N-Jacko wrote:As you say, that's a nice leaflet, but it doesn't extend to DA over six or eight thousand feet, doesn't allow for different weights, and ignores sloping sites.

On the other hand, the modified Air Force trick of measuring actual ground speed in a stall in the pattern or high pass allows for weight, wind and any DA. Armed with that speed and the physical dimensions (length and height) of the landing site it's straightforward mental arithmetic to predict whether a properly executed landing can be made without excessive braking.

I didn't mean to ruffle quite so many feathers, but I find the method is simple and accurate and I just wondered if anyone else might care to try it. No problem if not, but please let me know if you do.

P.S. if nothing else this thread has cleared up the weather here - clear skies and ground frost now

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When in doubt, don't.

Benjamin Franklin

gbflyer wrote:I cannot imagine stalling my airplane in a "pattern" above an unfamiliar landing area to determine if there's enough room. If the pilot did that to me as a passenger, I would be searching the cockpit for a fire extinguisher to knock his ass out with. No offense. [emoji1]

N-Jacko wrote:MTV's method obviously works, but I would liken it to making a ballistic table for long-range shooting by measuring actual bullet trajectory (windage and elevation) at various ranges.

That can be done, and it works after a fashion, but to an engineer it seems like the hard way when we can plug wind, range, atmospheric pressure, temperature, muzzle velocity and ballistic coefficient into a simple equation and kill or convert our V-bull sighters to finish our string before an unreadable squall catches out our competitors. Of course, we need experience (and more than a little luck) to estimate wind for long range shooting, particularly in the mountains.

An airplane is just another machine which obeys the laws of physics, so if we're happy to trust engineering calculations as we drive across a new bridge, we should be able to do the same for take-off and landing.

I'm not for a moment suggesting that experience is unimportant, but if we ignore the science and just treat off-airport flying as an art, we're just not using the tools developed over centuries by the human race.

I've found that the above formula correlates pretty well with actual landings, in spite of the seemingly broad assumptions involved (many of which tend to cancel each other). Doing the same for take-off shouldn't be beyond the wit of man. Our VSI gives an indication of net power available at that place and time, and all other data for the energy calculation can be measured on site or beforehand.

Really tight fields require our attention outside. .... Because of greater possibility of traffic, however, the home airport requires our full attention outside also.

I cannot imagine stalling my airplane in a "pattern" above an unfamiliar landing area to determine if there's enough room. If the pilot did that to me as a passenger, I would be searching the cockpit for a fire extinguisher to knock his ass out with. No offense.