Turn SR into HK250SR ( W/ Pics)

[Excalibur3]

So how is everyone's HKSR's making out?


HK250SR,Blade 450 3D,Blade 450 X,DX6I, Phoenix V4, Blade Nano CPX

[Andre LaFramboise]

Still in the box but plan on getting it done when i get back from florida next month.then i have a trex 250 dfc to do after that.

[crashycanuck]

ordered my kit including the hkscm9-6 singlechip digital micro servo for the tail and a 2.3 mm 13 teeth pinion. alsoma spare set of blades for less than $6.

i cant wait to get the kit! my order hasnt shipped yet but it's "been printed and being packed in the warehouse"

[rwestbrookjr]

I'm in the process of moving. Will be mid December before I can order parts and get it back in the air. For now the Nano and SIM are keeping my thumbs warm.

Using tapatalk, the typos are not alcohol induced.

[skifreestyle]

Just built mine from the info this thread! Cheap hk pinion set screw crumbled on install and I'm waiting on a new one in the mail from hk to get her in the air and try her out. The heli is quite a bit smaller than I expected compared to the sr.

[cjmcca14]

Originally Posted by SYMAWD

Ok guys, it is now in the bible sticky.

So cool! Gret job

[1150GS]

Originally Posted by Excalibur3

So how is everyone's HKSR's making out?


HK250SR,Blade 450 3D,Blade 450 X,DX6I, Phoenix V4, Blade Nano CPX

I am one happy camper so far. Again I would like to offer my Thank You to Exaliber for this fantastic conversion idea.

The machine has 257 packs through it. The only failure of a stock part is the lower bearing of the tail drive shaft. I've replaced other parts from having a low experience level and being subject to laws such as gravity. I am about due to replace many bearings due to wear. I'm new to helicopters so I don't know if this is a low or normal life time for the bearings. And I have absolutely no idea if going to a high price bearing will gain me anything more.

Edit to add that I did have one of the tail blade screws fail one day a while back. It threw the blade of course, but it was able to auto in while in throttle hold.

I ordered my first kit from the USA warehouse and then two more from the Orient. I am impressed by the improvement in the level of quality over the first one. It appears that HK just might be watching and listening to their customers.

The first tail drive/hub unit was very fiddly to get proper operation, The second worked as it should out of the box. The third one I have also appears to be acceptable out of the box. All of the parts I have in the second batch seem to have an improved level of fit and function. Also the stock SR tail gyro was not up to the task of keeping the HK250SR tail in control.

My HK250SR runs with less vibration than the SR did, but it took some work to get there.

The HK conversion requires time, work and some ability to make it function well, but I think in the end it is well worth while.

[metalwizard]

Originally Posted by Excalibur3

So how is everyone's HKSR's making out?


HK250SR,Blade 450 3D,Blade 450 X,DX6I, Phoenix V4, Blade Nano CPX

I LOVE mine. and I NEVER loved the sr stock.

IT flies NICE. very stable very quite and LOTS of power.

Looksreally cool (got a fusuno canopy on it and the two piece align landing gear)

also it feel like a heli should not like a toy..

thanks for the insight best $35.00 I have spent on the sr since day one!!

[mechanicatwork]

Maybe you guys should start a "Post pictures of your HK250GT-SR" thread. Would love to see some of these birds as I have thought about this conversion as well. Is the main frame the same as the Align 250? or if that is damaged do you have to buy another kit? That and I have seen colored and carbon fiber versions for the Align and wondered if they would work on this conversion.

[rwestbrookjr]

Originally Posted by mechanicatwork

Maybe you guys should start a "Post pictures of your HK250GT-SR" thread. Would love to see some of these birds as I have thought about this conversion as well. Is the main frame the same as the Align 250? or if that is damaged do you have to buy another kit? That and I have seen colored and carbon fiber versions for the Align and wondered if they would work on this conversion.

The main frame is similar but not exactly the same. I know for a fact that on the HK kit, the bottom plate and landing struts are one unit wile on the Align kit, they are 3 separate pieces. Also the latest release of the TREX250 has the tail servo mounted in the frame and not on the boom so I'm sure this will change the configuration of the main side plates. As best I can tell, the boom is still the same length between the two. So the short answer to the last part of your post is most likely not. The HK kit does have CF frame pieces with aluminum bearing blocks, but I don't believe it will be directly interchangeable with the latest Align ones.

[DKS_ONE]

It may be that Align is doing a bunch of design changes to keep the clones from being so easily acquired and then stepped up with their parts rather than being able to sell a full on kit? The tail servo location has changed on the 500 and 600 as well as far as I know. And there has been an implementation of helical cut main gears and pinions on 500, 600 and (I think) 700. So on the latest kits, no, some parts compatibility will be an issue. But you should be able to find the previous generation parts widely available I should think and perhaps those frames would be a match? Might be worth a look to see if there are 2 listings for the parts, one for previous gen and one for latest gen. Just thinking out loud

[Xpcgamer]

Well I have the kit put together. All servos are in just need to set up the throws,End links, Set up the ESC,Gyro and everthing else!. I put an old Align body on it so now none of my SR or 300X batteries fit! I need new batteries now. Anybody wanna share a base line link length? My HK kit did not have any instructions in it.

[metalwizard]

Originally Posted by Xpcgamer

Well I have the kit put together. All servos are in just need to set up the throws,End links, Set up the ESC,Gyro and everthing else!. I put an old Align body on it so now none of my SR or 300X batteries fit! I need new batteries now. Anybody wanna share a base line link length? My HK kit did not have any instructions in it.

