A tinkerers Toys [Archive] - TeamKitfox Forums

HighWing

01-10-2017, 07:41 PM

Some kind words from you guys have prompted me to start this thread. I plan on posting some of the Modifications I have done mainly on Model IV number two, but possibly some from No. 1 also.

I welcome comments and the critiques that come to mind as well. Also if any of you have had the "Tinker" addiction prompt you to make mods, feel free to share

Since we all tend to start in the back, That will be where I will start.

Post Number 1 -
This will focus on the fairings and gap seals I put on the empennage.

I did it as well on 96KL, but this time a bit different in design. I wanted an airfoil from leading edge to trailing edge without the hour glass shape at the hinge lines. The vertical stabilizer to rudder was fairly simple as the rod end hinge design gave ample space for a complete arc on the leading edge of the rudder. The hinge at the horizontal stabilizer to elevator was the challenge due to the limited space provided by the welded tube hinge design. This required some real effort. I made up some molds to use to get several shapes I could use. Some fit as molded, some needed trimming and re working while in place to provide an unencumbered range of movemtent - both vertical and horizontal. All ribs were fabricated from 1/4" LAST-A-FOAM from ACS. After cutting, the foam was coated both sides with a medium weight fiberglass cloth and epoxy resin. After final trimming, the edges were coated with "Micro" and sanded smooth.After covering, I did riblace for reasons that will be explained later.

airlina

01-11-2017, 03:58 AM

lowell, thanks for sharing your ingenuity with the rest of us. After the first installment, I can' wait to see what else you have come up with. Great job on the empennage gap seals. Bruce N199CL

av8rps

01-11-2017, 08:01 PM

Ditto, ditto... !!

Keep em coming. This is some great stuff Lowell!

Paul Z

01-11-2017, 08:22 PM

Lowell,

Do you have a picture of the tool to make the fiberglass fairing on the horizontal stabilizer? Very impressive and simple design to build the molds used to fabricate the gap fill parts.

Paul Zimmermann

HighWing

01-11-2017, 10:23 PM

HighWing

01-11-2017, 10:45 PM

Post Number 2
Elevator trim is a must in my mind.
On my first Model IV, I ordered the Speedster Elevator and it worked well. This time elevator trim became an an add on. The first thing I did was make a trim tab by folding a piece of aluminum to the desired dimensions and shape. I wanted it to fit between the two outer welded in tubular ribs. The chord of the tab then determined the cut out dimension of the middle rib. I found that if the trailing edge is cut out first, the weld stresses would result in the hinge spar bending toward the trailing edge, so the first cut was to remove some of the #2 welded rib to clear the tab and for the welding of the square tubing. After the half inch square tube was welded in, the trailing edge could be cut out without distortion to the spar. Piano hinge was used to connect the trim tab to the square tube. The servo was attached by welding in tabs – one offset to secure the servo. The 4-40 screws were welded to the tabs to avoid the need for a wrench on top of the tab. A servo cover was made to cover the servo at the bottom of the elevator. The attachment arm for the servo at the trim tab was made by hysoling a couple of pieces of aluminum angle together to form a T, then cutting and sanding to the final shape.

With the gap seal and trim tabs, I found elevator authority a nonissue with three point landings.

As a side note, a local pilot – Avid - wanted a different profile on his elevator for additional chord and brought some drawings. I helped him with the assembly and liked the design a lot. I would be tempted to use the design if building again. Two photos are attached to give an idea of that design. The first shows the trailing edge tube and its relationship to the existing profile of the Kitfox elevator giving significant additional surface area. The second shows aweldding jig with parts in place. One thing I really liked about it is the hinge on the top surface rather than between elevator and trim tab - much simpler.

Dave S

01-12-2017, 08:00 AM

Although I have never achieved the status of "tinkeringhood" that Lowell has, wanted to take Lowell's invitation to share a very small effort in that direction.

Back a while this year I decided to add a rudder trim....probably no big deal except that some of the more elegant designs that were done by builders on this list who made their modification before the fabric was on......too late for that in my case so it had to be an add on.

Here's some photos and a description of my thought processes.

