1/3 J-3 Overhaul
11-25-2014, 11:15 PM
#1
Thread Starter
1/3 J-3 Overhaul
Hi Guys,
I have an AMR kit built J-3 Cub. I have flown this plane for several years and it is a delight to fly. Unfortunately this spring I had a shelf fall in my trailer due to a poor installation by yours truly and broke the fin and rudder. The structural damage is minimal. I am going to do a complete re-covering job while I am at it. I initially covered the plane with Solartex. I was unhappy with the covering job from day one. It was too transparent for my taste. I have already stripped the fuse and tail feathers and I was really disappointed by how easily the Solartex tore and pulled lose from the structure. In my opinion it does not add any strength to the airframe at all. Not trying to offend anyone this is just my opinion.
I will be covering the Cub with Poly-Fiber lite uncertified fabric and finishing it with the Stits process. I will also be replacing the YDA-56cc engine with a DL-50cc engine. The YDA has been a nightmare to start and I am tired of fooling with it. Kind of takes the fun out of flying.
I will also be adding rib stitching, rib and reinforcement tapes. I have the broken rudder and fin already repaired. I should have the plane ready for covering by this Friday and I will start the covering process and will post updates as I go. This will be my first experience with the Stits process. I have done many fabric covering jobs using nitrate dope and polycrylic.
I am attaching a pic of the Cub when 1st built. We shall see how the re-finish compares.
Later!!
Anthony
I have an AMR kit built J-3 Cub. I have flown this plane for several years and it is a delight to fly. Unfortunately this spring I had a shelf fall in my trailer due to a poor installation by yours truly and broke the fin and rudder. The structural damage is minimal. I am going to do a complete re-covering job while I am at it. I initially covered the plane with Solartex. I was unhappy with the covering job from day one. It was too transparent for my taste. I have already stripped the fuse and tail feathers and I was really disappointed by how easily the Solartex tore and pulled lose from the structure. In my opinion it does not add any strength to the airframe at all. Not trying to offend anyone this is just my opinion.
I will be covering the Cub with Poly-Fiber lite uncertified fabric and finishing it with the Stits process. I will also be replacing the YDA-56cc engine with a DL-50cc engine. The YDA has been a nightmare to start and I am tired of fooling with it. Kind of takes the fun out of flying.
I will also be adding rib stitching, rib and reinforcement tapes. I have the broken rudder and fin already repaired. I should have the plane ready for covering by this Friday and I will start the covering process and will post updates as I go. This will be my first experience with the Stits process. I have done many fabric covering jobs using nitrate dope and polycrylic.
I am attaching a pic of the Cub when 1st built. We shall see how the re-finish compares.
Later!!
Anthony
11-27-2014, 07:50 AM
#6
Thread Starter
Happy Thanksgiving everyone,
I now have the plane all stripped with the exception of the struts, the repairs have been completed and the Robart hinges drilled out. I had purchased a wrap around muffler for the DL-50 for the Cub but have found that I would still need to cut away the side of the new cowl for clearance and would have to make major modifications to the firewall. Pretty much a deal killer for the wrap around muffler. If I was buying a new engine I would get a DLE-55 rear exhaust and fix the issue. Just not something I want to do for this plane.
I have enough fabric on hand to cover the Cub, I will start applying fabric tomorrow. I need to place an order tomorrow for the Poly-Brush, Poly-Spray, Poytone (color coat) and rib tapes. If all goes well I will get the plane covered this weekend and start applying the tapes next weekend.
I will post some pics tomorrow when the fabric starts going down.
Later!
Anthony
I now have the plane all stripped with the exception of the struts, the repairs have been completed and the Robart hinges drilled out. I had purchased a wrap around muffler for the DL-50 for the Cub but have found that I would still need to cut away the side of the new cowl for clearance and would have to make major modifications to the firewall. Pretty much a deal killer for the wrap around muffler. If I was buying a new engine I would get a DLE-55 rear exhaust and fix the issue. Just not something I want to do for this plane.
I have enough fabric on hand to cover the Cub, I will start applying fabric tomorrow. I need to place an order tomorrow for the Poly-Brush, Poly-Spray, Poytone (color coat) and rib tapes. If all goes well I will get the plane covered this weekend and start applying the tapes next weekend.
I will post some pics tomorrow when the fabric starts going down.
Later!
Anthony
11-27-2014, 05:10 PM
#8
Thread Starter
I did apply fabric to the firewall before I left for the family gathering today. Covering will begin in earnest in the morning.
Later!!
Anthony
11-28-2014, 06:43 AM
#10
Thread Starter
Finally ready to start putting fabric down.