I redrilled the mounting holes on my canopy so they were right at the end of the tabs. my stock sr batteries fit.. a little tight but they do work.

for setup. I did not do anyhting with measurements. but at midstick (both sticks) set everything level. it will fly just fine. (unless you really want to go through a full setup)

I found at zero and level it took a little more left stick to get lift so I added two turns to the bottom links, and BAM liftoff and hover almost exactly midstick.

[Air Wolf]

Well the HK 250 is done now. It took a while mostly due to messing up the pinion gear while drilling it out. Had to wait for a new one from China. Bought a whole extra kit with it due to the shipping cost from the US or China being almost half the cost of the whole model. Anyway all is well now. I did have to reverse the motor direction from the SR. The HK rotor was turning counter clockwise, I have leveled the squash plate at mid stick and checked the pitch; it is max at 12 deg plus and minus and follows the pitch/throttle curves as best I can measure it. Will try and fly it tomorrow if the rain stops. I will post a note and let you guys know how it does.
Again a thank you to Danno and the rest of the bunch that helped me through the build.

[DKS_ONE]

Originally Posted by Air Wolf

Well the HK 250 is done now. It took a while mostly due to messing up the pinion gear while drilling it out. Had to wait for a new one from China. Bought a whole extra kit with it due to the shipping cost from the US or China being almost half the cost of the whole model. Anyway all is well now. I did have to reverse the motor direction from the SR. The HK rotor was turning counter clockwise, I have leveled the squash plate at mid stick and checked the pitch; it is max at 12 deg plus and minus and follows the pitch/throttle curves as best I can measure it. Will try and fly it tomorrow if the rain stops. I will post a note and let you guys know how it does.
Again a thank you to Danno and the rest of the bunch that helped me through the build.

Cool! And you do have your pitch going the right direction right? Last I read in another thread you had swash going down with positive collective which I think would be backwards to what it should be. Would be correct on the SR but not on this 250 I do believe.

[Air Wolf]

Hey Danno, Thanks for the reply and yes it still goes down for positive pitch.
I can change to go up by changing the settings for the squash plate mix and maybe reversing some of the servos. Is this the best way? Would this mean the clockwise blade rotation would be wrong? It rotated counter clockwise when I first set it up with the ESC leads hooked up color for color. Which is the correct rotation? The manuel does not say, or at least I couldn't find it, which way it should rotate. The drawings in the manual show the blade leading edges set for clockwise rotation.

[rwestbrookjr]

Originally Posted by Air Wolf

Hey Danno, Thanks for the reply and yes it still goes down for positive pitch.
I can change to go up by changing the settings for the squash plate mix and maybe reversing some of the servos. Is this the best way? Would this mean the clockwise blade rotation would be wrong? It rotated counter clockwise when I first set it up with the ESC leads hooked up color for color. Which is the correct rotation? The manuel does not say, or at least I couldn't find it, which way it should rotate. The drawings in the manual show the blade leading edges set for clockwise rotation.

Yes it is a clockwise rotation and it is trailing edge control as I recall (mine is currently packed) so when your swash moves up, it pushes up on the washout pulling down on the blade grip thus creating positive pitch. If yours is operating opposite of this I would suspect that your blade grips are flipped over.

[DKS_ONE]

Ya, grips flipped would do it... but simply changing the pitch mix in the swash mix menu would change the direction. So if it's -40, change it to +40 or vice versa This should not affect the rotation of the blades at all, just pitch... That said, if your swash goes down are you actually getting positive pitch??? That's the question, all this is a moot point if you get positive pitch when you move stick positive regardless of how things are moving hahaha!

[Air Wolf]

Danno,
That is what confused me after your first post. I do get positive pitch when the squash plate goes down. The leading edge of the blade rotates up, I think that is positive pitch. If you think this is right should I leave it as is?
The head came assembled with the kit but that doesn't mean it was put together right at the factory. How would I check to see if they are flipped?

[DKS_ONE]

Originally Posted by Air Wolf

Danno,
That is what confused me after your first post. I do get positive pitch when the squash plate goes down. The leading edge of the blade rotates up, I think that is positive pitch. If you think this is right should I leave it as is?
The head came assembled with the kit but that doesn't mean it was put together right at the factory. How would I check to see if they are flipped?

Ok, first and foremost if the head was assembled, it doesn't mean it's assembled right and 99% (more likely 100% but I'll say 99) likely no loctite was used in assembly. Usually parts are assembled prior to shipment to check for fitment and QC. So, I would certainly be taking the head apart, cleaning up all parts and thread locking all metal to metal contact screws.
Next, I'm darn sure Align helis are all trailing edge control, so I can only assume the same for clones. If the grips are on the right way, USUALLY, not always but usually, there is a logo on the grip and it should be facing up (IE: HK250GT would be printed on the flat of the grips). If they are facing up, you likely have them on the right way. If it's trailing edge control, that means the ball that the control link snaps onto will be on the side of the grip that the trailing edge of the blade is on. Hence, it's controlled from the trailing edge side.
In the end, if the leading edge of the blade rotates up when your collective stick is moved up, then you are indeed getting positive pitch with increased collective. The question at that point would be is the geometry right? So, with that, I would suggest perhaps tossing a couple pics up of your head build just so we all could have a gander, then we can be sure

PS - Sorry for late response, WAS at work when I left last message, now at home after some errands.