rcfan450

http://zen.octopusrc.com//index.php?...siutj6lv1e04h3

That's where I got mine. I emailed them and made sure they sent me the right one.

irocbsa

My Feedback: (12)

Ha! Funny you mention that. I bench tested mine for the fun of it. It sparked twice and then quit. Thankfully I already had an ignition from Milton in hand. I have about 15 flights on it mounted to a Top Flite Stinson and it runs great. One thing to mention for new users is that you will have to choke it almost every start likely due to the updraft carb.

haltom

My Feedback: (1)

Well, new ignition from Octopus rc is ordered.

What about carburetor tuning.Any one that knows how to do this?

soarrich

My Feedback: (98)

1.Start the engine, set the throttle so the engine is going 3500 rpm.

2.With the engine running I turn the "L" needle in, it is always the needle that is closest to the engine, when the engine speeds up to 4000 rpm I adjust the throttle to bring it back to 3500 rpm. You keep repeating this step until your engine doesn't speed up anymore when you turn the "L" needle in.

3.Turn the "L" needle out 3/16th of a turn.

4.Open the "H" needle 2 turns out, open the throttle all the way open. Now slowly turn the "H" needle in the engine will increase in rpms. Turn the needle about 1/16 at a time, when you get no more increase in rpm the "H" is set properly.

5.Set you idle speed with your throttle trims, it's best to take the idle stop screw completely out, you should have it so the idle is correct with the trim in the middle, and the low trim kills the engine.

6.With the engine running at the idle speed that you fly at you should now be able to snap the throttle open and the engine quickly speed up. If it just dies, turn the "L" needle out 1/16th of a turn, repeat this step until is quickly speeds up. If when you snap the throttle open it stumbles then speeds up turn the "L" needle in 1/16th of a turn until it cleanly and quickly speeds up.

7.Close the hole or notch up in the choke plate, I'll post a picture of what I mean, I do it with soldiering the hole close, some use glue or a bolt.

After you modify the choke plate the way to start the engine is:
a. Close choke completely.
b. Open throttle half way.
c. Flip engine with ignition on until the engine coughs.
d. Take choke fully off.
e. Set throttle just above idle, flip until it starts, usually 3 to 5 flips.





_____________________________

haltom

My Feedback: (1)

Thank you very much soarrich!
This seems to be a good procedure and should be quite easy to follow I think.

jparia

Hello,
I contacted the seller "Octopus RC"
This person is very friendly.
I sent him a plan of my engine cowl to indicate that the engine does not go with the candles CM6.
He suggested me the adapters of spark plug CM6 to ME8 RCEXL .
He offered me to install them.
Alson I asked all the accessories RCEXL (Ignitions, Iridium spark plug, Hall Sensor Test Kit . Tachometer, Kill switch...)
And the polished mufflers.


You think this is a good choice?




The blue area is at the spark plug ME8 & CM6:




(excuse me for my english, i'm french...)

The aircraft, 2.2m (86.614in) , 3.5kg (7.7lb 11.459oz) to vaccum :

jak_kkaall

Hy, I have the XYZ 53cc twin gas engine and lately it stops in the air after aprox.1 min after takeoff with no simptoms, It has less power and I noticed that the


right cylinder has significantly less compression by feel than the left one.
Some facts about the engine:
-It is in break in period, has about 1-2 gallons through it. Break in oil Bel Ray 2T mineral 25:1.
-Proppeler 20x8 only 7000rpm. in the past Vess 21A-7200rpm.
-Spark plugs seem dark.
-reed block seems ok.
-Although the flying field is dusty filter and carb filter are clean.
-Carb settings L-1 turn out , H-1,5 turn out.
-timing 28 TDC (was at 42 from factory and almost ripped the plane with vibrations)
-fresh gas 95octane, fresh mixed with oil.
- starts easy, going on the ground well even at idle with the plane vertical.
-Had a couple of ground hitting with the props in the past if that matters.
-I've changed the plugs, still right cylinder seems to have half the compression of the left one. Compression test made by feel with prop at the same distance(half


blade) also by the hub without the prop. The right cylinder that has much less compression is harder to flip ''backwards''(clockwise) than the usual way.
- carb gaskets are wet since first day, carb head screws full of gas.
- shut down with servo choke every time if that counts.
- Now I open them to L-1,25 H-2.


Possible answers that I've read: It could have stuck rings, or it ingested something, or overheated and may be damaged as a result.
(But not badly enough, yet, to keep it from running)
but this cylinder was always the cold one as shown by the plug.


