CRRC Pro GF26I

[hardtop351]

hi guys. i have one of these engines also. it is 1 of the original batch sent out for testing and evaluation.

i have been away from modelling for a while due to family and work commitments.....but i still have the engine....still on the stand.....and still awaiting for me to do something with it!!!!!!

anyways........

i have read the last few posts about this engine here and i would like to offer my suggestions.(yes rcign....SUGGESTIONS!!!! lmao)

i am guessing by the reference to "the hub" it means the gold coloured adaptor that the prop bolts to??..yes it is made of an alloy type material and yes it will fail if not properly attached to the engine crankshaft. i would imagine that if it failed at top speed the prop would propel itself forwards a short distance.

RCIGN is correct in saying that the keyway is for location only....it is the taper which drives the adaptor. the keyway is also there from a safety point of view in that IF the adaptor becomes loose on the taper it will move and shear the key and stop the engine.

i also have a friend who owns a machine shop and i would personally machine a new adaptor from a more suitable material. steel does come to mind but it would make any model the engine was installed into nose heavy. perhaps a more tensile grade of alloy...although you don't want the same thing happening again.

cheers

[joseae]

I replaced mine and have since run the engine for about one hour and so far (KOW) no signs of cracking. I followed the directions given by a guy from Spain who services CRRC engines in his country. He says it has more to do with how much torque you use when installing the hub and making sure the key is in the right position, meaning when you slide in the new hub it should go in smoothly all the way, if it doesn't, the key is misaligned. And you should not apply more than 10 lbs. of torque. Also try to avoid overtightening the prop nut. I now use a short wrench to ensure I don't go too far.

[hardtop351]

i did read somwhere in this forum that someone said something about the hub being out of round....it wobbles when you turn the engine in other words.

mine also does this.

my engine is still sitting on my engine test stand...has been for ages now. mainly due to the fact that the intake manifold is warped and as a result of this it has pulled a thread in the plastic material. i will be machining one up from alloy soon and then will get back to running this little engine to break it in.

i also read about radio interferrence from the CDI unit. i have had this problem also with my crrc gf45i engine. my solution was to modify the engine to run a standard 4 stroke glow plug and methanol fuel......but that is another story in itself.

it doesn't matter if you use FM, PCM or 2.4......if the signal coming from the module is strong enough it will cut through your reciever no matter what modulation you use. i have already lost 1 airframe due to this.

hope this helps
cheers

[Noddy]

	Quote: Originally Posted by hardtop351
	i also read about radio interferrence from the CDI unit. i have had this problem also with my crrc gf45i engine. my solution was to modify the engine to run a standard 4 stroke glow plug and methanol fuel......but that is another story in itself. it doesn't matter if you use FM, PCM or 2.4......if the signal coming from the module is strong enough it will cut through your reciever no matter what modulation you use. i have already lost 1 airframe due to this. hope this helps cheers

Your first solution to the interference problem seems a little extreme, doesn't that take away the point of using petrol for economy , but as you say that's another story for another time.

I have posted about interference myself. I was using PCM and had horrendous problems in as much that all was well with the engine off but as soon as I started it the control surfaces went whappy. My final solution was to switch to 2.4 gig Spektrum and what do you know, 100% reliability. Since the swap over I have not had so much as a twitch, all my problems have vanished. Could it be that the RF noise from the CDI isn't strong enough to swamp the 2.4 signal ?

[zool.on]

Hi,

I got my new hub from Ray today. There was some talk about a new redesign of the hub. I did not ask Ray if this was a new one or not but it is a little different. Here are some pics.

The new on is on the left in the side by side and on the bottom engine pic.

[ken crane]

	Quote: Originally Posted by zool.on
	Hi, I got my new hub from Ray today. There was some talk about a new redesign of the hub. I did not ask Ray if this was a new one or not but it is a little different. Here are some pics. The new on is on the left in the side by side and on the bottom engine pic.

it is has a small design change. i got one yesterday. out of the 7 26s i bought only 1 was split. i have not had one split only the one that came like this. ray was awsome as always.

[hardtop351]

i was talking to a machinist mate of mine and he believes the spliting problem is related to the composition of the material used. it seems that some grades of alloy are not "annodising compatable"

annodising is the process of surface hardening as well as imparting a nice colour to the alloy. annodising is a hot process and so would cause the dramas of splitting as it can weaken the material.

alodising is a similar process although it doesn't case harden the material. it is also a cold process. alodising will also impart a gold colour on the material protecting it from corrosion.

as for the ignition interferrence.......

it doesn't matter what radio gear frequency you use....if the interferring radio signal from the CDI unit is powerful enough it WILL cut through your radio gear. i'm sure we have all been in the car listening to the radio when it starts making those funny "i'm getting a phone call on my mobile" sounds. a typical mobile phone uses a frequency at around 850 to 900 mhz. an average car radio is down around 88 to 108 mhz. yet it is powerful enough in signal strength to interfere with anything close to it.

yes i know my cure to radio dramas could be considered a little extreme.......but it has worked for me. as for fuel consumption......i don't really care....i'm more worried about getting my plane into the air and enjoying it after spending thousands to get it airworthy in the first place. i empty the 16oz fuel tank in my plane in about 15 mins.....at full noise the whole flight.

......and the 14oz tank of smoke fluid in about 10 mins!!!!!!!

cheers
craig

[rcign]

They fixed one of the problems, the key slot is much shorter....Cast aluminum is not for hubs, anodize or not...The hub should be 6061 or 2024 extruded bar stock...Not expensive, there is no reason to use a cast hub...
If the hub is perfect and the crank is twisted, it will still wobble...There is only 1 bearing on the front of the crank, any twist will be maginified at the end of the hub...
A stripped carb insulator can be fixed at least once by running a #21 drill all the way through and tapping the holes for a 10-32 or 5mm .8 bolt...Don't let the bolt go too far through the insulator, if it contacts the cylinder it will force the block away and strip the new threads....

[joseae]

I am having problems starting my engine again. After 7 or 8 consecutive good runs it just started backfiring and became almost impossible to start. I also found the idle has become unstable. I will try to tune up the carb tomorrow and change the spark plug if indeed it is fouled.

[zool.on]

Hi Joseae,

Start with the plug and maybe take a look at the ignition / timing. If the engine was running ok for 8 runs there should be no need to adjust the carb. I had a problem much like you are talking about with a other brand engine and I chased the needles for a day and in the end it was the plug.

[2robinhood]

Also check or change the ignition battery.

[edwal07]

Make sure and keep your battery up, I had problems with the ignition and I put a 6v pack with a regulator and have not had a problem since.