trex 700n project options gasser maybe

[andypaddlerking]

Hey guys hope your all well.

I'm looking for advice about potential project/conversion options for an old v1 trex 700n air frame.

I have a complete spare air frame that rather than use as spares id quite fancy doing a Gasser style conversion with it. I already have a 700 nitro and electric models which work perfectly so not really after another one of these but i quite fancy trying a gassser build out. I like the look of the standard heli bug conversion like this

Helibug HB7-RC Gasser Conversion for Trex 700

Sadly though it doesn't look like you can get the conversion kit for this anymore from new. Does anyone have a conversion kit tucked away somewhere they fancy giving up for a price?

Otherwise most of the other conversions available now don't really use the align v1 parts and would be very expensive to build a gasser using a blackout mods conversion as id need loads of align parts also.

The other option i know of is to try using one of the os gt15hz engines which would be a simple drop in fit for the air frame but ive heard people have had issues with this engine. it sounds like there were some design flaws with this engine but they have been corrected in the version 2 of it but i cant find out people verdict or experience of it.

Any way what do you guys think is my best option moving forward for me.

cheers

Andy

[trillian]

I have an engine (Hanson 300) and a complete kit for the Raptor E700. I also have a custom gasser frameset for the Trex that I got in a small job lot.

What kind of main gear does your 700n have?

[andypaddlerking]

Hey buddy i like the idea of the frame set for the trex 700 you mentioned do you have an pics? what would be the best engine setup required for it as i dont have any gasser style parts yet just the standard align clutch style setup.

my trex currently has the mod 1 gears i believe.

Cheers

Andy

[trillian]

I'll get some pics today and round up anything I have that goes with it. I think the pinon is a straight cut gear (mod 1).

The best options on engines lie with two engine builders in the USA, Hanson and TRM. I have had a few of both. The spare engine I have now is a Hanson 300, which is the Zenoah RC style engine and I have the TRM pipe. (I also have a Hanson PUH 26cc engine but most kits these days use the RC engine with the Zenoah clutch).

My first gasser was a Hirobo Bell 47G, then I had a Kalt GS Baron but it was obsolete when I got it. So I got a Century Predator and it was great for many years and then they discontinued it, parts became harder to find etc. so I sold the airframe. I also had a Robbe Futura with a Zenoah G23 but it was very underpowered. A few years passed and then I got a Helix Trex conversion, which I was quite happy with. So when the RMJ Raptor conversion was being developed I built one and then sold the Helix simply because I didn't need two gassers and I had a lot more money in the Raptor (which I still have).

Hey buddy i like the idea of the frame set for the trex 700 you mentioned do you have an pics? what would be the best engine setup required for it as i dont have any gasser style parts yet just the standard align clutch style setup.

my trex currently has the mod 1 gears i believe.

Cheers

Andy

[andypaddlerking]

[QUOTE=trillian;1253471]I'll get some pics today and round up anything I have that goes with it. I think the pinon is a straight cut gear (mod 1).

The best options on engines lie with two engine builders in the USA, Hanson and TRM. I have had a few of both. The spare engine I have now is a Hanson 300, which is the Zenoah RC style engine and I have the TRM pipe. (I also have a Hanson PUH 26cc engine but most kits these days use the RC engine with the Zenoah clutch).

My first gasser was a Hirobo Bell 47G, then I had a Kalt GS Baron but it was obsolete when I got it. So I got a Century Predator and it was great for many years and then they discontinued it, parts became harder to find etc. so I sold the airframe. I also had a Robbe Futura with a Zenoah G23 but it was very underpowered. A few years passed and then I got a Helix Trex conversion, which I was quite happy with. So when the RMJ Raptor conversion was being developed I built one and then sold the Helix simply because I didn't need two gassers and I had a lot more money in the Raptor (which I still have).[/QUOTE


yeh that conversion frame sets sounding like the one that will work best for me does it come with pinion clutch stuff etc or does it just run the align set up?

cheers

[trillian]

OK, here's the Trex frame I have. I will ask the person I got it from if he has any more info. I'll see if I have a main gear that goes with it.

