CFOT,

Since we were getting off the short landing roll topic, I though I might start a new thread. I have always wanted to ride one of the N-S ranges out west with southwest winds while an identical single engine, low powered airplane flew the same route up high and compare performance. The ridge rider would get free natural ridge lift and the high guy would get stronger tailwinds and better true airspeed.

CFOT wrote, "No problem, I answer to worse than that most of the time. I don't have a VSI in the Champ, but I am thinking I would like to try out a variometer like the hang glider guys use. Would be fun to go over to the coast range with one on a windy summer day and fine tune my use of terrain strategies."

Have you noticed better performance down low? It sure takes a long time to climb up, without good thermals, with little engines and high density altitude.

Contact

contactflying wrote:CFOT,


Have you noticed better performance down low? It sure takes a long time to climb up, without good thermals, with little engines and high density altitude.

Contact

Honestly I never fly the Champ anything but low, so I don't really have a comparison . If I actually need to go somewhere I jump in the 182 or the 185.

I really enjoy flying through the hills and canyons utilizing the terrain for lift though. Would be fun to do a comparison like you said.

I was always going from Tohatchi to Santa Fe and back for Guard or later flying pipeline. The only recreational flying I did, for the most part, was with students. I traded an Ercoupe for a 7FC Champ. The 90 hp made it fly almost like a 90 hp Supercub and the light nose wheel was not much problem off airport because the weight on the main gear was so close to a 7AC that I could three point it on the mains and tail skid and hold the nose wheel off with full back stick until almost stopped. That engine was a -8; no starter or lights. But your eyes adjust to dusk and then darkness pretty well, if the prevailing west wind holds you up too much. Just had to stay low across the desert and give way to any at Gallup. They had a Flight Service Station at Gallup then. Stealth all the way.

The "ridge soaring" technique works well, even on small ridges. The (obvious) parameters are the efficiency of the airplane and the wind speed. So this technique is used more with gliders than powered airplanes, but the principle holds for both.

A couple of acquaintances of mine (from 30 years ago) set several speed and distance records flying along the Appalachians. The distance record was something like 1600 Kilometers, flying at 120 knots at ridge-top height. The ridge tops were less than a thousand feet above the valley floors, often far less. Now these were very high efficiency racing sailplanes, opposite end of the spectrum from back country airplanes. Those Appalachian records were almost pure orographic lift, with occasional lee wave lift. "Thermals" were not a significant part of those flights.

In the western deserts, we had combinations of all three of these types of free energy. Running along the White and Inyo mountain ranges on the eastern Owens Valley, you would see lift (and sink) from all three of these energy types, any of which would exceed the still-air climb rate of most powered aircraft (evidenced by the Fossett crash in that area).

Of more direct relevance to Contactflying's interest in exploring this stuff in light powered aircraft, the key will be developing safe flying practices in those conditions. There are significant gains in climb rate and achieved speed that can come from circling in the thermals that bubble up through mountain canyons and gulleys. But realize that you're looking at circling in or near those canyons, in turbulent air, at slow speed, at high density altitudes, a few wingspans from terra firma.

The intricate ways in which these lifting and sinking air bubbles interact with the surface, the terrain, and the winds defies any and all efforts to measure or predict. So rather than rules of thumb and formulaic procedures, Contact and any others playing around in these areas with light powerplanes will simply have to develop a sense, instinct, and gut feel like all of us glider guys had to do. There's a lot more to it of course, having an "out" at all times, little tricks to increase the roll rate of an airplane in an emergency, playing back and forth between kinetic and potential energy, etc.

Anyone seriously interested in this kind of flying, even in a bushplane, should consider some instruction and practice at Minden gliderport or an equivalent mountain-focused glider operation (Driggs, ID used to have one if I remember).

EZ Flap,

While I have never gotten any glider training, I have always appreciated talking to glider pilots. They seem to have a good feel for what the airplane wants to do. I think you are correct that low power airplane pilots could gain from glider instruction.

Always needing to get somewhere I have never tried circling in a bubble, even with a 65 hp Cub, Champ, or Taylorcraft. On course thermalling up works well in the afternoon heat, but if going west into prevailing wind in the southern Rockies I would encounter stronger headwinds than down low. Because of some crookedness in most ranges, I was almost always able to find an angle to ridge near desired course to get west using ridge lift. This way I could get over the divide staying fairly close to terrain all the way up. Once over, I would power descend to stay out of stronger winds up high. I even used ground effect in the desert and on mesas.

I am too old to go there, but it would be interesting to see collaboration between glider instructors and instructors in 65-160 hp airplanes on the use of natural energy. I think the mountain utility and safety of the normal two or four place trainer could be greatly enhanced through this collaboration. I know, the money is in big engine airplanes and very slick gliders. It is probably not doable. For a number of years, I did have a group of students who became Private, Commercial, and Military pilots who were able to greatly enhance the utility and safety of affordable normal training and starter airplanes.

Contact