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Best angle proceedure

The Kid

FOUNDER
Thompson Falls
So if I really need to climb at best angle, to avoid colliding with some trees, the book says climb at 45 indicated with full flaps as I remember. I have the Pstol flaps. The airspeed indicator isn't really your airspeed for various reasons but maybe the 45 mph took that into consideration. Would it be best to climb with full flaps and full power, just on the edge of a stall, for absolute best angle performance to clear those deadly trees? Of course if the engine hiccupped or you stalled ; that wouldn't be good but that isn't what I am looking for. Just configuration for absolute best angle of climb.
 
Very few aicraft have best angle with full flaps. I suspect that P-stol might be different from regular Cub flaps in vertical performance. Surely they had to give you a supplemental AFM?

A stock 160 Supercub is indeed impressive at full flaps - the deck angle is around 45 degrees. It is that extreme deck angle that enables obstacle clearance. I have only done it a couple times close to the ground, because I am sure an engine failure would not be recoverable - it is actually scary.

The Cessna 180 is done at flaps 15 as I recall. Also a scary deck angle. Only did it once.
 
As Bob mentioned, is there a supplemental AFM? Or do they do like VG's and others have, offer no remarkable change to factory established flight data? The manufacturer does promote better landing performance.

Gary
 
Here you go - no change. Man, that is a lot of bucks for no change - I am a believer in slotted flaps, and cannot believe these things do not give at least a five knot change in approach speed.

https://documents.alaskagearcompany.com/docs/PSTOL-Flight-Manual-Supplement.pdf

My list of changes if I were a wealthy Super Cub buyer - Dakota slotted wings, P-stol flaps, X-brace, Grove masters and discs, 160 Lyc, and Hooker harnesses - oh, yeah, and a GTR-200 and a mounted Garmin 496. Nothing else other than good paint and upholstery - maybe wingtip strobes.
 
And a bonus...no weight and balance change. Anybody confirm that? My float pond neighbor mentioned after he spent $10K+ he should have just moved the flaps into the fuselage. He has owned many and has more Cub time than any of us nearby. But yes, others here and there like the flaps and say they land slower.

Gary
 
Climb angle is solely dependent on excess thrust. Drag opposes thrust. Flaps = more drag.

Flaps do affect the departure/unstick point which affects where your climb angle begins. In general more flaps clear close in/low obstacles better and less flaps or no flaps provide greater margin for more distant and higher obstacles. What defines close or distant is aircraft dependent. Our POHs in cubs are written for aircraft that often dont resemble the cubs we are flying so who knows what the real Vx for your plane is. As stated above there are ways to calculate it for your plane. I would test both clean and configured with half flaps to get correct speeds for both.


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Here you go - no change. Man, that is a lot of bucks for no change - I am a believer in slotted flaps, and cannot believe these things do not give at least a five knot change in approach speed.

https://documents.alaskagearcompany.com/docs/PSTOL-Flight-Manual-Supplement.pdf

My list of changes if I were a wealthy Super Cub buyer - Dakota slotted wings, P-stol flaps, X-brace, Grove masters and discs, 160 Lyc, and Hooker harnesses - oh, yeah, and a GTR-200 and a mounted Garmin 496. Nothing else other than good paint and upholstery - maybe wingtip strobes.
"If the optional shortened flap handle is installed....." What is the story if the shortened flap handle is not installed???? Are there no limits at all?

The STC applicant/now holder initiated, and FAA apparently agreed, there was no performance or W&B change. I assume that was determined after the following procedures were conducted.

This is for Part 23 airplanes.
 
I accelerate, pull partial flaps and get off the ground, depending on wind, temp, load terrain I leave some flaps in to get over an obstacle. I have 4 positions of flaps. I can't give you any numbers, it just comes from lots of take offs and landings.
 
"If the optional shortened flap handle is installed....." What is the story if the shortened flap handle is not installed???? Are there no limits at all?


This is for Part 23 airplanes.


