I just ordered a Tower Fun 51 profile plane and am considering both of these engines. By the numbers, the K&B sounds better, but a 48 with 2 HP? I find that hard to believe. I have also found much praise on this board for the Irvine. I want this plane to have as much aerobatic capabilities as possible. I would like any input on either of these engines to help me make the decision. Thanks in advance for the help.
The K&B does put out that much, but is one of the heaviest engines in its class. Another one to consider is the GMS 47. Nearly as much power but 3oz lighter.
I own both engines, so have some knowledge of them. The K&B likes to turn fast, so if noise is a consideration, go with the Irvine. Another point in Irvine's favor is that since K&B is now owned by RJL/MECOA, getting spare parts may be a problem. RJL charges about seven bucks to send you a five buck part! Irvine parts can be accessed either through Sig in the USA or Just Engines in the UK.
The only reason you see more praise for Irvine is that there is more of them. K&B closed its doors shortly after selling its first batch of .48's. Mecoa now own's K&B and are once again selling them but mostly by direct sales. Some are not comfortable with the Perry like carb, but it works great once you get used to it. Irvine got its start by modifying K&B engines for racing.
IMHO, the reason you see praise for the Irvine is that it's a great engine. You'll be happy with either but I choose the Irvine - I like the red case .
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