RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Center Wing (cont)

Gear doors (cont)

pic 1:
I CA'ed the kit provided hinges to the door.
I did mine 1" in from each end.
The distance from the center of the hinge pin hole to the edge of the door is 3/16".
This location is easy to find since comparf has a small half round notch in the hinge which allows the door to open more (the notch matching the edge of the panels surface).

pic 2:
Some kit provide white tubing cut into 3/4" lengths and a kit provide hinge wire run between the two hinges to keep the white tubing aligned while epoxy was applied to the outer panel. The final hinge wire is cut 2 1/4" long and a 90 degree bend on one end.
Two notches 1/8" wide by 1/4" long was cut into the outer panel to make room for the hinge.

pic 3-5:
A dremel cut off wheel used to cut slots into the wing.
A rounded ended grinding bit was used to dress up the slot that was over a rib to fit the rounded white tubing.
Enough room was cut so the white tubing and wire hinge can fit into the slot.

pic 6-7:
Door in closed position.
So far, four #2 screws were used to hold the right side of the back outer panel to the wing.
The two notches in the outer panel for the hinges can easily be seen in these pictures.

pic 8-9:
The door opens easily and more than enough in the open position.
Later, I'll use some #0 screws and epoxy the hinge to the door.
I like this procedure of the doors attached to the back removable panel: it makes it pretty easy to align/epoxy the hinges to the outer panel and maintenance will be a lot easier, plus all that CF will make everything very strong and there is a natural lip all the way around the wheel well to make the doors flush to the wing.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Center wing (cont)

Gear doors (cont)

pic 1/2:
The hinges CA'ed to the inside door.
The hinges with the extra hole go towards the front for connecting the air cylinders.

pic 3:
Full door/panel assembly.
Since the white tubing stress will be towards the panel, not a lot of epoxy is needed to hold them in place.
The doors, however, will get some stress so screws will also be used to hold the hinges to the doors.

pic 4:
Notches cut into the wing to make room for the white tubing/pins and one end of the hinge.
These notches will also help to hold the white tubing in place.
Since I have a 1/8" lip around the wing for the doors, the notches are cut 1/4" in from the wheel well edge and the length of the full white tubing and pin: which is about 2". I initially cut the pins 2 1/4" long but they only need to be a total of 2" (1 3/4" for the straight part of the pin and the 1/4" 90 degree bend).
The notches in the wing will also keep the hinge pins from falling out.
While off the wing, there's nothing holding the pins in the white tubes so they'll fall out easily if you don't hold the panel level when moving the panel to the wing.

pic 5-8:
Here's all the screws holding the panel in place.

pic 9-11:
All doors functioning.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Sam what radial are you putting in the plane I was just at rc showcases home page they have an awsome video of the rcs 150 on the test stand man what a sound I wonder if you can make the ignition miss a little to make them spit and sputter a little at start up Or maby belch out some smoke that would be cool.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Yo Jeff,
As I mentioned previously, I'm hoping for the RCS 250 radial.

==================================
Center wing (cont)

Gear doors (cont)

pic 1:
I decided to add another 1/16" thick ply for a lip on the other side, also, as maybe the wind may force the front door under the panel cover.

pic 2:
Got the left side door/panel assembly done.

pic 3:
Slots on the left side of the wing for the hinge pins.

pic 4-11:
Main doors done.
Drilled holes into the door hinge part with a #54 bit and used some #0 screws along with the CA and epoxy.
Picture 5 has a small surface defect on the panel cover near the LE of the wing and isn't a hole in the wing (easy to patch).

pic 12:
some 3/4" diameter aluminum solid rod from Metal supermarkets to make engine stand offs.
http://www.metalsupermarkets.com/msc-home.aspx
I had to go there to get a 6" X 5' U shaped girder for my daughters old house and figured I'd get some standoff stock.
Only 5 bucks for a one foot section and they look like they are nation wide.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

hi Sam post the video put the video !!!!....;)

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Center wing (cont)

