(Editor's note: Nigel has been kind enough to allow the following information to be included in KROnline. While the topic information is more auto engine specific, the processes are most interesting and applicable to other areas of aircraft construction.)

INTRODUCTION

The stock manifold on the EA-81 has many drawbacks. It is restrictive to flow, and is heated by the coolant which reduces available normally aspirated power. It is heavy at 7 lbs, bulky, and has an awkward physical carburetor interface. A much improved manifold can be easily constructed from carbon fiber by the average builder. This article will attempt to describe how this may be accomplished. Carbon is used for its high modulus and low weight to give an acoustically solid structure. You will first make the head interface flanges from steel, and then design and construct the manifold itself. Although not complicated, construction is a multi-step process completed as a series of small evening tasks.

CYLINDER HEAD INTERFACE

The first parts to make are the cylinder head manifold and cooling interface adapter flanges. No these are not carbon and they are the toughest parts, but still easy for a homebuilder. There are a number of design options available. The simplest method requires basic tools but some brazing or welding is required which unfortunately is unavoidable.

The adapter plates will provide 1.5 in diameter stub tubes to couple with the carbon manifold. As the head ports are slightly smaller than this, the ports will require some slight enlargement. Using a 1 inch sanding drum on a drill gently open the head ports by grinding away aluminum on the inside face keeping the hole round. Try not to remove too much on the coolant passage side to leave as much clearance as possible for the coolant tubes to be added later. Check constantly with a piece of 1.5 inch stainless exhaust pipe until the ports are the correct size and match the pipe. Transition any ridges inside to make a smooth opening. There is a cast ridge running vertically into the port that will interfere with this process so grind it away at the opening area only and transition into the port. I'm not sure exactly what it does but all the experts say leave it in.

Now using a cut up file jacket, make a template of the bell shaped interface at the head port to include the 3 mounting bolt holes and surrounding flat gasket face area. Using the template fabricate two plates from .125 minimum stainless or 4130 steel. Drill the three mounting holes to 1/4 inch to later take 1/4 X 28 cap screws. Cut out the induction hole using a series of closely spaced drill holes and then a 1/4 round file unless you have access to a lathe, then turn them. Fit snugly to 1.5 by .035 inch stainless exhaust pipe. Mark and cut out the curved coolant slot using a drill and file. Fabricate two 1 inch long induction stub tubes from the 1.5 in pipe and temporarily fit them into the induction holes in the flange. Next make coolant outflow tubes from 3/4 in 4130 or stainless about 4 inches long but whatever will best fit your installation. Cut these tubes at about a 30 degree angle up from the horizontal to fit over the coolant holes in the flange. Now trial fit everything on the head ensuring all holes and ports properly align and the coolant tubes clear the bolt holes. When satisfied mark the locations and then braze or weld the pieces together. If you don't have OA welding equipment try a friend, or farm it out. You may try silver solder with a spitfire propane torch and Mapp gas but this has not been proved so be careful. The welding will probably warp the plate slightly so using an inverted belt sander, hold the plate nice and square against the belt and grind it flat. Rotate it occasionally to avoid uneven grinding. To prevent hose blow off, make a raised end on the coolant tubes by wrapping 2 turns of solid copper wire about 22 gauge near the end and solder. Now etch and paint with your favorite epoxy paint or enamel. The heads are metric so get some old bolts of the right thread and cut off ½ inch lengths of thread and screw these into the six mounting holes until flush or just slightly recessed with the head gasket face. First cut small slots in one end so you can turn then in with a screwdriver. Install these with JB Weld high temp epoxy available at any auto parts store. After cure drill and tap to 1/4 X 28. Purchase some 1/4 X 28 X 3/4 Allen head cap screws for mounting. Fabricate two gaskets from good quality gasket material to match your new adapter plates and bolt them on using Permatex gasket compound. The black rubber impregnated compressed paper stuff works best. Do not use cork or any other very soft material as it will squish out and leak when you torque the plates down. OK that was the worst part now on to the composite stuff.

