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#11
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Perfect loop
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#12
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Perfect loop
More_Flaps wrote:
On Jun 5, 9:40 am, Dudley Henriques wrote: More_Flaps wrote: My aerobatic traing is going very well, I'm having all the fun I thought it should provide. So far I haven't messed up a manouver but I'm nagged by the thought: How can I tell if my loops are perfect circles? At present I go to full power at the vertical phase and over the top but then throttle back a lot as I go vertical again .My wings are level when inverted. I'm pulling 3.5 G as I pull up and level out again. I hit my wake every time but I wonder how much I should throttle back on the descent phase. Should I just try to keep rpm constant? Any ifeas BtB or Dudley or other aerobatic pilot? Cheers Constant speed prop or fixed pitch? Makes a difference. Basically, what you're doing in a loop is controlling energy by varying g and airspeed. The main error pilots make that causes egg shaped loops is in not easing off the g through the high apex. If you don't ease off the g through the top you pull the nose down and spoil the circumference of the maneuver. As for power control, if you are using a constant speed prop, leave it alone and use MP (if at all) to control airspeed. In most trainers like the Decathlon for example, you can just set the airplane up power and prop wise and fly the loop starting with the suggested entry airspeed and vary the g to control the shape of the maneuver without touching the engine controls at all. With a fixed pitch prop, you can increase power on the way up the vertical line (watch the redline) and decrease it on the backside (watch the redline). Be especially watchful for overspeed with the fixed pitch prop. Generally your g profiule sounds about right 3.5 to 4.0 are good profiles for the average trainer using about 140 for your entry. Hitting the wake is a good sign. Sounds like you're doing ok to me. Thanks D, my entry is 140 as you suggest and i'm exiting close to that speed. Its a fixed pitch plane and I am trottling well back on the dive (2000 rpm) and my G at the top is dropping to about 0.5, I'm easing the stick only slightly as I go over. Any other ideas that I can use to evaluate my circularity (or lack thereof?). Cheers Many display pilots (myself included) will develop a set reference plane for vertical maneuvers in the interest of establishing a continuity of visual cues. Basically what this means is that referencing the same side for your visuals can result in the establishment of a continuity reference wise that is a great help with energy management and timing. Eventually,you will be "matching" what the airplane is telling you audibly and through the controls, with the visual cues you are receiving on the horizon and wingtip. My reference sequencing for Loops, Immelmanns , and Cubans was the nose initially in the pull, then the left wingtip through 120 degrees, then the nose again. -- Dudley Henriques |
#13
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Perfect loop
Viperdoc wrote:
However, it's important to remember that the technique needs to vary with the plane and amount of energy going into the loop. From the front in the Decathlon/Citabria, after the initial pull, the back of the lift strut should carve a small circle around the horizon. It is pretty easy to get a sense if the loop is pinched at the top. Unfortunately, without a sight gauge it is somewhat harder (in my opinion) to get a sense of flying over the top and knowing when to ease up on the pull. In the Extra, on the other hand, it generally takes around a 6.5-7G pull to get a good looking loop, since entry speed is generally around 160-180k, and the pull needs to be harder to get the loop at around the same size. Pulling only 3-4g will get a giant loop, but doesn't present well. Because of the greater energy going into the loop in an Extra or equivalent plane, there is less need to ease off and float over the top. If you really want a challenge in energy management, try flying a loop with an entry speed of around 100 or even 80k. It is a great drill in learning how to manage your energy for any given situation. The best way to accurately assess your loop is to get a ground critique, which is also true of any other figure. Without this, you could do the same figure over and over but have it wrong and never know. (at least this was my excuse during competitions). Flying acro is a great flying experience and confidence builder- it will never get boring and will always present new challenges. Just be sure to get good spin recognition and recovery training (for both upright and inverted spins). In this vein, I think most instructors are not a big fan of the Beggs-Mueller method of 1. power off, 2. let go of the stick, and 3. rudder opposite the yaw (not direction of spin). This is the topic for a whole thread in itself. Best of luck and have fun! Respectfully as I know you own and fly an Extra :-) 1. Sensing a loop profile through the float is not especially hard to accomplish without a sight gauge. 2. 6.5 to 7.0 g's even in the Extra is an extremely aggressive loop entry and totally unnecessary for any pilot flying normal aerobatics. A 170 entry speed using 4g's will get you a nice even looking loop in a Pitts S1S, and this is for demonstration. But what you said is interesting. Patty Wagstaff is a friend and flies her Extra in extremely aggressive displays; in fact, some of the best and most aggressive flying I've ever seen. I'll email her tonight and ask her what she uses for loop entry in her displays. I'll be surprised if she uses 6.5 to 7 but I could be wrong. She's EXTREMELY aggressive acrobatically. -- Dudley Henriques |
