Maj. Woody's FeiBao F-4J Phantom
02-23-2010, 07:48 PM
#701
RE: Maj. Woody's FeiBao F-4J Phantom
Since I added the blocks to raise the servos off the wing skin, There was no room left for the servo mounting screw heads once the servo cover is in place. The solution is to cut a chamfer into the aluminum brackets. You can see that they are flush and will not be any concern for the cover. The screws holding the servos to the plywood blocks are #4 X 5/8. These screws not only go through the 3/16” plywood blocks but penetrate into the servo frame as well. This arrangement is ridiculously strong!!
02-23-2010, 07:53 PM
#702
RE: Maj. Woody's FeiBao F-4J Phantom
The servo cover came from the factory with slots already cut into them. The slot for the flap servo lined up perfectly but the slot for the aileron servo was way off. The dimensions and locations of the slots will vary depending on what servos you use and what type of servo arm is used. For this reason, the factory should leave this up to the modeler to cut. No big deal, I simply relocated the slot, filled in the potion that was precut, sanded and painted it to match.
02-23-2010, 08:03 PM
#703
RE: Maj. Woody's FeiBao F-4J Phantom
Next I made my aileron and flap linkages from Sullivan Stainless Steel 4-40 threaded rod, Sullivan clevis, 4-40 nuts and keepers. The clevis and nut is loctited in place on the servo side. The linkages are very short, strong and straight lined with no offset. The linkages were then painted and the throws set. Aileron throw is 1 ¼” each way as measured at the wingtip portion of the aileron and flap throw is fully proportional (on my slider switch) up to 55mm as measured at the fuse. I can get much more travel than that on both aileron and flap but this is my starting point. I will fine tune it after the maiden to suite my flying style.
02-28-2010, 11:25 AM
#706
RE: Maj. Woody's FeiBao F-4J Phantom
All exposed plywood edges were given an application of thin ca. This adds strength to the plywood. Next I mounted the retract. I used 6-32 blind nuts. Start by drilling a pilot hole with a locating tool. Then take your time and work your way up the range of drill bits till you have the proper size for the blind nut. This seems like a lot of work but you will be rewarded with a perfectly centered hole. In fact since I have chamfered the retract unit (need clearance for the door) and am using tapered screws, it is a must or the screws wont seat properly. Go slow so you dont drill through your wing!
02-28-2010, 11:32 AM
#707
RE: Maj. Woody's FeiBao F-4J Phantom
The next order of business is to mount the main gear door. A plywood standoff must be made. Start with a piece of ¼” plywood and tapper not only length wise but width wise as well. This will be necessary for proper door fitment when closed. The block is then glued to the door. You can now drill and tap the landing gear for the 2-56” mounting screws.
02-28-2010, 11:42 AM
#708
RE: Maj. Woody's FeiBao F-4J Phantom
There are 3 doors total for the main gear. One is mounted to the landing gear strut. Another is operated by an air cylinder and the last via mechanical linkage. Here is how I made the mechanical linkage. Start with an offset door hinge and trim it down to accept a ball link. I used the new Tamjets door hinge in this case since it is the smallest in my assortment. After locating the correct position on the door, you can CA and screw this in place. Disassemble the landing gear strut in preparation for drilling and tapping the strut for the ball link. Using a drill press and vise is the only way to go here. Once complete, the two ball links are connected with ball end connectors and 2-56 threaded rod. Tune the length of this linkage to get a good tight sealing door when closed.
02-28-2010, 11:50 AM
#710
RE: Maj. Woody's FeiBao F-4J Phantom
The landing gear is now permanently mounted. Be sure to use loctite on all retract mounting screws and retract screws. The retracts were previously disassemble, lubed and leak tested prior to installation. I have covered that procedure before so I did not include it this time. Air lines are routed and quick disconnects were installed.
03-07-2010, 01:50 PM
#712
RE: Maj. Woody's FeiBao F-4J Phantom
I finally have both wings complete. Things are progressing slowly as I have not had a lot of time to build. I did not do any this weekend. The weather was too nice...sunny and 48 degrees.....outstanding for New York. The Cessna won the debate since I could not stand to be in the basement when it is that nice for flying out. I'll get back on the Phantom soon and I will be moving on to the tail section next.
03-11-2010, 07:17 PM
#716
RE: Maj. Woody's FeiBao F-4J Phantom
It was 60 degrees here today! I am having a real problem staying motivated to build. It has taken me about three days for the step shown below. I just can't stay focused with the good weather upon us. Well I forced myself into the basement after work today to finish the rudder installation.
