bryris

Its taking shape. Since, I am out of school, I am putting it lots of time on this. I am going to try to have it done before I go back to school in Jan.

Its exciting watching it come together. Its my first plane and my first kit. Looking forward to its maiden.

Just figured I'd share it with you all.

cwrr5

My Feedback: (32)

Looking great so far!

I'm sure you have already thought of most of these, but here's a couple of suggestions: (having built a few myself)
1. Remove the motor until after you've covered it(and fuel proofed the firewall), so that you don't get balsa dust & yucky stuff into the motor
2. Use tri-stock epoxied on the backside of the firewall in the corners to reinforce it
3. Also use tri-stock under the horizontal stab when you get to that step, to give it more surface area to attach to
4. Before you cover it, sand, sand, and sand some more. Use progressively finer grit, say 150, 240, 400 or so. It makes the covering look much better.
5. Build a small hatch into the bottom of the fuel tank compt. for the battery, that's where mine usually end up after trimming and balancing. If you do this during the build, it makes it a lot easier later on

Good luck, post more pix as the build continues!

DVI

Looking Good
I built the LT-40 approx 3 maybe 4 years ago. I still have the airplane and use it when I have a guest that wants to give RC a try.
I power it with a 10 year old FP-40 engine and although it's no fire breather it flys great. The hardest part is landing the airplane because it just keeps floating down the runway.
Good luck with your project, They are a keeper!

fledermaus

Everything the other guys said about the LT-40 is right on! I built one last winter, and learned to fly on it over the summer. It is a wonderful trainer and I'm glad you chose to build instead of ARFing. You'll really get a thrill when you see your own work take flight.

A couple of other possible tweaks that my flight instructor and fellow club members suggested (all of which I did on my LT-40):

1) Replace the stock pushrods for elevator and rudder with Sullivan Gold'n'Rods. They don't expand/contract as much as the plain nyrods you get with the kit - and they are a tad lighter too since you don't have to thread so much 2-56 rod into them.

2) Support the pushrod tubes at every fuselage former station - this stiffens them considerably and reduces the amount of slop in your control response. It isn't hard to do even after you have built the fuselage. I just used the former drawings on the plan to mark and cut strips of 1/8 balsa to about 1/2 wide and about 4 long - so that they would run diagonally across the openings in the formers. I drilled them at the predicted locations of the pushrods (got it pretty close, too) and then when I ran the pushrod tubes into place I threaded the balsa strips on. Once the tubes were in the right locations, I adjusted the fit of the balsa strips against the front faces of the formers, and CA'd them in place on the formers. After that, I just ran some thick CA around the tubes at each support point to hold them firm.

3) Support the pushrod tubes inside the radio compartment about 2 inches behind the servos as well, using two strips of 1/4 square balsa across the width of the compartment. Notch each strip to take half the diameter of the tube. Glue the lower strip in place after the pushrods are in place and attached to the servos (so you know exactly where they will be). Glue the upper one on top, sandwiching the tubes. The supports don't need to be braced against the fuselage sides since they don't bear any significant stresses, but they do need to be firmly glued.

4) Use some tri-stock under the servo tray to increase the amount of gluing area. You don't want that tray coming loose in flight, and the extra weight is insignificant.

5) One other thing I did, that worked out ok but not perfectly: The stock attachment for the fin is a potential weak point. Some people like to put tri-stock along both sides of the joint between fin and stab. I tried something different - when I built the fin I extended the main vertical spar downwards so that it would be long enough to penetrate through the 1/4 thick stab and the 1/8 ply support deck beneath. I then carefully measured and cut a rectangular hole through the stab and the ply just large enough to snugly fit this extended spar. When the tail feathers are assembled, this means that the fin is supported at its leading edge where it notches into the turtle deck (if you can call it that on a cabin design) and also at its aft edge. THE KEY HERE IS ACCURACY, because you do not want your fin out of line. I got mine aligned nicely perpendicular to the spanwise axis, but I didn't quite get it vertically true because I got in too much of a hurry during final assembly. No big problem, the plane doesn't mind if the fin is a little bit off vertical as long as it is straight fore-and-aft. But I don't worry about the fin shearing away from the stab if I bump it getting the plane out of my van!

I powered mine with a Leo 46 (a knock-off of an older OS 46 design), and initially flew it with a 10x7 Master Airscrew prop. It always felt a little sluggish on climb-out with that prop, however, so towards the end of the summer I switched to an 11x6 MA. This required increasing ground clearance a bit, so I put 3.5 inch main wheels on, and used one of the 3-inch stock mains for the nosewheel. I extended the nose strut as long as it would reach without risk. The plane really feels much more solid in the air with the bigger prop - it isn't fast but it pulls strongly and smoothly in climbs where before it sort of waddled. I'm told that Master Airscrew props are not the most efficient and that I should try an APC, but we are ankle deep in snow now so that will have to wait for next year.

This winter I'm going to build floats for it!

[link=http://www.rcuniverse.com/gallery/galleryCat.cfm?memberID=74155]Click here to see My LT-40![/link]

cwrr5

My Feedback: (32)

fledermaus, have you thought about putting skis on yours? That's assuming you want to be out in that weather, I wouldn't myself!

