Andology
New Member
Posts: 6
Loc: Tropical island in Thaila...
Reg: 08-03-05
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 08-14-05 09:01 PM - Post#64709
My first ‘personal’ experience of a Gasser. The GSR260.
I have built & flown 30, 46/50, 60, 90 sized 2 stroke glow engine helicopters for coming up 11 years this year. I also had a piccolo EP heli as my executive toy I used to keep in my car so I could grab it out and fly in the hotel rooms & lobbies while I was away most of the week as a business executive. This GSR260 from JR is a BEAST! (and I doubt I will be flying it in any hotel lobbies! 
I have to say, I have never owned a JR machine before, or even one of their transmitters.
This kit is really nicely engineered, easily the best quality kit I have built so far. Difficult to compare really though, when I put it up next to my current workhorse (Raptor 60), it makes it look like a cheap pile of Sh*t! (Although thanks Thunger Tiger if you’re listening: I have had some really good solid flying time over the past year or so with it – one gripe, just in case you’re listening Mr TT; I had to replace the stock engine on that thing after only 2 tanks of fuel. When I pulled it open to see what all the cutting out was about, it became apparent that one of your underpaid Asian women in whatever sweat-factory you’re currently using managed to bolt the engine head on without first checking that the head shim was square in place and so there were fragments of shim all over the crank / conrod and the piston/liner was scored beyond repair. Thanks. – gripe out.)
Anyway, here are my notes on building the GSR. I have not owned a Gasser b4 so please look out for anything that doesn’t look right in any of the photos, I have popped a few questions along with some of the images so anyone with any GSR experience I would appreciate your views / input / advice.
This is the bit where my wife screeches “WHAT THE F**K IS THAT!?
Then I silently count 4 seconds in my head anticipating the next question “HOW MUCH DID IT COST?” – this is where I start to explain the once in a lifetime deal I got that I just couldn’t say no to… you know the drill – after all, it was too big to hide from her and blend it in with all my other stuff
The box is pretty big. That top box that the kitten is on just holds the boom (CF). The box under that holds the nose & tail Canopies.
laying the fuz pieces out gets me excited already!! Note R60 & incomplete Patriot 40 wing for size ratio guide.
11pm
aaaahhhhh… all set, cup of tea, tools at the ready, nice clean work surface (it took around 2 anxious hours to clean the table top of all the Patriot 40 plane pin board and specific tools before I could even start the GSR.) I like to keep a couple of small plastic boxes on my work area and put all bag contents into them as I go through the manual. I like the bag labelling system JR use, not all kit manufacturers do that, nice when they do.
Bottom left shows the two manuals you need to continually cross-reference. There is also an “errors sheet” (3 very minor things). I highlighted the relevant pages that had an error first while reading through front to back before opening any bags (good practice). One of the manuals is the old GS Voyager version as it is currently the closest they have to the GSR construction manual in English. The Manual for the GSR260 is all in Japanese and if like me your Japanese is “rusty” you need to keep switching from one to the other… I would say that for the sake of paying a translator a few hundred bucks to write an English version would be well worth JR’s investment since I believe the building takes a considerable amount more time than it need to (and @ $1900 you would think they could splash out a little . Most sections in each version of the manual are very similar if not the same on a few pages but obviously it is the things that are NOT the same that are important. There isn’t really anyway to work out what is going on in a few Japanese sections that are not covered by the GS English manual. So far, that is the most avoidably stupid thing about the kit.
Reminds me of back in the day when I used to race RC cars. The Schumacher buggy manual used to all be in Japenese too, think it was the Schumacher one, can’t remember.
6 hours into the build.
Main frames and upper frame unit completed. Bit of a balancing act when lining up bolt holes between lower frames and upper frames The holes lined up perfectly with all spacers, just need 3 hands to hold upper frame in place over lower and hold hex spacer in place and thread the bolt through all at the same time.
FYI – when I called my wife in to help hold the upper frames for me, I got her to make me more tea, you may have noticed in this picture my tea has already been filled and emptied about 8 times by this point.
I started building this at exactly 11pm so this picture would be at around 5am.
12 Hours into the build and all the main bits and pieces are completed. Servos are in, skids are on (those skid clamps are a tight old fit!!). The tail is pretty much done at this point, just need to start trial fitting the tail fuz around the tail control rod clamps.
Engine is in (roughly).
Still need to make all the ball link rods up but my hands and fingers are raw to the bone already getting that lot together, just can’t take the pain!.. Gonna have some kip and hope my fingers are back into action tomorrow night.
Very nearly finished now. Look at this junk!