1) Our friend from Oz on the list was kind enough to share what tab size and position on the rudder worked for him. Both measurements worked out perfectly.

2) Checking how simple add on rudder trim tabs are done on other aircraft, with one observation that normal certificated tube and fabric aircraft which have thick trailing edges due to the tube frame often have the tab on the right side, bent around behind the trailing edge so I decided to try that. I figure the tab is "lifting" the rudder to the right anyway and this installation allowed for less of the tab sticking out in the airstream on the left side.

3) Rather than having a sharp bend in the tab, decided to go with a curved bend which theoretically might allow for a smoother air flow over the tab.

4) In fastening the tab to the rudder I decided to go with the 3M double sided high strength trim tape....since it comes in 1/2" wide strips, it was necessary to use two strips to account for the one inch wide contact. One caveat with the adhesive method is the paint must have been prepared and applied correctly so there is no delamination of the paint layers....thought about that and it has not been a problem. Considered the traditional drill the tube and use screws; but, I like to stay away from that to avoid potential moisture penetration of the tubing.

5) The two holes in the corner of the tab are not some super-secret-vortex-generators....just a practical way to support the tab for painting before it was stuck on the plane :o

The last photo is looking up from the bottom to show the amount of curvature which resulted in a hands and feet off cruise.

HighWing

01-12-2017, 10:31 AM

Dave,
I like your thinking. My next post will cover the very complicated rudder trim, I just had to try. More later on that.

HighWing

01-12-2017, 06:22 PM

Post Number 3
Rudder trim is an often mentioned subject.
Long before the start of Model IV #2, I had fantasized on the “Wright” technique of wing warping and its possible use for rudder trim. I needed to at least try it. The plan was to make two bottom ribs out of a flexible material, tying them together and having something move the two piece bundle right or left to create an airfoil shape in the desired lift side.
One of my favorite structural materials – Carbon Fiber arrow blanks were used for the ribs. They were tied together at the cam actuators by drilling adjacent holes and using Hysol to glue in a short length of control cable across the gap. To keep the ends in place against the steel structure, I welded projections on to the tubing and threaded the ends of the carbon fiber tubes on the nubs. I also fabricated thin aluminum U channels to be glued on the outside of the tubular ribs to give a flat surface for the fabric to be glued to.
Carbon fiber tubes were also used to connect the cams needed to control the two ribs to conserve weight along with welded steel bell cranks as needed. The servo was attached in a fashion similar as that used on the elevator trim. I decided to rib lace to help support the tubular ribs as they moved against each other. For continuity, I rib laced the entire empennage.

The system works! And to answer the question, “Was it worth the effort?” I have to say yes from the tinkerer’s point of view. The idea has been put to the test and essentially put to rest. However as Dave and others will likely suggest, movable rudder trim is pretty much a nonessential item with our airplanes – sort of a set it and forget it item. Thinking about it, if I were to do the rib warp again, I would have a little hole, probably in an extension of the leading edge fiberglass, that I could insert an Allen wrench into to make fine adjustments and save the weight and complexity of the electric servo.

The last two pictures show the relative curvatures of the two sides needed for the same result Dave and many others have gotten with a simple tab. I do like the clean, though

n85ae

01-13-2017, 11:42 AM

Nice stuff here Lowell! I like what I see,

Jeff

HighWing

01-13-2017, 10:02 PM

Post Number 4
A buddies 604 lb. empty weight Model IV was in the back of my mind during my entire build. With all the gadgets I was putting on my airframe, I wanted to subtract some weight. I had heard that the extruded PVC lift strut fairings could add up to 14 lbs. so thought of ways to possibly reduce that. At one of the factory fly-ins, I saw Dan Denney’s highly modified Kitfox and noticed that he had aluminum fairings, so that became my challenge. Then watching a neighbor having a new roof put on with the gutters rolled from a coil of sheet aluminum established my goal. I started working on a rolling mill.