Those are all good tips above! I don't usually use the nyrod tubing for rudder&elevator, as it's a straight shot back to the horn. I just use short 2-56 on 1/4" dowels, but thats just me. .(no reason for or against, I just like to keep it simple 'cause I hate that part.) I've never had a problem with control rods shrinking or expanding, but we don't have extreme temps or humidity(usually) where I'm at either

bryris

Your tips are great. I appreciate them.

Some of the advice won't really make sense until I get to the various stages of the build. This is my first kit. So far, I feel pretty good about it. Most of the mistakes that I have made (very few) could be categorized into the "ANAL" column. In other words, they don't affect the flyability, but would make me feel fuzzier had I not done that.

But, its gonna be great. I think I am going to build this one and learn on it, but start my second kit meanwhile. Haven't decided what its gonna be, but its just too much fun. And the next build will be even more precise.

Thanks again.

fledermaus

Re: Putting Skis on planes

Actually, some guys in my club have done that, but personally I don't see the attraction. Up where we are sunset is now at about 4:30 pm, and the daytime high is usually about -12 C with winds in the 20 knot range. Out on our field on the edge of town it would be pretty miserable just now.[:'(]

Bryris: keep building, don't worry about all the details. I am a beginner at flying RC but I have been building planes, boats, furniture, musical instruments, just about anything for years and one thing I know is that if you keep your head screwed on straight and think before you cut or glue, you probably will end up with what you want. It all makes sense (it has to or the darn things wouldn't fly after all) so you can probably figure it out - and if you can't, that's what RCU is for.

rfdias

Bryris, You'll like the LT-40...I built one (and still fly it) several years ago. And yes, it will float down the runway on landing. I would reccommend that you up the engine size (if you don't already have an engine). I originally flew mine with a ThunderTiger 42. It was ok, but really had issues in the wind. I flying in Sanfrancisco area at the time. Downwind, no problem, but into a headwind, it just crawled. Also, I to add a lot of weight to the nose to get it to balance. I recently went to an OS60 engine, and shimmed the wing abit. I got to take all the extra weight out, and now it flys with tremendous authority. flying into a headwind is no longer a factor.
Just a thought...Bob

If I can remember how to post a pic, I'll do so. Cheers, BD.

bryris

I have a .46AX for it. Only engine I own, I bought it for use in this airplane. It'll likely stay in there as long as this model is flyable (which I hope will be a while). When I buy my next plane, which will probably be an Edge 540 .60 size (still debating), I'll get a new engine for that.

I have been working a while on it. I had been post poning the glassing of the wing because of my limited experience with epoxy. However, I finally did it and am very happy with the results. I used 4" wide fiberglass tape and 45 minute epoxy. it has since hardened and looks quite nice. Just a bit of sanding to do, but not too much at all.

I also had to cut a custom servo tray for the wing. I am building it with dedicated aileron servos instead of just the one. So, I used a scrap piece of the fueslage wood and cut out side by side holes in it and the wing sheeting. It fits like a champ. So I am happy with the results.

I'll post another pic relatively soon.

xDennis

My Feedback: (2)

Wow!!

Plane looks really nice, I'm getting time to choose a kit for my dad as well and looking at your makes me want the LT-40. Do you know if the LT-40 is capable of aerobatics with the .46AX??


Thanks,
Dennis

GrnBrt

My Feedback: (5)

I have one with the 46FX in it and yes it will do aerobatics if you set it up right, great airplane and always have one in my hanger for those days when I want some lazy flying but also want to hot dog a bit.

fledermaus

Since I am a beginning flyer, I am not the best person to comment on aerobatics. Even so, after I got confident with the basics I tried a few maneuvers with my LT-40. I found it very hard to learn the moves simply because the plane really wants to fly straight and level if possible. There is a lot of coupling between yaw and roll, which makes rolls trickier than they need to be, as far as I can see.

Still, since more experienced flyers have said they can do aerobatics with an LT-40 I defer to them on this - but maybe it isn't the best plane to learn aerobatics on, simply because it is one of the best planes to learn to fly straight and level with.

bryris

It'll do some lazy aerobatics, rolls, and loops and so on. If you lessen the dihedral (I built mine with half the dihedral it called for), it is a bit more aerobatic.

bryris

Figured I'd post the latest picture. I am a proud father. (Pathetic, I know).

Looks the same, except that I have glassed the center of the wing, removed the motor to prevent balsa dust from getting in. There are a few cosmetic things that I have done as well, but they don't kow up in the picture.

Unfortunately, the construction has to halt for a week or so, I have to go on a 6 day cruise for Christmas (I know, I know....I'll be counting the days down until I can get back to work ) But, when I return, its the home stretch. Gonna build the tail, cover it up, drop in all the electronics, balance it, and then I'll take it out to the field and let the guys help me learn to fly it.

GrnBrt

My Feedback: (5)

The LT-40 has 3 separate balance points, beginner, intermediate and advanced. If the plane is balanced at the beginners spot then yes any aerobatics will be a bit on the sluggish side. Mine is balanced for advanced (almost tail heavy) and though it won't perform like a IMAC or pattern plane it can be a lot of fun. As you learn the plane and get some confidence start moving the CG back and enjoy!