Eury
rrProfessor
Location: Ankeny, IA, USA.
| I'm back, worked on it some more today, I've been very busy, I apologize for the amount of time it's taken.
I checked out the new tail drive bearing blocks and shaft that I mentioned I had been sent by QWW, and the new ones appear to be to spec, the bearings are centered, and the flat is on the shaft, as depicted in the instructions. Much better.
Also, I received a PM from a QWW employee regarding my post about the size of the body mounts. He checked the OD 20cc that they have in the showroom, and sure enough, it has 50mm mounts on it, same as what I have. He told me that the manual will be changed to reflect that, as it is a misprint.
Started in on the engine install, as well as the clutch. This is all preinstalled on the heli I have, but I'm going through it to check for fit and accuracy. This is out of sequence with the manual, as I am going taking pictures and going through fasteners etc fromt he top down on the engine. I'm not going to pull the fan assembly off, or do any major disassembly of the engine install, just check fasteners for tightness/locktite, and the assemblies for fit and correct assembly.
First impression of the clutch assembly is that it's heavy duty! The outer edge where it engages with the liner is nice and thick, and appears quite strong, and it has removable weights inside it to adjust the engagement point. Very cool, I've never had the desire to change the engagement point of a clutch, but if I wanted to, it could be adjusted with this setup. Nice design, I'm impressed. Good job on that QWW!
Next I wanted to touch on the engine itself. Most gas powered helicopters out there use the G231PUH, G260PUH, or some variation of that theme. Those engines have a magneto ignition that works well, but has some real disadvantages. The timing is fixed, so it is only going to perform ideally at a certain RPM range, starting can be a bit more difficult (although certainly not hard), and they require a heavy flywheel. Their big advantage is that they are simple, inexpensive, and tough. Same tech you've got in your weedeater, and chainsaw.
The G20ei that the OD 20cc uses uses an electronic ignition, like most high end gas motors today. The electronic ignition has automatically adjusting timing, so it always sparks at the ideal time (in theory), it gets slightly better fuel economy, it doesn't require a heavy flywheel, it has less vibration, and it's easier to start (again due to the adjustable timing). Also, the 20cc uses a magnesium case which cuts weight down quite a bit. However, the disadvantage is that it requires a power source, in this case you are going to have to carry a second battery on the heli to power the ignition, and a switch to turn it on and off. Also, you have another box to mount, and more wiring. Ideally you keep the ignition box as far away from radio components as possibel as it does generate RF noise. This is the same tech as the big expensive airplane engines like those made by Desert Aircraft and 3w, as well as what you've got in your car (albeit much simpler than a car).
Apparently the factory magnetic pickup on the G20 engine is incompatible with the helicopter mounting, so the manual has you drill a hole and install the magnet in the fan hub. Not unlike how you would install a governor magnet. This was already done on the engine I received, as you can see in the picture.
The heli also comes with a nice extended throttle arm that is installed after flipping the carb 180deg to get the arm in the right spot. Nice piece, feels pretty secure once it's installed, although it doesn't run quite true, I need to pull it off to see where the fault lies in the assembly.
Now for my bitch of the day. I expressed my concerns about the nice screw case not being organized, and I've ran right up against it. The first step where I have to take a part out of a bag, assemble it and install it on the heli took me 10 minutes before I got pissed and put it down. I'm looking for 4mm x 6mm socket head screws. I'll give anyone who can spot one in this picture $100. Seriously. I will.
If I'm going to get this together, I'm going to have to dump all the screws out, and separate them in something like an ice cube tray. I know it's possible, but it really shows an area where QWW is behind the competition. Most helis have all the screws bagged for assemblies. So if this was a Hirobo, I'd be on bag G and there would be 15 screws in it, so the 4 I need would come quickly. The RJX Xtreme 50 I just built has all the same size screws bagged together, so if I needed a 3x10 screw, I just grabbed that bag. This is not a good way to do it. I appreciate the nice screw case, but it needs to ahve a lot more compartments, and have them sorted by size.
Nick Crego
Back off man, I'm a scientist. |
