Part FT Scout XL Wing Spar 1.0

[flitetest]

flitetest submitted a new resource:

FT Scout XL Wing Spar - Printable Wing Spar for the FT Scout XL

Printable Wing Spar for the FT Scout XL. Print with 10% infill and default slicer settings.

Read more about this resource...

 

[DaveM]

The addition of a 3D printed spar to the Scout XL is brilliant. From the video Josh shot for the U.S.S. Lexington episode, it appears the wing is simply cut in half and pressed into the wing slots with the spar inserted into one side (I would glue one side to avoid it sliping and ensuring the dihedral angle stays in the middle of the wing.

Does anyone know if the foam spar needs to be altered for the wing to accept the 3D printed spar? If no change is required, existing Scout XL's could be updated with the 3D spar (assuming the wing isn't too stoutly glued to the fuselage).

 

[Laszlo]

How about instructions for how to install it, what those holes are for (rumor is BBQ skewers), how the unglued wing is kept from falling off (rumor is rubber bands to the skewers in the mystery holes)? My SBK arrived almost 2 weeks ago, I've printed out the spar and I'm itching to go.

 

[alan0043]

How about instructions for how to install it, what those holes are for (rumor is BBQ skewers), how the unglued wing is kept from falling off (rumor is rubber bands to the skewers in the mystery holes)? My SBK arrived almost 2 weeks ago, I've printed out the spar and I'm itching to go.

2X

 

[alan0043]

How about instructions for how to install it, what those holes are for (rumor is BBQ skewers), how the unglued wing is kept from falling off (rumor is rubber bands to the skewers in the mystery holes)? My SBK arrived almost 2 weeks ago, I've printed out the spar and I'm itching to go.

Hi Laszlo,

I hope this info can help you. I was at Edgewater Airpark yesterday picking up my Scout XL and also doing some flying and I was able to talk to Josh about the Scout XL. He told me that the spar glues in one side of the wing. He also said to use bbq skewers thru the fuselage and rubber bands to hold the wing in place. I don't think the fuselage has the spots marked for the bbq skewers. The picture of the Scout XL in the FT store shows the rubber bands. You are probably going to have to guess where the spots for the bbq skewers go. Good luck with your build. I also plan to build the Scout with the removable wing.

 

[Laszlo]

Thanks Alan.

So here's a capture from the Lexington Flight video. You can see the foamboard strip that keeps the wing from going in too far. Above the wheel and below the trailing edge of the wing are the BBQ skewers that the rubber bands attach to. What this doesn't show is what's going on with the holes in the bottom of the wing joiner. Eddie at Flitetest support said "Basically you glue into one wing half with hot glue. The holes are for BBQ skewers that will allow you to rubber band the two wing halves together. That is all that will need needed to prevent the halves from separating in flight." I don't see anything about those spar holes. I wonder if they've been deprecated and it wasn't worth the trouble to update the STL file.

 

[alan0043]

Hi Laszlo,

Thank you so much for posting the picture of the Scout. I just don't have those kind of computer skills. It makes a lot of sense to have a stop on the bottom of the wing. To me it looks like a popsicle stick. Good luck with your build. I won't be able to start my Scout till after Christmas. I plan to make patterns of the Scout so if I need repair parts I have plans to help with any repair.

Al

 

[alan0043]

Hey Laszlo,

I was watching the last build video on the XL Scout. Josh shows the connection of the servo's and the receiver. I didn't think of this. I should have asked him when building the removeable wing of the Scout where do these connections need to go to for the ailerons ? I can understand using a Y connector for the ailerons. Probably come out of the top of the wing with the Y connector. I am still a rookie when it comes to this hobby and building a plane. I could be putting to much thought into this.

Thank for any input,
Al

 

[Laszlo]

I just watched the videos again and the space in the spar that acts as a wire channel for the fixed wing is filled with the wing joiner so that won't work. I'd just poke a hole in the back of the spar and route the wire through that into the fuselage. If you're feeling nervous, you could glue a foamboard doubler where you're going to poke the hole.

Note that if you don't use a Y-connector, then you'd be able to add flaperons to the plane, but you'll have to change the config file and wiring.

