Everyone probably knows APEX 5. I built it about a year and a half ago in the HD version with ELRS. It's my absolute best 5inch, hands down, it flies amazing, the only limitations are hands and brain. But you can't fly far with its original equipment. I also immediately bought spare parts for the APEX 5 so that I can fix it right away if needed. I also built a true LR quad, the FR7 HD. It is amazing, it flies basically like an airplane, it can last even 25 minutes in flight, but for that it needs a capacity of 8 to 10 Ah composed of 2x6s4000 or 2x6s3000 and 1x6s4000 Lion battery. The weight of the quad is huge and the quad is definitely not one of the agile ones.

Well, I recently discovered the iFlight Bob57, which combines agility and semi LR in a good package. I haven't used the spare parts for the APEX 5 and they have been in the drawer for a long time, so I thought I would build an APEX 6 LR HD, which will be able to fly quite long with only one 6s4000 Lion battery that I already have for the FR7. I ordered 6 inch arms and slightly bigger motors, everything else important was in the drawer. That is, almost everything, except for the necessary TPU parts that will be needed for the LR, and which I have already partially designed and printed for the FR7.

So I started by designing and then printing all the necessary TPU parts. I only used the camera lens protection from the original APEX 5, the rest is completely new. The LR quad doesn't need skids, but rather needs protection for the arm ends and motor bolts. So I designed slip-on guards that would be light and do the job. The motor will be attached with only three screws, the one closest to the body will hold the guard in place by the side of its head. And I used the stripe design I had previously chosen for the FR7. For LR, a diversity receiver is really necessary, and the antennas should be polarized horizontally in the front and vertically in the back. So I designed a front mount for the ELRS balun dipole antenna (BetaFPV) that would fit in and not be completely hideous. The antenna will be inserted into the holder from the side and protects both the body and the cable of the antenna.

Unfortunately no one is still making a good ELRS vertically polarized antenna for the LR, so I remade the antenna I made for the FR7, just a bit shorter. Instructions are here.

https://intofpv.com/t-elrs-long-range-an...#pid170721

I didn't want to use an AirUnit and two VTX antennas because of the weight, so I chose Vista with one VTX antenna. And I decided to place the VTX antenna and the RX antenna next to each other as easily as possible, so I made a rear mount for vertically polarized antennas that fits on the APEX butt. The holes for the antennas are slightly angled apart. Of course, a GPS module mount is needed, here I rely without a doubt on the Matek M8Q, which has proven itself very well with the fact that I do not activate the magnetometer. I designed the rear antenna and the GPS mounts as split, so that they could possibly be replaced with a triple version of the antennas without the need to print the GPS holder part. The mounts slide on top of each other and cover the entire height of the standoff.

I initially flew the Apex 5 with a stock Hero 8. Later I made the Naked Hero8 which weighs about 27g including the ND filter and microphone and put it in a temporary TPU case on the Apex 5, saving almost 100g of total weight, which is a hell of a lot, and the Apex 5 flies all the better. Later I made a new TPU case which can be seen in the first message of this thread. Significantly increases the durability of the Naked Hero8, so far it has survived unscathed. Since the camera is much lighter, the APEX 5 has the case for the Naked Hero8 moved further back due to the center of gravity, so everything is really centered. APEX 6 LR will have a battery that weighs 400g and is relatively large. The case for the Naked Hero8 thus needs to be moved further forward and a bit higher to keep the 6 inch propellers out of the camera's view to maintain a good CG position. This case takes about 8 hours to print...

Oh, and I have got new motors. I chose exactly those that are used in BOB57 - Xing2 2506/1500kv, ideal compromise for a 6-inch, which should be a bit efficient rather than very powerful, but still very agile and responsive. I managed to screw them onto the 6inch arms, I'm saving, I only used 3 screws. Since I will be mounting extra things under the lower frame plate, I am raising the arms up with 3M foam feet.

I also printed the buzzer mount, without which the LR quad is hard to find, and started putting it all together. There is no more room for the buzzer in the frame, so I put it under the rear bottom plate, where its face is partially protected by the front bottom plate. I used already proven FC Mamba F277 App Mk4 which has a built in VTX switch, I really appreciate it. It is possible to turn off Vista and calmly wait for 3Dfix without overheating Vista if you need to wait a little longer. It also has wifi, but it didn't work at all for me, it takes a long time to connect to the smartphone and the SpeedyBee. In my opinion, wifi is useless, I use a USB - OTG cable from a smartphone and it works quickly, reliably, and I don't have to connect a battery, this is without question the better solution for me ...

As an ESC, I used the proven Mamba F55 128K, which can be set with a PWM change from 24kHz to 128kHz depending on the motor rpm. I mounted the Vista in place on 3mm standoffs, the wiring is routed under the Vista and hidden. Matek GPS is nicely covered with its holder, there are grooves in it so that both LEDs indicating GPS status can be seen, the holder for the rear pair of antennas is slid onto the GPS holder.

I mounted the ELRS antenna in the front holder and put on the arm end guards. It's going well so far, it's starting to take shape... hopefully it'll be done tomorrow.

Ok, I'm done. It was quite a lot of work, I won't go into any further details. BF 4.3 is set, default PIDs and my rates. If anyone is interested in anything, be sure to ask. In the end, I really like it, what do you think? On the fact that it is from leftover spare parts. 

It doesn't even look much smaller next to the FR7.

Hmm, the battery straps are short, I replaced them with longer ones and extended them even more. The Molicel P42a 6s4000mAh 21700 on the top plate ... CG is exactly in the middle, I am satisfied. 

I managed the first VLOS flight, only in an underground garage. It was almost dark outside and it was raining, again...
I made a video, I will post a link later. It flies great, everything went really smoothly, I'm already looking forward to the first LR flight. It is both stable and agile at the same time, it is hard to describe, you have to fly with it, hopefully you can see it on the video. But what got me is the flight time, the video only shows the beginning, but I flew like this for the whole 28 minutes! I did not expect that, I landed at 3.0V per cell, after disconnecting the cells showed 3.25V, so they were not completely discharged, I estimate that there will still be at least 200 mAh in them. I charged about 3720 mAh so I will finish calibrating the current sensor.

Those 28 minutes got me. If it goes sharply outside, I don't expect a flight duration shorter than 18 minutes, and that's great. And if it's just cruising, 23 minutes will be realistic.

Very good! Send it out and see what she can do.

Fantastic build thread. Thanks for sharing so many photos and so much detailed information.

I'm glad you like it. Hope this helps or inspires someone.

I am currently switching to the HD version of MSP-OSD including changing the fonts in DJI fixed parameters in Goggles v2. It's quite a journey...

It's worth it mate, the HD OSD is much better and using custom fonts really make up for the size in HD.