Our model diesel engines are about the only ones that come close to operating normally from detonation because of their peculiar method of having a combustible mixture that's triggered by heat of compression. All the mixture feels the same compression so in theory it could all start to burn at the same time....no flame front. In practise though I suspect that whatever's close to the piston and head stays a little cooler so it'd probably first ignite somewhere near the middle of the mixture.

I've never heard detonation with a glow engine but it's supposed to sound just like what Jim said...a frying egg sound. But you'd need to be pushing it to the limit to make it detonate...too hot a plug, lean mixture, too much compression/nitro, loaded so max revs are close to the max torque, any of them in combination could do it. We really can't get pre-ignition because that needs a hot spot and there's nothing that can get hotter than the plug itself. Maybe a 4 stroke could get the exhaust valve hot enough for pre-ignition if you really tried.