 

[MackDan]

flitetest submitted a new resource:

FT Scout XL Wing Spar - Printable Wing Spar for the FT Scout XL



Read more about this resource...

Admin,
Can you give me the dimensions of the spar?
The dihedral angle:
box dimensions : HxD
Half width along top edge (so the joint to tip dimensions).

My brother is trying to 3d print, but its too big for his M2 Makergear bed. I'll redraw it in Fusion 360, split into 2 or 3 parts with an overlap joint and send you back the files. OK?
I uploaded the .stl file to fusion 360 and got some weird dimensions, 338 mm (13.3") for the depth of the box and 195mm for the height??

Thanks Dan

 

[Laszlo]

I'm not an admin so I can't give you the data you're looking for, but Flite Test already has in the form of the plans.

You can get the dihedral angle from the plans using the dihedral gauge on page SHEET-3 and the 1/2 wingspan from page SHEET-1. The wing assembly video shows you which points to measure from. The 1/2 wingspan will be the hypotenuse, the dihedral gauge height the side opposite the angle you're looking for. Sine is opposite over hypotenuse, so just divide the gauge height by the 1/2 wingspan and take the arcsin of the result. As long as you use the same units for the opposite and the hypotenuse it doesn't matter whether you use imperial or metric or pixels off your screen. As long as you use the same scale when taking the measurements it doesn't matter which page of the plans you use. Just be sure to have your calculator set to degrees, not radians.

The box has to fit snugly into the A-fold in the main spars, so you can get the box cross-section dimensions from SHEET-1 in the plans. There are inch and cm scales up in the top right corner of the page. You can use those and a drafting scale to get the actual dimension of the inside of the main spar A-fold.

Once you have those dimensions from the plans, you should be able to compare them to what Fusion 360 tells you and make any necessary scaling adjustments to the length.

Finally, keep in mind that those overlap joints are going to need to be strong. The plane's all-up weight is 3 lbs. If you do a 4-g pull-up from an inside loop, that weight goes to 12 lbs. The standard safety factor for beams is 2.5, so that wing spar should be able to support 30 lbs to routinely survive serious aerobatics. And remember it has to work the other direction, too, if you're flying inverted or doing outside loops.

Rather than jointed PLA, it might be better to make a one-piece hollow wooden spar with an internal brace, all glued with high quality wood glue.

Good luck.

 

[MackDan]

I'm not an admin so I can't give you the data you're looking for, but Flite Test already has in the form of the plans.

You can get the dihedral angle from the plans using the dihedral gauge on page SHEET-3 and the 1/2 wingspan from page SHEET-1. The wing assembly video shows you which points to measure from. The 1/2 wingspan will be the hypotenuse, the dihedral gauge height the side opposite the angle you're looking for. Sine is opposite over hypotenuse, so just divide the gauge height by the 1/2 wingspan and take the arcsin of the result. As long as you use the same units for the opposite and the hypotenuse it doesn't matter whether you use imperial or metric or pixels off your screen. As long as you use the same scale when taking the measurements it doesn't matter which page of the plans you use. Just be sure to have your calculator set to degrees, not radians.

The box has to fit snugly into the A-fold in the main spars, so you can get the box cross-section dimensions from SHEET-1 in the plans. There are inch and cm scales up in the top right corner of the page. You can use those and a drafting scale to get the actual dimension of the inside of the main spar A-fold.

Once you have those dimensions from the plans, you should be able to compare them to what Fusion 360 tells you and make any necessary scaling adjustments to the length.

Finally, keep in mind that those overlap joints are going to need to be strong. The plane's all-up weight is 3 lbs. If you do a 4-g pull-up from an inside loop, that weight goes to 12 lbs. The standard safety factor for beams is 2.5, so that wing spar should be able to support 30 lbs to routinely survive serious aerobatics. And remember it has to work the other direction, too, if you're flying inverted or doing outside loops.

Rather than jointed PLA, it might be better to make a one-piece hollow wooden spar with an internal brace, all glued with high quality wood glue.

Good luck.

Laszlo, Yeah, I'm thinking about different joint designs to help with the strength.

