I chose , for clarity and simplicty to imbed my response to your post uh...into your post...[8D]
ORIGINAL: STKNRUD
The flight path and the aircraft's inertia ARE material. Anyone who has snapped an aircraft going vertically upward knows. It will not establish a stable downward spin until its inertia is spent, has rolled over and started down. The entry into a spin at stall speed horizontally and level is a whole lot different than going horizontally, vertically upward or downward with lots of inertia. Additionally, the control placements after entry can effect the shape and speed of the rotation. In this case, we have no idea what the pilot was doing with the controls after it rolled right. The ventral fins on the Viper would very likely effect it....they sure do on the Navy's T38C which we found would do an unrecoverable flat spin without them and the strips on the nose cowling (this I have firsthand knowledge of). Also, a stable spin is not usually considered stable until it has rotate vertically downward a minimum of three turns. Some valid points there. MY point was that a snap entry on a down line will look and be the same as one on any other line. The physics of the entry are the same. And for the record, I HAVE done it, a lot, so I do know of which i speak and am not one of the "armchair experts". Competition and airshows both. Pitts and Sukhois. (there was nothing quite as amazing to me as the sight of the nose in my S2-B actually rising above the horizon after power was added to convert a vanilla inverted spin into a flat one. +12g and -8g were the norm during a show in the Suk. The -8g, thankfully, was only temporary during the lump (lomcevak) entry...which I usually entered from a crossed outside snap on a right knife 45 up line). I was also qualled as an I.A.C. judge although I preferred to "call" for judges rather than be one.
I do not think anyone is picking on the pilot (he's been attacked by mutiple "experts" for poor judgement on a number of issues) or the fellow reporting the incident. I hope you remember it was HIS post and request for evaluation of the video ( The pilot, in fact, is not even an RCU member. Recall also that I have been forwarded an email from the pilot and friend of his, who upon exam of the wreckage have determined that there was indeed a radio issue which affected the flaps specifically. Of course, Chad has taken it upon himself now to brand the man a liar who is "full of crap", so yes...the pilot IS being attacked.) and I think everyone's opinion of the video is as valid as yours. No doubt it could have been a control surface problem, but in the absence of more post-accident specifics to the contrary, we have a dirty heavy (Really? How heavy was it? What was his fuel state? Smoke oil state? How long had he been in the air before the loop? How much smoke had he used? Were you there? Did you help carry away the wreckage perhaps and see what was left in the tanks? Is it possible that you have presented your own assumption as if it were a fact The assumtion is understandable, but I'm sure you'll agree upon further reflection that you have no knowledge of the weight and that "heavy" is not a fact in the vid or elsewhere.) ?airplane with a very high angle of attack and wing loading with a pilot possibility pulling back harder than normal to secure a gear (unless he just decided to do a dirty loop seconds after the nose gear went down). There was no evidence of any control issue prior to the abrupt roll to the right. (neither was there evidence that he was a poor pilot who did not have the talent or experience to successfully complete the manuver, but many here are more than willing to assume that was the case none the less. In other words, it is ASSUMED by many that the a/c was normal and the pilot malfunctioned. Why not assume that the pilot was funcioning normally and the a/c malfunctioned? There is more than a small amount of evidence that the airplane broke, but that is IGNORED my most, even as the continue to blame pilot error on the basis that his thumbs were "plainly" not correctly calibrated. Note that the a/c barreled right. it did not snap right.) Unless he reports to us some more specifics about a broken linkage or strip gear (Actually, please re-read the thread more carefully. He HAS reported, to me, and through his friend and fellow experienced Viper owner, that the flap function of the radio is dorked. Again, the owner is not an RCU member. And again, I'm sure that the friend who sent me the email will continue to be villified as a "full of crap" liar. I don't know either of the guys, but I have no reason to doubt their word. Neither does anyone else here, but those who seem to be so personally invested in being "right" will villify them anyway, I'm sure) , I have to stick with what appears, in my opinion, (That's cool. I simply wish everyone who's posted an opinion had the humility to label it as an opinion, that they not evidence contrary to their opinion simply because it is...contrary) the probably cause which includes more the the shape of the rotation. (the flight path, or "shape of the rotation", as you put it, is IMO one of the strongest point against the snap/spin theory. That's not the flight path of a spinning a/c, it's the flight path of a spiraling/barreling one, which demonstrates that the inside wing was not stalled...IMO) If anyone wants to video his Viper doing the exact same maneuver and post it here that might give us some more info too.
The attitude or direction of the flight path at entry are immaterial, as is the flight path once the spin is established, because the laws of aerodynamics don't care which way the jet is flying. A snap on a down line looks the same as one on an up line or a horizontal one.
Regards, Don.