GSNadmin
Staff member
Now that the fuselage is almost completely built up, it’s time to start sheeting the structure and to begin some of the hardware installation. By first applying the 1/8-inch balsa sheeting to a few key areas, the fuselage structure becomes much more ridged and this helps it remain straight and properly aligned while moving it off of its supports.
The best place I think to start the sheeting is at the top, front section around the cockpit area. These are medium grain 4 inch wide sheets and they go on easily as there is very little compound curves here. I placed the sheets and drew guide lines on the framework and stringers. I then applied TiteBond yellow glue and pinned each sheet in place. Before applying the next sheet, check the fit of the mating edges. If there is a gap, sand the edge to match the edge of the glued sheet.
You can make the cockpit open as I have done here, or simply add the cockpit floor and use a pilot bust like one from Williams Bros.
Here is the cockpit floor (CF) part. If you go this way, you will have to sand the sides flush with the formers before sheeting the sides.
Here I test fitted the Sig Mfg., 13-inch WW2 Bubble canopy in place. It has a perfect profile and matches the plans exactly. I will have to check the width to make sure I can use it, but there is also a 15-inch canopy available if needed. It can be easily cut down in length.
After the forward part of the fuselage has been sheeted move to the vertical fin area. Here I am applying the first part of the sheeting. it is cut to fit the area shown and ends at the top rib, the leading edge, the aft rudder post and the center of the angled fin former.
After the first side is sheeted, let the glue dry, check the alignment to make sure the fin remains vertically straight and then apply the second side sheeting. Here it is being marked so I can cut it to size before pinning and gluing it in place.
I call this section of the tail sheeting the keel piece and it is fairly easy to glue in place as the forward edge only has a slight radius. Once both sides have been applied and the glue has dried, I used some putty to close up some of the seams. Once sanded smooth, the putty is all but invisible as are the seams.
The section of sheeting between the heel and the forward top sheeting was the most troublesome. As you can see, each side of the sheeting has a serious twist. At the keel the sheeting is almost perfectly vertical while the front edge is curved in a horizontal plane, so that’s almost a 90 degree twist. It took several tries, and cracked sheets to get it right.
Even wetting the balsa with Windex and ammonia, the 1/8-inch sheeting would keep cracking. The trick as it turns out is to cheat and apply two layers of 1/16-inch balsa sheeting. The first layer has a seam running along the top centerline along the top stringer, and the second layer is applied in three wedge-shaped pieces. The top center piece is pointed (1/2-inch wide), at the aft edge and is about 3 inches wide at the forward edge. Then the two side pieces are applied as shown. This helps spread the stress and prevents the seams from being placed on top of each other.
After the top has been sheeted, I installed the bottom aft section of the fuselage. This wedge shaped piece is made of 3/8-inch thick balsa and forms the base of the functional tail hook I am installing.
I made a simple removable tray from 1/8-inch lite ply and attached the tail hook mechanism to it so I can remove it if needed later on. When activated, the hook can lower to an 60 degree angle.
I installed a Hitec HS-125MG wing servo in the tail, aft of the tail hook mechanism. A short metal pushrod connects the two. I did it this way as the scale tailwheel will be located in front of the mechanism and there is no clear path to the activation lever from the front.
The servo is screwed to a plywood tray that is glued to the top of the 3/8-inch bottom wedge piece. Should it become necessary to replace the servo, I will simply cut an opening into the side of the fuselage and then add a hatch cover to seal it back up.
Stay tuned, before completing the sheeting, I will start on the servos and tail surface control linkages as well as the tail wheel installations.
Model Airplane News - The #1 resource for RC plane and helicopter enthusiasts featuring news, videos, product releases and tech tips.
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The best place I think to start the sheeting is at the top, front section around the cockpit area. These are medium grain 4 inch wide sheets and they go on easily as there is very little compound curves here. I placed the sheets and drew guide lines on the framework and stringers. I then applied TiteBond yellow glue and pinned each sheet in place. Before applying the next sheet, check the fit of the mating edges. If there is a gap, sand the edge to match the edge of the glued sheet.
You can make the cockpit open as I have done here, or simply add the cockpit floor and use a pilot bust like one from Williams Bros.
Here is the cockpit floor (CF) part. If you go this way, you will have to sand the sides flush with the formers before sheeting the sides.
Here I test fitted the Sig Mfg., 13-inch WW2 Bubble canopy in place. It has a perfect profile and matches the plans exactly. I will have to check the width to make sure I can use it, but there is also a 15-inch canopy available if needed. It can be easily cut down in length.
After the forward part of the fuselage has been sheeted move to the vertical fin area. Here I am applying the first part of the sheeting. it is cut to fit the area shown and ends at the top rib, the leading edge, the aft rudder post and the center of the angled fin former.
After the first side is sheeted, let the glue dry, check the alignment to make sure the fin remains vertically straight and then apply the second side sheeting. Here it is being marked so I can cut it to size before pinning and gluing it in place.
I call this section of the tail sheeting the keel piece and it is fairly easy to glue in place as the forward edge only has a slight radius. Once both sides have been applied and the glue has dried, I used some putty to close up some of the seams. Once sanded smooth, the putty is all but invisible as are the seams.
The section of sheeting between the heel and the forward top sheeting was the most troublesome. As you can see, each side of the sheeting has a serious twist. At the keel the sheeting is almost perfectly vertical while the front edge is curved in a horizontal plane, so that’s almost a 90 degree twist. It took several tries, and cracked sheets to get it right.
Even wetting the balsa with Windex and ammonia, the 1/8-inch sheeting would keep cracking. The trick as it turns out is to cheat and apply two layers of 1/16-inch balsa sheeting. The first layer has a seam running along the top centerline along the top stringer, and the second layer is applied in three wedge-shaped pieces. The top center piece is pointed (1/2-inch wide), at the aft edge and is about 3 inches wide at the forward edge. Then the two side pieces are applied as shown. This helps spread the stress and prevents the seams from being placed on top of each other.
After the top has been sheeted, I installed the bottom aft section of the fuselage. This wedge shaped piece is made of 3/8-inch thick balsa and forms the base of the functional tail hook I am installing.
I made a simple removable tray from 1/8-inch lite ply and attached the tail hook mechanism to it so I can remove it if needed later on. When activated, the hook can lower to an 60 degree angle.
I installed a Hitec HS-125MG wing servo in the tail, aft of the tail hook mechanism. A short metal pushrod connects the two. I did it this way as the scale tailwheel will be located in front of the mechanism and there is no clear path to the activation lever from the front.
The servo is screwed to a plywood tray that is glued to the top of the 3/8-inch bottom wedge piece. Should it become necessary to replace the servo, I will simply cut an opening into the side of the fuselage and then add a hatch cover to seal it back up.
Stay tuned, before completing the sheeting, I will start on the servos and tail surface control linkages as well as the tail wheel installations.
Model Airplane News - The #1 resource for RC plane and helicopter enthusiasts featuring news, videos, product releases and tech tips.
Continue reading...