My first goal was to roll a sharp angle at the trailing edge to capture the free trailing edge to avoid what happens sometimes with the aluminum flaperon. Sadly, that is about as far as I got as personal pressures wanted the airplane flying. After rolling a section I used a brake to fold an angle mid span on the aluminum and after folding, that became my airfoil. My shear and brake only had a 30 inch capacity, so there needed to be four lengths of fairing for each section of lift strut – sixteen in all. One thing became clear early that presented an unexpected challenge. When a section of the fairing was folded, being held together with the angled trailing edge, it was not stable. It could be twisted into a near helix just by rotating leading edge against trailing edge. If not careful, this could result in a twist on the fairings. The PVC sections being long enough to cover the entire span avoided this problem, but it still was a slight possibility if not checked carefully. The solution was to glue one length together with great care, ensuring it being perfectly straight. Then an assembly jig was made from that section. This also provided an unexpected benefit – mentioned later. To hold the fairing in place on the lift strut foam spacers were cut using a home made punch.

The lift strut was supported vertically, Wing end down. A section of aluminum fairing was placed over the lift strut and held in place with a complete section of foam at the bottom end, then the clamping fixture was placed and clamped to secure the partial foam section against the strut on the upper end. A 1 oz. mix of twopart Urethane foam was then poured into the fairing shape and allowed to cure. The clamping fixture was then moved to the next location and the process was repeated. I had learned that the Urethane foam was very adhesive and found no need to add adhesive to the aft joint. The benefit of using the clamping jig was when I made sure that each joint between fairing sections had the clamping fixture overlapping to help form a smooth joint. Once complete, the trim to allow for wing folding was accomplished and the V connection covered with a small fiberglass section faired with Micro. The final finishing touch was to form and glue on thin sections of aluminum to cover the joints between sections. The aluminum I used was .010 thick. Early I felt the need to placard with a NO PUSH decal, but decided it was not necessary as the Urethane foam gives a really firm feel to the fairings. Before and after weights indicated that the fairings were very close to 5lbs. total.

PNWJARED

01-14-2017, 03:14 PM

HighWing

Excellent Post. Very Clean! Very Cool! way to up the bar for the rest of us!

I assume the results are evident as well.

HighWing

01-16-2017, 07:13 PM

Post Number 5.
When I began this project, there was an article in Kitplanes by the electronics guru, Jim Weir. In it he explained the electrical needs of LED bulbs and explained that for constant light output they needed constant current rather than a set voltage. He then offered a power supply in schematic form. I was hooked. When I finished my first one, I was surprised how large it was. Later experience with DC to DC voltage converters proved the concept. To change from 12 V. to the voltage needed for a typical LED required first conversion to AC to feed a transformer, then back to DC at the new voltage. Without adequate filtering, these can be really noisy. Flying under Sport Pilot, I really didn’t need the lights, but wanted them just in case.
The first pictures will show how I mounted the aft position lights. To avoid complexity, at least so I thought, I decided to position them on both sides of the rudder so there wouldn’t be a possibility of rudder shadowing. For that I needed some custom lenses. The lenses were made using a vacuum forming technique I learned in the dental office – Mouth guards and bleaching trays. No longer having the equipment, but knowing how it worked meant searching for components and building my own.

The lights on the wing tips used the same mounting method that I used on 96KL, but using the LEDs rather than the big bulbs. While working at United Airlines as a fueler, I noticed on the B-727s they had an interesting wing tip design that I adapted to the Kitfox. A “door” was cut out of the fiberglass. Then a lip was added to provide positive positioning with screws into nut plates for attachment. A lens was fabricated using heated Lexan forced over a plug made from the wing tip for shape. This was then glued to the “door”. A note on heat forming Lexan (Polycarbonate). A quirk of the material is that it is extremely hydrophilic – it absorbs significant quantities of water. To heat form it successfully, it needs to be dried in an oven for a time determined by its thickness. Otherwise it will look really interesting after forming - lots of steam bubbles within the plastic - large and small.

jrevens

01-16-2017, 07:26 PM

As usual, really excellent, Lowell! You're a man after my own heart, but you are the king of innovation, making your own tooling, etc., etc.!! I love seeing what you have done!

