If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#51
|
|||
|
|||
barrel roll in 172
"Matt Whiting" wrote in message ... Big John wrote: Andrey As has been said in all the posts, the short answer is NO. 172 is not certified to do barrel rolls. However I can barrel roll a 172 only pulling 1 G which puts no more load on airframe than straight and level flight. I have thousands of hours to back up my statement. Your thousands of hours aside, this is simply an incorrect statement. A barrel roll requires flying a loop and you can't fly a loop at 1 G. It sounds like you are describing an aileron roll. Matt I think what John meant was that once you start the roll by blending in aileron, you can "adjust" in pitch to any g you want. Naturally, in the initial pull to the roll initiation point, (assuming a straight pull with a rolloff into the barrel roll, you will be pulling more than +1g. A lot of people have trouble visualizing this "split" between the roll entry and the roll itself and naturally include the pulling g into the roll to arrive at a higher g required to do a barrel roll. The truth of it is, once that aileron is blended in and the airplane is rolling through 3 dimensional space, you can actually unload it all the way down to 0 g and improve the roll rate, which is exactly the way many fighter pilots do these 3 dimensional rolls in an ACM environment. Some fighters like the F100 and the F4 (at certain aoa and airspeeds) can be barreled (any roll done in both the vertical and horizontal maneuvering planes using all three dimensions is a barrel roll :-)) using rudder alone. It must be assumed of course that positive g must be re-aquired on the back side during the recovery back to level flight. But make no mistake, you can play around quite a bit with the g during the area of the roll between the two knife edges by playing the pitch you are using during that phase of the roll :-)) I've done barrel rolls deep in the left side of the envelope using hard inside rudder in high performance jets that you would swear were snap rolls!! :-)) Dudley Henriques |
#52
|
|||
|
|||
barrel roll in 172
What does "dished out" mean?
Matt, this and your previous post show you do not have a broad knowledge of the world of aerobatics. Please do not dispute those that do. Your condescending tone is most inappropriate. What does "dished out" mean? I've never heard the term. My question is neutral. Jose -- The monkey turns the crank and thinks he's making the music. for Email, make the obvious change in the address. |
#53
|
|||
|
|||
barrel roll in 172
Did a Boeing Test Pilot barrel barrel roll a 707 over the boat races on Lake Washington without any damage to aircraft. YES. No, it wasn't a barrel roll, it was an aileron roll. (At least this is what I've been told, and it makes a lot of sense.) Someone correct me if I'm wrong, but isn't an aileron roll a negative 1 G maneuver? You spin on an axis, through the plane's center of gravity. For an instant, the pilot is upside down, hanging by the belt. Mr. Boeing would not be pleased if all of the gas and oil was on the top of the tank, away from the fuel and oil pickups. The 707 roll was indeed a barrel roll. Check it out on Jay's webpage. -- Jim in NC |
#54
|
|||
|
|||
barrel roll in 172
Dudley Henriques wrote
I've done barrel rolls deep in the left side of the envelope using hard inside rudder in high performance jets that you would swear were snap rolls!! :-)) Dudley, what source do you use for your definition of a "barrel roll"? Bob Moore |
#55
|
|||
|
|||
barrel roll in 172
"Bob Moore" wrote in message . 122... Dudley Henriques wrote I've done barrel rolls deep in the left side of the envelope using hard inside rudder in high performance jets that you would swear were snap rolls!! :-)) Dudley, what source do you use for your definition of a "barrel roll"? Bob Moore Well, after teaching them and doing them for fifty years, I guess I could use myself as a source. I know of at least one major aviation magazine and one major book on airshow safety who have used me as an aerobatic source anyway :-) That pushed aside for obvious reasons of propriety, your IAC source is fine, as is your good Navy training . Remember Bob; the military usually teaches barrel rolls in the classic format for primary, which is as a precision maneuver using specific points of reference to be obtained during each segment of the maneuver. You usually don't get into variations of 3 dimensional maneuvering until lead in basic BFM and ACM. I also probably taught barrel rolls to primary aerobatic students the same way you learned them in the Navy. Advanced maneuvering is another matter. Just remember when discussing barrel rolls; there are only two ways to move an airplane through