Note - Posts on pages 1-5 contain the primary build. Pages 6 and on discuss the maiden and some improvements.

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Got the last of my stuff today from UPS so I got to work!



Got the left wing partially built tonight...



These pieces fit together really well - seems like a really quality kit so far as I can tell with this being my first build/plane. Can't wait to lift this off of the ceiling tile in the AM!

I learned that toothpicks and q-tips are really useful when working with wood glue. Going to do this build using Titebond II primarily.

Also installed the blind nuts for the engine mount and CA'd those.

Total build time: 5 hours

somegeek

Most of the stuff I bought for this setup...

Sig Kadet LT-40 Trainer Kit .30-.40,70"
O.S. .46 AX ABL w/Muffler
Futaba 6EXAS 6-Channel FM/4 S3004 Servos

Convert to tail dragger:
Main - Great Planes Dural Landing Gear Large .60
Tail - Sullivan Tailwheel Bracket 40-60 5-12 lbs.
Tail gear shaft collars
Tail gear wheel
Tower Hobbies Plywood 1/4x6x12" (1)

Dubro S12 Square Fuel Tank 12 oz
Great Planes Spinner 2-1/2" Aluminum
APC 11x5 prop
O.S. A3 Glow Plug Hot
Dubro Foam Rubber 1/4"
Dubro Foam Rubber 1/2"
Dubro Socket Head Servo Mounting Screws (24)
Great Planes Steel Clevis 2-56 (12)
Great Planes Pro CA Glue 1 oz. Thin
Great Planes Pro CA Debonder 1 oz
Northeast Hobby Products Epoxy 30 Minute 8 oz.
Ultracote, Corsair Blue - 1 roll
Ultracote, Cub Yellow - 3 rolls
Hobbico Fiberglass Cloth 3/4 oz. 1 Square Yard
Carbon fiber pushrods - 1/8" x 36"
Dubro 2-56 Steel Fitting for 1/8" PR
NHP 341 Black Flash Ca for Carbon
2-56 Dubro 12" threaded rods
#67 Sig Rubber Bands
Midwest Aerogloss 3.5 oz. Swift White

X-Acto Razor Saw Set
Great Planes Slot Machine Cutting Guide
Top Flite Sealing Iron
Top Flite MonoKote Hot Sock Iron Cover
Cool Power 15% Fuel 4 Gallon
Dubro Kwik-Fill Fuel Can Fitting
Dave Brown Six Shooter Fuel Pump Glow
Dubro Kwik-Start XL w/Charger
Tower Hobbies 12 Volt AC Charger
Hobbico Quick Field DC Charger MKII 12 Volt
Hobbico TorqMaster LC 12V 7Amp Battery
Great Planes Aluminum Fuel Line Plugs (2)
W.S. Deans 2-Pin Ultra Plug
Hobbico Tx/Rx Charge Leads No 9VAP Futaba J
Hobbico Panel Ready TorqMaster 90
Hobbico 4-Way Wrench w/Plug Storage

Bottle of Titebond II wood glue.

Various grits of general woodworking sandpaper.

Ceiling Tile on a large piece of 3/4" MDF - to keep a flat working surface.

Clothes pins (had 40 - wish I had 100).

Wax paper for working surface when gluing.

CA was rarely used - primarily for the hinges and small repairs where it's wicking quality was great.

Epoxy should be used for the MADB mounting, securing the wing joint, glassing the wing joint, firewall mounting, horizontal stabilzer mount & fin mount.

Titebond II was used everywhere else.

Looks good so far. This plane needs to have tringular stock added under the stabalizer for sufficient glue area and also from the stabalizer to the fin for the same reason. I normally add DuBro main gear (replacing the wire) and a Fults Double fork nose gear. The nose gear is important as the single forks have a tendency to bend in one direction. I have built several as club trainers and it is one of the very best available.

EXCAP232

Thanks for the info...

I ordered the triangular stock when I ordered the plane. Also have the hardware to convert this to a tail dragger.

somegeek

Finished the right wing last night and got the left wing built tonight and started on the fuselage...



