jak_kkaall

Thanks, well I'm at 800m, half a mile altitude, the pressure is lower right? So I should get more rpm? Regarding baffles, I don't know why the plane has this triangular shape if the 1:1 scale has also a boxer engine in it. If I would have followed the triangular shape it would have been even smaller at the top of cylinder, but instead, I followed exactly the outer edge of the cylinder and doing so it didn't came out as narrow at the head as it would have been if followed the cowl's holes. Making the baffles wider at the top would make the air go around the cylinder. The video that inspired me, besides reading a lot of threads about this was this one: https://www.youtube.com/watch?v=bfSv0V7r4HA I think that in this video it sugests that the baffles should not be wider than the edges of the cylinders shape not with more than 2 mm especialy at the bottom because the air will go around them on the easiest path, my baffles are exactly at about 1-3mm from the outer part of the cylinders fins, and not following the triangle shape in the cowl which would have been much easier to do, I think all the cylinders front shape is exposed to the air. About the extension at the last louver, I thought just about that several times, good point. About 3-4 months we have snow, and it's something really fun about landing or take of from snow, this way I don't get to stay in the house and wait for the spring. Thank you for the sugestions, I will consider them.

Me in the winter...https://www.youtube.com/watch?v=bGyoiWCIg2g Enjoy!

jak_kkaall

I've made an extension to the last louver on the bottom to better pull out the air from the cowl. It seems that with the cowl on my rpm dropped slightly with about 200-300 rpm. Now I'm getting between 7000 and 7200 rpm. But on the last flight I've opened the H about 1/8 and it seem to have the power back. With the cowl off it seems to have slightly more power. My thoughts were at the air not getting so forced into the carb air intake with the cowl on and thus the loss of couple rpm, but I might be wrong. The cowl pressure can't affect the carb diaphragm because I'vre routed it inside the fuselage since the beggining. Or maybe the Stihl mineral is crap and not like Stihl HP Ultra that is synthetic and much more expensive. Maybe the Bel Ray mineral is better, I will try to fly on it again just to test it. I left the Bell Ray because of the mess it was making. I would go to synthetic but I don't know if the break in is over. Some recommend 6 gallons to completely run in the engine on mineral, others say 1-2 gallons, others start with synthetic from the start so it's as much opinions as people are. Now I'm getting about 7200rpm with a 20x8 at 800m altitude and 50F/10C temp. Can't tell if it's good or poor.

jak_kkaall

Are there other users of this engine? What performance do you get like rpm with what prop? What spark plug colour and carb setings do you have?

Octopus RC

My Feedback: (2)

Hi Jak_kkaall the 20x8 you are using may a bit small size for this engine !
We use XOAR 22x8 and get 6300rpm .
Carb settings are both L and H needle at about 1.5 round position !

jak_kkaall

Thank you. Is it ok to leave the H at max.rpm or 200-300 rpm below? And on the ground a couple of times if very slowly increasing rpm, at about 5500rpm it has some kind of interuptions I think that's when the second cylinder is sincronizing but it stopped. And also during flight, at about the same rpm it stopped a couple of times. And others say the same thing on this thread. Why it does that? The L is not opened enough? It has to be richer?

jak_kkaall

Well I also get 6300rpm with 22x8 but this translates to about 8 kg of thrust because my plane has 8 kg and it barely keeps it in hovering, sometimes it drops slowly at full rpm! And the engine is advertised at 10-11kg thrust! How?

Octopus RC

My Feedback: (2)

Yes, a 50cc range single head engine will provide around 10-11kg thrust ! But a twin probable not !
How many hours of your 53 had run total ?
Maybe you need new piston ring to make it powerful again !

haltom

My Feedback: (1)

After 4 years with no flying I hope to pick up the hobby again as I’m close to retirement.
I have two XYZ 53cc twin, and they used to run perfect and smooth over a couple of years.
I’m using NGK sparks, ignition from sds hobby(not the xyz one), and prop 22X10.
My Big Stick is about 10,5kg and it flies perfect (from my point of wiew).

Well i Norway it’s getting cold, but I wanted to try to start the engines which have been stored in a garage for approx 4 years.
First they would not start at all, fired when I put som gas into the carburator but that’s all. The carburator will not suck fuel.
Finally after disassemble the carburator to check if the needle was stuck I manage to have one engine run, but max for 4-5 minutes.
I had to borrow an electrical starter from a friend (first time I have to use a starter).
I had to run with some choke, and I could not trottle it up, then it stopped.
The gas is new and the gas tank is clean.
What should I do?

jak_kkaall

Hi, I'm no expert so I might be wrong but it seems to me that these signs along with the long period might show a hardened carb pump diaphragm or membrane. It has lost it's elasticity that's why it doesn't draw fuel when starting, it dies when throttle it up (no fuel draw), needs chocke to draw fuel because the diaphragm doesn't do it annymore. Mine acumulated garbage in the carb filter, despite heaving a filter on the refueling line, and died in the air (lack of fuel). The pump diaphragm had wrigles and someone told me that's the sign that it should be changed. So I've ordered a few sets of carb rebuild kit that, besides other parts, it contained also the exact pieces that our 53cc twin walbro carb uses. I've replaced the diaphragm and also the membrane on the other carb side and works fine since then. I advice you to do the same. The kits that I've ordered are two out of the folowing three links, can't remember which. You might want to visualy check which one contains the exact parts for your carb, chances are all three have them. I've ordered 4 kits in total just to have them and because they are incredibly cheap, considering that all the kit is 2-3 euros and at my local Stihl chainsaw store they charge 12 euros for one membrane! As a note: I always empty the lines and carb (run the engine until it stops) before going home. If not, gas will evaporate and gume up on all the carb insides but you probably know that.
https://www.ebay.com/itm/WALBRO-K20-...97.m4902.l9144
https://www.ebay.com/itm/Carburetor-...97.m4902.l9144
https://www.ebay.com/itm/Carburetor-...97.m4902.l9144

haltom

My Feedback: (1)

Thank’s I will try to order those parts :-)

Octopus RC

My Feedback: (2)

Hi Haltom , there has a tinny valve in carb , usually we use WD40 clean carb which has stored very long time .
Sometimes WD40 will help to make it alive , sometimes may not !
Here is the link of XYZ 53STS carb , it`s also a good replacement carb for DLE 55 .
https://octopusrc.com/shop/WT805?search=WT805

haltom

My Feedback: (1)

Thanks for help. Gasket/membran kit is ordered and expected here at the end of december.
To cold any way, so I have to wait until spring I think.

best regards tom.

jak_kkaall

I've recently added to my 53twin the Bjorn (Bowman) rings and a velocity stack as others recomended. I have to say I'm glad I did because it increased th rpm with a 22x8 wooden prop from 6400 to 6700-6800rpm don't know how much of it is ring or velocity stack related. Now I have some power reserve when hovering my 8kg CAP 232 and I'm not so close to full throttle when hovering as before.