HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 18, 2009, 01:11 PM
Suspended Account
Joined Jul 2006
22,991 Posts
Hi EJ,

Thanks for the detailed description of the gluing technique. While I'm nowhere near where you're at skill-wise, I'm really enjoying your fixture and jig work techniques. I've saved this thread into my "Tips and Techniques for working with Balsa" file and will try to work some of the methods into my own obsession with straightness.

I really truly appreciate all the detailed pics of your methods!

Chuck
NoFlyZone is offline Find More Posts by NoFlyZone
Reply With Quote  (Disabled)
Sign up now
to remove ads between posts
Old Jul 18, 2009, 02:54 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Hey Chuck,

I appreciate the kind words.

I get a lot of ideas and information from RCG, RCU, and other modeling forums. If I take away, it's an obligation to put something back in. Plus, it's a lot of fun watching it all go together!

As far as skills, well, what you DON'T see on the New Yankee Workshop is all the "do overs"... A big part of skill building is avoiding and minimizing mistakes. This doesn't mean that they are not going to happen. Heck, if I had a wood-burning stove in my shop, I'd be part of the blame for global warming!

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 18, 2009, 08:06 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Cabin frame pieces all in place. later on, plywood is laid over the top of the cabin frame for a more solid structure.

Since I had all the main components in the area, I couldn't resist putting them in place to get an idea of how things are shaping up...

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 19, 2009, 12:33 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
The rest of the aft fuselage formers are now glued into place.

Yes, I went through some acrobatics here when I could have just “hit” the formers with a little CA and been on my way. But, like I mentioned, for me, a lot of the fun is in cutting, shaping, glueing and clamping.

When glueing, depending on what type glue you’re using, time can be of the essence. One of the tricks to glueing is being as ready as possible to apply the clamps after you apply the glue to the joint. The best way that I have found to do this performing a “dry-fit” of the parts to be glued. Look at it as a dress rehearsal. You put all the pieces in place right down to clamping them together. This way you will catch any problems that you may not have time to deal with *IF* the pieces had glue on them. You get to adjust the clamps to the approximate openings. You get to see if you need additional clamps. You see how any jigs you have arranged are going to react under clamping pressure. Best of all, when you remove the clamps and jigs for the dry-fit, you’ll have all the tools and items you need right in front of you.

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 19, 2009, 12:48 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Another look at the aft fuselage formers all in place. I cut lightning holes in all but the last two, which support the horizontal stab.

Forward top fuselage stringers are now in place.

This model, like the typical open “stick” construction build, involves many joints in which the wood ends are often cut at other than a plain vanilla ninety-degree angle. A woodworking angle gauge makes life easier here (see pic). Also making things easier is the Mitre Sander. In the case of the forward top stringers, the gauge was placed on the two formers and the angle noted. Being that the stringers are 1/4” X 1/8” stock, it was very easy to just cut the stringer beyond the needed length and sand in the 100 degree angle on the Mitre Sander. If the stock were larger, I would have cut the angle on the Mitre Saw first and then sanded it smooth on the Mitre Sander.

The rear top fuselage stringers are next up.

Thanks for following along!

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 19, 2009, 07:03 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Went over the firewall former and main cabin former joints with a fillet made of West System epoxy resin and #404 filler. This combination cures to a very light and hard substance.

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 19, 2009, 07:08 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
The build was interrupted today by the call of a very important meeting at a remote and very secretive location. I am not at liberty to disclose more at this time...

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 19, 2009, 11:02 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Wanted to get to the top fuse;age stringers today, but was limit in time due to The Meeting...

Attached to the top of the aft cabin former is a smaller former that serves a couple of purposes. One is to hold the ends of the fuselage top stringers. The other purpose is to provide a place for the trailing edge of the wing to rest and blend the trailing edge to the top of the fuselage. This former is supplied by Sig in 1/8" balsa. I wasn't too keen on the idea of using soft wood in this area, being that the wing will be mounted and removed every flying session. I made a replacement former from 1/8" basswood. Harder than balsa, yet easy to sand.

