Tips, Tricks, and Modifications

Here is a summary of various things I learned during the course of constructing my airplane.

General | Chapter 4 | Chapter 5 | Chapter 6 | Chapter 7 | Chapter 8 | Chapter 9 | Chapter 10 | Chapter 11 | Chapter 13 | Chapter 16 | Chapter 18 | Chapter 20 | Chapter 24

General

Tip - Jig Table: Build a 12' table. 10' is too short. IT takes more room but it is worth it.
Tip - Applying slurry to foam: Go slow and be neat. This way I avoid the problems of getting slurry all over the back of the part I am working on. If I do get some slop I simply wipe it off and keep the plastic under the part clean as well.
Tip - Tracking Progress: As I progress through the construction of my plane I use a highlighter to mark what I have done. I use this as a sanity check too. When doing a specific task I read the plans a couple of times. After doing that task I take the highlighter and highlight the text of the task I just did. This allows me to confirm what I just did - before the epoxy dries, and it allows me to quickly see where I am in the plans.
Trick - Flox Fillets: I got this from John Slade. This really came in handy while doing all the taping at the end of chapter 6. Apply the flox to the corner to make a fillet. Don't try too hard to make it neat. Once all the flox is in place you can use a brush and some plain epoxy to smooth the flox into a nice fillet.

Chapter 4

Tip - Bulkhead cutouts: When cutting foam for the bulkheads you may wish to put off cutting the corners until chapter 6. In most cases you will need to trim the Instrument Panel, Seatback, and F-28 when you get to chapter 6. If you cut the bulkhead corners in chapter 4 you could find gaps later in chapter 6. Given all this it is easier to just put off all this until chapter 6 and make your corner cutouts to match your fuselage sides.
Trick - Instrument Panel Electrical Channels: I've read how some builders had a lot of trouble getting the two layers of BID to form the channel. Some built elaborate jigs to hold the glass in place. I found a simple solution. Lay the IP face down and add the 2 BID layup on the uderside of the two channels. Let it sit for an hour or two. Work on something else. Every now and again take a brush and coerce the glass around the corner. Eventually it begins to sit at an angle. Now lay some plastic over both channels and then put a board over the plastic. Make sure both are big enough to cover the full lenght of both channels. With the board in place the glass is held in position. When cure you just need to sand it a bit to get the correct height on the lip. Simple. In fact you could probably do this without waiting for it to stiffen up a bit.
Tip - F-22 doubler placement: When you put the F-22 doubler in place make sure each side is 3/8" from the side of F-22. This will be important during assembly in chapter 6.
Tip - Temporary Firewall: Don't worry about making the temporary firewall perfect. There are only a few important aspect of it. Mark the centerline. Mark the location of the longeron holes, and the hole for LWY. The rest can be rough cut.
Tip - Longeron cutouts in Firewall: Don't make any cutouts in the firewall except for the engine mount hardpoints. During chapter 6 you will make these cutouts in the temporary firewall first. Once everything fits properly you can transfer the location to the real firewall.

Chapter 5

Tip - Cutting Foam sides: When cutting the 3/8" foam for the sides, make the bottom edge a 1/4" too long from all the given dimensions. Later in the plans, when putting on the lower longeron, you will be asked to double check the dimensions and place the lower longeron in the proper place. Odds are if you cut the foam to the exact size the longeron will end up overhanging a bit. This will cause grief in chapter 7. Once the longeron is in place you can simply trim the foam flush with the longeron.
See my chaper 7, step 2 pictures to see what happens if you don't follow this suggestions - isn't hind sight great!
Tip - Gluing foam spacers in place: See the picture for the better way to put the foam in place on the fuselage jigs. I did mine the bad way and found my sides were a speck short when trimming at the end of chapter 5.
Tip - Glue foam sides first: Make the masonite jigs and cut the 3/8" foam to size and shape before attaching the jigs to the table. If you don't you won't have room to do so.
Tip - Attaching masonite to jigs: When you nail the masonite to the jigs don't go crazy with the hammer. When done you should be able to run a straight edge down the lenght, perpendicular to the top edge and there should be no gap. Think of all those bulkheads being put in place later. Remember that they have straight sides.
Trick - Clamping the lower longeron: Clamping the lower longeron can be tough. I made some small blocks with triangle cutouts. Worked great.
Tip - Electrical Channel Covers: Make the form 0.7" thick instead of 0.75". Otherwise you will have a bump when you sand the foam to match LWX, LWY, and the lower longeron (which are all 0.7" thick).
Tip - Foam Divots: When you remove the sides from the jigs you will most likely have a few divots. Remember how the sides get contoured in chapter 7. Don't worry about small divots in those areas.
Mod - Vance Atkinson Fuel Guages: I have ordered the guages and made the depression to fit them. I made the depression flat since the cant isn't necessary with these guages.