MANIFOLD

You will make the inner core and fit it to the engine, then complete the various layups of carbon, then dissolve out the core, then fit attach tabs and the carb mountings, and finally finish the outside of your manifold. You first need to have the heads on with head gaskets and at least two bolts per side snugged up. This will a ensure proper fit of the manifold.

CORE

The core is made from fine grained builders insulation Styrofoam SM in three pieces, the plenum and two runners. Do not use the expanded bead popcorn foam as it is too rough. The design and shape of the plenum depends on your particular application and carburetor installation but basically it is a cavity which feeds the two runners. It serves as a capacitor or storage tank if you like, to help even the flow through the carb caused by the vacuum pulses. Mine is a down draft 2 barrel mounted on top of a 7 X 4.5 X 2 in plenum. For low profile applications a side draft carb could be used so design your plenum accordingly. Try hard to keep it symmetrical and watch out for the steering effect of the throttle plate(s) which tend to direct raw fuel to one side at part throttle. This will cause uneven mixture and all the associated headaches of roughness, burnt valves ad nauseam. My throttle plates open fore and aft so it remains symmetrical. Throttle plate symmetry is very important.

Cut your plenum core with a band saw or hack saw. Sit it on top of your engine in exactly the position you want it. Shim it up underneath to give at least 3/8 inch clearance from the block to allow for its eventual thickness and some running clearance. Now plan your runner shapes to provide a gentle curve from the plenum though a 90 degree down turn to mate with the top of the stub tubes on your head adapters. Make them by cutting foam out in two dimensions with a slightly tapered square cross section. In other words they are bigger at the plenum than at the heads. This keeps the velocity lower in the middle but provides more mass to help push the new charge in. Now trial fit the runners to the plenum and adjust as needed until you are happy. Use a sanding block to trim fit everything. Glue the runners to the plenum with a dob of 5 min epoxy or hot glue in the center of the joint not the edges because its hard to sand. Then re fit everything and push the runners gently onto the stub tubes to leave a slight impression sanding mark. Now start to shape the core by sanding the corners to a nice radius and working your way down the runners. Leave them basically square at the plenum and transition to perfectly round at the ends where they meet the stubs. They should be the same the inner diameter of the stubs seen by the impression marks that you made earlier. Foam seems to sand easier in one direction only. Use light pressure, take your time and trial fit regularly to check progress. The core will be a little rough due to the grain of the foam, this is OK. Any chunks that get torn out need to be filled with wax or something that wont stick to epoxy. It will not take long however to get a perfect Styrofoam core matched exactly to your application.

STICKY STUFF

The manifold is made of three plies of 282 2.7 oz bi-directional carbon reinforced with extra plies at the plenum. The preferred laminating resin is PTMW Aeropoxy or Epolite 2184 and 2410 hardener these have good high temperature properties and excellent peel strength. Any good laminating resin will probably do however but I would avoid 2427 as it has some nasty tendencies not to bond to itself even when properly sanded. I cant understand why people build high stress aeroplane joints with this stuff, its bad news and there are many better products available. To avoid a mess and bumpy overlaps the layups pretty much have to be done in stages with a cure in between. Start with the plenum top or bottom and lay on 2 plies of carbon with the weave at 45 degrees to the long axis. Lap about 1 inch onto the base of the runners and fully up the sides of the plenum flush with the other side. Use gloves and conform it with your hands. Carbon is very stiff initially and takes about 1 to 2 minutes for the resin to soften it, then it conforms just fine. Now do the runners with 1 ply and overlap onto the plenum by ½ to 1 inch. Wrap the small ends around the core best you can and allow an overhang which will be trimmed later. While your all sticky layup some mount tab construction material on saran or plastic sheet about 4 inches square 2 or 3 plies of carbon or glass. After cure transition the edges with a hard block and 40 grit sanding belt cut up or paper ensuring you don't damage the exposed core. Then do the same layup above to the other side overlapping the first layup on the sides of the plenum and runners. Use wet resin rich layups, shiny bit not dripping pin holes will leak air. When cured it will be much easier to handle so transition sand all the edges and do it all over again trying to move your overlaps slightly to avoid a big bump. When you are finished you should have 3 plies on the runners overlapped on their sides to 6 plies and 6 plies on the top, bottom and sides of the plenum. If you are mounting your carb to the plenum add a 3 or 4 ply pad over the mount point for added strength and to allow for sanding flat. When cured have a last look and if you are satisfied then place in your oven pre heated to 150 deg F and let soak for 30 min then gently raise the oven to 180 F and soak for another 30 minutes. This will raise the creep temp of the epoxy to about 250F.

