Building a Cozy MK IV Landing Gear And Landing Brake

Chapter 9

Landing gear, brakes and landing brake


Click on the pictures for a larger image.

Go get a cup of coffee, this is a huge chapter and will take a while.

I started this chapter by cutting out the landing brake from the bottom of the fuselage again (remember this was originally done in chapter 7 and was glassed over). I cut the required birch plywood for the reinforcements for where the hinge and the actuator cylinder will attach.








 I next with epoxied the aluminum blocks to the back side of the hinge plywood which will later be drilled and tapped for the 10-32 hinge screws. I installed the two plywood blocks in the appropriate places according to the plans. I made the recess with my router to make room for clearance for the fiberglass layers on the recess and the underside of the landing brake. I installed the plywood for the hinge and test fit everything. I checked to make sure that I have enough clearance between the landing brake and the bottom of the fuselage for the fiberglass that is about to be added. I removed the landing brake and fiber glassed the recess with the required layers of BID fiberglass.









Next I drilled and tapped the 10-32 holes through the blocks I epoxied earlier in place for the hinge screws and installed the landing brake. I once again checked for clearance for the fiberglass that will be added to the underside of the landing brake. Notice the hardware store screws, I dont have the "real" AN screws (the AN stands for Army Navy which is a military standard) yet and used these for temporary. My first moving part!








I installed 1" x 4"'s on the back of the landing brake to keep it flat untill I get it fiberglassed on the second side.









I then removed the landing brake and prepared it for fiber glassing on the underside.









I applied micro and then three layers of BID fiberglass with a 45 degree fiber orientation. After giving it a couple hours to partial setup I installed the landing break on the fuselage, closed it and weighted it down hoping it will stay flat. Keeping these flat seems to be a common challenge. After a couple of days I will remove the weights and see if I was successful.











I borrowed Wane Hicks idea on how to make the landing gear cover.
I started working on the landing gear cover by cutting a piece of Clarks foam to fit the opening tightly. With the foam in place I turned the fuselage over and glued some temporary foam blocks against the other side of the Clarks foam to help hold it in place. I then turned the fuselage over upside down and sanded the foam block to the shape of the bottom of the fuselage and the NACA scoop. Once I got that I took some clear box tape and taped the joint between the foam and the fuselage. This will allow me to make a lip in the fiberglass cover after I remove the part from the fuselage. I then applied micro and fiber glassed the landing gear cover with two layers of BID fiberglass.

















After the epoxy set up, I removed the landing gear cover from the fuselage and trimmed the extra fiberglass from the part. I then glued the cover to two 1" x 3" boards to keep the cover from warping. Next I took one of my filleting knifes and cut most of the extra foam off, and finished with sand paper until there was about 1/4" of foam left. I removed all of the foam where the fiberglass was over the box tape. The second side will get glassed after I have the landing gear in place. I also removed foam where needed to give the landing gear strut clearance.
















Today I did the fiberglass reinforcing that goes between the two landing gear bulkheads. This area gets built up quite a bit with many layers of fiberglass to take the impact of a bad landing. This was one of the most difficult layups yet, due to all of the angles and doing it with a single piece of cloth (but many layers). After fiberglassing I peel plied the edges to prevent the need for sanding.










At this point I removed the fuselage from the tripods and sat it on saw horses. There is a small delay in building while I prep our boat for sale. I am currently ordering the materials needed to complete this chapter.


Today (5/25/10) my landing gear struts came in for the main gear and the nose gear. I started preparing the main gear strut by sanding the glaze off of the strut with my belt sander. I did this with my Darth Vader outfit on due to not wanting to breathe the fiberglass and getting the dust on me (itchy). Next I ground down the "humps" that the plans called for. I then took the strut to the work bench and mounted on top of some 6" screws to prepare it for fiber glass. The first picture below shows what it looks like when it comes from FeatherLite (the manufacture). The second picture is the strut ready for fiber glassing.










Next I applied the 4 layers of fiberglass for torsion. I alternated the fiber orientation back and forth maintaining the 30 degrees fiber orientation per plans. I didn't worry about making a nice trailing egde because I am going to make strut fairings that will hide all of the trailing edge. Here is a picture of this.









