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Jack Wilhelmson

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About Jack Wilhelmson

  • Rank
    Member
  • Birthday 06/27/1934

Flying Information

  • Flying Status
    Flying Cozy, Building MKIV

Personal Information

  • Location (Public)
    Mt. Pleasant SC
  • Occupation
    engineer(retired)

Project/Build Information

  • Plane
    Cozy Mark IV

Contact Methods

  • Website URL
    http://
  1. Some more comments that may be useful. I found that the hinges on the ailerons worked better with the hinge brackets if they are not reversed as called out in the plans. I also found that the hinges on the rudder worked better if they are reversed as called out in the plans. The method I used for mounting the hinges and brackets is as follows: 1. Trial fit the hinges and brackets on the aileron or rudder lip. The hinge pin should be directly under the edge. File off some of the front of the bracket to lower the hinge if needed. Check to make sure the brackets will fit on the aileron or rudder lip. If they hit the shear web and are held out too much you can file off the back of the bracket or cut out the shear web in the hinge area and reglass it. 2. Place the brackets on the hinge evenly spaced and with the small end of the bracket against the other half of the hinge. Mark the screw holes with a drill inserted through the plate nuts. Drill the hinge with a #10 drill. Fasten the brackets to the hinge brackets and make a final trial fit of the hinge bracket assemblies. The lip edge should be chamfered to .02-.03 thickness( in the hinge area only)fits against the chamfered edge and the hinge pin center line is in line with the edge. 3. Put some 3 mil plastic sheet between the hinge and the brackets and reassemble with the screws/ The 3 mil sheet shout be larger than the hinge by .5" on all sides. 4. Put a thin coat of flox on the lip in the hinge areas and clamp the hinge bracket assemblies to the lip. Adjust the position so that the Center line of the hinge pin is in line with the edge and below it about the radius of the hinge joint plus .03. Clamp and cure. 5. After cure, the problem is how to drill the rivet holes in line with the holes in the brackets. I did this by shinning a small fiber optic light on the holes in the brackets and drilling with a under size drill from the outside where the light spot could be seen through the composite glass lip. After getting the small drill though the glass in the aluminum hole then the hole can be realigned slightly and then drill out to the 1/8" dia. A penlight and a inspection mirror can also be used to shine a light directly behind the holes. 6. The holes then can be countersunk and pop rivets installed. be sure the counter sink is deep enough to allow one layer of bid over the rivet heads. 7. The brackets should covered with one layer of bid with flox filling the spaces in between the brackets and at the ends. Wax the screws and hinges and install them over the wet flox and bid and let cure. The aileron/rudder installed by putting some flox on the hinge and putting some foam rubber behind the hinge held in by pushing it down behind the hinge and clamping the rudder in place until cured. then the hinge can be permanently riveted to the rudder lip.
  2. There are many issues with using tractor airplane throttle quadrants and push pull controls on Cozy type airplanes. Usually the tractor airplane controls are very heavy and require much longer cables that reverse direction under the panel and then proceed back to the engine. The Brock throttle quadrant and cable setup is ideal from a weight and human engineering standpoint(This is my opnion based on flying many certified aircraft and my cozy for 16 years)but it leaves lots to be desired when it comes to installation, and performance. The first thing is that it is designed to be used with choke cable type cables. This means all the controls must have return springs which add to the force required to operate the controls and the controls do not operate well at all. By far the best type cables to use on all controls are the marine type push pull type with standard aircraft rod ends at the quadrant end and whatever is required at the other end. Having said this, what is needed is new version of the Brock type throttle quadrant that is designe to use the push pul cables with standard aircraft rod ends. it is possible to modify the Brock quadrant to use a push pull cable for the throttle only.(folks that use the Ellison throttle body or other fuel injection systems do this). This can be seen in the CSA newsletter.
  3. The brackets can be cut rectangular and trimed after bending if that is easier. Some other comments that may be useful. 1. I used AN3 hex hd bolts 3/8" long on the alerions. These can be accessed by using a 3/8" box end ignition wrench on the outboard hinge and a 3/8 " offset box end wrench on the center and inboad hinge. The rudders can use 10-32 pan hd screws 3/8" long. 2. on the ailerions the torque tube hole should opened up at the inboard end of the alierion so that the ailerion will have max upward deflection. This makes getting to the bolts easier. I will write up the procedure for mounting the brackets and hinges that I used later.
  4. The COSY(correct spelling is COZY) is fun to fly. It is a pilots airplane, a pocket rocket, poor man's fighter plane, and on top of all that is the easyest airplane to fly I have ever flown. The higher speed can be a problem until you get used to it but it is a economical traveling advantage. It has more usable room in it than any other airplane of similar weight and power. Yes you can carry four adults as long as they are not over standard FAA weight. The space is not less than a airline economy fare seat. I have flown many light aircraft and owned several, including a Piper Comanche for 15 years. Compared to a Cozy they all fly like Cleopatra's barge. The Comanche was a good IFR airplane but it was very demanding on landing and would not forgive any variation(+- 5mph)in airspeed on final and touch down. The Cozy will land at any speed above 60 Knots and be completely controllable on the ground as long as you have the runway length to accomadate the speed.