I am going to start on the fuse as it will be the most involved, get that part out of the way 1st. I have a rotating mount that I used for covering and painting that works quite well. Makes the job a bit easier. I will be attaching the fabric with Nitrate dope. I have better than a quart on hand so might as well use it.
I will start by covering the stabs and the bottom of the fuse. Going to be a long day.
One thing I recently added to my hobby room is a peg board, I don't know how many times I bought new hardware because I could not find what I knew I had. I was surprised to fin out how much stuff I was able to throw up on the board as I started cleaning up the room.
Later!!
Anthony
I am going to start on the fuse as it will be the most involved, get that part out of the way 1st. I have a rotating mount that I used for covering and painting that works quite well. Makes the job a bit easier. I will be attaching the fabric with Nitrate dope. I have better than a quart on hand so might as well use it.
I will start by covering the stabs and the bottom of the fuse. Going to be a long day.
One thing I recently added to my hobby room is a peg board, I don't know how many times I bought new hardware because I could not find what I knew I had. I was surprised to fin out how much stuff I was able to throw up on the board as I started cleaning up the room.
Later!!
Anthony
11-28-2014, 08:49 AM
#12
Thread Starter
The bottom of the stabs and the fuselage have been covered,
For those who have not tried a fabric covering job it is not as difficult as it may appear. There are also some major advantages to it as far as strength goes. I start by brushing 2 coats of Nitrate dope along the perimeter of the structure where I want the fabric to adhere, when dry give it a light sanding with 400 grit paper. Cut the fabric 1-2" oversized and lay over the structure then brush nitrade dope thru the fabric. The fabric will become translucent when properly wetted out and you should see the grain of the wood thru the fabric. This assures the dope has been activated underneath and a good adhesion will occur upon drying. I brush dope about 1/2" into the overhang and then trim once dried. This keeps the fabric from fraying. Once trimmed then the edge gets doped down smooth.
The fabric will get shrunk with an iron once all the sides have been applied. You have to be very carful not to shrink the fabric before all the sides are covered. If you soften an edge with more dope after shrinking it will pull loose. Also this fabric is very strong, it is more than capable of warping and even crushing the structure if over shrunk. Unlike iron on coverings once you shrink and finish the fabric is will stay tight. It will not slacken with temperature changes like iron on coverings.
Here are a few pics of the bottom covering going down.
For those who have not tried a fabric covering job it is not as difficult as it may appear. There are also some major advantages to it as far as strength goes. I start by brushing 2 coats of Nitrate dope along the perimeter of the structure where I want the fabric to adhere, when dry give it a light sanding with 400 grit paper. Cut the fabric 1-2" oversized and lay over the structure then brush nitrade dope thru the fabric. The fabric will become translucent when properly wetted out and you should see the grain of the wood thru the fabric. This assures the dope has been activated underneath and a good adhesion will occur upon drying. I brush dope about 1/2" into the overhang and then trim once dried. This keeps the fabric from fraying. Once trimmed then the edge gets doped down smooth.
The fabric will get shrunk with an iron once all the sides have been applied. You have to be very carful not to shrink the fabric before all the sides are covered. If you soften an edge with more dope after shrinking it will pull loose. Also this fabric is very strong, it is more than capable of warping and even crushing the structure if over shrunk. Unlike iron on coverings once you shrink and finish the fabric is will stay tight. It will not slacken with temperature changes like iron on coverings.
Here are a few pics of the bottom covering going down.
11-28-2014, 09:05 AM
#13
Looking real Good Anthony. I really love fabric covering. My very first rc plane was silk and dope. I already had plenty of silkspan (tissue) and dope covering under my belt from control line.
The plane in my avatar is polyester dress lining. Not much heat shrink in the material so nitrate dope was used to shrink it. It shrunk up drum tight. Then rattle canned.
I will do small planes with plastic film, but I really like fabric for my bigger planes and planes that I am hoping to keep till I pass on.
Ken
The plane in my avatar is polyester dress lining. Not much heat shrink in the material so nitrate dope was used to shrink it. It shrunk up drum tight. Then rattle canned.
I will do small planes with plastic film, but I really like fabric for my bigger planes and planes that I am hoping to keep till I pass on.
Ken
11-28-2014, 09:50 AM
#15
Thread Starter
Hi Ken,
Most of my planes are fabric covered. I originally built the Cub for a product review in Fly R/C magazine and I was under a deadline to have the plane built, flown and the article written in 2 months. I decided to take a shortcut and apply the Solartex. The plane looked good when finished but I never was happy with the covering job. This plane fly's so well it deserved a new proper covering job.
Later!!
Anthony
Most of my planes are fabric covered. I originally built the Cub for a product review in Fly R/C magazine and I was under a deadline to have the plane built, flown and the article written in 2 months. I decided to take a shortcut and apply the Solartex. The plane looked good when finished but I never was happy with the covering job. This plane fly's so well it deserved a new proper covering job.