The second I saw this thing through the unopened bag I instantly tossed it back on the floor and muttered “yeah… right… as if…”
Any educated opinions on good quiet pipes? Would rather it be quiet than HP as this is my replacement Commercial Cam Ship so need to keep the noise levels as low as poss. Suggestions and maybe links to products would be massively appreciated.
is this correct? And the same thing with the other vent on the carb yeah?. From what I can work out from the instructions, there is no pressure feed from exhaust to tank yeah? Currently I have the top nipple on tank as picture and the one on the carb the same at the front – please let me know if this is incorrect.
I found I needed a washer to adjust the angle of the engine very slightly to achieve a perfect alignment between engine and clutch bell whilst maintaining good gear mesh etc.
here you can see where I have crimped the tail control link. I don’t have much confidence in this type of connector; I have had a bad experience with one before on a different model. I used 30 min epoxy after sanding (to roughing up only) with 150 grade sand paper. Then I used a pair of pliers and gently crimped the connector in several places. I am hoping this will give me a little more security – I have done this both ends (because the air cannot escape when you insert the CF rod into the threaded connector, they keep wanting to pop back out b4 the epoxy sets, I crimped them slightly first to let air out). Please let me know if any of you have had bad experiences with this type of linkage failing.
BTW- the rizla papers in between the gears was from setting up the mesh. Normally 4 layers of the blue type rizla makes a perfect mesh IMHO
Also – note use of S9253 servo on throttle as well as tail, you think this will be ok? I used this servo on my Rappy 60 with a Throttle Jocky pro with the Optical upgrade, thought it would be good to have the throttle slightly ahead of pitch speed to reduce load lag (although with a 26cc engine I am not expecting much load lag )
I chose to epoxy some HD foam as shown as the fuz was very slightly touching the side of the lower frames. I could tell it was going to make an awful noise even with the smallest amount of vibration. The fix worked perfectly both sides and feels rock solid with no “rattles” etc.
I like the tail on this thing. There is very little slop in the linkage. Loads of messing around re-shaping the tail control rod clamps on the tail boom so that they clear the boom-fuz and tail supports & still slide freely.
I have only had a couple of belt driven tailed Helicopters. The majority of machines I have had in the past have been shaft drive. Despite little time with belts vs shafts, I think the belt drive is much smoother, and in some cases quieter when compared to shaft/bevel gear drive sytems. Blade grip holders are kinda plastic/GRP/CRP type material, at first I thought they were anodised CNC Ali, they look like machined Ali.
Is it right both those rubber ‘o’rings go together or one each side of tail pitch slider? It wasn’t clear on the Jap section.
Can anyone recommend a good pair of CF tail blades for the GSR260?
This is where I am planning to mount my 401. I have a 601 but have decided I want to keep the electronics as simple as poss. I also heard that the 601’s don’t like gassers. Please let me know if that is nonsense I have picked up or whether there is anything behind that rumour. Are electronics more sensitive around gassers vs glow? I imagine the coil is simply an inverter as usual so does it interfere with things like gyros/ receivers etc?
Please share your thoughts on the gyro placement and if you know of any probs using the 401’s or 601’s with gassers.
Just about 100% metal head. (not quite though)
Interestingly enough, I have never flown a CCPM chap before. I was really looking forward to this being my first. CCPM just kinda makes more sense to me. It looks like a far more linear based movement compared to the standard 4 point swash. I love this stuff man, just totally slopless, just cant wait to see how it feels in the air, I reckon its gonna hover like its sitting on the table… I wanna eat it! I can often just stare at the marvel of engineering like this for hours. It sends me off thinking about “some chap” who sat down and worked out the whole cyclic control system for the first time. Having started early life as an electronic and mechanical engineer I appreciate stuff like that 
The head comes already assembled so I reassembled it re-threadlocking etc as I don’t like trusting factories with stuff like that (like the cardinal rule when passing a firearm to someone and they stupidly ‘ask’ if it is loaded. If you need to ask, you need to check).
The main shaft was a smaller diameter than I had expected. It actually looks to be the same dia as the Raptor 60 shaft. I think the GSR shaft is solid vs the hollow raptor shaft though. (don’t quote me on that )
So this is the 99% completed beast in her nakedness. The canopy went on beautifully. I drilled the holes exactly where they were marked on the gel coated surface and the holes lined up perfectly – I love it when that happens!
Canopy window was cut reasonably well from factory to fit recess in main canopy mould, a few trims but generally all pretty good stuff.
I spent an awful amount of time getting the horizontal fins right. I am a little too much of a perfectionist with these kind of things and can often spend hours on something most would just say “that’ll do”. I am around 94% confident the H fins will stay where they are. I used 30 min epoxy after using 80 grit paper to roughen both contact surfaces.
