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#1
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My Seneca is. So I don't use full flaps unless there is some aft weight.
Without anything in the back, the cg is almost at the front limit. Just "two notches". To flare nice with full flaps invites a tail stall. Very common and I was taught, that is why there is the abundance of nose gear collapses in the type. Because the pounding the nose gear is given. Rolling in nose up trim makes things easier. It is just done when over the numbers, entering a flare. John Michelle P wrote: Jim Macklin wrote: Be careful with using the electric trim to flare. Assuming that the airplane is properly loaded with the CG within the range, the elevator forces required between an approach speed of 1.3 Vso and the flare should be slight. Do a W&B for your landing configuration, be sure to check for an items stowed in a forward baggage area and for fuel. The problem that WILL happen is at some point you will gave to go-around, that means you will need a hand on the power and you will REALLY need two hands on the elevator because the electric trim isn't fast enough, you will have a sudden need to hold the nose down, will loose A/S, perhaps even stall, then the real bad thing can happen, en engine failure, Vmc and spin at 100 AGL. Do some exercise with weights, it is safer. there are some planes that are just nose heavy. |
#2
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The Visitor wrote:
To flare nice with full flaps invites a tail stall. Not likely. You will lose elevator authority, but the AOA gets smaller as the tail moves down. why there is the abundance of nose gear collapses in the type. Actually, there is an AD out on the Seneca nose gear. The collapses are generally due to misrigging of the airplane. Friend of mine has a nosewheel collapse after a full stall, nose high landing. |
#3
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No, and with full flaps it pull an greater aoa for the same
authority(down force). It stalls. And the nose can drop real hard. As the stab moves into ground effect the aoa increases also. The Cessna Cardinal had this problem, which later got addressed with slots in the stabilator. Greg Esres wrote: The Visitor wrote: To flare nice with full flaps invites a tail stall. Not likely. You will lose elevator authority, but the AOA gets smaller as the tail moves down. why there is the abundance of nose gear collapses in the type. Actually, there is an AD out on the Seneca nose gear. The collapses are generally due to misrigging of the airplane. Friend of mine has a nosewheel collapse after a full stall, nose high landing. Generally? I'm sorry about your friend and a misrigged gear on anything is a hazard. And the pa34 nose gear (like any) can be mis-rigged.But the seneca nose gears take a pounding because of the way they are flown. It leads to failures. John |
#4
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By way of an addition....
if somebody is in the back it is very easy to rotate for a nice flare without getting close to a tail stall. Even with full flaps. Tlhere is probably only one knot difference in stall speed between two notches and three(full). Fuel and row one passengers only, the cg is very near it's forward limit. A local flying school that also rents out it's Seneca has some weight strapped down in the back area, I think 75 pounds. I think they had three collapses over the last 15 years and none were due to mis-rigging. And it is checked every 50 hours and also they hold an stc for putting a window in so it can be inspected through the nose baggage area each flight. The Visitor wrote: No, and with full flaps it pull an greater aoa for the same authority(down force). It stalls. And the nose can drop real hard. As the stab moves into ground effect the aoa increases also. The Cessna Cardinal had this problem, which later got addressed with slots in the stabilator. Greg Esres wrote: The Visitor wrote: To flare nice with full flaps invites a tail stall. Not likely. You will lose elevator authority, but the AOA gets smaller as the tail moves down. why there is the abundance of nose gear collapses in the type. Actually, there is an AD out on the Seneca nose gear. The collapses are generally due to misrigging of the airplane. Friend of mine has a nosewheel collapse after a full stall, nose high landing. Generally? I'm sorry about your friend and a misrigged gear on anything is a hazard. And the pa34 nose gear (like any) can be mis-rigged.But the seneca nose gears take a pounding because of the way they are flown. It leads to failures. John |
#5
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I think they had three collapses over the last 15 years and none
were due to mis-rigging. And how do you know? Our mechanics said the same thing, but it struck me as a cover-your-ass sort of defense. And it is checked every 50 hours and also they hold an stc for putting a window in so it can be inspected through the nose baggage area each flight. They've had the window in for 15 years? The problem only came to light in the past few years. Our mechanics also put in a window. |
#6
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Oh I know. I can imagine how it strikes you, but that is it. I think
