Ziroli p-47 92" blown up to 110"
03-09-2014, 11:53 AM
#51
Tail gear install:
With the tail gear being mounted horizontally versus the robarts vertical mount, former F-10A was not used. I cut some 1/8" thick aircraft ply for a gear plate to span formers F-10 and F-11. To obtain a distance of about 3/8" between the top of the wheel and the bottom of the fuse, the gear plate (along with the gear) is at about a 30 degree angle to the horizon. Six #6 bolts hold the gear to the gear plate and epoxied in place. A hatch cover will be made to gain access to the six gear bolts.
As I did with the Corsair, the HS-645 servo is being mounted directly to the tail gear arm. The servo tray was made with some gear mount stock that was cut to the exact width of the recess in the tail gear arm, two pieces of 1/8" thick aircraft ply was cut to bridge the space from the gear arm to the servo, the parts were epoxied and then two #6 screws were used to secure the servo tray to the gear arm. Some more gear mount stock was epoxied to the tray for mounting the servo. In the retract position, the servo and mount are about vertical inside the fuse.
Last edited by samparfitt; 03-09-2014 at 11:56 AM.
03-10-2014, 07:06 AM
#52
Stab:
Some easy sand added to the stab tips and the stab sanded to match the contour of the elevators.
The previously cut out blocks from the elevators were epoxied, after a 1/4" thick balsa was epoxied to them and some cutting/trimming, to the stab to fill in the open area of the hinges.
The surface area around the fuse was sanded to dry fit the stab to the fuse. The last former had to be cut in order to slide the stab into the fuse, which will be epoxied in place after all parts are glassed and primed. There is a notch in the TE of the stab for the fin's TE which is the reason for cutting the last former.
Elevator/servo linkage:
This morning, looking inside the back of the fuse, I was wondering if my internal linkage was going to work as there is not a whole lot of 'working' room in there!
I cut away part of the balsa crutch so I could epoxy a servo tray to the ply stab saddle. I used the crutch plans to make two separate servo tray parts, each angled so the servos are resting against the stab saddle. Dry fitting the servos and servo tray parts onto the saddle, there's just enough room for the 4/40 rod to operate between the stab saddles and the fuse walls. A couple elongated holes were drilled into the last former for the 4/40 rod to pass through. The servos are HS-7955's with 333 torque ounces, each.
The tail wheel hits the back of the servos but I can put an axle collar on the air cylinder shaft to limit the throw. The wheel goes far enough into the fuse so the doors will close.
The tail gear doors will give me access to maintaining the servos.
The rudder's LE will have to be modified to clear the elevators linkage.
Last edited by samparfitt; 03-10-2014 at 07:10 AM.
03-10-2014, 12:47 PM
#54
Tony,
I'm planning on having her glassed by the end of this month, although I wonder if I'll make it when I spend all day just figuring and implementing installing the tail wheel and elevators linkages.
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Tail gear (cont)
The servo arm and gear arm were drilled/tapped for 4/40 bolts and four dubro heavy duty ball links were used.
The HS-645 servo is needed as I think I burned out a HS-225 on the carf F4U but the 645 works great.
Darrell uses a unique centering device where a V groove is used to center the wheel.
Interesting guide arm is rectangular instead of round but it all works very nicely.
The control arm moves horizontally for about a 1/2" where a sliding T locks the wheel in the down position.
Elevator servo linkage:
The servo tray parts were epoxied and screwed to the stab saddle and the two servos were screwed in place. Dubro heavy duty ball links used on both ends of the 4/40 rod which has a brass tube as a stiffener.
The elevator side got two 2.5" long 7/16" diameter brass tubes pushed into each elevator end. Each 3/8" diameter CF rod is 2 1/4" long and the elevator side was drilled/tapped for a 4/40 bolt to hold the CF rod to the brass tubing and elevator.
I cut two 1/2" long brass 7/16" tubes to strengthen the CF rod where it was drilled/tapped for 1 3/4" long 4/40 bolts to hold the ball link. A 1/2" long brass tube was needed to position the ball link at the right location on the bolt to enter the back of the fuse.
