Wow, that is quite a saving, congrats!
Your thrust to weight ratio potential is other-worldly. Upwards of 12:1 on the Sunnyskys?

Madness!

I'm running the Emax 1804s on this frame not the Sunnyskys. Thrust to weight is about 7:1 on 3S

I've had the chance to run a few packs through the X4 now.

The Pico BLX is running the latest Betaflight 2.8.1 and took me a little while to tune in the rates and expo to my liking, removed the Superexpo feature. I'm not really a fan of it, much prefer a linear stick feel towards the extremities.

The reduced weight has a pronouced effect. With the same motors and props (5x3), the initial punch is a step better, the lack of inertia is also really felt when flicking around tight turns. Didn't feel too floaty, which is one thing I thought it might.
The standard yaw rates in 2.8.1 are a lot higher than what I'm used to, which I've left high. I've been meaning to try out quicker yaw rates after some flying tips over on the Warpquad thread. They're definitely growing on me now, adds to the nimble, flickable feel to the quad.

It's taken a few decent hits into the lawn, no snapped arms yet..... but those 6mm arms do look spindly and vulnerable. For the sake of another 4 or 5 grams, my gut feel is that 8mm is a better choice.

I'm having problems with math, lol. U180 is 180mm m2m, and warpquad 200 both run 5x3 props, when I do the math it seem like the props should hit.

You indicated you need x arms to be 250mm for 5" props. Without any overhang can you do 200mm?

200mm motor to motor gives you 15mm clearance between the prop tips with 5" props. I used 250mm pieces for the arms (a little less on the X4) as I wanted some overhang of the arms to protect the motors.

I've put quite a few packs through the superlight custom bonded tubular X4 Raptorcopter now. On 5x4 props, the punch pretty much matches my 230 Warpquad on 3S with 6” props and it certainly gets a shift on when wound up. The lack of inertia really increases the manoeuvrability and keeps your thumbs sharp. The Warpquad feels like a heavy beast when flown back to back

Anyway, I've just had the chance to try out some 4x4.5x3 DAL props - nice improvement for smoothness and feel, less floaty, still super nimble and really quiet as well. The punch isn’t as good however, as expected, can't quite decide whether I like the less floaty feel or not.

It does look a little disproportionate with 4 inch props but on the plus side they keep the thrust out of the way of the ESCs, so just have the circular 6mm arms to contend with. Battery life was only a little down.

If the punch was the same they’d be a winner. I'm now thinking 4S with these props could be the ticket...

Originally Posted by TimR74

I've had the chance to run a few packs through the X4 now. ..

It's taken a few decent hits into the lawn, no snapped arms yet..... but those 6mm arms do look spindly and vulnerable. For the sake of another 4 or 5 grams, my gut feel is that 8mm is a better choice.

You could tension some spectra zero stretch fishing line around the perimeter. Imperceptible weight, yet 15x stronger than steel.

Originally Posted by sonic_boom

You could tension some spectra zero stretch fishing line around the perimeter. Imperceptible weight, yet 15x stronger than steel.

...nice idea for increasing lateral strength.

Originally Posted by sonic_boom

You could tension some spectra zero stretch fishing line around the perimeter. Imperceptible weight, yet 15x stronger than steel.

I like that idea, trying to think if how best to connect all 4 arms and also tension it equally.

Is the epoxy bond really strong enough for those motor mounts and center plates without worrying about breaking during the most extreme of manuvers?

I've been building my own DIY frames . They are Warthox style, 4-5mm G10 arms sandwiched between .80mm G10 all held together with 3mm screws,washers, and locknuts. Done all sizes through the years,

Just build a 250 size with 2208 2300kv motors 5x4.5 BN props, 30A Sunrise Cicadas blheli_s ESC's powered by 4s1300mAh 65C graphenes. Talk about a rocket! Its unbelievable, especially with the new battery and ESC tech. I can only imagine if I shave weight with a frame like this.

Originally Posted by Ari33

I like that idea, trying to think if how best to connect all 4 arms and also tension it equally.

Continuous perimeter, 1.5 -3 loops around each arm outside of the motors. Truckers hitch and lock off with a few half hitches.

The only downside is it's more likely to get caught in a tree than a pure x frame

Originally Posted by chrisbarth

Is the epoxy bond really strong enough for those motor mounts and center plates without worrying about breaking during the most extreme of manuvers?

I've been building my own DIY frames . They are Warthox style, 4-5mm G10 arms sandwiched between .80mm G10 all held together with 3mm screws,washers, and locknuts. Done all sizes through the years,

Just build a 250 size with 2208 2300kv motors 5x4.5 BN props, 30A Sunrise Cicadas blheli_s ESC's powered by 4s1300mAh 65C graphenes. Talk about a rocket! Its unbelievable, especially with the new battery and ESC tech. I can only imagine if I shave weight with a frame like this.