Chapter 6

Trick - Threaded Rod to squeeze sides: Threaded rod, a pair of matching nuts, and some big washers make it real easy to hold the boards against the fuselage sides when gluing in all the bulkheads.
Trick - 5" spacer for aft gear bulkhead: Instead of gluing a block in place on the fuselage side as a guide for the aft landing gear bulkhead, I glued a square of masonite to the temporary firewall. This square was 5" wide. This makes it easier to get the bulkhead straight and vertical.
Trick - 8" spacer for forward gear bulkhead: The plans say to glue 8" squares to the forward bulkhead. I chose to avoid this by making a standalone jig I could clamp to the bulkhead. The total lenght of the spacers and the base are still 8".
Tip - Putting the Bottom on: Follow the FAQ and put the bottom on in three steps. First - apply the BID to the bottom as directed. Follow this will peel ply where ever a tape will be applied. Allow this to cure. Second - flox the bottom into place. Wipe away excess flox so all is neat. Allow to cure. Third - Add all the tapes. Take as long as is needed. I found laying the fuselage on the side was the best for applying the tapes.
All the while ensure the fuselage is straight, level, and twist free overnight during each cure.

Chapter 7

Tip - Protect the NACA scoop: After sanding the NACA scoop foam to shape you should lay a piece of scrap foam or a board over the foam to protect it. Otherwise you may damage it while working on the joggle or making the holes for the aluminum mounts.
Mod - Antenna Placement: I am going to follow Jim Weir's antenna placement recommendations as outlined in the antenna builder's kit from RST. I put a marker beacon antenna along the bottom on the passenger side. I will not be putting a Loran ground plane in. I will put the VOR antenna in the wing (most likely).
Trick - Glass Around Landing Brake: After laying all the glass on the fuselage bottom I was having trouble getting the glass to lay down well in the recess around the landing brake. I decided to cut the glass, while it was wet, around the brake. This is normally cut in step 6 of chapter 9. This turned to work great.
Tip - Landing Gear Bulkhead Joggles: One word - avoid them like the plague! Find a way to build without them. Wayne Hicks found a way. Take a look at his.

Chapter 8

Mod - Shoulder Support: Like other builders, I will put a nutplate under the shoulder support for the canopy hinge. I will wait until chapter 18 to install the hinge which means I will wait until then to install the shoulder support.
I am also going to flox the aluminum nutplates under the shoulder support before installing the shoulder support instead of cutting a slot in the front and using a longer piece of aluminum that needs to be cut.
Mod - Shoulder Harness Spacing: My attach points are 11.5" center to center instead of 8.6". The original dimension was 11.5". Back in 1995 Nat made a mod down to 8.6" based on a report by Uli Wolter - the European Cozy designer. The concern was the possibility of the shoulder harnesses spreading enough to allow the person to slip through during some form of rapid decelaration (crash). Since I am using the recommened harness with an H-strap, there is no way for this to happen. Given all this I decided to go with the original 11.5" spacing. This has two advantages - 1) Better comfort - the closer spacing meant the straps rubbed on my neck, 2) No need to notch the headrests.
Tip - Plywood Seatbelt Reinforcement: Make sure the plywood seatbelt reinforcement in the forward left position lines up with the reinforcement for the outside step.
Trick - Transition Piece: After carving the transition piece from foam, cover it with electrical tape instead of box sealing tape. The electrical tape conforms perfectly to the shape. Simply spiral the tape around from one end to the other. After the layup cures, remove the foam anyway you want and then simply pull out the tape.