All in all, so far I think this Kit ROCKS!. It is the best machine I have built to date. I think I will feel very confident mounting my Cam gear on this. I like a helicopter that inspires confidence in its reliability during the build. I have built many a model before be it cars, planes or helicopters and sometimes i get put off while building it if the kit seems to be low quality. A good building experience where all the parts are there, all the parts fit and none of the parts look like they should be re-designed can really help me concentrate on the flying experience at the field rather than constantly looking for the “next thing about to break or fail”.
I don’t think I will go back to 2 stroke glow for helicopters if this one proves it can serve my purpose. The benefits of gas over glow seem to out weigh quite a lot, the cost of the fuel alone looks to have potential to pay for itself already before anything else..
Just gonna finish the gfx off and I will post more pics again. Please ask me any questions you want about the building of this kit if you are planning on taking the plunge and getting one yourself.
If you have already built / flown one of these please help me as best you can, thanks.
The stock Airfilter HAS to go along with that crappy pipe. Any ideas on where I get one of those K&N jobs? And how do they mount? Do I retain that plastic housing with the choke arm with the K&N or is it a different mount altogether? Some light shed on this would be great (or any links to other posts covering this, my initial searches came up blank.)
I will be using the following unless you guys say otherwise:
S9252’s on CCPM
S9253’s on Tail & Throttle
Futaba 401 Gyro (or 601 depending on recommendation – will use whatever is safest)
Heavy duty switch
Biggest RX battery I can find
Anyone remove their pull start and use shaft start instead?
My pan/tilt system will need to use the space where the pull start is. My tests so far show that I will need to upgrade my 12v starter to a high torque one; I get around 0.75 rpm using my standard hobby starter (and the wires get V.Hot)
Got more questions coming up soon so I hope there are some GSR or other Gasser owners out there that can help me out with my first Gasser. I will try and return your help as much as I can if you include a link to one of your posts for me to look at in return.
Thanks fellow members.
Andy
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Steve Walker
Senior Member
Posts: 397
Loc: Cincinnati, Ohio USA
Reg: 07-24-01
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08-14-05 09:21 PM - Post#64710
In response to Andology
Boy, I'll bet the guys on dial-up are gonna be cussing!
- Steve
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Andology
New Member
Posts: 6
Loc: Tropical island in Thaila...
Reg: 08-03-05
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08-14-05 09:44 PM - Post#64711
In response to Steve Walker
I bet you they are not "cussing" for two reasons:
1) I am using dial-up and don't feel the need to cuss anyone.
2) Members with bandwidth issues will have turned off forum images in their display preferences anyway.
Thank you for your input.
Andy
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Rudy
Full Time Senior Member
Posts: 4830
Loc: Houston, TX USA
Reg: 03-14-00
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08-15-05 12:35 AM - Post#64721
In response to Andology
I like the photos and the write up is great.
Im building a Century Predator Gasser my self.
The JR Gasser are mainly just used for camera work here in the US. It Looks like that what you plan to use it for as well.
Is the cat going to be the test pilot 
If Wile E. Coyote had enough money to buy
all that ACME crap,
why didn't he just buy dinner? |
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Andology
New Member
Posts: 6
Loc: Tropical island in Thaila...
Reg: 08-03-05
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08-15-05 11:17 AM - Post#64732
In response to Rudy
lol, my calculations show that the kitten should easily be lifted by this thing!..
You're right, this will be my new camera ship. I like the raised skids as stock, it has increased my options for gimble testing massivly.
How you finding the Predator Gasser? i had a Century helicopter before, the hawk 30, i upgraded it to the falcon (46 conversion)- that was my first heli, i learnt just about everything on that, fond memories. The reliablity was really bad but that was like 10 years ago now so i bet the Predator is totally different.
Thanks for your comments, what radio etc you gonna use? what is the engine that comes with the Predator?
Cheers
And
This was my first heli - Century Hawk. Learnt how to crash with this model, many times over
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Anonymous
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08-16-05 01:04 AM - Post#64757
In response to Andology
Quote:
From what I can work out from the instructions, there is no pressure feed from exhaust to tank yeah?
That's correct. DO NOT put a pressure feed on the muffler, unless you want to turn your helicopter in to a flame thrower!  The carburetor on your G26 has a pump in it, so there's no need for a pressure tap like there would be on a nitro machine.
