This might be a topic for the technique forum but I think it may be different with floats so I will ask it here
The poh for my plane says get off the water and climb out at 73mph for best angle of climb? At 20 degrees flap?

I believe best angle is the shortest distance to altitude
A 20000 hour pilot that I fly with insists that accelerate in ground/lake effect to gather as much airspeed as possible then do a rapid climb at the last minute
I fly a 182 with stol kit and 260hp on edo 2870s
Any thoughts
I know you don't want to be close to stall as you get to trees but doesn't best climb speed afford lots of stall room?
What are the thoughts and experiences on the forum?

Airspeed is altitude and altitude is airspeed according to Wolfgang Langewiesche. One can be traded for the other at will.

The airplane will fly at a much slower airspeed and accelerate much faster level in low ground effect. High wing and floats diminish this free energy somewhat, but it is still free energy until we climb out of ground effect.

Best angle is what we want when best rate would cause us to clip the trees. Best angle, because it bleeds energy, is not what we want either well before the trees or well above the trees. Once we are up there, out of ground effect, we are bleeding energy and have given up free energy that we can never get back. If all goes well, other than being bad form, it doesn't matter. If all does not go well, we will have to level the airplane to be able to fly all the way to the crash.

Most of us who have flown thousands of hours have sorted this out. The extra energy of low ground effect has helped me clear many a tree and given me maneuvering speed on several engine failures.

Stay level in low ground effect as long as you can stand it and clear the trees with as little to spare as you can stand. Your airplane will appreciate it. You will have to hold onto what little airspeed you have and crash straight ahead less often.

Look, the manufacturer of your airplane has published a set of DOCUMENTED procedures, complete with speeds, that were flight tested during certification. That is not always the case in much older aircraft.

But, if I'm looking at a relatively short lake, with trees all around, I'm going to follow the manufacturer's recommendations to the letter.

That is until someone takes my airplane out and conducts flight test to DOCUMENT that "Stay level in low ground effect as long as you can stand it" actually will get you over the trees in a shorter forward distance than following the manufacturer's proven procedures.

So, here's the question for Contact and for you as the pilot of this little test: Precisely WHERE is "Stay level in low ground effect as long as you can stand it"? What if I decide to climb out of ground effect a wee bit early cause I get nervous, or conversely, I stay in ground effect a wee bit too long? Tell me how you QUANTIFY precisely where one should leave ground effect and perform a "zoom climb" to clear the trees.

Now, to be sure, I'm an advocate of staying in ground (water) effect as long as practical prior to climbing under NORMAL circumstances. But, when it comes to a true short field, I'll follow the manufacturer's recommendations, as long as those have been flight tested and thus proven to work.

And, yes, I've done precisely that on a couple of occasions, taking a portable GPS around to the other end of a small pond, figuring the distance to the trees, consulting the distance given in the POH, then flying precisely the procedure and speed given in the POH.

For what it's worth. You can make up your own procedures if you like, but they need to be repeatable reliably and proven with flight test to be better than the alternative. Me, I'll stick with data that's been proven and documented. I'm not a factory test pilot, but they spent a lot of time and effort figuring out how best for MOST pilots to get over the trees in the shortest distance.

MTV

mtv wrote:Look, the manufacturer of your airplane has published a set of DOCUMENTED procedures, complete with speeds, that were flight tested during certification. That is not always the case in much older aircraft.

But, if I'm looking at a relatively short lake, with trees all around, I'm going to follow the manufacturer's recommendations to the letter.

That is until someone takes my airplane out and conducts flight test to DOCUMENT that "Stay level in low ground effect as long as you can stand it" actually will get you over the trees in a shorter forward distance than following the manufacturer's proven procedures.

So, here's the question for Contact and for you as the pilot of this little test: Precisely WHERE is "Stay level in low ground effect as long as you can stand it"? What if I decide to climb out of ground effect a wee bit early cause I get nervous, or conversely, I stay in ground effect a wee bit too long? Tell me how you QUANTIFY precisely where one should leave ground effect and perform a "zoom climb" to clear the trees.

Now, to be sure, I'm an advocate of staying in ground (water) effect as long as practical prior to climbing under NORMAL circumstances. But, when it comes to a true short field, I'll follow the manufacturer's recommendations, as long as those have been flight tested and thus proven to work.

And, yes, I've done precisely that on a couple of occasions, taking a portable GPS around to the other end of a small pond, figuring the distance to the trees, consulting the distance given in the POH, then flying precisely the procedure and speed given in the POH.

For what it's worth. You can make up your own procedures if you like, but they need to be repeatable reliably and proven with flight test to be better than the alternative. Me, I'll stick with data that's been proven and documented. I'm not a factory test pilot, but they spent a lot of time and effort figuring out how best for MOST pilots to get over the trees in the shortest distance.

