Why not gasser rear enging?

While historically there are cooling issues such as with Foretravel and FMC, those problems are not insurmountable. Of course the problem is, that any new idea takes awhile to be trusted, especially when it has a history of problems. Workhorse was obviously keenly aware of the problem, but felt like the gas engine and the industry as a whole, had come of age, where it was practical to do it right. Half the heat problem is the fact that in the 70s through the 90s, gas engines where very underpowered to handle a large coach. Between that and coach builders being very careless about air flow design didn't help. In contrast to history, the 8.1 has plenty of power for the size coach. The piece volume is great enough for the chassis builder to specify to the coach builders what must be done. So, the UFO came out. Workhorse built 3 chassis to run tests in the AZ desert. 1000's of miles were put on those engines to prove out the reliability. As it turned out, the engine had no trouble operating in those conditions, and as a matter of fact, when those test engines were removed from the test chassis, they were sold on Ebay and at least one I know is still going strong. I almost bought one of those test engines, but decided I didn't want to mess with the more complicated ECM.

Yes, the UFO was a great idea, and hopefully will come back. Even though the RV market tanked, which caused the chassis to die, in the end, it may not be all bad. As time wears on, the chassis has opportunity to prove its self, as well as create a demand for something that is not available. From a marketing standpoint, demand with no supply is a great opportunity. There is a revamped version of the 8.1 that has been developed to meet pollution requirements and is targeted to the RV industry. It has even more power, so the possibility for the reintroduction of the UFO chassis is wide open.