Pipe/manifold length on the West Eurotech 50 V1
 

Hi!

I have been sneak peeked ("tjyvkollat" in Swedish) on this forum for a long time now but this will be my first topic.

I purchased a MagnumR with the West 50 V1 engine about one and a half year ago now, but I flew it myself for the first time in the late winter this year (I think it was mars) when it still was a little snow on the ground to land in. I am a member in a club that have access for a real airport (a small one) with a runway made of asphalt. That´s why I have put a carbon fiber landing gear with F3D wheels on my Magnum.

Anyway, I have been used a balanced APC 9x7 so far and I think I will be using a APC 8x10 for the comming flights now. I have read a lot about the Magnum and the engine on this forum but there is one thing I can´t understand, they say that if you use a 8x8 propeller you have to cut off 1/2" the mainfold and similar on the pipe because the engine will not get used of the pipe to 100% if it´s in the original length. But if you use a 8x10 propeller you don´t have to do anything. When i run the engine with the 9x7 propeller the engine has no problem at all to "go on" the pipe and with the 8x10 comes into the pipe already with a litte more then half throttle and the plane is still on the ground!? With full throttle the engine will not go very well, the rpm just goes up and down even how much I open/close the needle.

Should I short the pipe (how much?) or should I use a larger propeller? (9x9)

With a balanced APC 9x7 the engine will run up to somewhere between 17 and 19000 rpm depending how much I lean/rich the engine, with the 8x10 I don´t know yet because there was not enough sunlight and my rpm checker needs to operate in direct sunlight to work well.
I use my own home mixed fuel with 10% nitromethane and 18% syntetic oil, and yes the engine runs cool enough with that syntetic oil I use, castor oil is not needed.

/Eric P

RE: Pipe/manifold length on the West Eurotech 50 V1
 

Never hve delt with that engine, but OS, Webra.Super tiger I have. When you change the pitch you increase the load on the engine os it doesn't breathe as good. I alway start buy cutting 1/4 inch off at a time time till I reach my goal on max rpm. But there is a draw back going to far and you will start blowing plugs, You might not notice a big increase in the first 1.4 inch but try throtel responce and see if engine comes up on to the pipe if not cut anouther 1/4. My webra .36 with aps 8.7 is turning 18500rpm on a tusnami Q migit, header length aprox. 3 inches
P.S couldn't resist included pic of New Dimond dust haven't flown yet. Running Webra 40 Hiper .40
Good luck

RE: Pipe/manifold length on the West Eurotech 50 V1
 

1/4" that is about 6mm...
Well that was what I expected but I just want to hear if there was someone else with the West Eurotech 50 V1 who had the same problem that I have. If you read the instructions - no cut off will be needed if you use a 8x10 propeller.

The engine will not blow plugs until the pipe is too short, doesn´t it?

That were nice planes you got but I would had a rear exhaust engine on the dust with a tuned pipe if it were mine!
Anyway, good luck with the premiere flight.

/Eric P

RE: Pipe/manifold length on the West Eurotech 50 V1
 

Keep cutting until it peaks... take proper measurements. You can use a flashlight to make your tach work, no need for sunlight.

Use light props, because the West really likes to rev... an 8x8 or 8x9 or a cut down Q500 prop.

The engine will blow plugs when it's running too lean. But at over 21000 rpm, you'll be burning plugs regularly any way... don't expect them to last forever.

RE: Pipe/manifold length on the West Eurotech 50 V1
 

Using light props is a good point, APC makes great sport props for the money, but they are heavy. I have not tried their carbon props yet, but I have run maple and other brand carbon props. There is a performance gain with having thin blades made out of stiff material. You can only expect extreme performance from the best materials for the job, and that would be carbon, followed by maple that has been shaved down to being dangerously thin. The XxX number on the prop doesn't tell the whole story, the blade design and weight have a lot to do with the overall picture. The difference in performance and tunability between using a heavy, thick blade sport prop and a light, thin blade competition prop is dramatic. Heavy props are very hard on the engine, especially the crank pin area.