three dimensional space. You can maneuver it using a two dimensional maneuver through three dimensional space, or you can maneuver it using a three dimensional maneuver through three dimensional space...and that three dimensional maneuver is a barrel roll, no matter how tight or how loosely you fly through the roll. Any roll, no matter how it's done, that moves the airplane "around that barrel" is a barrel roll. If you want to do it using the points system with the nose pointed exactly 90 degrees to the entry heading at the inverted point, that's fine. That's a barrel roll. If you want to pitch into the vertical line, and roll off that lineputting the pole in the left or right corner of the cockpit winding it through like a cork screw, that's also a barrel roll. As long as you have three dimensions in play during the roll, its a barrel roll. I seem to remember the Navy defining barrel rolls in the J Stage of training in the F9F-8 Cougar as a shallow dive at about 95% to 350kts; level off and trim; then roll the airplane around a point 45 degrees off the nose to either side; initial acelleration to about 3g's; the nose should reach a point about 45 degrees above the horizon at the 90 degree point; the roll rate was adjusted to achieve a 90 degree heading change at the 180 degree point inverted; ; you looked for about 180 to 200 kts at the top inverted where you were looking at about 1+g if you did it right; as the nose came through the back side, you adjusted the roll rate to nail level flight again at your initial entry speed of 350kts. You would play the g from the initial 3 during the entry down to the 1 at the top, then play back in the 3 during the recovery back to level flight. This is a good way to teach a barrel roll, adjusting the speed and roll rate a bit of course for something like the SNJ :-)) But all this dosen't change the fact that a barrel roll can be done much tighter than this and doing it that way dosen't change the fact that you are doing a barrel roll :-)) Dudley |
#56
|
|||
|
|||
barrel roll in 172
john smith wrote:
In article , Matt Whiting wrote: Dudley Henriques wrote: Scotty McCray flew a Schweizer 2-22 EK for his demonstrations. We appeared at the same shows many many times and I knew him quite well. The 2-22 wasn't exactly the "cleanest" glider in the world by today's standards. Scotty was an absolute master at energy control. His technique for energy management was in my opinion the best I've ever seen done in an unpowered aircraft. I think I watched Scotty perform hundreds of barrel rolls in the 2-22 and never once did I see him dish it out of a roll. Strangely enough, it was the addition of horsepower to his aerobatics that killed him down in Brazil in 73, when the Decathlon he dished out of a low altitude roll. One of the nicest and finest guys I knew in aviation. Dudley Henriques What does "dished out" mean? Matt, this and your previous post show you do not have a broad knowledge of the world of aerobatics. Please do not dispute those that do. Your condescending tone is most inappropriate. I've never claimed broad knowledge of aerobatics. I do have a pretty good grasp of physics though and the comment about the barrel roll violates physics (as well as published descriptions of the forces incurred in executing a barrel roll). Matt |
#57
|
|||
|
|||
barrel roll in 172
Dudley Henriques wrote:
"Matt Whiting" wrote in message ... Dudley Henriques wrote: Scotty McCray flew a Schweizer 2-22 EK for his demonstrations. We appeared at the same shows many many times and I knew him quite well. The 2-22 wasn't exactly the "cleanest" glider in the world by today's standards. Scotty was an absolute master at energy control. His technique for energy management was in my opinion the best I've ever seen done in an unpowered aircraft. I think I watched Scotty perform hundreds of barrel rolls in the 2-22 and never once did I see him dish it out of a roll. Strangely enough, it was the addition of horsepower to his aerobatics that killed him down in Brazil in 73, when the Decathlon he dished out of a low altitude roll. One of the nicest and finest guys I knew in aviation. Dudley Henriques What does "dished out" mean? Matt When you do a roll, the second half of the roll requires changing rudder and blending stick in elevator and aileron. If you are late on the rudder change, or late on the elevator blending out from forward elevator to back elevator, its possible to allow the airplane to change from rolling on its longitudinal axis to an arc through the back side recovery. Basically what happens is that you "slide" off the roll axis and widen the roll nose low through the arc. In effect, you are changing the aircraft's roll axis from a controlled slow roll to an