Yes, the AC is based on Part 23, but there are essentially the same requirements for CAR 3. Remember that back in 1965 when they switched from the CARs to the Federal Aviation Regulations pretty much all they did was renumber what already existed in CAR 3 to come up with 14 CFR 23. There is also CAM 3 which is like the current AC system, it tells you one way you can comply with the regulation. For compliance with CAR 3 there is no real requirement to provide any performance data, just that at the time of certification the test aircraft has to meet or exceed the minimum climb requirements set in CAR 3.85. Remember, under CAR3.777 there was no requirement for a manufacturer to supply a flight manual for aircraft under 6000 lbs. Piper elected to go the flight manual route so that is what we are stuck with. CAR3.777(g)(2) says they should provide "normal rate of climb, balked landing climb at various altitudes and temperatures." When modifying an aircraft, all you need to show is that it meets at least what is published, no need to go beyond that. The aircraft can perform better but can't perform worse, if worse you would need to publish new performance data. As for actual performance data on a modified aircraft, if you are getting down to that level of granularity in your flying, do the testing yourself to see how your aircraft performs.
 
Yes, the AC is based on Part 23, but there are essentially the same requirements for CAR 3. Remember that back in 1965 when they switched from the CARs to the Federal Aviation Regulations pretty much all they did was renumber what already existed in CAR 3 to come up with 14 CFR 23. There is also CAM 3 which is like the current AC system, it tells you one way you can comply with the regulation. For compliance with CAR 3 there is no real requirement to provide any performance data, just that at the time of certification the test aircraft has to meet or exceed the minimum climb requirements set in CAR 3.85. Remember, under CAR3.777 there was no requirement for a manufacturer to supply a flight manual for aircraft under 6000 lbs. Piper elected to go the flight manual route so that is what we are stuck with. CAR3.777(g)(2) says they should provide "normal rate of climb, balked landing climb at various altitudes and temperatures." When modifying an aircraft, all you need to show is that it meets at least what is published, no need to go beyond that. The aircraft can perform better but can't perform worse, if worse you would need to publish new performance data. As for actual performance data on a modified aircraft, if you are getting down to that level of granularity in your flying, do the testing yourself to see how your aircraft performs.
I agree with all you've said. My only reason was for pointing out that AC-23-8C specifically calls out Part 23 airplanes. While there are a lot of similarities, they are different certification parts and should not be confused.
 
I agree with all you've said. My only reason was for pointing out that AC-23-8C specifically calls out Part 23 airplanes. While there are a lot of similarities, they are different certification parts and should not be confused.

Yes, always best to stick to the Certification Basis specified in the TCDS when trying to figure stuff out.
 
Go up to post #7. Flaps are drag. Going up is a function of excess thrust, and in most aircraft excess thrust is max with flaps up.

If you climb at any speed where the aircraft will not stall clean (for a Super Cub that is just under 50) your best climb angle will be flaps up.

The reason the Super Cub climbs at a better angle with full flaps is that it is really, really going slow in a horizontal direction. You are at zero indicated airspeed with the nose uncomfortably high.
This is an unusual case.

Ditto the 180 at flaps 15. Sure, if you climb out at 60 with the flaps extended it is comfortable, but the flaps are then hurting your angle. Haul back on that yoke and really climb that thing - once - and if you assume the engine won't quit, you will be impressed (and probably convinced that you would never do that again).

Back to the Cub - grab an otherwise unmodified 160 Cub with a borer prop, go to full power and full flaps, raise the nose, and observe the angle. With two on board you should see a steady 45 degrees. If the engine quits, no amount of forward elevator will get you flying again for several hundred feet. And usually several hundred feet is well above your obstacle clearance altitude. In short, use this technique only when a life depends on it.
 
full power and full flaps, raise the nose, and observe the angle. With two on board you should see a steady 45 degrees. If the engine quits, no amount of forward elevator will get you flying again for several hundred feet.
I experimented with this, together with simulated complete power loss in my -12 a few times. It took me about 200 ft to recover. Spooky.
 
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I would submit that even though the reasoning seems rational to us pilots, it is still not true that any plane has a steeper climb angle with more flaps assuming it departs the same point on the runway as a plane without flaps. This assumes flying the correct Vx for that configuration as well. I have found this to be true in all of the planes I’ve flown including cubs. Maybe another way of thinking about it is that the angle of the climb increases at a faster rate than the forward velocity as drag is reduced. It gets intuitive fast in underpowered aircraft like a C-150. Its angle is essentially zero with full flaps at gross weight, that angle increases as flaps are retracted.