HighWing

01-17-2017, 11:24 PM

Post Number 6 Landing Gear

The landing gear came as a suggestion from a friend. He gave me some numbers and that became the goal – two inches taller at the firewall and 70 inches beween the brake mounting pads. To ensure the same fore aft relation with the new gear legs as the original bungee gear, it was important that the axles be exactly under the same point on the airframe so that was the first goal. The fuselage was positioned in three point the tail supported by the tail wheel and a support frame forward that held the bungee gear with the axles where they would be if in the wheels. A rail like structure was made as precisely as possible using inverted angle iron and it was fixed to the floor perpendicular to the long axis of the fuselage with Bondo. “A” frames with inverted Vs as feet to slide on the rails provided the means for adjusting the width of the gear legs with no fore and aft deviation and removable supports that fit into the inverted Vs provided the means to increase the gear leg lengths as desired. The A frame adjustment support dimensions were determined to get the desired 2” additional height at the firewall - increased leg length when removed. Then it was a matter of creating landing gear weldments that closed the gap between the axle mounted on the A frames and the gear leg attachments on the bottom of the fuselage. These weldments became the landing gear legs the spring struts and the cabane. The fairings were of thin aluminum to conserve weight.

A note: with the desire for accuracy, great care was taken to ensure proper tracking if wheels were on the axles. It was found, as many suggest, that the original gear (1992) was significantly toed in and appropriate adjustments were made to correct that.

HighWing

01-18-2017, 11:04 PM

Post number 7 Baggage Area, Hat Rack, Shoulder Harness Attach Points

The baggage area is another topic that comes up a lot. Most of the talk is increasing capacity. My goals included that as well as reducing weight and improving accessibility. The floor was made up of Fiberglass with foam strips within the plies to add stiffness. Aluminum angles with slots were then riveted to the outer edges. The slots were to accommodate Velcro straps that would secure the sides to the floor. Also at four points are loops to anchor a net to secure the contents. Small aluminum panels are riveted to the floor on each side to prevent the sack contents from interfering with the flaperon control horns.

On my first Model IV, I was never comfortable with the shoulder harness attachment points. To keep the right harness on my shoulder, I made a strap that held the right and left straps together when I flew. Modifying that original design became a major focus as I followed the lead of some friends who were modifying the hat rack area during Model IV builds. One of them simply cut out the bracing in the Hat Rack area behind the seats for easier access to the baggage area. My choice was to cut it out as well, but then replacing it with the bracing design found in the skylight area between the wing spar carry through tubes. For the shoulder harness attachments, tabs were welded exactly between the shoulders of both passenger and pilot, then steel tubes were welded between those points and the corners at the aft edges of the turtle deck for strength.

HighWing

01-19-2017, 11:01 PM

Post Number 8 Engine Mount

When I did the W/B on my first.IV I found that I was forced to plackard my baggage capacity at 25 lbs. max. This was because of what I had done to the tail airfoils and fairings. Some calculations suggested I could recoup that on the new airplane by moving the engine forward a couple of inches. That and the long held wish of having the ignition modules hard mounted to the firewall half of the engine mount and the oil tank in a better location pushed me to build my own mount. A ring mount that fit the rear of the engine was made first. Then with that mounted to the rear of the engine, the engine was positioned in front of the fuselage on an engine stand in the desired position, and once again, the gap was closed with a welded tube structure. It was found that Kitfox used no thrust offset so the engine was placed in line with the longitudinal access of the fuselage. To determine the thrust line, a photo was taken of a friend’s Model IV as near to the level of the thrust line as I could. Using horizontal and vertical lines available in the editing program, the image was rotated until the prop blades were perfectly vertical which gave the correct horizontal of the thrust line as related to the fuselage. Lines were drawn on the photo to calculates dimensions from known landmarks.

The rubber isolators were made of a two part Urethane RTV cast in molds made of Delrin.

