FT Mini Arrow

[xMeox]

yes it is 44mm in front of the firewall.

let us know how she flies with a 3s 2200 battery. As I sold my 1000 3s recently, I only have 460er and 2200. With fpv gear Ill use two smaller but without the 2200 would be awesome

 

[octodreamerFNG]

so how big of a deal is it to monkey with the dimensions until it will carry a 3300mah 3c?

i've got a bunch of useless parts from the old knuckles quad + laser toys power pack that i could never get to work... wondering if i can adjust the scale of the plans on this until it'll work.

here's the parts i have access to (obviously 4 each on the motors, props, and esc's)

3300mah 3c
motors - Emax grand turbo 2213/935kv
ESC - Emax Simon series 25 amp
props - 8x4.5 Emax

%125?
%150?
%200?

impossible???

 

[JUSS10]

Here is mine. I built it from spare parts laying around from a mini guinea that hit the ground hard. 5g servos, not exactly sure on the motor, 6x4 prop, 3s 900ma that I got from the 3DR clearance sale, and lemon rx 6ch rx. The 3s just fits, and the rest of my zippy 1000mah 3s packs wont. if the center section was just a bit wider it would have fit fine.

I redrew the plans in cad and cut them on a laser. I may try and change the plans for a wider center section for a slightly larger battery.

We have a fair bit of snow here in michigan so I need to water proof it or wait till spring. I'll likely paint it up this weekend and give it a try.

 

[xMeox]

here's the parts i have access to (obviously 4 each on the motors, props, and esc's)

3300mah 3c
motors - Emax grand turbo 2213/935kv
ESC - Emax Simon series 25 amp
props - 8x4.5 Emax

%125?
%150?
%200?

impossible???

I would increase the size as much as you need to fit the battery. I doubt that you will get unlimited climb with that motor/weight ratio but it still should be flyable. I think that doubling the size will push the motor to its limit.

 

[nevenelestate]

so how big of a deal is it to monkey with the dimensions until it will carry a 3300mah 3c?

You can always try increasing, or decreasing by whatever you want, the only issue becomes A and B folds. The drawings are setup with 5mm gaps, if you do 150% then you will have 7.5mm gaps. It just takes some thinking on your part to figure out which side of the gap to make smaller, and in some spots the other dimensions that are near those gaps can need to be adjusted. It is not as simple as increase the size and print, but it is fun to do. I have shrunk the versa wing and explorer, as well as 120% increased the Mini Guinea. I might even try a shrunk down version of this plane

 

[octodreamerFNG]

You can always try increasing, or decreasing by whatever you want, the only issue becomes A and B folds. The drawings are setup with 5mm gaps, if you do 150% then you will have 7.5mm gaps. It just takes some thinking on your part to figure out which side of the gap to make smaller, and in some spots the other dimensions that are near those gaps can need to be adjusted. It is not as simple as increase the size and print, but it is fun to do. I have shrunk the versa wing and explorer, as well as 120% increased the Mini Guinea. I might even try a shrunk down version of this plane

yeah i knew the folds (or the material) would need to be adjusted, but i think there's more...

the servo cutouts need to be preserved, the camera window, maybe a few more things i'm not thinking of... but all the other basic sizes of the actual frame dimensions would all change int he same scale and it should still fly?

makes me wonder if after a certain size the foam board isn't enough to support itself...

i'll have to mess around with it and base the change off how big the battery tray needs to be to hold this 3300mah 3s brick i'm stuck with.

 

[nevenelestate]

makes me wonder if after a certain size the foam board isn't enough to support itself...

The Kraken is around 6ft wing span, I believe, so you would really need to increase this model by a lot more than 150%. As long as you have the spar built properly it should be plenty strong.

Of course as you noted some of the things like the camera hole would need to be one off built. ore importantly is the motor pod. For the motor pod you could build your own firewall out of 3/32" birch ply wood, I did that for my enlarged Mini Guinea. The camera hole and things similar to that would be easier, just print a 100% set of plans and use that hole size to cut out the front hole.

The flight qualities will likely change. If you watch the video from the Mini Guinea build they discuss how it took them several down sizing attempts to find the best performing smaller size of the Guinea Pig. This also just depends on how much your personal preference is to having a perfect flying aircraft. I tend to find the "good" in anything I build and fly, whereas someone else might say some of the experimental modified designs I have tried are "un-flyable". All personal preferences.

 

[dayve]

Like a few others I see on here, I'm planning to run my 1000mah pack in the Mini Arrow. The stock pod is about 31mm wide. From a brief look through battery sizes online, 1000-1300mah packs usually run about 35mm wide. I used my meager Inkscape skills to redraw the pod and hatch plans to accommodate this.

I'm going to try out my plans this weekend. I'll post them here now in case others are building this weekend and want to try them out, too. Since DTFB is 3/16" thick, I added 3/8" (which is about 1cm) to the total width of the pod.

