Oops, I don't want to represent myself as a rotary expert--I am not. I am just an observer at this point. It is true that I am going to install an RX-7 13B rotary engine in my RV-7A, but I have not yet ran the engine at this point. So, anything that I say should be taken with a grain of salt--the ole 2-cents. These are just my observations.
Obviously, without having a running engine, I don't have any first-hand information about fuel consumption. I only know that the rotary has a bad reputation for fuel economy, and there are few people who can refute that. However, based upon the feedback from Tracy Crook, it appears that the numbers are not as bad as people would suggest. Tracy has determined that the rotary can be leaned way beyond what would be acceptable for a Lycoming, and I think he cruises at around 5-6GPH. But let's be honest here, Tracy is cheap, and doesn't mind crusing around 140Kts. If you pull the power back enough, your fuel consumption will go down, and you will get reasonable numbers. These numbers hove no meaning unless you fly side-by-side. Of course, this was done a few months ago, and in the fuel consumption and noise categories, the rotary lost (RVATOR two issues back). The good news is that while the fuel consumption was higher, it was just marginally higher (something like 10%, I think).
Also, I didn't want to blast Jconard, either. I just wanted to make sure that when we point out failures, they are relevant to aviation installations. Of course, there's the old saying "win on Sunday, sell on Monday", so there probably is some relevance here.
Also, it is not my intent to blast the Lycos by pointing out an engine failure that just happened to be catastropic. Again, we should focus on the trends, not the exceptions. Personally, I like Lyco engines. I think the trends are that the Lyco engines have proven to be very reliable with reasonable power-to-weight, I just wish that I could afford one.
BTW, Jconard, thanks for the compliment, I appreciate it. But, alas, I suspect that you are probably referring to Tracy Crook's website (
http://www.rotaryaviation.com/), which I agree, has exceptional information and which I enjoy re-reading on occassion. I would highly reccommend his website to anyone who is interested in alternate engine installations.
Now, back to the original intent of this thread, which is that the new fuel flow numbers for the H6 are now 8.4 GPH at 160kts, .vs. the original 10.1 GPH at 148kts. I think this is great news. Those of us who have followed the Eggenfellner installation for the last few years have been a little disappointed in the numbers. The speeds have been too low, and the weight and fuel flow has been too high, not to mention the price. With the new numbers, the Subie is starting to match the Lyco. Just have to work on that weight issue.
This is what alternate engine developement is all about. If we all gave up after the first installation had a problem or failed to live up to the expectations, we would never have these new choices. I salute Jan's efforts, and thank him for giving the alternate engine movement a little more credibility.
Cheers,
Tracy.