New Gasser

[chrisleematt21]

I have been following a thread on faceBook about a 60cc Trex 700x conversion (Blackoutmods), and it has sparked my interest in gassers.

I like the idea of a Nitro / gasser as i don't have to wait for lipos to charge and when I get to the field I can be up and flying in 10 mins.

BUT recently I have had a lot a grief with my nitro, and its spent quite a lot of time and money being rebuilt.

What are gassers like in comparison to a nitro?
Do they fly as well?
More vibes?
What is the performance like?

[trillian]

The thing about comparisons with nitro is that it's going to vary depending on what engine and what percentage fuel in what airframe. So for example, a 105 in a light airframe at high nitro, high revs is going to be a very different experience to a .91 engine on lower nitro in a heavier airframe.

60cc is huge in gasser terms. I'll have to check out that FB page, and I'm sure there will be something about it on Helifreaks as the gasser forum there is quite active.

I can tell you my experience. I used to fly .91 nitro helis on 15%, sometimes 20% fuel and my flying is smooth big air and a bit of F3C. The gasser I have now is an RMJ Raptor E700 conversion with a Hanson 300 (roughly 30cc) and a TRM pipe, so not by any means the max possible even out of 30cc. For me it is every bit as capable as the 91 nitros I have owned. It's a bit on the heavy side at around 5.6kg without fuel but I have a longer boom and SAB 730s and it doesn't subjectively 'feel' heavy in the air. It's the gasser I always wanted, it does anything I want it to do and does it all pretty easily. I'm running at 1800 in idle-1 (I think I've got +/- 11 right now). It took me a little while to get used to the tuning and I was being very cautious in the beginning as I didn't want to go lean, but they're pretty easy to tune and don't require fiddling after that.

Regarding vibes, mine is quite smooth, no more vibes than .91 nitros I have had. I also had problems with a couple nitros some years ago, I had a YS91SR go lean and cook itself and I had an OS91 ring stick once which ruined the piston and liner - this is one area that the Zenoah gasser engines are vastly superior, they are darn near bullet-proof, they're a bit agricultural but the upshot of that is long lifespan and very high reliability, no rusty bearings either!

[chrisleematt21]

\to add to my original post, I am flying a Trex 700XN with an OS105 on Opti 25% @ 1950HS

[chrisleematt21]

Here is ta direct link to the fb page

[trillian]

Here is ta direct link to the fb page

Yeah I had a look. I remember them mentioning something about the idea a while back. It will be interesting if they can get it work but it's an experiment at the moment.

The two problems were always cooling and the clutch, and the Zenoah RC engines solve both of those, they have a big fan and cooling shroud and a sturdy clutch that operates at the correct RPM.

I'd say you may get the performance you're looking for with a Hanson or TRM and a quickdraw pipe. There are some videos out there of gassers being flown quite aggressively so you can get some idea.

[JoeBailey]

I had a minair spectra G. It fly's very different to a nitro mainly due to the weight and low power output of the stock 23cc zenoah in it.

The best way to get a feel for it is to set a 700 electric up with 1500rpm and fly it. In the right hands it will do the book. But make a mistake and snatch at the controls and will bog and struggle.

Tuning is pretty straight forward. If I built one now I'd by a TRM motor as the info on tuning and maintenance, running in etc is easily available.

[trillian]

Here's a Goblin conversion with a TRM 300 and quickdraw pipe: https://www.youtube.com/watch?v=-I-Smg04uEk

[chrisleematt21]

Here's a Goblin conversion with a TRM 300 and quickdraw pipe: https://www.youtube.com/watch?v=-I-Smg04uEk

Doesnt seem to be lacking in power, or havè any power to weight issues

[trillian]

Doesnt seem to be lacking in power, or havè any power to weight issues

Yeah I think the Quickdraw pipe might be the key thing because it has an expansion chamber and can be tuned. I would guess he's running somewhere around 14k rpm. I'm running mine at 12,600 rpm so it's just chugging along and not at full chat and it just pulls through all the kinds of moves I do.

..Then again, here's a Synergy 766 and it has the regular TRM pipe and longer blades: https://www.youtube.com/watch?v=YUOPvuwDpLY

[Guest]

Why aren’t you all in bed at that time ;-) what am I missing? Midnight flying sessions.

MJ