Now here is where I scratch my head a little… I’ve heard it said that slats increase angle of climb, but they also increase drag… I flew my current cub 25 hours before slats and have flown it almost exactly that much after adding slats. My pitch attitude on a max climb is certainly higher but I am not sure that my actual angle of climb is better. I havent measured but subjectively looking at my departure end trees I think it was better without slats. Hard to tell though. If it is in fact better then I would have to guess that the formulas given to calculate climb angle assume the basic airfoil remains the same. Adding slats does essentially change the airfoil. Anyone have any measured performance numbers for angle (not pitch attitude) of climb with and without slats?


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Back in the 1950's during 5th Grade we were exposed to Trigonometry. It's since worn off but there must be some way to measure increase in altitude (the opposite side) over a given distance (the adjacent side) and derive the angle of the hypotenuse.

Gary
 
Well, there must have been some reason that Piper recommends full flaps and 45 mph for Vx.

im guessing that may have involved a test pilot, but who knows, maybe they just penciled it out.

that configuration goes up with minimum forward motion. If you don’t trust your engine, perhaps there are other things you shouldn’t be doing as well. That said Vx in one of these planes in my opinion is a maneuver you use to get out of somewhere you probably shouldn’t have been in the first place.

MTV
 
It is pretty simple the slower you are going forward the more time you have to climb. The addition of full flaps allows for a 4 mph slower stall speed that is a big safety factor!! We are not talking about having a lot of excess energy in the way of speed to get over the trees. 45 mph is all you get from when you let go of the brakes. Using full or partial flaps to climb out or do steeper climbs in uncontrolled airspace gives you better over the nose visibility and depending on the cub can help with cylinder cooling. As far as PSTOL flaps, they will change things but I think the OP has some extra grunt up front to help with the drag.

DENNY
 
Except for a very few CFI's the last thing I'd ever do is climb near a stall. All the while depending on indicated airspeed to save me from myself and others.

Gary
 
I agree with supercub83a above most of the time. Flaps simply do not make an airplane go up.
The gotcha here is the Supercub will actually fly with full flaps at airspeeds that would bring it out of the sky flaps up. So you are not going up real fast at all, but you are also not covering much ground horizontally.

Gary has the right idea - don't do these departures. They work, but they are dangerous. Un-port a fuel bung, and poof - you die.
 
Some of us that live where Helio Couriers fly know well of their potential challenges. After departure while surrounded by tall vegetation or rising terrain ahead, then for some reason like inadequate relative wind or airspeed (at least ~50 knots IAS) not climbing well enough to clear obstacles. That can and does result in settling with full power, slats out, and flaps 20 CFIT to Earth. They are configured with LE slats and large flaps so that drag management is a primary concern. This I've been told by those that have flown them many times.

Now in a Cub or whatever with similar devices, adding induced drag beyond factory tests creates a similar challenge. They can fly slow enough, maybe not stall as soon or climb as quickly, and then suddenly loose whatever rudder or elevator authority the stock plane experienced. I'd be careful until I was convinced Piper's 45 IAS/full flap was still the best for Vx.

Gary
 
Gary,
you bring up a good point. I have alot of hours in Helio's and will say...the only time I experienced settling with power, was an extremely high DA day...as in 11,600 DA, while departing Pinedale WY. You learn quickly to crank your flaps up, rotate for takeoff and then push the nose over to close the slats and go for speed.

I have Carbon Concepts slats on my fat cub and I had pretty big slotted flaps, which I have now done away with the slots...they don't do what you think they do...I found them to promote a serious burble off the elevators, which went away completely, once the slot was closed back up.

The flaps provide a slight increase in lift and a serious amount of drag...for short field work, where the Helio shines, is the ability to quit flying at a specific spot. It does that like nothing else out there.

My fattie does it pretty well, due to the big 88" Mac prop. When it goes flat...you're about done. More like a Helio...drive it up with power at a specific attitude and when you pull the power off, you're done!!

The game changer in all this is power. If you have enough, you can exploit regimes, not normally available to lower powered craft. It if ever hiccups...you most likely have repairs to contend with.

Steve.
 
My Pstol flaps say use the same figures that are in the super cub book for a normally flapped super cub according to AA. I haven't flown a lot of planes but the ones I have flown, other than the SC, say best angle is with partial flaps. SC says full flaps which is good from a landing standpoint and the whole basis of my question. Coming into land with full flaps on a one way short strip and an elk runs out in front of you. Either maybe hit the elk or try a "go around". So now the cub is already set up for VX. My question is "do I get maximum benefit at 45 mph indicted or do I literally hang it on the prop to clear those trees that forbid a go around and am below 45 mph indicated and if your tube isn't the same angle as mine, to the wing, they aren't going to read the same anyway? I was hoping the answer would be simple like, yes 45 or no just hang it on the prop. As I remember VX goes up with DA and VY comes dn? Then there is the weight of the aircraft. I think it's just simpler and safer to just hit the elk.
 
