Ziroli p-47 92" blown up to 110"
02-27-2014, 02:40 PM
#29
Fuse (cont)
The paper templates were pulled off and the formers were epoxied to the wing saddle and crutch.
Spruce 1/4" square stringers will be used from F-1 to around F-5 (back of wing) to handle the 15-20 HP engine. Four to six spruce stringers will be distributed evenly around the fuse and run to the tail. The rest will be balsa stringers. The removable fire wall and the sub fire wall are 1/2" thick ply, F-2 to F-4 are 1/4" five ply and the rest of the formers are the 3/16" thick lite ply (save the two tail formers that the tail gear will attach which are 1/8" aircraft ply).
Some kerf cuts were needed on the sharp curve from F-3 to F-1.
As previously mentioned, the fire wall was extended 1 1/4" past the plans to make it easier to balance at the CG.
Last edited by samparfitt; 02-27-2014 at 02:48 PM.
02-28-2014, 11:46 AM
#30
Fuse (cont)
Stab saddle:
I looked everywhere for the the cut out piece SS-1 and finally found that it's not a template in the plans. Fortunately, it shows up on the fuse side view so I just xeroxed it and cut two SS-1's and epoxied them between F-11 and F-12. I just talked to Darrell and he says the tail gear is mounted on a horizontal plate so I just cut a clearance hole in F-11 and epoxied these two formers along with the SS-1 parts. Former F-10A (part of the gear support) won't get glued in until the gear arrives. Darrell says they should go out today or Monday.
Stringers (cont)
I like these 1/4" square stringers, lots of mass making them rigid.
The top fuse stringers were glued along with the small, top former F-4A.
Five butter containers, each with 7 lbs of lead, are keeping the crutch level and warp free on the risers.
Last edited by samparfitt; 02-28-2014 at 11:49 AM.
02-28-2014, 04:49 PM
#31
Fuse (cont)
Did a little research and former F-6 needs to be narrow. I still had the paper template and put it back on the ply and used a dremel cut off disk to reshape the former. This area was narrow to help the pilots see behind the plane.
The angled former F-7RB was then epoxied between F-6 and F-7 and more stringers were added.
MMM; I should have re-notched former F-8 so the stringers were straight.
Last edited by samparfitt; 02-28-2014 at 04:51 PM.
03-01-2014, 10:39 AM
#32
Fuse (cont)
Outer wing saddles:
The outer wing saddles were notched to fit the fuse and epoxied. The bottom of the formers for the belly pan were cut to a 1/4" of the outer edge to make removal easier, after sheeting is done.
Belly pan formers:
Some pieces of 3/32" thick balsa CA'ed to belly pan former F-3A and then CA'ed to F-3.
Fuse side former F-7A epoxied at an angle and then belly pan former F-7B CA'ed to F-7A with same 3/32" thick balsa spacers.
Stringers:
As with the top front, the bottom front to the back of the wing saddle gets 1/4" square spruce for stringers. The front of the wing saddle is only about 6" from the fire wall so some extra strength around this area will help support that 15 HP vibration. For any belly landings, the spruce will also help prevent any cracking to the fuse sheeting.
Last edited by samparfitt; 03-01-2014 at 10:41 AM.
03-02-2014, 07:37 AM
#35
Fuse:
Stringers:
Finished putting in the remaining stringers except on the tail's bottom side where I need the tail gear to properly glue in the gear formers.
Functioning canopy:
A lot easier installing the framing for the canopy rails now before the sheeting is applied.
Lucked out on where the formers are as each end of the canopy rails ends at a former. I notched the formers 1/16" deep to accept the 3/16" square brass rails (plus 1/8" thick sheeting) and glued another piece of 1/4" square spruce stringer to sandwich in the rail. The stringers will also support the sheeting so it doesn't bow or break.
Once sheeting and glassed, it will be easy to cut/sand the slot for the rails.
I normally used sullivan's flexible push rods to move the canopy so some holes were drilled in the formers in case I need some routing space for the push rods.
