Flitecraft J3 Cub ARF Repairs
11-05-2013, 01:11 PM
#1
Thread Starter
Flitecraft J3 Cub ARF Repairs
All of the posts related to Flitecraft from what I can tell are old, so I thought it best to start a new thread. Here are the more recent threads on these ARF aircraft:
http://www.rcuniverse.com/forum/club...rd-passes.html
http://www.rcuniverse.com/forum/arf-...older-arf.html
http://www.rcuniverse.com/forum/arf-...ightcraft.html
http://www.rcuniverse.com/forum/gold...ft#post4966781
I have a 58" (1,473mm) span Flitecraft J3 Cub ARF I purchased in the late 1990's. Partially assembled at the time, it was damaged during moving. The 1/4" (6mm) sheet foam rudder and stabilizer were damaged beyond repair. Now I am repairing it to flight readiness.
Out of 3/16" (5mm) Borden Poster foamboard, a matrix of thin glossy cardboard on both sides with a white foam in between, I have manufactured replacement tail flight surfaces. Once painted, this should be stiff enough to resist folding in flight. I've reused the plastic edge stiffeners. To make up for the thinner profile, I will be gluing 1/32" thick basswood sheet as shims in the glue contact areas of the fuselage, then Epoxy them in place.
The original wing bolts were 1/4" dia. steel, screwed into the 1/4" thick hardwood mount to cut threads. In a crash, most likely either the bolts would pull out or more likely the foam wing would fracture at the bolt location. I have drilled out the mount holes to Epoxy 1/4-20 blind nuts. Then I re-Epoxied the mount in place. I am using a Locktite 7-Min. Plastic Epoxy for these repairs involving the plastic fuselage. After repairs I will use nylon 1/4-20 screws for mounting the wing, not the steel ones.
Plane weighs 5.25 lbs (1 kg) with the OS .40FP mounted and 4 servos. By the time I paint, mount fuel tank, radio receiver and battery, tail wheel and RC linkages, it should weigh 5.5 lbs or a touch more.
The manual has been lost for some time, but completing this plane is straight forward enough that I don't need it.
To complete the missing hardware on the landing gear understruts, I used 10-12 gauge electrical crimp connectors. A little cheezy, the manufacturer used short pieces of automotive rubber vacuum or window wash tubing for the bungee strut shock. Upon first sollid landing I sense these cosmetic pieces will fail. I may remove them before first flight. Also, installing the cosmetic wing struts is more trouble than it is worth. I'm going to fly it without these.
The OS Max .40FP was missing the prop washer, so I have improvised by taking small fender washers and redrilling the hole to fit. I have stacked 4 washers, two larger and two smaller, but in reality I really only need the two larger ones. With the three it resembles the original washer in thickness, so for now I won't change it.
http://www.rcuniverse.com/forum/club...rd-passes.html
http://www.rcuniverse.com/forum/arf-...older-arf.html
http://www.rcuniverse.com/forum/arf-...ightcraft.html
http://www.rcuniverse.com/forum/gold...ft#post4966781
I have a 58" (1,473mm) span Flitecraft J3 Cub ARF I purchased in the late 1990's. Partially assembled at the time, it was damaged during moving. The 1/4" (6mm) sheet foam rudder and stabilizer were damaged beyond repair. Now I am repairing it to flight readiness.
Out of 3/16" (5mm) Borden Poster foamboard, a matrix of thin glossy cardboard on both sides with a white foam in between, I have manufactured replacement tail flight surfaces. Once painted, this should be stiff enough to resist folding in flight. I've reused the plastic edge stiffeners. To make up for the thinner profile, I will be gluing 1/32" thick basswood sheet as shims in the glue contact areas of the fuselage, then Epoxy them in place.
The original wing bolts were 1/4" dia. steel, screwed into the 1/4" thick hardwood mount to cut threads. In a crash, most likely either the bolts would pull out or more likely the foam wing would fracture at the bolt location. I have drilled out the mount holes to Epoxy 1/4-20 blind nuts. Then I re-Epoxied the mount in place. I am using a Locktite 7-Min. Plastic Epoxy for these repairs involving the plastic fuselage. After repairs I will use nylon 1/4-20 screws for mounting the wing, not the steel ones.
Plane weighs 5.25 lbs (1 kg) with the OS .40FP mounted and 4 servos. By the time I paint, mount fuel tank, radio receiver and battery, tail wheel and RC linkages, it should weigh 5.5 lbs or a touch more.
The manual has been lost for some time, but completing this plane is straight forward enough that I don't need it.
To complete the missing hardware on the landing gear understruts, I used 10-12 gauge electrical crimp connectors. A little cheezy, the manufacturer used short pieces of automotive rubber vacuum or window wash tubing for the bungee strut shock. Upon first sollid landing I sense these cosmetic pieces will fail. I may remove them before first flight. Also, installing the cosmetic wing struts is more trouble than it is worth. I'm going to fly it without these.
