Go Back  RCU Forums > RC Airplanes > Kit Building
Reload this Page >

Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Notices
Kit Building If you're building a kit and have questions or want to discuss kit building post it here.

Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Old 07-20-2011, 06:21 PM
  #176  
Zor
Banned
 
Join Date: Feb 2009
Location: Ontario, ON, CANADA
Posts: 3,524
Likes: 0
Received 1 Like on 1 Post
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)


Thanks SunDevilPilot.

Zor
Old 07-22-2011, 03:00 PM
  #177  
roncannell
Senior Member
 
Join Date: Dec 2005
Location: Chandler, AZ
Posts: 577
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Phil, It looks great, and I like the STOL look for your tires.
Ron
Old 07-30-2011, 07:07 PM
  #178  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I received all the wood I needed and have started building the left wing. No need for photos at this point as it looks just like the right wing.

The spruce spars from Aircraft Spruce are really nice quality, I will order from them again. The balsa from sig was a little less than perfect but decent enough.

So far I have the bottom sheeting, bottom spars, and the wing ribs assembled. After the lower assembly glue dries I will continue. For now it is weighted down.

SunDevilPilot
Old 07-31-2011, 03:34 PM
  #179  
cubcrasher
My Feedback: (6)
 
Join Date: Jun 2011
Location: Locust, NC
Posts: 486
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Sundevil,
I've built a lot of cubs over the years and can tell you that you will be very pleased with the sig 1/4 scale, best one around.
You & Waco Nut do top notch work
Old 07-31-2011, 05:19 PM
  #180  
SkyPilot101
Senior Member
 
Join Date: Jun 2007
Location: Freedom, PA
Posts: 574
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I am really looking forward to seeing this build head toward compleation and flight! I know where to lay my hands on either the Sig or Balsa USA 1/4 Cub kits, and would love to do a PA-18 conversion. What do you guy's think would be the better choice for this build? Right know I'm leaning toward the Sig.
Old 07-31-2011, 06:54 PM
  #181  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I have been really happy with the Sig kit but I have been wanting to build something from Balsa USA, possible a WWI bi-plane. I have ordered wood from them before and it was really nice stuff.

I picked the Sig based on my past experience with their stuff and because i had seen many of their 1/4 Cubs over the years. In my little circle the Sig is the benchmark for a 1/4 Cub.

I don't think you can go wrong with either.

Below is a photo of the wing in its current state. I need to cut the sheer webs, which can be done easily and perfectly on the table saw.... However, there is a monsoon storm outside so cutting them will have to wait until tomorrow afternoon. Monday morning is for going flying!

(Some may see the mess, which is rare around my castle!)

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Tr49884.jpg
Views:	263
Size:	151.6 KB
ID:	1642696  
Old 07-31-2011, 07:49 PM
  #182  
TripleDeucer
My Feedback: (129)
 
TripleDeucer's Avatar
 
Join Date: Feb 2002
Location: College Place, WA
Posts: 527
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I'm presently working on a 1/3 BUSA Super Cub. It's a great kit and is going together good as I have time. No real deadline to meet. I do prefer the way Sig marks the pieces of wood, whereas BUSA does not and you have to study the plans and book more to understand what goes where. Both enjoyable kits.
Old 07-31-2011, 07:58 PM
  #183  
SkyPilot101
Senior Member
 
Join Date: Jun 2007
Location: Freedom, PA
Posts: 574
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Oh,oH I think I might have to drive up to LHS at lunch and pick up the Sig, they had a 4*120 TOO! ....... Great Build SD Pilot.
Old 07-31-2011, 08:00 PM
  #184  
TripleDeucer
My Feedback: (129)
 
TripleDeucer's Avatar
 
Join Date: Feb 2002
Location: College Place, WA
Posts: 527
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Oh yeah, you gotta get them when you see them. Kinda hard to find.
Old 08-01-2011, 08:13 PM
  #185  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Shear webs installed. Tomorrow I will build the pocket for the main spar.