EJWash
EJWash1 is offline Find More Posts by EJWash1
Last edited by EJWash1; Jul 19, 2009 at 11:14 PM.
Reply With Quote
Old Jul 20, 2009, 09:15 PM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
The top fuselage stringers presented themselves as a bit of a problem for me. I selected 1/4” X 1/8” hard balsa sticks to serve. The first problem is that the hard sticks did not want to bend easily to the shape of the fuselage formers, and I wasn’t comfortable with bending them and relying on a scant 1/8” contact are of the glue joint to hold them down to the formers. Steam to the rescue! I made a jig that would arch the stringers to shape they would be in on the formers. I then used a teapot to steam the stringers just beyond the arch and put them in the jig to set. This arch provided more pressure on the stringer against the fuselage former than the reverse, wanting it to spring upward above the former.

The next situation to address was the top of the fuselage formers. Being that the stringers meet the top of the fuselage formers at an angle because they are arched, and the fuselage former tops are square, there is a ‘V’ created and the stringer/former joint contact is minute. The top of the fuselage stringer was angled to match the stringer. Dry-fitting, clamping and glueing with Titebond followed.

I am not satisfied with the stringers simply sitting on top of the fuselage formers. I plan to extend the top of the fuselage formers by glueing a piece of balsa between the stringers. I will then sand down (scallop) the middle of this extension, leaving enough support to tie the stringer to the former.

This process slowed things down some, but will provide for a stronger attachment of the stringers and peace of mind...

Thanks for following along!

EJWash
EJWash1 is offline Find More Posts by EJWash1
Last edited by EJWash1; Jul 21, 2009 at 08:12 AM.
Reply With Quote
Old Jul 22, 2009, 12:14 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
First pics of extensions added to top of upper fuselage formers. After glue set, the added pieces were scalloped (cupped) as to reduce weight and so that they will not show on the covering.

The next situation that I ran into was that all but the first of the top fuselage formers has a cut-in shoulder for the top side stringers to rest on. Apparently one of the former’s shoulders was cut too deep, and this made a noticeable curve in the stringer. I missed it during the dry-clamping and didn’t notice it until I removed the clamps. I removed the stringer and added a piece of wood to the shoulder to bring the replacement stringer outboard. The replacement stringer is in place, nice and straight this time...

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 22, 2009, 12:30 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Weather observation:

A heck of a thunderstorm (tops in excess of 46,000 feet!) parked itself about 25 miles north of my neighborhood. Put on quite the lightning show, but not a drop fell on us. It did bring down the temperature to almost sweater weather...

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 22, 2009, 07:39 AM
Hamburger Eatin' Fool
TomCrump's Avatar
Traverse City, Michigan
Joined Dec 2005
11,141 Posts
Sweater weather ??? What, around 90 ???
TomCrump is offline Find More Posts by TomCrump
Reply With Quote
Old Jul 22, 2009, 08:05 AM
Closed Account
Joined Dec 2006
4,258 Posts
You need sweater weather, I'll be sending all you need from Northern MN. I don't think we've broke into the 90s this year.

With the bottom of the wing level, I'm seeing 00.0 on your digital meter. What is the wing incedence going to be?
Mode One is offline Find More Posts by Mode One
Reply With Quote
Old Jul 22, 2009, 10:48 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Quote:
Originally Posted by TomCrump
Sweater weather ??? What, around 90 ???
Exactly!

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Old Jul 22, 2009, 11:22 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
5,221 Posts
Quote:
Originally Posted by Mode One
With the bottom of the wing level, I'm seeing 00.0 on your digital meter. What is the wing incedence going to be?
The top of the cabin is parallel with the thrust line, that's why I placed the bubble level there. I just went back and mounted the meter bar to the top of the fuselage side (also parallel with the thrust line). "Acquired" (zeroed) the meter there and placed it on the horizontal stab rails, which are not glued in place yet. Meter read 00.1. Well within my acceptable sloppy tolerances...

I went over the manual and there is no reference to wing incidence there or on the plan sheets. Knowing Sig, if it was needed at all, it's incorporated into the build even if it is not mentioned. At any rate, I dropped them an e-mail to make sure.

Thanks Mode One!

EJWash
EJWash1 is offline Find More Posts by EJWash1
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion SIG 1/5 scale Cub MJFinegan Glow to Electric Conversions 14 Jun 08, 2007 09:20 AM
For Sale Sig 1/6 scale Citabria kit. Gerald Aircraft - Fuel - Airplanes (FS/W) 1 May 28, 2006 04:34 PM
Sig 1/5 scale Piper Cub Michael in Toronto Scale Kit/Scratch Built 5 Oct 04, 2002 11:30 AM