HK-250GT Electric Helicopter Kit (Alloy/CF w/ Blades)
The HK-250GT is a high performance factory-upgraded heli kit. With it's true carbon fiber frame, hard alloy head and tail plus numerous upgrade components, the HK-250GT is sure to be a favourite amoungst micro 3D pilots.
Newly designed main rotor head set produced from billet alloy. Newly designed metal control lever and CCPM metal swashplate for improved 3D performance. New anti-rotation guide, with its strengthened frame base enhances the structural strength of the main frame. Single unit tail belt makes it easier to assemble and improving rudder efficiency.
Don't worry, arm yourself with knowledge! :-) Google for this: "t-rex 250 manual pdf", this is a manual that is very close to how the HK25GT is built. There is a document under the FILES section on this web page about build & setup, you get some hints about spare parts and setup there (it's for FBL, but most things are applicable for flybar too). Google for "trex 250 build video" to find videos that focus on building, problematic points to consider, tips and tricks etc. You can look on rcgroups dot com for HK250GT groups, and you can always get back here and ask specific questions. Good luck!
I use the XGD-11MB on swash, $4 bucks a piece, last two gears are metal and they are strong and precise. Fit perfectly into the HK250 frame too. When you say setup, what do you mean then, just the cyclic servos or the whole shebang?
OK, take a look under the FILES section above, there is a document called "HK250GT FBL build & setup". There you have a list of stuff, and some setup tips. It's for FBL, but most of the things are applicable for flybar as well. The FBL unit is replaced with a gyro for flybar, e.g. HK401B (don't forget to check if that gyro has a loose electronics board, look for "hot glue" on the HK401B product page). HTH
Anyone who ordered this recently and built it and flew it have any problems with their feathering shaft? I've looked on YouTube and saw a video of this model having a feathering shaft come apart during flight.
Have a look under the Files section here, the document named "HK250GT FBL build & setup". There is a list of material in it. It is for FBL setup, but most of the things apply to a flybar heli as well. If you don't want FBL then buy a gyro, e.g. HK401B. HTH
it depends on how much u wanna spend on the electronics.. for a cheap but nice setup u can use motor: L2508A-3500, Gyro: GA-250, ESC: HK-SS30A, Battery: N850.3S.25 and Servos: HKSCM9-6 or u can use HXT900 servos for ur swash.. thats what m using on my HK 250gt with a 6ch radio (with swash mix).. and do read the rewies .. they all work great for this little heli.. cheers!
The included pinion is 2.5mm. The DFC you mention fits, but it's a bit tricky to get the servo rods short enough and you might need some washers to adjust the up-down play in the main shaft since the DFC shaft has a fixed stop instead of an adjustable stop ring. Google in rcgroups for "250 DFC head" for more details. HTH
You mean about the existence of clones or the use of their manual? Good question, but I think these clones actually generate business for them, because not all HK parts are great, and if you want these helis to be as good as they can be, then you are going to need some A_lign parts in my opinion. The manuals are freely accessible as PDFs on the Internet, so I don't think there is any issue with those.
HK 250 screws are better than the align screws. HK 250 comes with metal and carbon fiber anti-rotation arm and front end of the belt drive, these parts are plastic on the trex 250. The Trex 250 is only better because of the tail case set. The tail pitch slider arm has a sub-arm that it's attached to, which often comes loose from the tail case. The Align tail case costs as much as the HK250 kit.
Main rotor, tail rotor and chassis come mounted, then you put it all together yourself. But don't trust any screw to be fastened with loctite from factory: Unscrew and check _all_ screws! Several crucial screws were loose or had too little loctite in my helis (have worked through a couple of these). No manual is included, so get the manual for the TREX 250, it is applicable on this one by and large. HTH
How many points do you have on your TX 3 or 5? I guess I would start with a linear curve 0 50 100 or 0 25 50 75 100 and adust from there, and set up the pitch as close to per Align Trex settings. which is probably something like 0 -2 degrees 100 11 degrees, and if you are to the point of autos and 3D you will set those differently. You should really never have to play with the throttle curves unless somthing is goofy, and you may need to dial in the pitch curve for perfect flight, but the 250 is pretty forgiving and should fly in normal flight with a standard linear curve.
Hi guys...I've built my HK250 with a Turnigy 9X. The motor is the Turnigy 2627 with the Turnigy Plush 25A ESC. At the moment, I have the swash all worked out but now I need help with the throttle and pitch settings. Thanks in advance.