Now trim the head ends of the runners flush with the foam core. Locate and cut out your carb inlet hole(s) with a dremel and dental burr or hole saw. Take a chisel and dig out much foam as you can reach from all openings. Dissolve out the rest with MEK or lacquer thinner. Gasoline is not recommended it turns the foam into a thick goo which won't completely dissolve and makes a real mess. Pour it full of boiling water with a little dish soap to remove any wax if you used it. Now slosh the inside with epoxy thinned out with a little MEK or alcohol, let drain and cure. This should make the inside nice and smooth. Repeat if necessary but a slightly rough plenum area helps vaporize and mix the fuel. The runner ends at the heads need to be very smooth this is the point of highest velocity, so sand the inside curves best you can with small strips of paper on your finger.

Mounting tabs(s) are next. Mount your nearly finished work of art on the engine and locate where you wish to secure it. Mine has one tab only on the rear which ties into the inner of two bolts on the cover plate on the former oil filler neck which is long gone. I fill my oil through a small fitting I made on a rocker cover breather pipe. Use the construction piece you laid up earlier and cut it into a tab about 1.5 inch at the junction of the plenum and tapered to about 3/4 inch at the bolt. Tack it in place with a dob of 5 min. When set make a flox fillet both sides at the junction and layup 2 plies carbon both sides overlapping onto the plenum. Cure, trim and drill out the bolt hole.

Block sand the carb mount pad until flat then drill the holes to mount your carb. Install AN-3 bolts from the inside up through the holes to make studs. Rough up the inside of the bolt heads and coat them with JB Weld to hold them in. If your carb has big mount holes mine does make some spacers from aluminum pipe or whatever to make a nice fit to the AN-3s. Add a vacuum port if you like made from small pipe Drill a corresponding hole somewhere in the plenum and secure it with JB Weld epoxy. OK almost done.

FINAL FINISHING

To make your new manifold a true work of art it needs a nice finish. Final wet sand all bumps until presentable, then paint on a thinned coat of epoxy and let cure for a few hours until a firm tacky then bake at 180F until cured. This will fill most of the weave and look pretty good, but for a really nice look, wet sand it again and apply another epoxy coat as before. I took mine one step further and sanded it with 320 then sprayed on a clear coat of Dupont Centarus clear coat. It looks like a mirror but this wont give you any more power.

MOUNTING

The transition to the stubs is made with a 2 inch length of 1.5 in ID rad hose and worm clamps, just like Lycont do it. The carbon should just touch the top of the stubs so there is no heat transfer and the manifold will run much colder than ambient due to the latent heat of vaporization of the gas. The worst case is after a 5 minute shutdown and re-start where the manifold gets heat soaked from the engine, but it wont get soft or collapse and once running will rapidly cool. Good luck and good flying..

I finally got around to getting enough photos digitized that I could produce an article for KRONLINE. Here Goes.

I decided to build my own "top end" that is all of the structure above the "boat" was built up from scratch. One of the problems I had early on was deciding how everything would fit together. I wanted the forward deck to be removable, but this meant much more work than just glassing the deck in place. To be sure I came up with a good attachment scheme, I decided I needed to have my instrument panel done to look at various attachment methods.

STEP 1 POSTERBOARD

I actually had fabricated everything out of cardboard prior to doing any foam and glass work, so I began by taking some sheets of white poster board from K-mart, and cutting them into a shape that would approximate the layout of both the forward and aft decks.

Then I would sit in the boat, with a cardboard mockup of the cowling and try to make the best tradeoff between panel space, and over the nose view. I used some other KR photos and looked closely at the KR-2 video I had to see what types of range in panel size I had.

Mine came out approximately in the midrange as far as height.

I cut out several instrument squares using a students compass and ruler. The Aircraft Spruce catalog has all the instrument panel dimensions, and I used these for a guide. By placing a series of vertical and horizontal guidelines on the poster board, I could mix and match instruments and get a good layout before going to the next step.

