Hopefully we can salvage something useful between meltdowns.
And yet it happened. Gordan's flap horn did indeed break in his first big saito 82 powered Tony flying at the Nats one year. The single 1/16" steel upright broke, and it was not a solder joint problem on this plane.
You mean that the world's foremost self-proclaimed expert on 4-strokes was unaware of something that very famously happened in front of ~100 people at the biggest event in modeling? Another thing we learned from that was that Saito 82s are a lot more powerful than soybean plants, because it really mowed them up!
For those not present, Gordan Delaney's "Tony", powered by a Saito 82 (up from the 72 he used previously, since it fits the same mounts) was flying at the NATs, either on the second day of qualifying or Top 20 day on Circle 4, suddenly started flying level and Gordan started yelling about having no control. It was slowly descending, so he walked it over to the soybean field where it skimmed lower and lower, until it finally dug up about 1/4 lap of soybeans, finally hitting the ground underneath and quitting. The subsequent post-mortem showed the horn upright broken in half, right through the metal. That was a massive surprise to everyone, we had seen some stress cracks and other vibration-related issues on other Saito 72 and 82 airplanes, but nothing where it buzzed up the horn and fatigued it in half in what was something like a few hundred flights. The 82 was fairly new at the time, so not a lot of history.
I think everyone was astonished that you could cause such a failure. I had never even imagined that sort of failure was possible. Everyone starting paying more attention, and then Paul's airplane at the 2004 WC proved the point. I note the original P-51 stayed together, so it's not every time, but often enough you should pay attention.
That's when we all learned that the vibration level on these large 4-strokes was something you had to consider. I haven't about anyone having inordinate vibration issues with the 56 or 52 Surpass.
Bob is a promoter and "enthusiast", not an expert. No problem with that, it's great to have enthusiasm for something. He has been providing questionable technical advice from the instant they "discovered" Saitos. Dirty Dan was very gently making fun of him 25 years ago, when Bob was giving equivalently faulty advice, specifically that what you needed for 4-stroke success was "t-21 style tanks, wood props, and the stock RC carb".
It quickly became apparent that you didn't want to use the carb (random small speed changes) at least not unmodified, the hot setup was a carbon fiber 3-blade prop, and, in particular, you need a *clunk tank*, which is by far the most important bit of information. Ted Fancher had discovered the carb issue 10+ years earlier on his Enya 46 and fixed it by sleeving the carb throat, leading him to design the Citation V around the Enya 46, and then won the 86 NATs using an ST46 and a large amount of lead.
Both the bad advice, and the mocking rebuttal, was published in SN. Look around late 90's-early 2000s, the poop really hit the fan in the middle of 2003, and I think the "get Dan Rutherford" petition was presented and unanimously rejected by the EC at the 2003 NATs. All very well documented.
Somewhat to Bob's credit, having learned something from any number of a more competent experimenters (Brad Walker (mostly via Bill Wilson), the unfortunately late Bob Reeves, and others), he now recommends much more workable solutions and in that, his current advice is sound enough. I note that he hasn't given any input on this issue aside from bad-mouthing me for daring to challenge him. I gather he thinks I am making this all up to "badmouth Saitos" - a topic for which I have little interest aside from my note of caution.
Gordan, Paul, and others discovered these problems, apparently unbeknownst to and with no assistance from the "expert", worked through it despite the early bad advice, and came up with very nice, competitive, and durable airplanes. The 82 is a remarkably powerful and effective stunt engine by 4-stroke standards, and I can see how the ex-ST60 users would like it. It *was* a viable alternative to the all-conquering tuned pipe engines, as Paul showed.
You just have to use a little care and make sure you build them tough enough with some consideration of the vibration issue. Of course, it's now mostly moot, the handwriting is on the wall for all IC engines, David's success notwithstanding. Even the very best tuned pipe engines (PA75, Jett 61, 46VF) are marginally competitive only in the most knowledgeable hands against electric.
Brett
Topic: Saito FA-82B ??? (Read 3707 times)
