I AM COPYING AN LT40 KIT THAT BELONGS TO A FRIEND. MY QUESTION, IS ALL THAT PLYWOOD UP FRONT (LITE PLY) NECESSARY. IM CONCERNED ABOUT WEIGHT. THE OTHER KITS IVE SEEN USE 1/8" BALSA WITH A CUTOUT LITE PLY DOUBLER. WHATS YOUR OPINION.

IT SEEMS THAT YOU SHOULD BE FAMILIAR WITH BUILDING BIGGER THAN ABSOLUTELY NECESSARY. THE LT-40 IS MEANT TO TAKE A LOT OF ABUSE (IT'S A TRAINER), SO LOTS OF THINGS ARE "OVER_ENGINEERED".

On the other hand, the plane has been designed to be able to carry the extra weight. The extra weight is worth the benefits o being able to beat the plane around a bit (hard landings, etc).

SO, SINCE YOU SEEM TO UNDERSTAND FULL_CAPS LOCK, YOU SHOUDL BE ALSO ABLE TO APPRECIATE THAT AT TIMES, "BIGGER IS BETTER".

gus

I'd guess that the lite ply is to make it strong as a tank for student pilots. If you don't need that kind of strength, I say use lighter material and save the weight. Of course it could come out tail heavy and you have to bolt on lead to replace the weight of the wood.

tucker, the wing is big and if you build the plane as designed, the wing loading is as light as some gliders so you certainly don't need to worry about reducing weight. That being said why reduce the toughness of the plane??

I had a throttle servo slip loose and send the engine into full throttle on an inverted dive. Thus sending the Kadet into the ground at around 100 mph with a os max 46 ax! the plane was destroyed from the second former forward, but the rest survived, the doubled ply absorbed the energy and transferred it di- lineally. Thus preventing the total explosion of balsa. I rebuilt the nose in about 3 days. Back in the air this weekend.

I always like to think of it this way: Engineers designed the plane that way for a reason. Thousands have flown sucessfully. So why re-engineer it?

Go with the proven design.

Sounds good to me. Thanks alot guys. Oh, and Gus, I didn't use Caps Lock. OK! Dave

tucker1865

What Minnflyer said is an accurate summary after all argument is exhausted.

Appreciate that scratch building one from plans in accord with the original is a heck of a lot of work even with the availability of a scroll saw. Unless your budget is simply that restrictive or you just want the challenge, go with the kit. Even though it'll cost you more than the proliferate alternative ARF offerings, SIG's Kadet LT-40 is arguably the best trainer design in the marketplace today.

SIGRUN...I have all the woodworking equipment to do any job., scroll saw, band saw, table saw, planer, jointer, surface sander, drill press, routers, (template router bits in many sizes), spindle sander, 6 X 48 belt/disc sander, dremels, even a lathe. Admittedly some of this is overkill. Also I live near Superior Balsa and can hand pick my stock. Im retired and I like the building. Also a drafting table and drafting equipment. Thanks for your input. I will build the kit as designed. Thanks again. Dave

Hi Dave

If you have all that available to you, it'll certainly make the assembly of parts viable not to mention sigificantly easier. Because SIG use laser cutting with their LT, there's a lot of it and the fuselage is virtually all lite-ply. The LT derives not only form, but its strength intra-framework. If you enjoy building, you're gonna' love putting this design together as much as you will flying it.