Later!!
Anthony
11-28-2014, 12:30 PM
#16
Thread Starter
I have the fabric on the right side of the fuselage.
A J-3 fuselage can be tough to cover. The covering forms the fillet at the fin and in order to get it correct you need to cover one side of the fuse and fin at the same time as well as 1/2 of the top. Once I get the other side on then apply the fabric to the top of the center section I can shrink it up and see how it looks.
A J-3 fuselage can be tough to cover. The covering forms the fillet at the fin and in order to get it correct you need to cover one side of the fuse and fin at the same time as well as 1/2 of the top. Once I get the other side on then apply the fabric to the top of the center section I can shrink it up and see how it looks.
11-28-2014, 01:38 PM
#17
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And for those that have never used raw fabric and probably not use to seeing such wrinkle's, don't fret. The fabric will shrink up to 12% which is more than enough to remove the wrinkles and break the fuse in half if heated enough. Look's fantastic Anthony!
Sorry buddy, I think I just repeated what you said earlier.
Sorry buddy, I think I just repeated what you said earlier.
11-28-2014, 01:48 PM
#18
Thread Starter
Yeah this fabric makes me look good
The left side is coming along, just need to secure along the top of the turtle deck and the fin. Once the fabric is shrunk I will secure the fabric around the windows and then cut them out. A lot of trimming and sealing to do.
Later!!
Anthony
The left side is coming along, just need to secure along the top of the turtle deck and the fin. Once the fabric is shrunk I will secure the fabric around the windows and then cut them out. A lot of trimming and sealing to do.
Later!!
Anthony
11-28-2014, 04:02 PM
#19
Thread Starter
All the covering is now on the fuse and it has the initial shrink completed. I gave it a shrink at 240deg and will raise the iron temp to around 275 for the final shrink after the tapes are applied.
The fabric looks good, no wrinkles to deal with. I will dope around the windows and the door tomorrow then cut them out and seal the edges down. All the rest of the parts will be a breeze to cover compared to the fuselage.
Here are a couple pics of the fuse after shrinking the fabric.
later!!
Anthony
The fabric looks good, no wrinkles to deal with. I will dope around the windows and the door tomorrow then cut them out and seal the edges down. All the rest of the parts will be a breeze to cover compared to the fuselage.
Here are a couple pics of the fuse after shrinking the fabric.
later!!
Anthony
11-29-2014, 04:10 AM
#20
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It seems almost like a lost art covering models in fabric. I love the process where a bare frame gets that near done look once fabric is tightened. I actually have a lot of the Stits Poly Tone, Tac, Spray, in Cub yellow that I plan on selling. How does Fedex deal with materials like that, just label as hazardous?
11-29-2014, 04:32 AM
#21
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It seems almost like a lost art covering models in fabric. I love the process where a bare frame gets that near done look once fabric is tightened. I actually have a lot of the Stits Poly Tone, Tac, Spray, in Cub yellow that I plan on selling. How does Fedex deal with materials like that, just label as hazardous?
11-29-2014, 04:39 AM
#22
It seems almost like a lost art covering models in fabric. I love the process where a bare frame gets that near done look once fabric is tightened. I actually have a lot of the Stits Poly Tone, Tac, Spray, in Cub yellow that I plan on selling. How does Fedex deal with materials like that, just label as hazardous?
Sincerely, Richard
Cub Brotherhood #187; Sig 1/4, H9 100 inch (Gen 1), GB Anniv Cub
Club Saito #635; Saito 56, 100, 120abc, 130T, 180
Kadet Brotherhood #96; Mk 1 Kadet, Kadet Junior,
Sig Kougar, Sig 1/4 Cub, Sig 1/4 Spacewalker II
11-29-2014, 07:12 AM
#25
Thread Starter
Thanks ARUP,
Steve,
The dope puts off a lot of fumes, you need a well ventilated room for sure. I have a fan in the window drawing the fumes out and I run an electric heater in the room while I am doing the doping to help the fumes rise and exit the window. A respirator would probably be a good idea but I cannot handle wearing one for that long. While spraying I wear a respirator.
The windows and door have been cut out and sealed down. The fuse is now ready for the tapes and poly brush once I receive them. I will start working on the wings next.
Steve,
The dope puts off a lot of fumes, you need a well ventilated room for sure. I have a fan in the window drawing the fumes out and I run an electric heater in the room while I am doing the doping to help the fumes rise and exit the window. A respirator would probably be a good idea but I cannot handle wearing one for that long. While spraying I wear a respirator.
The windows and door have been cut out and sealed down. The fuse is now ready for the tapes and poly brush once I receive them. I will start working on the wings next.