  5. The Cozy/LongEZ airplanes will not fly upside down. The reason they will not is that they do not have sufficient down(up when the airplane is upside down) elevator travel to hold the nose level with the horizon. So any attempt will end up in steep dive up side down. The wing is not a symetrical airfoil and therefore will require quite a high angle of attack to keep the airplane in level flight. The elevator has only 15 degrees of down travel and this is not enough. A axial roll can be done if the speed is high and the airplane is put into a good climb before executing it. Otherwise the nose will drop and split S will result with a very high speed recovery. Could spoil your day.
  6. I have a wood propeller on my Cozy (0320 160 hp) that has the best all around performance of any prop I have ever had. Turns up 2300 on the ground. Starts turning 2500 after about 200 foot roll and takes off in less than 900 -1000 ft at 1600 lbs. Cruise is 175 knots at 2700 rpm at 8000 ft.At low altitude it will go faster and overspeed the engine slightly. Also this propeller is the smoothest and most vibration free of any prop I ever had, when balanced with a static knife edge balancer. Now, the plot thickens. I recently removed it for some minor refinish and decided to document the pitch angles, thickness and airfoil shapes at 3" stations along the prop blades. I found that one blade has approx. two degrees more pitch angle at the tip and at all stations toward the center down to about 18" from the hub. I used a electronic angle indicator with resolution down to .1 degrees. This is a large error because the pitch angle at the tips is approx 20 degrees avg. The error is so great that I find it hard to believe that is a mistake. Could it be that this is the secret of this props outstanding range of performance?
  7. The drawing does show a flat. However, you are correct it is not really there or needed. It is product of the CAD modler that I used and I didn't want to take the time to wrestle with it.
  8. The aluminium hinges could be replaced with SS hinges of the same size but shorter. Especially the front one. Does anyone know of a source for these hinges in stainless steel. I have made hinges like this from carbon graphite\epoxy composite for my ailerions and rudder. I could also make much more robust carbon grafite hinges for the canopy. The hinge pins could be increased in diameter to offset the shorter length and the thickness of the hinge itself increased also. The process of making carbon graphite piano hinges is not to complicated but it requires a lot of time and some machine tools to make the molds and cut the slots. A friend of mine NICK Ugolini made a jig to cut the slots on his table saw. In any case making hinges is not the subject of this thread. If there is interested I could start one.
  9. Fellow builders: DD cooling is a subject that interest me also. When I first considereded it I felt as others do that it would be just naturally better. After several years of watching developments I have come the following conclusions: 1. DD cooling is better for the basic cooling job of cooling the cylinders. 2. DD cooling ends up being much more complex because the NACA scoop is still required to cool the oil cooler and provide air for the CARB or fuel injection. So you end up with two systems to provide air for instead of one. 3. The promise of less cooling drag is still only a theory and has not be proven. Logically the fact that a NACA scope under the airplane,even if it is smaller, and NACA scopes on top of the airplane increase the odds that cooling drag will not be reduced. 4. DD cooling causes overheating during extended taxi and during ground operation that has never been a problem with updraft cooling. 5. DD cooling causes the oil sump and carb. area to be heated if extensive baffling is not used below the engine to get the hor air out. This brings the question, is the baffling really simipler and easier? 6. DD cooling will probably cause the exahust pipe to run hotter. This will shoten their life. How much? 5. It appears that what we really need is a engine designed for updraft cooling. Intake on the bottom and exhaust on the top. I feel that the jury is still out on DD cooling. Any opnions that don't agree with mine are very welcome. I am still trying to take my own decsion on down draft cooling versus updraft cooling. Excuse any misspelled words please. No spell checker!
  10. Will clickbonds work? I think that the clickbonds will work for the ailerons if the method of attachment is reinforced with bid as Wayne described. However, it appears that you will not be able to access the fasteners on the rudders because the flange on the inside is in the way and the travel is limited by the hidden rudder horn(30 deg.). This can be solved by adding a 45 deg. wedge of foam covered with bid and flox under the clickbond. I have already done one wing and rudder using the nut plate bracket method and I have the parts made to do the other one, so I will use them, also this method uses tried and proven techniques and hardware(rivets, plate nuts, screws, etc). However, other builders might want to use the clickbond solution. Sharing information and methods between builders is the evolutionary process that makes these airplanes more and more valuable. The best way to make the brackets that are shown on the drawings is to make one out of thin alumium or heavy paper and then flatten it to get the flat pattern needed. Then make a piece of hard wood the dimension of the inside (.92) and bend the piece in a u shape over it. Clamp the bent piece with the piece of wood in it in a soft jawed vise at the correct angle and bend the ears down flat against the vise with a soft hammer. This worked OK for me.