The rudder servo is mounted in the bottom of the fin (the fin is removable) and there is an external pushrod to operate the rudder. First enlarge the opening to fit your servo. I used a JR DS9411……this produces 95 oz of tork @ 6 volts. You will need to create some mounting rails from hardwood. Be sure to anchor these rails to the spars and the fin skin to achieve the proper strength. Gluing the rails to the skin alone could result in flexing and ultimately rudder flutter. Mine arrangement is rock solid. Trim the fin TE as needed to achieve the proper rudder deflection without binding. Make a cutout in the fin for the servo arm then extend a line from there to the rudder in order to locate the location of the rudder control horn. The rudder control horn and rudder hinges are glued exactly as described above for the ailerons and flaps. I painted the fin TE flat white before gluing the rudder in place. The pushrod is also made the same as described earlier. I painted my linkages and servo arm to help conceal them. I set the rudder deflection at 2” left and 2” right as measured from the bottom of the rudder.
The rudder servo is mounted in the bottom of the fin (the fin is removable) and there is an external pushrod to operate the rudder. First enlarge the opening to fit your servo. I used a JR DS9411……this produces 95 oz of tork @ 6 volts. You will need to create some mounting rails from hardwood. Be sure to anchor these rails to the spars and the fin skin to achieve the proper strength. Gluing the rails to the skin alone could result in flexing and ultimately rudder flutter. Mine arrangement is rock solid. Trim the fin TE as needed to achieve the proper rudder deflection without binding. Make a cutout in the fin for the servo arm then extend a line from there to the rudder in order to locate the location of the rudder control horn. The rudder control horn and rudder hinges are glued exactly as described above for the ailerons and flaps. I painted the fin TE flat white before gluing the rudder in place. The pushrod is also made the same as described earlier. I painted my linkages and servo arm to help conceal them. I set the rudder deflection at 2” left and 2” right as measured from the bottom of the rudder.
03-14-2010, 07:58 PM
#721
RE: Maj. Woody's FeiBao F-4J Phantom
The stabilizer bearing plate is designed to be removable. The front of the plate is “keyed into a forward bulkhead and the rear is held in place with two bolts / blind nuts. While this arrangement will probably work well, I wanted a bit more security so I used epoxy to also glue the plate into position in addition to using the bolts. A few mods are in order since I still need to be able to service the rudder servo which is buried in the fin. The fin itself is removable but one of the bolts is under the bearing plate. Locate the position of the bolt by inserting a drill bit into the fin receiver bearing. A bit of red paint on the drill bit will locate the hole exactly. After drilling the hole, enlarge it in order to pass the bolt and washer through.
03-14-2010, 08:01 PM
#722
RE: Maj. Woody's FeiBao F-4J Phantom
In the stock configuration, the stab pivot bearing is held in position on the plate with bolts and stop nuts. Since my plate will be glued in permanently, I need to switch to blind nuts. I enlarged the hole in the pivot bearing to accept 6-32 bolts and blind nuts were glued into the bearing plate.
03-14-2010, 08:15 PM
#724
RE: Maj. Woody's FeiBao F-4J Phantom
The stab pivot bearing is composed of many parts that are bolted together. There was considerable slop in the shaft that passes through the bearings. This shaft was also a bit too short so tightening the end bolts and washers caused binding. I decided to machine a new shaft that fit the bearings snugly and also made it longer so tightening the bolts would not cause binding. Next I completely disassembled the rest of the unit. I cleaned and oiled the 4 ball bearings. I then reassembled the unit using RED Locktite on every bolt. Be sure you fully disassemble this unit and Locktite every bolt!! I also installed the bearings with Locktite 640 sleeve retainer to further reduce the slop in the assembly. There is still a slight amount of slop in the assembly but this is in the bearings themselves. The end result is about a 1/16” of wiggle at the tip of the stab. I checked with the General (Lewis Patton) who reports the same amount of wobble. He has dozens of flight on his F-4 with no problems resulting from the wobble.
03-14-2010, 08:19 PM
#725
RE: Maj. Woody's FeiBao F-4J Phantom
We all have our favorite techniques and preferences and these are mine. The supplied hardware is more than up to the job but those of you who know me, know how particular (ANAL) I am.
My stabilizer push rods are made from Hangar 9 Titanium turnbuckles, Dubro 4-40 Monster links, Sullivan golden 4-40 clevis / keepers and 4-40 nuts. Make two of these and be sure they are identical.
My stabilizer push rods are made from Hangar 9 Titanium turnbuckles, Dubro 4-40 Monster links, Sullivan golden 4-40 clevis / keepers and 4-40 nuts. Make two of these and be sure they are identical.