As for mufflers, there's not much in the way of options out there. You're pretty much stuck with either the Hatori gas muffler (around $220), the Century V.2 Torpedo ($125), or the JR gas muffler (no idea what it costs). I'm using the Century Torpedo on my Bergen Intrepid Gas EB, but I just installed it this last weekend and haven't had a chance to fly it yet, so I can't give you a firsthand impression yet. Supposedly, it's around 80 dB at 3 meters, but we'll see about that. I used to be running the stock canister, though, and you're right... it's a turd, albeit not as bad a one as you might think.
A word to the wise: Gas engines do not tune like a nitro engine. You will find that gas engines (the G26 especially) will emit much more vibration if you don't have them tuned correctly. That was the first obstacle I encountered when tuning my engine in - it can sometimes be difficult to distinguish between vibration from engine tuning and vibration from poor build or mechanical imbalance. I was fortunate to have an experienced gasser pilot and the factory itself to help me ensure that my machine was good, so all that was left for me was to get the engine tuned.
What worked for me was to get my low end needle so that the engine 4-strokes until the bird just begins to lift off. High speed needle is a matter of flying it and listening for the same. Like I said, though, if your mixture isn't right, you'll be causing that G26 to shake a lot more than it would otherwise. So take your time tuning (and make small adjustments at a time... like 1/16th of a turn, 'cause those needles are sensitive), and get it right, or else the machine will never run like it's supposed to.
I'm not even going to get into the whole oil conundrum (it's a mini-war in itself), but I will say that I've been using Yamalube 2-R at 5 oz. a gallon with satisfactory results.
I also run a large amount of mechanical offset in my throttle linkage, because the carb on that G26 doesn't react in a "linear" fashion. By using the offset, I was able to keep my throttle curve closer to linear. (Even still, it's something like 10, 22, 42, 50, 100!) Your results may vary.
I'm no gasser guru (I've only had mine a few months), but I'll answer what I can.
Keep us posted!
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Andology
New Member
Posts: 6
Loc: Tropical island in Thaila...
Reg: 08-03-05
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08-26-05 05:58 AM - Post#65154
In response to Buddykitchen
Thanks for your post BuddyKitchen, i didn't seem to get a mail from rotory to say someone had replied so sorry I’ve left it for a few days...
Your info RE the Vibration is great, thanks for that. I'm not quite sure what to expect really. I have heard that the Gassers run at a considerably lower RPM than the Glow engines, is this correct? In terms of the engine vibration, is this more to do with the resonant frequency of the engine acting on the airframe? I have had a few 'shakes' on some of my glow heli's before and found in some cases by just changing the RPM very slightly it goes away. It seems from what you are saying though that the engine itself is more prone to vibration that the glow engines (which isn’t surprising considering the mass of metal it is swinging around in there ) , i'll look out for these probs on my first runs. I spent around 2 hours getting the paddles & flybar on exactly in the middle and at a perfect 180 with my paddle clamps on my 10mm sheet glass worksurface (great for building ‘true’ wings too!). I am yet to balance main blades and just remembered I forgot to order that damn blade balancer from TH while I was on there… Bollo*ks… Oh well, got an excuse to make another order now.. Normally I use the old blades bolted balanced on a couple of Champaign glasses but wanted something a little more accurate for this beast.
Following on from what you were saying about the potential vibration issues with the G260, if I can feel as sure as I can that the main rotor etc is balanced to the best of my ability, it should make an engine vibration easier to detect. I wonder if one of my first upgrades in addition to the new pipe (more expensive than I thought) should be an Ali Fan for the engine to replace the plastic one? I had tremendous issues with vibration initially on my R60, I tried everything. I got a QuickUK ali fan for my O.S70 and voila! Vibration was gone… I suspected it to be either the fan or tail as it was a reasonably high frequency vibration..
Anyway, back to the gasser
I have seen many people on a few forums having many different ideas about oil/gas mixes and wouldn’t try and cover it in this post - one stupid question though; do i use 'unleaded' or 'super-unleaded' etc. gas?
I ordered a few bits and bobs from Tower Hobbies so i can get this bird test flown and 'run-in' (although running in doesn’t seem to be as necessary with these gas engines, tell me if i am wrong though). I had to order a new fuel pump as my current glow fuel pump will probably melt knowing my luck so i thought i may as well renew my whole Helicopter compliment case with all the right gear for gas. I am selling my Raptor 60 and although i will still use glow fuel once my Patriot 40 plane is finished, Gas is going to kinda take over my case/tool priority.
I ordered some "Klotz KL-100 Super Techniplate Oil" so let me know if this is the right stuff (to at least get me going).
I also ordered fueler valves / filters and some proper gasoline tubing for stock etc.
I have one of those W.S Deans Two-piece antenna on order but not sure if i should use it on this thing. I usually have a pretty healthy paranoia when it comes to this sport so i may just test it (on the ground without engine running ) and see the results, Mr RC-Cam has a great report on this subject but couldn’t really see a firm conclusion.
