The magnets are 5/16 dia by 1/8" thick. They are amazingly powerfull, it is all you can do to pry two of them apart. I have previously used 2 in each corner of a hatch, (total of 8) with good success. Of the 2 in each corner, one gets recessed in a gusset on the top of the fuselage, the other in the hatch. This time I thought I would try mounting them in shear on the ends of the hatch, with corresponding magnets recessed in the rear top of the firewall and the front of the bulkhead behind the hatch. This would make a total of 4 and eliminate the need to install gussets to hold them. I've set them up temporarily and it takes a really good pull to pry the hatch loose. It's an experiment and I may find that I need more to make it work...

Then I started worrying about whether it would interfere with the ignition module, which I had planned to mount on the top/front of the firewall, immediately in front of my magnet, ~1/8" of plywood separation. Great Hobbies in Edmonton, where I bought the engine says "no problem" but I wanted to get a few more opinions before I commit to mounting my ignition module and perhaps de-programming it or something.

Opinions appreciated...

Regards Ron