Originally Posted by
1967brutus
It is imperative to have at least SOME form of "calibrated orifice", adjustable or not, because the solenoid itself has a full flow capacity sufficient to feed (estimated) a 30 hp engine.
Which means that in ordr to modulate the fuel for, say, a 3 hp engine, the solenoid has to operate in the lower 10% of its dutycycle. In itself not too bad but it would require custom calibrated electronics or it would go at the cost of resolution in the curves.
That's what I figured, why I wanted to relocate the needles, if I can intersect the fuel paths. I can cut up the buggered up carb and take some measurments if I need to.
Originally Posted by
1967brutus
I'd expect the original M-tronic carbs to have a fuel orifice tailored to the engine range it is intended for.
I was not aware that the M-tronic carb is that much larger than the equivalent Walbro. But I would think that building a suitable header between engine block and carb would allow for relocation to any more suitable location?
They do, there is a fixed orifice on the lo / intermediate fuel circuit at the bottom of the solinoid chamber. There are two orifices actually, one feeds the main jet, the other feeds the idle / intermediate jets.
The m-carb body is quite a bit bulkier than a walbro wt series carb, even after removing the choke lockout mechanism, and the choke position switch. I don't have an image available to show you the gaui f50r installation in the Super cub, it's a shoe horn fit to begin with, with the wt carb. To fit the m-carb I would have to move the engine forward about 3/4" (19mm). I like scale apperence, and moving the engine that much forward, would make the cub way too long in the nose. I'll get something sorted out.
Anyway how you doing mate? I haven't seen much activity from you for a while. Hope things are going well with you.
I had a bad experience with the J3, one of the receivers failed, just shut down, and left me with half the control surfaces working, shut down making a left turn. The right aileron, and elevator half were stuck in a downwards position, about 20% of their travel. Rudder and throttle still active. Ended up forcing a landing with a bad approach, stalled and bellied in on the gear, caught the right wing tip on the edge of the rwy. Fortunately minor damage to the wing tip and collapsed the gear. She's good as new, but I switch over to jeti for the J3, still using the 18sz for the SC.