Druckbär UL4 6s AUW < 250g

By Nightprowler on Jul 27, 2019

11  615  8

Inspired by a Whatsapp chat with Christian von Druckbär, here is the first result. The maiden flight is still out but here are the first pictures.

AUW = 249.6



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Nightprowler   Jul 30, 2019  

Findings of the maiden flight:

Flown completely stock (Betaflight apart from the changes recommended by Joshua Bardwell regarding Betaflight 4, Runcam Racer Nano etc.)

The first batteries I flew very carefully for testing purposes. At first I thought, the punch could be a bit more but for my flying skills :-) I'm basically satisfied with now eight batteries, even if I had nothing against a little more punch.

Flight Controllers / ESCs:
The setup and configuration was absolutely trouble-free. The quality seems very good. I'm very satisfied. Attention, not real BLheli_32 telemetry but a conventional current sensor on the board (in doubt, even better, because then the consumption of the VTX, etc. can be taken into account.) The specification of the scale is obviously not true., If I 80% of the battery fly according to the display, the battery then has at rest still about 3.7V.

I'm not completely satisfied with the picture and the quality. The enclosed MMCX antenna seems rather cheap. I'll order a lumenier if I can get it into the AUW. The quality decreases with increasing distance or obstacles shrubs / trees very fast. Let's see, so there is still a todo here.

The little girl is doing really well. Even if the stock settings (as known) still need to be adjusted significantly. Even with clear twilight (I flew until 21:15, from 21:45 it is really dark), the cam has delivered an amazingly bright picture, even if this was due to a significant grit.

Battery pack:
GNB 550mAh 6s 80C
GnB used to be good. Batteries after the flight slightly warm, even at full throttle passages stable stable.

Unlike BloodyLordV so far had no problems with the engines. They take the gas well and are only lukewarm with the T5040C after the flight. However, a little more punch would be desirable.

The first battery I flew with the solid Dalprop T5040C. Everything is wonderful. Nice flight picture very satisfied. Engines only slightly lukewarm after the flight.

Then I tested the following biblades:
Race Force 5038 (see Emax Avan S). Very clear vibrations, strong propwash and sounding props especially with increasing throttle (> 85-90%).
Dalprop 5050 biblades. Significantly better than the race force but also sounding props and significant vibration (even in the DVR) at higher gas content.
I think that here a lot about the PIDs would be possible, but here I have to read correctly first (so far flown with stock PIDs).

I will first test more triblades. My favorite props on the UL3 (T-engine 5143) are not here, unfortunately, because the distance is clearly too low and touch the tips. Alternatively, I could probably block the race arms, but again that's a matter of weight.

Flight time:
Compared with the UL3, the flight time of previously approx. 3-4 minutes to about 6 minutes + X. But then there are also quieter passages with it. Cozy flying at the end of the day. The higher the gas content increases, the shorter the flight time, of course, but less than 3 minutes I have not come yet (Attention with the stock current settings, so in the batteries would be enough reserve enough ncoh see above)

Even though there are still some construction sites I am very satisfied with my first 6s UL.

I hope I could help you with my first experiences. Maybe yes synonymous jmd. Tips for me regarding the vibrations with the Biblades :-)

fovea   Aug 12, 2019 

awesome! thanks alot for that much informations and impressions! i beleive bloodylord flew on 4", probably higher rpm during the hole flight, this could make a difference for durability and heat - i guess.

IcarusIX   Aug 07, 2019  

the findings with the biblades is interesting considering success others have had with them, probably something funky going on with harmonics and the frame

Nightprowler   Aug 09, 2019 

I think I found the solution. Too much rpm. I'll test und tell.

fovea   Jul 28, 2019  

awsome - very nice! thanks alot for share, like to build the same or a near settup aswell. the hobbywing 1408 2400kv are in my focus for 4inch 6s settup, the druckbär frame aswell.
if you could share experience impressions in general or about props, motor heat on 4inch... would be very nice.
a dvr post would be pretty nice aswell, have a look how this performe.

BloodyLordV   Jul 29, 2019 

You should not be considering hw1408 for any kind of build. Those motors are horrible - the windings fall apart when you just watch them. I tried to use it - in 2 weaks I was able to destroy 6 motors... I have not tried Flywoo Nin 1408 2350 but they look like having a better secured windings so maybe those would be worth a try...

fovea   Jul 29, 2019 

thanks for your replay! what do you fly on your damon 4x legit at the moment?
i hoping for another example build from you :-)

Nightprowler   Jul 29, 2019 

Hello, I fly on the Druckbaer only 5 inches but from experience with my UL3 I prefer significantly triblades. I've had some problems with biblades in the past, especially regarding vibrations near full speed.
Regarding the engines, I hope you are not really as bad as described. When I ordered the Hobbywing, the NIN did not exist yet. But the NIN are so beautiful that it would probably be worth trading for that.
If I also have such problems with the windings, I will of course report this again.

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