The OS Max .40FP was missing the prop washer, so I have improvised by taking small fender washers and redrilling the hole to fit. I have stacked 4 washers, two larger and two smaller, but in reality I really only need the two larger ones. With the three it resembles the original washer in thickness, so for now I won't change it.
Last edited by GallopingGhostler; 11-05-2013 at 01:15 PM.
11-05-2013, 09:07 PM
#2
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GG, Yes the solid landing gear fax bungees will not be good. I have successfully used the crimp electrical connectors but with elastic bungee material as the cross pieces. Buy some small elastic cords and replace the solid pieces you have in there now. When the dural landing flexes upon landing the bungee material will allow it move. Buy black cord if you can. Add a small piece of vacuum hose on each side to look like the bungee on a full scale. I have also put a piece of black shrink wrap over the vacuum hose and shrunk only the ends. Make the shrink wrap piece longer than the vacuum hose and when you shrink the ends it looks like the covers on the full scale. Also where the two cords cross one another add a small "O" ring that each cord passes thru. Cost next to nothing and looks good when done.
11-08-2013, 03:17 PM
#4
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Are you sure that your wing struts are cosmetic ? Many Cubs have functional struts and their wings will fail with out them . When you line up your gear put a little bit of toe in , in . It really helps .. The gear on a Cub is actually quite important because getting off the ground can be a challenge .. I don't know how much experience you have but by the sound of what you are doing you have a fair amount ..The prop washer is a tempered washer and I am not sure that I would want to use a regular soft washer is its place .. It would not be hard to get a replacement washer .. Any machine shop will have them or order one from OS if you want the factory replacement . The tapered front doesn't matter .. I have lots of motors that just have flat washers ..A soft washer might be okay for a day or two but keep a close eye on it ..
11-08-2013, 06:18 PM
#5
Thread Starter
bikerbc, I've attached a photo so you can see what the cabin strut is. It is basically the same flexible edging that is used in inexpensive photo poster frames. They are held in place with sheet metal screws instead of bolts through a nylon eyelet attached at both ends, one a plastic molded wing mount and the other the fuselage near the landing gear.. If they provide any structural strength, it is at best minimum. I don't see anything usual about this wing that doesn't seem atypical of Flitecraft other aircraft that did not have cabin struts.
However, I have read somewhere in recent research, that sometimes Flitecraft wings would fold in flight. For those into sheet foam or Corroplast (tm) wings, there is fold and fly. In the case of Flitecraft, perhaps fly and fold?
Your comments are taken seriously though, and I plan to add cabine struts so there is at least some support for the wing. Regarding the prop washers, I've used this on other engines and it seems to work fine. In this case the 4 washer stack shouldn't deform excessively. Although of softer steel that is easier to drill, there is sufficient mass in the stack and thickness in each washer to hold.
I've got the stabilizer and rudder mount area shimmed on both sides with 1/32 in. thick basswood and now Epoxied into place. The surfaces seem somewhat flimsy, about what the 1/4" thick original foam surfaces were. Once paper sides are primed with water based acryllic enamel varnish, should stiffen up quite a bit.
However, I have read somewhere in recent research, that sometimes Flitecraft wings would fold in flight. For those into sheet foam or Corroplast (tm) wings, there is fold and fly. In the case of Flitecraft, perhaps fly and fold?
Your comments are taken seriously though, and I plan to add cabine struts so there is at least some support for the wing. Regarding the prop washers, I've used this on other engines and it seems to work fine. In this case the 4 washer stack shouldn't deform excessively. Although of softer steel that is easier to drill, there is sufficient mass in the stack and thickness in each washer to hold.
I've got the stabilizer and rudder mount area shimmed on both sides with 1/32 in. thick basswood and now Epoxied into place. The surfaces seem somewhat flimsy, about what the 1/4" thick original foam surfaces were. Once paper sides are primed with water based acryllic enamel varnish, should stiffen up quite a bit.
Last edited by GallopingGhostler; 11-08-2013 at 06:25 PM. Reason: Further clarification.
11-13-2013, 08:01 PM
#8
Thread Starter
Elevator and Rudder now hinged and glued in place along with tail wheel assembly. Just need to install servos, fuel tank, linkages and paint the tail surfaces, we're almost home. I can now run around the house holding the airplane up while making glow motor noises with my mouth.