Is the compression difference a cause of the stop or in having less power or is from getting hot?


Any thoughts?

soarrich

My Feedback: (98)

"Had a couple of ground hitting with the props in the past if that matters."

Try taking both plugs out, then turn the engine over. If it still feels like you have some compression on one cylinder you have twisted the crankshaft. These twins use a built up crankshaft and don't take prop strikes well.

jak_kkaall

So I heard that they are sensitive to prop strikes. Well it feels to have the same amount of ''friction" on the entire turn. I wish i had measured the compression of each cylinder from day one. Reading some threads, une guy had a relatively new DA50 with 5 times less compression than an older one, both run great...go figure. If it's not compression one of the key factors in engine power I don't know what is. I didn't find a thread about a difference between the two cylinders compression, only one about a nitro engine 4 stroke and that is different I quess. If the forums won't be full of DA, DLE,etc, problems i would say that this is a crappy engine but seem to me that all have problems sooner or later.

soarrich

My Feedback: (98)

jak_kkaall

Do you have a picture of your air outlet. In the pictures you posted it looks like the inlets are great, but you have very little air outlet area.

jak_kkaall

Thank you for your answers! By your unmistakable avatar photo with flames behind a jet I can tell you that today and yesterday I read all day post from you at threads about low power and low compression. From what I read about these engines It seems that after run in(break in) it will develop more compression? I thought the best compression is when it's new, or that isn't compression, it's just friction because the ring/s are not settled..my oppinion. And that might explain the fact that if the right cylinder always works richer it will run in slower, so it will develop more compression later then the left one that runs hotter as Tired old man says on this forum: ''May I ask at what ratio and was the engine deliberately run rich for a break in? The reasons are too much oil and too rich carb settings will not let an engine become warm enough to execute the break in. A "cold" engine does not generate the required wear on a ring and cylinder to perform a break in. For general knowledge, an engine will not effectively atomize the fuel entering the carb and case until the engine attains roughly 90c, or 194f. Up to that point what is essentially a river of cold fuel is being poured into the engine. After 90c the fuel starts to be effectively atomized. Even then it's not as well done as it could be. The entire engine with all it's components needs to "heat soak" for the best fuel atomization and use. That takes place when the engine attains temps somewhere between 120 and 140c and the pumping action of the case and porting becomes much more effective. Above 148c the engine starts to lose performance but does not sustain any negative effects until past roughly 170c. There are exceptions to those numbers but those exceptions are not applicable to small gasoline fueled air cooled engines. Can't go any farther with that...

So an engine needs to be heat cycled though it's normal operating temperature range for a break in. Warm up, cool down, and repeat for several gallons of gas. A few hours really. That's where some that do bench running make some big mistakes, while others that go out and fly hard 3d with a brand new engine make even more. Normal flying with carb mixtures suitable for the best performance are what wioll break in an engine faster and more effectively than any other method.''

Can that be the answer to different cylinder compression? One running hotter(leaner) than the other?
Why didn't I ever get more than 7000 rpm with a 20x8 prop and others got 8100rpm? When new I found something strange, after reading hundred of pages about walbro carb settings and break in, i realised that the start is with 1,5 to 2 turns out both needles or 1,5 L and 2 turns on H. Well after leaning the H only to about 1,9 turns out, it started to lose rpm as this seting was the leanest it could go at the beginning of it's running time? Is that normal? Another thing. i found that in order to get it smoother I dropped the timing to about 22*, and now moved it to 28*. Could that had something to do with it stopping after take of.. it pisses me off that on the ground it works all day long

jak_kkaall

If only I could make it not to stop in the air anymore. Last time I was lucky dead stick landing the heavy plane, next time who knows. And this plane means a lot to me.

soarrich

My Feedback: (98)

jak_kkaall
You have an unusual problem. This is how I would go about trying to figure out what is causing you problem:

1. I would switch to just about any other oil than Bel-Ray, it's great oil, but it's the only two stroke oil that doesn't burn in the engine. I really can't read the plugs with the Blu-Ray, with the other oils when you have the fuel/air mix correct the plugs will be a powdery milk chocolate in appearance. Your plugs are very wet oily looking, if you stick with Bel-Ray I would mix it about 50:1, I think at 25:1 your engine will take for ever to break in, maybe never. I run my engines on Pennzoil air-cooled at 32:1 all the time, it's just easier than having two mixes. I used to breaking on 32:1 then switch to 40:1 for a cleaner plane, some guys think you get more power going to less oil, but 20:1 will give you the most power.