MTV

Just a question for all, but I would think that just about anything on floats when you break the water has very much ground affect that would help you accelerate very much faster than climbing out. 1 foot above the water is about 2/3's the length of the wing to the wing??
Just looking for information, have not been there enough to know!

MTV is absolutely right. If your lake or field is so short that you need to pitch up to best angle as soon as you have accelerated to Vx speed in low ground effect, you need to do that. I think your friend was advising not to do that sooner than necessary and hanging out up there out of ground effect well before the trees.

In many years of spray training, I never had a student hit a tree. It seems most have an aversion to that. Pull up too early and bleed energy ; fairly common.

Just a question for all, but I would think that just about anything on floats when you break the water has very much ground affect that would help you accelerate very much faster than climbing out. 1 foot above the water is about 2/3's the length of the wing to the wing??
Just looking for information, have not been there enough to know![/quote]

If you're suggesting that ground effect is less powerful in a seaplane the answer is yes, for the reason you noted. Look at a seaplane sitting on the ground and you'll realize how far above the keels the wing is. Especially so since most seaplanes are high wing.

But with a seaplane, it's even more essential to get the airplane into ground effect (and it will be low ground effect as Jim refers to) because the hydrodynamic drag of the floats in the water is so massive. This varies somewhat with the model of floats or hull, but water drag is always huge. So getting the plane into the air at the slowest possible speed, then letting the plane "catch its breath" accelerating in what ground effect you've got is essential in many seaplanes, particularly if they're loaded.

MTV

With better instrument technology, why hasn't any aircraft manufacturer published the airspeed their airplane will fly in low ground effect? Not that we need to be looking at the airspeed indicator, but to emphasize that need to pull off into low level ground effect first. It misleads students when Vso is the lowest V speed. How many students think they land at Vso? In low ground effect, with the stick full back, Vso would be too fast.

I have found the manufacturer's airspeeds to be a good starting point, however, most of the planes that I have flown have been modified, crashed (some of them multiple times) or both, so the indicated airspeeds can be nebulous at best. It got to the point that when I was instructing for the company, I would load the planes to gross, and cover the airspeed indicator so the pilots would look at the trees and see what attitude was giving them the best climb.

mtv wrote:Look, the manufacturer of your airplane has published a set of DOCUMENTED procedures, complete with speeds, that were flight tested during certification. That is not always the case in much older aircraft.

But, if I'm looking at a relatively short lake, with trees all around, I'm going to follow the manufacturer's recommendations to the letter.

That is until someone takes my airplane out and conducts flight test to DOCUMENT that "Stay level in low ground effect as long as you can stand it" actually will get you over the trees in a shorter forward distance than following the manufacturer's proven procedures.

So, here's the question for Contact and for you as the pilot of this little test: Precisely WHERE is "Stay level in low ground effect as long as you can stand it"? What if I decide to climb out of ground effect a wee bit early cause I get nervous, or conversely, I stay in ground effect a wee bit too long? Tell me how you QUANTIFY precisely where one should leave ground effect and perform a "zoom climb" to clear the trees.

Now, to be sure, I'm an advocate of staying in ground (water) effect as long as practical prior to climbing under NORMAL circumstances. But, when it comes to a true short field, I'll follow the manufacturer's recommendations, as long as those have been flight tested and thus proven to work.

And, yes, I've done precisely that on a couple of occasions, taking a portable GPS around to the other end of a small pond, figuring the distance to the trees, consulting the distance given in the POH, then flying precisely the procedure and speed given in the POH.

For what it's worth. You can make up your own procedures if you like, but they need to be repeatable reliably and proven with flight test to be better than the alternative. Me, I'll stick with data that's been proven and documented. I'm not a factory test pilot, but they spent a lot of time and effort figuring out how best for MOST pilots to get over the trees in the shortest distance.

MTV

You must have had a damned good portable GPS, like surveyor quality. A spot that short doesn't seem worth the risk for a government job, 'less it was in combat. [emoji6]

I know you're trying to give the OP good, safe advice. But I bet your ass has a way better feel of what's going on than the POS POH.

gbflyer wrote:

mtv wrote:Look, the manufacturer of your airplane has published a set of DOCUMENTED procedures, complete with speeds, that were flight tested during certification. That is not always the case in much older aircraft.

But, if I'm looking at a relatively short lake, with trees all around, I'm going to follow the manufacturer's recommendations to the letter.

That is until someone takes my airplane out and conducts flight test to DOCUMENT that "Stay level in low ground effect as long as you can stand it" actually will get you over the trees in a shorter forward distance than following the manufacturer's proven procedures.

So, here's the question for Contact and for you as the pilot of this little test: Precisely WHERE is "Stay level in low ground effect as long as you can stand it"? What if I decide to climb out of ground effect a wee bit early cause I get nervous, or conversely, I stay in ground effect a wee bit too long? Tell me how you QUANTIFY precisely where one should leave ground effect and perform a "zoom climb" to clear the trees.

