Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Earlier this week, when Foolish defense analyst Andrew Tonner asked us for our favorite ideas in the defense sphere, I nominated Lockheed Martin (NYSE: LMT) and my Foolish colleague Katie Spence offered up Northrop Grumman (NYSE: NOC). Taking advantage of the comments section, one Fool fired back that Oshkosh (NYSE: OSK) was the real best in defense. So how's that idea working out?

Oh, about 15% less well than it was yesterday.

So what: Oshkosh reported earnings for its fiscal third quarter this morning, and the news was not good. Sales slipped a relatively modest 13%, but profits were down big time: nearly 68%, to $0.75 per diluted share.

Now what: CEO Charles Szews pronounced himself "pleased" with the results, but I doubt investors share the sentiment. Szews plans to deal with decreased defense spending in the U.S. by "capturing the full benefit of the economic recovery expected in our non-defense markets." If he succeeds, the stock could be cheap at its current 6.4 times trailing earnings. However, free cash flow at the company is lagging reported income by a whopping 19%. Value the company on its FCF, and take into account Oshkosh's still-sizable debt load, and the stock looks less attractive at an enterprise value-to-free cash flow ratio of 12.2.

That's a pretty penny to pay for a company that most analysts think will grow at only 10.5% per year over the next five years. With defense spending weak and the economic recovery less than certain, I'd be cautious about buying into Oshkosh, even at today's newly discounted price. There are better places to put your money today.

Can Szews steer Oshkosh to success? Add the stock to your Watchlist and find out.