Second wing half assembly went a bit quicker since I knew how it went together a little better.

The wax paper is great with the wood glue... it pulled away from the first wing half that I built just fine - nothing stuck!

I wanted to pin down the first fuselage doubler but no dice since I ran outta T-pins. Gonna need a lot more to do the fuselage doublers. Shoulda picked up another 40 pack or maybe two more.

One problem I did run into was that the shearing pieces on this half of the wing seemed a bit too narrow so as I built a few of the ribs were not lining up exactly perpendicular to the trailing edge. I ended up adding a few 1/8" pieces to a set of the shears (dark pieces in image above) to get the ribs back into proper alignment. Everything else was pinned in place and square when I started adding the ribs. Only thing I can ponder is that the shearing pieces were a tad bit too narrow. So I have about three ribs that are from 1/16 to 1/8" of an inch off between the leading and trailing edge. Will that be a problem?

Total build time: 15 hours

somegeek

The build is looking great, keep up the good work. If I may make a comment. One thing that happens sometimes when building an airplane comes when you start the fuselage. It's possible build 2 of the same sides of a fuselage, 2 right sides or 2 left sides. Here's a couple of tips that help prevent it. Pull out all of the parts needed to assemble the fuselage and use a marker to label them with a "R" and "L" on the inside of the parts. Then when you build the fuselage lay our BOTH sides at the same time, and lay them out mirrored from each other. I'm making the comment because I see only one side of the fuselage in your picture. And trust me, it's a lot easier to make this mistake than it sounds. Some of the best modelers out there have made this mistake (and yes, I have too).

Hope this helps

Ken

The shear webs do not need to fill the area between the ribs. Next time concentrate on rib placement. What you have will work fine.

A big Ditto to both Ken and Bruce's last comments.

RCKen - thanks for the advice - will do!

bruce88123 - wish the instructions mentioned something regarding that - DOH! Given a space is too wide for a shearing piece, would it be fine to attach to only three sides? I'll know better on the next plane I build. Thanks!

somegeek

3 sides is fine. The important thing is to attach to the spars. Attaching to EITHER rib is a bonus. The web is there to reinforce the spars and turn the structure into a type of I-beam. Well OK, a C-beam in this case. The extra web greatly stiffens/strengthens the assembly and reduces flex.

I know you are using TiteBond and I heartily approve of that, great glue.
When I glue the doublers I will apply the wood glue as needed and then put just a drop of CA at each end to maintain alignment. Once the CA sets, put wax paper above/below the piece and weight it down evenly until dry. NO PINS! Put the CA in a place where you won't be sanding later.

Looking great so far... I commend your choice of glue, it's better in the long run! (Elmers is cheaper BTW)
Don't worry too much about the shear webs, they do add strength and rigidity to the wing, but aren't absolutely required.
I'm not a fan of cutting up the plans myself, but they're your plans.

I really like how several people are setting out all the materials for a picture before the build actually starts (ie:somegeek-LT-40, Mountaineerfan-4*60). It really shows an accomplishment when the kit is built, and is great documentation for those that are just starting out. It makes a nice side-by-side comparison to show before and after type thing....
LOL! Maybe someone can say all of that a little better??? My brain is stuck at the moment.

I've always cut my plans up, and then an older builder at our field kind of jumped me for doing that. So now what I do is I will take the plans down to Office Depot and have a copy made. I then cut up the copy and I keep the original intact, I roll it up and store it in a tube with the instructions for future reference or repairs.

Ken

Exactly! Best of both worlds!

Plus, if you keep the original intact and build from a copy, you don't end up with a plan that looks like moldy swiss cheese from all the glue and pin holes, and you can reuse it if you build another plane.

Do'n a great job so far. I find it hard to build and stop and document.

Just to add a log on the fire, ref post #2 from excap. I've been teaching on LT 40's for 10 years now. I've seen them built by experts and 9 year olds. Even had one show up at the field with the entire fuselage held together by the covering, because he didn't read the step where you're supposed to glue the whole thing together.

But, in my opinion.