If you use these plans, keep the following in mind:
1. I haven't tried them yet, so use at your own risk.
2. The stock power pod should still work if you put a piece of foamboard on each side as a spacer.
3. You'll have to change the wings somehow. Either:
- cut more out of the top surface. I think this will cause the leading edge to not meet up with the front corners of the pod.
- use a 3/8" spacer between the wing halves on the bottom. This will increase wingspan and maybe change flight characteristics???
- come up with your own solution

Feel free to use/modify these as you wish. Thanks to Sp0nz for providing the excellent plans for me to hack on.

View attachment FT Mini Arrow Widened Pod v1.0.pdf

 

[Aeronaut]

yes please tell us how it flies with a 2200 I would love the longer flight times if I could get them.

 

[bhursey]

Seems heavier and slower if you up the battery? Wouldn't it be better to just get a bunch of 3s 800s, and just have them charged ready to go and rotate them?

 

[Aeronaut]

I have a lot of 2200 and 1500 batteries i could just use the 1500 but I like having flexibilities. and Im cheap

 

[paultbg]

Mine was built from 6mm depron, minimal tape reinforcement, 9gr servo, 1000mAh 3s zippy all add up to 350gr... a bit fatty, like the owner

 

[WombatControl]

so how big of a deal is it to monkey with the dimensions until it will carry a 3300mah 3c?

i've got a bunch of useless parts from the old knuckles quad + laser toys power pack that i could never get to work... wondering if i can adjust the scale of the plans on this until it'll work.

here's the parts i have access to (obviously 4 each on the motors, props, and esc's)

3300mah 3c
motors - Emax grand turbo 2213/935kv
ESC - Emax Simon series 25 amp
props - 8x4.5 Emax

%125?
%150?
%200?

impossible???

Possible, but not a good idea. You can maybe get it to fly, but wings like higher KV motors. They need a smaller prop spinning faster than a standard aircraft. So 935kv is not going to give you good performance for a wing. Generally you want at least 1200kv or faster. A multirotor needs its motors to provide thrust for direct lift. A wing needs speed over the airfoil and control surfaces to generate lift.

Rather than trying to scale up the Arrow plans, you may have better luck trying a design intended to be larger. Carrying a battery that large may require something like a blunt nose Versa.

 

[localfiend]

Possible, but not a good idea. You can maybe get it to fly, but wings like higher KV motors. They need a smaller prop spinning faster than a standard aircraft. So 935kv is not going to give you good performance for a wing. Generally you want at least 1200kv or faster. A multirotor needs its motors to provide thrust for direct lift. A wing needs speed over the airfoil and control surfaces to generate lift.

Rather than trying to scale up the Arrow plans, you may have better luck trying a design intended to be larger. Carrying a battery that large may require something like a blunt nose Versa.

To add a slightly different opinion. I ran a 2213 935kv motor on my Versa Wing with a 8x4.7 SF prop on 3s in pusher configuration and it flew beautifully. Did the same thing, the motor was pulled off of a quad. Heck, I even used 3300mah batteries, as that's the size I was using on my quad copter at the time.

Loaded it up with light FPV gear and flew it to death.

So yeah, a wing will do just fine with those electronics, but you might be better off just building a Versa as Wombat suggested instead of upscaling the Arrow.

 

[Sneeky7]

Well the center cavity between the wings needs to be opened up when you build because it ends up slightly pinching the pod for the battery hatch. My battery compartment is too small to hold any of my batteries, even my 800mah 2S. It's just not wide enough.

When Josh builds his in the build video, you can see how it gets pinched. To hold a battery I ended up putting velcro on the outside top.

 

[Sneeky7]

 

[brettp2004]

Did that fly very well with the 2200mah on it? That seems like a lot of weight for that small wing. Have anyone built one with Power Pack F yet? What kind of flights times are you getting with a 800mah?

 

[dayve]

I just built and maidened mine. I used the wide pod modification that I posted above, so my 1000mah 3S would fit in the nose. This also gave a nice clearance for the 7" prop. My prop cutout is 7.5" wide now.

When I was cutting each of the wing shapes, I added a 3/16" strip along the center, bottom edge(the edge where the wings join together) since the pod is 3/8" wider than stock. This made everything else work out perfectly. There's no gap underneath the pod. The leading edge of the wing lines up where it's supposed to on the pod.

Lesson learned: Don't maiden a white wing on a cloudy day with snow on the ground. I'm going to paint one wingtip a bright color so I have a hope of keeping orientation.

 

[Sneeky7]

Did that fly very well with the 2200mah on it? That seems like a lot of weight for that small wing. Have anyone built one with Power Pack F yet? What kind of flights times are you getting with a 800mah?

Nope, pretty anemic, and that's just an MT1806 with an APC 6x4E. Took it up, turned around, and came right back. The thing is, my Venom 2S 800mah batteries are even too big. They're too wide. Kinda bummed to be honest.

 

[Adam Enggasser]

Anyone know what 3 blade prop was used in the FT intro video? Not sure what benefit that would have besides a decrease in diameter, could someone please explain that also? Any help would be greatly appreciated!

Looking forward to building one of these in the next couple weeks and outfitting it with FPV gear!