Mikrokopter Newbie and a Cinestar 8.

F_777

New Member
I have recently been asked to fly a Cinestar 8 belonging to an established film company. I am familiar with the legal requirements (BNUC-S, Operations Manual, etc.) and come from a commercial aviation background plus I used to build and fly models in my youth so the actual flying and qualifications are not too daunting.

I initially spent some hours flying a Ladybird QR 4 to gain a little proficiency before starting flying the Cinestar 8. The chap who owns it (and the film company) assumed it would be quite easy to fly but did not get on too well with it, hence my involvement.

The machine has what appear to be mainly Mikrokopter components with GPS, a radio link to a USB interface for reading the various parameters and programming, a Graupner GR-16 receiver and MX-20 transmitter, 2 x Kypom 30C 4s2p 14.8V 10,000mAh and 1 x Buzzflyer 30C 8,000mAh batteries.

I have several problems which I am hoping someone reading this and with experience might be able to help me with. The unit seems to be relatively stable (I haven't ventured too much beyond hovering at realtively low level and gentle manouevres within 20 metres or so) but I rapidly hear beeping noises from the 'copter and the red tail boom LEDs flash and I assume this is low battery voltage warning but I am not sure. When I remove a battery after I get the warnings the voltage reading is around 3.8V per cell. I can see nowhere in all the settings to find out what level the low voltage warning is set at nor do I know what a sensible figure would be. I have also found that in the past few cold days here (around freezing point) that I can start the unit but the engines will not rev beyond a fast idle at about one fifth gas as if there is a fault but if I bring the unit indoors within a few minutes everything works normally. Is there some sort of low temperature restriction?

I have the Mikrokopter software but the only paperwork I have is a basic page and a half giving very rudimentary instructions on how to initialise, start the engines and stop them and a few tips but very little information otherwise. I also have a picture showing the switch positions for Altitude Hold, Free Flight, Position Hold and Return Home.

I have read a considerable amount on the Mikrokopter website and various other bits of information but confess that I am confused about a lot of what I read. I am obviously reluctant to start altering things I don't understand. The link at the bottom of the post leads to an album of screen shots showing what parameters are set and would be grateful if someone can tell me if they are roughly correct or if there are any glaring mistakes.

The MX-20 has V1.00 software and When I tried to set it up to receive telemetry from the Cinestar (I really would like battery voltage) I found that almost as soon as getting airborne I received a continuous beeping which didn't appear to relate to anything I could see on the MX-20 display, when I turned telemetry off it stopped!

I must sound like a complete numpty but I am not in the mood to press on regardless without fully understanding how the unit is operating and potentially having an accident because I have some serious set up issues.

I would be grateful for any advice people are able to offer.

[url=http://tinyurl.com/c7j46dx]Link to album here.[/url]
 
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ovdt

Member
The voltage warning means that, you're pulling more amps than the battery can supply, so it's draining the cells. It happens either the C rating is false; or the batteries finished their lifecycle.

If the Lipos are not puffy, than it means C rating on the batteries are wrong and you're pulling much power. If you check the amps consumed when hovering, you will get an idea.

The battery warning happens a lot especially flying 4S on heavy lift platforms.

So what can you do?

Simple.

Use 2 batteries in parallel so they will share the load. (You will double the C rating by using lipos in parallel).

If you still get some battery warning, it means two things: Batteries are rally bad. Or, motor/prop combination is wrong. Try decreasing the prop diameter or pitch. (Since I don't the specs of the kopter I'm just guessing.)

But I believe, you will solve this problem by using two lipos in parallel.
 

Himhoe

Member
I too have had the same thing happen with my CS8. My motors will start and not accelerate past much more than an idle in cold temps. I looked through the MK software for hours and couldn't find any temp setting. I now just let it warm up the motors and the BLs and then shutdown and immediately restart and take off.

I don't think that the batteries are the problem. I am running 30-35c 4s 6500s on my CS8 without any trouble. Reading on your issues of the low battery indication and what your batteries are reading after you land I'd say the low voltage warning is set around the 3.8v mark. You can change that in the MK software. It's on the Misc. tab, it's the 5th box down where it says undervoltage, enter the voltage without a decimal, (i.e. 3.5v = 35). I think I have mine set at 3.5 or 3.6v per cell which leaves around 20-25% left in my packs.

When I was starting out a few months ago I found somewhere a breakdown of what every setting in the MK software did. I'll see if I can't find that breakdown again and get you a link to it.

I hope this helps.
 
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Himhoe

Member
MK Parameter settings Summary

I found the setting breakdown and a summary of what each setting in the MKTool software does. It took me a while to find it.... send me an email and I'll send it to you. Or try this LINK
 

Himhoe

Member
i just found the photo album with all of your MK settings. I see you have the under voltage set to 14.8 which is too low it's set to the nominal 3.7v per cell. set it to 14v(140) or 3.5v(35) I've had good luck with this setting.

Does the Roll of the kopter feel like it's too twitchy or sensitive? Might try lowering the "Nick/Roll D" down to 4 to match the Nick/Roll P" That'll give you smoother flight. If you haven't yet I'd check the radio and put in some Expo to soften the feel around center stick.

Another thing that I was always forgetting to do was to "write" the new settings to the kopter. If you make several changes and forget to click the "write" button the changes won't take. I was trying to get the telemetry working on my Cs8 and it wasn't taking, I could fly but I had no telemetry data. I went back into the MKtool and selected my receiver again to make sure it was right and then hit "write" and suddenly my telemetry data showed up on my transmitter. I also am using the MX20 but with a GR24 rx.
 
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