Basic Aeronautics

[KENNYGLIDE]

Sorry Brian ..they've all passed out....exhaust fumes ....? Or maybe just slack in the pants......?

[Celwin]

... been a but busy ...

What's peoples views about flying at low speed into the wind then turning downwind? Lots of theory says that airspeed is airspeed. The aircraft doesn't know if it's flying in wind or not so that turn downwind is the same as turning when there's no wind.

[KENNYGLIDE]

Interesting question Marcel, maybe this one is easier to answer... My Dagger requires very little elevator movement.... It tends to pitch up very quickly from level flight.. just a touch and up she goes... Having said that, the small amount of elevator movement required still gives it a quite a sharp turning circle.CofG seems to be ok.????

[Celwin]

How does it fly inverted?
What's the stall like at low speed or with power off? (I guess that last question is a bit silly. Kennyglide never flies at low speed... even when his bixler is on the ground, it's still not at low speed..) ?

If it has a symmetrical wing and flies inverted almost hands off, the C of G is good, almost too far back. If it drops a wing at low speed in a tightish turn, your C of G might be too far back. Sensitive elevators are a sign of the C of G being too far back, but not always. A short wing to tail distance will always result in a sensitive elevator.

[Brian Clarey]

Hi guy`s..... personally,I think Marcel has got it in one!! From what I have observed lately at the field, insufficient emphasis is placed on the COG location. When you consider that we are talking about small percentages of the chord, approximations are rarely good enough. Test equipment should be used to get the best results . If it is considered that air is alway`s in a horizontal stream, which it is not, then the angle of attack of the wing, relative to the air stream can be best visualised. The greater the angle the more lift, till it reaches a point of maximum lift...then it starts to act as an air brake . Similarly, if the model is tail heavy then adverse control can be expected due to the tail down attitude, increasing the angle of attack.....Nose heavy, and the model will want to nose dive.....It could be a worthwhile investment for the club to purchase a test rig to prove one way or another if the set up is absolutely correct. It could improve members confidence and increase participation. These items are not expensive for the accuracy they provide.

[Celwin]

I had a fly of Vince's new Lazy Bee yesterday afternoon. What a cute thing it is! The model was pretty cute as well...

It was fairly sensitive in pitch, especially when down elevator was nudged. If you've never seen a Lazy Bee (this was my first, apart from seeing them in magazines), they are short and stubby with a very thick wing with long chord and is so far away from a gliders high-aspect ratio design, it is almost a no-aspect ratio. Seriously though, Vince put in an extra couple of ribs to give it a greater span, because he could. The tips of the wings are turned up, but I can't recall if it is just dihedral or was polyhedral. From memory, it was flat all the way across until the last 100mm or so. It really is only the tips, so won't provide much self-leveling.

When I was trimming it out, it would do a gentle and gradual nose dive, with a fairly abrupt pull-out (probably me). Once trimmed to fly straight and level with low power, if I let it dive it wouldn't pull out. I expected a gentle pull out as the airspeed picked up, which is typical of all flat-bottomed airfoils and most semi-symmetrical ones. It also needed very little attention to the elevator when flying fast or slow once trimmed for cruise. I didn't expect that as there wasn't an obvious down-thrust on the motor. I'm wondering if it may not have enough angle of attack on the wing.

By the way, it glides beautifully. Didn't expect that either, because it looks as aerodynamic as a pelican, which to my eye shouldn't be able to thermal.
My first landing attempt would have seen it touch down halfway to the front gate...

It looks awesome Vince and flies beautifully. What a great outcome for such a long scratch build. Thanks for letting me fly its maiden. It was an honour.

[Brian Clarey]

Vince, cute !! you`ve definately consumed far too much exhaust fumes. Better off flying electric for a while to let your system recuperate.

[KENNYGLIDE]

Yeah this  new  Dagger has a longer wing to tail distance than the first as the 55 motor is heavier than the 45 evo.so I allowed for that.I have the c of g set at exactly 1/3 of the chord.....

The fuel tank is halfway in front of the leading edge and is quite large and weighty when full....and then it feels nose heavy....i thought that would compensate if in if the  c of g was set too far back
 I did notice on landing it glided quite well and relatively slow.... almost flaring without input...could that indicate tail heavy.?..seems to me maybe try some more weight in the front....  PS: I'm  feeling a little jealous...No one calls me cute.lol

[Brian Clarey]

Ah, we all luv ya ken!!

[KENNYGLIDE]

Awww gee... Thanks Brian ,LOVE YOUS ALL.