Gear doors (cont)
Air cylinder assemblies:
Next was designing the air cylinder assembly to actuate the doors.
The manual suggest using robarts 165 air cylinders with 1" throws but they are, presently, out of stock.
Fortunately, I previously purchased Darrell's (Sierra's retracts) air cylinders with 1.5" throws.
The cylinders were too long to put in vertically so I had to mount them horizontally.
I used great planes bell cranks (#GPMQ3920) to convert horizontal motion to vertical motion.
Fortunately, I also had these on hand (dubro's look like they are identical to GP's).
I used a 4/40 clevis on the end of the cylinder shaft (already threaded).
I also used that nice 1/8" thick ply that we cut out of the retract mount area and cut it in half (length wise) for the air cylinder assembly tray.
I needed a longer throw on the bell crank so I used some adjustable servo arms out of the scrap box and screwed them to each side of the bellcrank using hex head servo screws. This gave me a 1 1/2" throw along a 90 degree movement.
I connected the other side of the bell crank to the hole in the door hinge with a dubro 2-56 swivel bell link (#860), some 2/56 threaded rod and a dubro threaded ball link (#181). Ball links were used since both the door and bell crank create a compound arc and I figured this would eliminate any binding versus two clevises.
The inside air cylinder assembly is mounted to a ply rib but I had to cut two triangular pieces of 3/8" thick ply cut 1 1/2"x5/8" to get the air cylinder to be perpendicular to the wing surface.
The triangular cut ply was epoxied to the rib and the air cylinder assembly is screwed to the triangular ply, thus making the air cylinder assembly removable for future maintenance.

pic 1:
Here's the parts to make up the bell crank to get a 1 1/2" throw.

pic 2:
Here's the four sets of air cylinder assemblies.
Each set are mirror images of each other.
Since the air cylinder must follow an arc that the bell crank follows, I screwed one side of the air cylinder mount in the center of the mount hole and the other at one side of the hole when the shaft is all the way into the air cylinder. I tightened the hex head servo screws and then backed off about a 1/2 turn to allow the cylinder mount to move slightly to follow the arc.
All the backs of the hex head servo screws were cut off and ground flush on the cylinder mount as well as on the bell crank.
I also cut a shallow curve on the top of each inside air cylinder assembly panel: in the closed position, the wheel comes close to the ply so I cut some off to insure they never touch.
The air cylinder also is mounted low on the tray so the wheel will not hit the air cylinder. The wing curves right where the air cylinder goes so it's a nice recess to keep it away from the wheel.

pic 3-5:
The first air cylinder assembly mounted to the inside door on the right wheel well.
You can see the triangular ply in pic 5. Having the air cylinder assembly tray vertical also gives some extra room for the folding wings and wires to pass through the rib.
I measured the travel needed to close the door and I'm getting 1 1/16" needed.
With the extra throw of 1 1/2" on the air cylinder, this will ensure that the doors stay closed and not pulled up by air pressure.
With the 1 1/16" throw needed for the doors, it may be difficult to get the doors to move the full distance plus stay closed with the robart 1" throw air cylinders.

pic 6:
Closed position.

pic 7:
A true warbird!
A hawk looking for prey in my backyard (center of picture).

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Center wing (cont)

Gear doors (cont)

pic 1/2:
I installed the air cylinder assemblies in the left wing, connected all the air lines up and tested it.
I had the air lines backward for going to the air valves controlled by Jomar gear/door sequencer.
I also had a problem with the scissors on the gear: one was binding and I called Darrell and he said you need the weight of the gear and wheel for proper operation which means putting the wing 'right side up'. I also found that moving the adjustable collar that the scissors connects to by about 1/32" towards the mounts also fixed any binding. Moving this collar also determines how far up the retracts go so if your retracts need to go up farther into the wheel well (assuming you have any space between the oleo and main spar) then move the collar AWAY from the mount and TOWARDS the wheel.
They worked great when I put the wing 'right side up'.
I used robarts black and amber air lines for 'visual' identification of gear versus doors.

pic 3:
I find a heat gun on the air lines for about 5 seconds temporarily expands the lines to they are easy to get onto the 'T' fittings.

