Vq P-38, Assembly Begins  
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Vq P-38, Assembly Begins - 6/27/2003 6:37:57 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		I was going to get some more flight time on my WM F-82 and VQ A-26 but the P-38 kept saying: 'assembly me, assemble me, assemble me'.
After checking everything out, I did the usual thing of slopping plenty of 30 min. epoxy on the retract, servo, fire walls and outer aluminum rods on the inner/center wings. I did stay away from the fowler flap mechanism: too intricate to accidentaly hose up with epoxy.
I'm impressed by the outer wing attachment.
There is an access hatch to the 90 degree bellhorn to connect the flap servo(use retract servo) via a ball and link. This is not going to be as bad as I thought for transport: It looks like I have two options: 1. open the access cover on the bottom of the wing and attach the ball and socket to the out flap on the outer wing. This seems the best way but the socket may wear with removal for each trip to the field, although it looks like a standard socket that I could buy, and
2. make a small access hatch on the fiber glass fuselage-top shield.
It looks like the center wing will be able to stay with the fuses: which is good since that's where the bulk of the wires are.
Later, I'll decide on which method to use.
There are lots of hatches (10) so I labeled each (L1-5, R1-5) by location and description as well as by orientation since it's unlikely that all those screw holes are in exactly the same place on each hatch.
There's 3 hatches on each outer wing and 4 on the center wing.
Outer wing: 2 hatches for the flaps and 1 for the ailerons.
Center wing: all 4 for the flaps.
After removing the aileron hatches, I was pleasently surpised by the servo mounts already glued on (of course, I added some more epoxy!).
These are hardwood. They fit my JR perfectly.
I only needed to cut a small notch on the back of one so the servo wire doesn't kink.

There are plenty of holes to cut the covering away to get access to holes where screws will be going.
There are 3 small holes that are metal lined on the bottom of the outer wings to drill the holes
into the three aluminum rods to hold each outer wing on. The rods will be epoxied to the center wing. For us old people, the rods are 11 3/4" (two, one in each center of the rib) and 6 3/4" (4, two flanks the longer center rod).
There's also 2 very small (1/4" long) dowels for the alignment at the rear of the rib.
More hole locations(pushing with your finger will find some of these that aren't so easy to see, another negative for us old people!).
Top of center wing:
2 on each side to put the flap servos in.
1 in the middle for attaching the center fuse.
Bottom of center wing:
2 for leads to the flap servos.
4 for attaching each fuse.
1 for the center fuse.
Front:
4 for the 2 3/4" dowels to hold the center wing to
each fuse. These have rounded ends so they go easily into the fuses (nice touch).
Just epoxy them and push them in until the hit the
aluminum rod in the wing.
I noticed that the outer wings have plastic laminated to the ribs where the aluminum rods go.
I assume high strength plastic for the stress that the outer wing will get.

The flap servos have no pull strings to get the wires through but it wasn't any hastle to do it.
I used a long push rod and bent a hook on one end and pushed it through the outside center hole of the rib, put the extension wire on and pulled it through. It only needs a 12" extension but I needed a 24" attached to the back so I'd have
enough to pull it back through.
The only place for the flap servo wire to go is right by the fowler flap mechanism: I was worried that the wire may catch on this so I used metal duct tape to hold the wire to the top of the inside of the wing.
Since there are fowler access hatches, this is easy to do.
That's about all I got done tonight.
So far, this is a very impressive plane: they did their homework on planning and designing this plane.
If she flies half as good as she looks, she'll be a winner.

< Message edited by samparfitt -- Jun 27 2003 2:21AM >

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G. Samuel Parfitt
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CORRECTION - 6/27/2003 4:12:40 PM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		I found 6 more holes while reviewing the instructions. Three more on each side of the center wing to hold the aluminum rods in. I'll probably now opt to epoxy and screw the rods to the outer wings and only screw them on the center wing. Epoxy to the outer wings should keep the rods aligned for the screws to be easily be put in for re-attaching. This would now only require attaching the fowler flap rod and each servo wire (doesn't sound too bad).
When closing up shop, I couldn't resist putting the plane together with center/outer wings, the 3 fuses and horizontal stab. They all fit snug with no problems getting all screws together: very impressive quality control.

