Icar novel, what should I do with it?

Get feedback now, it is easier to incorporate it before you finish.

I've tended to use GDocs for this sort of thing and letting others edit so they can stick in corrections and or comments. GDocs has pretty good revision tracking built in so you can track changes look at who added what across multiple versions and it's low impact since it's cloud based nothing to download no compatibility issues and you can use it on ongoing work and add to it as you see fit.

To address the more general thrust of your post, getting good feedback on writing is tough, I've been doing some writing just as a hobby off and on for three years now. In that time I've put up 9 stories of various lengths from 10k to 150k words in length and comments where you get any are either short positive but useless ie "Great Story!!!!" or occasionally long negative diatribes on how I am wrong but without any hint as to how to improve. Generally speaking getting useful feedback is tough people don't know how to give it, usually your best bet for this sort of thing is other authors who understand what you are looking for or if you can find one who will do it for free editors who offer this sort of advice professionally.

I've not really highlighted the story writing I've done to the group at large for a number of reason chief among them it's not something I feel all that comfortable sharing with people I know due to lack of confidence in my ability as a writer. I also quite like the perceived anonymity of writing behind an internet pen-name where no one knows you or have any preconceptions about who you are. I also didn't want to burden people with it, since giving honest feedback about something like this is very hard for friends to do.

What you really need to improve your story (and I speak from experience) is someone un-invested in the story who can be brutally honest. The best (albeit painful) way you improve is to have your ideas and plans shot down in flames so you can take what worked from the wreakage and build a better story or throw away an idea that just doesn't work and start again from scratch a little wiser. Friends can find this tough to do, with something like this where you have devoted a lot of time to it can be painful to have someone stomp all over it and naturally friends tend to hold back from that which is not what you want if you are going to improve as an author.

I have had stories that I spent a lot of time on that someone has taken one look at and blown completely to bits. It hurts but it's useful, writing is rewriting and a honest take on a draft of the story means that after the pain has faded you look at the story with open eyes and can move forward on the next draft or know that the story is a dead duck and drop it and move on.

There is a multitude of advice and books and comments on how to write and why but the best thing I've learned about writing is just to keep writing. Some stories work others don't but there is always the next story that will always be better. As for getting published that is a very tough road very very few people manage that and only the tinyiest fraction on their first work and of almost all were professional writers of one stripe or another (ie advertising writers or marketing writers or journalists or roleplay rule books or some such) so it wasn't really their first published work. Try for something a bit lower than publication like magazines or competitions with the internet there are a multitude of options these days a lot of the big publishing houses now have online web magazines you can submit to. Or you can try the self pub route some aspiring authors have had success this way, often on the back of a podcast of them reading their work.

I'm rambling a little so I'll stop now :)