Planking:
Before planking, I sanded all the formers and stringers to even out all the surfaces.
Using carpenters glue, I laid the first 1/8" thick sheeting (4"X4') so it aligns with the cockpit's top side. Needed lots of clamps to hold such a long piece of planking in place. The paint sticks work well to distribute a uniform pressure along the edges and keeps the edges from scalloping.
The front final 4" has a compound curve so some serious clamping was needed in that area.
The small C clamps come in handy for those tight places where a 'regular' clamps won't reach.
Last edited by samparfitt; 03-02-2014 at 07:46 AM.
03-02-2014, 10:44 AM
#36
Fuse (cont)
cockpit area of razor back:
Some 1/64" thick ply was cut/epoxied to the front of the razor back. Thin sheeting was needed so the planking can easily overlay the back edge of this ply area.
Planking (cont)
The same size sheet was applied to the opposite side along the cockpit edge (no picture).
A 4" wide section was glued from the front of the cockpit to the fire wall. Those nice wide 1/4" stringers make it much easier to pin along the inside edges of two sheets where clamping is impossible and tape may not hold this fairly tight curve.
Last edited by samparfitt; 03-02-2014 at 10:46 AM.
03-02-2014, 01:39 PM
#37
Fuse (cont)
Planking (cont)
The sides are pretty flat so a third full 4' long sheet was sistered below the top, right sheet.
The last plank needed for the top from the cockpit to the fire was secured.
The usual procedure to bevel the sides about 30 degrees to get good mating between sheets.
Some warm water from the basement sink gets the sheeting pliable enough to bend around the curves.
The carpenters glue is hard enough after three hours to remove the clamps and proceed to the next plank.
Last edited by samparfitt; 03-02-2014 at 01:43 PM.
03-02-2014, 06:52 PM
#38
Fuse (cont)
Planking (cont)
Both sides now planked with two 4' long sheets on each side.
Next was the wing saddle area with a 42"X4" long plank.
The opposite side was dry enough to add a 2' X4" to cover back to the end of the fuse.
Cockpit/razor back area:
The other side finished with the 1/64" thick ply.
Stab/elevator:
Got the plans and parts laid out.
03-03-2014, 08:53 AM
#39
Fuse (cont)
planking (cont)
I pre-cut the sheeting around the wing saddle and may have cut a little too much off and will have to fill in some planking, later. A hole was necessary to get any kind of clamping done.
There's not a whole lot of stringers around the belly pan so the sheeting edges are mostly not supported: I probably should have cut the sheeting edges to end on stringers.
The balsa sheeting overlaps the 1/64" thick ply around the front of the turtle deck.
With the multiple curves on the turtle deck, planking is cut to align with the stringers.
Planking on both sides of the tail section came up about half way to the stab saddles so the sheeting was sanded to match the stab contour.
Last edited by samparfitt; 03-03-2014 at 08:56 AM.
03-03-2014, 05:04 PM
#40
Fuse (cont)
Planking (cont)
A large triangular sheet to follow the stringers went just before the tail wheel gear opening.
The last two sheets along the bottom of the fuse. These are 42" long and, by now, the lines between the sheets are varied. Tic marks are put at each former on the existing sheet and then transferred to the new planking. The width at each former is measured and transferred to the new planking. After cutting, the planking usually fits the area very well. If I screw up, I CA some of the cut off sheeting and re-cut.
Turtle deck:
After doing each side, the top went easy with some soft sheeting after running the plank under the basement sink's faucet, even 1/8" thick balsa will bend when the really soft grain is used.
The top curve of the turtle deck was done in pieces, spanning each former to get an accurate fit.
Bottom of fuse:
The last sheet was applied.
The only area remaining is where the tail gear formers still have to be inserted.
This is one big plane:
Just the fuse is my height at 6'2" and about 19" at the top of the turtle deck.
Last edited by samparfitt; 03-03-2014 at 05:07 PM.
03-04-2014, 06:43 AM
#42
Fuse (cont)
Some 100 grit sand paper wrapped around a paint stick smoothed out most of the planking. Some easy sand will be needed for filler.