_____________________________

G. Samuel Parfitt

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       Post #: 2

FOWLER FLAPS - 6/28/2003 8:29:11 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		Didn't get a whole bunch done: went out flying the A-26.
Attached two of the four 'ball sockets and rods' to the control horn and retract servo in the center wing for the flaps. Used the manuals suggestion and put the semi circle curve on the rod.
I used their quick connect linkage on the retract servos. I had to use a #32 drill for the servo arm hole and then make the servo arm thinner so the quick connect could rotate easily.
After putting the nut on the bottom of the quick connect, I then found that I had to grind off the excess part under the nut so it wouldn't hit the top of the servo when it rotated (nothings ever simple!).
Make sure you hook up your servos to your receiver and check which way the servo arm is moving before you connect the rod up: putting it in back wards always makes unsettling noises!
I put the four fowler flap covers back on the bottom of the center wing.
All servos are now in the center wing.
The fowler flaps on the center section look cool
with the servos moving them (sliding out and down).
Very impressive piece of design work.

I found that the middle aluminum tube in the center wing doesn't have the metal screw guide tubes for the screws like the rest of the total 12 holes have. I have some brass tubing (about 5/32" diameter) which I have to cut and epoxy for the missing pieces (there are only two missing).

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G. Samuel Parfitt

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Vq P-38, Assembly Begins - 6/28/2003 9:17:54 AM   
RangerVorian



Posts: 70
Joined: 12/9/2002
From: Wayne, NJ, USA
Status: offline 		The guide tubes for the middle tubes are further in. They don't line up with the other two. Look for it near the inner covers.

Hope this helps.

_____________________________

Michael S. Carpio
---Abort, Retry, Fail???

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       Post #: 4

SERVOS IN - 6/29/2003 9:19:34 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		Thanks Mike on those two extra holes: had trouble finding them even after you told me about them.
I hooked up the aileron servos. Pretty straight forward. Used one 24" splitter and two 12" extension for the aileron servos. Used that rod with the hook to pull the wire extension from the middle of the center wing to the outside rib.
The supplied clevises look like nice quality(brass) and the push rods are larger than what's normally supplied with other ARF's.
The wire may be a little brittle: bending a 90 degree on one aileron snapped on me.
This may not be the best procedure for everyone but I epoxied the 6 aluminum rods to the outer wings. I plan on keeping the center wing with the booms and there's just enough room to fit it in my car. I epoxied them to the outer wings for 'piece of mind' for myself. You could also go with screwing them all in. I dry fitted them first.
I'm glad I did since one would go in easily one way but not the other (strange). I also marked how far they go in since the tubes have wood in them and any extra epoxy at the end of the tube may keep them from being all the way in. This was the case on one but pushing on it forced the extra epoxy out. I also then push the tubes into the center wing just to make sure they set up properly. There's a little slop in the fit and this insured alignment.
I also don't want to be putting this large a plane on it's back so I used a 1/8" drill bit (the inside diameter of the metal tubes where the screws go) and, after attaching the outer wings and masking them together so they wouldn't move, I drilled from the underside through the screw tubes, through the wing connecting tubes and through the top of the wing.
(the fit between the outer and center wings is excellent).
I then cut about 2.5" 1/8" diameter brass tubing and pushed those into the holes so they protrude out both sides of the wing.
Each trip to the field, I'll have to put these 6 1/8 " tubes in to hold the outer wings on, instead of using the 6 screws. Later, I'll figure out some way of insuring that they don't vibrate out.
This is right where the fuse-top shield goes so they won't be visible. A little unusual but it should work. If I had the vehicle space, I'd opt for screwing the outer wings on. These are accessible but the center wings are where the 2 fuses are and I'm keeping this part of the plane intact during transit.
I finished up hooking up the fowler flaps on the outer wings. The push rod for the flaps go to the servo on the center wing. I will have to connect this for each trip to the field along with connecting the aileron wires.
One thing I noticed is that the manual shows the half circle for the push rod having a radius smaller that the distance between the 2 easy connects. I made my half circle larger so it won't hit the other easy connect: I believe their diagram will have them hitting each other. I hooked up the receiver and all 4 fowler flaps and ailerons are working...cool.
I put the other 8 servos in the plane.
I mounted one of the elevator servos backwards: This should take care of having to use a 'reverse servo wire'. I'm also assuming that the servo moves the same speed and amount in both directions from center.
They have the rudder and elevator pushrods coming right over each other by the servos. For the rudder, I'm opting to put a zag in the rod and connect to the other side of the servo to reverse this one. I didn't do this with the elevator because there doesn't look like there's enough room for that since it's right next to the retract mounts. I had to cut all but one side of the servo arm off so it doesn't hit the retract mount.
Speaking of mounts, the Spring Air #102 HD that came with the plane has a horizontal mounting for the nose wheel that must be mounted between 2 separate pieces of wood. The nose has a flat horizontal one-piece of plywood. I'm going to have to epoxy some wood to build up some mounts for the retract to work.
I haven't gotten there yet but it just occurred to me that 2 splitters will be needed: one for each rudder and then another for the extra servo to control the nose wheel on the center fuse.
I'm going to have to add a few more holes to the center wing to run all those extension from the receiver to the outer fuse servos.
There's no pictorial on where the receiver/battery goes but the center seems logical.

