I'm on call this weekend so I'm stuck in town and at home. An excellent opportunity to build my first airplane!

I purchased an LT-40 ARF for this task along with a HiTec Exlipse 7 radio and an OS .46LA Engine.

I'm going to update this thread as I go through the build process, it might make enjoyable reading for some people. My goal is to get the plane completed by Monday. This upcoming Thursday is the monthly meeting of the local flying club so I'm hoping to have the plane completed for show-and-tell.

First, some comments about the LT-40. In general, I'm pretty happy with it. It seems well built and the ARF requires still a fair amount of assembly without the fear of majorly screwing up.

I'm a little disappointed with two aspects of the instruction manual, however. First, it must be out of date, because several of the the steps required (cutting some of the covering to expose the balsa, mounting some parts, etc) are actually already completed. Slightly disorienting. Second, there is nearly ZERO explaination of how the wing assembly actually attaches to the fusalage. No specific pictures, no text, nothing. In addition, when you look really closely, the pictures show rubber bands and posts for them, but in reality it hooks under a lip and then screws into place with some nylon thumb screws. It's really infuriating that this important piece of directions is missing.

In any case, the assembly is going pretty good and I'm including a link to some pictures.

Again, I'll update this thread as I work through the installation.

EDIT:
Per requests, I'm going to post the pictures direct instead of linking to my web server.

Have fun with it!! Did you know that you can upload images to RCU and display them in your post (have to keep the images small as per RCU info)? You can also use the IMG tag to link the pictures directly from your site. Like this!! If you link, make sure the pics are not too large or they are hard to view.




Ross

Some More pictures:



And my friend Gandalf wanted to help out as well!

Another update:

First I put on the rear wheels as well as the steerable front wheel. That process was pretty simple:



Next was to install the engine. This gave me quite a few problems getting things lined up properly. After I drilled out the engine mount, it was badly off center, requiring me to use a popsicle-stick shunt to get it to line back up.



In the end though, it looks pretty good



Finally, I installed the 11x7 recommended propeller along with the plastic nosecone.



Next step is the radio gear, so I'm going to take a break and go over that chapter in the manual a couple more times before I charge into that.

Looking good. So is the cat gonna get an sticktime on this? When installing the radio watch the play with the steering servo on the front gear. I have an Alpha trainer, as you already know , and I am fighting the pay in that wheel. makes it hard for straight take offs.

No pictures in this update.

Installing the radio and mechanics has proven to be "not fun".

First, I went to change the arm on one of my servos for the steering/rudder and the screw stripped. Finally had to dremel away the stock servo arm so I could get a grip on it with some pliers. Now I gotta find another screw or use CA to attach the servo arm.

Next, Catzilla managed to mangle one of the nylon push rods that controls either the rudder or elevators when I wasn't looking, so now it won't slide in the rod tube any more. I'll have to go out tomorrow and get a replacement one

Finally, these "Z-bends" I'm supposed to make in the control rods are at best "unpleasant". I've had two snap off while bending into place. Plus, my diagonal cutters won't cut through the pushrod wire. I finally had to switch to a cutting head on the dremel and just brute my way through it. Thankfully, I only have a couple more to make for the rudders.

There seems to be some inconsistancy about how rods are being attached. In some places, they have you do the Z-bend thing, in others there is a clevis and in still others some other kind of a mounting aparatus. Why not just do them all the same? *shrug*.

SIG have released an updated amended instruction manual for the LT-40 ARF. It's listed on their website. Suggest you contact them for a copy. It's not downoadable TMK.

sigrun

SIG encouraging the acquisition of skills?

For rod connections to the servo, unless you have a z-bendng tool, I recommend you just do 90 deg bends and use snap-link connectors. ie: Dubro 855 "E/Z Links" They are inexpensive, secure, robust and simple. You can view them here.

http://dubro.com/du-bro/DUB_CAT/Dub_cat_Frameset.htm

Alternatively if you have a soldering iron, nothing beats the combination of maintenance free security, smooth movement and functionality of a soldered clevis. That said, unless driven by newbie enthusiasm, I wouldn't bother with them at the servo end on this occasion. Snap links will more than suffice at the servo end for rudder, elevator and aileron on the LT-40.

BTW, lose the 11x7 on the LA for the LT-40. An 11x 5" pitch preferably made of something other than wood will serve you best. Master Airscrew make a nice high aspect ratio standard blade that will work very well in that diameter/pitch combo on the LT-40 airframe.

When did they replace the rubberbands with bolts?

That seems really, really stupid.

I built my LT-40 ARF about 18 months ago, today (first day at a new field), she nosed into a field from about 30' up.

The rubberbands really saved the wing from damage.

Anyway, its a good flying airplane, but has a tendency to want to float a long time on landing.

Oh, and if you trim the "ARF" off the wing decals I won't tell. :-)

Ghostbear: I have a sneaking suspicion that "ARF" will magicly disappear from the wing decals. *whistles innocently*

sigrun: I picked up the 11x7 prop based on the instruction manual for the engine. I've havent yet fully groked what changing the size and pitch of the prop would do for performance.