I would say 3 or 5 points on the curves doesn't matter, the setup is similar. I do the cyclic setup of the heli with pitch curve 0 25 50 75 100. I setup so that full cyclic pitch at 100 cyclic input is 12 degrees pitch, then with 50% cyclic, right aileron is set to 8 degrees pitch. When this is done, I reduce the pitch curve for different flight modes to a level that I feel comfortable with (with 100% extremes, the heli really gets wild). I use pitch curves 48 49 50 65 80 for Normal, 20 35 50 65 80 for IdleUp1 and 0 25 50 75 100 for IdleUp2. The throttle curves I use are 0 25 50 65 80 for Normal, 90 80 75 80 90 for IdleUp1 and 100 95 90 95 100 for IdleUp2. HTH
Glad to help! A few warnings: make sure you don't go into IdleUp1 or IdleUp2 too soon, and (even more importantly) make sure you have good altitude when you decide try it (at least 20-30 meters above the ground). I didn't and I have actually crashed all my helis the first time I activated IdleUp2 (it makes the heli so much more agile and aggressive, and any mistakes are greatly amplified by the elevated performance, and the increase in head speed makes for a big jump in the air). But now I can do it and it's just fantastic what the helis can do! Take it easy and good luck!
Lassek, I used your settings and all is well except that during the spooling, the heli spins counter clock wise. I check the gyro and if I switch it to DR, it spins even faster.. counter clockwise. Any ideas?
I assume you have the rotors setup correctly, so that the main rotor spins clockwise when viewed from above, and the tail rotor spins so that the tail blades move against the ground at the rear end (I would double check this and also the tail rotor control arm setup against the manual first)? If this is the case, then it sounds like the gyro has the compensation inverted, so that it amplifies tail movement instead of cancelling it. If you imagine the tail rotor spinning the way it does when you spool up, and you move the tail to a side by hand (throttle hold or no blades mounted!), then the gyro must change the tail pitch so that the tail rotor blows air in a direction that _opposes_ the movement. This is very easy to get wrong (don't ask how I know... :-) HTH
Lassek, I do have Turnigy 401b gyro. I know what happens of the DR switch incorrectly set. It spins quite fast. My DR switch is correctly set but the heli still spins C/C wise. I can modestly counter act the spin by turning the joystick completely to the right but it still not enough.
OK, so the gyro compensates in the right direction? Then, have you setup the limit on the gyro to utilize as much of the available throw as possible without pushing against the extremes? When you move the tail left and right, the slider needs to move all the way it can on the tail shaft, else it will not have enough pitch. You might have to move the servo a bit on the boom to find the sweet spot where the gyro limit is set as high as possible, but the tail slider still does not touch at the extremes.
I haven't yet replaced the tail belt pulley cases on my HK 250's. Looking at the 250se manual, I don't beleive any parts at the front of the belt drive need replacing. I run an Align belt on one of my HK250's and it hasn't given me problems yet.
The front end of the belt drive is greatly inferior to the Align version in my opinion. The problem with it is that it sustains high forces when you crash which often damage the bearings in the front belt drive, so you have to exchange these bearings, but you can only get to one of them! And often the aluminium in the front belt drive bends, so you end up exchanging the whole piece (i.e. GT250-113). With the Align design the whole drive shaft is contained within plastics, no real chance of damage, so a lot more robust. But I'm still using the HK version, not sure that the Align parts fit and so far this hasn't annoyed me enough to do something. :-)
Don't get me wrong - it's a great helicopter, and you're getting a great deal on it compared to Align equivalent. You just need to get that 1 Align tail pulley case. Be careful where you put threadlock, because you need to take the main frame apart to replace the servos. Buy lots of landing skids as well. They are very tough but this helicopter weighs alot for its size, and they'll break in a less than perfect landing. I use 450 sport landing gear on one of my HK250's. If you find this helpful please like.
Replace the Metal Tail Belt Unit. The Align version is alot better than the Microheli and HK tail belt pulley case. I've went through 2 tail belt pulley cases because the tail pitch slider arm doesn't directly attach to the tail case, it screws into an extension arm which screws into the tail case, and it's only secured by 1 screw. The microheli tail case has this sub-arm secured by 2 screws, but it should be a part of the tail pulley case itself.