Belly pan cut out and cleaned up. Some extra sheeting will be needed to fill in around the LE of the wing area.
Bottom of tail section will be finished after the tail gear arrives.
03-04-2014, 12:44 PM
#43
Stab/elevator:
1/4"X1/2" spruce will be used for the spars. In addition the TE joiner spar is from 1/8" thick aircraft ply and another joiner spar from 1/8" aircraft ply will join the main spars. The spar will also be sheer webbed on both sides of the spar. Some serious G's will be on this plane with a 15 HP motor at speeds around 130 MPH.
The plans were laid out and spar notches cut in the 1/8" thick balsa ribs.
Stab TE:
Since the TE tapers, I needed a nice straight line to insure both ends are straight so the spar was epoxied on the plans where the main wing's spar is located. The 1/8" thick aircraft ply was epoxied to the two TE halves.
A secondary piece of 1/8" thick balsa was glued to the ply to give the needed 1/4" thickness to the back of the ribs.
A notch was cut in the center of the TE for the vertical fins main spar.
Scale hinges:
1/8" thick aircraft ply was cut into four hinges that will be mounted on the stab side. The ends need an ogee type curve for proper elevator movement. The hinge hole is 5/8" from the stab's TE surface.
On the elevator side, sullivan's goldenrod #506 (yellow part) is sandwiched between the elevator's LE, two half 1/8" thick balsa on each side of the yellow rod and then another 1/8" thick balsa sheet as a sub-LE. A 1/16" piano wire fits perfectly in the hole in the yellow tubing.
Four pieces of 1/8" thick balsa was tac glued and cut to make the needed 'sandwich' parts.
Parts were epoxied and clamped to an L angle to insure they are straight.
Last edited by samparfitt; 03-04-2014 at 12:52 PM.
03-04-2014, 06:24 PM
#45
B-squared:
Thanks,
Even us old folks can get things done!
I only work half a day....12 hours and I usually take off on the 8th day.
I'm like the average 18 year old male; only all my thought is focused on building. Like the 18 year old, if I'm not 'building', I'm thinking about it!
Reminds me of the story about the 6 year old boy who asked his mother, while pointing to his testicles, are those my brains? She replied, No, but they will be when you get older.
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Stab (cont)
Sequence for me works well:
The center and two outer ribs (with the raised tabs) are first glued to the TE.
Then the LE between the center and outer ribs.
Then each rib can be sanded to fit between the LE and TE, doing the rest of the ribs with raised tabs and then the remainder ribs. This insures a nice straight LE.
The outer balsa wing tips were glued in place.
The top spars were dry fitted with the outer ends sanded to a taper to match the TE.
After the spars were glued, then the center spar connector, new 1/8" thick aircraft ply was glued in place; this spar connector should virtually eliminate any stab folding (along with the sheer webbing and the ply TE connector).
Weights used to insure stab remains flat along with an L angle bar clamped to the TE to insure it is perfectly straight.
Last edited by samparfitt; 03-04-2014 at 06:49 PM.
03-05-2014, 02:11 PM
#46
Stab/elevator (cont)
Stab:
Initially, I was going to use 1/16" thick balsa to cover the stab but I found it kind of weak on the B-25's stab so I'm using 3/32" thick sheeting. I found some very lite weight sheeting that's 4' long. In the picture the sheeting on the right is rock hard (which I find to usually be a gray color) and will be used for the wings. A full sheet was glued from the TE to the main spar with the grain parallel to the TE. Two sheets were needed for the front sheeting from the main spar to the LE. This sheeting's grain ran parallel to the main spar. The stab was weighted to insure it stays level.
The two spars and connecting spar were glued to the bottom of the ribs.
