ozghost1952
Heliman
Location: Melbourne Australia
| About five months ago I offered to build and review the Dominator 20cc. I paid for the kit, the standard sport model which was discounted as an evaluation model. I have suffered systemic failure of multiple components and am wondering if I have just got a dud kit or if there are deficiencies in the design and specs of the model and it is not yet ready for the market
Before I am accused of QWW bashing let me establish my credentials I am a qualified engineer and a certified model helicopter instructor and have been building and flying model helicopters for more than 30 years. It could be reasonably held that I understand strength of materials and mechanical design and that there is a good chance I know my way around building and flying helicopters.
I struggled with the initial build because the parts did not fit well I only got the main and tail drive gears to fit when via a PM I was advised to place the auto clutch assembly in a vice and tap the top with a hammer till the gears did not foul (hopefully it stays this way else I am in trouble!)
After that I continued with the construction with a file, drill, dremel and red loctite as part of my tool set to get things to fit. When parts did not align the standard advice from QWW was to file the holes bigger but in some cases this would have been two to three millimetres not the ideal situation for a production kit.
There were also items missing from the kit especially spacers. With the pre assembled items I was also advised via a friendly PM to take them apart and ensure that the screws were tight and to remove excess loctite fouling bearings. Other things that concerned me were the lightweight feel of the head, and the lack of flat spots to secure grub screws on most shafts. I also could not use their paddles as they were significantly out of balance and I changed the flybar arms as the aluminium posts again did not seem strong enough for the gasser. (I understand that QWW use the same sport head throughout their range from little electrics to the large gassers)
Anyway, after a frustrating build the day arrived to start the heli. Spooling up to lift off immediately showed up a total lack of tail control. The sport tail did not handle the centrifugal pull of the blades and when spinning, the servo was not able to move them. No Problems said QWW and promptly sent (and charged my credit card) a metal tail blade assembly. At that stage I also started to have concerns with the sport head as I was getting high speed shakes. After fitting the new blade assembly the tail now worked but the head was still causing vibration.
A week later while in the air the sport tail gearbox broke off on further inspection it was easy to see the stress crack propagation from a milled slot to a point where the aluminium casing was paper thin. Again, QWW came to the rescue with the CNC tail (and charged my credit card with the full price not the upgrade price) and at this point I must add every time something was wrong I was told that we have sold thousands of whatever and no one has ever had theses problems. (I was never refunded with any of the failed components)
So, $120 later with the CNC tail fitted (again with mods to get things to fit) I tried again. There was still a significant amount of shake and lots of white powder around the main gear and pinion. It was a battle to get the gear to run smoothly trying to find a balance between smooth mesh and gear backlash and it was then that I realised that the pinion gear was different to any other of the helis I currently fly the gear profile looked incorrect and to add to my troubles the white delrin gear was out of round due to the four mounting holes drilled inaccurately. I took both to my friendly machine shop and they trued the pinion gear which made the mesh more consistent. Again all the advice coming out of QWW was it will come right after a few flights just be patient.
At this stage I enlisted the best brains in the club to help me internationally acclaimed pilots. They test flew the heli and tried to get rid of the shake tried different blades, different O rings but the advice was all the same it was only fit for the rubbish bin.
Undeterred, I battled on and as I had a raptor 90 head ready assembled I fitted this and the shake immediately disappeared. I also replaced the main shaft and the tail shaft with a hardened steel ones the tail shaft is too soft I had one bend due to a slightly uneven landing. The main shaft is also too soft it burrs too easily causing problems when removing the shaft though the bearings something I have been doing on a regular basis!
So at least I was now able to fly the machine without things falling off and without the thing shaking but still with noisy gears that needed adjusting after every flight. When I disassembled their sport head, I did note that the two aluminium blade holders were slightly different weights but more importantly the flybar carrier was off centre and that was the most likely cause of the shake. QWW offered to replace the head but I am wary every time they replace things they bill my credit card and the freight charges are quite steep as there is no longer any Australian supplier for QWW (no repeat business!) . The Raptor 90 head looks and feels the right size for a 60 size machine and is tried and tested so I will leave things be.
With the machine flying, I was still not happy with the gear noise, so I got my friendly machine shop to cut me a new 12 tooth module 1 gear. At the same time I got them to make me a new clutch bell to the exact same internal dimensions but with a longer thread for the pinion and the correct proportions to match the holes in the frame without dropping bearings, filing the side frames and red loctiting them in place!
But alas I had to delay fitting the new pinion four weeks ago my top frames cracked in the air and the main gear stripped (my local experts reckon the constant percussion from the incorrect gear profile was the likely cause) . QWW immediately told me they would replace the frames and gear and look after me but when they had not arrived after two weeks admitted that someone had "forgotten" to send them. They finally arrived only to find that they had sent me the wrong ones and Im sure you know whats coming billed my credit card again. When I queried the Invoice, Chris told me that as they had never had these fail before he was instructed by Irwin to bill me showing a lack of integrity telling me he will replace the frames but telling his staff to bill me. At this point I ask with tears in my eyes I dont see many other QWW 20cc gassers flying out there it is a brand new model I had not even done 10 flights with the gasser and already they have enough confidence to tell me that it was always something I had done wrong so I must pay for it. I would also like to add that I had ordered some other small parts and rather that include it all in one parcel they posted them two days apart with the postage almost equalling the value of the parts I had ordered.
The correct side frames and a new main gear finally arrived but I still was not ready to fly the new main gear was approximately 1.8mm out of true so to get the pinion gear mesh correctly I redrilled the four bolt holes in between the other holes and even by hand they are more accurate the production model.
So, at last with many non QWW parts, my heli was finally flying with minimal maintenance between flights but how wrong I was. Last weekend the clutch fractured and guess what because I was not using their clutch (my new one was identical inside ID with the identical liner and because no one else has ever had a failure (this clutch was designed specially for the 20cc gasser joke!) QWW are not interested in helping.
So, where do I go from here? I am the laughing stock at my club with people wondering why in this day of professional kits and reliable machines would I punish myself with substandard equipment, questionable after sales service and no local support?
To make things worse, a colleague at the club bought a Spectra G and flies the pants off this machine every week no problems no component failure just plain enjoyment. At the time I thought QWW was good value for money but I have now spend significantly more on replacing defective parts than what I would have spent on a Spectra and I dont think I am at the end of the road yet.
I hope that anyone reading this will think very carefully before making their choice of gasser machines.
Regards
Jeff
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