Epoxy is way way strong, and the loads are relatively low. No fears there, you could always reinforced with carbon tow, but no reason to do so.

Originally Posted by chrisbarth

Is the epoxy bond really strong enough for those motor mounts and center plates without worrying about breaking during the most extreme of manuvers?

I've been building my own DIY frames . They are Warthox style, 4-5mm G10 arms sandwiched between .80mm G10 all held together with 3mm screws,washers, and locknuts. Done all sizes through the years,

Just build a 250 size with 2208 2300kv motors 5x4.5 BN props, 30A Sunrise Cicadas blheli_s ESC's powered by 4s1300mAh 65C graphenes. Talk about a rocket! Its unbelievable, especially with the new battery and ESC tech. I can only imagine if I shave weight with a frame like this.

The epoxy bonds are stronger than they look. Trick is proper surface preparation and the use of slow 24 hour curing epoxy. I'm yet to test it out for bigger, heavier frames yet tho.......

Chris - do you have any photos of your DIY frames? Your 250 sounds like a beast!

I've been loving the 4 inch props on the X4 quad. The DAL TJ4045 triblades are certainly lacking in punch compared with 5030 props, but they make up for it in smoothness and response. Don't think I'd trade them in and go back to 5” on this frame. It's less floaty, but the quad is really light anyway, maybe too light for 5” props. The increase in precision, especially noticeable in the wind, makes it even more nimble enabling harder, more aggressive flying in a restricted backyard space.

To gain that punch back, I've splashed out on a few 500mAh 4S graphene LiPos. Hope there prove to be worth it as they're pricey for small batteries. Also ordered some DAL T4040 bullnose triblades and T4045 V2 triblades for some further prop experimentation.

As 5 inch props are not currently getting a look in for my backyard flying now, it's sparked my enthusiasm for building a 3” LOS quad for my next frame, which I had initially thought was just a little too small.

Rough plan is a 140ish mm frame using 6mm, 0.5 mm wall thickness, tubes. Hopefully should be able to hit a weight of around 10 grams......

Sure, heres a larger version of the same design I did a while ago.https://www.rcgroups.com/forums/show....php?t=2406048

This was about 450 size. All done freehand with a Dremel diamond disc and a 1/8" carbide burr. Old carbide table saw blade used to cut the straights, it dulls fast so I use the Dremel diamond disc again to sharpen the blade! Love those diamond discs!

Yes, I totally ripped off Warthox. No shame, but hey its a great design. Only so many ways to make a X.

With the 250 the total AUW is at 500G. This is with a 1300mAh Graphene. I suppose its heavy IDK, but its super tough. I'm rewinding one motor that burned on me after the prop broke while doing a full throttle inverted dive. Yes, not smart! Anyway, it was pretty high up when the prop broke and came down spinning but still carrying a lot of speed, it slammed into every branch of a really tall popular in back yard/woods.

It took some "foxhunting" to find it using my FrSky RSSI as a tracker. I eventually found it, not one thing broke except for the burned motor! I'd imagine it would fare worse in the winter. Now the bushy treetops leaves probably bled a little speed/energy.

Originally Posted by TimR74

I've been loving the 4 inch props on the X4 quad. The DAL TJ4045 triblades are certainly lacking in punch compared with 5030 props, but they make up for it in smoothness and response. Don't think I'd trade them in and go back to 5” on this frame. It's less floaty, but the quad is really light anyway, maybe too light for 5” props. The increase in precision, especially noticeable in the wind, makes it even more nimble enabling harder, more aggressive flying in a restricted backyard space.

Good feedback on the TJ4045 tri-blades, Tim! I've had a stock of various 4" props for ages (dual blade only), but still haven't tried any of them. In my defense, I've been living out of a suitcase, and all my quad stuff is packed in boxes. So no RC flying for me at all right now. Looking forward to a more settled life back in the US soon.

To gain that punch back, I've splashed out on a few 500mAh 4S graphene LiPos.

You're more courageous than I am! For the time being, I'm sticking with 2S and 3S for LOS acro. More than enough challenge for my basic skill level.

As 5 inch props are not currently getting a look in for my backyard flying now, it's sparked my enthusiasm for building a 3” LOS quad for my next frame, which I had initially thought was just a little too small.

Rough plan is a 140ish mm frame using 6mm, 0.5 mm wall thickness, tubes. Hopefully should be able to hit a weight of around 10 grams......

Looking forward to it!

Might be worth trying RX1102 8000KV motors on a 10g light frame. I have some 3" and 4" builds in the works as well, once I get settled down again. Really looking forward to more sub-250g micro brushless action in the second half of this year!