SunDevilPilot
Old 08-01-2011, 10:20 PM
  #186  
roncannell
Senior Member
 
Join Date: Dec 2005
Location: Chandler, AZ
Posts: 577
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Phil,the BUSA Fokker D-7 gets great reviews, comes in 1/4 and 1/3 scale. Its a heavy sucker though. Or you could build a DR1 and join the Jasta. The new DR1 is comming along.
Attached Thumbnails Click image for larger version

Name:	Us55077.jpg
Views:	125
Size:	65.3 KB
ID:	1643314   Click image for larger version

Name:	Zx71091.jpg
Views:	125
Size:	45.0 KB
ID:	1643315  
Old 08-06-2011, 02:08 PM
  #187  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I now have two wings that are free from the building board. Both came out nice and straight. Next step is to install the hard points for the struts then add the wingtips. Once that is done the control surfaces (Ailerons and flaps) will be removed, completed, and hinged. At that point most of the construction of the components will be complete. It will be a matter of putting the tail surfaces on and then onto servo installation. Getting closer!

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Yw67559.jpg
Views:	248
Size:	176.0 KB
ID:	1645146   Click image for larger version

Name:	Zu66367.jpg
Views:	255
Size:	131.4 KB
ID:	1645147  
Old 08-06-2011, 03:07 PM
  #188  
cubcrasher
My Feedback: (6)
 
Join Date: Jun 2011
Location: Locust, NC
Posts: 486
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Not as many sticks in that box as there once was hey sundevil.
Man I don't care what nobody says that is a lot of building.
The finished product will be well worth it.
Old 08-06-2011, 04:01 PM
  #189  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I am glad to see the big box of sticks finally starting to thin out. I am also glad to see the wings mount up as planned despite all the modifications I made to the fuselage. Everything is coming together!

SunDevilPilot
Old 08-07-2011, 03:03 PM
  #190  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

I really didn't want to install the jury strut mounts, I was afraid to cut into my nicely sheeted wing to inlay the mounts, but I forged ahead. You have to notch the sheeting at the spar. The process was not that bad once I got started. I clamped the mount to the wing, went around a few times with a sharp xacto knife, then cleaned out the balsa using my dremel with a router base attached. The dremel router make it easy to clean off the spar of the balsa sheeting and associated glue.

I did modify the jury strut mounts in that I added a 1/4" spacer and an additional piece of ply to "Capture" the spars within the mount. The plans call for a single piece of ply to be glued to the spars and that's it. Sure, it is just the jury strut mount but I don't want to risk a failure given the fact the struts are functional (AKA Required) to keep the wings from folding. The mounts use 4-40 bolts and blind nuts epoxied to the rear. The bolts will also hold the mounts together and keep the spar captured.

The mount for the actual struts are next and are built just like the jury strut mounts.

The mounts have yet to be sanded so there is a little excess glue, which is perfect.

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Ig12336.jpg
Views:	298
Size:	110.4 KB
ID:	1645712   Click image for larger version

Name:	So42736.jpg
Views:	310
Size:	122.1 KB
ID:	1645713  
Old 08-07-2011, 08:30 PM
  #191  
do335a
 
Join Date: Mar 2006
Location: Toronto, ON, CANADA
Posts: 636
Likes: 0
Received 7 Likes on 4 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

When I did mine, on the clipped wing version, I cut the holes in the sheeting before I glued it to the wing frame. It seemed a bit odd to me to do it in the suggested sequence.

As for their functionality, they never let go and neither did the mounts, no matter how many Gs I pulled with that plane. I did ultimately experience the same condition which others found. The brass tubes cracked at the bends where they are flattened.
Old 08-08-2011, 05:12 AM
  #192  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

ORIGINAL: do335a

When I did mine, on the clipped wing version, I cut the holes in the sheeting before I glued it to the wing frame. It seemed a bit odd to me to do it in the suggested sequence.

As for their functionality, they never let go and neither did the mounts, no matter how many Gs I pulled with that plane. I did ultimately experience the same condition which others found. The brass tubes cracked at the bends where they are flattened.
Your method would definately save a lot of time and effort. It is somewhat strange how they have you cut away the sheeting after it was done. Removing the wood and the glue from the spar, without damaging the spar itself, is not the easiest of things to do.

While not quite scale I plan on changing the jury struts to some airfoiled aluminum, like shown below on my 1/5th scale cub. Hopefully that will last longer than the bent brass of the stock kit. I have a couple years of flights on the 1/5th scale and there is no sign of any issue. Like the 1/5th cub, this one will be electric so there will not be the damaging effects of engine vibration.

