RC airplane plan Micro Pitts

Micro
Pitts Special for the RFFS-100 by Chris O’Riley
Small balsablocks for LGreinforcementF1F2F3F4Small balsablocks for LGreinforcementF1F2F3F4All wood 1/32 inch sheet unless otherwise stated.1234

F1F3F4(1/8)F2 (1/16)(1/8)

C1 (1/16)C2 (1/8)C3 (1/16)(1/8)

(1/8)

(1/8)
Before gluing in F2, create a small “J” hookfrom thin music wire, and attach it to F2with length of rubber band. There shouldbe 1/8 inch of rubber band between F2and the hook. This will be used to securethe battery in the cowl. When gluing inF2, angle it to provide 6° of right and 3°of down thrust. This may seem like a large amount of right thrust,but it’s necessary due to the short tail and small vertical stabilizer.Also, sand F2 as necessary to position it far enough forward so yourprop will clear the front of the cowl. Do this by removing themotor from a KP-00 and resting the gearbox on F2 as you positionit in the fuselage. Once positioned, you can pull the gearbox outand glue in F2.
At this time, assemble the cowl and wheel pants. Glue C1, C2 and
C3 together, then round the edges with sand paper, gently sloping
the lower front of the cowl. For the wheel pants, glue together the
two 1/8 center sections and taper each side until the rear is about
1/16 of an inch wide. Glue on the 1/32 sides and round the front
and top sides. If you’ll be using dye to color your model, keep the
glue away from edges that will be sanded round, as the dye will not
be absorbed into the glue. Alternatively, you can carve the wheel
pants and cowl from single pieces of 1/4 inch wood.
Sand the front of the fuselage to providea completely flat surface for the cowl tomate with, then glue the cowl on. Also,reinforce the bottom opening (directly infront of where the bottom wing will attach)with some string saturated with CA. Thewood is fairly stressed in this area, and couldsplit without this reinforcement.
Connect the two elevator halves with asmall 1/16 inch stick, then attach theelevator to the horizontal stabilizer withthin slivers of rubber band. Glue thehorizontal and vertical stabilizer to thefuselage, making sure they’re in alignment,then attach the rudder.
Construction notes:Use the lightest, thinnest 1/32 balsa for allwood except where indicated on the plans.
The best time to color the plane is before
assembly. Colored dye does an excellent
job at providing full color at a virtually
insignificant weight gain. Stripes can then
be added with paint or markers.The wings go together quickly. Join thetop wings with a dihedral of 1/8 inch.Prepare the bottom wings with a dihedralof 5/8 inch, but don’t join them yet.
Start building the fuselage by gluing therear turtledeck - from the back of thecockpit to the slot for the vertical stabilizer.Glue the front upper deck next and, finally,the front lower cowl. Gluing the lowercowl is best accomplished by reaching infrom the front of the fuselage with your index fingers and holdingthe two halves together over a flat surface. In all cases, doing thisover waxed paper prevents the parts from sticking to your buildingsurface. Give these joints plenty of time to dry before proceeding.
Carefully glue in the fuselage former F1,making sure it’s straight and flush with thefront edge of the fuselage. Next, gluetogether the rear-most edges of the fuselagehalves together (where the rudder willeventually attach). Finally, glue in formersF3 and F4, paying attention to minimizing any uneven bowing ofeither bottom edge of the fuselage. Some bowing will occur, justtry to keep it even between the two sides.
Attach the bottom wings by carefully slidingthem through the slots in the fuselage andgluing them together. Once together,position and align the wings within thefuselage and glue with a small drop of CAon the leading and trailing edges on theinside of the fuselage.
Attach the top wing by first gluing theinterplane struts. These struts will set thecorrect position of the top wing, and youcan then glue in the cabane struts, madefrom 1/16 inch sticks sanded round. Usethe cabane struts to make sure the incidenceangle remains constant across the top wing.
At this time, glue in the small reinforcement blocks for the landing
gear where indicated on the plan, then sheet the bottom of the
fuselage with an oversized piece of 1/32 balsa. If you have any
uneven bowing in the bottom of the fuselage, glue the bottom sheet
a little at a time, gently removing the bowing as best as possible.
Once glued, carefully trim the bottom sheet and lightly sand the
edges. If you’re coloring the plane, dye this bottom sheet before
attaching, and then color the edges after trimming with marker.
Build the landing gear from small diametermusic wire. Each side is made from twoseparate pieces, as shown in the diagrambelow. Predrill small holes through thereinforcement blocks, and test fit the landinggear. Connect the two pieces of each side,held in place in the fuselage, by wrapping with thread and saturatingwith CA, or by wrapping with a single strand of copper wire andtinning with solder. Next, glue each side into the reinforcementblocks and, finally, attach the rear struts together where they crosswith either thread and CA or copper wire and solder. Glue on thebalsa landing gear struts and then the wheels and wheel pants.
Construction notes:

Add the components in the standard
manner. I use rubber cement to attach the

coils so they can be easily removed if
necessary. The coil wires may be passed
through the openings on either side of the
rudder and the space for the elevator joinerto travel. As shown in the picture, slide the battery up into the cowluntil it hits former F1. Secure the battery by reaching in throughthe bottom opening with a pair of tweezers to grab the “J” hook.Place the RFFS-100 horizontally in thecenter of the cockpit. I gently pressed itinto the bottom wing until the posts beneaththe battery and motor connectors penetratedthe wing. This keeps the board from slidingforward or back, and holding it down witha finger as you remove the battery leadskeeps it from being pulled up. I use a length of thin coated copperwire for the antenna, which is passed to the rear of the fuselage andexits through a small hole in the bottom sheeting.
Built as shown, the plane should balance where indicated on the
plan. If needed, a penny or two may be placed in the nose, beneath
the battery to bring the CG forward. Double check your controls
and your MicroPitts should be ready to fly.
On this page, I’ve also included outlines for analternate set of bottom wings, interplane strutsand a solid rudder, should you want to useailerons. If you choose this, you’ll have torelocate the battery into the cockpit tocompensate for the decreased weight on thetail. You might also want to remove alldihedral from the top wing and decrease itin the bottom wing to somewhere between1/4 to 3/8 inch. Doing so will necessitatethe use of the alternate struts to maintain theheight of the top wing. When gluing the ribs tothe wings, simply trim and discard the excess fromthe back - there’s no need to add ribs to the ailerons.


RC airplane plan Micro Pitts

PDF file: http://www.chris3d.com/files/micropitts.pdf