I used masking tape on the back of the instrument cutouts so I could move them around and try different placements. I also cut out some 2"x 7" and 2"x 8" radio stack cut outs as well.

To insure symmetry, you can fold the posterboard along the horizontal centerline, and trim it with scissors if you have to re-size it.

STEP 2 MASONITE

A local hardware store sold masonite in 2'x4' pre cut sizes, which worked out well as I had sold my truck. I was able to fit these into the back seat of the car. The posterboard was used as a template, and the rough outline was cut. Then it was easy to sit in the boat and check things out for size.

I trimmed the masonite down twice as during the cockpit trials, I found that the louder I made the airplane noises, the larger the panel looked. After cutting the masonite, I then went pack to the posterboard to re-shuffle the instruments in the panel.

STEPS 3-129

I don't have any photos of the forward deck build-up process so that will be left for another article. Suffice it to say that between steps 3 and 129 the panel size has become fixed and it is time to cut holes to check the clearance for the instruments themselves.

STEP 130 CUTTING MASONITE

This is a good practice step, as you find out if you have spaced everything correctly. I used a flycutter to cut holes in the masonite. Cut the holes small, then you can file them out to the appropriate size. I happened to have several junk instruments I purchased and have been given which allowed trial fits of just about everything except avionics.

If you are going to build your own fuel tank, make sure to leave room for avionics and if you ever plan to get an artificial horizon, the mil-surplus old stuff I have is deep.

STEP 131 CUTTING ALUMINUM

I had considered making my panel from wood, but my father who does a lot of woodworking suggested veneers, when I was having trouble finding hardwood in the correct dimensions for my panel. So I decided to cut the basic panel out of Aluminum.

Although I was able to find a local supplier for my firewall stainless steel, I decided to buy my aluminum panel material from Wicks. I have enough to do 1 and ½ more panels, so if anyone wants to make me a deal. Let me know.

Figure 1 Shows the posterboard, the masonite & the finished panel. Note that the oak veneer does not have all the holes cut at this time.

Flycutting the instrument holes was an experience. Not as bad as I expected. I have a small benchtop drill press which has paid for itself many times over during the project. I shelled out megabucks for a Unibit drill to do the intermediate holes for fuses etc. I wonder if I will ever get my money out of that?

STEP 132 DRESSING UP THE PANEL

You can dress up the aluminum panel, paint it, or do like I did, choose a veneer. The veneer I wanted was a beautiful burled Walnut, but at $380 for the veneer, I decided to go with something I could obtain locally. I purchased some Oak veneer for $20-30 and I also have some remaining if someone is interested.

I attached the veneer to the aluminum using Hexel structural adhesive. This stuff glues tools to particleboard, so I figured it would work equally as well on two items wanted to stick together. So far it hasn't let me down.

I

KRNET: Well, as most of you know, our beloved KRNET has a new parent and a new home. Ross Youngblood has agreed to take over the nurturing duties. We all owe a huge thank you to Mike Graves for fathering KRNET. When Mike first started looking at KRs, he was looking for an alternative to the RV family. He liked RVs, just not the price to complete one. The KR caught his eye. He then starting seeking information on the KRs. As you all know, there was little to be found. Thus the creation of KRNET. Mikes persistence paid off. We now have a fine forum for real time communication that allows builders to find answers to their questions AND find questions they didn't know they even had! Thank you Mike. We wish you well with building your new home and your new marriage.

Ross has agreed to assume the duties and operations of KRNET. I asked Ross to tell us about himself. He sent the following:

"I started my KR project in 1988 as diversion therapy from work. It was effective, but I changed jobs anyway, and got so busy that the project slowed in 1989. I picked up a few years ago, and it now looks like I may actually finish. My inspiration for newsletter submissions was Monte Miller, I liked his articles so much in the old newsletter that I decided to contribute some of my own.

There are several areas in the KR-2 plans set where we are left to "fill in" the blanks so to speak. I find that photographs of others projects help a lot to provide an anchor for these items that have several possible solutions. Hopefully I can help out by revealing both my good and bad decisions in my construction phase."