Chapter 9

Trick - Spot Facing Tool Replacement: Clark Canedy mentioned this on the mail list and I will whole heartedly agree. Don't buy the useless and expensive special spot facing tools used to make the 5/8" and 3/4" holes in the landing gear bulkheads. Instead go to your local hardware store (I got mine at True Value) and buy the Master Mechanic Bi-metal hole saws. The hole saws slide onto a 1/4" drill bit and lock into place with a set screw. For this chapter you will be using the 12" long drill bit so you can position the hole saw where needed. I also used a 7/8" hole saw to make the torque tube holes in the ears of the landing gear bulkheads.
Tip - UNI Strips for Strut: The plans call for 13 strips of 12" wide UNI cut at 30° angle to do the layups on the strut. The first set of 4 layers can be done with 8 strips. The second set of 4 layers done after building up the trailing edge can be done with 8 strips as well but they should be a little wider to cover the extended trailing edge.
Mod - Electric Landing Brake: I am using Wayne Lanza's electric landing brake actuator instead of the plans manual brake lever system. Keep in mind that Wayne changed the mounting braket in August or September of 2000. Most things in the mailing list archive talk about the old one. Measure carefully. Even the specs and instructions that come with the actuator are partially incorrect (At least when I bought mine in September 2000). Read my landing brake info in chapter 9 for more info.

Chapter 10

Tip - Spar Cap Tape: Order extra UNI tape. To be safe I would order an extra 12 yards. If you don't use it all it can be saved for the main spar and/or the wings.
Tip - Spar Cap Masking: As soon as you add the last layer of UNI tape, remove the masking tape and newspaper then add the peel ply. If you wait until the spar cap cures you may find the masking tape is hard to get off.

Chapter 11

Tip - Torque Tubes: Don't forget to make a left and a right torque tube when putting the NC-2s into place. They should be mirrors of each other.

Chapter 13

Mod - Electric Nose Lift: I have chosen to install Jack Wilhelmson's electric nose lift instead of the manual nose lift from Brock. When finished I will describe all the plans changes required to do this. There is actually very little changed other than different hardware.
Mod - Nose gear doors: Like a few other builders I have decided to make true nose gear doors. Mine will be very similar to Wayne Hick's but the details are being worked out on my own. More to come as this is completed.
Mod - Finish top of nose later: I am holding off the top of the nose until after the canopy has been installed so I can shape the whole top of the fuselage at once, including the canard cover.

Chapter 16

Tip - Marking parts: Mark everything! In the middle of each part I wrote (with a Sharpie) the name of the part (i.e. CS-105) plus the side it belonged to (L or R). At the end of each part I wrote the number of the part that that end went next to. In this picture the left most tube is CS-105. You can see 116 written on the end because this end of CS-105 was next to CS-116. The right most tube in the picture is CS-116. I wrote 105 on the end that mated with CS-105 (not counting the universal in between). You can even see (in the glare) 105 R written on the left end of the universal indicating that that end of the universal mated with CS-105 and belonged to the right set of controls. This all becomes most important when you start drilling holes because if you pick up the wrong end of a tube, the holes wont line up and you now have four combinations to try out. The last thing I did that is not in this picture is to mark mating ends with a line. Even if you have the two correct ends you still have two choices to line up the holes (rotate 180°). The mark lets you know the alignment. I just made all these notations after drilling each hole. This makes reassembly much easier later.

Chapter 18

Mod - Raising turtleback: I have raised the front of the turtleback about 1.75". The firewall end is per plans and the width is the same. This required a little CAD work to create new drawings for all jigs except the one at the firewall. I also created a new template for TB-1 since it must be taller too.
Tip - Reorder step 3: I added the drip rail prior to floxing the TB-1 bulkhead into place. Afterward I realized this probably made adding the drip rail much easier. If the bulkhead was in place I would have had a harder time marking and making the drip rail.
Trick - Making the Drip Rail: Gluing the drip rail foam into place takes some trickery. The foam needs to be forced into a compound curve. I found it worked best to cut the foam into 10" - 12" lengths and glue in each one at a time. I mixed the 5-minute epoxy, added it to the premarked foam (so I knew where to add the epoxy), waited a couple of minutes, and put the foam in place at about the 4 minute mark. I then only had to hold the foam for a minute to be sure the epoxy set. Using lengths of 10" - 12" allowed me to hold the whole piece in place with all my fingers. Any longer and it would have been very difficult to hold properly.

Chapter 20

Tip - Compare Cores: After you cut out all four core pieces, compare them side by side. Individually they may look fine but paired up you may find they aren't the same. I found this with my two lower winglets. I had mounted one end of one template off by 1". Looked fine by itself but when place next to the other, it was obvious one wasn't correct.

Chapter 24

Mod - Rear Seats: I made the rear seats different by attaching bulkheads similar to the front seats but attaching them to the seats instead of the fuselage. This way if I want to make room by removing the seats, the bulkheads won't be in the way.

Copyright © 2000-2004 Rick Maddy, All Rights Reserved