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Mk25532.jpg
Views:	360
Size:	58.9 KB
ID:	1645903  
Old 08-09-2011, 02:47 PM
  #193  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

All the mounts for the Struts / Jury Struts are complete. All mounts were built in a similar manner, ply plates overlapping the spars on both sides with a ply core in the middle. Each has a 4-40 blind nut epoxied into the back side. Should hold up well.

It is really starting to look like a Cub now!

Next up is the curved wingtips.

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Mk25503.jpg
Views:	300
Size:	148.8 KB
ID:	1646696   Click image for larger version

Name:	Bz78613.jpg
Views:	277
Size:	118.7 KB
ID:	1646697  
Old 08-09-2011, 08:15 PM
  #194  
d boothe
My Feedback: (16)
 
d boothe's Avatar
 
Join Date: Dec 2003
Location: fairhope , AL
Posts: 115
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Im building the clipped wing version and I have been following this tread, Its been a while since i did the wing/strut mount on mine but i remember it being odd in sequence following the manual. I have not flown mine yet but i have seen alot of the 1/4 scale cubs get tossed around without any problems with the stock setup sig recomends.
Old 08-09-2011, 11:23 PM
  #195  
AmishWarlord
My Feedback: (5)
 
AmishWarlord's Avatar
 
Join Date: Oct 2002
Location: Indian Trail, NC
Posts: 2,939
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Hey SDP, if your willing to give up a lot of efficiency, Hobby King has some very nice looking cherry laminated props with old style rounded tips. Shipping will cost more than the prop but it's still a good price. You just have to wait for them to get your size in stock before you order one.

http://www.hobbyking.com/hobbyking/s...idProduct=5765
Old 08-10-2011, 03:24 AM
  #196  
tommyhawk
Junior Member
 
Join Date: Aug 2007
Location: Cold Lake, AB, CANADA
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Nicely done, SDPilot. Glad to see you back at this one. My BUSA 1/3 Supercub is coming along (I have a thread on RCScalebuilder) and I'm toying with the idea of doing a 1/4 scale when I'm done so as to have an easier to transport PA18. I like your adaptation. Might have to steal some of your ideas...

Tom
Old 08-13-2011, 02:24 PM
  #197  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)


ORIGINAL: AmishWarlord

Hey SDP, if your willing to give up a lot of efficiency, Hobby King has some very nice looking cherry laminated props with old style rounded tips. Shipping will cost more than the prop but it's still a good price. You just have to wait for them to get your size in stock before you order one.

http://www.hobbyking.com/hobbyking/s...idProduct=5765
Those are some nice looking props. Thanks for the link. For this project I will stay with the Mejzlik Carbon Prop but I may consider those for something else.

SunDevilPilot
Old 08-13-2011, 02:29 PM
  #198  
SunDevilPilot
Thread Starter
 
SunDevilPilot's Avatar
 
Join Date: May 2002
Location: Gilbert, AZ
Posts: 2,025
Likes: 0
Received 3 Likes on 3 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Today I was able to get a good start on the wing tips. They went on without any major issues. I still need to laminate some balsa around the curve, add the leading edge stock, finish the wing tip sheeting, and carve it all to shape but I can almost see the end of the tunnel in terms of the major woodworking.

Is somewhat refreshing to just take the parts out of the box and put them on. It seems I have modified so much of this kit I plan each step spending about ten times as long as it should.

So far I'm really proud of my work.

SunDevilPilot
Attached Thumbnails Click image for larger version

Name:	Db86267.jpg
Views:	279
Size:	86.9 KB
ID:	1648400   Click image for larger version

Name:	Ni23166.jpg
Views:	252
Size:	91.7 KB
ID:	1648401  
Old 08-13-2011, 02:42 PM
  #199  
cubcrasher
My Feedback: (6)
 
Join Date: Jun 2011
Location: Locust, NC
Posts: 486
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

Man you ought to be.
You would be surprised of the guy's who would not even attempt to build this kit.
I always said that a sig 1/4 scale cub separates the men from the boys.
Old 08-13-2011, 02:57 PM
  #200  
AmishWarlord
My Feedback: (5)
 
AmishWarlord's Avatar
 
Join Date: Oct 2002
Location: Indian Trail, NC
Posts: 2,939
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)

That's some really nice wood those ribs are made of. Sig did a good job in balsa selection there. Was this a older kit or is this a new production one?


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.