I cut a 3/4" long 7/16" diameter tube to connect the ends of the two CF rods. This 3/4" tube rotates freely between the two independent CF rods but ties the two rods together for some additional rigidity.
I'm figuring that I don't need any additional support for the center, ends of the CF rod. If I do, I can cut some ply and mount that 3/4" brass piece to the ply and epoxy it to the former.
I binded the transmitter to the receiver and slaved Aux 2 (left elevator) to the right elevator and adjusted the elevator halves to both are in sync. I also tested the tail wheel.
Last edited by samparfitt; 03-10-2014 at 01:42 PM.
03-11-2014, 02:27 PM
#56
Tony,
I don't have the skill sets to do aluminum.
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Wings:
Radical concept (no wing tubes but steel bar stock):
I like three piece wings but, with the P-47's wide stance, any savings of space by removing the outer wings is marginal so I'm going to use a two piece wing. The wing will come apart in the center but I'll more likely just leave it assembled, at least during the flying season. The 92" span is built as a one piece wing so there are no holes for wing tubes so I've decided on a different approach.
I picked up some 1/8" thick by 1/2" wide steel bar stock. I plan to bolt about a 4" long piece to each side of the wing and have one overlap the other and bolt through the two straps. Besides the main spar, I'm adding two more spars: one at the front and one at the rear. (thus, 3 straps for top stress and 3 more for the bottom stress).
The main spar is 5/16" thick by 3/4" thick spruce that is doubled for about 12". The front and back spars are 1/4"X1/2" that are also doubled up for about a foot.
Since the steel bar stock will overlap each other for a couple inches on one wing side, I'll add another 1/8" thick spruce to raise one bar stock. On the top of the wing, the inside available space in the fuse is 8" so all top bars will be 4" with the overlap an additonal 2" longer. The bottom belly pan is wider so I can use about 6" long bars. The bars will not be seen since they will be contained within the width of the fuse.
I'll use bolts and blind nuts to insure no stripping occurs at the connection point.
Ribs:
All the different size spars had to be transferred to each rib and then cut on the scroll saw.
The wing will be bolted to the fuse using four bolts (no dowels) so two ply plates will be at the front and back of the wing.
Nothing's ever easy!
Gear:
The ribs were being notched for all the spars, etc until I got to the ribs around the gear.
The frame assembly for Darrell's gear is inline with the strut. The plans, having robart's gear, the frame assembly is offset to the side, thus some mods will be needed for the ribs around the gears.
I'm guessing that I can glue up the ribs up to the 'gear ribs', and then remove the wing assembly so I can access, take measurements and cut parts as needed to get the gear mounted in the wing.
(similar to the gear problems with the 118" Ziroli B-25)
Last edited by samparfitt; 03-11-2014 at 02:35 PM.
03-12-2014, 11:17 AM
#57
Wings (cont)
Steel Joiner bars:
A reciprocating saw made quick work of cutting the steel bar stock. I was a couple pieces short and had to buy another bar.
Ribs:
With the bottom main spar in place and the risers pinned down (flat wise), the ribs were glued to the main bottom spar making sure the TE was resting on the risers. Rib W-1 is put in last since it has to be angled for the dihedral. Rib W-2 is especially important to be perfectly perpendicular since the W-1 jig is, first, glued to rib W-2 and then W-1 can be later glued to the angled jig.
Ribs W-1 to W-7 are all from the 3/16" thick ply. Ribs W-8 to W-13 are 1/4" thick balsa.
Gear not as bad as I thought it would be:
Laying the gear on the plans greatly aided in getting the ribs cut correctly so the gear will fit.
Rib W-6 needed to be moved inward about an 1/4" so make room for the gear's frame assembly.
Fortunately, rib W-6 and 7 get sistered with two 1/8" thick aircraft ply doublers so the two doublers (W-6A/7A) will be notched to hold the gear mounts and then epoxied to their respective ribs, making the gear install a much easier task than originally thought.
