I enjoyed getting back into the 250 class so much with my Chameleon build that I decided to let go of my only other 3 inch to fund a backup 250 quad.  I really appreciated the thought that went into the Chameleon frame and am generally a big fan of Armattan but I really wanted to try something different.  I never really gave these bus style X frames much thought and certainly don't gravitate to removable arms.  Until I started noticing how many pilots whose skills I really respect swear by the ImpulseRC Apex frame.  Even still, I didn't think it was that good of a looking frame until a salesperson at a local drone shop showed me a completed build.  I was impressed by how it looked.  So I decided screw it and pulled the trigger ...

My biggest concerns:

• Would there be room for a Byte Frost VTX.
  
• This frame was very much designed to accommodate a KISS platform.
  
• Thin racing arms don't leave much room for individual ESCs.
  

It would turn out all of these concerns were well founded.  I will get into these issues as they rear their ugly heads throughout the build.

For starters, a size comparison against the only other 250 class I have, the Chameleon.  When I first saw this in the shop, what struck me was how small it looked.  Technically it has a bigger MTM than the Chameleon at 225 vs 220.  My sense is the thin racing arms is what gives it the illusion of being smaller.  The Chameleon's arms look like they are on steroids in comparison ...



A frame characteristic that kinda rubbed me the wrong way was how the main stack mounting screws are covered by the arms.  This means you need to assemble the stack before assembling the frame or secure the stack from the nut up top - assuming the screw won't turn along with the nut.  I'm not sure I subscribe to this concept ...



With that said, I was impressed by the arms locking mechanism.  These things aren't going anywhere ...



Dry fitting the stack shows there's decent room.  I'm using a 4mm spacer under the FC and a 6mm spacer under the Byte Frost.  But the astute among you will also notice how close those standoffs are to the ESC pads on the Kakaute F7.  This would prove to be highly annoying later ...



And then the individual ESCs ... I went out of my way to find the thinnest I could find for this 6S platform and these Holybro ESCs still were wider than the arms.  You really need to get it to 10mm wide.  Spedix makes fancy thin 40A ESCs that are 9mm wide.



The camera cage is held in place by the orientation of the hex standoffs and pressure between the top and bottom plates.  I generally frown upon this type of camera cage since those carbon fiber tabs can and will wear over time with every removal and replacement of the top plate.  Also, securing the standoffs becomes an exercise in patience since they need to face a certain way to securely hold the camera side plates.  Too much reliance on things that are iffy to secure the camera in my opinion.



Dry testing the electronics ... pro tip ... solder the BEC jumper *BEFORE* you put everything together lol wow that sucked.




Here you can see how the ESC pads on the Kakute are blocked by the standoffs - both front and back.  And you cannot forego those front standoffs since they secure the camera.  (You could probably get away without the rear blocking standoffs ... but that aint how the House of Ronin rolls yo lol.)  The saving grace here is the holes to the openings of the camera plates which allowed me to thread the ESC wires through.  But these I don't think are for ESC wires but rather for the USB port for KISS OSD or something rather.



More for my own benefit for future reference than anything else ... my wiring.



And now let's go through the layers.  Here is the first layer.  You can see how I really had to wind the ESC wires around those ill placed standoffs.  I know most people swing the wires to the inside, but I do not want a nest of wires building up between the FC and Byte Frost since the VTX tends to get extremely hot and will lower its own power because of that heat.





There is a 20x20 rear stack area which I very much appreciate.  I've taken to using that rear area on frames to house the Crossfire Nano and Matek 9v reg ...





While I appreciate the 30x30 form factor of the Byte Frost (particularly in comparison to DJI's odd Air Unit shape), it really is a cumbersome VTX to install with its overall footprint.  In particular, the antenna connector which extends so far out the back.



I'm going to take a moment to rant a little bit about the choice of hardware.  This frame uses a lot of countersunk screws.  While I get why the main stack M3 screws are countersunk so the arms can press up against them, I don't get why the rear 20x20 screws need to be countersunk as well?  The reason this annoys me is because I like using my own M2 and M3 button or socket head screws which I typically cut down to size.  In addition to countersunk screws, there are top threaded socket heads, those black plastic coned doohickeys in the pic below ... this frame very much wants you to use their specialized hardware.



I thought I would have much more room than this both in the rear and in front but it actually ends up being a really tight space ...









I'm a bit surprised also that the top plate is not more GoPro accommodating.  What with all the added plastic components, I would have thought they would provide some sort of plastic GoPro mount as well.  I ended up having to print two separate pieces for my GoPro mount since the single piece designs were just asking too much from my aging Printrbot.  So I printed a couch separate from a Session case.



I recycled a similar design I made for the Chameleon tail antenna mount for use on this Apex frame ...



Money shots incoming ...









All in all I do like this frame despite my gripes against it.  I would recommend an Armattan (any of them honestly) frame over this any day.  Those frames have so much thought put into them and they go out of their way to accommodate various styles of and platforms of builds.  This Apex frame is very much designed for KISS platforms with 4-in-1 ESCs.  I knew that very well going in but I didn't think it was *that* focused.  Well it is LOL.

I did get a chance to fly it but it gets dark so early here, I literally could not see lol.  I have some electronic issues to iron out - the Crossfire was not powering up unless I pushed on it lollll no bueno.  Also I got lazy and copied the CLI diff from my Chameleon to this Apex and walked out the door lol.  Hey I figured same FC, same motors (sorta), same amp ESCs ... no problemo, recycle the PIDs!!  Not so much haha.  It felt like it kept wanting to fly west and my rates feel handicapped.  So I will need to revisit the tune for sure.

Nice build!

I've got to admit - it makes me glad I went with a second Reverb for my backup quad ;-)

Nice one man. Looks good.

