Tropit, you sent me to Google once again
I read this:
There could be a few possible reasons for a chiffon to collapse:- The egg white hasn't been whipped enough. ...
- It's possible that you over blended the egg white and egg yolk mixture. ...
- It's very likely that the oven temperature isn't high enough.
https://www.allrecipes.com/recipe/7892/chiffon-cake/
the first review seemed helpful also.
Since we have started gathering about 2 dozen eggs per day, I will give this recipe a try.
Thank you for your insights.