 

[MackDan]

FT Admin, and all,
Here is a glue-able 2 piece version of the Scout XL main wing spar, that will fit on a 200mmx200mm 3d Printer bed. There is a left and right version, since the hole location is not symmetrical (21mm up from the bottom edge, 18mm down from top edge). I left 0.5mm glue gaps on the long faces and 1mm glue gaps on the small end faces. Those are the net gap for 2 parts. I would suggest using a epoxy meant for plastic.



FYI, I ended up just printing a copy of the original, but divided it at the dihedral bend with a dovetail joint. And then printed it vertically with minimal walls and infill so it only was about $0.50 to print. Yes, its the low strength direction, but I'm not going to use it in a plane, its just a throwaway. Then measured and redesigned in Fusion 360.

 

[alan0043]

Hi Guys,

I have a question for you guys about the size of the spar. I have an Ender 3V2. Looks like the bed size is 220x220x250 mm. I have downed loaded the files for the spar from FT. I tried to put the files into the slicer but it looks like the spar is to large for a Ender 3V2 bed. Am I correct on this ? I was hoping that the spar would fit on a di-angle from corner to corner. The corner to corner size looks to be about 275mm. The original print seems to be to long. Do I need to down load down load Mack Dan's two piece spar ? If so, no problem here. I am working on the Scout XL. Hey guys please point me in the right direction.

Thanks guys for any help,
Al

 

[Laszlo]

I printed the Flite test file on a Prusa i3 MK3s that has a 210x210x250 build volume. Maybe the problem is the slicer?

 

[alan0043]

I printed the Flite test file on a Prusa i3 MK3s that has a 210x210x250 build volume. Maybe the problem is the slicer?

Hi Laszlo,

I'm curious to know the length of the spar you printed ? How did the spar fit into the wing ? I am using the Creality Slicer. I am a rookie when it comes to 3d printing. There could be something that I am missing when it comes to the files that I have down loaded.

A little side note. I am only use to down loading files from Thingiverse. The FT files shows a picture of the part on a grid. I am not use to seeing the part to be printed that way. How do I change things up to get the files to look like the files from Thingiverse ?

 

[Laszlo]

The bed on my printer is 210mmx250mm and the max vertical height is 210 mm. So that's why I was able to print it. It pretty much just fit on the bed. So if your bed is 220mmx220mm and 250mm high, it won't work. The joiner is about 3 mm too big for a 220x220 bed when laid out diagonally.

My joiner fits snugly into the spar from the speed build kit.

I don't know what you mean by a picture on a grid. I don't see any difference between FT files and Thingiverse files when I display them. I think all that depends on the program you use to view the STL files.

 

[alan0043]

Hi Laszlo,

Thank you for getting back to me. It doesn't sound like a Scout XL can be printed on a Ender 3V2 bed, that's ok. When it comes to the picture on a grid, it seems to be only a 3D object. This was the info that I get from the down load from FT. It says 3D object. I have no STL files that show up from FT. I have looked at Thingiverse have not found any files for the Scout XL spar. On to plan B. Sounds like I need to print the 2 piece spar.

Thank you again for your help,

 

[Laszlo]

The download button on the resource page mentioned at the top of this thread (located under the social media buttons) downloads an STL file named 447249_cbce96d31a00409d8e34fb651c314c47.stl when you click on it. I've attached a picture with the download button marked.

As far as the size issue goes, if you have an STL file editor, just cut 5mm off each end. It'll still be plenty long to function. FreeCAD will let you edit STL files.

 

[alan0043]

FT Admin, and all,
Here is a glue-able 2 piece version of the Scout XL main wing spar, that will fit on a 200mmx200mm 3d Printer bed. There is a left and right version, since the hole location is not symmetrical (21mm up from the bottom edge, 18mm down from top edge). I left 0.5mm glue gaps on the long faces and 1mm glue gaps on the small end faces. Those are the net gap for 2 parts. I would suggest using a epoxy meant for plastic.



FYI, I ended up just printing a copy of the original, but divided it at the dihedral bend with a dovetail joint. And then printed it vertically with minimal walls and infill so it only was about $0.50 to print. Yes, its the low strength direction, but I'm not going to use it in a plane, its just a throwaway. Then measured and redesigned in Fusion 360.

Hi MackDan,

Thank you for the files. I was able to print out the spar. The spar halves match up nicely. Thank you again. Al