SJN

Hi Guys

I love my Magnum, but the neighbours hate the west V1

Which engine would you reccomend for the magnum?
I know that I will loose lots of speed, but the only alternative is to change to a quieter engine.......and no electrics

I was thinking about the OS 55AX stock muffler and maybe a 9x8 or 10x10 prop ?
Does it sound ok quiet with the stock muffler running at relative high rpm ?

What about the Webra speed GT ?
I just think the webra mufflers usualy arn`t as quiet as the os mufflers?

evan-RCU

You do know the Weston is a Webra Speed .50 right? The noise is all muffler related. A quiet tuned pipe will get some of the noise down but a true muffler would be best, unfortunately it also slows you down. Are you running the Weston pipe? It's quieter than most.

Strykaas

Is it quieter than the japanese 3 chambers Yusa / Hatori pipes ?

SJN

Yes, I bought the combo with the west pipe.

I too think it sounds ok......


I have actualy tried the V1 on a stock webra muffler, but the engine runs like crap, and is very difficult to tune.
It must be ported to run optimaly with a pipe

Heres a video of it :
http://www.youtube.com/watch?v=7W99SjeWFkk

I was flying it slow in the video.
Sure the engine runs, but not as smoothe as i wantet it to


Here is a very short clip of the same model and engine with the pipe
http://www.youtube.com/watch?v=C9PxFc2XJ3E

evan-RCU

Yes Weston does put in a cylinder timed for a pipe.... You can tune a muffler but it's not easy...

BiggerDanno

The instructions that come with the West specifically say not to use a muffler on the engine and that it's not designed to run under 16,000 rpms.
I think you would overspeed the 55 with a 9" prop. I'm currently running a 55 with a tuned pipe that turns an 11x8 at 14050 on the ground. A 10x10 should work well though.

SJN

Well, here is the 55ax
Iy fits nicly in the magnum.

Which prop would you reccomend on the magnum airframe ?

What do you think of the graupner cam 10/8 prop ?

SJN

Got the os 55 ax started today, and it is a very smoothe running engine.
Battery in my tach was flat, so i did not take any rpm messuremants

I ran one tank through the engine on the ground, and then flew 2 tanks, before fog covered our flying field today.

I would guess it was flying about 110 mph, but the guys watching said it realy flew like a rocket
Engine is still running quite rich, so i have not seen the potential of this motor yet.
Ill try some other props when the engine is run in.

But the sound level is fantastic. Im happy I chose this engine.
With the low noise of the engine, you can realy hear the wind noise whistleing around the airframe

vicman

My Feedback: (10)

I would step on mine if it only did 110[X(]

SJN

heh...it was just a guess

The other guys thought it was going 200

Maybe it is faster, but the engine still has more grunt to show

vicman

My Feedback: (10)

200 is a long stretch for sure. 140-150 is pretty consistant from my experience.

rmenke

My Feedback: (13)

SJN:

Gotta agree with vicman, but thats what you get buying a pure sport engine and ask way too much from it. Had you gone with the Webra 55, Jett tuned muffler and apc 10 X 10, you would be owner of another 2,000-2500rpm. The 55 should not pull a 10 X 10 well, but something about the combo just flat works. My webra carries the 10 X 10 well, and pushes a Jet 60LX in a identical airframe. Think I would burn up the Jet with that size prop. ENJOY

evan-RCU

145 is what you get level with a stock Magnum with a good motor like a Jett or the Weston .50.... The 55AX is probably 130-135...

SJN

Yes, I know the webra would have been better speed wise. But what good is it, if Im not allowed to fly because it is alittle too noisy

Ill try get some video of it once the engine is fully broken in.

freakingfast

My Feedback: (3)

There are guys running 10X10 APC with a 55AX on a Viper, the Magnum is at least as "clean" so it should work too. They tried less prop but went back to the 10X10. I think they were running the stock muffler too. With a Macs quiet pipe or with the special order double quiet pipe you should see a 800 to 1000 rpm gain but is the cost worth it by the time you get it to DK?

By the way, did you happen to notice the long flight time with the 55AX

I have not seen the Graupner "Fuel" props here in the USA.

Viper Video W/55AX& 10X10APC:
http://www.youtube.com/watch?v=zdf1E...eature=related

SJN

I just ordered some 10x9 and 10x10 props
My local hobby shops dont have those sizes in stock

And yea, it does fly at least twice as long now....the 55ax only sips fuel

PAK26499

My Feedback: (3)

SJN

I traded the magnum and os 55 for a brand new saito 72 a long time ago.....


Flew fine with the 55, but it was not as exciting as when it had the West 50 and pipe on it

PAK26499

My Feedback: (3)

Thank you for the info