=============
Tail door.

pic 4:
I cut the tail door in half.
Since the CF is black, I put masking tape down the middle and used a flexible ruler to make the cut line.
Fortunately, I visually checked the line and found that it bowed away from the 'visual' line.
The bow was from the flexible ruler following the outer compound curve so I made another line from the other side and divided the two bowed lines in half (length wise) to get the center.

Video of the main gear/doors operating:
I had to get close to the wheel due to not much room so I had to put the camera 'on end' but you get the 'idea'.
I'll need to speed up the sequence for the gear on the 'down' phase.

http://www.rcuvideos.com/video/F4Uco...geartest02-AVI

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

sam compliments for the work "very well made and cared for. but that is fine and Jun on up quickly? ... cmq remains an excellent job ...

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

at6:
Thanks, dude.

===================

Center wing (cont)

pic 1:
I added a second robart large tank to the wing.

==========
Fuse (cont)

pic 2/3:
The kit provided wing bolts were installed.
The holes are already in the wing and first layer of ply: I used an 1/8" drill bit to finish off the hole into a large mound of epoxy (like) material on the bottom of the wing mount in the fuse. This was finished off with tapping the hole.
The bolts are 4mmX60mm (about #8X2 3/8" long): I'd like to have put some standard thread bolts in but #8's are hard to find that are 2 1/2" long.

pic 4:
The second layer of kit ply was added to the firewall.

============
Tail feathers (cont)

pic 5/6:
I was going to wait until adding the vertical stab until my missing aluminum stab tube was sent to me from comparf.
I wanted to used the horizontal stab as a reference to put the vertical fin on but the two surfaces where the bottom of the fin is glued to the top of the fuse are very large so I figured that they will 'self level' themselves.
I put extra ply into the inside of the fin and drilled lots of holes in the bottom of the fin and top of the fuse to give the epoxy some 'tooth' on binding the two surfaces.

pic 7-9:
I first sanded both surfaces to remove the molding lines.
I just 'buttered' both surfaces with a thin layer of epoxy and set the fin on the fuse.

pic 10:
After the epoxy dried, I drilled/screwed eight hex head servo screws into the fin from the inside of the fuse.

pic 11:
There was flexing where the fin met the fuse when I pushed on the top of the fin so I used epoxy and micro-balls to epoxy a piece of 1/4" thick light luan board inside the fuse where the flexing was occurring.
This just about eliminated any flexing of the fuse.
I often see the tails of corsairs waggle on fast flybys and wonder if that large rudder is flexing the small fin.
Anyway, I think the extra weight back there is worth it to make sure the fin doesn't snap off or crack.

=============

pic 12:
Went to harbor freight and picked up some 'hard to find' 25" long 1/8", 3/16" and 1/4" diameter bits for those holes that I sometimes need to drill into wing ribs for nav lights.
The 20 oz gravity feed gun was only 12 bucks and does a great job of applying water base paints on those large surface areas.
This paint gun is an incredible buy.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

tail feathers (cont)

Rudder (cont)

pic 1:
The rudder is the only place that I'm using a digital servo to prevent that inherent wiggle in corsairs (hopefully!).
The servo is Hitec HS-5645mg with 168 oz torque.

pic 2:
The CF tube with rudder control rod and washer to lift the rod a 1/16" above the fuse surface.

pic 3:
The inside of the fuse with a ball bearing and ply support epoxied to the fuse.

pic 4:
To make this assembly removable, a 3/8" collar from ACE hardware is secured to the CF rod (though not necessary since the rudder will hold the CF rod to the fuse).
The 4x40 threaded rod is 2 1/8" away from the rudder control rod. Initially it was about 1 3/4" away but I moved it farther down as the sides of the rudder tray/vertical fin support was interfering with the control rods.
The servo tray/vertical fin support is, presently, dry fitted.
A balsa vertical fin support also still has to be epoxied into place.
The linkages at each end of the 4X40 threaded rod are all heavy duty ball links.
Two 1/2" long brass tubes were cut to hold the ball links at the proper location with locking nuts on all bolts.

pic 5:
Top rudder support screwed to the vertical fin.

pic 6:
Plenty of deflection (for those deflection shots!).

pic 7:
You can see why I'm putting extra ply support into that small vertical fin supporting that huge rudder!