Agree Jake, have had the tail pitch slider arm loosen up and almost come off before I understood what was happening. Luckily the heli got more and more unstable in the tail only gradually, so I could land and went home to check it (fastened the arm again with more threadlock, but I just know it's going to come loose again). Its really a bad design, should be a single piece of metal as you say. Also, the aluminium in the central part is very soft, so you really cannot tighten the screws very hard either, and the screws are very short to make it even worse. :-) Change needed here, please HK! In the mean time, I guess hello Align!
Hi all, pls recommend me good tail servo for this heli, I had an ESKY-0508 and it burned off..
So now I have Corona DS919 and it's not good enough, because I have to decrease GA250 gain to 58% to allow me flying with 65% of throttle..
Thank you :)
Piro rate is really a settings issue (assuming your tail is mechanically correct, pitch slider has full travel with no binding). check the dual rates and expo on your tx make sure dual rate is at 100% and maybe 20% expo to start with so the rudder stick is not to touchy while testing flight. also your endings on your tx is * 100%. and double check your gyro settings. what gyro and transmitter are you using? maybe I can help you farther. but start with this and do a test flight.
While they are not exactly like an Align Trex, and there are a number of different Trex 250s, the Copter X instructions, which I believe you can down load are more exact to the HK 250 GT. There are some subtle differences to the Trex 250s
HKSCM9-6 or HXT900 for cyclics , Turnigy plush 25A ESC ,Turnigy 2627 Brushless Outrunner 3800kv. (You will need to sand/dremel a few mm off the shaft to stop it from hitting the servos , Pinion: 2.3mm/0.4M 13T , for gyro you can try hk401B or turnigy 302 with D922MG Digital Metal Gear Servo , battery ZIPPY Flightmax 800mAh 3S1P 20C , charger turnigy 2-3s charger(nice charger)
I saw the HK 250 Kit a couple of days ago, but now it seems to be gone from Hobbyking, and only the HK 250-GT is left here. I was wondering if anyone knew if it had been taken off completely or what, and if you were to recommend me if i should buy this kit compared to the plastic one if it is still available?
This kit could be considered as a full part replacement set for your T-Rex 250. It is the most cost effective way to recover from a crash the same day having all spare parts in stock :-)
Tried some parts on my T_Rex and they worked flawlessly, you can never go wrong buying from HK.
How about making an FBL/DFC version of your 250 heli ?
Nowadays FBL is "the way to be" so it would be nice to have a genuine HK-250 FBL/DFC without having to modify them afterward, which cost almost the same, if not more, than the complete kit.
You need to open a support case with HK if you really want to be heard in matters like this I think. I have done it a couple of times and I do get the feeling HK is taking in what you say then. FBL conversion is not crazy expensive, the FBL head that I used is just under 20 bucks. The most expensive part is the FBL unit, I used the ZYX-S to avoid a separate RX to save weight (used one sat directly connected to the ZYX-S, works like a charm). I agree with you David, why hassle with FB paddles when FBL is so much easier to work with (and less things to fix when you crash :-). I would like a nice cheap FBL version of the HK600GT (both belt and TT versions to allow choosing between crash resilience or transmission efficiency), and why not an integration of the full-range OrangeRX R710 with the ZYX (with sat ports), without making the plastic box bottom wavy, thank you HK!
Thank you for your info. however There's no tail motor.. it's driven by a thin long round shaftwith gears and that is all that's broken...the unit came that way years ago, and it was never flown, i cannot find replacement part. Just getting into building hobby and thought that it might be interesting to learn to build with parts i already have..any ideas as to what kit might work with what I have. it's 4 ch, gyro with 3 in 1 receiver, 370 carbon brush motor tail driven by transmission gear system.again just learning so want start with little investment...Thank you for your time
So the 22D is fixed pitch with one elevator servo, one roll servo and one servo for the tail pitch, is that correct? You only have one fixed pitch heli here as far as I know, this one: NE30232824102, but it's RTF. I guess you could try to convert a CCPM to fixed pitch and only use two servos for cyclic control. As most helis here are CCPM and you need 6 channels for that (and probably stronger servos and motor), I have a hard time seeing a combination that will make you happy both money-wise and fly-wise. But check this one out just in case:FX-200-KIT. Perhaps you can convert it to fixed-pitch and use your stuff, and it's certainly cheap (but buy two so you have some spares). Or how about an airplane instead of a heli? AXN Floater Jet is a real blast to fly, cheap in ARF version, and it's very kind to beginners (i.e. it can take quite a lot of crashing without breaking too much). HTH
Hello I have a old Walkera 22D with a 370 carbon brush motor and the servos, receiver w gyro and the transmitter the tail rotor gear is stripped I was wondering if the HK 250 GT would be compatible unit with the parts I have ....Anyone know???