As for the varried connection types, I do suspect it's Sig embracing a variety of techniques. For right now, I'll just do what the book says and see how that works.

I just put my LT-40 ARF together in May and it still had rubber bands. I haven't had a landing where they were needed...yet.

GP and others make Z-bend pliars. Still, the Dubro fasteners might be the way to go.

I've tried a few different props on my airplane that were all withing the recommended range (I am running an Magnum XLS 46). Part of the fun is seeing how the airplane performs with each one.

The LT-40 is a great trainer...very forgiving. You might outgrow it quckly, but is a great confidence builder.

I ditched most of the standard decals. You can do a lot to set even an ARF apart from the crowd.

Gandalf's Slave ,

I haven't dealt with an ARF myself, but here are some things to consider before you finish it:

Your pictures look like the engine and fuel tank area might be bare wood. If so, you should coat the bare wood with epoxy or some other fuel-proof coating. If it's not already done, it's good to strengthen the firewall-to-fuse, the landing gear block, and the wing hold-down blocks with fiberglass and epoxy. If they're competently assembled with epoxy already, you might be OK to leave it.

Give the control surfaces a little pull to see if the hinges have been sufficiently glued.

Check the air in the tires

Another minor mod is adding triangle stock to the base of the vertical stablizer (fin).

When I built mine there were a lot of people that recommended that due to a few seperating in flight.

I got my LT-40 father's day weekend and I have the nylon screws to hold on the wings not the rubber bands.

Minor update - no pictures yet:

Went to the hobby store and got a new pushrod as well as some clevises. Per some of the recommendations here, I also picked up a piece of 3/8" sheet basla to cut to size and mount on the underside of the tail to serve as a drag plate

The wing servo is mounted and hooked to the ailerons. Elevator is hooked up, as is the rudder/front wheel. The foam-wrapped battery is still rather loose, so I need to rethink and repack the radio gear a bit and then put the receiver in. At that point, the only remaining thing to do is the fuel tank and then the wing decals.

Sounds like you are making good progress now that the cat has lost his taste for plane parts I had my battery wrapped tight eonough that there was a little movement to reduce shock but not loose that it would slid out easy. After you balance your plane you could take a strip of velcro and secure it in place. make sure to put some foam around your fuel tank to cut down on the bubbles. make sure the throttle pushrod doesn't bind though.

I ended up putting fiber tape under the tail and under the wingtips to protect them on landings. My guess is like most people you will need that protection.

I didn't start out with the triangular stock on the tail, but ended up with it after a relatively minor run off the runway jarred it loose. You might consider that as well.

The instruction manual says the engine compartment is already treated, but it didn't look like it so I treated it with epoxy thinned with alchohol.

I think the nylon screws are an upgrade. It would have to be a pretty nasty accident for the rubber bands to do any good.

The plane is done! Well, except for the wing decals - I'm still deciding if I want to do something different up top instead of the stock decorations.

First, some basic pictures:




With all the trouble the radio gear gave me, looks pretty close to the manual (that cable strewn in the middle is the Airilon servo cable):



And here's a closeup of the port side. Note the gap between the body and the wing is simply because I didn't tighten the wing-screws down all the way. I ran the antenna down the side where it blends with the black striping.



Finally, I did my one piece of customization and installed a Great Planes Switch/Charge Jack mounting kit on the port side. This provides me with a push-pull on/off switch as well as an external RX recharging jack, so I don't have to go fumbling through the fusalage to find the cord.



Yes, I did mess up cutting out the hole (was about 1/2 inch too low) so I had to do a little touchup with some monocote tape. We won't talk about this ever again, will we....

Finally, here's a closeup of the engine with the muffler and fuel line attached:



Commentary will be in the next post.

wiEngineer,

You mentioned props. Here's a quick primer.

11X7:
11 = diameter (in inches) equals "torque" or pulling power, especially vertical pull.
7 = pitch (also in inches) equals speed. Theoretically, 7" pitch will pull the plane forward 7 inches for every revolution.

General rule of thumb: If you increase diameter by an inch, you decrease pitch by an inch (to prevent taxing the engine), and vice versa. (Reducing Dia. nd pitch will increase RPM, sometimes beyond peak efficiency. Similarly, increasing both will reduce RPM, sometimes with like effect.)

The OS 46LA is not known to be a powerhouse, so the 11X5 recommendation may be a good one, especially for break in. You want a prop in the lower end of the manufacturer's recommended range for break in anyway.

I have a well broken in 46LA and it handles an 11X7 pretty well.

Sounds like you're making good progress, and you've had some terrific advice. Keep us posted!
Dennis-

wiEngineer,

Nice job.

Funny story. Last weekend I was flying. I live in Colorado and the winds can kick up quickly. It was maybe a 5 knot crosswind when I took off and before I knew it it was 20 knots gusting to 30 right across the runway. I did some approaches but thought it would cartwheel when the wind picked up a wing so I decided to land in the grass just off the runway. The airplane came down like an elevator and I landed without a hitch.