11-07-2015, 07:20 PM
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I really like your build article. I was wondering if you can help me. I have a Flitecraft J-3 Cub but I am missing the tail feathers. Would you have to have a trace of the ones you used on your airplane?
thanks Alan
thanks Alan
All of the posts related to Flitecraft from what I can tell are old, so I thought it best to start a new thread. Here are the more recent threads on these ARF aircraft:
http://www.rcuniverse.com/forum/club...rd-passes.html
http://www.rcuniverse.com/forum/arf-...older-arf.html
http://www.rcuniverse.com/forum/arf-...ightcraft.html
http://www.rcuniverse.com/forum/gold...ft#post4966781
I have a 58" (1,473mm) span Flitecraft J3 Cub ARF I purchased in the late 1990's. Partially assembled at the time, it was damaged during moving. The 1/4" (6mm) sheet foam rudder and stabilizer were damaged beyond repair. Now I am repairing it to flight readiness.
Out of 3/16" (5mm) Borden Poster foamboard, a matrix of thin glossy cardboard on both sides with a white foam in between, I have manufactured replacement tail flight surfaces. Once painted, this should be stiff enough to resist folding in flight. I've reused the plastic edge stiffeners. To make up for the thinner profile, I will be gluing 1/32" thick basswood sheet as shims in the glue contact areas of the fuselage, then Epoxy them in place.
The original wing bolts were 1/4" dia. steel, screwed into the 1/4" thick hardwood mount to cut threads. In a crash, most likely either the bolts would pull out or more likely the foam wing would fracture at the bolt location. I have drilled out the mount holes to Epoxy 1/4-20 blind nuts. Then I re-Epoxied the mount in place. I am using a Locktite 7-Min. Plastic Epoxy for these repairs involving the plastic fuselage. After repairs I will use nylon 1/4-20 screws for mounting the wing, not the steel ones.
Plane weighs 5.25 lbs (1 kg) with the OS .40FP mounted and 4 servos. By the time I paint, mount fuel tank, radio receiver and battery, tail wheel and RC linkages, it should weigh 5.5 lbs or a touch more.
The manual has been lost for some time, but completing this plane is straight forward enough that I don't need it.
To complete the missing hardware on the landing gear understruts, I used 10-12 gauge electrical crimp connectors. A little cheezy, the manufacturer used short pieces of automotive rubber vacuum or window wash tubing for the bungee strut shock. Upon first sollid landing I sense these cosmetic pieces will fail. I may remove them before first flight. Also, installing the cosmetic wing struts is more trouble than it is worth. I'm going to fly it without these.
The OS Max .40FP was missing the prop washer, so I have improvised by taking small fender washers and redrilling the hole to fit. I have stacked 4 washers, two larger and two smaller, but in reality I really only need the two larger ones. With the three it resembles the original washer in thickness, so for now I won't change it.
http://www.rcuniverse.com/forum/club...rd-passes.html
http://www.rcuniverse.com/forum/arf-...older-arf.html
http://www.rcuniverse.com/forum/arf-...ightcraft.html
http://www.rcuniverse.com/forum/gold...ft#post4966781
I have a 58" (1,473mm) span Flitecraft J3 Cub ARF I purchased in the late 1990's. Partially assembled at the time, it was damaged during moving. The 1/4" (6mm) sheet foam rudder and stabilizer were damaged beyond repair. Now I am repairing it to flight readiness.
Out of 3/16" (5mm) Borden Poster foamboard, a matrix of thin glossy cardboard on both sides with a white foam in between, I have manufactured replacement tail flight surfaces. Once painted, this should be stiff enough to resist folding in flight. I've reused the plastic edge stiffeners. To make up for the thinner profile, I will be gluing 1/32" thick basswood sheet as shims in the glue contact areas of the fuselage, then Epoxy them in place.
The original wing bolts were 1/4" dia. steel, screwed into the 1/4" thick hardwood mount to cut threads. In a crash, most likely either the bolts would pull out or more likely the foam wing would fracture at the bolt location. I have drilled out the mount holes to Epoxy 1/4-20 blind nuts. Then I re-Epoxied the mount in place. I am using a Locktite 7-Min. Plastic Epoxy for these repairs involving the plastic fuselage. After repairs I will use nylon 1/4-20 screws for mounting the wing, not the steel ones.
Plane weighs 5.25 lbs (1 kg) with the OS .40FP mounted and 4 servos. By the time I paint, mount fuel tank, radio receiver and battery, tail wheel and RC linkages, it should weigh 5.5 lbs or a touch more.
The manual has been lost for some time, but completing this plane is straight forward enough that I don't need it.
To complete the missing hardware on the landing gear understruts, I used 10-12 gauge electrical crimp connectors. A little cheezy, the manufacturer used short pieces of automotive rubber vacuum or window wash tubing for the bungee strut shock. Upon first sollid landing I sense these cosmetic pieces will fail. I may remove them before first flight. Also, installing the cosmetic wing struts is more trouble than it is worth. I'm going to fly it without these.
The OS Max .40FP was missing the prop washer, so I have improvised by taking small fender washers and redrilling the hole to fit. I have stacked 4 washers, two larger and two smaller, but in reality I really only need the two larger ones. With the three it resembles the original washer in thickness, so for now I won't change it.