The only issue I discovered, was when fitting the cowl, it was found that the cowl contour drifted toward the centerline earlier than I thought and a modification was necessary for the cowl to clear the bottom of the oil tank. With my first Kitfox, I had noticed that the oil tank had several dents on the lower edge. It appeared that the stainless steel was soft, so tapping with a hammer created a dent that allowed for a quarter inch clearance at the bottom. I didn’t like the hammered look, so covered it with Micro and sanded it smooth. I didn’t like the look of the micro and this is the primary reason for the painted oil tank. The ignition coils fit as planned.

avidflyer

01-20-2017, 07:04 AM

Wow Lowell, you are a real craftsman! I would say that what you've shown us is a bit more than tinkering. :-) Maybe more like: an artist at work. JImChuk

jrevens

01-20-2017, 04:01 PM

That's all very cool, Lowell! Your mold for the engine mount isolators brought back memories of similar experimentation. Made a mold of aluminum to form urethane tailwheel tires for a Scott tailwheel, with the thought that they would last "forever" - or at least longer than the store-bought ones. The problem with the particular compound of urethane, soft enough to be similar to the factory made tires, was that it would take a set after sitting on the ground for awhile, creating a flat spot until it finally recovered. The "thump, thump, thump" when taxiing (especially in cold weather) drove me crazy. It was a fun project though.

HighWing

01-20-2017, 08:15 PM

Thanks, Jim.
Thinking about your post almost all day, lots of things came to mind. I think one thing I will claim and that is a level of perseverance. I always tell people to check my garbage can. Eventually the project will come out close enough.

HighWing

01-20-2017, 09:08 PM

The "thump, thump, thump" when taxiing (especially in cold weather) drove me crazy. It was a fun project though. Perfect example of the garbage can thing.

HighWing

01-20-2017, 09:19 PM

Post Number 9 Cowl Mods
It was obvious from the beginning that I would need to modify the cowl to fit the new engine location. For starters, the main cowl was moved as far forward as possible given the windshield requirements. Most of the lengthening was in the bubble cowl. A fiberglass extension was laid up on the aft edge after mounting the forward lip to the prop flange – lots of micro and sanding. Once that was done the final finish was started. I cut away the faired aft edge where it mated to the windshield and laid three or four layers of glass to get better fit against the windshield. Because I had put a piano hinge attachment top to bottom cowl on the Lancair IV I had helped with, that became the plan. First a tab and pocket was layed up on the forward edge of each side of the top and bottom main cowls. The hope here was to have the outside surfaces in that area consistently aligned since the piano hinge couldn’t extend to that area. The joggle for the camloc attachment was cut away and the edge sanded to parallel the piano hinge. Then after drilling a hole in both hinge halves every inch or so, the lower half of the piano hinge was attached to the lower cowl with clamps trying to place the hinge line at the top edge. Holes were drilled through the fiberglass and the hinge half was secured with clecoes. The hinge pin was replaced connecting the top and bottom halves and the top was lined up drilled and clecoed. I love fiberglass – easy to mess up and equally easy to fix. The hinge was placed as far forward as possible limited by the increasing curve near the forward edge. When all was good, the hinge contact surfaces were sanded, covered with hysol and riveted to their mating surfaces with solid flat head rivets. Final touches were to round the tailing edges of the lower main cowl to capture a bit of the door surround tube and the drilled steel fittings that were mounted on the door posts to capture the hinge pin on insertion to hold the joint snugly against the door post.
A trick I learned on the Lancair project. When mating two edges – upper and lower cowl for example - to correct a gap error, push some micro into the joint with a small putty knife smoothing it on the two mating surfaces, then take something resembling a dinner knife and run it down between the edges. Don’t worry about the bulge at the surface. After curing, sand the surface until smooth and pop it open. Minor careful sanding might be necessary at the inner edges.
The NACA ducts were suggested by similar ducts on the B-737 that provided air to the Auxiliary Power Unit. They were positioned just aft of the rear door and could be opened or closed in flight. I elected to cut the fiberglass sides and aft only leaving the forward uncut fiberglass as the hinge and using the original fiberglass skin. A piece of thin slightly oversized fiberglass was fixed to the doors as an overlap. A plug mold was made for the interior housing and a lever attached for opening and closing in flight – or more accurately before each flight depending on expected conditions. A cable control might be in its future.

GWright6970

01-21-2017, 08:08 PM

While I really love the detailed photos, I MUST ADD..... These photos do not do justice to Lowell's aircraft....it is honestly a total work of art!! You must see it for yourself to see the super attention to detail... An artist!

