This is the Yak 110.
Strapping two airframes together to create an entirely new airplane has actually been done quite a few times in aviation history. You may know about the famous F-82 'Twin' Mustang. Using two Yak 55's, the team assembled this hybrid that includes dual controls from either cockpit. Recently the aircraft made its first flight after a year of construction and three years of planning. Test Flown by Len Fox, an experienced test pilot with over 54 experimental types under his belt, the patchwork Yak performed almost flawlessly. However, that's not where the story ends - these 'Fat Tire Cowboys' (as the team like to be known) have even bigger plans than merely strapping two aerobatic aircraft together. Namely, they want to add another engine to make it a tri-motor. The plan was to slap a jet engine on the underside of this thing.
The artist's impression of how the finished bird will look gives a good indication of the uniqueness of this project. This, however, is nothing on actually seeing and hearing the results for yourself. This project was conceptualised by display pilot Jeff Boerboon. Now the third engine has been installed, the Yak will be gearing up to perform at airshows in 2018 in the hands of Jeff himself. What with the noise of not only the two radial engines but a turbojet as well, the spectacle should be quite something to say the least.