Snorbitz

It was just a thought as i've got access to these at work. Never mind.Edited By Shuglu on 13/07/2010 14:43:37 Edited By Shuglu on 13/07/2010 14:44:53

Has anyone ever used these for engine mounts. AV MOUNTS ?

Do you really think a pitts muffler would reduce the noise?. There's nothing at all in the can section of the exhaust that it comes with it so its not surprising its so noisy.

So back to the running-in. I ran the engine for 20ish minutes at around 3000rpm....thats about 1/3 throttle on the TX which is about right. Then turned off and let it cool down naturally. Then after wiping the black spots of oil/soot off my neighbours garage door and my ankles which i hadn't noticed before started it up again by hand. I think the 25.1 mix has something to do with the spots of mess (i must add its nothing compared to a glow engine's goopy splodge). Even after just one heat cycle the engine is a lot smoother with a reduction in vibration and maybe its just a bit quieter... its still way more than a glow but getting better. You can tell just from the way the fuel is jiggling about in the tank. So i repeat the process for run No2, Starting after just a couple of flips and taking it up to 3500 for 25/30 minutes. Its barely used just over half a tank after 45mins which is around 230ish mls,  which ok is unloaded and low revs but i'm very excited at the prospect of the fuel savings to come. It will have paid for itself in no time.....thats what i'm telling SWMBO and to be honest i think i'm right.Run No3 went ok an i have to admit i did blip the throttle a couple of times before i turned it off. Anyone who says they don't is lying!!!. I'll be honest with you....its awesome....it sounds very powerfull and really wants to rev....there is no lag in throttle response whatsoever. I would say its comparable to the F1 engines i work with for response and thats saying something!!. The noise will quite literally shake your fillings and your neighbours will hate you while you run it in but hey they should turn there telly up. I admit to having a little tingle of excitement down my spine to think i'll be flying it soon. I've stopped at 3 runs for now as i've ordered an 18" prop to replace the 16" i've got on it at the moment. Then i'll continue with the running in. So far i'm very happy with the whole package. Its used around 600mls of fuel and hasn't missed a beat. Fingers crossed its a good omen!. The noise factor may be an issue to think about but i won't do a noise meter check until its fully run with an 18" prop and is in the plane. I'll stay with the supplied silencer too until i know for sure what the final Db reading is. Edited By David Ashby - RCME Administrator on 13/07/2010 12:14:16

You're rite in your observation GONZO it is very close to the mounting block. On the test bed i used the nylon engine mounts that came with the model and there's at least an inch between the carb inlet and the wooden mount. The block of wood you can see in the earlier photos is what i will be using in the plane has a carb size hole in it already but i will need to open it out just a little as there will be fuel lines passing through there and maybe some electrical wiring too.

The choke is a single butterfly operated via the lever on the outside of the carb and latches open or closed using what feels like a d-tent (spelling?) spring or similar. I don't think its effected by throttle position and after you've started it it just sits in the open position.

The First Run: Well i mixed up a 25.1 oil/petrol mix and filled the tank full. Charged all the batteries and made sure the isolator was working. A light tells you when its active which is very handy i find. Just went over the engine to make sure all the bolts were tight and the linkages were ok and following the starting procedure went for the first fire up. Closing the choke flap(manually) with the ignition off i turned the engine over by hand to draw the fuel up to the engine. I've used a full length piece of tygon of around 750mm so it took quite a lot of turns but it did draw it all the way up eventually. I then opened the choke flap fully and turned on the ignition and with my leather gardening glove on spun it over.....and again....and again. Nothing!!. I felt i wasn't spinning hard enough so i got the electric starter out. It then fired straight up. I think it just needed a good squirt of fuel into the carb by the pump which i couldn't manage on my own. Its quite a shock to hear it run for the first time. having being used to glow engines no bigger than 9cc a 26cc petrol is quite a change and this engine sounds like a completely different animal. Its very loud....maybe too loud for some i fear but it ran quite well to start with all be it a bit lumpy. It never cut out and after a few minutes i took the revs upto about 2500 and then 3000 and as it warmed up it really settled down. There is no doubt that vibration is a factor i will have to deal with when it comes to instaltion ibn the airframe but i'll cross that bridge when iget to it. After about 10 minutes running i stopped it via the TX and did a quick inspection for leaks etc. Then fired it back up...this time by hand. It more or less fired first time and the way i would describe it is like hand starting a petrol flymo. I am acutely aware that this engine is very powerfull and its not something you'd want rapping you over the back of the knuckles so i may opt for the electric starter when its finally in the plane itself.Edited By Shuglu on 13/07/2010 10:32:30