[trillian]

The pinion is 17 tooth, so I assume it needs the 115 tooth straight cut main gear.

I found the prototype thread: http://www.rcheliaddict.co.uk/gasser...ex-gasser.html

[electricsceadu]

I also run gassers
Hirobo Bell47 g2 with the TAS 24 engine

Vario R22 and Bell47G3
and a benzin trainer all powered by the Zenoah RC engines
pod and boom gasser id go with the benzin trainer every time

if you are interested I do have a Century preditor air frame with engine less the tail and canopy, it came in an EC135( which the benzin trainer is going to be used to power it)
make me an offer if youre interested in the preditor

I have seen the OS15GT running in a pair of TREX 700's both engines seam to run well be do get a little warm and lose power
before I knew them both engines went back to ripmax after failing, they both had one of the circlips missing on the piston with the pin moving and scrapping the liner

[andypaddlerking]

Hi all

I've received the frame and parts thanks trillion. I've started the process of sussing out all the parts etc and what ill need to do to get it working smoothly. I think I've worked out what ill do with the clutch bell assembly using the stock zenoah clutch using a couple of align bearing blocks for support. i should be on a role with it now so cant see any more big stumbling blocks holding me back.

ive been doing a bit of reading up and research on the engines and found these on my travels.
https://www.ebay.co.uk/itm/29CC-Rc-2...53.m1438.l2649

they look just like a copy of the zenoah engines, has anyone ever seen or heard anything about them? I've done a bit of engine tuning work myself so i'm interested in trying to do the tuning work myself so just looking for a standard engine rc format 4 bolt style engine to start with and see where it takes me.

cheers

Andy

[theonlygk]

Hi Andy,


Tuning wise if all else fails you could just change the carb to a walbro and I'm sure it would run fine.

My only concern with that engine would be vibration?

Vibration could make the model fly like a bag of nails if its too bad but who knows I would be intrigued to find out how it goes

[andypaddlerking]

gasser update

Hey guys


I have been making good progress with my gasser build. I'm still waiting on a few parts to arrive from china which are the 2 upper bearing blocks, anti rotation bracket and blade grips!

I went to the field yesterday and gave the engine a quick test run which all went well see the video attached. I do have 2 issues to resolve being that i need to find a fuel line t-piece that is gas resistant which is proving a little tough to find in the UK. Also i need to make a choice on what main blades to run i can go up to to 710 but not sure what to go for. what do you guys think

I'm aiming for a headspeed around 2000rpm and running a 40:1 fuel mix with amsoil sabre and normal pump unleaded. I should get around a 9 min flight if I've done my maths correctly.

any way ill put up some more info again when the build is done!

https://www.youtube.com/watch?v=vHcnGRrbnrk

[trillian]

Looking good! Depending on your flying style, you may find you don't need as much as 2000 rpm. I played around with a few different headspeeds and finally arrived at 1800 on my Raptor. I setup my idle-2 at 1900 but never need it.

Blades are one of those things where it's personal preference combined with the heli airframe and headspeed etc. I've had all good experiences with Radix and Rotortech 710s, Edge 713s and most NHPs. SABs have been mostly good but I had a pair of 690s that were terrible on my gasser but had worked well on someone's electric Raptor I have SAB 730s now and also liked some older 710s.

Regarding the T fitting, I'm using a metal one, (originally for nitro) that I've had for ages. I'll see if I can spot something similar out there.

[trillian]

I have something kinda like this for easy fueling (they also have this in blue). https://www.sussex-model-centre.co.u...-filterredgold

[trillian]

I would have thought plastic with a metal mesh would be ok as well.

Yeah, probably lots of plastics tolerate both. I've never looked into what kind of plastic is OK for petrol vs nitro and I have occasionally used nitro fuel accessories and they did not melt.

[andypaddlerking]

hey folks

i got a couple more jobs done this evening with the help from a few folks on here.
ive ordered the correct fuel line t piece from nexus models with some helpful advice on the phone.
ive soldered on the new rcproplus d4 battery connectors to the power lead and rx packs which are awesome by the way!
and finally tidied up all the wiring a bit.

The tracking on the remaining parts is looking hopeful to come in some time next week all being well.