they also hold some stc for some kind of mod in there also. Greg Esres wrote: I think they had three collapses over the last 15 years and none were due to mis-rigging. And how do you know? Our mechanics said the same thing, but it struck me as a cover-your-ass sort of defense. And it is checked every 50 hours and also they hold an stc for putting a window in so it can be inspected through the nose baggage area each flight. They've had the window in for 15 years? The problem only came to light in the past few years. Our mechanics also put in a window. |
#7
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This is from "Cessna Wings for the World", by William D. Thompson,
regarding the C-177: ==================================snip========== ============= The pitch-down motion in flaps-down sideslips was a more serious problem, however. Production test pilots became aware of a more noticeable waviness in some of the leading-edges of the wing, and occasionally, a 2-foot length of paint overspray that caused wing- dropping tendencies at the stall. This had to be corrected by applying body filler material on the leading-edge or rubbing compound to remove the almost invisible overspray. There was also questionable uniformity of the stabilators, giving as much as 15-mph deviations in minimum trim speeds. On some airplanes they reworked or actually replaced the stabilator with some improvement. This led to the decision to incorporate slots into the stabilators' leading edges so that they could tolerate a steeper downflow of air without stalling the under-surface of the stabilator. This solved the problem, and a fleetwide "Cardinal Rule" retrofit was planned at no cost to the customer. In the meantime, a service bulletin called for a temporary installation of a simple sheet metal plate that would limit the maximum flap deflection to 15 degrees. We were paying the price for these thin skins. ==================================snip========== ============= So this was more than just a stabilator stalling; it had more to do with production problems than an inherent design problem. A tail- stalling airplane wouldn't pass certification tests. |
#8
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Greg Esres wrote in news:1191895718.877577.245080@
50g2000hsm.googlegroups.com: This is from "Cessna Wings for the World", by William D. Thompson, regarding the C-177: ==================================snip========== ============= The pitch-down motion in flaps-down sideslips was a more serious problem, however. Production test pilots became aware of a more noticeable waviness in some of the leading-edges of the wing, and occasionally, a 2-foot length of paint overspray that caused wing- dropping tendencies at the stall. This had to be corrected by applying body filler material on the leading-edge or rubbing compound to remove the almost invisible overspray. I~mpossible. how could a bit of paint cause a los of lift when th ewing shape is only htere for streamlining? Bertie |
#9
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To borrow your phrase, it strikes me more as a cya thing because it did
get out to the market place. Greg Esres wrote: This is from "Cessna Wings for the World", by William D. Thompson, regarding the C-177: ==================================snip========== ============= The pitch-down motion in flaps-down sideslips was a more serious problem, however. Production test pilots became aware of a more noticeable waviness in some of the leading-edges of the wing, and occasionally, a 2-foot length of paint overspray that caused wing- dropping tendencies at the stall. This had to be corrected by applying body filler material on the leading-edge or rubbing compound to remove the almost invisible overspray. There was also questionable uniformity of the stabilators, giving as much as 15-mph deviations in minimum trim speeds. On some airplanes they reworked or actually replaced the stabilator with some improvement. This led to the decision to incorporate slots into the stabilators' leading edges so that they could tolerate a steeper downflow of air without stalling the under-surface of the stabilator. This solved the problem, and a fleetwide "Cardinal Rule" retrofit was planned at no cost to the customer. In the meantime, a service bulletin called for a temporary installation of a simple sheet metal plate that would limit the maximum flap deflection to 15 degrees. We were paying the price for these thin skins. ==================================snip========== ============= So this was more than just a stabilator stalling; it had more to do with production problems than an inherent design problem. A tail- stalling airplane wouldn't pass certification tests. |
#10
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No, and with full flaps it pull an greater aoa for the same
authority(down force). It stalls. And the nose can drop real hard. As the stab moves into ground effect the aoa increases also. Sorry, I was thinking of a horizontal stabilizer/elevator combo. Still, the lift coefficient of the horizontal tail most likely doesn't get near Clmax. I regularly make full stall landings with the Seneca using 40 degree flaps.The tail doesn't stall. If the nose drops, it's a physical strength issue. But the seneca nose gears take a pounding because of the way they are flown. It leads to failures. The British did a very elaborate analysis of the nose gear on the Seneca and didn't think that was a factor. The gear is designed to withstand vertical loads. It's front to back loads that are a problem. |
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