HighWing

01-22-2017, 11:03 PM

Thanks Grover. Your note got me thinking. Maybe it is the dental training. back in the day, very fine expectations were demanded in the school. If you could feel the junction between tooth and filling or crown - big write down.

Post Number 10 Door panels and quarter windows.

With the Model IV, the kit came from the factory with Lexan for the top portion and a fiberglass panel for the bottom of the doors. To accommodate the complex curve, these were connected across the middle with a molded fiberglass panel that fit well enough to result in a sort of scalloped appearance after riveting the parts to the frame. I never liked the look. This time, I found some aluminum H channel and decided to try it as a connecting joint between top and bottom panels. It needed to be bent to conform to the fore aft contour at the mid door bracing. To keep the aluminum from collapsing at the bend, thin aluminum strips were fit into the channels top and bottom until snug, then the bend location was marked and it was progressively bent by hand over a rounded piece of wood held in a vice. Once bent to shape, the inner flange at each end was cut away so the outer flange would lay flat against the door frame. Two holes were drilled on each end for riveting the channel to the door frame exactly between the two brace tubes. The H channel was clecoed half at a time and oversized Lexan sheets were laid in the H channels and trimmed to fit the curvature. When this was done, the holes for attaching the Lexan to the door frame were drilled and the sheets were clecoed to the frame. The doors were then mounted to the hinges and masking tape was used to mark the desired edge for cutting. I like the one piece look of the Acrylic doors and achieved that somewhat by painting the H channel and door frames black.
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I had seen door latches mounted in the traditional location with Allen Wrench sockets to accommodate a wrench as the door handle. I suppose these worked somewhat like a lock. I liked the streamline look and decided to try something like that. On the passenger side, it was decided to have only an internal handle and on the pilot side and an internal handle with the Allen Wrench device on the outside.
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The quarter windows had always seemed a challenge. In the old days, sections of fabric with the Lexan sewed into it were available as options. On my first IV, I decided to simply glue the triangle shaped Lexan in a fabric border and use that. It worked fine, but in time the Lexan started looking worn. This time the thought was to make the Lexan removable. The project started with a triangular aluminum frame that fit within the airframe tubing. Spacers and a flange where then riveted to the lower V sections to create a channel for the lower edges of the Lexan window “glass”. After covering was complete, the aluminum frames were glued to the inside if the fabric with Poly-tak and the fabric cut out. The Lexan was installed temporarily and four undersized holes were drilled through the aluminum and Lexan. Then the Lexan was removed and the holes in the aluminum were enlarged to accommodate #4 panhead screws. After paint, the Lexan was installed and the panhead screws were screwed into the Lexan.
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Mcgaero

01-23-2017, 03:42 AM

Thanks for sharing your Kitfox building journey Lowell, great to see the work behind a beautiful aircraft!

HighWing

01-23-2017, 11:00 AM

Thanks for sharing your Kitfox building journey Lowell, great to see the work behind a beautiful aircraft!

Thanks, Ben. Seeing your home is in Aus. forces me to mention some comments from my wife a couple of days ago. Retired from United Airlines after 44 years a flight attendant, she was straightening up a lot of accumulated stuff and commented, "I can't believe, I went to Sydney that many times". She loved your part of the world and took me there a couple of times to share her love. Though we never got that far south.

Christmas in Sydney:

Mcgaero

01-23-2017, 03:27 PM

Lowell, you've probably seen more of Sydney than I have! It is a nice place to spend some time thou. Your wife would be well traveled with a career of 44 years.
Keep up the posts and pics, its really valuable for the rest of us still building!