Enjoy the airplane, it is a great trainer. I'm ready for the Sig 4* 60 I am finishing up, but still plan to fly the LT-40 too.

I entered into this project with a little bit of trepidation. I'm NOT very good with my hands, especially in tight places. In fact, I'm at least in the running for the King of the Klutzes award for 2003. 15 years ago, I made a brief foray into R/C by building an RC-10 electric car and it was a complete disaster due to my clumsy hands. Thus, when my brother got me keyed up to look at model airplanes again I was pleasantly surprised to see that now, 15 years later in the hobby, there is a nice proliferation of well-made ARFs which suits my building skills just great.

15 years ... man I feel old....

In any case...

SIG KADET LT-40 ARF:
First, the plane itself. All told, I figure I spent about 30 hours building the plane. I could probably easily knock 10 hours off of that if I had to do it again, especially if I was to forgo the external recharging jack (more on that below).

All in all, the Kadet is well put together. I noticed only one minor issue that I could see with the construction. The pre-installed aileron control rods have a pre-cut channel to move in, and those channels are not the same length. Thus, the left and right aileron don't have the same amount of possible travel. I don't think it will matter since the servo won't require the full throw, but it's an inconsistancy that jumped out at me. I suspect this minor flaw is unique to my unit.

I mentioned above the fact that the manual doesn't match up with the plane that's delivered. This wasn't a show stopper, but a person could easily get confused, especially regarding the attaching of the wing to the body which is completely absent from the book in ANY form. Poor job, Sig! I can only hope that the updated manual mentioned elsewhere in this thread reaches the sales channels before long.

---

O.S. .46LA ENGINE:
While the engine itself hasn't flown yet (or even been started for that matter) I did want to make one quick comment regarding it. The engine is a very cool (IMHO) cobalt-blue color. However, the muffler and carb is a traditional gunmetal-grey color. Why bother going through the hassle of designing and selling a blue engine only to make it clash so distinctly with a giant grey muffler? Seems rather silly.

----

HiTEC ECLIPSE 7 RADIO
This is one complicated radio and it will be a long while before I understand all the nuances of it. However, there was one thing I wanted to comment on here. The radio came with 4 422 digital servos. However, when removing the stock round control arms to put in the straight ones, the head on one of the screws stripped out and I eventually had to dremel the round nylon contol arm off to get a grip on the screw with a pair of pliers. Not really a complaint towards HiTec per se, really could happen to any servo. Hard part seems to be in finding a replacement screw - guy at the hobby shop said the only way to get one was to buy a new servo.

---

GREAT PLANES SWITCH & CHARGE JACK
I saw this in the Tower catalog for $3 and I figured "what the heck". It essentially provides an external plug for charging your receiver as well as a push/pull on-off switch all in one nice little housing.

I really wanted to install this on the top of the aircraft behind the wing so it would be easy to get to on the flight line. Unfortunately, it wouldn't work out that way due to the fact that the wires on the receiver's on-off switch (which mates into this assembly) were too short and I didn't want to try splicing and extension into it. So, instead I decided to mount it to the port side.

Ugh. What a PAIN IN THE *ahem*.

It probably took me 4 hours to get it installed. The problem was that the space I had to work in was very cramped and my butterfingers didn't help any. In addition, when I cut the hole out for the assembly to poke through, I was 1/2 an inch too low.

That said, I think in the end it looks pretty good, but I recommend against it unless you know where you want it and how you are going to get it there.

---

All in all, a good build. I'm looking forward to showing it off at the monthly RC club meeting (ho hum, another trainer; boring but I'm proud of it) and hopefully getting it into the air later this month.

You can paint the muffler to match the engine. I can't remember the exact colour but you get the paint at Auto zone. Do a search on these forums for auto zone or some such thing to find it and the post has the exact colour number. Plane looks very good.

Dear sir,
Congratulations on your purchase!
It is the and I do mean THE best arf on the market in the 40 size!
I know I have flown virtually all of them out there over the course of the last ten years. I own a lot of big gas planes and I still get my biggest thrills from making the LT 40 do what a trainer is not supposed to do like fly 3D!
I would be very happy to help you every step of the way. As a nugget it is only natural for you to find out that one answer will lead to many more questions. feel free to contact me via email @
[email protected] IM me if you have aol or the best and fastest way to get immediate satisfaction is pick up the phone!
Home:847-797-1742
Cell: 847-204-5193
I have just started to build my web site please pay me a visit at
www.tothextremerc.com
Double left click on a picture and it will bring up more of that plane.
Sorry it is so sparse at the moment been too busy flying a lot more to come over the winter.
Again please don't hesitate to contact me with all of your questions. I would love to help out.
Captain Ron Jarvis
Chicago

Hi well done! The LT-40 taught me to fly! I miss mine! aileron servo striped out and it rolled over on it's back and well you get the picture!.....

I suggest you turn your exhaust to the out and down position! this will help drain excess oil and fuel out of the muffler. Also use blue lock-tight on the nut. Or it will depart in flight! never to be seen again.