Aerobatic aircraft options?

Discussion in 'Aerobatics' started by QR30, Jan 5, 2022.

  1. kyleb

    kyleb Final Approach PoA Supporter

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    You're right. But if you're trying to maximize roll rate, it'll probably boos the numbers a bit.
     
  2. Ed Haywood

    Ed Haywood Line Up and Wait

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    I'm trying to do all the right inputs at the right times, but of course that is easier said than done. It is hard to appreciate from a video the physical forces applied to your body, and not just the obvious G force. In a slow roll you go from upright to laying on your side to hanging upside down to laying on your other side. You are strapped in at the hips, so you are straining against gravity to keep your torso and shoulders centered. All the while you are arm wrestling the stick to keep full aileron deflection in, while trying to push and pull the stick and put in rudder at the right times. There's just a lot going on in 3 dimensions.

    Oh BTW I have a crappy 5 point factory harness without a ratchet, so until I upgrade to a Hooker harness I am also getting slung around due to the slack in the belts.

    I've never flown a super space age monoplane like an Extra with a 360 roll rate, but my impression is that all that happens so fast that you don't feel it so much. I don't believe you need much top rudder on knife edge or forward stick thru inverted, because you just don't spend enough time to lose altitude.

    With an airplane like a Super D, it takes a lot of top rudder on knife edge and a lot of forward stick while inverted to avoid losing altitude. And back to the physical forces, a roll takes me 6-8 seconds, so I am spending 3-4 seconds hanging upside down or at a weird angle, all while trying to keep the stick deflected, push the stick forward and then pull it back, and transition off rudder with my right foot and then add rudder with my left foot.

    Oh what the hell, here is my Sportsman Sequence today. It is VERY rough, but I've only been back in the saddle for 4 months after a 14 year break.



    sportsman 2022.PNG
     
    Last edited: Jan 12, 2022
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  3. kyleb

    kyleb Final Approach PoA Supporter

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    Yeah, that roll you started at 1:52 took 5-6 seconds, so that makes it 60-70 degrees per second on average. @nauga could tell you the sho-nuff correct way to measure roll rate, which I'd bet has you doing something like a 450 degree roll and not counting the time to roll the first or last 45 degrees. That way, the measurement only represents the fully developed roll rate.
     
  4. whifferdill

    whifferdill Line Up and Wait

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    Hey Ed, that was pretty solid! I see you are doing the classic Decathlon pilot hand hold of the cabane tube haha. Anyway this is easy stuff to clean up with a little help from the ground. Few notes, which you probably see as well -

    Consider the wing wags Figure 0 and be sure to do them on practice flights so you don't forget them on a real contest flight.

    On the spin entry, try getting the nose up at a slightly faster rate as you slow to the stall (climbing very slightly is perfect), and hold a slight bit of left rudder pressure before the stall to clean up the spin entry. Here, the nose dropped a good bit before the airplane yawed and rolled into the spin. You want movement on all three axes to occur simultaneously. Decathlons are notorious for mushing into the spin unless you're careful to control it.

    A little pendulum stopping the hammer, decent looking hammer though.

    On the Immelman it looks like you're dishing to the right during the last half of the 1/2 roll. Be sure to start the roll from inverted with opposite (right) rudder until you've passed about 30 degrees of roll when you start to transition to top (left) rudder. If you don't, you'll go off heading on the first half of the roll. Looks like you might be ending up back on your final upright heading, but there's a very large swing of the nose to the right through the last quarter of the roll. Can't tell if you're off heading and correcting, or if you need more left rudder after passing through knife edge and finish the roll. You actually have to increase your left rudder input after passing through knife edge, since you have to hold the nose up AND counter adverse yaw as the airplane becomes positively loaded again.

    On the Split S, don't pull the nose down quite so sharply. This will set an initial small radius that will be impossible to maintain as speed builds. Accelerate the pitch more progressively, but you still of course need to get G on the airplane relatively quickly to control your airspeed. Pull some power to control your entry airspeed if needed, but get the power back in before you begin the figure.

    Looks like you could hold your humpty upline a beat longer and fly over the top with slightly less airspeed, but again ground critiquing/coaching rules. Good luck, hope you can make a Spring contest. Eric
     
  5. Ed Haywood

    Ed Haywood Line Up and Wait

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    Fantastic tips, thanks. This is the first time I have flown with a camera, and it definitely helps see things I missed in the air. You hit on a few of my known weaknesses, so now I have a practice plan.

    The Immelman into a Split S was a point of stress for me. The first few times I tried it, I was too fast going into the S and pushing Vne at the bottom. That got me pulling too abruptly to load it up. On this video, I actually did a good job keeping the nose up during both of the half rolls, the result being I finished the S at the top of the green arc. I'll smooth out the initial pull a bit and tighten it up on the bottom quarter, and accept more speed at the end, which will improve the vertical on the humpty.

    At as minimum I will fly Sebring, which is only 30 minutes away. If work and contest schedules jibe, I hope to hit Ocala and Rome.
     
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  6. kyleb

    kyleb Final Approach PoA Supporter

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    Shoot me a note when you come to Rome. It is a hop, skip, and jump from my home field.
     
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  7. somorris

    somorris Pattern Altitude

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    Thanks for posting the video and sequence, Ed, despite your being a little hesitant. Not that my opinion counts like Wifferdill's does, but I thought it looked pretty good. I was really surprised the first time (as a totally inexperienced pilot) I watched a practice session and could see mistakes being made. I second the suggestion to get somebody watching from the ground.

    Good luck at Sebring!
     
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  8. QR30

    QR30 Filing Flight Plan

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    Thanks for posting looked like alot of fun!
     
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  9. djpacro

    djpacro Pre-takeoff checklist

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    I flew that for the roll rate challenge on Facebook a while back. You can see the technique I used and airspeed. I have attached the roll rate summary chart for info.

    Seems that my old '79 Standard Decathlon (wood spar wings) is a bit slower

    SAE TP 700222 Loading Conditions Measured During Aerobatic Maneuvers (by NASA in conjunction with the Decathlon factory) shows 1.7 rad/sec or 97 deg/sec for aileron rolls at 117 kts.

    70222rollrate.png

    108632267_10158539563841665_705541927262151833_o.jpg
     
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  10. Grum.Man

    Grum.Man En-Route

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    I timed the Venture at about 100 degrees/sec. It feels more crisp than the roll rate suggest. From the videos I've seen I should be satisfied with my S1C but I do have some sparcraft S wings I can put on eventually.
     
  11. Ed Haywood

    Ed Haywood Line Up and Wait

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    Looks like you have that camera mounted on your head? I can tell by the way it slings you around sideways. That's what I was trying to describe above.

    I previously had an older Decathlon 150 with spades. Found a pair of used Olin Pash spades recently, but the STC only covers Citabrias so I passed on them.