The ribs with flaps were pre-cut on the LE leaving about a 1/4" of wood on each end to aid in future removal of the ribs.
Ribs W-8 to W-13 were stacked and drilled so the sullivan blue nyrod tube can be inserted as a wire guide to the nav lights.
Ailerons:
The ribs for the ailerons were notched differently so the LE will be rounded, like the flaps and will have the top sheeting of the wing extend past the wing's TE, again, like the flaps. Since scale hinges are being installed, this new contour is more scale and doable.
03-12-2014, 04:09 PM
#58
Wings (cont)
Left wing:
The risers were rotated so they are now 1/2" high for the washout.
Three dihedral templates were epoxied to rib W-2. After those dried, rib W-1 was epoxied to the templates.
Some straight pieces of spruce was used to keep some bowed ribs straight while the sub LE 1/4" square spruce spar and the three main top spars were glued to the ribs.
A couple of the TE mini stringers (spruce) were also glued to the ribs.
The two main spars (spruce) for the outer balsa ribs were also installed.
The TE of all the ribs were checked often to insure contact with the washout risers.
Last edited by samparfitt; 03-12-2014 at 04:11 PM.
03-13-2014, 12:07 PM
#59
Left wing (cont)
Rib W-1 was warped at the front so I cut the dihedral brace and LE 1/4" square stringer, applied a heat gun to the epoxy on the front upper spar to straighten out the rib. Later, the cut stringer will be sistered with a piece of spruce.
Gear install:
The two aircraft ply sister ribs W-6A/7A were cut/sanded to sit flush with their respective ribs.
For gear set up, a piece of 1/8" thick balsa and a 1/4" thick balsa was taped to rib W-4 so the wheel would lay flat in the wing. Also, I want a little 'wiggle' room so the gear doesn't touch any surfaces and hang up.
A card board template was cut until it matched the space for the gear and between ribs W-6 and W-7.
A 1/8" thick aircraft ply was cut from the template and laid flush to the gear's mounting holes, which is at an angle to the ribs.
Clearances were then checked to make sure the gear doesn't contact any ribs and will not hit the surface sheeting using a straight edge.
Last edited by samparfitt; 03-13-2014 at 12:32 PM.
03-13-2014, 12:19 PM
#60
Left wing (cont)
Gear install (cont)
Some 1/8" thick G10 (from Mcmasters) was cut the same size as the ply and will be epoxied as a 1/4" thick mounting plate.
A couple mounting holes were drilled, the gear secured to the mounting plate and tested to insure alignments are correct using a manual air pump.
My one front main spar needed some trimming for wheel clearance.
The wheel appears straight in the down position and there is a slight angle to the wing to compensate for the wing dihedral, but I'll have to get the right wing framed, bolt the two wing halves together and make sure, visually, that all is correctly aligned before gluing anything together. For now, all is dry fitted.
I also dry fitted the front 1/8" thick aircraft ply wing spar WS-1 to the ribs. The entire area around the gear will be strengthened, The sub-LE will be 1/8" thick aircraft ply and the main spar as well as the LE spar and TE spar will be boxed with 1/16" ply. The gear mount plate will get two ply supports under it and the entire area will be CF glassed from the inside.
Last edited by samparfitt; 03-13-2014 at 12:35 PM.
03-13-2014, 12:28 PM
#61
Gear Oleo:
The oleo has a separate air nipple that gets air to keep the gear fully extended in the down position. The shrink bar will compress the oleo in the UP position. As with the prototype, the gear will shorted on the ground if the air leaks out.
Right wing:
I got smarter this time and clamped straight edges to both W-1 and W-2 when I glued them up via the dihedral braces.
Sheeting:
The wings are 55" and balsa only comes 48" long so some butt gluing will be needed on the ends of the sheets. With the 1/4" wide balsa ribs at the end of the wings, I can span the last two ribs with separate sheeting.
Four sets of sheeting was glued up.
Two pieces 4' long for the LE edge area and two with two 4' a 42" and a 24" for the TE area. Masking tape holds them together until the carpenters glue dries.
