Maj. Woody's FeiBao F-4J Phantom
01-01-2009, 02:34 PM
#152
RE: Maj. Woody's FeiBao F-4J Phantom
Next disassemble and clean the retract cylinder, piston and shaft as well as all threads. Apply grease to the cylinder, O-Ring and also the threads and O-Rings where the cylinder screws together. You must carefully keep this aligned as you tighten the cap or you may pinch the O-Ring.
Next pressure test the cylinder. I check the pressure at 40 lbs and 100 lbs checking for leaks. The critical test is when the shaft is extended. You must firmly grasp the shaft and put a side load on it. If you loose any pressure here then you have to adjust the O-Ring. The fix is to thoroughly clean the piston and apply a few revolutions of Teflon tape. This effectively raises the O-Ring higher in the groove and thus applies more pressure to the cylinder wall. Re-grease everything and pressure test again. When satisfied, reassemble the retract using locktite on the bolts. Now, pressure test the fully assembled unit while attempting to apply a load to the trunion. None of my cylinders leaked but I did this for all three of my retracts just to be proactive and stay ahead of trouble.
Next pressure test the cylinder. I check the pressure at 40 lbs and 100 lbs checking for leaks. The critical test is when the shaft is extended. You must firmly grasp the shaft and put a side load on it. If you loose any pressure here then you have to adjust the O-Ring. The fix is to thoroughly clean the piston and apply a few revolutions of Teflon tape. This effectively raises the O-Ring higher in the groove and thus applies more pressure to the cylinder wall. Re-grease everything and pressure test again. When satisfied, reassemble the retract using locktite on the bolts. Now, pressure test the fully assembled unit while attempting to apply a load to the trunion. None of my cylinders leaked but I did this for all three of my retracts just to be proactive and stay ahead of trouble.
01-02-2009, 06:00 PM
#153
RE: Maj. Woody's FeiBao F-4J Phantom
Reassemble the wheels and tires. Next grease the brake O-Rings then tighten down the axle after applying locktite to the screw.
File a flat on the steering pin before inserting into the nose gear strut. Be sure to use locktite on the set screws. In addition to locktite on the trunion screw, I added some sleeve retainer (green locktite) to the servo mount stud before inserting this into the trunion. This should keep it from moving during at sharp jolt.
I think the gear looks great with the flat white paint!!
File a flat on the steering pin before inserting into the nose gear strut. Be sure to use locktite on the set screws. In addition to locktite on the trunion screw, I added some sleeve retainer (green locktite) to the servo mount stud before inserting this into the trunion. This should keep it from moving during at sharp jolt.
I think the gear looks great with the flat white paint!!
01-02-2009, 07:01 PM
#155
RE: Maj. Woody's FeiBao F-4J Phantom
Hi Bob.
I have not thought that far ahead yet. My plan at this point is to use two Futaba 9155's. These are 192 oz each. I pretty much use this servo on all my full flying stabs........Two on my F-18, two on the F-5E. I feel good about two servos but am not sure what the setup is going to be like on the 12FGA. Is there a matchbox type feature on that radio?
I have not thought that far ahead yet. My plan at this point is to use two Futaba 9155's. These are 192 oz each. I pretty much use this servo on all my full flying stabs........Two on my F-18, two on the F-5E. I feel good about two servos but am not sure what the setup is going to be like on the 12FGA. Is there a matchbox type feature on that radio?
01-02-2009, 08:31 PM
#156
RE: Maj. Woody's FeiBao F-4J Phantom
Well, you can adjust the center point and end points of two channels slaved to the same stick - that's basically all that a Matchbox really lets you do, so it should work.
I've been using the 8 channel receivers on most of my jets - cheaper than the 14 channel and for most of them 8 is enough channels. I was just thinking of one 8711 vs. two servos because its simpler and less prone to failure. Also, no matter how well you adjust the center and end points, the two servos are always fighting each other at least a little bit...
Bob
I've been using the 8 channel receivers on most of my jets - cheaper than the 14 channel and for most of them 8 is enough channels. I was just thinking of one 8711 vs. two servos because its simpler and less prone to failure. Also, no matter how well you adjust the center and end points, the two servos are always fighting each other at least a little bit...
Bob
01-03-2009, 04:48 PM
#157
RE: Maj. Woody's FeiBao F-4J Phantom
I started work on my cockpit today. This will probably take a couple of weeks to complete. Doing it now will allow me to progress with the build without stopping. At some point the cockpit will be needed and stopping to complete it later will cause me to loose momentum. I will post pics and details along the way.
01-03-2009, 06:15 PM
#158
RE: Maj. Woody's FeiBao F-4J Phantom
ORIGINAL: MaJ. Woody
I started work on my cockpit today. This will probably take a couple of weeks to complete. Doing it now will allow me to progress with the build without stopping. At some point the cockpit will be needed and stopping to complete it later will cause me to loose momentum. I will post pics and details along the way.
I started work on my cockpit today. This will probably take a couple of weeks to complete. Doing it now will allow me to progress with the build without stopping. At some point the cockpit will be needed and stopping to complete it later will cause me to loose momentum. I will post pics and details along the way.
I did mine first for the same reason!
I'm just finishing glassing the formers under the wing clamps as per Wagner's suggestion - it was a pain! Now I'm onto mounting the stab and servos so I can get the Details4scale chute in there. I'll post pictures of that when I get it done...Bob
01-04-2009, 01:51 PM
#160
RE: Maj. Woody's FeiBao F-4J Phantom
The kit comes with a fiberglass cockpit tub, glare shield and rear panel deck.
Trim the glare shield to fit into the desired position in the forward canopy area.