  11. One of the appearance items that always bugged me about the canard airplanes, including my own, was the exposed screws and hinges on the ailerions and rudders. They posed a problem during finishing because they are in the way of sanding. My main concern was the apearance. So, when I built my wings for my new airplane I decided to devise a way to hide the hinges and screw heads. It turned out that the solution was not as hard as it might seem to be. If the hinge line is lowered below the skin surface by .1 inches, the cutout for the hinge can be eliminated. Since the ailerons only move upward 30 degrees this does not cause edge interference if the gap is .06 or more. The screw heads can be hidden if a small nut plate bracket is used such that the screw heads can be accessed from the underside of the aileron through the ailerion gap when the aileron is deflected upward. The nut plate bracket is made in a slanted hat section with the nut plate riveted to the top of the hat. The slant of the top of the hat is 30 degrees this gives clearance for the nut plate and screw. The wings or brim of the hat section is about .5 and is used to flush rivet the bracket to the top skin. The only critical part is to make sure that the brackets are placed so that a screw driver has a straight shot to the screw heads. The ailerons are not as easy to remove with this modification because the screws must be removed from under the wing looking up while holding the ailerion up. The smooth unbroken line of the wing and aileron is much more attactive and aerodynamic. The rudders also can use the same brackets. There is no change to the aileron cutouts in the wing or the reinfocement layups that hold the hinges. This means that a completed aircraft or assembly could be modified by adding the brackets and filling in the hinge cutouts. If there is a lot of interest in this mod I will add some drawings of the brackets and installation pictures to our website.
  12. John: I know that the "expert" you mentioned recomments this. I still disagree. There are several other minor reasons for not putting the starter solnoid on the engine side of the firewall and the battery on the other side. If a ammeter that is designed to read both inflow and outflow from the batery is used then the shunt for the ammeter, the main feed for the master solnoid, and the sensing wires for the ammeter will all have to penetrate the firewall or the alternator power lead will need to penetrate the firewall. These are all minor complications and proper fusing and protection can be provided with these realitive low current circuits. In any case, my question is, why should this be done, when it is easier and safer to place all this on the other side of the fire wall. Stuck starter solnoids are rare, however, they do occur, but they occurr during startng and not during flight. IF, the fat wires must run unfused through the firewall, then the usual rubber gromets are not adequate for protection because they tend to become brittle with age and split. The hole through the firewall should be insulated with a hard insulator bushing (nylon, Teflon or similar material.
  13. John: I looked at your firewall picture and honestly I can't understand the hookup at all. Could you send me the full schematic you are working from? Questions: 1. Why are the two master solonoids (normal and emergency) coils connected the the left and right ignition switchs? 2. It appears that the normal and emergency buses are direct wired together? Have you considered putting the emergency power battery in the nose to help the weight and balance? I assume you would not use the emergency battery for starting current except as a booster for the other battery. I think that I will consider doing this on my next airplane. The advantage is that the wiring to the front battery can be lighter wire because all the thngs the emergency battey needs to run (except the ignition and fuel pumps) are up front.
  14. I am posting on this subject to get it started and also to get some onions. Several builders have ask me this question about the type and connections of the starting relay and I have found that some "experts" are giving answers that I don't agree with. The first is that it is ok to route the starting current through the master power relay. I disagree with this because the starting current can exceed the relay rating. Also the staring current drain may be so high that the battery voltage drops below the hold in voltage of the master relay. In this case the master relay will drop out under high current and ARC the contacts. The starting relay should have it's own feed from the battery. The master relay feed should have a high current "fuse of last resort(50 amp)" in it's primary feed. The second is that it is ok to mount the battery on one side of the firewall and the staring relay on the other side. The starting relay should be very close to the battery and on the same side of the firewall with the battery. Never run a unfused primary lead through the firewall. It is ok to run the heavy wire from the starting relay through the firewall because it is only hot during starting.
  15. You can just add 40-50 F to the readings and you will be in the ball park. You can also make your own thermocouples. Buy thermocouple wire from Omega Engineering .50 a ft. for 25 ft. Silver solder the wires to a copper sparkplug gasket. J type is the most common for Cyl. head. K type for exhaust gas.

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