Chuck86

Been reading all these build threads and decided I couldn't let you have all the fun so...... I have an LT-40 sitting on the building board. I have several questions that I need everyone's advise on:

1. I would like to build this kit with dual aileron servos. How far out in the wing should they go? I would like to mount them sideways inside the wing with just the servo arm exposed through a slot. Need a lot of instruction/drawing on how to build the servo mount with recommended sizes of wood to use. Also, how much torque will these servos need for this plain......can I use some of the smaller size to cut down on weight?

2. Don't want to use the wire main landing gear and would perfer to use one of the one pc designs. What mods do I need to make to the bottom of the fusalage? Add some plywood? How big of pc and how thick?

3. Back on the wings.....I have seen some of you recommend adding holes in the ribs to allow air to move to aid during covering. This kit has shear webs on the main and secondary spars...so alot of trapped air. Is it worth adding these holes, and if so, what is the best way to make them??

4. Fuel proofing. Think most people use epoxy but will a good fuel proof paint work just as well?

Not sure if I should have put this in the beginners section or not......wanted you experienced guys to comment

sticktickler

1. The best way to put servos in the wing is to simply mount the servo sideways on the hatch door. Then you install hardwood rails in the center wing bay on each wing panel so you can screw said hatch door into the hardwood. I counter sink the holes in the hatch and use tapered flush screws for a clean look. A standard servo will work just fine as the servo case is flat on its side in the wing bay, any weight savings of smaller servos would be insignificant. I use this method on all of my planes. See images of my scratch built .60 size Ugly Stick and my 32cc gas Sig four Star both are done in this manner. Also notice the large fillet of glue on the servo mount block on the hatch. You don't have much glue area here so make the best of it build it up with thick CA and hit it with kicker as seen in the pics. Some wrap masking tape around the servo and epoxy the side of the servo to the door as well. The masking tape helps with servo removal if needed at a later time but provides some added servo holding strength for larger planes.

2. I love the arched composite landing gear from Dubro (see first pic below gear is on Ugly Stick). Simply use the same ply bottom the kit comes with but measure new blind nut hole locations to correspond with the Dubro gear. If you beef this area up to much you can seriously compromise the planes airframe on a hard landing. You want the ply gear plate to pop out in those situations which is easily glued back in with little effort.

3. As far as adding holes in all your ribs goes don’t worry about it air finds its way out. However you will need to put ½” holes is the ribs out to the servo bay section for the servo leads to pass through. I roll up some computer paper into tubes and glue them into the wing to allow the leads to pass easily through each rib when the wing is covered. You can also buy 1/2" paper model rocket tubes on e-bay for this job they work great. A hole must be cut in the wing top center for (ON BOTTOM MOUNTED WINGS see pics) the leads to emerge from the wing sheeting for receiver hookup. (ON A HIGH WING THE LEAD HOLE MUST BE ON THE WING BOTTOM see pic)

4. For fire wall fuel proofing I use Rust Oleum Enamel found at Walmart in many colors it is very fuel resistant but takes a good day to dry.

Chuck86

Drilling hole in ribs......stack them up, wrap some masking tape around them and use a regular drill bit? The balsa is so soft I don't want to tear it.

On the servo mounting, I have seen pictures of it done this way but the bay, or area between ribs, on this model seems wide, wondered if it needed to be divided with some framework and using the hatch on a smaller area.

Sorry guys. Newbie here.

sticktickler

DO NOT DRILL IT WILL NOT WORK! Simply take a small 3" piece of 1/2" coper pipe sharpen one end on the inside with a xacto blade. Rotate the tube holding the blade to the edge. Now use this coper pipe to drill the 1/2" hole in the stack of ribs it works much better than a drill and will not damage the ribs.
You can make the bay area smaller if you like it matters little in the end as long as the hatch is flush is the goal.

SeamusG

All I did was to pick the rib bay that was central to the aileron as the servo bay. This was an upgrade of a kit that was originally built with a single servo. I added two "half" ribs made from 3/32" balsa sheeting. Icreated servo mounts from a laminate of 1/8"ply (no lite ply here) and 1/4" balsa stock. The mounts are as long as needed to fit between the two ribs. Rectangular cutouts to locate the ends were cut from the rib "doublers". Some scrap balsa sticks were fit around the perimeter of the servo mount kinda like cap strips to support covering.

HTH

Oh yea - drill holes in the centers of each rib between the servo mount and the root rib for the aileron servo wire. Iused a 3/8" wood bit.

raydar

Enjoy the build its a great kit and a great first plane, I still have mine a year on and still fly it.

Btw if this is your first plane there is no reason to fit dual servo to this plane as one servo is plenty good for the job, with the big wing andsmall ailerons this planewill always have big slowrolls.Some of the more experience fliers are prob fitting two servos so they can experiment/play with different set ups but this could end up causing problems for a newb. Im not saying dont do it as this hobby is about having fun and experimenting but you will still have a great flying plane built standard.

Also I have pancaked my lt40 in a few times and although the wire landing gear is soft and requires bending back now and again it is a great shock absorber for poorlanding skills, dont make your new gear to strong or it could be the fuse that gets damaged and not the gear.



One thing I wish I had done when building this plane is provide fixing points for floats in the fuse for even more fun.

As I said great plane. Nice and strong for begginer abuse