HK 500 GT

[Bravedan 106]

I have taken the plunge and ordered one of these from Giant Cod. Adverse comments around on t'internet relating to this model all seem to be old ones which relate mostly to extreme 3D use and the common areas of "concern" seem to have been all addressed in mods to build standard on current issue. We'll see!!!

 

Part of the reason for going to a bigger EP Heli is my travelling gets me near my club sites and with flying time, but transporting starters and fuel is an issue in a car often already loaded up with tools, and while my 450's (inc a HK 450) are great little machines, they ultimately are not that wind worthy.

 

This bird uses 6S cell size, that is, using my supreme maffematikal powers, it can use two times 3S...........

 

SO, my 3S 2300 450 size batteries can be used in matching pairs.

 

With the base Heli kit under £60, initially at least a £10 gyro, etc, will it be cheap and cheerful, or cheap and rubbish..............

 

Watch this space.................it might save you some money either way!!!

[Bravedan 106]

Blimey, was that last post here April......................

 

OK, so it's built. The frame build was painless once started, it all fitted and no cheese screws were discovered.

 

Gear installation was made a little more awkward as the perfectly fitting Turnigy servos were not available, and Align ones too dear for me, the next nearest Tirnigy were short for the pre-drilled holes, but with one end fitted, the other fitted to the frame hole edge so with washers was secure.

 

Then the ESC I'd bought was getting far too hot, and resetting when the throttle was closed, forcing a different ESC to be used.

 

It was completed on Sat and hover tested Sunday afternoon once the wind died back a bit, and proved easy to get trimmed and quite quiet.

 

So far, so good.

 

Hopefully tomorrow it might get a proper flight in the wide open spaces of Poling.

[Bravedan 106]

So I arrive at Poling, and the grass (mostly tall stalky weeds more like) were so long I could not fly, so back up to Fickelshole, which was nice and short.

 

I have three sets of cells (2 of 2300mAh 3S per set), and I flew all three sets, being conservative as to duration till I know what rate I'm draining the cells at.

 

It's very enjoyable, nicely stable but at the same time lively.

 

Just briefly hovered the least used set in the garden with my DPC connected before recharging them, and got the following figures from a stable 1 metre high hover with one power pump.

 

Time: 0:41

Rate: 3 SPS (Samples per second)

Charge: 153 mAh

Battery Efficiency: 98%

 

Max Current: 15.44 A

Avg Current: 13.37 A

 

Max Voltage: 21.74 V

Avg Voltage: 21.22 V

Min Voltage: 20.69 V

 

Max Power: 327.57 W

Avg Power: 283.39 W

 

Just gone over it mechanically and so far so good, no issues emerging, nothing loosening.

[Bravedan 106]

Incidentally, the complete 500 Class Heli inc gyro, servos and ESC/UBEC and motor, in fact ALL bar the Rx and batteries, came to £158.77.

 

The basic kit came with all the "essential" upgrades/fixes with one exception, the front tail belt drive with metal gear, which I added at purchase and was £3.75.

[Bravedan 106]

Had a few more flights now. Yesterday was very turbulent, yet it was pretty easy and stable.

 

Here's what it looks like. This is with the "supplied" plain white flexible plastic canopy with some vinyl I added. I have a flasher detailed scheme fibreglass Canopy (a massive £6).

 

 

[Bravedan 106]

Using two separate 3 cell batteries, there's a slight concern they won't drain equally, so have done a few test flights.

 

Just as one example, flown only to very first signs of drop in power, one pair of batteries took on recharging separately 2049 and 2050 mAh. Quite well balanced then!!!!

[Bravedan 106]

Here's a pic with the FG canopy.................

 

 

How they do those canopies for the money I'll never know..............apart from the five differing paint colours you see, the whole lot is oversprayed with a thinned out metalflake to make it sparkle.

 

All for currently £7.77 in UK.

 

One thing to watch for, the HK FG canopies are thinner and more pointed than the plastic ones, so battery space is tighter.

[Rich 26]

Wow, nice chopper Dave... Looks miles better than that pants canopy...

You got this thing running on 2 x 3S at the same time (Tight wads 6 cell)???

 

All that for under £160?

[Bravedan 106]

So, after lots and lots of use, eventually it started playing up a bit, traced to the swashplate getting too much play in it from wear on the bearing and housing.

 

Keeping the "extreme budget" bit going, I bought a UK sourced but HK swashplate for under £12...and it's back flying well again.

 

I think it's amusing that on a model criticised by many as weak, unreliable, and made from rubbish plastic, it's run for ages and ages totally bullet proof, then the first part to eventually wear out is the all metal bit!!!

 

Anyway, it's so impressed me over the year of heavy use that HK500 kit No 2 has arrived..........this one is metal/carbon, as GC seem to no longer bother with the composite one, it's been zero stock for six months or more.

 

GC had no motors either though, so have ordered the "hot" Typhoon one from HK direct.

[Bravedan 106]

Built the new carbon one, then on the second hover I ventured a little "power pump"..and that super powerful motor just removed most of the teeth off the main gear in nanoseconds..................

 

Now has a carbon loaded one on there............ That was several increasingly violent flights ago, and so far no further issues.

 

Have not yet quite got it dialled in as well as the first one yet. Spot on blade tracking is proving a pain, might have to change the ball joints on the links, as the ones fitted are "one full turn only", and one turn, even on the "fine" side of the lever, is too much in one go. Sceadu 50 ones fit, so that's what TO do when I get the time and enthusiasm to set it all up again.

[Bravedan 106]

So, Update time.........

 

BOTH 500's are still with me, still active.....NO spares added at all since the swashplate wore out on one in July.....been used at least one day a week for multiple flights on average since then....so much for HK 500's being sub-standard compared to the "genuine" TRex product, Eh?

