Looking For Information On A Bomber Collision

I hope someone can help please with some more information.I am looking for information for someone whose Great Uncle Harry E Hancock was killed in a bomber collision .
If anyone has any more information of photos that i could pass on it would be wonderful ,Thank you.

http://www.americanairmuseum.com/person/89040 He was killed ” Killed in Action (KIA). B-17F #42-29747 ‘Rikki-Tikki-Tavi II’. Mid-air collision during assembly.”

His gravestone is at Madingley American Cemetery Cambridge
Thank you 🙂