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Sam, Its a corsair, its gonna wiggle no matter what.
Great job puttin this one together. I have one on the way
EvanQ.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Agreed. The signature 'wiggle' is apparently due to disruption of airflow over the rudder caused by the canopy.

You are doing a fantastic job Sam, keep it up!

Goose

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

thanks for the compliments.

Check out Evo's web site:
http://www.evoshangar.com/
He posts all his work on his web site.
Presently, he's doing a Do-335: it looks like a Yellow's kit with all the main work done (ie, sheeting wings, etc) and that drive shaft to the back prop is fantastic. This is going to be one cool plane.
I've been watching this guy's work since he posted his P-38 and he makes me look like a rookie: He does fantastic work.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Tail feathers (cont)

Rudder (cont)

pic 1:
My rudder hardware package was missing so I used thinner wire than what's in the kit so I thought that I'd do a 'bowling ball' test on my thinner wire. The wire didn't bend so I should be OK with it.
Comparf just mailed me the rudder hardware kit and I still may add the thicker wire ( I hate redoing something twice!).

pic 2-4:
I epoxied the rudder servo tray/vertical fin support into the fuse.
I put all parts in place first and then added the epoxy with an acid brush mounted on a dowel to reach into those tight quarters.
Since the tail gear former hasn't been epoxied to this servo tray, I used the former to align the tray/fin support while the epoxy dried.
I kept the two parts separate because if the former and tray were epoxied as one, I'm not sure I could get them into their proper position.
I only put epoxy on the vertical fin support and none on the servo tray: I figure, once epoxied to the former, that will be good enough to hold the tray in place.
The ply fin former goes up through the fuse and supports the vertical fin for about 2".
I won't be adding any more epoxy or FG cloth as I don't think there will be a lot of stress at this location.
The retract former, though, will be getting FG cloth for extra strength.

pic 5:
There's about a 3/8" thick tapered balsa used to support the rest of the vertical fin.
I had to cut off about 1/2 the width at the bottom (where it meets the ply support) so it wouldn't interfere with the rudder movement.

pic 6:
Vertical fin support epoxied into place.
I used micro-balls: There was a small gap between the support and vertical fin and I filled the gap in with micro-balls.
I didn't want to force the sides in as it probably would distort the fin plus it would reduce the amount of space for rudder movement.

===============
Elevators.

pic 7:
The elevator servo tray had to be trimmed as shown in the picture.

pic 8:
Dry fit of elevator servo tray with two hitec HS-645's.
The tray goes on the near side of the recess in order to clear the horizontal stabs support tube.
Initially, I put the servo arms facing outward but they hit the sides of the fuse so I reversed them (too lazy to cut wider holes in the tray!).

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Plane rack

pic 1:
After installing the vertical stab, it's getting difficult to work on the fuse.
It got up to the 50's today so a good project for outdoors.
This afternoon I went to HD for parts (it's nice to walk out of a store and spend less than 10 bucks!).
I used 3/4" PVC pipe.
Parts that I got were two straight pipe (10' long), eight elbows, eight T's, four end caps and some copper pipe insulating material.
The long side pieces are 48", the front cross piece is 15" and the back piece is 10".
Each vertical piece is 12" with double layers of insulation taped on the PVC.

pic 2/3:
I made the four legs removable.
The front legs are 9" and the back is 8" with end caps on all four legs.
The legs are high enough to cycle the retracts or put the fuse on its back with clearance for the rudder.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Tail feathers (cont)

Tail gear doors;
I'm opting to use robart #350 large 1/4 scale door hinges instead of the kit provided hinges.
Unlike the main gear doors that are are straight at the door hinge, the tail doors have a compound curve and the robart large hinges can handle this kind of door.
The manual shows the doors cut into a total of four doors: this would reduce the amount of compound curve and the kit provided hinges would probably work for four doors.
I'm keeping each door half as one large door.
I looked through my corsair book and didn't find any 'four door' set up: This doesn't say that four doors didn't exist but I'm sticking with two doors as it simplifies installation.

