With my Aerocell Super Cub the plane never took serious abuse, but the wobbly landing gear of the Great Planes Gee Bee has put Aerocell to the test on more than a few occasions. I have been impressed and that's not easy to do. Similarly my Stamax P-51 bonked a 50' tree on the second flight without noticeable damage. My EPO Banana Hobby Corsair took a pole in the face at high speed with almost no damage to the foam itself, though the motor wasn't happy. All this has made me realize how different, different "EPO" foam really is.
There are other key attributes that make some foam better to work with than others. For example, a coat of gloss spray paint brings Aerocell to a glassy sheen that the others can't match, though the Banana Corsair comes close.
Weight is difficult to access without large standardized blocks of foam, but a general difference seems noticeable and important. The Carbon Z Yak 54 and Parkzone Extra 300 flying brick suffer greatly from heavier, weaker EPO that doesn't finish well and mars easily.
Interestingly, when all the attributes were scored, the foam fell into three groupings. The world as I fly it:
EPO Foam | Weight | Finish | Strength | Score |
Aerocell | 8 | 10 | 10 | 93% |
BH Corsair | 2 | 10 | 10 | 73% |
Starmax | 5 | 7 | 7 | 63% |
J-Power | 5 | 6 | 7 | 60% |
Sky Angel | 5 | 6 | 7 | 60% |
Z Foam | 4 | 3 | 5 | 40% |
Key:
Weight = Self explanatory
Finish = Glassy or textured when painted?
Strength = How big a crash or cartwheel to break in two? How easy to mar from routine handling?