You do not need to add aditional stock to hold the horizontal stab on. I've never seen one break off under any conditions when built as stock.

The triangular stock at the base of the vertical fin help if you can't make a good joint. Kinda wise design on SIGs part in that if you flip over on the back the fin ususally snaps off rather than doing more damage to the airplane. But this one is a 50-50.

The gear that comes with the kit is nice and soft. Frankly it's mushy and it bends. But the flip side is that you can easily bend it back to the original shape. And it absorbs the energy of those first hard landings. If you keep your Kadet, then upgrade the gear as post #2 suggests. You may have to beef up the MLG contact area to carry the loads of the less flexible gear. (Yes, I've seen modded gear tear the bottom out of the Kadet.)

Another possible weak area in the kit is the elevator push rod may be too long. In some planes it flexes. This is critical in recovering from a dive. I've seen two planes lost due to lack of up elevator. The cable flexed instead of pushed. Suggest you "trap" the rudder and elevator tubes between two popsicle sticks glued to the frame halfway between the servos and the tail. Just a little insurance before you cover it all up.

A great time saver is once the wing is lined up where you want it to be, add four 1/4 x 1/4 x 1 or 2 inch blocks on the lower wing skin where it touches the inside of the fuselage. These insure positive alighnment every time you drop the wing on. Saves some retrimming everytime you fly. Of course the harder solution to the same problem is a dowl pin in the front of the wing and a hold down screw(s) in the back as found on the ARF Kadet. To add the blocks, install the finished wing on the fuselage and get the alighnment correct. Draw a fine line on the lower surface of the wing at the OUTSIDE of the fuselage. Remove the wing and draw a parallel line to the first one where the inside of the fuselage would be. Remove just enough covering to allow the wood blocks to have good contact to the wing skins. If not done already, iron down the covering around these new holes. now glue the 1/4 square blocks down and either monocoat them or seal with glue. Voila, positive allignment.

RCKen - next plane - I'll do that. Thanks. :-)

MajorTomski - thanks for the info!

Regarding the elevator pushrods, I picked up some 1/8" carbon fiber rods and will build guides out of the 1/8" ply that the fuselage punched out of so minimal flex should occur on that control.

Great tip on the wing alignment blocks - will definitely do that!

Thanks,
somegeek

bruce88123 - took your suggestion and weighed down the doubler vs pinning it. Used 130 lbs of dumbells on top of some MDF board pieces and it worked great.



Glue squeaked out of about 95% of the edges so the glue coverage was good. Hit the areas where no glue seeped out with CA.

Sig pre-drills the dowel holes (vs their instructions stating you need to drill them) so alignment of fuselage and the doubler was a cinch. Covered the doubler side with glue and stacked it on the fuselage side, inserted the two dowels through both layers, stacked the wax paper, MDF and weights accordingly, spun the dowels every 5 min or so for the first twenty minutes so they would not set and then pulled them out. Left the weight on for about 4 hours a piece. Worked well!

When I glued the second side, I layed down the first side I glued together next to it to reference to make sure I was gluing the other side properly. [8D]

Total build time: 17 hours

somegeek

Exactly what I had in mind.

130 Lbs. Should do it!

Build Looks GREAT

Thanks all for the words of encouragement.

This was a very cool step... sanded the left wing panel W1 face so all was flat and then glued in the main dihedral braces. A set of small C-clamps, some scraps of wood and wax paper did a great job of clamping those pieces to the spars for a good bond. While that set, I sanded down the other W1 face and then cleaned up the wing tips. Was really neat to see the wing tips form as I sanded down the spars and edges. Time to join the wing came and after some preliminary fitting and sanding it looked like I was only going to get about 75% of the specified dihedral unless I did quite a bit of carving(will explain below). Figured that would just make the plane a little less forgiving so I will deal with it. Made sure the wing was lined up by standing it on it's leading edge on the counter and made sure the middle was all lined up and got to tacking in place with the CA and then clamped it up for the final gluing. Was cool to take all the clamps off and hold the finished product in my hand!



