ossie

Hi everyone,
The Magnum finally gets its test flight tomorrow....

A question though.....
I can't shutoff the engine with throttle. When fully closed, engine still idles (yes........... throttle IS FULLY closed and I've tried different idle mixture settings). Is this normal ???
Would like to be able to shutoff engine just prior to landing.
Any thoughts would be appreciated
Thanks in advance
Ossie

Rudeboy

We hear this comment a lot over here...

I too had problems with that at first.

Make sure you press he carb down HARD and then tighten the screw.
The O-ring under the carb MUST be compressed, or the engine WILL suck air past it.

If the carb is tight it will stop instantaneous on the ground and after about 1 or 2 seconds in the air, where the prop is driven by the wind...

Strykaas

Hi,

i've had the same kind of troubles with another engine, but I could explain it quite easily : as you close the throttle, right before it goes totally closed, another "hole" appears and finally the carb is never fully closed. Have you ever seen such a carb ?

regards

SJN

I think it sucks air through the front bearing on mine...

Rudeboy

There is a tiny hole drilled from the front bearing seat to the carb inlet, to stop the engine from "snotnosing"... this hole, combined with a not tight fitted card could be enough to keep the engine idling...

It won't be sucking much air past the crank... there is 0.05 millimeters of clearance in diameter between the crank and the housing... that is 0.025 millimeters on either side... it won't suck much air through that with all that oil in there...

Cactus.

My Feedback: (1)

i was gonna drill my MVVS GRRT carb out to 11mm, but i saw that if i did this i would have that never closing carb problem, the hole is so big that as it closes the material left around the hole isn't over 11mm deep anymore, and the other side appears

strong

You don't have a throttle cut button on your radio. I have a 5 and 7 channel hitec radio and they both have engine kill buttons.The only problem I have is looking down for the 1 or 2 seconds to find it.This plane is fast.

ossie

Thanks for the replies. Seems I'm not the only one with this problem. I'll compress the seal under the carby and re-tighten and see how that goes. The nut that tightens the carby should really be on the other side of the housing, no room to fit a spanner due to the fuel inlet. Also you can get it with out taking the engine out.

Oh by the way didn't fly it today, maybe next weekend.

I must admit I was a little disappointed with the Magnum. I guess you get what you pay for !!!.
Those elevator control rods are just crap !!!!!!, I replaced them with 4-40 rods and ball links, one on each side of the servo arm.

I hope my disappointment turns to a big when it finally takes to the sky. I know the Eurosport and P160 will when it arrives tomorrow. The Magnum might sit around for a bit longer.
Anyone want to buy a Magnum !!!!!!!!!!

Cheers
Ossie

Cactus.

My Feedback: (1)

i do have kill switch, but i wouldn't want the other engine going like hell while i flicked it and waited for it to cut, then try and recover from the flat spin

i was a bit wary of those elevator runs when a mate got his one ( one of the very first Magnums ) he used it and never had a problem in two years, neither me with mine. just have to cut them the right length so the wire in the end dosn't cause a problem, his was cut so the wire never went in the fuz, mines cut so the wire never leaves

ossie

Hi phillybaby,

I did keep trying with the elevator control rods and tried the methods that you and you friend has used, but the bends where they exit the fuse was just too sharp. To give you an idea, around 40deg change of direction from the fuse to the control horn on the elevators.
The inner rods were binding and putting too much strain on the servo. I had no choice but to replace them.

Cheers
Ossie

Cactus.

My Feedback: (1)

ahhhh, you can either, twist the horn round, or like my mates with the wire totaly outside, bend the wire. both work ok. i really didn't like the rod, or the connecting bit, but didn't have a choice at the time but to use, then i found it's not all bad.
when it comes to ARTF's, use the bits you want, replace what you want

Rudeboy

I was sceptic about the elevator rods too in the beginning, but they have worked flawlessly so far...
I didn't use the metal rods you have to push into the plastic though... that wouldn't work... I just threaded a couple of short pieces of M2 rod into the plastic...

ossie

No amount of wire bending or twisting control horns would reduce the excessive binding. The direction of travel when leaving the fuse was towards the extreme outside of the elevator :stupid:
I guess it may have worked if I mount the control horn out there.
Cheers
Ossie

LGM Graphix

My Feedback: (22)

make sure when you put the elevator horns on you have them so they are running the same direction as the pushrods, not perpendicular to the hinge line or you will have major binding issues. My Magnum works fine with the stock elevator setup but be sure that the horn is in line with the pushrod or it will bind like mad

ossie

Hi everyone,
Still can't shut the engine down with throttle. Compressed o-ring (under carby) as suggested early but made know difference.
Anyone got any other ideas ????

Had its first flight today, came home from the field with a big
First launch almost ended in tears but managed to catch it in time, its got heaps of torque roll to counteract. Second launch was not that bad as I was ready for it..
The first two flights went really well not much trim to apply for straight and level flight............my god it takes up some sky, the whole club was watching this thing streak across the sky.

Third and fourth flight was off a dolly I constructed....and man....I'll never hand launch this puppy again......an awesome sight watching this thing power down the runway then pulling vertical and rolling on the way up..............

As I said earlier, I was a little disappointed with the kit, but the flying certainly makes up for it, I've still got a *&#$..............
Cant wait till next weekend..................
Cheers
Ossie

Cactus.

My Feedback: (1)

hows your idle? one here was about 700rpm, to do this make the bottom end richer, the pick up is still fine but it idles propperly, maybe new engines are like this now i don't know, but these came with an idle of 1-2K
the lower idle should also help cutting...
but why do you want to cut the engine? fly the tank out last big dive WILL cut the engine

Rudeboy

Philly...

Somehow I find your statement about a West 50 idling at 700 rpm a little hard to believe...

2K...? Ok, I might buy that...

Cactus.

My Feedback: (1)

i was holding the tacho, i'm sure it said 688, but i didn't think you'd believe that.
stop making me doubt what i think i saw.. i'll have to double check now lol