Ross failed to mention he likes people. This is a needed side of character if he hopes to keep what hair he has left. We KRNETters can be brutal at time. We all extend a warm welcome to Ross. He is doing the grunt work, toiling behind the scenes to help keep the system running. Thank you so much Ross.

Regarding the majordomo krnet mailing list, Ross wrote.

1) It's free.

2) Here's how to join:

Instructions:

To subscribe to the KRNET mailing list send an email to: majordomo@teleport.com with the following CONTENTS:

subscribe krnet-l

end

FULLNAME

EMAIL ADDRESS

NOTES:

"Please include your full name and email address after the end line. Working with Mike, we found that krnet-l has to be lower case. If you don't send your full name, I will email you back asking for it, this is extra work for me."

If you have tried to become a member, and have had problems, drop me a line rossy@teleport.com, and I will fix it (its my new job).

Your messages to krnet-l will not be posted to the list unless you are a member.

KR VIDEO: Video Bob is working hard on the editing duties as this is written. The Video should be ready before long. We will review it in KROnline as soon as it is done. Given the fact that Bob spent all of his time over two days behind his video camera, I know there will be a tremendous amount of good footage. I don't envy his task of trying to pare it down to a reasonable length video. Stay tuned…

CONSTRUCTION VIDEOS: We are looking to create some KR Construction videos. Anyone interested in helping should Email me direct.

BEARING HELP: KROnline needs a volunteer to write an article about Oilite bearings. They were a topic of conversation recently on KRNET, however, I don't feel the issue was covered as well as it should be. I have some ideas, but don't have the time to write it and put the newsletter together. If one of you fine readers would be so kind as to help me, I'll share with you what little I know that should get you started. Email me direct.

INSURANCE INFORMATION: Yes, KROnline needs a volunteer to write an article on their experiences in regards to insuring the KR. Email me direct.

ELECTRICAL SYSTEM: At first glance, this gadget may appear expensive…but look closer. A truly compact and complete electrical system for your airplane. For sure it cost less than the sum of the elements it replaces.

You can download all of the data about it by going to: http://www.controlvision.com/page20.htm

Price is listed at $249. The information on their web site is very complete. Be sure to take a look. This is a neat solution to a problem most of us face.

TAIL WHEEL SPRING(S): Mike Stearns wrote a note in regards to tail wheel springs:

"I used a standard RR tail wheel...BUT...based on

Roy Marsh's recommendation, I doubled up the tail

wheel spring. This should help compensate for the

longer tail moment of the 2S and the greater potential

resulting downward force on the tail wheel when my

landings are less than greasers.

NEW VW BOARD: There is a new VW Engine board that has just stated up this month. Still very new with only about 40-50 people on it, but I suspect it will grow as it is discovered. Ron Kimball has taken on the task of running this board. Postings so far have been good.

To get on the board mailing list, Email to: vw-request@toast.ml.org

Text should say:

subscribe

If you have problems, Email Ron direct at: ron@toast.ml.org

ELECTRIC ELEVATOR TRIM: Mike Stearns recently wrote:

A couple of you asked about the MAC trim. I paid $159 for the whole works which included the wiring, an electric panel switch and a position guage. Mine is mounted in the elevator itself

against the spar. It only weighs a couple of ounces and should

not effect elevator balance (which is unbalanced anyway). The base of the unit itself became its own inspection plate. The rod

is about 4" long, beefy, and has absolutely no slop in it.

TURTLE DECK CONSTRUCTION UPDATE: If you haven't in a while, I would recommend a visit to Mike Mims web page: http://pw2.netcom.com/~mimsmand/photos.html He posted good photos and a drawing to explain how he built his turtle decks. Good food for thought. A refined version of his article in the September issue of KROnline.

