tmaxx1701

Thanks Rich,

I have a Saito FA 182TD for it. Maybe a little more than I need but I am also building floats for it so more power can't hurt.

tmaxx1701

Not a lot of progress in the last few weeks. Took a break with the holidays.

I have finished the hinge point install for the rudder/fin. I have the holes drilled for the elevator/stabilizer but need to finish "insetting" the points.

FlyerInOKC

My Feedback: (6)

Tail feathers sure came ut nice. I love your choice of power plant.

tmaxx1701

Thanks,

I still have to round the edges but wanted to do the hinging first as it is easier.

ThunderBoat42

My Feedback: (1)

Power has arrived for the Sig 1/4 Cub. It’s so nice I am just going to stare at it a while 🤣
waiting in the Ceconite from Aircraft Spruce next.

FlyerInOKC

My Feedback: (6)

I hope the bank teller realizes you didn't blow all that bank robbery money frivolously!

tmaxx1701

Starting the wing assembly with the center section. I plan on making this at least a 2 piece if not a 3 piece wing assembly. After looking at a number of Sig 1/4 scale build threads I noticed that the clipped wing and full wing kits have a unique center section. The clipped wing is set up to be a one piece wing so it uses a ply rear dihedral brace instead of a rectangular "tongue" in the center section for alignment of the wing sections. I will use a 3/8" hardwood dowel in the rear of the center section for alignment and then some 1/4x20 plastic wing bolts to secure the wing sections to the center section. I have added a ply doubler to each of the ribs at the joint between the center section and right and left wings. This should be stiff enough to hold the wing together.




Still have to drill the holes for the attachment bolts and alignment dowel

tmaxx1701

Center section is now complete except for cutting access holes in the bottom surface for the wing bolts.

Gluing the front dihedral brace

Finished top view

Finished bottom view. I will be cutting 4 access holes for the wing bolts and the wing servo wires.

FlyerInOKC

My Feedback: (6)

Looks great!

tmaxx1701

A bit of an update.
The right wing is almost finished. I have to add the laminations on the wing tip and fill in the shear webbing that I removed to install the strut mount t-nuts. The left wing is in process. I learned on the right wing and I am installing the t-nuts before the shear webbing is finished. I still have to build the pocket or box for the dihedral brace, finish the sheeting and add the wing tip.

Right wing with servo mount. Need to fill in the sheer webs where the strut mount t-nuts were added.

Left wing in progress

Strut mount going in before the sheer web this time.

FlyerInOKC

My Feedback: (6)

Back at it I see, nice work!

tmaxx1701

Thanks, just poking away at it each night as I can. Progress is a little slower due to trying to plan out the build steps and I have altered the structure of the wing to build it in 3 pieces.

Dave

tmaxx1701

Quick update.

The wings are together, sanded and filled. Need to mount the center section to the fuselage and then cut out the ailerons.

scottrc

Sorry for a late reply, but this cub got me thinking of my past.
It looks a lot like an old late 80s Aristocraft cub. They made a 55" and a 80". I had the 55" with foam core wings and after stripping the shelf paper off, this is what it looked like . I think they made an ARC versions, but I cannot find anything on it.

tmaxx1701

It has been a while since I have added an update. The ailerons are cut out of the wing and hinged. I designed and 3D printed a drill guide for the Robart pin hinges. I also added and shaped the cabin blocks. Next is mounting the elevator and rudder servos and running the control rods.


Aileron cut out of wing and leading edge glued to wing

Backer blocks for the pin hinges

Blocks added to wing

3D printed drill guide. It was too wide so I trimmed it on my scroll saw.

hinges installed in wing

Ailerons hinged

Cabin blocks shaped and installed.

FlyerInOKC

My Feedback: (6)

Nice work!

tmaxx1701

Here is some more progress on my Cub. I'm at the stage that progress is slow with what seems like twice as much time. Trying to plan out and execute the servo installation and control rods. I went with Sullivan 4-40 gold-n-rods. I added blocks where the rods will exit the fuselage. Added supports to reduce the flexing of the rods and built a removable servo tray for the elevator and rudder servos. Added a mount for the throttle servo on the right side of the fuse and then added the throttle cable. Finished off with building a tray to hole the RX and RX battery just in front of the servo tray. Hopefully I can get this finished in the next month or I may just have to put off finishing till next winter.

Gold-n-rods installed

Exit at the rear of the fuselage

Supports in the middle of the control rods

Supports towards the servos

Servo tray

I used t-nuts in the tray supports and the attachment of the servos to the tray

Throttle servo mount glued to the side of the fuselage

Throttle cable supports

Battery/RX tray and switch mounted

paulinfrance

You aren't worried about the weight ?, captive nuts and 3mm bolts for the servos and sullivan bike cables for the commands, I have been using the screws in the servo bag to hold them down and 1.5mm piano wire for the commands, although I do use cable push / pull on some of my planes, weight is the enemy of planes.

acdii

a couple extra grams won't hurt a Cub. Just slap a larger motor on, it will fly. You should see mine with an FA-100 on it, takes off and goes pure vertical like an F-15, yet at 1/4 throttle putts by like a real one.

tmaxx1701

Hello Paulinfrance,

This is a 1/4 scale Cub that I will be installing a Saito FA 182TD glow engine. I don't think a few grams of extra weight will affect the flight performance The expected flying weight of this plane is 6500 grams. I figure I will have to add some ballast in the tail to offset the engine as it is.

I have had experience with the servo screws threaded into balsa coming loose or having the hole stripped out. The addition of the captured nuts on connections that may be removed and installed many times makes it worth it to me.

Cheers,
Dave

paulinfrance

ohh that's a big one, I hope you put locktite in the servo screws,,

tmaxx1701

Yes I will when i do the final install. I will be pulling the servos in and out of the tray a number of times before it is ready to fly.

WacoNut

A guy in my club is finishing up a 85% Cub with. 20hp 4cyl boxer engine. I will get with him and see if he minds if I post some pics.

SU29

My Feedback: (20)

Dave,

I'm jealous, I lost my Sig 1/4 cub this past summer and I'm hoping to get another one some day. As far as the elev and rudder servo mounting, there's several ways to do it and I know your all done, which looks like a real secure way to do it. FWIW, I used 1/8" plywood for the servo tray (not sure what size you have there) and because the ply would flex a little I glued 1/4 x 3/8 hardwood to the bottom of the plate at both ends of the servo. This greatly stiffens the plywood plate. I then drill holes for the servos through the plywood plate and into the hardwood below. I soaked with CA and have never had any screws come loose. I seem to have issues with the blind nuts turning in the wood when I try to remove them, especially when using Loctite.

Anyway, great job, hope you get it done for this season....

Jeff

paulinfrance

That's what I do,screws in good quality wood.

So Waconut, is his 85% cub an ultralight plane or just a silly size rc model ?.