Sequoia 2m - Build log

[thenated0g]

I picked up a Sequoia 2m from @Wayne and will be documenting the build process here.

From the store listing:

Sequoia 2 Meter

This is the sort of plane we dream about at Aloft. We love finding well thought out and well made gliders. We stumbled across these and had to bring them in. When they arrived it was like Xmas. I have been flying slope gliders for many decades and you know a well refined design when you see it...

alofthobbies.com

AIRFOIL	HN 785 7%
WINGSPAN	2 Meter
EMPTY WEIGHT	about 850g, 30 ounces
RTF WEIGHT	from 1130g, 40 ounces
CONTROLS	Aileron, Elevator, Flaps, Rudder
CONSTRUCTION	Foam / Wood Wing, Carbon Reinforced, Fiberglass Fuselage
FUSELAGE LENGTH	1150mm

I have read thru a ton of similar builds on rcgroups, but this will be my first "kit" build. I plan to keep it stock with the exception of adding a ballast tube in the fuselage under the wing joiner tube. Probably a carbon tube as i have those on hand.

From the product description it appears that the wood is finished already.

Here are the electronics going in:
6x Corona DS843MG servos
Double Wall Pushrods for tail controls
Frsky RX8R Pro RX
6v 1300mah nimh battery
and ill try and stuff in a vifly finder 2 lost model alarm.

 

[thenated0g]

This morning i cut out some test cuts to make sure my circle diameter matched the wing holes and that my servo cutout i designed from the online dimensions were not too tight.


And than i took those and combined them into something that would work in the wing:


They are made out of 3mm birch plywood, 2 layers glued together. Im leaning towards some shoogoo or similar glue to hold the wood in place but need to test on the foam first. Feels like some kind of epp, so it may work. If not ill go epoxy/filler. Its a pretty tight fit so i think just some glue on top will be enough to keep the servos in place in the wood and make removal easier later.

 

[Konrad]

Shoo Goo in my experience will eat polystyrene. I'd clean the pocket to expose the top wing skin. lay down some carbon cloth as a load spreader using epoxy to cover the exposed top wing skin in the pocket. (But your servo mount might have much the same load spreading effect). I'd then mix up a very dry epoxy and micro balloon mixture and glue down the servo mount. (You look to have a lot of surface area, so bond strength shouldn't be too much of a concern).

I'd add a lot of fillet material around those stab receptacles.

Love the idea of a 7% airfoil!

 

[thenated0g]

Thanks @Konrad, aside from sharing the experience, the other main reason to post here is for helpful info.

**edit - What would you suggest as far as covering the hole over once the servos are in place? I do have some of the aloft servo covers, the white thin plastic.

 

[Konrad]

Those are fine. I like the glass Blejzyk covers. But with your fab skills I'm sure your own design would fit best. Do you need a servo bump with that thin wing?

 

[Hank GB Z]

@thenated0g

Signing on to watch the build. I like your servo mounts you cut out.
Hank

 

[thenated0g]

Thanks @Hank GB Z . There are a ton of other ways to cut these and they have been done that way a hundred times before but having said that, having a laser is pretty great. The no noise and mess while cutting with a laser allows me to work in my shop before my daughter wakes up for school. And repeatable cuts and small changes are just a couple keystrokes and than 30 seconds later i have my new set of mounts.

I plan on doing the same for the fuselage tray that will hold all the electronics. I just need to get the ballast tube in first so i know what space i have left.

 

[thenated0g]

Oh and once i get set on a design ill share the svg/dxf files in case somebody wants them for cnc or full size print on paper for cutting out by hand.

 

[Wayne]

Nate - Silly idea for the cover and servo mount. Since you have nice plywood mounts, you could make another plywood circle that fills the hole. Have a slit in the round to let the servo arm come through. Then small wood screws to attach it to the lower servo mount plywood. This would also lock the servo down in the wing. Hope that makes sense. This assumes you don't need a bumped cover. Use simple Z-bends on the servo linkage and you are done. Maybe a little plywood skid next to the linkage to protect it from the ground landings..?

 

[thenated0g]

That make sense and is easy to do. I will just have to sand the trailing edge to match the wing surface.

 

[Wayne]

But keep this stuff light. That is the amazing thing about this plane, she is a feather.

 

[thenated0g]

@Wayne heres a version to try tomorrow. Blue areas are fill, basically engrave, remove material to try and flush mount the screw heads.

 

[Craigp]

Great log so far!

 

[thenated0g]

v2

 

[Konrad]

Love how easy it looks to come up with a revision.

Do you need so wide a slot to clear the servo arm and linkage? Are you forgoing the hood? Also does the cover lie flat with the bottom of the wing surface? Or are you going to sand the cover to match the bottom contour?

 

[thenated0g]

Slot is just a guess while drawing and after comparing to the parts it is way too big.
I like the simplicity of this instead of a hood, but will probably put something in front of the horn so it doesnt get ripped off on landing as @Wayne suggested.
The cover does not lie flat as is. I will probably adjust a little with epoxy/filler underneath but probably will have to put down some masking tape and sand it flush. I had also considered using something thinner like 1/32 for the lid but again would require me to get the layers up higher to match.

Ill probably just sand down what i have to match the surface.

 

[Konrad]

The hood is far more than a linkage guard. For your reading enjoyment, look under Aerodynamics (in the side bar) and flap linkage. It is shocking that the linkage drag from a 4 servo wing is close to the drag from the tail.

MainFrame

 

[thenated0g]

@Wayne since the finish is wbpu, what do you suggest as far as adding some orientation stripes or marks? My first thought was some vinyl that i have.

Also, what is the preffered glue/method for sticking the thin plastic servo covers to the wings?

 

[Wayne]

You can use paint, tinted WBPU, vinyl etc. All work really well. The EPS foam inside the wings is very prone to melting with chemical contact, so keep those nasty melty style spray paints away as they tend to find pin holes in the finish and melt the foam. It is hard to argue with the good looks and simple install of Vinyl.

Plastic servo covers? I usually use scotch tape to stick them down. I used to be fancy and use a rubbery glue, but it was a pain to do any service. Tape is great.

 

[thenated0g]

V1 of a servo tray. Still adjustments to be made but all the electronics are fitting nicely.