X4 v4 build quest

What is the locking mechanism for the legs in v4 for the x4? My kit didn’t include anything? I wish I knew where to find a parts list and more build videos. Thanks!

Welcome to ePPG and X4 ownership.

The leg pivots have holes that align when in fully up or fully down position. The idea is to slide a locking pin or pins through the holes in those pivots. These are not provided with the kit.

I scrounged up some common finishing nails that are just about the perfect size. The head of the nail doesn’t go through the holes, the shaft does. I rounded off the points and cleaned them up.

I then cut a block of thick foam rubber to fit between the pivots. Shoved the nails through the pivot holes, through the foam, and into the holes on the opposing pivot. I used three nails. The foam rubber holds the nails against vibrating out. I check them regularly for security and replace them once a year. I don’t typically fold the legs on mine for transportation so this works really well.

Thought I’d get a pic for you, and check them at the same time.

Two nails from one side the third from the other side. Note the foam block. The odds of all three, or even one, shaking right out during a 20 minute flight… I am comfortable with.

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Thanks Greg. I think my kit is missing more things, mainly the dials that lock the arms in place. A parts list for the kit would be so helpful. Is yours fun to fly? Is it worth it? The missing parts and how long everything is taking has me bummed :slightly_frowning_face:

The twist locks haven’t been used since batch two when I shared a different quick release latch to the forum. However, a latch for the arms is not needed at all. The thrust holds the arms into the forward position and so does the hoop. It’s not possible for the arms to fold back with the hoop in place.

The same is true with the legs if you install the stoppers I designed which keep the legs from moving forward.

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It works! Super stoked.
Flys really well, smooth power, no torque twist, fun to use. Louder at full throttle than expected but great climb and control.
Question- how low v can you run 7s Bonka’s? There’s no low voltage cutoff on the esc correct? How bad is it to run them low? I bought little voltage alarms but just learning. Thanks!

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I recommend not going below 3.5 volts per cell which is 49 volts (7 X 2 X 3.5 = 49). While applying throttle the voltage will sag. The more throttle you give it the more it will sag. If it sags below 49 you should ease up on the throttle till it reads above 49 again. At this point you should be close to your landing zone preparing to land. There is not a low volt cut off system and if you run the batteries to low it will damage them.

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How much you run down the batteries will also depend on your LZ and your confidence.

I never let my 6S Bonkas show less than 43 or 44 (3.5/cell would be 42) volts. But the terrain I fly over demands a bigger safety margin than most. I do not want to be approaching the lz without enough for good climb performance if a go around is needed. I can’t just land short or really long, ever. It’ll be trees or fence rather than just a long walk.

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I dumbed up this morning after a good flight and smoked all four props and a B and a C line.

Looks like it’s time for a prop upgrade. Do you guys have any good recommendations for quieter, better thrust carbon fiber props?


I know this is a week later but i hope your ok!
That sounds bad. Any frame damage? The X4 is pretty fragile. Check it over really well for cracked carbon or broken printed plastic parts.

All looks good except props, ordered new wood from Oppg. What about CF prop upgrades? What have you learned about the best noise & thrust? Thanks!

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I’m still flying stock propellers. There has been some discussion earlier on this forum about efforts to reduce prop noise on the X4. The research is not inexpensive and our usage is pretty niche. Best way to reduce propeller noise and increase thrust, and efficiency, is to make it bigger and spin it slower. Hence the sp140.