pic 1:
Initial felt tip location of where the hole in the doors have to be cut for the wheel.
Presently, I used two screws through the fuse to hold the tail gear former to the fuse to get the proper location of the wheel hole in the doors in the UP position. I'll epoxy the gear former in later but for now, I want to be able to move the gear out of the way to make it easier to install the hinges to the doors/fuse.

pic 2/3:
Dry fit.

pic 4-6:
I used four small bolts/nuts to hold the hinge to the door and fuse side.
Due to the severe curve of the fuse to the door, a 1/8" thick ply was needed between the hinge and door on the front of the door and a 1/4" thick ply was needed between the hinge and door on the back of the door.
I mounted the door side of the hinge first, the edge of the hinge being about 1/8" from the doors edge.
After the hinge is mounted on the door, I used a divider (like a compass only points on both ends) for the distance from the hole in the door side hinge to the hole in the fuse side hinge: I then place the door in the fuse with a 1/16" gap and used the dividers to locate where the hole in the hinge is on the fuse side.

pic 7-11:
The right door installed.
I had to put about a 45 degree bevel on the inside corner of the door and outside corner of the fuse so the door edge wouldn't snag the edge of the fuse.
Epoxy will also be used to re-enforce the hinges.
The bolts that are the hinge pins were put in from the inside of the door facing out so the pin bolts can easily be removed so the doors can be removed for future maintenance.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Batteries

pic 1:
My batteries just arrived from batteries america:
http://www.batteriesamerica.com/
The two large packs are D cell 4400ma, 6 volts each pack.
These are for the receiver (8800ma's should be enough!).
The next large one is a C cell 2000ma, 6 volts for the 250 radial (hopefully!).
The last two (yellow) are 1700ma, 6 volts are for the Yellow P-40 (whenever I get to it!).
I use all nicads: they're simple (like me!) to use, and, with warbirds, might as well add useful weight up front.
Having 10 D size and 5 C size batteries on the nose should definitely compensate for that tail wheel servo in the back!

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Batteries (cont)

pic 1:
The packs must have been charged when sent: only took 22 minutes for full charge.
I screwed up and should have gotten the flat stack versus '2 over 3' battery packs: they stick up on the tray: at the same location where I have the two air tanks mounted on the wing. I'll have to make another tray about 3" wide for the batteries and mount it forward of the present receiver tray. I don't want to move the receiver tray forward as I want to keep the fuel tank over the CG. That's going to make the receiver tray pretty empty!

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Sam why don't you just pull that tray out and strap them to the sides of the tank it self. Would that be possible.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Incredable attention to detail especially fitting the gear and gear doors. My hats off to you. My question relates to the gas fuel tank that's not in an isolated area. Is the fuse vented well enough to remove gas vapers in case of a leak from building up inside the fuse and causing an explosion triggered by servos, etc????? Has there ever been a case if this??? I may run into this on my 190 and was wondering of any special precautions are taken.

Dave

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Bandit,
That's a good idea but I have my two air cylinders there that operate the canopy.

Dave,
I've never heard of any explosions due to gas fumes: also, if the fuel lines are properly connected, there shouldn't be any gas fumes.
The sliding canopy and tail doors should provide enough ventilation.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Tail feathers (cont)

Tail gear doors (cont)

pic 1:
The left side is a mirror image of the right door.

pic 2:
A dubro #181 ball link installed on the door hinge.
The tail doors will be air operated.

pic 3/4:
Doors installed.
I'll have to sand along each door center as the doors, presently, overlap each other.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Sam,

Is that going to be a servo or air operated system for the TW doors? Mine will be air.

Barry

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Barry,
Air.

RE: COMP ARF 110" F4U ARF WITH FOLDING WING ASSEMBLY
 

Sam,

Yeah thats what I thought. I don't think you or I have room for a servo operated system. Plus I already have the Seirra sync valve and my air lines run. I also am going to be using the same hinges. What length air cylinder are you going to use. I was thinking 1/2" travel would be plenty.

Barry