I use magnets to hold the hatches on the majority of my glow planes and have not had any problems. I use 1/4" square magnets imbeded in the fuselage and a metal strip on the hatch. Each of the magnets has a holding "power" of 6lbs. I usuely use 2 on my 40 size planes, however I do have a 60 size (relatively fast plane ) that I use 4 on since the hatch is about 4" x 7" .