HighWing

01-23-2017, 10:52 PM

Attending a factory fly-in in Idaho while I was building 96KL, I noticed many of the Kitfoxes in attendance had duct tape over much of the surface of their oil coolers. This was in late summer. Too much cooling in summer definitelycaught my attention. The first decision was to use a smaller oil cooler than the one the factory supplied. Experience later suggested the cooling was still more than needed in flight and warm up times still seemed a bit long. A friend at the time was flying a Rans S-7 and he had an early oil thermostat setup on his airplane and it was complex and quite large. The solution for me was to try to make shutters for the oil cooler similar to what I had seen on the big-rigs as a kid. I first used one inch shutters, but then went to half inch because the air flow would move the larger shutters unless a push button cable control was used. I had to have them on 338S as well. I had used a riveted aluminum oil cooler mount on 96KL, but this time used a welded steel tube mount.
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In 2007 about fifteen minutes into a trip to the factory fly-in we had the oil pressure gauge drop to "0" PSI. We were in the foothills of the Sierra Nevada Mountains - Hilly and for the most part covered with oak trees. Primarily due to misjudging the slope - landed down hill - the landing destroyed the airplane but we made it out with mostly bruises. After almost exactly a year, the FAA contacted me with the determination that it was in fact a low oil pressure situation rather than a broken gauge or sender. To alleviate that uncertainty in the future, I located a pressure switch that provided contacts for two indicator lights, one provides power to a light when there is oil pressure and the other powers a light when there is no pressure. The two pressure senders were mounted on a manifold that was attached to the firewall side of the engine mount to eliminate vibration. With oil pressure in normal range, the indicator light is green showing a powered functioning system and with low oil pressure the light will flash red.
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jiott

01-24-2017, 10:37 AM

Lowell, how did you attach the cross shaft wires to the shutters? Hysol?

HighWing

01-24-2017, 06:05 PM

Jim,
Sorry for the late response. Attached is a picture of one of the vanes with pivot rod. I have a device that bends a shallow "J" shape on one edge of the vane. Then two crimps near each end are placed with a modified pair of small pliers to create a secure attachment with the rod, then using an irrigation syringe, a bead of HYSOL EA-9430 is placed between rod and curled edge up to ,but not including the crimps and the vane is rotated against the rod to coat the entire surface. I can add some pictures of the somewhat complex tooling if there is interest.
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Exciting day here. A local Avid guy came by to move his airplane from my hangar and he told me about a local Kitfox guy who had his airplane catch fire while using a preheater to prep for an early morning flight. No collateral damage and owner in good spirits despite a very likely totaled Model IV.

HighWing

01-25-2017, 11:14 PM

Post Number 12

Early on, one of the things I sometimes found a challenge was the throttle springs on the Bing Carburetors. Bump the button on the throttle and get an immediate surge of power. Doing a little experimenting, I found a way to put a counter acting spring behind the throttle. It is one reason I was never tempted by the newer split cables.
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In the early 80s I restored an antique car. When timing the engine it was typical to loosen a clamp on the distributor and rotating it a bit to find a smooth running spot, then adding a little throttle and doing it again to get a smooth running engine. With the early Kitfoxes having a bell crank dividing the throttle cables to the carburetors, it seemed logical that if a linkage could be divised to adjust one of the cables with a twist knob it would be easy to synchronize the carburetors by ear. Not so, at least in my ears. The throttle adjustor was a unit that was installed on the left arm of the bell crank with a round knob that was able to move the throttle cable on that side out or in a quarter inch relative to the bell crank.
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My understanding of the typical pneumatic system required removal of one end of the balance tube between the carburetors and attaching the differential vacuum gauges. Guys were complaining about having to pull the tube off the carburetor. To symplify that, a device was made that was epoxies to the separated cross tube with exchangeable middle sections. One with a simple pass through and one that separated right and left sides feeding separate 1/4" hose barbs.
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HighWing

