The HK 500 Thread

[Crazy L]

Hi guys

I know that, although there is some info on this clone on another forum, there isn't much on here, despite people asking about them. So I thought, despite my limited experience in flying and building, I would share my experiences in building and maintaining. If anyone wishes to chip in with something I've missed, or not got to yet, or has a better idea, please do so. As a quick note, I know a lot of people will probably say: "just buy a trex", but the thing is, I built mine as an exercise to see if I could build one on a budget as I currently don't have a great deal of disposable income, plus I'm still learning basic maneuvers in the air.

I bought the HK 500 and opted for the cmt as it came with all the ali bits, I figured that chinese ali is likely to hold up a bit better than chinese plastic. Considering the difference in cost, I thought that a no-brainer too.
I also went for the belt drive version as, as a beginner, it would be more forgiving if it took a clout.

Landing struts: Now, I had heard that these were rather brittle. There is a method that sometimes works for this. I come from the RC car world and very often, a kit will be cursed with brittle parts, this is usually solved by boiling. As this costs nothing to do, I gave it a go. Alas, during it's 3rd hover when the cells died quickly and a hard landing, one of them snapped. Trex part fitted.

Gyro: I had a spare Assan Ga250, that was given to me by a kind person on the other forum, in fact he gave me two. One went in the 3D Storm to replace the pooey HL400, and the other went in the 500, just to see if it would work really.
It does, I can only do simple stuff bu the Assan holds the 500 solid. £10 for one of these mini mems gyro, bargain.

Cells: Turnigy 3000mah 6s. Simple, cheap, and as with the other turnigy cells I've had, reliable.

Electrics: Once again, due to price, I turned to Turnigy for the motor and speedo. I opted for, upon recommendation, The helidrive SK3 1600kv motor and 85a ESC, this came to roughly £50. Servowise, I found 3 Align 510s for cyclic and a 520 for the tail all from the same seller, new without packaging with all hardware, and this came to £70, again, bargain. The servos came with ali arms, but I did not use these as the link rods were not straight no matter what hole I chose. Plastic ones were chosen, this could be an advantage for a beginner as they could be sacrificial in the even of an "incident". I'd rather hunt about for another servo horn than another servo.

That's the build anyway, next up comes my tips after getting the thing flying.

[Crazy L]

I found the plastic ball joints on the head a bit loose, and inconsistent. So trex ones were bought, but to be honest, I've not fitted them yet, a dozen and a half flights in with no failings.....yet. The anti rotation screw sticks out too far and as a result, there is only a couple of mm of thread in the swash plate. I dremeled about 1.2mm off the end of the ball sleeve, so it was more secure on the swash plate. This cost nowt.

I found that the 3000mah pack did not allow an easy fit of the canopy. Hmmm, I lowered the cell tray by about 8mm. This was done by drilling new holes lower down, matching the cell tray, and dremeling off the excess material, but then giving it a rub down so both halves are level, and not crap looking. Result, canopy fits great, and cost nothing to sort.

I had the tail bearings collapse on me last week. I could not remove the bearing shells as the tolerance in the ali tail plates are of an interference fit, so I bought a new tail unit from HK, $7.60, hardly breaking the bank. I dismantled the new unit and removed the bearings, which had be beaten out due to tight fit. I used a wire cone tool in my dremel to remove the anodising from the bottom of the bore and a small sanding drum in a cordless drill with 1000 grit wet n dry wrapped round the end, with a bit of spray lubricant to clean the rest of the bore out. The bearings then pushed nicely in, so this bit of preventative maintenance will mean I wont need to buy another tail unit in the event of another bearing failure.

Trex belts are a touch shorter than the HK belts. My heli met the washing line and snapped the tail belt (amongst other stuff as it fell out the sky) so I installed trex, for this I found the end of the boom needed about 2mm of material to be removed.

That's it for now. If I come across something I've missed, I'll put it up, likewise, if any of you sages have any nuggets to share, please do.

[helijohn]

I found the plastic ball joints on the head a bit loose, The anti rotation screw sticks out too far and as a result, there is only a couple of mm of thread in the swash plate.

Do you have any pics of the result after Dremeling it?.

You must have built this at about the same time as me. Did you teardown the head. I found with the links removed that on blade grip felt very rough and had read that there was a lack of grease in the thrust bearings so I went in. I too found there was no grease at all but worse there was glue over the bearing's race. It is no wonder the grip felt rough. At first I thought it was a damaged race. Only when I began picking away did I realise it was rock solid glue. Arghhhhhhhhhhh.

[stinker]

Good read this Gents, I have been building my HK500TT CMT (gift from a while ago) as and when I have had time. To be fair, my kit anyway, the quality has been ok so far. Just need some reliable servo's (when funds permit) and we'll see how we go from there.
Kep us posted with how you are getting on Crazy L! :-)

[helijohn]

Good read this Gents, I have been building my HK500TT CMT (gift from a while ago) as and when I have had time. To be fair, my kit anyway, the quality has been ok so far. Just need some reliable servo's (when funds permit) and we'll see how we go from there.
Kep us posted with how you are getting on Crazy L! :-)

I'm interested in how you get on with the torque tube tail as opposed to the belt.

[Crazy L]

You must have built this at about the same time as me. Did you teardown the head. I found with the links removed that on blade grip felt very rough and had read that there was a lack of grease in the thrust bearings so I went in. I too found there was no grease at all but worse there was glue over the bearing's race. It is no wonder the grip felt rough. At first I thought it was a damaged race. Only when I began picking away did I realise it was rock solid glue. Arghhhhhhhhhhh.

I stripped the head down yes, and found bone dry thrust bearings, I expected this though to be honest, as when building rc cars with ball diffs, it is par for the course to strip and re-lube if it comes pre-assembled.