I noticed in your post BuddyKitchen that you give your throttle curve figures, it looks like you are using full throttle at full pitch, I was expecting the engine to only need maybe 60% throttle at max to maintain 10 degrees pitch, don’t know why, I think I read it somewhere that the G260 was a little ‘overpowered’ and therefore don’t need to use full throttle, let me know if this isn’t the case..
Thanks for your support guys.
Andy
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Andology
New Member
Posts: 6
Loc: Tropical island in Thaila...
Reg: 08-03-05
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08-26-05 01:42 PM - Post#65160
In response to Andology
Just done the HT Shielding mod curtesy of This Post.
I used double shielding from Satallite cable (put one shielding on, then another over the top to double up)
now where did i put my bag of spade connectors?.....
Andy
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Anonymous
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08-29-05 01:11 AM - Post#65260
In response to Andology
Quote:
I have heard that the Gassers run at a considerably lower RPM than the Glow engines, is this correct?
In stock format, the G26 has a usable max RPM around 11,000. My Bergen Gas EB with the same engine runs at 10,850 rpm with a 1450 rpm headspeed. It'll spin faster, but it starts vibrating pretty vigorously.
Quote:
In terms of the engine vibration, is this more to do with the resonant frequency of the engine acting on the airframe?
Not really. The problem in your case is that the G26 has an inherent balance problem. It started life at the Zenoah G23, which became the G231. When Zenoah wanted to increase the engine size, they did it the easiest way possible, which was to bore it out and put in a bigger slug. Unfortunately, they did nothing to change the counterweight. Whereas the G231 ran fairly smoothly, the G26 is not as smooth. Not that it'll destry your machine, mind you, but it's just not as smooth as it could be.
Quote:
I am yet to balance main blades and just remembered I forgot to order that damn blade balancer from TH while I was on there… Bollo*ks… Oh well, got an excuse to make another order now.. Normally I use the old blades bolted balanced on a couple of Champaign glasses but wanted something a little more accurate for this beast.
Luckily for you, blade manufacturers are getting better and better at making balanced blades right out of the box. I've used NHP 800's on my EB, and they've been perfectly balanced from the get go. I've just bolted them on and flew. 810mm V-Blades have a very good reputation as well.
Quote:
I wonder if one of my first upgrades in addition to the new pipe (more expensive than I thought) should be an Ali Fan for the engine to replace the plastic one?
Can't answer that one for you. I don't know where you would get such an item, since I'm just not that familiar with JR birds. I'm unapologetically pro-Bergen. 
Quote:
I have seen many people on a few forums having many different ideas about oil/gas mixes and wouldn’t try and cover it in this post - one stupid question though; do i use 'unleaded' or 'super-unleaded' etc. gas?
Regular old 87 octane pump gas is all you need. Using a higher grade gasoline is just going to waste your money. Some guys swear by Coleman camper fuel (less smell), but if 87 pump gas is good, I don' t see the point in spending the extra money.
Quote:
...(although running in doesn’t seem to be as necessary with these gas engines, tell me if i am wrong though).
Per Bergen's instructions, I break mine in on 6oz. oil for the first 2 gallons, then 5oz. after that. As for flying, though, just fly it as you intend to.
Quote:
I had to order a new fuel pump as my current glow fuel pump will probably melt knowing my luck
Don't use a glow fuel pump for gas. The gasoline will destroy the silicone tubing. If it's an electric pump... well, I don't need to tell you what an electrical spark will do around gas fumes. Just get a manual pump, and make sure all your tubing is made of Tygon.
Quote:
I ordered some "Klotz KL-100 Super Techniplate Oil" so let me know if this is the right stuff (to at least get me going).
I've never used it. I use Yamalube 2-R, so I can't halp you on that one.
Quote:
I have one of those W.S Deans Two-piece antenna on order but not sure if i should use it on this thing.
A base loaded antenna is recommended, to keep the antenna wire away from the ignition system
Quote:
I noticed in your post BuddyKitchen that you give your throttle curve figures, it looks like you are using full throttle at full pitch, I was expecting the engine to only need maybe 60% throttle at max to maintain 10 degrees pitch, don’t know why, I think I read it somewhere that the G260 was a little ‘overpowered’ and therefore don’t need to use full throttle, let me know if this isn’t the case..
Why would I not want to use full throttle at full pitch? 
10 degrees is about all you're going to pull with that engine/blade size. You're swinging some pretty big lumber! Remember, like I said, the curve looks strange because the carb doesn't react linearly.
Keep us posted!
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