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May 01, 2016, 02:38 PM
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Joker 53150's Avatar
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The fuselage goes together fairly quickly, although it would certainly be faster if the plans were a little more clear for the forward portion. It's often hard to tell where pieces are supposed to go, and it takes a lot of looking back and forth at the side view vs. top view. But I think I've got it mostly figured out. Tite Bond II glue is being used throughout the build and it feels plenty strong, but around the firewall I'm going to add a few small gussets just to be safe. There were a few small mistakes along the way getting this far, but all will be hidden by covering material.

This build is supposed to be 1/4 scale, so I did a side-by-side with one of my 1/4 scale Cubs. Is the full-size Pete really that much smaller than a Cub?? Figure about 6" of engine and cowl in front of the firewall, still to be added.
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May 01, 2016, 02:59 PM
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According to the specs on the 3 view I have from the magazine, the full-scale span was 28' 2". Length was 17' 8" and wing area is 140 sq ft. The chord is not called out, but according to the scale shown is 5' even, as close as I can tell by eye. I have seen the full-scale built with many different power plants over the years, and the nose moment changes with the engine's weight. I don't know what a cast iron Model A engine weighs, but I guess it is a lot more than something like an aluminum Lycoming. Dave
Last edited by d wulff; May 01, 2016 at 03:06 PM.
May 01, 2016, 03:40 PM
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epoxyearl's Avatar
...and a Cub is just short of a 36 foot wingspan, and about 22 ' overall length.
Figure a Pete is about 3/4 the size of a Cub...........
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May 01, 2016, 03:41 PM
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IAW Wiki:

Specifications (J3C-65 Cub)[edit]

Inside the cockpit of a Piper Cub. The aircraft has far fewer instruments than most modern aircraft.
Data from The Piper Cub Story[36]
General characteristics

Crew: one pilot
Capacity: one passenger
Length: 22 ft 5 in (6.83 m)
Wingspan: 35 ft 3 in (10.74 m)
Height: 6 ft 8 in (2.03 m)
Wing area: 178.5 ft (16.58 m)
Empty weight: 765 lb (345 kg)
Useful load: 455 lb (205 kg)
Max. takeoff weight: 1,220 lb (550 kg)
Powerplant: 1 Continental A-65-8 air-cooled horizontally opposed four cylinder, 65 hp (48 kW) at 2,350 rpm



So, yes, the J-3 IS bigger!
May 02, 2016, 10:09 PM
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Landing gear testing, although these wheels are slightly too small. I've got to get some decent copper wire to wrap them well before doing the final soldering.
May 04, 2016, 07:41 PM
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Thanks Earl, this will be a fantastic addition to the build! Turns out this wood, which you said was glued up in 1937, was done the same year my dad was born, an interesting coincidence.
May 06, 2016, 11:29 PM
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Purty!
May 07, 2016, 06:11 PM
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I'm running out of work I can do on the fuselage without placing another order for wood, so attention has been turned to the wing. Making the work easier now, my dad dropped off a bandsaw and a disc sander which are INCREDIBLY helpful! The first thing I did was make a rip fence for the bandsaw so I could cut the old wood from a full size Pietenpole that EpoxyEarl sent me. A little sanding after the cuts and the pieces are done.

1/8" lite ply was cut to the shape of the wing ribs, and then all 3/32" stock I had was used to cut the ribs. Once a stack of 18 was ready I drilled a locating hole through the stack and stuck in a wood dowel to hold the pieces in alignment. Extra wood was trimmed and then sanded to final shape. It's amazing how much faster and more accurate the process is with that disc sander!

With a bunch of ribs done and ready I realized that I don't have enough 1/4" hardwood for the spars.. oops. Oh well, more wood is needed to finish the fuselage so I'll order up the additional pieces and can then get it all rolling again soon.
May 14, 2016, 11:22 AM
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The plans show a wing with removable sections which allows the wing to fit into smaller vehicles, but with a Ford Expedition that isn't much of a problem, so my plan is to go with a one-piece design. It will be constructed pretty close to the original design. Top/bottom sheeting and rib caps will be 1/16" balsa and ribs are 3/32" balsa. There are four spars which are 1/4" hardwood, and also 1/8" light ply spar webbing in the center portion of the wing.

After glue dries I'll make sure the wiring for aileron servos fits, cut holes for the wing spars, etc. Sheeting is being made from 3" wide 1/16" sheets glued together. Wider sheets would obviously give me fewer seams, but I have a bunch of the 3" sheets and would like to use some of them up.
May 15, 2016, 04:22 PM
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Winds were high and temps were low, so no flying this weekend, which gave me plenty of time to work on the Pietenpol. The wing's center section just needs top sheeting and the trailing edge.

A floor was also added in the nose for the gas tank, batteries, ignition, etc.

The pushrod tubes were run for both the elevator and rudder. I added some cross braces to support them, and then tied them in place with heavy sewing thread and then gave it a coat of epoxy to secure it all. It's not pretty, but it's not going anywhere!

This is about all I'll get to do on it for a couple weeks due to work travel and vacation time.
May 29, 2016, 10:00 PM
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Finally back from vacation and work travel, so it's time to get rolling again with the Peit! Admittedly I've been slacking on taking pictures of the wing construction, so here's where it is currently at:

The assembly is pretty straight forward. Bottom spars are pinned to the building board and ribs are placed as shown on the plans. Top spars are then installed, followed by the leading and trailing edges. The aileron pocket is also built up as shown in the plans. Each rib will be capped with 1/16" strips or full sheeting. Bottom caps are already installed in this picture.

Webbing is then glued in place between the top & bottom spar. This takes a little time, but gives considerable strength to the structure. It also shows me that I either need more clothespins or small clamps! In the morning I'll finish the webbing and start the structure for the servo and wing struts.
Jun 02, 2016, 06:57 PM
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The wingtips have some curve to them, and are made from 1/4" thick balsa sheet. I didn't have 1/4", but have 1/8" so that was used to my advantage. 4 pieces were cut (2 for each wing) and laminated together. The ends were propped up and a little weight was added to make the center sag while the glue cured. Clamps held it all together during the process.

The end result is some nicely curved balsa. In fact, it was curved a little TOO much and I had to coax it slightly flatter.

While that was going on, two attachment points were added flush with the bottom of the wing for the wing strut bolts. 1/8" light ply was used, and 4-40 captured nuts were added to the inside. This is very similar to how Sig did the mounts on my 1/4 scale Cubs, so I expect it'll work without problems. Note that the top of the leading edge is sheeted while the bottom is not, per plans.

Back to the wingtip, it's glued in place and bracing is added at the spar locations and leading/trailing edges. It got a little rough-sanding but I'll wait on final sanding until the wing is complete. This one only needs the aileron and servo mount to finish the rough-work, and I can then start on the starboard wing. It will also need a little filler in a few spots just to smooth it out, but overall I'm happy with how it's turning out. For old plans, these are much better than expected
Jun 03, 2016, 05:14 AM
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AA5BY's Avatar
Looking good.
Jun 03, 2016, 05:47 PM
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Quote:
Originally Posted by AA5BY
Looking good.

+1; makes me want to sell my started House of Balsa Pietenpol model and build this RCM plan version. I really like the construction used on this model.

Soft landings,

Joe
Jun 03, 2016, 06:41 PM
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Really?? What's wrong with the HoB kit? I've never looked at it before, is it the size or the construction?


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