Has anybody cut one or more ribs off the an LT40? Pros?Cons?

Why am Iasking? Just wanting input before Irecover my LT40's wing.

Thanks for you valued comments.

Lots of people have clipped the wings on the LT-40. If you search for "LT40 clipped wing" (no dash) or "LT-40 clipped wing" you will find lots of postings about it. The general opinion is that since the LT-40 has a VERY light wing loading and tends to float as a result, you can shorten the wing without much problem.

The clipped wing will mean it lands a bit faster of course, and will be less suitable as a basic trainer...

I tried doing exactly that before I started this thread. Results were pretty much limited to the clipped wing Cub - not bad but not what I was looking for. Em ... Iused the old search with "LT40"and "clipped wing". I'll give it another shot ...

Just tried the "new"search and result were better ...

Yeah - the search on RCU isn't the best and you have to try a few variations to find everything.

The LT-40 is a downsized variant of an older SIG kit called the "Kadet" - in fact the full name of the LT is "Kadet LT-40". There is a website dedicated to kit-bashes and mods of the Kadet and the LT-40 at [link=http://www.angelfire.com/indie/aerostuff/kadets.htm]http://www.angelfire.com/indie/aerostuff/kadets.htm[/link] that shows clearly just how forgiving this airframe is to modification.

I've had 2 Seniors - ARF (solo plane) and bashed kit (pontoons, tail dragger, cowl). We have a 4 engine and 2 engine variant at the field. Very popular with "the kids" regardless of age or skill. We estimate that 50% of our club membership has a Kadet (300 members in the club).

Clip it! Why not?

While its still uncovered flatten it too

note:not a LT40 but is my "trainer"

<span style="font-family: Comic Sans MS">what do you mean flatten it? the airfoil? sanding down the ribs? </span>

Can't wait for the reply.

I'm assuming remove the dihedral.....

did it to mine.. lots of fun

I think that it would be more prudent to leave the dihedral asis with this wing and cut a new set of ribs for a wing with zero tolerance (or 1 degree) of dihedral.

One thing I've noticed about the LT - elevator and rudder authority is just fine. However, roll performance sucks (to put it bluntly). If I clip the wing I'll probably add some more surface area to the aileron.

For some reason flattening the wing takes something away from the LT-40. I had a guy step on mine and [:@]

i believe the official RC term for that move is "WING WALKING" ,capt

I have found that rolls in an LT-40 are a tricky proposition. Part of the problem is the amount of dihedral which fights the commanded roll, part of it is that the full-span ailerons are not particularly effective because they have such narrow chord (remember, this is designed as a basic trainer not an aerobat), and part of it is that with a 46-size engine the plane is not moving particularly fast. You get into the knife-edge part of the roll and the plane just doesn't want to go any farther around, but you now have zero lift.

After a few almost-disasters, I gave up on rolls and stick to loops and stall turns. Even with floats on my LT-40 will loop if you dive first to get up some airspeed!

Hmmm... Both of mine with TT 46 Pro and an 11 X 6 prop barrelled rolled just fine. Now an axial roll was out of the question. At least for me.
John

OK John - I'd love to know how to do a scale-like barrel roll. Will you PLEASE explain to me the control inputs to do one? I've asked many at my field - "dun-noh - good question" is the typical answer.

I'll refine my comment - my LT's axial roll "suck".

With the LT 40 any roll you make is a barrel roll. Nothing to do with talent - shove the aileron stick all the way over. It's not on the axis, it seems to roll about a 1/2 wing span out.
John

Well, JNorton, I just have to hand you a great big compliment if you can get your LT to roll just by cranking the aileron over. I have tried several times to get that to work and it's a damn lucky thing I still have my LT-40 - and a damn lucky thing I didn't hit anyone on the ground too!

I find when I have tried to barrel roll, if I enter the roll in level flight I get halfway around, the nose drops (i.e. in a right-hand roll the nose falls off to the right which is ground-wards) and down she goes. If on the other hand I enter the roll in a slight climb (as in a "victory roll") the airspeed isn't as high and the full right aileron leads to a lot of right yaw - the plane just veers over and I have never held it in that attitude long enought to find out whether it will roll or just crash.

I also have tried using opposite rudder to counter the yaw during the roll, and maybe keep the nose up as it passes through knife edge, but that was a near-disaster too.

Maybe I'm just a bit ham-fisted but I figure the type certificate for the LT says "no rolls or deliberate spins allowed"... at least as far as I am concerned.

It sounds to me like you do not have enough airpeed. What motor are you running with what prop? Both of mine would easily do a full size loop with no fall out at the top from level. When I was training my brother-in-law and son on the LT40 I was using about 1/3 to1/2 throttle.
John

Loops have never been an issue with mine - originally powered by an Evolution 52 - full throttle resulted in nearly a 45 degree up line without any up elevator. As a tail dragger it needed nearly 16 oz. of nose weight (lead, multiple Rx batteries and a heavy hub) to balance. I'm converting it back to a tri-cycle gear and hopefully eliminate the wasted weight - then an OS 46 FX.

So, back to the thread topic (duh) I think that the weight loss and clipped wings will neutralize themselves.

I have a knock-off of the old OS 46 SF, the Leo 46, turning an 11x6 APC prop. I get about 11000 rpm at full throttle and the plane flies nicely for most purposes. It loops well although generally I need to dive a bit for extra speed or the loops are a bit floppy.

Maybe I don't have enough aileron throw to get smooth rolls - I have not made any set-up changes to the plane since I used it to learn RC flying 6 years ago. In fact, I have been flying it on floats for the last 4 years, and I haven't been attempting rolls so I kind of forget the details of how it handled back with the wheels on.

As Seamus said, back to the topic - there is plenty of lift in the LT-40 wing so you can afford to clip some of it off if you want.

This "clipping" project has grown horns. [:@]

I recalled that I used the LT for "practice" building a "sheeted built up structure" for both the stab and fin. I was building a GP Extra 300S at the time that used this particular technique. I used Titebond - resulted in really warped pieces. So I used the repair of the LT to practice for the Extra. Nice-n-straight but heavy. They have both been removed and replaced with SIG-kit recommended approach. Nice-n-light - straight too. I noticed that as a result of a couple of hard landings there were cracks in the fuse side in the rear. Those got repaired (replacing lite ply) and the stab supporting section was replaced - eliminating a bunch of epoxy. The plane has had 3 engines mounted. The firewall looks like repaired Swiss cheese. Just cut it out and fabricated a new firewall. When I removed the covering (Ultracote) the heat gun softened the "epoxy micro balloon" putty to the point that it was worthless. It's been removed and I'm working on getting the wing saddle set for a +1.5 incidence relative to the stab.

I must really be bored ....