600N Upgrade Engine Fan Comparison

Written by Tony Chaveiro Monday, 22 October 2007 00:00

Geforce HEV2 Fan

Physical characteristics

CNC machined, edges are chamfered and polished, has an outer rim to increase strength and durability. It has two inside pockets to hold most current magnets and an anodized finish. It weights 23.8gr Installation: This fan has airfoil style type fins to reduce engine load and still provide adequate cooling. It seemed to be quite effective during the tests even though the reader should take notice that needles had to be adjusted accordingly. Balance was spot on and there was no noticeable run out. I did however notice a slight vibration while I was spinning the fan at high speed on a high point balancer but careful investigation revealed that it was in fact the metal hub that was out and not the fan. The metal fans just magnify the problem by being heaver than the stock plastic fan. This slight vibration was felt with all tested fans. I did have a small issue when I installed the fan as I needed to readjust the governor sensor distance since the HEv2 fan is beefier than stock. This wasn’t a big deal but it may be problematic for some types of sensor installations.

Flight report

In the following charts you may appreciate the engine performance during a set of tictocs, back flips and other acrobatics. As you may notice the temperature varies quite a lot from maneuver to maneuver. For instance, I noticed that the engine cools a lot while inverted. I couldn’t find a reasonable explanation for it but it does happen. I would also like to note that since I’m only using 20% nitro, my engines usually reach peak performance at 239F (115C) and it isn’t unusual to hit the 248F (120C) mark during the summer peak. My last Hyper lasted around 320 flights before it needed a piston replacement due to a defective carburetor o-ring which made the engine hit the 394F mark and then die in agony. The rear bearing is still the original that came with the engine so I’m pretty relaxed running those temperatures from past experience. As you can appreciate on the RPM chart, the engine performed consistently with the defined target rpm (17000) and rpm losses are minimal (between 500 and 1000 rpm mostly) which doesn’t reveal much when not compared with the 3Dx and SHO charts. The engine tuning required minor adjustments on the main needle (4-6 clicks richer) to keep the temps under control and no significant reduction in mileage was noticed. This fan lets you tune the engine just like almost all fans currently used in rc-helicopters.

Pros

Nice quality finish, beefier than stock and performed as expected. No flex could be noticed and once the magnets are in it they’ll stay there. Engine load seems to be minimal as the governor doesn’t work all too hard to keep rpms at the defined target range. The use of the fan doesn’t change the way of tuning the engine.

Cons

Magnet pockets could be 0.1mm deeper to make sure the magnets will flush perfectly with the surface using thicker adhesives. I really wish Gforce could make a 1 mm hole in the pockets so one could press out the excess of glue and poke out the magnets if needed. Once they are in, there is no way to get them out without damaging the fan. Make sure your magnets have the correct polarity before installing them. A sensor distance readjustment over the stock fan is needed.