Synergy N7 OS GT15HZ conversion

[kev20009]

Hi guys,

Been looking for a canopy for my goblin build, and last night, fast lad had a clear out, got 2canomod for £43.00 booms where £19.00 so well chuffed,

They where selling trex from £4.00 to £14.00 and canopy cover £4.00

Kev,

[DaweMD]

Hey Mitzu, what are your needle settings? Seems like I am chasing my tail. I start out with stick settings on both needles. Fire it up and it hovers for a bit than powers out. So land and go leaner on low needle. I keep going and at one point I am at about 1 turn out on the low. Seems to run ok but when I land it idles than shuts down. It makes some effort to start but won't completely catch. Reset the needle back to stock and than it starts up after a bit. I than tried going richer from stock settings and still no luck. I have not adjusted the high needle at all. Pulled the plug and it looks carbond up. No wet oil.

Your thoughts?

[Sowa]

Did you flip the carb on the motor?

[DaweMD]

Yes I did, and I filed down the engine fins so the carb could fit on there without any interference. I just got my hatori pipe in today so it is going on for the next flight. I am also running a blue coloured 2 cycle synthetic oil made by evolution.

[brw0513]

Originally Posted by DaweMD

I am also running a blue coloured 2 cycle synthetic oil made by evolution.

Is it possible that Evolution oil is CoolPower Blue?

I've been wondering for a while.

[Sowa]

Originally Posted by DaweMD

Yes I did, and I filed down the engine fins so the carb could fit on there without any interference. I just got my hatori pipe in today so it is going on for the next flight. I am also running a blue coloured 2 cycle synthetic oil made by evolution.

Gotcha, sounds like an air leak. These motors can be finicky at first. I had similar issues with my 90 version GT15HZ in the N7 in the beginning. It turned out I was not bottoming out the needles all the way when resetting them. There was a rough spot on the threads that I had to turn hard enough to go past. Other's have had similar issues.

1) check for any air leaks,
2) check for a loose muffler
3) check spark plug gap and condition of spark plug.
4) check that the spark plug boot is properly seated.

On stock needle settings if it dies in a hover then the low speed is too rich. Your fouling the plug out, and it won't restart without cleaning the plug. For the 1st tank I'd hover the heli until it would foul the plug, clean it, lean the low and then repeat. Continue doing this until you can get a solid hover, keep an eye on temps. You should notice an increase in time before the plug gets fouled. I use iso to clean my plugs.

If you have leaned out the needle to the point that the engine won't idle then you have gone to far. There's a small range in the low speed needle where the motor is happy And idles well. I would say about a 30 degree window, the position of this window is affected by the high speed needle setting.

Hopefully this helps, I've noticed the os boost pipe requires much less fuel than the Hatori. In all honesty I was a blade width lean on the LS with the Hatori from stock settings. Motor ran about 220F with good power.

[DaweMD]

Thanks Mitsu, where did you end up with the high needle setting?

[Sowa]

Didn't even touch it with the Hatori pipe. With the boost pipe it was rather lean. I don't remember exactly but I want to say around 3/4 turn in, once the head speed get's picked up it will need more fuel though.

[DaweMD]

This next flight will be the first with the motor fins filed down as well as the hatori. I also replaced the gaskets on the carb before reinstalling this time even though the original ones were still in good shape. Another silly question, what is iso?

[DaweMD]

What did you have for throttle curves? I was going to aim for 1600, 1750, and 1850. Once you have a good hover i am assuming you just do some full power climb outs to see where the high needle needs to be?

[Sowa]

Originally Posted by DaweMD

This next flight will be the first with the motor fins filed down as well as the hatori. I also replaced the gaskets on the carb before reinstalling this time even though the original ones were still in good shape. Another silly question, what is iso?

Isopropyl alcohol

Originally Posted by DaweMD

What did you have for throttle curves? I was going to aim for 1600, 1750, and 1850. Once you have a good hover i am assuming you just do some full power climb outs to see where the high needle needs to be?

Normal 15, 37, 42, 48, 100
Idle up 100, 62, 43, 62, 100

Idle up worked ok, it may not be the best curve as it would bog in full pitch climb out after 5sec. Not sure why but the gov cleaned that up. Crank up the spoolup rate with the GT15HZ, it works better with a higher rate otherwise it hesitates.

I would get a gallon or so through the engine then just switch to the ikon internal gov. World of difference.

Hatori pipe uses more fuel, you should get good performance on stock needle settings. Just wait to lean out the motor until you get up past 1900rpm on the head. It starts to use a lot more fuel past that.

[DaweMD]

When you say spoolup rate i assume you mean the gain in the IKON software?

[Sowa]

Yessir

[DaweMD]

Cool, thanks for the tips.

[brw0513]

mitsudriver274,

Are you still flying this N7 conversion? If not, was it because of any particular deficiency or did you just move on to the Goblin gasser?

What size main blades did you use?

It looks like the N7 clutch, bell, fan and fan shrouds are easy enough to put in an N5 airframe. The standard ratio would be 8.5:1. What do you think of this as an option?

[Sowa]

I'm not flying the N7, it was sold to DaweMD. I had two GT15HZ powered heli's and wanted to try a zenoah, I had been bugging Carey about a conversion since last march. I got a new job and it allowed me to finally be able to afford a 700 goblin gasser.

The GT15HZ does ok in a 700 class heli, but it really shines swinging smaller blades. I was running 690mm blades in the N7.

8.5:1 will really wrap the motor out at 2200, 18.7k, I don't think it would last long. That's the issue with the N7, is the gear ratio. 8.1 stock (I believe) worked out very well swinging 690 and 1950, which was 15.8k at the crank.

I think a GT15HZ powered N5c would be a killer setup. However, the gear ratio and getting the n7 bits to fit will be a pretty large hurdle to jump especially since the frame width is different between the two.

I've been bugging Matt Botos about this but he doesn't seem to care for gassers much, the market is just too small.

[DaweMD]

I absolutely love the N7 with the Gt 15 Hz. Very nimble and light feeling. I have a goblin 700 gasser with a Hanson 30 engine and a trex 700 with a hanson 27, so compared to both of these the N7 feels quite light in the air. In my opinion the N7 is a great sport flyer with the occasional flip and roll but if you are a big 3D guy than you will need lots of collective control to not over work the motor. I try to keep the engine RPM around the 14-15,000 area which is pretty much its limit. According to my calculations that sits at the 1950 headspeed.

[DaweMD]

You are right Mitsu, I was off on my numbers. 1950 is the absolute max i would want to run on this engine.

[Sowa]

Maybe

I've ran a few tanks, probably the last quarter gallon through my gt15hz 600 at 17k. From experience the motor ran very well with the Hatori pipe that high, pulled harder and recovered better.

Hopefully with some careful massaging I can make it reliable at that engine speed.

The N7 sure was a fun setup! I definitely miss that one in my fleet.

Edit: From my previous posts I was actually running this airframe at 2000 with the gt15hz, that is 16.2k at the crank.

[brw0513]

DaweMD,

Were you using 696mm main blades on your N7 with the GT15HZ?