Now, to be sure, I'm an advocate of staying in ground (water) effect as long as practical prior to climbing under NORMAL circumstances. But, when it comes to a true short field, I'll follow the manufacturer's recommendations, as long as those have been flight tested and thus proven to work.

And, yes, I've done precisely that on a couple of occasioIns, taking a portable GPS around to the other end of a small pond, figuring the distance to the trees, consulting the distance given in the POH, then flying precisely the procedure and speed given in the POH.

For what it's worth. You can make up your own procedures if you like, but they need to be repeatable reliably and proven with flight test to be better than the alternative. Me, I'll stick with data that's been proven and documented. I'm not a factory test pilot, but they spent a lot of time and effort figuring out how best for MOST pilots to get over the trees in the shortest distance.

MTV

You must have had a damned good portable GPS, like surveyor quality. A spot that short doesn't seem worth the risk for a government job, 'less it was in combat. [emoji6]

I know you're trying to give the OP good, safe advice. But I bet your ass has a way better feel of what's going on than the POS POH.

Heck, most any portable aviation GPS is WAAS enabled nowadays....mine was. With WAAS, you're pretty much guaranteed accuracy within 3 meters or so....close enough. The particular airplane I was flying that day was a Husky, and the POH in the Husky (and many NEWER aircraft) is actually pretty complete and filled with useful info. Also, I know the guy who did the seaplane flight test....and he was a pretty low time seaplane pilot, though one hell of a flight test guy, so I figured I could at least duplicate his testing. And, I had 30 foot trees not 50 foot, and I gave myself an extra hundred feet distance to clear em.

My original plan when I landed there was to step turn out of there (little round lake), but what I hadn't planned on was the lake (pond) was shallow, and the plane didn't want to step turn with the keels in the slop. So, Plan B....hard to step off the distance to the trees, unless you are VERY blessed. So, take the GPS to the trees opposite, save a waypoint, go back to the plane, slide it as far up on the bank as possible backwards. Consult the POH for max takeoff distance to clear on floats, which in this case was 1200 feet, as I recall. I had 1300 or so, and trees were 30 feet, etc. ANd, POH data was at gross. We were at least 90 pounds below gross.

Turned out to be a piece of cake. That certainly wasn't even close to the toughest water flying situation I ever got into.....

MTV

Tight is tight, but when up into low ground effect we need to direct our course to the bottom of any obstruction we can't rudder turn around. We have the top of the obstruction peripherally. When the top gains our undivided attention, we change our directed course to the top. Vx? No. Vy? No. The pitch angle that will put us just over? Yes. The hand follows the eye and we go over. If things go wrong,we have maneuvering speed that allows us to direct our course elsewhere. Elsewhere may be between two trees, but even this is best done under control. Falling into trees generally hurts more.

In a hypothetical world, the best way to climb over an obstacle would be to break water, accelerate to Vx, then maintain Vx till clear of obstacles. The problem is, there are too many variables in the real world. Remember, published Vx is at a certain weight and altitude. It is also based on a certain configuration, namely stock. Your 182 with an upgraded engine and floats (and possibly modifications to the wing??) will not be what is in your original POH. Then factor in any changes in relative wind (think even small amounts of gusty wind) and airspeed indicator inaccuracies and you have a problem with factory Vx.

Most experienced pilots facing a confined area will get the aircraft off the water, clean it up and accelerate under max power, then trade that excess airspeed for altitude as required to clear obstacles. Popping the flaps back to max climb (20 in most cessnas) is an extra tool to use in that scenario.

Published Vx may or may not have a decent buffer over stall speed depending upon conditions. However, given any small hiccup in your engine, you will not have any buffer. Try pulling power off in a Vx climb sometime and you will see what I mean. Be sure to have plenty of altitude and be ready to pitch down NOW.

North River wrote:In a hypothetical world, the best way to climb over an obstacle would be to break water, accelerate to Vx, then maintain Vx till clear of obstacles. The problem is, there are too many variables in the real world. Remember, published Vx is at a certain weight and altitude. It is also based on a certain configuration, namely stock. Your 182 with an upgraded engine and floats (and possibly modifications to the wing??) will not be what is in your original POH. Then factor in any changes in relative wind (think even small amounts of gusty wind) and airspeed indicator inaccuracies and you have a problem with factory Vx.

Most experienced pilots facing a confined area will get the aircraft off the water, clean it up and accelerate under max power, then trade that excess airspeed for altitude as required to clear obstacles. Popping the flaps back to max climb (20 in most cessnas) is an extra tool to use in that scenario.

Published Vx may or may not have a decent buffer over stall speed depending upon conditions. However, given any small hiccup in your engine, you will not have any buffer. Try pulling power off in a Vx climb sometime and you will see what I mean. Be sure to have plenty of altitude and be ready to pitch down NOW.