< Message edited by samparfitt -- Jun 29 2003 4:32AM >

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G. Samuel Parfitt

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ENGINES AND TANKS INSTALLED - 6/30/2003 6:07:47 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		On placement of the receiver, I could put one in each boom so save on wires and use as a safety backup.
The throttle tray goes behind the tank, which I epoxied in. I'm using OS FX 2-stroke .91's on this plane. It may seem like overkill but I'd rather have the power and not need it. I'm using Master airscrew 14X7 3-blade props. This works good on the GSP P-47 72" jug with a .91 in it.
The rubber exhaust on the J-tec makes the engine sound like a 4-stroke.
I consider the 46 recommended in the manual as way to small for this plane. .61's would be good but I've got two brand new .91's that need a home.
The engines are mounted inverted and rotated about 10 degree so the edge of the head is about in the center of the fuse. This allow the inverted J-tec muffler (jt-903mx) and engine to be completely with in the cowling with only a hole at the bottom back end of the cowling. The supplied spinners had to be trimmed to allow these large props to fit it.
I'm using Sullivan's slanted front 16 Oz tanks. These are too large to fit so I trimmed the secondary 1/8 ply behind the firewall and this gave me about an extra inch of space. I used blind nuts for the back of the fire wall to hold the motor mounts. As usual, pitch the hardware for holding the engines and motor mounts on and get the allen screws and locking nuts. I drilled and tapped the holes in the motor mount for attaching the engines (extra safety: I've had nuts work loose on the larger engines).
The engines are completely encased by the cowlings which give it a nice scale look.
That's about it for today, too nice not to go flying.

_____________________________

G. Samuel Parfitt

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RECEIVER, WIRES AND RETRACTS - 7/2/2003 7:52:10 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		Only put in 2 hrs of work today and put 14 on the P-38 (sounds like a good ratio!).
Like the A-26, I thought the center fuse forward of the wing was a weak spot so I beef'ed it up. There's only four narrow pieces of 1/16" ply where the wheel rest inside the fuse. 3/8" X 2 3/4" X 3 1/4" light balsa was epoxied on both sides of the wheel well and also on each side in front of the next bulkhead. This re-inforced it up to the retract pad which appears sturdy. I also put 1" triangle balsa stock just below where the leading edge of the wing meets the fuse.
After putting the center top shield on, it appears that the front fiberglass (semi circle) on this fuse should not be cut out. There's some trimming on it so it fits on the main center fuse but that's all.
There's plenty of room for the receiver just in front of the pilots gauge panel. That 3/8" balsa is there so I just glued a shelf on it and rubber banded the receiver to it. I put the
battery pack (1100 MA) down under the formers where the front of the main fuse opens up to a large cavity.
I cut about 3/4" square holes straddling the center rib on the top middle of the center wing and one on each end on the bottom of the center wing.
This allowed me to run the many splits/extensions from the receiver to the center of the wing.
I then fished them with that same hooked wired I used before to get them to the outside rib and down through the hole in the bottom of the wing.
I could then connect them to each servo and insure all is working OK.
My previous reversal of the elevator servo was a useless idea (senior moment). Fortunately, I had a servo reverse extension in the shop. I used a threaded rod to pull the air hoses through.
I had to build two 'shelves' for the nose retract so it could be anchored to the flat plywood that is already there. The other retracts went in with no modifications.
I wasn't familiar with the parts for the nose retract so I called up SpringAir. The steering is a pull/pull system to be connected to a triangular piece of metal that has 3 holes in it (triangle points forward).
There is a black piece of plastic with a wire on it. That goes over the rotating part of the retract, the strut wire goes through the hole in the plastic and the piece of wire on the plastic goes through the front hole of the triangle.
The wire on the black plastic keeps the strut from flopping around when it is retracted. The strut wire is 3/16" diameter so the hole in the black plastic piece will have to be enlarge. The other 2 holes in the triangle are for the pull/pull system going to the servo.
The working oleos will be put on later(ran out of time).
I glued the 2 aluminum tubes and 4 bamboo dowels in the back of the booms for the horizontal stab.
There is a secondary set of holes that these pieces go into inside the booms. The tubes and dowels don't got in half way but only far enough to reach the secondary supports inside the booms. There's only one screw for each aluminum rod: trim the covering off of the hole on the bottom of the stab and you can see how far that the tubes have to protrude. I used a small flashlight to better see the secondary supports inside the booms. I dry fitted them, marked how far in with a pencil and then epoxied them to the booms.
I connected all wires, booms, center fuse, main wing and horizontal stab together.
Looking good.
I checked the CG and it's a little tail heavy so that 'upfront' reinforcement was not just dead weight added. Don't have the oleo's or robart wheels or spinners or props so that may make her balance just about right.