I still have several sheets from Aeroplane works, a kit cutter company that folded after Gill, the owner, died.
03-14-2014, 06:53 AM
#62
wings (cont):
Right wing:
The top spars were glued to the wing so the right wing could be removed from the plans.
A band saw seems to work best on cutting G10.
The gear mount for the right gear was cut and dry fitted (2nd one is always faster).
Dry fit of both wings.
The gear were clamped to the wings and the wings were clamped together.
The main wing spars align with each other and the W-1 ribs are flush.
A straight edge was used to make sure the top of the gear housing doesn't interfere with the top wing sheeting.
Gear was lowered and they look perpendicular and straight.
There are four wing joiners (WT-top/bottom) that will be used to slide into the wings to align them, along with the metal bars to hold the wings together.
Wing to Fuse:
The dihedral looks good as there is even surface contact between the wing and fuse's wing saddles.
Last edited by samparfitt; 03-14-2014 at 06:55 AM.
03-14-2014, 06:32 PM
#63
Main gears (cont)
The two sister ribs were epoxied to their respective ribs.
The 1/8" thick aircraft ply was epoxied to the 1/8" thick G10.
Separate 1/4" thick ply was drilled for the blind nuts, which were epoxied to the gear mounts.
All the holes were re-tapped as, invariably, some epoxy gets on the threads and it's easier to tap now than after install, or worse, stripping threads trying to force a bolt into a blind nut.
The gear were screwed to the mounts and placed between ribs W-6/7 and spot epoxied just on the four corners; gears cycled and wings pinned together again to insure all works and properly aligned.
The bottom of the mounts were then fully epoxied with spruce bracing along the edges.
The front bottom spars were epoxied to the ribs.
For the top bracing, ply and spruce were cut and epoxied to the mounts.
03-15-2014, 10:00 AM
#65
Wings (cont)
Wing joiner straps:
As previously mentioned, the joiner straps are replacing the wing tube.
I'll be using three joiner straps on the bottom as well as the top of the wing (one per spar).
Each spar gets two 1/8" thick by 1/2" thick steel straight bar stock. The two bar stocks overlap by 1 1/4" and were drilled and tapped for two #10X24 button head screws that are used to secure them together. Each bar stock is secured to the spar with four #6X32 hex head screws and blind nuts. One bar stock is bent to accommodate the dihedral. This side also got a piece of 1/8" thick aircraft ply as a spacer to raise one strap over the other. Only the #10 bolts are removed, the #6 permanently hold the straps to their respective wing spar.
Three #6 screws were drilled at an angle on ribs W-1, next to each spar, which are used to tighten the wings together, in case this is necessary when putting in the #10 bolts on the joiner straps. Some JB weld was used to secure the blind nut at the unusual angle. These maybe a lot of extra work so I may also leave a 1" gap in the sheeting and use a strong clamp to hold them until the #10 bolts are inserted.
I ran out of blind nuts; bummer.
I think I over engineered it, but better too strong...!
Last edited by samparfitt; 03-15-2014 at 10:04 AM.
03-15-2014, 03:49 PM
#66
Wings (cont)
Wing joiner straps.
Finished up the top side. I found a few extra blind nuts.
An angle gauge was used to get the correct bend on each strap. The point of bend was put in a vise and an auto body hammer with a flat surface was hit right at the base of the bend so the bend would be crisp and not a bowed bend.
Holes through the steel straps were the exact dimension of the bolts to eliminate any slop and possible wearing of the bolt shafts.
That took a 1/2 day: 12 hours.
03-15-2014, 06:37 PM
#67
Wings (cont)
The big test:
Took the wings apart. Actually it was easier to put them back together as they stuck a little when taking them apart.
I put some wax paper between the wings and put them back together again so I can sheet the top. I'm partial to top sheeting first as it's easier for me to insure washout and alignment, no warping, etc by putting weight on the wing while the wing rests on the risers and plans.
I usually do each wing separately but decided to keep the wing halves together to insure ribs W-1 are always perfectly flush with each other.