A standard rule of thumb for flaps for shortest takeoff run, is to set them equal to the aileron that is at full travel in the downward direction. This worked well on the Helio, it works well in most others Ive flown.

There is no simple answer to your question, as weight is going to change the specific indicated airspeed...the number that's in the book, is a fairly consistent number to go off.

The answer in truth, is that there is a different answer for almost every loading scenario. Both Cg loading and weight loading or total wing loading.

In other words, you're asking for a number and it simply isn't there. What you will find in time, is that speed is more valuable in most cases than 5 feet. Once you start degrading yourself into this chasm of absolute max performance, to get away with things...it's just a matter of time, till you bust your ass...or your plane.

So...maybe think about realities instead. Time your distances for landing sites, by over-flying at 60 mph IAS and count out loud the seconds of your available landing zone....each second is about 100 feet. So if you overfly and count 8 seconds for an 800 foot overall landing zone and use half in real life...then when you takeoff, use the first half, to avoid having to contend with trees or obstructions etc...

In all my years of off airport flying, I've never yet had an animal run or stand in front of me on takeoff...or landing. I had an elk stand there for a few seconds in front of me, then leaped out of the way at just the moment I thought we might collide, but that's a whole nuther story.

I think in terms of a hierarchy of damage on off airport operations. Is the elk softer than the tree...? Is the tree softer than a big rock?? Is the big rock better than running into an airplane??? (I tend to look for soft things, when crap is rolling down hill fast).

Relying on a specific airspeed to attempt climbing over obstructions, will get you killed. Just a matter of circumstance. It's a matter of a cascading array of failures that put you into emergency management and probably overload. Life is about managing variables.

Speed is control, control is life and you only have to miss an object by an inch for it to not matter. But every time you do that....just know that you screwed up, well and good, if you have any hopes of becoming a wise old aviator.


I hope that helps answer why I'm not giving you a simple answer. ( cuz there's not one)


Steve.
 
As I noted above…..simple solution: Don’t put yourself in a situation where you NEED Vx

BTW, the Husky calls for full flaps for takeoff, and Vx climb. Of course full flaps is ~ 30 degrees, but those are huge flaps.

MTV
 
Thinking here about angle of climb testing in degrees vs aircraft configuration like slats. Fly level at desired climb speed and airplane configuration. Mark first waypoint on GPS (help may be needed), then immediately climb however many feet desired - like 500' or more, whatever to keep power constant. Mark second waypoint upon reaching desired altitude. Divide vertical feet by horizontal GPS distance made. Find Tangent* of that value to get degree. Repeat to reduce sampling error....math majors like at least 30 data points, but they're not involved or buying the fuel. Repeat with other configurations in low wind. Let me know if I FU and I'll fix it.

Gary
 
So if you are going to be going into one way only strips or very short strips several things should be considered. First as MTV mentions should you even try to land. Then plan for the crash even on a go around strip. What side of the strip will you do the least damage if you go that way Left/Right/Straight ahead? What is your ground loop point. Getting a tail or wing tip is a lot cheaper then flipping or flying into trees. If you somehow get yourself in a place that you don't have a good way out other than flying into trees at the end then man up set it on the ground and figure out what one of the crash sites you picked out you will use. I would avoid hitting the elk it could easily cause more damage than a ground loop or brush run. You are not flying a stock cub get up to altitude and practice full flap, full power, climbs at all trim settings than you will know what you can and cannot do with the plane. The stock cub numbers will get you to the parking lot of the ball park, you need to figure out what they are when you are in the batters box.
DENNY
 
The FAA made us do take off and climb tests like the handbook say, accelerate to 45 mph and full flaps when certifying the Sensenich ground adjustable prop. I argued and argued to no avail. I did it for the testing but would not do it in real life.
 
..... Time your distances for landing sites, by over-flying at 60 mph IAS and count out loud the seconds of your available landing zone....each second is about 100 feet. ....

Actually, you cover 100 feet per second at 60 knots (not mph).
That's about 69 mph.
And that's ground speed, not airspeed (indicated or otherwise).
 
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