Can I develop a site like this with Wordpress?
 

It's for people that build those model airplanes and ships. Once they signup they can upload photos of the stuff they made (different post for each model) and explain how they made it and whatnot. There would be featured image mandatory for each post so when you say search for P51 you get Mustang thumbnails instead of usual list of matching posts with titles and some text.

A few questions:

1. Supposedly there'd be tens or even hundreds of members and much more posts and comments so how long before the whole thing goes too sluggish?

2. Can I create a custom new post form for them, that'd differ with new post form from WP admin?

3. Is there a smarter backend for this? (perhaps forum software?)

Yeah, you can do all of that with WordPress. It's just a php/sql cms where everything can be modified, it doesn't even have to be a blog.
I'm sure there are better options for what you're doing, but that depends on what you know and how much work you want to put into it.
The sluggishness or not will mostly depend on how you optimize the site/images/plugins/theme/etc and the hosting you're using.

thank you for your input

maybe you can try to look at forum cms, like phpbb or wiki cms. Wordpress in a box not so good for multiple user conversation.

Wordpress sounds perfect for what you're wanting to achieve and should be more the capable of handling a few thousand blog posts with comments on each, that is providing you have suitable hosting.

To display the thumbs on the search results page is also simple enough to achieve if you have the knowledge, there's plenty of articles on wordpress/commmunity that will explain it easy enough.

Yes you can create a custom form that will allow users to post outside of the wp-admin, there's a few plugins to do just this, try searching guest posts form or something similar.

I'd say from what you state your requirements are, stick with wordpress.

thanks folks now pretty sure about going with WP as planned

Yes, everything you want can be done with Wordpress.
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