Top sheets are ready to be sanded, cut and installed but still need a few other minor things to be done, first.
03-16-2014, 01:52 PM
#68
Wings (cont)
1/4" square balsa used to box in around wing straps and bolt for sheeting support.
One rib was lower than the others and needed some balsa capping and sanding to align with the other ribs.
Right wing:
Cut and used carpenters glue to put the first top sheeting on from the 'double' main spars to the TE. 'Double' in that the spar nearest the center of the wing is back about 4" from the other main spar that runs from the gear to the wing tip. I was going to run some 1/4"X1/2" balsa to make the outer main spar run all the way to rib W-1 but it's best to keep all clutter away from the wheel well as there is very little room between the tire and the top sheeting. I opted to cut the sheeting to run along each spar. Additional sheeting will be glued to the front sheeting to span the wheel well area, which will allow sanding of the surface smooth BEFORE putting the sheeting on the wing.
About 50 pounds of weight should insure proper wash out and unlikely to get any unwanted warps/twists!
With the sheeting virtually flat, the carpenters glue sets up quickly and enough to do the left wing within and hour or so.
Some 100 grit sand paper wrapped around a paint stick insures any defects in the sheeting is removed.
The sheeting was cut 1/8" past the TE stringers. The flaps and ailerons are always sheeted separately.
03-16-2014, 01:57 PM
#69
Wings (cont)
For the sub LE, 1/8" thick aircraft ply was epoxied from rib W-1 to the rib just past the gear housing .The remaining sub LE was done with 1/8" thick balsa.
Some CF sheeting around the gear mounts. Finishing resin doesn't penetrate through the CF so the surface must be coated with resin before adding the CF. A good reason for 1/8" thick aircraft ply sistered to the rib when it gets that thin.
03-17-2014, 12:50 PM
#70
Wings (cont)
Sheeting:
The right wing's sheeting from the main spar to the LE taped and weighted and then the left side was done.
A little water from the faucet over the outside sheeting is enough to cause the outside wood fibers to swell while the inner cells are dry, giving the needed curve for the LE.
The center TE of each wing got the usual 1/64" thick ply CA'ed to some 3/32" thick balsa sheeting and secured to the ribs.
I love that rock hard balsa for wings.
Finished off the sheeting of the last two ribs on each wing tip.
With the top sheeting done, the two wings can be separated to work on the flaps/ailerons.
Flaps/ailerons:
I traced outlines of the flaps/ailerons on wax paper to use as templates and, hopefully, the spray glue will adhere to the wax paper!
Top/bottom sheeting glued up, using carpenters glue, for the ailerons/flaps along with cutting out the 1/64" thick ply for the TE's.
Last edited by samparfitt; 03-17-2014 at 12:54 PM.
03-17-2014, 06:41 PM
#71
Wings (cont)
Ailerons/flaps:
The LE stringers were glued into the flaps and aileron ribs. The flaps have two end ribs that also needed to be glued to the LE stringer.
With a curved TE, all the sheeting (top/bottom) of the ailerons and flaps needed to be tac'ed glued together to get an accurate curve on all surfaces. Some templates were made from the plans and also tac'ed to the sheeting. Some 1/64" thick ply was also sandwiched in the 'pile' so everything got cut at once. The LE's were left long and cut, 'as needed' during the install.
The 1/64" ply was CA'ed to the TE of the flap and aileron's top sheeting using a machinist's square to keep parts flat and in full contact with each other while the CA'ed cooked.
Both top flap sheets were glued to the ribs and LE stringer.
The left aileron also got glued in place.
03-18-2014, 01:24 PM
#72
Wings (cont)
Fowler flaps: spent all morning finding out what doesn't work so it was set aside for now and sleep on the problem.
Figured I'd get something done so the LE/TE's stringers were cut/glued to the wings, ailerons and flaps.
Also put notes in the wings so I don't forget anything!
Together, the wing doesn't seem that long but the width, at 25", is huge; gives the P-47 nice landing attributes.
Last edited by samparfitt; 03-18-2014 at 01:29 PM.