01-30-2017, 12:18 PM

I started the video camera project in 2002. The first was operational in 2003, but there was continual effort to make it more friendly and reliable. The goal at first was to have a camera that would Pan, Tilt and Zoom. Then it was discovered that if setting it on infinity, the most used setting, every time I powered up the camera, the pulse of electricity would bump the focus setting closer in a bit resulting eventually in out of focus videos. Being able to switch from auto focus to manual focus eliminated that problem as most often while in the air everything was close to infinity. If on the ground, switching to auto focus would reset if for close in then focusing on something in the distance and back to manual reset it for flight. Then for more pleasant affects, auto to manual exposure was desirable as if in flight the nose pitched up a tad, the sky darkened and the ground darkened a lot. Then pitch down a bit and the ground was bright enough to see, but the sky was washed out. In bumpy air unless the camera was pretty much pointed to the ground, everything was in and out as far as brightness was concerned. Then the final touch was what I called the “Bug Wiper” that would remove the all too frequent bugs that found themselves on the front lexan lens protector. Finally, on the new Model IV, the “Focus” was on HD which was a major challenge as the image stabilizing systems really struggled with typical airplane prop vibration etc. To compensate for all these issues, the typical “Action Camera” is fixed focus, fixed aperture and wide angle. The first three project cameras recorded to MiniDV tapes. The last two, to memory cards.

To save a bit of space the pictures are in an album -

http://www.teamkitfox.com/Forums/album.php?albumid=478

A note on one detail. Controlling the camera was a major challenge. The solution was to hard wire the button contacts on the cordless remote to the control stick then removing the infrared LED and positioning it right in front of the camera. This way, I had full function of the Cordless Remote to control the typical camera functions - Camera Power on/off, Record on/off, Zoom in/out, .

These pictures are from the last of the two camera set-ups on N96KL. The HD project will be next.

HighWing

02-02-2017, 08:06 PM

Post Number 13. High Definition Video

The High Definition project

The big challenge began when I found that my Camera’s image stabilization function was totally inadequate to handle engine vibration and taxi motion. Its trip to a service center pronounced it perfect, so with some research the solution proved to be a Sony. The stabilization was markedly superior, though not picture perfect, it was better than most action cams. The first challenge was the video out to the monitor. No options but HDMI and the mini HDMI output was under the side LCD screen door which was on the tilt pivot bearing side. This required a 90° modification in the male mini plug. A couple of tries later, success. Inside that plug are two parallel layers, each with about 9 wires. Cutting the inside layer of wires with a very fine tooth Jewelers hack saw, bending it 90° - hopefully without damage to the bent wires and soldering in jumpers was the solution. Filling the gap with epoxy held everything solid with a final surface of white heat shrink tubing. This camera also had an input port that allowed a Varizoom controller to be used rather than using the cordless remote.
When building the airplane, the camera was in the plans from day one so the lift strut and fairings were modified for three hardpoints for the camera mount and a conduit provision for the cables and wires. The hard points were attached to two split tubes. The split tubes were fitted with cross tubes that accommodated bolts that allowed them to be clamped to the lift struts. An extra tube was welded on and threaded to accommodate three external bolts that served as the attachment points for the actual camera mount. These three protruded through the fairings and were the only things visible during the Airworthiness Inspection. The original plan was to try hydraulics to move the camera using Nylaflow tubing and small hydraulic cylinders attached to the joystick and camera mount. Bleeding these lines makes bleeding brakes a walk in the park. Once done, the movement was not crisp so that idea was abandoned. Cables were used, but this time all curves from the straight runs were led through rigidly formed lubricated Nylaflow tubes. The controls are a bit stiff, but it is still possible to pan while filming if done carefully
Having learned to weld between Kitfox one and two provided a much easier methodology for the fabrication of the actual mount. The fairings consist of five separate pieces. The bowl that fits around the camera. A trailing fairing behind the bowl which retains the shape required for the hydraulic cylinder needed for panning. A top aft fairing, a small mount fairing in front of the vertical attachment in front and the front fairing. A track on each side of the camera lens access slot provides for thin Lexan strips to be inserted to keep bugs and other debris from impacting the camera lens or pressurizing the camera bowl. Access to the camera is from the rear behind a door that can be removed with a coin. Several hours of video recording before the need to change memory cards reduced the need for toolless entry. The camera is mounted to a precisely fitted wedge shape that is secured within a mated shape on the pivoting mount. It is secured with a spring actuated clamp. A ring around the lens also adds to the stability. Three electrical connections provide camera power, HDMI out and the controller input.

Again due to the number of photos, they can be found in my Album
http://www.teamkitfox.com/Forums/album.php?albumid=479
A sample of the video from this set-up
https://www.youtube.com/watch?v=SQrIJYoe1HY&t=73s