After that I moved onto the fuselage assembly. Used every rubber band in the pack I bought - the more the better I figured. Glued F1-3 & the fuel tank floor tonight. Added some weight to assure the sides bonded well with these three pieces.



This is something that confused me... the pre-cut dihedral guage had a curve to it on the side that contacted rib W1. The lower edge was less angled so the rear of rib W1(shorter) was less angled which contributed to the lesser overall angle of the dihedral that the joining surfaces created. Am I missing something here or should this guage be flat on that side?



I'm enjoying using the wood glue vs the CA. Used the CA on the wing joint and the partial fuselage assembly - stuff sucks with regard to the fumes bothering my eyes and the stank. Yuck...

Regarding the wing balancing... will this be done after I cover the wing? One side is slightly heavier than the other. A small plastic clothes pin on the end of the lighter side causes the wing to balance evenly on the dihedral.

somegeek

Total build time: 24 hours

You didn't ca the two wing halves together did you? I may have mis-read but it sounds like you did. Should have been 30 min epoxy. CA on a wing joint just wont work. IMO

You should probably static balance the wing uncovered as close as even as possible,by sanding away[X(] the heavy end. After adding Monokote, Control Surfaces and associated hardware, rebalance it, your adjustments should be minimal at best. Then of course you do a lateral balance on the plane fully assembled, RTF minus fuel. Again doing the balancing as you go insures a minimal correction as you go.
Is that pretty close to right Major T?

Somegeek,
I too came away from reading your post thinking that you joined the wing halves with CA. If this is the case you need to stop and fix this. The wing halves need to be joined with 30 minute epoxy. If not the wing halves will most likely separate during flight. This is a very high stress joint and you need the strength of epoxy to hold it together.

Hope this helps

Ken

I have to agree with the majority on epoxying the wings together. Why did you use CA? This will not be easy to fix either. [:@]

WHOA!! hold on all.

A glue joint is a glue joint. Period. The only thing epoxy offers over ca is buttering capability. The strength of the joint, if it was a good mechanical joint in the first place will not change with the type of glue. I've got Kadets older than most of you that the firewalls were installed with CA and have held up fine, training people mind you, for years because it was a good joint to begin with.

In the case of somegoofs wing, let's understand what the parts are doing. The dihedral joint wing joiner is just that, it holds the dihedral angle and carries the loads from one wing side to the other. As I recall that piece of wood sits in a pretty tight pocket formed by the upper and lower spars, front and rear shear webbing and the first set of ribs. Once the two panels of the wing are joined that brace is not going anywhere. It is in a tightly sealed pocket. Now ANY glue flowed down into that hole before or after the joiner is in place is going to stop any minor movement between the upper and lower spars and the joiner. All three, CA, wood glue and epoxy have about the same capacity to do that work in this area. The mechanical fit of the joiner in the pocket is doing the work the glue is just minimizing the ability of the wood to loosen up the joint. The wing panels are held together by the friction in the wing joint pocket AND all of the glue on the flat surfaces of the innermost ribs. And if you goof that up, there's a pair of suspenders covering everything in the form of the fiberglass tape you put over the joint.

If you did use just CA don't worryaboudit. Add the FG tape and press on.

Um, oh yeah, me... aero engineer, former Chief Structural engineer on the USAF C/KC-135 fleet. Glue up 1:1 wood airplanes too.

Tom

I'll chime in here on Tom's side... IF the joint is solid. If it wasn't a struggle to attach the wing halves by sliding the dihedral brace in, then it's not tight enough. The fiberglass tape will help, and in fact - that's what it's there for, extra strength.

The wing halves won't have very high forces pulling them outward, most of the load is trying to either bend the wing up or down(compression on one or both main spars). I fly several planes that aren't glued in the center, so as to make it possible to disassemble for transport+storage, only difference bieng they use bolts and dowels to attach to the fuselage instead of rubber bands.

I'd say somegeek is probably ok in this case, but I would very carefully check the joint to make sure it's seated correctly before adding the fiberglass tape and pressing on.

Hey aero engineer, only thing in a KC-135 that I remember being wood is the floor... besides what some of the pilot's used for brains...