Intakes and Internet myths, Part 2.


On October 10th 2012, I wrote the first part of this. The story was formed around showing builders that the style of intake manifold that we have used for years on Corvair flight engines is actually a very well engineered design that appears over and over again on purpose designed aircraft engines built by large Aircraft industry giants like Alison on the 1710 V-12. I was looking for a particular photo on our main website and came across this photo that I took at the Pioneer Airport side of Oshkosh in 2008. Get a good look at this engine and see that the intake is a systematic copy of the one we use on a Corvair.

Above is a 440 cid air cooled Ranger inline six  It is a 200 hp engine of WWII vintage. They were on Fairchild 24s, PT-19s, Grumman Widgeons and a number of other classics.  Note how the feed pipe for each group of three cylinders is offset just like a Corvair head. The center part of the manifold is a Tee section to hold an updraft one barrel carb, just like we use on the majority of flying Corvairs. If you look at the system, the proportions of the components are much the same as we use on the Corvair.

I dug out the original information in part one because an internet ‘expert’ with the named “Toolbuilder” was pontificating that he knew how to get a 20% increase in output on the Corvairs heads by using individual runners, Complete BS, as demonstrated by the dyno runs I pictured in part one. The next time an armchair expert tells you that the Corvair’s head is not well designed, or has poor fuel distribution, save time and tell him he is a genius, then walk away knowing that many aircraft have the exact same design as the Corvair.

You may wonder what kind of group of people would tolerate a person like “Toolbuilder” who goes around making baseless claims about aircraft systems he has never seen in person, far less has any understanding of. Wonder no further. The guy is a fixture on the Van’s Airforce website. The format of this webpage has a management section that tells me how many people a day read it, and it has a section to show how many people came from a hyperlink on another site. For example, in the 24 hours between 7pm sunday and 7pm tonight (It works on a 24hr zulu time clock) we had 932 readers. 66 of them first went to our page and used the ‘click here’ hyperlink to arrive here. Those are about average for a Sunday/Monday. What stuck out was that 40 people came to the site from the Vans Airforce discussion groups yesterday.

I went there and found a lot of the discussion was started about A twin-engine Corvair powered airframe that started out life as an RV-6A, being built by a friend of ours. I fully understand that there are 20,000 RV builders so it’s not safe to generalize about them just because 75% of the comments about the twin project were some of the saddest knee-jerk/internet expert/ drama queen comments I have read in a long time, but that’s a pretty high percentage for people who are alleged to understand what EXPERIMENTAL aviation is about. As you may have guessed, Mr “ToolBuilder” was right in there. Two or three people had something positive to say, many of the others were operating at the hyper-dramatic doom speculation level I refer to as “Mother-in-law on Methamphetamines.”

As I read some of the comments, one of the things that came to mind is that Fans of the RV designs are woefully ignorant of the origins of their own airplane company. (The RV-1 was a modified Stitts design. If Ray Stitts took the attitude of the people on the Vans airforce site, there would be no RV anything today.) Secondly, I have heard RV fans say things about the position of Dick Van Grunsven countless times as if each of them were his paid press secretary. Mr VanGrunsven is a publicly reserved guy, but I have sat through a number of industry meetings with him. At this last Oshkosh, I was one of 16 people who went to a 4 hour kit industry think tank meeting. Mr, VanGrunsven was the Chairman and spoke with frankness about many issues. Know what? After listening to him in this setting, I will tell you that 50% of the things his followers say don’t come close to positions he actually holds. It is oddly Ironic that I have much better insight to the perspectives of the man than the great majority of the people making endless posts on his official webpage, but a small detail like that never stopped an internet personality with a silly name.-ww


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