Re: anti-rotation screw ball sleeve thing. Just to try and make my self clear, the rear swash linkage, that is held in place via the tall slotted bracket. the ball at the swash is part of a longer item, a sleeve if you like, the screw is too short to provide a decent amount of thread, general engineering rule of thumb say you want 1.5d for a good thread depth (1.5 x diameter of thread, eg: M2 x 1.5 = 3mm of thread depth) I simply dremeled about a mm off the end of the sleeve.

Regarding glue, soak the parts in acetone, this will remove any glue without harming even the chinese ali. (we use acetone vapours to remove tyres from rc car wheels)

[Crazy L]

Had an issue today as I went out for the 1st time in a couple of weeks, well, since the whole tail thing really. My heli now emits a noise that doe's not induce confidence. I can't tell just yet what is making the noise, but I have checked belt tension and movement of parts, and all seems fine.

My other issue is that after about 30 secs of hovering, the gyro/tail lets go and the thing begins to rotate anti-clockwise/left, this is not meant to happen, and hasn't happened before. Hmm, the plot thickens.

[Crazy L]

Oh yeah, glad you're liking the thread btw. I don't have a lot of time to spend on the heli, so it's more of a as and when kind of thing, but I like to share my goings on with you incase there's someone else in the same boat. We all have to start somewhere right.

[helijohn]

Regarding glue, soak the parts in acetone, this will remove any glue without harming even the chinese ali. (we use acetone vapours to remove tyres from rc car wheels)

I used to ( and still do) use nail polish remover, the sort that has acetone but lately have found isopropyl is the business.

When I looked at the thrust race first I though the ball bearings had indented the groove probably through over tightening. I started running my nail over the indents wondering if I could smooth them away with a tool and not have to buy replacements and to my amazement it started to come off so I just picked away at it.

I guess pre assembly is not to be confused with ARTF and RTF kits.

[helijohn]

Had an issue today as I went out for the 1st time in a couple of weeks, well, since the whole tail thing really. My heli now emits a noise that doe's not induce confidence. I can't tell just yet what is making the noise, but I have checked belt tension and movement of parts, and all seems fine.

My other issue is that after about 30 secs of hovering, the gyro/tail lets go and the thing begins to rotate anti-clockwise/left, this is not meant to happen, and hasn't happened before. Hmm, the plot thickens.

So there is no tooth damage at the tail drive gear assembly? What is the mesh like with that and the auto gear? Is the auto gear flat?? What you are describing is what I had and was looking at when the tailcase started to twist round on the end of the boom. I was five hours finding a way to stop that happening. I was using a mems gyro and I took that off. When a heli lets go I always fall out with the gyro or the tail servo. Todays trial run on the test bed then on the grass seems not to have that problem any more.

[Crazy L]

So there is no tooth damage at the tail drive gear assembly?

No chief, I'm running belt drive. but as for pulleys, they're fine too. I will investigate more when I have time. Will fire it up on the floor and just wait to see if tail lets go all of a sudden. When I went back to the car yesterday, the blue light on the gyro was flashing (forgot to mention that bit), it should stay solid.

On a side note, I mentioned a weird noise that I couldn't track down. Whilst sat in the lounge looking over the heli (packing stuff as we're moving, just had to swap lawyers as ones we had did nothing for a month and a half, long story, don't get me started) I noticed a chip on the leading edge of a main blade, this wasn't there when I balanced them the other week, now when I bolted them on to the heli. I'm wondering if that could be the noise, as it has lightly splayed the edge of the blade, leaving an interrupted surface on the leading edge.

[helijohn]

No chief, I'm running belt drive. but as for pulleys, they're fine too. I will investigate more when I have time. Will fire it up on the floor and just wait to see if tail lets go all of a sudden. When I went back to the car yesterday, the blue light on the gyro was flashing (forgot to mention that bit), it should stay solid.

On a side note, I mentioned a weird noise that I couldn't track down. Whilst sat in the lounge looking over the heli (packing stuff as we're moving, just had to swap lawyers as ones we had did nothing for a month and a half, long story, don't get me started) I noticed a chip on the leading edge of a main blade, this wasn't there when I balanced them the other week, now when I bolted them on to the heli. I'm wondering if that could be the noise, as it has lightly splayed the edge of the blade, leaving an interrupted surface on the leading edge.

What is the gyro did you say?

I found the mini mems to be a pain.

I was thinking a broken off tooth could cause the problem.

A splayed blade would surely give a whistling type of noise I would have thought.

[stinker]

Sorry for late reply Gents, so far no bother with torque tube, as the drive shaft was bent upon delivery! Swapped for align, no probs since! I will see how it holds up once I get it airbourne properly. I have high hopes that it will do for my beater until my skills improve.

Cheers!

[Crazy L]

Funny you should say that Stinker as when I was reading up on the hk before I bought mine, a number of people were saying they had bent torque drives new in box, thats another reason I went for the belt.

Helijohn, I'm using an Assan ga250 vyro, mini mems. I have the same in my 3D Storm, and its been good so far. All the teeth on the main gears are fine. It's cheating i know but I may fill the blade then dress it out, just to see if the noise clears off.

[Crazy L]

Ok, so i've filled the chip on the blade with "magic", an epoxy we use at work, balanced them up again. I never thought to mention this but the tail let go at the same time a boom support became unscrewed at one end. I'm wondering if the extra vibes were too much for the gyro and that's why it wasn't holding. So I used machine screws instead and threadlocked them in, weren't before as they were self tappers and I didn't think they would come out.

I spooled it up in the kitchen minus main blades so it was still on floor when gyro let go, it didn't.

Proof is in the flying I suppose.