The next step is to build the tabs that will hold the landing gear in the aircraft. I built a box per plans to fit the top of the landing gear strut. The box is temporarily bondoed to the strut and then covered by box tape (for release) in the areas that the fiberglass tabs will be built. The landing gear strut is then moved to the work bench and stood up on the box. The landing gear is checked for the correct angle and is corrected by shims. The box is then bondoed to the work bench and a couple of supports was added from the bench to the top of the strut to make it stable. I didn't get any pictures of this master piece, it was quite the contraption. Next you start the process of 230 pieces of fiberglass. Yes that is 230 pieces. Here it is with the box built on top of the strut to help build the tabs at the proper angle.









Here it is after the process of 230 pieces of fiberglass. The box was removed and the 1/4 in holes are drilled in the proper location and then you cut the tabs to be 3 inches wide with a 1 1/2 radius. Before you start this process, make sure you have plenty of jig saw blades. The fiberglass eats through them. Saws all worked much better.









Next you take the landing gear strut to the fuselage and install it for the first of many times. You take two 12 inch long 1/4 inch drill bits and slide them through the forward and rear landing gear bulkheads and through the holes you made in the landing gear strut tabs. I got lucky and everything lined up perfectly. Here is a picture of the landing gear strut in the fuselage.









Next I did all of the checks that the plans called for. I first slid two small strips of half inch plywood between the forward bulkhead and the landing gear strut pad to make the strut straight with the fuselage and to hold the back of the landing gear at the correct F.S. (F.S. = flight station which is a measurment taken in inches from the front of the fusalage). Then I found center on the fuselage and transferred the center line to the garage floor using a plumb bob. I laid a straight edge perpendicular to the fuselage centerline at 108.25 F.S. I then dropped the plumb bob down from the leading edge of the landing gear strut to check the angle of the landing gear strut. It checked correct. I put my straight edge across the top of the landing gear to check for level and it also checked correctly. I next checked that the landing gear strut is centered on the fuselage and it is. I spent about 4 hours doing these checks twice because it will be much harder to correct later.


I next intalled the MG 1s and the MG2s, these are plates that the main landing gear bolts will go through. The blue crap in the picture is bondo; they have you use it to temporarily hold the parts on to give you a chance to get the bolt through the center. The screws are hardware store screws, my AN bolts are not here yet.









Next I took my 5/8 inch and a 3/4 inch Ace Hardware hole saw, I would sugest a higher quality holesaw, and calibrated them to make the correct size holes.

Tonight I drilled the 3/4” holes through the landing gear tabs. After calibrating the hole saw the holes came out .005 of an inch too small, oops. I will open them to size with my rat tail file. I also started drilling out the 5/8" holes through the bulkheads and plates but my hole saw lost some teeth in the process so I had to stop until I find a dentist or get another hole saw. With a new hole saw (the last 5/8" hole saw in town) I carefully finished drilling the holes. I carefully opened the holes up to the finish size with a file. I then test fit the parts without the strut to check for alignment.









I then installed the spacer sleeve into the tabs on the landing gear and installed the landing gear into the fuselage.

My order of parts came in and the bolts that came to hold the MG 1's and MG 2's in were too short, they didn’t give me the minimum one thread through the nut. In my next order I ordered 16 MS24694-S64 bolts and they fit properly.

The alignment of the pins and bushings took some time but the pins slide in and out by hand smoothly. It took me three nights after work to get them to work like this but I got it. Once everything was lined up, I floxed the sleeve and bushings in place. After the flox set up, I removed the landing gear strut again. I cut some foam to fit under and aside the sleeve in the landing gear strut and applied two layers of BID fiberglass with the fibers at a 45 degree orientation. I then floxed the washers in place on the outside of the strut tabs, added flox to the edges of the washers to make a smooth transition to the tabs and applied two layers of BID fiberglass. I used some wire ties to help hold the fiberglass to the proper shape until the epoxy is set up. All that is left to do is to cut the excess fiberglass off and remove the peel ply and the landing gear attachment tabs will be complete. 










I next built the landing gear strut fairings. This is not discussed in the plans; however it looks like an easy way to gain some extra cruise speed. According to Wayne Hicks, you might gain up to 7-10 knots of airspeed. I won't go into detail on how I built the fairings because I followed Wayne Hicks website step by step, thanks Wayne.
Below is a picture of the foam blocks cut and the strut marked and numbered for the location of the individual blocks locations. I used pour foam to stick the blocks together, go fast when you work with pour foam because you only get about 15 seconds to work. I purchased one, two feet by four feet, two inches thick sheet of foam to make these fairings. The process of making the fairing is easy and fun, it took me about a day and a half to complete.