Deal

Banelle, I actually had my eye on the Reverb before deciding on the Apex. I figured they would have improved on things which I'm sure they did but in retrospect, the Reverb may have been the better choice for my particular build.

I should caveat that I haven't really had a chance to fly this frame yet aside from two packs hastily flown at dusk. Once I get it tuned, I expect some pretty stellar flight performance. I should also add that there are a lot of positives to this frame package including the massive amounts of spare hardware provided, injection molded (not 3D printed) plastic parts, and even filing tools should you decide you are not happy with the carbon fiber edges (which I was fine with).

It's just its focus on KISS / Mr Steele build that put me off a bit. Again, I knew full well that this was a KISS focused design but I didn't think it was that exclusive. It's like Tarantino's latest film Once Upon A Time In Hollywood where you've got a select group of movie buffs that can only truly enjoy the film. It's a good movie - but unless you are "in the know," you won't fully appreciate it.

Nice build!
I'm so interested on the 3D printed piece that holds the T antenna, what's the name of it?
and more important, can it b printed on regular PLA with decent performance? I have an Iflight XL5 frame

Thanks CM I made some changes to the tail mount design so it aims up more. If you want it, I'll post it up on my Thingiverse and post the link here. But you really ought to print this in TPU. You could try PLA but the elasticity of TPU is what makes it secure.

So I got to tuning this thing and was amazed how far I could push the P/D and the motors are *still* barely hot. But then I realized that I was getting very high frequency oscillations in my GoPro footage (not in my FPV footage though) so I had to back off. I still have some high throttle jitters in the GoPro footage but I think I'm very close to what I think is a good tune. I'll post up PIDs and a quick video in a bit.

Great looking build, hope i get skills like that some day.

(24-Dec-2019, 09:30 PM)goatfarmer11 Wrote: Great looking build, hope i get skills like that some day.

LOL I say that every day. Thank you man.

(24-Dec-2019, 08:29 PM)the.ronin Wrote: Thanks CM I made some changes to the tail mount design so it aims up more. If you want it, I'll post it up on my Thingiverse and post the link here. But you really ought to print this in TPU. You could try PLA but the elasticity of TPU is what makes it secure.

So I got to tuning this thing and was amazed how far I could push the P/D and the motors are *still* barely hot. But then I realized that I was getting very high frequency oscillations in my GoPro footage (not in my FPV footage though) so I had to back off. I still have some high throttle jitters in the GoPro footage but I think I'm very close to what I think is a good tune. I'll post up PIDs and a quick video in a bit.

Thank you, Ronin, I'll appreciate your time uploading the STL for give it a try! My brother doesbt have TPU here and I'll have to get it quickly before vacations are over, but I'll printed and use it!

Alright guys, after doing a bit more reading, I decided to replace the 35v 1000uf cap at the lipo with individual 35v 330uf caps at each ESC. Personally, I'm not sure it makes such a huge difference. Maybe today's ESC's are pretty good at filtering out noise. I did not do a blackbox comparison because I prefer to actually see the difference in real life (also I'm lazy AF lol).

But I'll let you decide from this comparison video ...



After looking at that video, it does seem that there is slight improvement with the individual ESC caps. But personally while actually flying, I did not notice a difference.

Two big caveats. Obviously I'm using the Byte Frost VTX so I don't know if that system is necessarily more or less prone to noise. If I had to guess, given it is handling far more data than traditional analog, it should be more prone - but don't hold me to that. Another caveat which I don't think ought to make much difference is that I used Spedix 35A ESCs with the single 1000uf cap and I replaced those with Spedix slim 40A ESCs with the individual 330uf caps.



I opted for these slim ESCs so they were more in line with the slim racing arms of the Apex.



Notwithstanding what I felt was little to no change between the two setups, I am sticking with individual ESCs and will likely do so with any future 6S builds. For 4S builds, I'll likely stick to a single cap at the lipo. Also for these 250 class 6S builds, it was getting kinda tight in the back there with the huge 1000uf cap.

Ok ok I admit I like the LEDs too LOL.

Oh and by the way CM, I think I'm good with this tail mount design now so I posted it on Thingiverse ...

https://www.thingiverse.com/thing:4070695



Enjoy!  

(27-Dec-2019, 09:01 PM)the.ronin Wrote: Oh and by the way CM, I think I'm good with this tail mount design now so I posted it on Thingiverse ...

https://www.thingiverse.com/thing:4070695



Enjoy!  

Great! Thank you so much! I'll printed for my iflight frame once I get the TPU an post back!

Hey Ronin, what an awesome build! Reading your thoughts on the Apex, it seems they may have taken a few steps backwards but you certainly made it work .

I have two ImpulseRC Reverbs (6" and 7") and a clone frame I bought for an extra set of 7" arms (they fit with some filing). They are my favorite frames in the mini's as there is plenty of room for everything.

My FPVRecon 210H is my beloved 5", but FPVReconn is long out of business and if I ever have to replace that frame, it will be with another Reverb!

I had to tune this guy again because I replaced the F40 Pro II's with some super saucy F60 Pro IV's. I was dreading this tune based on the headaches I'd been having with my other quads.

Effortless, no b.s. tuning. I really don't know what it is about this frame or maybe mine got sprinkled with FPV unicorn fairy dust by accident on it's way to me, but it has just been a 100% hassle free, super tune-able, sick flying quad for me. So much so I felt compelled to write about it just now.


[edit] I'd add that the Spedix slim 40A ESCs have been an absolute trooper. While my other Tekko ESCs have been throwing temper tantrums now and then, these guys have been spinning whatever motors I throw at it without so much as a murmur.

Saucy ...