The 22D servos are only 0.9kg in torque, which is around half of what is recommended for a 250 size heli, so prepare to exchange them fairly quickly. The 22D is a 4-channel as far as I know, so it's not really possible to use the radio with a CCPM heli like this 250. The motor is another issue, it's uncertain if it fits size-wise or motor-mount -wise. The motor pinion might need to be changed, is that possible and can you find one that fits? It's also less efficient than a brushless with more maintenance to do. And the 22D has a tail motor, right? So you need to replace that with a servo, and where would you plug that servo into the 22D 4-in-1 unit, is there even a tail servo output on it? If not, then you need an ordinary RX and gyro and ESC to replace it. Seems to me the outcome is most uncertain, not likely to make you happy but likely to have you exchange one part after the other. I would ditch the 22D and buy a HK450TT FBL instead (cheap spare parts and a lot more stable in the air than this 250). HTH
On a side note though, the pinion will need to be drilled out to 3mm to fit. The motor has a stepped shaft, as you probably know. Just mount the drilled out pinion with the set screw closest to the motor so it screws agains the 3mm part of the motor shaft.
Yep all is well. I received the kit on monday and maiden flew it this weekend. I'm quite impressed with the quality of this kit. To make the 3900 motor that comes in the B L A D E SR kit work with the motor plate i had to file out the holes a little bit and as you said drill out the pinion to 3mm for the stepped motor shaft. The servos from the SR just dropped in and even the gyro worked. A drastic improvement from the original heli. The Piro rate is a little slow but its much better than the uncontrollable nature of the SR and that God awful tail wag.
Amazing value for money despite a couple of first batch bugs. Mine came with the wrong bearings in the grips too, I replaced with Align ones and also added two bearings on the seesaw. The bushes that I removed went to make chinese weights on the tail blade bolts. The tail needs a little CA on the ball joint to fatten it up and also a dribble on the thread of the screw going through the tail slider control arm bush. Those mods fix the tail wag and remove the slop in the tail. I can now dial 55pcnt (Futaba) gain and not wag like a demented puppy.
Blades were not much to write home about but no surprise, Align carbons work well.
Hey Hobby City...some CF blades next please )
All in all a nice little heli, flys great after some simple mods.
7 comments. Reply..
32 thumbs up!
5 stars.......this heli is perfect,i am a 3d pro and bought this little heli to fly indoors on a tuesday...exactly the same as the trex se and handles 3d just as good.... my set up
turnigy 2627 Brushless outrunner 800mah 3c lipo turnigy 25a plush esc telebee gyro.......futaba s9257 tail servo with Z kink in the push rod.... Hextronik MG-14 Metal gear servo....a little long but wow what a good servo and good centering...
Landing skid is a bit on the soft side, but no worries.
Towerpro 9g servo is a tight fit in the CF frame.
Head will need to be thread locked for security and all other screws should be checked before flight
As always no manual but Trex manual can be downloaded
Tools and spares are included as well a 15t mod 0.4 pinion
CNC parts finish is good
4 comments. Reply..
22 thumbs up!
Metal aksam canopy ve carbon gvde ok gzel grnyor. Canopi takldktan sonra alt ksmda boluk kald. Delinecek yeri iyi ayarlamak gerkiyor. Servolarn taklaca yuvalarn kenarlar dzgn deil. HTX900 servolar tam oturmad. Servo yuvalarn 1-2 mm enine geniletmek gerekiyor. Gelen Tail Support Rod lardan biri 2mm daha uzundu, uratrd. motor vida aral 19 mm. kutuda gelen 15 pinion gear 2.5 mm shaft icin yaplm.
Good copy of the T-Rex 250. Special attention should be observed in the assembly, with regard to the essential use of Thread lock. If the person does not use Thread Lock on the screws that uprendem metal parts, runs the risk of letting go some part in flight. I've been through this problem. Another special attention should be given the choice of motor and pinion, so as not to create a Great Headspeed, which would cause the explosion of the blades, and destruction of the helicopter can still hurt someone. I think a maximum around 3800 RPM the blades would be in leading a good margin of security risk for this model. A simple way to obtain the value of Head Speed of your system:
No Kv motor x No Teeth Pinion x Battery voltage / number of teeth on Main Gear = maximum Headspeed Helicopter using 100pcnt power.