2. I would try flying it with the cowl off, to see if it's a heat issue.

3. If you're not using 4.8v I would switch to that, 6v will just make your ignition run hot. Make sure you don't wrap your ignition box in foam, heat is the death of IEs.

4. I'd check that you have the fuel line that goes to the clunk and not the overflow. Make sure your tank is vented. I used to plug my vent line for transporting the plane, one day I forgot to remove it, the plane took off and flew for about one minute and then died.

5. Run your motor for 5 minutes full power on the ground, with the cowl off.

jak_kkaall

1. And I've just buyed a new bottle of Bel Ray I get a lot of oil on the plane even after just one flight. It's not the same with other minerals that burn in the cylinder better? Then this alone should be a reason to change it. I tend to take good care of my things so I would appreciate if I could see the mix from plug color. Hope to find Pennzoil in my country(is one of those in the photos?)...If I stick with Bel Ray isn't 50:1 way too risky? I mean You use 32:1.
I will fly with cowl off, already using NiMh 4,8v 2400mA LSD and didn't wrap the EIS. The tank is vented and working, fuel line to carb comes from clunk not from overflow so it's corect. By overflow I think You mean the vent line, no I didn't mess them up.
-Run the engine 5min at full power on the ground?! Can we do that? I read not to run a new engine on the ground at full power more than 10 sec I'm afraid it will ''blow up'' and will have to throw it to the trash.
- I've took apart the carb, and found that the surface of the motor where the reed block stays it has something proeminent(see pics) could this be the cause of soaking weat gaskets and bolts around the carb and maybe a lean mixture therefore the need to keep the H at 2 turn open? I'll try to flaten that surface and maybe put red silicone on every surface from carb to engine block including on rubber gaskets, have read somewhere that it can be done.
- Is it normal to press the metering lever about 2mm untill it actualy begins to rise the metering needle? What's with that dead travel?

I liked this engine a lot how it fits on the plane like a glove, did read a lot about engine baffling, walbro tunning, air presure valve routing in the fuselage, etc and I will make it work. Thank Good I know English because ther's noone in my small town with this hobby so the international forums are my friends.

jak_kkaall

Also there are three tipes of gas around here, 95, 98 and 99+ octane which one should I use? I used 99+ thinking it's the best...manual says minimum of 93, does'n say the max.

soarrich

My Feedback: (98)

With other oils you'll have to clean the bottom of you plane after 50 flights.

.That's why I quit using it, it's good oil, just messy. With the Pennzoil or any other two stroke oil you want it for a air-cooled engine, the cylinder walls are hotter than a water cooled engines, like a outboard motor. A good place to find the oil is in a motorcycle shop that deals with air-cooled dirt bikes.




I use 32:1 because it's easier to have one gas can. 40:1 or 50:1 is what most guys fly with after a gallon or so.



.
Remember with the cowl off it's going to be more tail heavy, usually not a problem, but your plane looks like it maybe a CAP 20 or 21 which have a reputation for snapping at slow speed.


.In the plane, with the wings on, no problem. You don't want to run it in a rigid test stand you could break the motor mount lugs off, or in the plane with the wings off, it'll really shake the plane without the wings.

.It would cause lots of problems



.Fill the crankcase with a rag, then file the whole surface flat. If you don think you can do it, then get a piece of glass, put sand paper on it, then pull the crankcase back and forth over until it is flat. I've done it with a file, it's really not very difficult.



-I think that's normal.

Yea, the forums really helped me when I was starting.

Truckracer

My Feedback: (19)

I'll address the metering needle issue. Normal! When the metering diaphragm moves the fork, it releases mechanical pressure that holds the needle on its seat. Fuel pressure from the pump side of the carb will open the needle as needed. I doubt the needle ever opens very much during normal operation as just a small opening can flow a lot of fuel at pressure.

soarrich

My Feedback: (98)

Less is BETTER. We have 89 here, and I just read an article that said Coleman stove fuel is fine, it's 80 octane. Higher octane was needed for big cylinders where the pressure would set off the air/fuel mix before the flame front could cross the cylinder, that's not a problem with our little cylinders and low compression ratios.

