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Old Apr 22, 2015, 05:01 PM
6 Channel Noob is offline
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Sonuva.......

Sorry need to vent, question is at the bottom.

Since before christmas I have been putting the pieces together to build a 450 size MD 530. I bought a scale fuselage kit and 5 blade rotor head from a local guy off craigslist. I bought a Gartt 450L and their supercombo kit which came with the blue mini Kbar. I got a devo 7 channel RX so I could just use my devo7 TX. Then I decided I wanted to upgrade the servos so I bought 3 more KST 215's and a 515 servo and a bigger 1800 kv motor and 45 amp ESC to go with a 22v 6s lipo battery pack. All this over about 6 months.

Since I don't really know what I'm doing I was trying to figure out how a 5 volt ESC was supposed to power 7.4 volt servos. I figured I would have to get yet a third ESC. Of course then I was wondering how a 7.4 volt BEC powers the gyro and reciever without frying it. In trying to figure out what voltage the mini kbar and reciver would accept I had to look on the VBAR site for documentation and hope that they would work for the clone kbar as well.

Right there in the add it says the following:

Do not use the Mini V-Bar in the following types of helicopters:
- Scale helicopters
- Helicopters with multi-bladed rotorheads (3+ blades)
- Custom built helicopters.



It handles ~3-~9 volts, but not on a custom built 5 bladed scale heli.

Anyone know why you should not use this in this type of heli? (Aside from it being a clone?)
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Old Apr 24, 2015, 10:48 AM
sp00fman is offline
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Sounds they are covering themselves against liability for mishaps.
Best look up a scale/multiblade forum to see what gyro they use. I suspect the "v"-bar is fine but start with low gain settings. Best not risk your heli and search around a little.
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Old Apr 24, 2015, 11:28 AM
Florida Heli is offline
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There is no substantial difference between a KBAR and a VBAR. The differences are minor mechanical ones internally. The KBAR use different gyro chips. They perform the same.

I am currently building two 450 scale helis. Both will be flying on mini KBAR. Just because a heli is scale does not mean that it's somehow different from any other heli ... unless it is modified. A lot of scale flyers lower head speed substantially. This can affect the feedback loops in the FBL controller since they are designed to work in a certain speed range. Some scale builders don't even use a FBL controller. Multi-blade heads fly different due to the loading on the rotor. They run at lower head speeds. More info can be found in the scale forum. I'd head over there for more detailed answers. There also is a lot of info in the FUBAR thread, and I would post there as well.

-Florida Heli-
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Old Apr 25, 2015, 11:40 PM
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Quote:
Originally Posted by Florida Heli View Post
There is no substantial difference between a KBAR and a VBAR. The differences are minor mechanical ones internally. The KBAR use different gyro chips. They perform the same.
No they don't all perform the same.

I have the blue Kbar the Fly Wizard GV8000 and the full size yellow Kbar. The GV8000 is an exact clone that uses three Invensense ISZ-500 gyro chips like the real Vbar and it is more locked in than the Kbars. The blue Kbar is almost as good, but not quite. It uses a two axis ITG-650 for cyclic and an ITG-500 for the tail but strangely the tail still doesn't seem as locked in as with the GV8000.

The yellow Kbar (mini and full size) use a single Invensense MPU-3050 three axis gyro chip. The tail on these units requires a lot more tweaking and the units seems more susceptible to vibration where with the blue unit and GV8000 it's basically just set it and forget it.

Also the board work on the GV8000 is much better than on the blue Kbar. The yellows have good soldering but still not as good as the GV8000.
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Old May 05, 2015, 10:20 PM
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Strange, on the German site there's no such warning and the manual even mentions scale helis.
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