200% Spitfire - Build Log

[nerdnic]

I'd go with a 1000mah RX battery at least. The servos you linked are power hungry little beasties.

I've only used an ESC that had a BEC at this point so I'm not sure how to best approach needing additional power for servos. If I have a 1000mah battery would I still run it through an external BEC or just go straight into the receiver? I guess my overall question is if I'm using a second RX battery, do I still need a BEC or is the BEC normally tied back into the main battery?

 

[Foam Addict]

Run the aux battery through a 5 amp+ BEC, and pull the red wire from the ESC to the receiver. That should work nicely with about a 1 amp to spare over the max servo draw.

I hope this helps, I've never been quite so ambitious with a project like this!

Great job so far!

 

[EraJomppa]

This will be my first really big plane but I have made 1300 and 1500 size before. That motor would have plenty of power but it's too high kv. The things you want to keep in mind are prop size and thrust. A DTFB plane is going to be a lot lighter than any RTF kit so you don't need nearly the thrust but you still need a big prop to get air around your fuse. For a 1500mm I would not go smaller than a 12" prop, which at 3S puts you probably around 1000kv and 8-900 kv for 4S. You'll want a motor in the 600w range that can swing a 12" prop for pretty decent scooting around. 800-1000w would give you sport performance.

This is the motor I'm using for my 1500mm Corsair with 4S and a 12x6 APC
http://www.hobbyking.com/hobbyking/...0KV_815W_US_Warehouse_.html?strSearch=Ntm 900

EDIT
After looking at some of the test data in the comments a 12x6 on 3S seems to work with the motor you linked. So I'd say go for it!

That is very encouraging to hear.

Yea, I know the reason for wanting to use a bigger prop. The plan would be, as you described, to use 3s (2x 2200 mAh in parallel) and swing a 11" or maybe 12" (I got a lot of 11x5.5 props around). But I'd much rather use a bigger 650 kv motor with a 4s and 14" prop. A bit slower prop speed and more thrust (rather than more prop speed and less trust like the 1300kv motor), it would bring more scale like qualities to the flight and slow things down a bit and give more thrust rather than top speed when you need to get out of a bad situation.

Thanks, back to the topic

I'v seen people use as big as 2200 mAh receiver batteries on big planes. But that might be overkill
I just personally don't like to hassle with 2 batteries and I try to use a big BEC for example when I use more servos. Also for FPV stuff I rather take the servo voltage and boost it to 12 V rather than use a separate battery (or separate BEC) for the FPV gear. But I haven't really build anything this big so different kind of forces might be in play.

 

[nerdnic]

Run the aux battery through a 5 amp+ BEC, and pull the red wire from the ESC to the receiver. That should work nicely with about a 1 amp to spare over the max servo draw.

I hope this helps, I've never been quite so ambitious with a project like this!

Great job so far!

Thanks! Normally I wouldn't take on something like this either but I figured why not!

I'll need to order some more batteries as I only have the 350mah 2S shown in the photo. Do you think it's just an issue of the battery draining too fast? They should be able to put out enough amps.

 

[nerdnic]

That is very encouraging to hear.

Yea, I know the reason for wanting to use a bigger prop. The plan would be, as you described, to use 3s (2x 2200 mAh in parallel) and swing a 11" or maybe 12" (I got a lot of 11x5.5 props around). But I'd much rather use a bigger 650 kv motor with a 4s and 14" prop. A bit slower prop speed and more thrust (rather than more prop speed and less trust like the 1300kv motor), it would bring more scale like qualities to the flight and slow things down a bit and give more thrust rather than top speed when you need to get out of a bad situation.

Thanks, back to the topic

I'v seen people use as big as 2200 mAh receiver batteries on big planes. But that might be overkill
I just personally don't like to hassle with 2 batteries and I try to use a big BEC for example when I use more servos. Also for FPV stuff I rather take the servo voltage and boost it to 12 V rather than use a separate battery (or separate BEC) for the FPV gear. But I haven't really build anything this big so different kind of forces might be in play.

I think an 11 will still work if that's what you already have available. For my BEC battery I could use a big one if needed, I am thinking the plane will sit around 8lbs or so and my motor puts out 16lbs of thrust so I have a little wiggle room for these extras. I guess I just need to figure out what kind of servo/RX run time I would get out of the difference mah capacities to see where I want to land. But I have no idea how to figure that out.

 

[nerdnic]

Updated 1st post - spar and landing gear are done!

 

[airhawk]

i would give it some more reinforcement on the wing after what happened to David's 200% spit

 

[nerdnic]

i would give it some more reinforcement on the wing after what happened to David's 200% spit

I agree, he was just running doubled up foam spars. Do you think the addition of the aluminum spar is not enough? I run a scaled down version of this on my other planes and the wing has 0 flex, it's crazy strong.

 

[Christopher14]

The aluminium spar is MUCH stronger then a foam spar. You are going to be fine.

 

[nerdnic]

Updated 1st post - wing, tail poster board, servos and control rods/horns are done.

 

[Don_D]

Are the plans still available? Clicked the link in the first post and Dropbox responded the file could not be found or was moved or deleted.

Found the plans and downloaded the 8 pdf's.

 

[nerdnic]

Are the plans still available? Clicked the link in the first post and Dropbox responded the file could not be found or was moved or deleted.

Found the plans and downloaded the 8 pdf's.

Sorry about that, I'm not sure what happened but I have updated the plans link.

 

[SnowRocker88]

Wife for scale!
View attachment 25266

Hey, I saw this pic on Instagram! Haha, cool project!!

 

[nerdnic]

Haha! Yeah I posted it on my Instagram

 

[aldalo]

Does anyone know what size the dihedral gauge is for 200% Spitfire ?

It's 100 mm in the original

 

[nerdnic]

I don't think it came with one. I just eyeballed it and called it good. I've built many Spitfires ranging from a lot to no dihedral and to be honest.. they all flew the same. But the ones with extra dihedral looked funny in the air so I fly now with very little dihedral on both my full sized an 800mm Spitfire.

 

[aldalo]

So here's my Monster Spitfire
I'm concerned about the way I've mounted the motor. Do you think it's too far foward ? ( David's build, motor is behind
the firewall - in the box ) I'm worried about the CG


I don't have the motor box mounted to the fuse yet. Motor weighs appx. 220 grams

Thanks, Alan

 

[nerdnic]

If you can move the motor box deeper into the fuse I would, this will help protect it a little. I wouldn't worry about balance as much, though. What size battery are you using?

 

[aldalo]

4s 3700 25C
weight appx - 375 grams

 

[nerdnic]

Hmm, that is a tad small battery. You might have issues getting enough weight forward. The spit is a pretty tail heavy design.