Elevators:
The two servos will be put inside the tail of the fuse and control rods will link to two carb fiber solid rods. The CF rods will slide into brass tubes that will be glued into the ends of the LE of the elevators and secured with screws. To have enough thickness on the LE for the brass tubing, I had to glue another 1/4" thick piece of balsa along the whole length. The brass tubing is slightly larger than 3/8" diameter so I used a 3/8" forstner bit to drill out the end of the elevator's LE. The sullivan yellow tube made a good guide for the forstner bit. I drilled down about 3". To make the brass tube fit the smaller drilled hole, I just sharpened the end of the tube and twisted it into the existing hole. You can do crap like this with soft balsa wood as the tube cut its way into the hole.
I'll have to mod the rudder's LE as it will need a notch where the CF rods will be located.
Last edited by samparfitt; 03-05-2014 at 02:16 PM.
03-06-2014, 04:12 PM
#47
Stab (cont)
Since about an inch has to be cut off the front center, some soft balsa block was glued in that area before sheeting.
Sheer webbing using 3/32" thick balsa on both sides of the spar.
Bottom of the stab sheeted from the main spar to the LE.
Elevator (cont)
The 1/8" aircraft ply was paired with one 1/16" thick G-10 for some extra safety.
The scale hinge locations were marked on the LE of the elevator and these rectangular blocks were cut out via a scroll saw. These blocks will be used on the stab side for the hinge.
The normal straight piece of 1/64" ply for the TE needed a mod since the entire TE is curved. I epoxied the three 1/8" thick balsa pieces making up the TE and then used it as a template to make two 1/64" thick ply center pieces. The 1/64" ply got sandwiched with 1/8" balsa TE and then the outer end of the elevator got another sandwich of two more 1/8" thick balsa pieces and the inner end of the elevator got sandwiched two 3/8" thick balsa pieces. This makes the TE large enough to match the LE of the elevator. The thin ply will keep the TE from warping, I can sand a nice fine line on the TE plus it helps keep 'hanger rash' to a minimum.
Last edited by samparfitt; 03-06-2014 at 04:18 PM.
03-07-2014, 12:50 PM
#48
T7,
Gotta' do something when it's cold out!
============
UPS guy just showed up....ahhhhh.
Gear came in from Darrell.
Usual great looking gear.
The shrink bar pulls up the oleo about 1.5" in the up position.
Those 7" wheels should have no problem going through tall grass!
Last edited by samparfitt; 03-07-2014 at 04:04 PM.
03-07-2014, 03:26 PM
#49
Elevators (cont)
The LE and TE were epoxied together.
Built up the trim tabs using 1/8" thick lite balsa and also added 1/8" thick ribs (general stock balsa sheet as no rib templates in the plans).
Another 1/8" thick balsa sheet added to the LE to get the proper distance to the stab TE and also proper radius, once the LE is rounded over.
Before sanding, I cut the tip off the elevator and epoxied it to the stab.
Before/after sanding of one of the elevators. An 8" belt sander worked best to remove all the bulk balsa; an aggressive machine so care must be taken but it flattens the entire side so the whole surface is flat.
The LE had to be sanded until it's about an 1/8" thinner than the stabs TE, since I'll be sheeting both sides of the elevator with 1/16" thick balsa. The LE won't be rounded over until the top/bottom sheeting is added.
Hinges:
The 1/8" thick aircraft ply, 1/16" thick G-10 and the sullivans yellow tube were CA'ed into one part. Only dry fitting, so far, to the stab.
Some 1/16" thick lite balsa sheeting on the top side of one elevator using carpenters glue.
Last edited by samparfitt; 03-07-2014 at 03:30 PM.
03-09-2014, 11:39 AM
#50
Elevators (cont)
For possible future use, I installed two 1/8" thick aircraft ply hard points in the elevators, in case my 'hidden' linkage has problems.
Sheeted the bottom sides of the elevators and sanded the TE to the center's 1/164" thick ply and rounded over the LE to a constant radius.
Stab:
Epoxied the hinges into the stab and sistered some 1/8" thick balsa on the top and bottom of the hinge and sandwiched some 1/4" thick balsa on the side of the hinge. Had the elevators attached to insure wire pin alignment as well as even space between stab and elevators.
Sheeted the remaining bottom part of the stab.