I'm familiar with the relationship between wing loading and stall speed. I would think that a plane with lower wing loading would have better glide characteristics. Is that not so? Can you elaborate?
Foam glider vs. balsa vs. DLG
- Thread starter joshuabardwell
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I'm familiar with the relationship between wing loading and stall speed. I would think that a plane with lower wing loading would have better glide characteristics. Is that not so? Can you elaborate?
I'm familiar with the relationship between wing loading and stall speed. I would think that a plane with lower wing loading would have better glide characteristics. Is that not so? Can you elaborate?
quorneng
Master member
It depends what characteristics you mean.
In terms of the best glide angle its all about the planes aerodynamics not weight. Identical planes will achieve the same glide angle regardless of their weight but the heavier plane will go faster.
For thermals you need a plane that flies slowly (low wing loading) to keep in the rapidly rising thermal 'core' but to get between the thermals you need both speed and glide angle (high wing loading). These are conflicting requirements so glider wings tend to have specialised wing sections to get the best possible performance in both cases and may use flaps to achieve it.
For efficiency gliders have very high aspect ratio wings but this gives a low roll rate, limits the turning radius and poses structural limitations. Most are both speed and 'g' limited.
The big wing span of a glider also tends to mean that if you stall in a turn the inside wing will drop, usually severely, requiring significant height to recover.
Flying a glider is very different to a conventional power plane.
In terms of the best glide angle its all about the planes aerodynamics not weight. Identical planes will achieve the same glide angle regardless of their weight but the heavier plane will go faster.
For thermals you need a plane that flies slowly (low wing loading) to keep in the rapidly rising thermal 'core' but to get between the thermals you need both speed and glide angle (high wing loading). These are conflicting requirements so glider wings tend to have specialised wing sections to get the best possible performance in both cases and may use flaps to achieve it.
For efficiency gliders have very high aspect ratio wings but this gives a low roll rate, limits the turning radius and poses structural limitations. Most are both speed and 'g' limited.
The big wing span of a glider also tends to mean that if you stall in a turn the inside wing will drop, usually severely, requiring significant height to recover.
Flying a glider is very different to a conventional power plane.
A hotliner was not originally designed as an aerobatic airframe. It is a detuned "sport" version of an F5B airframe. That particular competition class is designed around limited motor run (hence very powerful motors). One half of the competition is to do the most number of power off laps around a course, hence powerful motors for quick acceleration for a few seconds, then very high speed low drag airframes to do as many laps as possible. The second half of the competition is thermalling. Here again is a limited motor run to gain altitude, then the thermalling occurs way high up in the air where thermals are real big. You don't need to be able to slow way down and work small tight thermals.
To watch real F5B planes doing high speed laps is a jaw dropping experience.
Flying any glider way downwind is always bad, whether the glider is powered or not. Work from thermal to thermal and try to make your way upwind. I only point this out because this is not really a deciding factor in choosing a first glider.
Good news! I may have hooked up with somebody who knows slope soaring locations in Knoxville, so that's nice. I decommissioned my first PopWing when I built my second one, and I am going to convert it for soaring by taking off the motor and putting a smaller battery on it to get the CG right. Should cost about $25 all in, and then I can get some kind of gliding experience under my belt.
FAI-F1D
Free Flight Indoorist
For a beginner, that thermalling performance is the priority. This shows in the success of the Radian and other foamies which have little to no thermal-to-thermal abilities, but low enough wingloadings to ride very light lift. Those also happen to be the easiest planes out there to fly. I think the Radian is one of the best trainer platforms out there, and it's not a half bad thermal duration trainer either.
Joshua's original question makes clear that he has no thermalling experience, but a good level of flying experience, which is why I suggested a balsa model--it won't break the bank, still has the low wingloading, but gets him some of the speed range of a high performance model.
I've flown some of the much higher performance models, and between the expense and the more demanding flight characteristics, I would advise any newby to soaring to stay away from those until they've got their feet under them. That's why I also recommend against DLG's as first soaring platforms.
Uhm...have you flown a glider with good wind penetration? The folks who have it use it. They go waaay downwind to get the most out of that thermal, and they know how to get back upwind, too. I've got a little experience doing that--it's a necessary skill, though a bit nerve wracking. What's really amazing is what you can do when you have the ability to reflex the flaps and ailerons and dip the nose a couple degrees to get up to 100 mph for that return to home (yes, that's in the league of Supra's and things like that, so a little academic here).
