3d-aholic

My Feedback: (7)

I would like to build my SPAD3D as a 40-sized. That means I need to cut some weight out of the design. Can anyone unequivocally confirm by way of trial with some other spad that you cannot use the L-shaped aluminum rod. I've repeatedly gone to the hardware store to compare it with the U-shapped and its significantly lighter and it really doesn't appear to be that much less strong. I would beef up the area around the wing and but 2-L's together to form a square rectangle with a few L-brackets to maintain the wing shape. That really only leaves the tail as an L.....

FrankC29

Which L, the 3/4" or the 1"? I would imagine the 3/4" being a bit flimsy for this task, but you never know. The 1" will probably work just fine. You might want to consider running the music wire through the flutes in a place were it will also pass through the fuse, this will help revent the wing from turning on the fuse. I don believe there is much weight difference if any between 1" L and 3/4" C though, and c-channel is just easier to use for a Spa3d.

3d-aholic

My Feedback: (7)

and c-channel is just easier to use for a Spa3d.
___
Yes...I also have a problem with the idea of prying the C open, getting my servos only half-way down and having the pressure of the C on the sides of my servos. I have cracked servo sides open before by mistake....its really not that hard to do. That was the other reason for my idea. My Futuba servos look bigger than the Hitecs or something...

I put pressure on both at the hardware store and I could not bend them very much...where I could bend the L...I found the C to be nearly as easy to bend on that axis. The square tube is in its own class though and not comparable with either.

It sounds like its an unknown though...no one has specifically tried it.

Any other way to cut weight down to manage a 40?

Tattoo

This is the forunner to the BUHOR and the fuselage was 1 1/2" aluminum "L" channel. The plane flew awesome, however the fuselage was EXTREAMLY flexiable and the twist between the wing and tail was quite unerving with every turn.

3d-aholic

My Feedback: (7)

Ok thanks... [:'(]

Well, I'm going to go check the dimensions on servos, because those HiTec ones have to be smaller.

rlt55

Some of the older HiTec servos fit in real easy, but some of the new ones
I've used are fatter. Instead of 0.75, they are around 0.80" wide.

It's very easy to make them fit. Just tape off the sides, leaving 1/2" of
the bottom exposed and use sandpaper to take off some of the plastic.
I used a small sander and it only took about 15 seconds a side.
They came out a little smaller on the very bottom and that made
them even easier to install.
On the HiTec servos, just sand down to the edge of the screw-heads
and you are there.
The amount of plastic you remove is about 15 or 20% of the wall thickness.
You will not weaken the servo at all.

3d-aholic

My Feedback: (7)

Oh, no...I don't want to sand my servos....[X(] I don't have any old servos for this....

I just checked. I have some Tower servos and they advertise .77 wide. But the U-material is .75 OD not ID. ID is less than .7

southern_touch9

My Feedback: (3)

Dont worry about using a different metal to cut weight. Just cut your Uchannel 32" and your wing span 32" and go for it. I have builty them this size and they hover under 1/3 throttle.

3d-aholic

My Feedback: (7)

Yes, thats kinda where I'm at now. I was thinking 34" on the wings though...lol. I'm getting rid of all of the metal through the wings and using the lighter wire gear. I've purchased my coroplast so I'm ready to start soon.

3d-aholic

My Feedback: (7)

Tattoo:

Duraplane gets away with the tiny 1/2 U-channel for the tail section...don't they? Thats what it looks like in the manual and the pictures when I was looking at it before. Is that stuff stronger than the L...? It didn't seem like that at the hardward store.

rlt55

Well, I have to admit, the servos that I sanded don't look as glossy on the bottoms,
but if I wanted stuff to look neat, I would take up art instead of SPAD flying

For channel, go to ACE hardware and get:

Steel WorkS
ALUM-TRIM CHAN
For 3/4" Plywood -8 FT.
SKU#58907

It's inside measurement is 0.758 inches.
A HiTec HS-300BB is 0.80 inches.
You will have to sand off 0.042 inches.
Or 0.021 inches off each side..
(I'm not sure, but I think the servo case walls are a little over 0.1" thick).

But, you really don't have to sand off that much,
you could get by with less (0.018?), but it's going
to be harder to push them into the rail.

FrankC29

Actually the Duraplanes use 3/4" U, the same exact channel for the Spa3d. You can pry the channel apart a bit if you are worried about the servos, are you can install the servos sidesaddle, there is a tutorial on how to do this on the Spad site usiing a poly "H".

southern_touch9

My Feedback: (3)

The smaller 32" wingspan doesnt really seem to affect stability all that much. There is a slight difference but if you had never flown a 36" then you wont know the difference.