jak_kkaall

Thank you all! Didn't find pennzoil in town, unbelievable all the bike shops have synthetic oils, will search for it on internet. Until then I might give it a shot with Bel Ray but with less oil in the mix and cowl off. I've filed the surfaces of the engine block and reed block flat(they warent), made new gaskets from gasket material and applied on one side of them high temp red silicone I'l see if it helps with sealing(seems that other's done it too) You're right it's a Cap 232, so I mounted a heavy 280g 4cells NiMh 4000mA for the EIS after the engine to compensate for the cowl. I meant I'm affraind of overheating from 5min at full on the ground not vibrations but You had a good point also. Did I do a good job wiring the plug caps to the engine body (ground)see pics? To reduce misfires so I've read and smooter run.

soarrich

My Feedback: (98)

I've never seen that done on a RCXcel type ignition, the cap is grounded by the shielded wire back to the IE. I don't think the wires you added will hurt anything, but I don't think they do anything either.

jak_kkaall

There is another thread of 3 pages about this engine,on this forum also, title: ''XYZ 53-STS Twin'' http://www.rcuniverse.com/forum/gas-...ts-twin-3.html on which I haven't seen you posting like I did on this one and found out that what you posted here in 2013 at post 29 about carb tuning I was having saved in an word doc. besides another post (no.57)from the other thread abut the CDI from Kahu1958:
''One problem some people have had is the engine miss-firing intermittently.
The spark plug caps are very loose and the shielding is the earth for the CDI circuit (they may not always be in contact), if you fit earth leads from the spark plug caps to the engine it may run smoother(mine does).
(This fix was given to me by another XYZ53 engine user) '' end of quote.

soarrich

My Feedback: (98)

I think I would have used small hose clamps on each cap. If the cap is loose it will make the spark jump from the cap to the plug, a much bigger spark than use see at the spark plugs gap, that will make the ignition over-heat and burn out.

jak_kkaall

You are right, the caps, mostly the left cylinder one is loose (which had brighter plug color in the past(see pics) and now has more compresion) I mean you can lift it 2mm very easy. I don't know if hose clamps would fit because of the angle and I want if possible to be able to check the plugs with the cowl on (trough the holes that I heave) so I made a more unprofessional secure of the caps that can hopefully be put on and of with a screwdriver. It is ugly but they stay well pressed now. I sure hope that these changes I've made these days will improve this engine's performance. I wait for the weather to improve so I can go out and fly. I will post here the results. Thank you.

jak_kkaall

Six flights in two days with the cowl off and it works fine now after I:
- sanded the carb and reed block flat, made new gaskets and apply red silicone on one side of each gasket, and now the reed block isn't wet anymore;
- grounded and secured the plugs to the engine;
- corrected the timing to approx 28*;
- adjusted the carb more rich also because it is colder now, about 40-55F (H-2turns out; L-1,4 turns out. When the engine stopped in the air they were: H-1,5; L-1,3);
- replaced the bell ray with Stihl mineral at 30:1 just to see how it goes(Is the only mineral for air cooled engines that I found here as it is for chainsaws). I'll keep it for about a gallon and then maybe switch to syntetic.

Results:
- it doesn't miss fire anymore;
- 7500rpm with pelikan 20x8 adjusted at 7300 to be on the safe side;
- didn't stop in the air anymore, actually I can keep my fingers on the cylinders fins after landing so I think it is not overheating with the above settings and cowl off
- has good transition;
- doesn't feel to lose power(to be lean on H) on a long vertical;
- doesn't run very rough at low rpm so I don't think the L is to rich, more than that, as it got colder I think, it started but didn't keep on going more than a few sec. not until I opened the L 1/8. After that it worked fine.
- plugs are cleaner and not so dark. Now it remains to test it with cowl on, at high altitude to be safe.

The plug from the left that shows a leaner mixture is from left cylinder, the one with more compression. And the darker one is from the right cylinder that has significantly less compression by feel than the left one.

kmeyers

The Skies on the plane make my first question: What is your altitude above sea level? Take this into consideration with RPMs vs props by others near sea level.

It sounds like your starting to have success with this engine now.

I don't like your baffles though. They seem to aim the air at the bottom of the cylinders while closing at the top. I think you need to make the air flow over the top of the head and the first three fins completely. So I see a triangle small near the top and big near the bottom now. This needs to be reversed. Completely around the top and slightly smaller at the bottom.

I would add a very small extension to the last louver on the bottom to create a low pressure behind it to aid in flow through the large opening back there.

Great pics and work!
Keep us informed.

There is one of these engines at my field but I don't see the owner very often. As I remember he liked it a lot.