#14
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Perfect loop
More_Flaps wrote:
How can I tell if my loops are perfect circles? Ask Dudley for technique, but as for the physics: a perfect loop would have a constant acceleration. Just take an accelerometer with you and see how consistent you are (preferably one that can discount the Earth's gravity, and one that you can download the data from, so that you don't have to stare at it while in flight). TheSmokingGnu |
#15
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Perfect loop
"Viperdoc" wrote in
: Let me know what she says- I've spoken with her a number of times, at OSH as well as St. Augustine (I doubt she would remember, but I have the photos). I flew with Phil Knight in some of my intro flights in the Extra, as well as Nicolai Timofeev on several occasions for instruction. Phil was much more aggressive, but he had me pulling on looping maneuvers (full, half, and quarter pulls to vertical) pretty hard, just to where the stick pressure got "soft" at the edge of a stall, in all of the looping maneuvers. With a reasonable pull, this was around 6-7G, as were the pulls to vertical, after doing a bump to load the G. In general, my impression of the same figures in the Extra were around 2-3G more than the Super Decathlon I flew prior to getting the Extra. Klein G, who is on the board of the IAC and frequents this NG, also owns an Extra, and may have a different opinion. In an early contest after getting the Extra, I flew it in sportsman with around the same pulls as with the Decathlon (4.5-4.5G), and the figures were of course a lot bigger due to the higher speed, but didn't present well. It seems that with a high performance monoplane it takes more g to keep the figures tight and present better. However, I'm far from an expert, and now I fly acro for fun- it's just as enjoyable, without the compulsion to make everything perfect. It had started to get to be too much of an obsession, and the fun factor decreased. At this point I figured that if I was looking for stress I could park the plane and go back to work! I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. Oh my God. I'm getting a headache just reading this! I suppose it;s not so bad when you're semi reclined, but still. I've rarely been over five even in square loops. Bertie |
#16
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Perfect loop
Viperdoc wrote:
In an early contest after getting the Extra, I flew it in sportsman with around the same pulls as with the Decathlon (4.5-4.5G), and the figures were of course a lot bigger due to the higher speed, but didn't present well. It seems that with a high performance monoplane it takes more g to keep the figures tight and present better. However, I'm far from an expert, and now I fly acro for fun- it's just as enjoyable, without the compulsion to make everything perfect. It had started to get to be too much of an obsession, and the fun factor decreased. At this point I figured that if I was looking for stress I could park the plane and go back to work! I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. I've never flown competition having mostly done demonstration flying in military prop fighters, the AT6, Decathlons and the Pitts, but I agree totally with you that 3 to 4 wouldn't present well in an Extra routine being judged from the ground. The problem I see with 6+ to 7 is snatch factor (no pun intended :-). At that much positive g into the pull you are really close to alpha crit and could easily slide the airplane deep into drag rise or into accelerated stall from the high aoa delta (rates). In your airplane could be done however with a steady hand :-) Of course having a 10g spread both ways can be helpful :-) I emailed Patty already. Don't know where she is today but she said something a few days ago about showing her horse. She usually answers when she gets a few moments. We work together on a display flying workgroup. She's a great person and is deeply invlved as I am in the human factors involved in display flight safety issues. If I hear back from her I'll post a ping for you. The question as I put it to her was for her entry g profile for a single loop during her demonstration in the 300S. I specified single maneuver realizing her entry speed and g would be higher for a sequence starting with a loop. -- Dudley Henriques |
#17
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Perfect loop
Bertie the Bunyip wrote:
"Viperdoc" wrote in : I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. Oh my God. I'm getting a headache just reading this! I suppose it;s not so bad when you're semi reclined, but still. I've rarely been over five even in square loops. Bertie You and I BOTH get a headache :-)) I don't think I've ever seen anyone work a routine more aggressively than Wags. She works out physically constantly to stay in shape and I know for certain she uses most of the 10g's she has available in her 300S. I'll tell you this much. I flew acro most of my life and I never even came close to doing with an airplane what Patty does in her Extra display routine. MAN..that woman can fly!!! :-)) -- Dudley Henriques |
#18
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Perfect loop
Dudley Henriques wrote in
: Bertie the Bunyip wrote: "Viperdoc" wrote in : I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. Oh my God. I'm getting a headache just reading this! I suppose it;s not so bad when you're semi reclined, but still. I've rarely been over five even in square loops. Bertie You and I BOTH get a headache :-)) I don't think I've ever seen anyone work a routine more aggressively than Wags. She works out physically constantly to stay in shape and I know for certain she uses most of the 10g's she has available in her 300S. I'll tell you this much. I flew acro most of my life and I never even came close to doing with an airplane what Patty does in her Extra display routine. MAN..that woman can fly!!! :-)) Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I would not have cared for that much punishment. i doubt it ver would have appealed, but then again, I never did any aerobatics in an airplane with a semi reclined position though and that should be a huge help. I still can't see how anyone can do 10 Gs regularly even for a short time. in any case, that's over a 300% increase in stall speed! Yipes! Bertie |
#19
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Perfect loop
Bertie the Bunyip wrote:
Dudley Henriques wrote in : Bertie the Bunyip wrote: "Viperdoc" wrote in : I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. Oh my God. I'm getting a headache just reading this! I suppose it;s not so bad when you're semi reclined, but still. I've rarely been over five even in square loops. Bertie You and I BOTH get a headache :-)) I don't think I've ever seen anyone work a routine more aggressively than Wags. She works out physically constantly to stay in shape and I know for certain she uses most of the 10g's she has available in her 300S. I'll tell you this much. I flew acro most of my life and I never even came close to doing with an airplane what Patty does in her Extra display routine. MAN..that woman can fly!!! :-)) Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I would not have cared for that much punishment. i doubt it ver would have appealed, but then again, I never did any aerobatics in an airplane with a semi reclined position though and that should be a huge help. I still can't see how anyone can do 10 Gs regularly even for a short time. in any case, that's over a 300% increase in stall speed! Yipes! Bertie I've pulled high g in the Pitts doing multiple snap entries for example but those, as well as Patty's, are instantaneous with quick release. Most I ever pulled sustained was 9 in the F14 doing some ACM as a "guest" of the Navy and I can tell you that actually hurt! :-) Typical display in the Mustang was 4 or under. -- Dudley Henriques |
#20
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Perfect loop
Dudley Henriques wrote in
: Bertie the Bunyip wrote: Dudley Henriques wrote in : Bertie the Bunyip wrote: "Viperdoc" wrote in : I would be interested in Patty's comments, but my guess is that looking at the tight corners she pulls that they're at least 7G, particularly when entered with a lot of energy. Oh my God. I'm getting a headache just reading this! I suppose it;s not so bad when you're semi reclined, but still. I've rarely been over five even in square loops. Bertie You and I BOTH get a headache :-)) I don't think I've ever seen anyone work a routine more aggressively than Wags. She works out physically constantly to stay in shape and I know for certain she uses most of the 10g's she has available in her 300S. I'll tell you this much. I flew acro most of my life and I never even came close to doing with an airplane what Patty does in her Extra display routine. MAN..that woman can fly!!! :-)) Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I would not have cared for that much punishment. i doubt it ver would have appealed, but then again, I never did any aerobatics in an airplane with a semi reclined position though and that should be a huge help. I still can't see how anyone can do 10 Gs regularly even for a short time. in any case, that's over a 300% increase in stall speed! Yipes! Bertie I've pulled high g in the Pitts doing multiple snap entries for example but those, as well as Patty's, are instantaneous with quick release. Most I ever pulled sustained was 9 in the F14 doing some ACM as a "guest" of the Navy and I can tell you that actually hurt! :-) Typical display in the Mustang was 4 or under. I rarely did more than four displaying and I found five in the Decathlon or Lakes was punishing, but of course neither lasted for long because the speed evaporatd very quickly from those sorts of Gs anyway. I couldn't hardly take more than three outside and avoided doing much of that anyway! Got a good excuse to stay away from them with the new airpane anyway.. Bertie Bertie |
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