If anyone's got any questions on what they've seen so far please put your hands up. Likewise if you want anything photographing that you can't see or dimensional info just let me know.

Ok so i've mounted the engine onto the test bed and connected all the fuel lines and electronics. I've tried to isolate the tank and the electronics as much as i can from the vibration as i'm expecting quite a lot initially. Here it the set up. The fuel tank is sitting on some foam and the CDI unit is soft velcro'd to the table. I've used a throttle servo as i don't see the need to be messing with the levers so close to the prop if i don't need to.....it'll give me an idea how responsive it is to servo inputs too.The rest of the switches/batteries/reciever and opto isolator are sat in the grey box which is also sat on a rubber mat.

This is my routing for the manual choke lever. I think using a servo to operate it is just excesive and anyway i don't have enough channels available on my reciever for anything else. I'll support it from the 2 engine mounts with some home made aluminium brackets. It only needs operating prior to starting then it sits doing nothing.Edited By Shuglu on 13/07/2010 09:11:44

This shows you how close things are going to be. I've had to put some countersunk holes in the wood block to accomodate the carb fixing screws. I'll have to make a cut out for the choke lever too. Its shown here in its normal running position but when closed it clashes with the block.

Yes its the latest version of the 26cc engine CRRC make. Max power has gone up from 2.4 to 3.15ps and hence the prop size required has increased too. (I've got a 16x10 for sale if anyone is interested!). I think i'll go for an 18x8 to start with but i'd like to go to 3 blades eventually once i'm happy everything is well bedded in. I've got my 2 stroke mineral oil for the running in from a local autoparts shop but will be going over to a fully synthetic once the first few gentle flights are out the way. Probably  BelRay H1R.

The prop is one thing i have to change actually as i bought a 16x8 to go with the V2 crrc engine but i think it'll be ok to start running it in on, then swap to an 18" as is required. The rear mounted carb version of this engine has nearly a 1/3 more horses than the side carb version and hence requires a bigger prop. I'll bare your comments in mind though Gonzo when i come to finally mount it in the plane. Cheers.

The block of wood in the previous post is the spacer that you get with CMP Zero to adjust the final prop position and i've worked out that the block plus engine brings me to where i need to be to clear the cowl with the prop. It comes with a hole already in it and luckily its just where the choke flap sticks out. It means that i'll have to route the fuel lines somewhere else though.Initial impressions of the engine are its nicely built with no nasty rough edges and all the parts look like quality items. I like the addition of a spark plug spanner and correct size allen key for fitting the exhaust/mounting bolts. So far so good. The test bench is all ready now to fit it to so i can start the "running in" procedure.

I've spotted my first potential problem in that the choke butterfly which needs to be close for priming of the engine sticks out beyond the engine mount...ie into the firewall area. I think you'll see what i mean from the photo. I've also noticed that the choke and carb levers are very close together. That's going to be a little challege connecting them all up.  

Heavy duty on/off Switches and opto isolator switch from Just Engines also arrived. I like the fact that this opto switch comes with an "ON" LED to tell you when the ignition is live.

I've now recieved my engine and this is what you get in the box. All nicely packed and comes complete with engine mounts.