You are correct to a degree, but the way I operate a modified airplane is to use the published data in the POH (assuming there is one, and it's relatively complete with data) even on an airplane that's been modified with STOL mods.

That's how you stay alive in these things, frankly. In that case, the STOL mod SHOULD give you an even better margin.

But, as you say, there are different floats, different propellers, etc. In my experience, though, the only time I deviated from the factory recommendations is when the mods on the airplane actually deteriorated performance....as is the case with certain models of floats.

And, yes, obstacle clearance numbers are generally published for maximum legal takeoff weight.....as is stall speed and Vx. So, any time you're below max legal takeoff weight, your performance SHOULD be better, neh? If your airplane actually performs worse at a lower weight, there's something seriously weird going on.

So, in matter of fact, the factory numbers GENERALLY work pretty well on most modified aircraft as well, since most mods actually improve performance.

There are exceptions, however....as in increased gross weight, but those mods generally come with updated performance data, and MOST of them come with some sort of performance enhancements as well.....wing extensions, bigger engines, etc.

The other exceptions are those airplanes, such as virtually all the older airplanes, which had VERY minimal or even no data provided the pilot on performance. Then it's up to the pilot to derive this information. My PA-11 is one of those. There is no POH, so I'm on my own to figure out what works best, including figuring out what Vx might be.

But, whether most "experienced pilots" do as you say in a TRULY confined area is debatable. Again, your airplane may not have very good performance data provided, in which case you need to figure it out yourself.

And, yes, in most cases, EXCEPT truly confined areas, I'd get a seaplane into ground effect, let it accelerate, then climb over the trees, as Jim says, just barely over the trees......

But, you can't generalize by saying "accelerate in ground effect, clean it up, then climb" in a discussion like this. That may work in certain specific aircraft, but this is a general discussion, not specific to one aircraft. Many aircraft much prefer to climb with some flaps down. The aforementioned Husky likes to climb with FULL flaps, for example, at least initially.

Flaps are your best friend in a Beaver--be very circumspect about pulling the flaps out from under one of them in a climb. Every plane is different.

In general operations, I've done lots of things that weren't as specified in the POH as the best way to do something. But, if there is specific guidance in the POH on how best to achieve max height over an obstacle, I would generally follow that guidance. If the plane is modified with STOL mods, it should work even better.

I like margins when it comes to getting over obstacles.

MTV

I don't have anything meaningful to add but a couple experiences came to mind while reading this thread.

Back when I was a new pilot a equally green pilot friend and I decided to go hit some front country runways; Garden Valley, Warm Springs, Weatherby and Atlanta. Of course we left Nampa with full fuel and nothing but a sectional and my recollection of what lowflynG3 had said about the strips here on BCP.

We were having a ball bouncing in and out of those airstrips. I was nervous about Atlanta because of the story I heard about a cub crashing after a balked landing; this was my fist "one way" strip. The problem didn't come till it was time to take off. Rising terrain all round, I thought a remembered a narrow section in the river canyon just down stream so I was worried about just turning right and following the river. I decided to turn left, up canyon, do a 270* turn then fly down river. By doing so I'd have more altitude and would be able to see the canyon before committed to flying through it. I remarked to my buddy that climb speed was 70mph. We took off as planned, flew straight ahead till the terrain made us begin our 270* turn. By this time we were fully committed and we could see it was going to be close. I was focused on finding the shortest trees possible to fly over while making the turn and my friend instinctively started calling out our indicated airspeed. Him doing that likely saved our lives, it was that close.

The Luscombe Manual only lists a climb speed (70mph) and on this occasion it worked...barely.

Several years later I was touring the Idaho Backcountry with my dad. After stoping a few places we decided to check out Bernard Creek. We both remembered the story my grandpa told about making his friend walk from Bernard to Flying B because he didn't think he could get out of Bernard with his friend onboard. Bernard is a one way strip that you have to land downstream and takeoff upstream. He knew the takeoff was going to be close and his Luscombe was going to need the entire runway. He was right, as the ending the runway was nearing he was still firmly planted on the ground. He horsed the plane into the air mowed his way through the willows. After landing at Flying B he cleaned the willows out of the gear, loaded up his friend and headed home.

When it came time for us to leave Bernard we were a bit nervous. The soft dirt slowed is down a bit but I got us into the air as soon as the airplane was willing. We stayed in ground effect till we had plenty of airspeed and then proceeded to climb. Had we needed to "zoom" over some trees we could have but the willows weren't 10' tall.

I think in most situations either using the POH numbers or "zooming" over the obstacle will work. I prefer the "zoom" method. Maybe that's because I've never flown anything with a POH or maybe it's because it is more fun to zoom[emoji41]