Below is a picture of the strut with the foam blocks installed and the foam partially sanded. I used the sanding block to the left side of the picture to sand the foam. After this you make a block shaped like the airfoil to finish shaping the foam.









I then applied two layers of BID fiberglass to one side of the strut/fairing. I applied peal ply to the trailing edge to prepare for the second layup tomorrow.

After the second layup I reinstalled the landing gear in the fuselage and trimmed the new fairings to fit the fuselage. This is what the completed landing gear strut looks like.









I then cleaned up the garage to get ready for the installation of the brakes and wheels (there was foam dust everywhere from making the fairings).

I will be installing Matco W51LXT wheel & brake kit with WHLAXLE1A axles. The Matco triple piston brakes are recommended over the stock Cleveland brakes because the Matcos have far better stopping power. This is what they look like.








I will next install the axles to the landing gear strut with (I hope) the proper toe in.

I first measured off for the proper location of the axles. Once I had that I took a speed clamp and clamped the axle in place. I rechecked the measurements again thinking I only get one shot at this and I have a lot of time and money in the landing gear strut at this point. The next day I checked everything one more time and then drilled the holes in the strut for the axles. I then made a template out of paper to cut a relief into the strut for clearance, so that the brake caliper will fit. The S fiberglass that the strut is made of is tough. I roughed it in with a saws all after burning up about 5 jigsaw blades. The saws all did both sides on one blade. I then finished the shape with a Dremal tool and a coarse sanding drum.
I cut two pieces of 1/2" OSB board about 3 inches by 5 inches. I put box tape on one side of the wood for a release. I then installed the three layers of BID fiber glass on the strut and then applied flox and clamped the OSB to the strut. I used a laser level to set the toe in before the flox set up.










While the epoxy was setting up I mounted one of the tires on the rim. Aircraft have split rims so mounting tires are easy, just be careful not to pinch the inner tube between the rim halves. If you partially inflate the inner tube (to the point where it takes it normal inflated shape) the inner tube seems to stay out of the way of the rim halves. If you have a hard time compressing the two rim halves close enough together to get the nuts started on the bolts that holds the rim halves together (as I did with my 6 ply tires), install the rim on the axle and compress the rim halves together with the axle nut. That worked great.
One of my flox pads didn’t come out flat so I sanded the old pad and I made a new flox pad for the axle to be mounted onto. I think my clamps were too tight and bent the board. If you only use one clamp per pad you won’t have that problem.

My second try at making the flox pad worked great with the correct toe in.

I then made two heat shields to protect the S glass landing gear strut from the heat generated by the brakes. Below is a picture of what the heat shields look like.









I assembled everything. I checked that the brake components have clearance from the heat shield and clearance from the landing gear strut. Below is what it looks like now. It has wheels!

The wheels are assembled with hardware store bolts now. They will be replaced with the proper AN bolts when the bolts come in Monday. The AN in AN bolts stand for army navy which is a military specification for bolts.
















Next I started cutting the landing gear cover to fit the opening in the fuselage. This will close up the opening where the landing gear is attached to the fuselage. Once I got it to fit the opening, I fiber glassed the second side with two layers of BID (bidirectional) fiberglass. After the layup cured, I trimmed the new fiberglass and fit the cover into the opening.
I next made a lip inside the opening to allow for an area to install the nut plates that will hold the cover in place. I drilled the screw holes and with help from my friend Kevin, we installed the nut plates. Without a rivet squeezer, it takes two people to install the rivets on this flange or one person with three hands.








Next I finished the landing gear bulkheads by closing the top of the bulkheads per plans. And finally, this completes this chapter. At completion of this chapter, the fuselage with everything included in this chapter plus the landing gear strut fairings, weighs 177 lbs. This chapter added 74 lbs. Below is what it looks like to this point. Now on to Chapter 10, construction of the canard. Chapter 9 is completed on Sunday, July 18, 2010.





 

If you have any questions, comments or concerns, feel free to email me @ Jfisher59@gci.net


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