Hard top. I hope you are not talking to me because I have nothing bad to say about the engine I just had a problem with a muffler weld crack. Anyways I geuss there email wasnt working so I got a response today and they are sending me a free muffler!!! This is the service that takes engine companies to the top. No if they keep up the quick responses they will be great!!!!

Originally Posted by Extra260

Hard top. I hope you are not talking to me because I have nothing bad to say about the engine I just had a problem with a muffler weld crack. Anyways I geuss there email wasnt working so I got a response today and they are sending me a free muffler!!! This is the service that takes engine companies to the top. No if they keep up the quick responses they will be great!!!!

lol no 260....what i said was directed to those who shoot their mouth off when they have nothing to complain about. yes i have had 2 mufflers crack now.....and it all seems to point to the fact that the material used is too thin for the intended job.

i have made my own muffler now and i will post some pix of it here soon. it doesnt look pretty but its functional.

but as i have said...this is a great little engine once all the bugs have been sorted.

cheers
craig

here are some pix of the muffler i have made for my model.
its a bit better than the original....and it works

cheers
craig

Hi All

The Chinese New Year's shall arrive soon, pressing conventionally, in China, people have a 15 days holiday during the Chinese New Year. After the holiday , we will release our new GF26I toward the market.

We would like to test and receive have experienced feedback from experienced gas pilots. If you have 3 years or more of gas engine experience in the RC aircraft industry, you could qualify to receive 1 of 5 free test engines.
There is an application that must be completed and an agreement that needs to be signed after the pilots are selected. Please email to service@crrcpro.cn and service@westernhobbies.com for more details and the application.

Thanks !

CRRCpro Group China
Westernhobbies & CRRCproUSA

Done.

Wow, I had another muffler crack today!!!! They really need to consider looking at there welds.

extra260.....

it isnt the welds that crack. its because of the very thin material used. i have addressed this problem several times across several different online forums.

can i ask you WHERE it has cracked??....at the engine end or at the outlet end?? if its at the outlet end then its vibration related. both my mufflers have broken off one outlet pipe and on the same side. as you can see in a previous post that ive tried to remove the vibration effect from the muffler by mounting it to the airframe. this is still a "works in progress" as i continue testing of this idea.

a suggestion for you is to re-tune the engine as this engine will vibrate if its off tune even slightly. make sure you have the correct timing set and that you have no gasket leaks anywhere. if you have the plastic type intake manifold....turf it in the bin and get a stainless steel one as these dont warp from the heat of the engine and leak.

cheers
craig

Yeah I think it was vibration. I think I have it tuned well. On an upline the engine dies down if I make it any leaner. I have it set to a 50-1 oil ratio. Is this right. Each flight the engine has more power.

Originally Posted by Extra260

Yeah I think it was vibration. I think I have it tuned well. On an upline the engine dies down if I make it any leaner. I have it set to a 50-1 oil ratio. Is this right. Each flight the engine has more power.

if it dies on an upline then you have it too lean. turn your high speed needle out 1/16 of a turn. i would suggest you change your fuel/oil ratio to 40:1. are you using mineral or synthetic based oil?? and what fuel are you using??. what size and make of prop are you using?? what top end revs are you getting??

cheers
craig

just an update on my new design muffler.

ive now done 4 flights with this muffler and other than 2 bolts coming loose in-flight it works great!!. the smoke system still works as it should and im thinking of a second heater coil around the header pipe as this part is the hottest when the engine is at full noise.


i was talking to a guy who works with performance engines the other week. we got talking about engines and running alcohol fuel. we discussed this particular engine and what mods would be needed to run methanol and make some serious horsepower. it was agreed that uping compression was a good start. when i got home i took the plug adaptor out and had a look inside the cylinder to see how much more squeeze i could get....guess what......cant get anymore as the piston is just about touching the head.

and here is the fun bit. my idea (borrowing in part from someone else) is to machine a relief into the piston crown and remove 20 thou' from the base of the cylinder. this will have a 2 fold effect. 1. it will raise compression suitable for methanol. 2. it will lower/raise the exhaust and transfer ports respectively thus advancing port timing. this theory will be tried on another engine i have here(its a ryobi 23cc) before i try it on my gf45 engine.

cheers
craig

Sorry I didnt respond. I knew it was the tuning. It was actually one of the ingition wires broke. I thought it dies funny. I re sodered it and everything works fine. On the upline it sputtered and stopped without warning.

Originally Posted by hardtop351

i was talking to a guy who works with performance engines the other week. we got talking about engines and running alcohol fuel. we discussed this particular engine and what mods would be needed to run methanol and make some serious horsepower. it was agreed that uping compression was a good start.

I seem to recall suggesting this on another set of forums some time back :-)

and here is the fun bit. my idea (borrowing in part from someone else) is to machine a relief into the piston crown and remove 20 thou' from the base of the cylinder. this will have a 2 fold effect. 1. it will raise compression suitable for methanol. 2. it will lower/raise the exhaust and transfer ports respectively thus advancing port timing. this theory will be tried on another engine i have here(its a ryobi 23cc) before i try it on my gf45 engine.

A possible fly in the ointment might be the fact that the bore/head is hard-chromed and that by boring the top you may compromise the integrity of that plating at the interface..

What's more, by boring the top of the cylinder as you describe, you will be changing the parameters (angle/area/width) of the squish-band -- which can have a significant (possibly detrimental) effect on the engine's operation.

While it's fun to play with a low-cost engine like this to try and get more power or convert it to an alternative fuel, it's sometimes a risky business and is rarely a good substitute for just laying out a little extra cash to buy something that's just plain better "out of the box".

But go for it -- and report back how you get on.

Originally Posted by XJet

I seem to recall suggesting this on another set of forums some time back :-)


A possible fly in the ointment might be the fact that the bore/head is hard-chromed and that by boring the top you may compromise the integrity of that plating at the interface..

What's more, by boring the top of the cylinder as you describe, you will be changing the parameters (angle/area/width) of the squish-band -- which can have a significant (possibly detrimental) effect on the engine's operation.

While it's fun to play with a low-cost engine like this to try and get more power or convert it to an alternative fuel, it's sometimes a risky business and is rarely a good substitute for just laying out a little extra cash to buy something that's just plain better "out of the box".

But go for it -- and report back how you get on.

im not touching the cylinder xjet....im gunna play with the piston crown and machine it flatter(as the piston is slightly domed) to allow the piston to further up the bore and raise compression.

yes i recall a comment made about compression etc in another forum too lol.

cheers
craig

I've been using my GF45i on a GreatPlanes Giant Stick. I have more than enough power to hall this heavy plane as far vert as you want to go plus hover . I have had some problems with the transition, but it will idle all day and hasn't quit on the down side yet. You get what you pay for and it isn't a DA.

Originally Posted by hardtop351

im not touching the cylinder xjet....im gunna play with the piston crown and machine it flatter(as the piston is slightly domed) to allow the piston to further up the bore and raise compression.

There's not a lot of meat in the top of that piston -- and flattening it will still alter the squish-band parameters so I'll be really keen to see how you get on.

Also remember that you'll be lightening the piston so the finely tuned machine that is a CRRCPro GF45I may shake a little more after your surgery :-)

Right now I'm evaluating the DL50, an engine which isn't much more expensive ($370 shipped) but is looking a *lot* more capable.