Wet sand the glare shield in preparation for painting. Next I constructed a HUD for the glare shield. Finally the entire assembly is sprayed flat black.
Trim the glare shield to fit into the desired position in the forward canopy area.
Wet sand the glare shield in preparation for painting. Next I constructed a HUD for the glare shield. Finally the entire assembly is sprayed flat black.
01-04-2009, 01:59 PM
#162
RE: Maj. Woody's FeiBao F-4J Phantom
Trim the cockpit tub as needed to fit inside the canopy framework. You will also determine the location of the forward instrument panel during this step. The tub will then be glued in this position when the cockpit is complete. The canopy and cockpit will then become one unit simplifying removal and installation on the flight line.
01-05-2009, 08:07 PM
#169
RE: Maj. Woody's FeiBao F-4J Phantom
They did work fine out of the box but.............everyone knows how anal I am about my stuff. I just had to rebuild them. One less thing to worry about. I strive for 100% reliability out of my equipment and go to great lengths to ensure it. I rarely have trouble at the field.
01-07-2009, 09:02 AM
#170
RE: Maj. Woody's FeiBao F-4J Phantom
Here are some pictures of my chute installation in my F-4. This is the Details4Scale unit for the Skymaster F-4. That airplane is apparently bigger than the FB F-4, so the unit has to be modified to fit. There is an air cylinder in front of the stab that pushes a piston down the tube to eject the chute. The pushrod for the chute runs between the stab linkages. Normally the door is hinged on the top corner to open up and to the side. However, I found that this put it right in the path of the inside aft stab tips and I was afraid that the door might get ripped off if you gave "up elevator" when the door was open. I decided to make the door open down which is non-scale, but safer as the stab can move to the ends of its throw and not hit the open door. The chute tube has to be shortened to fit into this airplane, but you need to leave it as long as possible so that the chute fits. You can see that it fits in there quite nicely. The door is held closed with two rear-earth magnet. A 65 PSI pulse of air into the cylinder ejects the chute completely...
Bob
Bob
01-07-2009, 09:26 AM
#171
RE: Maj. Woody's FeiBao F-4J Phantom
I thought I'd show my setup for adjusting the two servos that drive the stab.
I start by setting the servo arms on the servos so that they are as close as possible to the same position when the servo is at neutral. Then I adjust the two linkages so that they are the same length. After the two servos are installed, connect both to the Matchbox and attach only one of the linkages to the stab. Attach both servos to the Matchbox and reverse one of the servos. I designate one of the servos as the "master" (the non-reversed one that I initially connect to the stab) and stick to adjusting the other one (the slave) to match it.
I setup an input source for the Matchbox - you can use your receiver/transmitter for that, but I use an FMA Servo Lab as it can be set to hold various positions. Set the input source for the center position and use the Matchbox to adjust the slave servo's position so that the unattached linkage lines up with the hole in the horn. Then do the same for the ends of the travel. Don't forget to turn the Matchbox dial indicator back to "0" so that the settings are saved before you power it off... (I frequently forget to do that [&o] )
Next attach the linkage for the slave servo and insert an Amp meter (ammeter) between the battery and signal source (the receiver or Servo Lab). Turn on the signal source and set it for the center of travel again. Look at the ammeter and use the Matchbox to adjust the slave servo's position until you get minimum current draw on the ammeter. You can see from the pictures that I initially had about 350 mA current draw at the center position, but I was able to adjust that down to around 80 mA. The minimum current draw adjustment also *generally* coincides with the position where the servo buzzing is minimal, but using an ammeter is more accurate.
Finally, do the same for the servos at the ends of the travel (100 and 200 indicated on the Servo Lab or at 100% ATV on a receiver), and you are done. Don't forget to set the dial indicator back to "0" to save the settings on the Matchbox and label the servo extensions so that you can be sure that they get plugged into the right ports on the Matchbox if you need to disconnect them. Its also probably a good idea to label the Matchbox itself as the one for the stab...
Bob
I start by setting the servo arms on the servos so that they are as close as possible to the same position when the servo is at neutral. Then I adjust the two linkages so that they are the same length. After the two servos are installed, connect both to the Matchbox and attach only one of the linkages to the stab. Attach both servos to the Matchbox and reverse one of the servos. I designate one of the servos as the "master" (the non-reversed one that I initially connect to the stab) and stick to adjusting the other one (the slave) to match it.
I setup an input source for the Matchbox - you can use your receiver/transmitter for that, but I use an FMA Servo Lab as it can be set to hold various positions. Set the input source for the center position and use the Matchbox to adjust the slave servo's position so that the unattached linkage lines up with the hole in the horn. Then do the same for the ends of the travel. Don't forget to turn the Matchbox dial indicator back to "0" so that the settings are saved before you power it off... (I frequently forget to do that [&o] )
Next attach the linkage for the slave servo and insert an Amp meter (ammeter) between the battery and signal source (the receiver or Servo Lab). Turn on the signal source and set it for the center of travel again. Look at the ammeter and use the Matchbox to adjust the slave servo's position until you get minimum current draw on the ammeter. You can see from the pictures that I initially had about 350 mA current draw at the center position, but I was able to adjust that down to around 80 mA. The minimum current draw adjustment also *generally* coincides with the position where the servo buzzing is minimal, but using an ammeter is more accurate.
Finally, do the same for the servos at the ends of the travel (100 and 200 indicated on the Servo Lab or at 100% ATV on a receiver), and you are done. Don't forget to set the dial indicator back to "0" to save the settings on the Matchbox and label the servo extensions so that you can be sure that they get plugged into the right ports on the Matchbox if you need to disconnect them. Its also probably a good idea to label the Matchbox itself as the one for the stab...
Bob