_____________________________

G. Samuel Parfitt

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       Post #: 7

ELEVATOR AND RUDDER HOOKUP TO THE SERVOS - 7/3/2003 7:22:06 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		Nothing fancy here. I just followed the manual.
The rudders have the pushrods offset about 1 1/2" to the center of the booms. This is probably to keep out of the way of the elevator pushrods which are immediately below the rudder pushrods.
No need for a reverser, even though they go in opposite directions when the stick is moved but, since the linkage to the rudders are on the outside of each boom, this negates the opposite movement of the servos.
Check all hinges: my rudders were not glued in.
I used 3/4" servo arms (from center to hole) to get max rudder movement for one engine flying occurrences.
The elevators have 1/2" servo arms. The arms point to the outside of the booms. Again, nothing difficult on assembly: just time consuming since there is little room to work in there.
I'm using regular JR 517/537 servos: I don't plan on any 'stunt' maneuvers.
With the number of wires to each boom and the close tolerances between the booms, center wing and horizontal stab, it appears best to keep this as one piece and only have the outer wings removable.
I'll work on the throttle linkages next.
The engines have exactly 5" from the fire wall to where the spinner goes on.

< Message edited by samparfitt -- Jul 9 2003 4:32PM >

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G. Samuel Parfitt

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PICTURES...FINALLY. - 7/4/2003 7:56:49 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		I hooked up the throttle linkages tonight.
Had to grind part of the J-tec muffler to get free movement through all ranges. Also had to rotate the engine throttle arm about 30 degrees forward to get by the muffler.
Had to also drill and tap a hole in the muffler and drill a hole in a aluminum screw for the pressure fitting for the fuel tank.

First picture shows the OS FX .91.
There's plenty of room for the cowling to cover the engine. Engine is rotated about 10 degrees to get the engine and muffler within the cowling.

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G. Samuel Parfitt

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PICTURE 2 - 7/4/2003 8:02:18 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		Shows the bottom of the center fuse. Battery is in the deep well of the fuse. Retract is on a split raised platform. No oleo, stearing or wheel yet.
It can't be seen but the 3/8" balsa is on both sides of the fuse for extra support. The left well shows the receiver on it's shelf located on the top of the fuse.

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G. Samuel Parfitt

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PICTURE 3 - 7/4/2003 8:05:50 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		The top view of the center fuse. The receiver is on the homemade shelf. Can see the 3/8" balsa re-inforcement that the shelf sits on. The wires from the receiver run to the hole in the center wing split off in both directions. Where to attach the on/off switch and air valve hasn't been decided yet.

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< Message edited by samparfitt -- Jul 4 2003 3:25AM >

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G. Samuel Parfitt

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PICTURE 4. - 7/4/2003 8:08:39 AM   
samparfitt


 

Posts: 1839
Joined: 9/1/2002
From: West Chester, OH, USA
Status: offline 		The left boom showing wires from the end of the center wing going to the throttle, elevator & rudder (left to right). Only retract mechanism is in without oleo and wheel. Also showing the 16 oz tank and OS FX .91.

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< Message edited by samparfitt -- Jul 4 2003 3:16AM >

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G. Samuel Parfitt

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       Post #: 12

<
PICTURE 5. - 7/4/2003 8:13:25 AM