 

Last week I broke one canopy post. My fault. I have a "spare" complete kit (which cost not much more than a set of decent blades!) so just swapped for now.

 

I'm flying them 6S, and up to now have been using my 450 batteries in pairs, which are only 2300mAh (Tipple), relatively small for a 500 when paired. After lots of use singly on the 450s and in pairs on the 500s, I have unsurprisingly had three failures in very quick succession. These batteries seem to have a particular failure type, in that a cell will fail to 0v measured on the balance output but the pack will still conduct across the power output as a 2S, so assume the cell is shorting (but no sign of stress in terms of heat or becoming an incendiary when this occurs!!

 

Bigger sized Tipples have a minor issue anyway, in that they swell during use if use even if only at medium C levels relative to their rating and so well within their current capacity.........NOT the cells...........the sleeve and under tape covering creates an air seal, traps air which expands, the cells themselves do NOT expand visibly.

For loads of cycles the covering swelling will completely disappear and the pack regain shape as the air cools after use.

This is OK IF the housing they are in doesn't constrain them too much!! No problem in a Heli but in say my Alpha Jet EDF it sometimes needs a short wait to cool enough to get a cell out again!

 

Anyway, the Big Fish has some Gens Ace cells in as a trial, so I have bought a pair of 3300 3S and a single 4000 6S. Have only flown the 4000 briefly so far just to check the extra weight is OK, which it seems it is. The weight, size and lurking hidden energy of a cell that size is a wee bit sobering. NOT one to take ANY liberties with then!!!

[Bravedan 106]

So, last Saturday there was little or no wind, so I thought I'd give the 500's an outdoors session rather than the 50's.

 

First flight, using the newer carbon one, lifted off, hovered, started to slowly move into forward flight, when it ever so slowly but uncontrollably pirouetted near 180 degrees and then smacked violently in tail first. Oh Bother says I...........

 

Didn't fly the older one, flew a 50 and a few light wind preferred EP planes (well, quite a few planes!!), no issues after that.

 

Not able to tell what caused the piro crash.

 

Today, took the older 500 and a 30, plus some "planks".

 

Flew the older 500, first flight, lifted off, hovered, started to slowly move into forward flight, when it ever so slowly but uncontrollably pirouetted near 180 degrees and then smacked violently in tail first. Oh Bother AGAIN says I...........

 

The 30 and some planks flew perfectly from that same Transmitter, and both heli's were fine last time out.

 

I dunno........................

[YellowAlert 0]

I think you fly Futaba 401's anyway, but just in case...

 

I had a cheap and nasty (early Align) 401-clone gyro that drifted fairly quickly on cold days, never quick enough to cause an accident but I had some close shaves. It was near-tolerable on warm days but didn't lock well at the best of times so I got rid.

[Bravedan 106]

Both on genuine 401s.

[Jimbo 0]

But still could be the cold? Maybe worth performing some gyro tests?

[Nutz 0]

Most gyros including the Futaba range need about 10 minutes in the ambient temperature before you use them or you might get drift issues.

[Bravedan 106]

But still could be the cold? Maybe worth performing some gyro tests?

 

Well it could be I guess, but with the engine powered Helis showing no similar issues, yet subject to the same temps both in storage (unheated garage) and use, it highlights on the HK500 and I'm wondering of there is anything on the chassis that is temp sensitive. I give them stabilisation time before flying.

 

Countering the gyro being the cause, the older one went all through last winter with no issues.

 

Anyway, the older all plastic fittings 500 is def no more, too much damage to worry about repair.

 

The metal/carbon one is repairable, the tail end drive requires complete replacement, the boom, supports and main frames are OK, at the front end only the tail drive gear is stripped, and the auto-rotation gear will need changing as a precaution. Since a complete kit is £79 currently it's quicker to just build another and just strip off the good bits from the crash as emergency spares

[Bravedan 106]

I have belatedly (and therefore stupidly!) realised that I may have experienced what I'm now reminded has been the bane of some people with the TRex 500......static generated from the tail belt...................not something I'd had an issues with before over several years so had got forgotten.

 

Just read someone's post and they had 2.4GHz lockouts caused by it, and basically that's what happened, lifted off, and lost control with tail drift

 

Thinking about it, it was the ideal weather conditions for it. SIGH...................

[Bravedan 106]

Built these since it was raining......................... and raining............and raining............

 

 

From the left:-

 

1. HK500CMT direct from Hobby King, Carbon/Metal, GY520, full digital MG930s and coreless tail servo, Typhoon 500 motor, Scorpion 80A ESC.

 

2. Giant Cod "HK500GT" - Bought last week on pre-move clear out for £45. Carbon/Metal, GY401,MG930's and EX9257 tail, 500 motor, HobbyWing Platinum 80A ESC.

 

3. Giant Cod "HK500GT", Carbon/Metal, HK401, TY53317M, MG930 tail, Soft tune wide response 500 motor, HobbyWing Opto 60A ESC, 5A UBEC. Twin white LED headlights and flashing red top LED.

 

While setting up No1 for pitch, tracking, etc, I flew it on a single 2300mAh 3S for some time, so its pretty free running!!! (Will of course be 6S and 2700mAh)

[Nutz 0]

Today I built and set-up a trex 600, put it into a MD500 shell with nav & landing lights, rebuilt the rear of my buggy and redone the stars on the mustang, so I think tomorrow will be Xbox all day..............................

[Bravedan 106]

Tomorrow I will be building a Sky Surfer, and painting the body on my 450 Sikorsky/Westland Dragonfly..............

 

but the Sky Surfer won't be made from EPP, won't be pusher, and will be elevon only...........

 

What will it be?