I have spare Vlach ignition (thanks Pe) that I will use for one of the weed whacker experiments. I made a hub thick enough to accomodate magnets for pickup. It is 9mm long and 31 mm diameter.

Questions:
How do I put a magnet in there (actually two magnets, as Vlach requires 2 magnets)?
What kind of magnets?
What size?
What strenght?
How to mount so it doesn't fly away?
What distance should be between pickup sensor and the magnet?

RysiuM

Heres what I'm using:

Aluminium hub with 5mm counterbore 2mm deep (for the straight sided section) radially. I use dia 5mm depth 2mm neo magnets and stick them in with epoxy, holding them in place with tape over the top while the glue dries. The idea is the magnet sits flush with the diameter of the alu ring. You could just use a drill to make the 5mm bore as a poited end to the hole is no problem, it just fills with epoxy.

If its a hall pickup the gap between the magnet and the pickup should be 2mm max, the smaller the better.

Also check as some hall pickups only work with a N or a S, some work with the magnet either way round. Just try moving the magnet past the sensor first to make sure you get it in the right way round!

You ported the Poulan yet...?

Cheers,
Rich

I found that after a couple minutes of dunning the hub gets quite warm. The heat transfers from the engine to the hub. I don't know the temperature, nut neo magnets are quite sensitive to the heat - standard NdFeB can hold only up to 80C (176F). Should I use SH - good up to 150C (302F)?

If its a hall pickup the gap between the magnet and the pickup should be 2mm max, the smaller the better.

Vlach II needs two magnets - one oriented N the other S. It uses N to fire and S to reset (or the other way around).

Rich, so many projects, so little time. I'm working on OMP Edge Wing for my H9 Edge. It leaves me almost no time for anythng else. The idea is, that my H9 Edge 27% (the discontinued one) has lots of power frm Brison 2.4, but it is heavy like a brick. It flis IMAC OK but I wanted it for some 3D too. So i got a wing kit for OMP Edge 80 inch span that I'm modifying for H9. See the thread [link=http://www.rcuniverse.com/forum/fb.asp?m=3436984]Wing kit from Edge 540T 80inch span[/link].
I started this question as I need to order the right size magnets from George.

RysiuM

I used Neo as I already had them stuck to my toolbox! they were not used for any patricular reason other than they are very strong. What are SH magnets...? I might try some. So far I've had no probs with the neo though, but I'm running with no cowl at the moment so the magnet hub does not get over about 50 deg C.

Cheers,
Rich

NeFeB are rated based on operating temperature::

Nxx (max N50) rated for 80C (176F)
NxxM (max N48M) rated to 100C (212F)
NxxH (max N45H) rated for 120C (248F)
NxxSH (max N42SH) rated for 150C (302F)


here in CA the summer time is over 100F and in the sun over 120. It doesn't take much to fry Nxx magnets - happend to me when outrunner got hot just sitting in the sun.

RysiuM