aileron roll format, which is primarily aileron and allows the nose to arc naturally during the roll unlike the slow roll format where the airplane is "flown" through the entire roll from the roll initiation at the apex of the pull on the airplane's longitudinal axis. We call this coming in late and allowing this to happen on the back side "dishing out" of the roll. Allowing this to happen is one of the major killers, if not THE major killer of pilots doing low altitude roll maneuvers. Not allowing dishout on a roll is so critical in low altitude demonstration work that when I practiced slow rolls for demonstration purposes, I would set the airplane on the roll apex at it's inverted nose attitude while right side up after a pull to the set point from a point where the altimeter needle was covering the 0 on the altimeter, then roll the airplane from the initiation point returning the needle to recover the 0 again as level flight was achieved again on recovery. Any deviation from that standard was considered a blown roll, and the entire practice session would have to be re-flown. Dudley Henriques I think I got it, but this is a case where a graphic would be worth a thousand words! :-) Do you know of any web graphics that illustrate this error? Matt |
#58
|
|||
|
|||
barrel roll in 172
Peter R. wrote:
Matt Whiting wrote: Your thousands of hours aside, this is simply an incorrect statement. A barrel roll requires flying a loop and you can't fly a loop at 1 G. It sounds like you are describing an aileron roll. The descriptions from the aerobatic website, it appears, disagree with your understanding of a barrel roll and aileron roll: http://www.iac.org/begin/figures.html#Aileron%20Rolls How so? It says that you pull from 0.5g at the minimum to between 2.5 and 3g at the maximum during a barrel roll. That is far different than having a constant 1g acceleration as the OP said. Matt |
#59
|
|||
|
|||
barrel roll in 172
Dudley Henriques wrote
I seem to remember the Navy defining barrel rolls in the J Stage of training in the F9F-8 Cougar as a shallow dive at about 95% to 350kts; level off and trim; then roll the airplane around a point 45 degrees off the nose to either side; initial acelleration to about 3g's; the nose should reach a point about 45 degrees above the horizon at the 90 degree point; the roll rate was adjusted to achieve a 90 degree heading change at the 180 degree point inverted; ; you looked for about 180 to 200 kts at the top inverted where you were looking at about 1+g if you did it right; as the nose came through the back side, you adjusted the roll rate to nail level flight again at your initial entry speed of 350kts. You would play the g from the initial 3 during the entry down to the 1 at the top, then play back in the 3 during the recovery back to level flight. And that seems to be the way that the IAC defines a barrel roll at the posted reference. They and the Navy make no reference for doing them any other way. Neither does William Kernsher who has an oustanding reputation for instructing and writing books on aerobatic instruction. But all this dosen't change the fact that a barrel roll can be done much tighter than this and doing it that way dosen't change the fact that you are doing a barrel roll :-)) Just point me to the references that make this point. :-) Bob Moore |
#60
|
|||
|
|||
barrel roll in 172
Stefan
I'm glad your the expert. I used to do half of a barrel roll at one G and give to student under the hood upside down to recover. Bird of course was acro rated but student couldn't tell we had rolled inverted and we were pulling 1 G positive when handed over. Big John ````````````````````````````````` On Thu, 20 Jul 2006 21:35:26 +0200, Stefan wrote: Big John schrieb: However I can barrel roll a 172 only pulling 1 G which puts no more load on airframe than straight and level flight. I have thousands of hours to back up my statement. No, you can't do a barrel roll without pulling more than 1g. Did a Boeing Test Pilot barrel barrel roll a 707 over the boat races on Lake Washington without any damage to aircraft. YES. No, it wasn't a barrel roll, it was an aileron roll. (At least this is what I've been told, and it makes a lot of sense.) Stefan |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
rec.aviation.aerobatics FAQ | Dr. Guenther Eichhorn | Aerobatics | 0 | October 1st 04 07:27 AM |
rec.aviation.aerobatics FAQ | Dr. Guenther Eichhorn | Aerobatics | 0 | July 1st 04 08:27 AM |
rec.aviation.aerobatics FAQ | Dr. Guenther Eichhorn | Aerobatics | 0 | June 1st 04 08:27 AM |
rec.aviation.aerobatics FAQ | Dr. Guenther Eichhorn | Aerobatics | 0 | May 1st 04 08:27 AM |
rec.aviation.aerobatics FAQ | Dr. Guenther Eichhorn | Aerobatics | 0 | April 1st 04 08:27 AM |