BENDABLE FOAM?: This was recently the net in relation to Dragon Fly builders. Thought it would be of interest to KR builders:

The polyurethane foam that we have used for years manufactured by Clark is no longer available, since Clark has closed their doors. The General Plastics Manufacturing Company has purchased much of the Clark line and offers the foam products that we use. The sheet foam for the fuselage is a last-a-foam FR-6700 rigid polyurethane . The wrinkle that we have run into is that the scoring machine that General Plastics acquired from Clark needed some major work at some expense to be operational again. GP elected not to get the machine operational again. There is a bright spot in all of this and that is that GP offers a foam product that can be used in the compound curve areas . The product is last-a-foam FR-4300 thermoplastic foam. The foam is flexible enough to form cold, but with the addition of heat tighter bends can be made and the foam will hold its shape. Short of scoring your own foam the

FR-4300 is the product that we are recommending.

We will be working with Wicks and Aircraft Spruce to supply this product.

GENERAL PLASTICS MFG. CO. P.O. BOX 9097, TACOMA, WA. 98409 PHONE 206-473-5000

ANOTHER CHOICE IS A FOAM CALLED ESTER CORE MANUFACTURED BY DIVINICELL LOCATED IN DE SOTO, TEXAS. PHONE NUMBER 214-228-7600. ONE OF OUR BUILDERS IN FLORIDA HAS USED THIS PRODUCT FOR HIS FUSELAGE, SAID IT WORKED GREAT AT HALF THE COST.

Aeropoxy PR-2032 laminating resin is an approved substitute for Hexel Safe-T-Poxy. This product is available at Wicks Aircraft 1-800-221-9425 and Aircraft Spruce and Speciality 1-800-824-1930.

VW ENGINE ASSEMBLE TIP: If you put anything on your case mating surfaces, it has been suggested that Yamabond 4 semi-drying liquid gasket. Get it at your local motorcycle dealer, about $6 for a squeeze tube. If it works for pressurized 2-cycle cases, it's gotta work for us, and it does. Bruce Patten smeared some on his C-85 when he put it back together. The engine leaks everywhere else, but not around the case halves!

KR FLIGHT NOTE: Ed Janssen sent in the following on a friend, Dave Davis:

"Dave enjoys buying, doing minor repairs to an aircraft, fly them for a bit, and sell them in favor of another project. He has followed this same procedure with a Vari-EZE, a Taylor Monoplane and now the KR-2 and already has his eye on a Dragonfly if he sells the KR-2. I failed to mention that the Vdub is a Type IV, 19?? cc. He reports that it flys much greater than anticipated (he never flew a KR before, but the Monoplane experience helped, I'm sure). It was a beautiful evening and he said that after a little trimming, it easily flew hands off in the calm air. He's learning to fly it slower on approach (about 65 indicated) which is giving him better landings. He teased at a stall but didn't get it to break - airspeed showed 45mph. He only has about 5 hours and 5 landings on it since its cosmetic work. Forgot to ask him about TT. I'll try to get him to write a report."

LOW COST TOOLS: Ricky Pitman recently forwarded this information:

I am a builder of a KR-2. I don't know if anyone has mentioned this before, but there is a source of tools that are priced right. First I want to say that I have no financial interest in the company and that depending on the particular tools you purchase and the price that you pay you will either be pleased or displeased. The name of the company is Harbor Freight. They will send you a free catalog if you call them at 1-800-423-2567. If your order is over $50.00 they will ship for free in the 48 states. (After you have spent two or three hundred dollars with them they will send coupons for free shipping on any item). I purchased a band saw for $ 99.00, a table top 1" x 30" belt sander for $ 49.00, a 2-hp table saw for $ 89.00, a 5 speed drill press for $ 49.00, a 3.5 hp 12 gallon air compressor for $ 199.00, and an air stapler/bread driver kit for $ 89.00. The list goes on. These are not commercial grade pieces of equipment as the price reflects. But so far everything has worked well for me. I have completely outfitted my shop with their equipment for the cost of a good commercial grade air compressor and band saw. Working the wood with the proper tools is really a pleasure. This is not meant to be a commercial for their company, but maybe a way to cut the cost of constructing your aircraft, get it built right (the first time), and have more time working on the aircraft. Call the number, get the catalog, and be your own judge. Many items are covered by a lifetime warranty, and all are covered by a 90 day warranty.

Before you buy, be aware that the prices seem to change from catalog to catalog. If you buy something today, you will get a catalog the next week with the same item for ten dollars less ( or more sometimes ).