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> Helicopters & Parts > Gyro & Stabilization > Tail Gyro


Hobby King 401B AVCS Digital Head Lock Gyro

Hobby King 401B AVCS Digital Head Lock Gyro

The now famous HK401B is known to have the same characteristics as the Futaba GY401. In fact we guarantee you wont know the difference!
No tail drift, excellent hold characteristics and a level of reliability only found in $100+ gyros.
Dont risk your heli with other cheap Gyros when the HK401B has been proven by thousands of pilots to be stable and accurate in a variety of temperatures and helicopters.
Compatible with both Digital and Analog systems
Minimizes rudder trim changes caused by wind, other meteorological changes, and varieties of helicopter attitude changes are automatically cancelled.
Sensor vibration proofing
Simple sensitivity adjustment
Digital proportional RIC system
Operating voltage: 4.8V ~6V( common for receiver)
Operating temperature: -lOL r-.rf-45 C
Dimensions: 28x26x20 mm
Operating current: 80mA

IMPORTANT: Make sure you isolate your Gyro from vibration. Use double sided foam tape and never use cable ties. Vibration will cause harm to the Gyro and degrade performance.
Manual found in the files section below.


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Weight: 27g
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Price  $11.99

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 Customer rated
Total of 546 discussions.
José Alfredo  1 points - 5/3/2015
How to plug the gyro, please. Four wire, two plugs ??
giuseppe  1 points - 4/26/2015
Riesce a supportare la lipo s2?
Zoltan  1 points - 4/9/2015
Hi, I just received my HK401B, but it doesn't work properly. When I connect the gyro to the receiver with the rudder input connector only and connect the servo, nothing happens... No indicator light, no servo movement. When I connect the rudder input connector and the sensitivity connector as well, then I get the steady red light, however, when I plug in the servo to the gyro, the red light goes off and again, no servo movement... Does anyone have any idea if the gyro is defect or I do something wrong...? Thanks in advance!
 Aefer 348 points
never heard of one doing this before.. have you tried the servo plugged into the receiver to see if it works as it should? You either have a faulty Gyro or Servo.
 Zoltan 1 points
Hi Aefer, thanks for your reply! Yes, I did plug in the servo directly to the receiver to see if it is defect, but it works fine., so servo is ok. I also did contact the customer support in the meantime, will try to sort out with them (they asked for a video which I'll record and give to them in oder they can see and hopefully detect the issue). What I'll also try tonight is to use a different receiver, probably the gyro and the receiver (Modelcraft 3CH 40 Mhz) don't like each other...
 Aefer 348 points
Ok then. Interesting that you say you are using a 3ch Rx, I assume you might be using it on a car/boat/bike? Because a while ago I tried to use one of these gyros on a plane and could not get it to function. it would only work on my heli with the gyro function active on my radio. I ended up using a rate gyro from an Esky heli. I no longer have any HK 401's so I cant experiment either dammit. Hope you can resolve your issue.
 Eduardo Buratto 5 points
Hello Aefer. What specifically happened when you try to plug this gyro on your plane? I want to get one for a 50cc Cap 232 but after reading your post, I have some doubts now. Thank in advance, Eduardo
 Aefer 348 points
Hi Eduardo, it was a few years ago that I tried it, but if I recall correctly, it did absolutely nothing, not even servo movement. It doesn't make sense to me. I might experiment with my radio and see if I can get some answers. It must be something to do with the signals it is receiving through the single yellow signal wire, but I can't be certain
 Aefer 348 points
Good news, I just came across a HK401 on my old HK 450. I was able to get it functioning on my airplane simply by plugging it into the rudder ch as usual, and setting an auxiliary channel for the yellow wire and changed the end points of the aux ch to set the gain. Zoltan, I hope this has helped your issue. Good luck Eduardo on trying one of these for your Cap. Happy Flying!
 Eduardo Buratto 5 points
Hi Aefer, thank you so much for your reply. Yes, good news indeed :) Especially controlling the gain with the single with aux channel. Im getting one piece ( maybe 3 - aile, rudder and elevator ). and I'll let you guys know as soon as I can. Btw Aefer, Top Gun next weekend? Cheers!
 Aefer 348 points
No worries, happy to help. Top Gun? lucky you, no such thing here in Oz, looks great though
folke190d  9 points - 4/7/2015
Matthew  2 points - 3/26/2015
hi can anyone help I have just got my hk401b gyro and I'm planing on putting on a 30 size heli can anyone tell me if that is ok or not Many Thanks
Nã*o é* um bom gyro.
 Aefer 348 points
It should do the job. My thoughts would be to minimize vibration as much as possible. ie, two layers of double-sided tape to mount it and balance rotors as best as possible. Ive used this gyro on electrics, I cant say well they handle nitro models
Customer Reviews
Review Blogs for this item
gyro used for Esky HB King 3
Fly less, spend more.
Overall Rating
143 thumbs up!
Ensure you do the fix for this gyro. This is a pretty decent gyro at this price... HK Rocks.

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Overall Rating
68 thumbs up!
IMPORTANT 2-minute fix for this gyro: ("" slash "hk401fix")

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Overall Rating
17 thumbs up!
The gyro is amazing. I used it in the road car model to manage and everything is in perfect order. I recommend this product for its sensitivity and price.

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13 thumbs up!
i figured for the price i couldnt resist trying one of these and i am not dissapointed this things works great just as good as my 401 futaba gyro you need to look at the mods section on this as i had to do that but the little time i spent doing the mod was more then made up for with the low price and great performance

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Overall Rating
12 thumbs up!
I bought this gyro to try out for HK 450 it does very well ,hold the tail is solid with JR servo DS290G, First I received, inside board was sloppy & I try on heli it doesn't work, then I Open in back gyro I sim double tape to hold them inplace worked very well fly good,good for $ too

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