun than getting a thirty year old Kwik Fli in the air.

8178

My Feedback: (17)

This post is a little out of sequence but I thought I would cover it anyhow. All of the control surfaces on my Kwik Fli are hinged with the good old standard size Du-Bro hinges. I like them because they are very strong and when glued in with epoxy they make a ridged, slop free, and long lasting hinge line. After all this Kwik Fli could be around for another thirty years! Du-Bro makes a tool that automatically finds the center of the control surface and has tools for cutting the hinge slot. See images below.

To be continued..

8178

My Feedback: (17)

After the basic hinge slot is cut out I make a countersunk area in the slot so the center of the hinge can be recessed into the control surface. Note how the center of the hinge protrudes into the control surface.

To be continued..

8178

My Feedback: (17)

Ok, we are back in the build sequence! The control surfaces are hinged and have been shaped to the horizontal and vertical stab. The next step is to shape the leading edges of the control surfaces so they can deflect when the hinges are glued in place. I prefer to make the leading edge V shaped rather than round. I want to keep the center line of the control surface that is lined up with the hinge line the sharp end of the V. If it is done correctly there will not be any gap at the hinge line but the control surface will move freely and will be self sealing.

To be continued..

8178

My Feedback: (17)

I have a notch cut in the rudder so I can use I wire joiner between the elevators. My original used a heavy coat hanger wire as a joiner. I’m not sure yet if I’m going with the 70s approach or the 80s setup like on my Tipo with a split push rod to both elevators.

To be continued..

8178

My Feedback: (17)

I mentioned earlier that my foam aileron cutout installation is a modification to the kit. The standard kit uses 1 ½” wide balsa ailerons and on this build (re-build?) I went back to the 1 ½” wide ailerons as per the original plans. Please see the images below that show more detail of the finished aileron.

To be continued..

8178

My Feedback: (17)

Image of my original plans for the kit dated 3/6/70. A little yellow after 30 years but still very usable. I understand that the latest 2005 version of the kits come with updated plans and show the aircraft as it was approved by SPA http://www.seniorpattern.com/ .

To be continued..

8178

My Feedback: (17)

I started working on the engine installation and checking the clearance around the carb. I like to keep the opening around the engine as small as possible but because the opening had all ready been cut for the shape of the Webra Black Head I had limited options on the Irvine installation. The tight opening requires the carb to be removed to install or remove the engine but I like the look of the tightly closed in fuselage around the engine. I decided not to try to form new glass in the open areas that were not need for the Irvine and just make one cut near the carb. There are some cracks at the very front of the fuselage that are part of the UPS shipping damage that I need to address next. The before and after carb clearance images are below.