Something else going on??

[Papa]

I was reading an article this morning that struck a chord with me. You know how many tip stall crashes we've seen at the downwind leg turn to crosswind at Rogo? What the author indicated was that the stall can be induced by up elevator movement. He described it like this.

On the downwind with a strong wind it's easy to have good ground speed but marginal airspeed. We don't know how much g-force we induce with the elevator. 1g doubles the weight of the model and also doubles the wing loading. We are already marginal and it's easy to exceed the limits of the wing to support the weight of the model. Because we are so low and slow we cannot recover and have this cartwheeling crash.

The answer seems to be to keep up your speed so you remain flying at all times and only seriously slow down on final.

Any comments?

Jack.

[piker]

I think that's very true, and it's compounded by the fact that we have to turn tight because of the road.  It doesn't happen at the south end of the field where we have lots of room for a large, and therefore, faster, turn to final.

[Ededge2002]

The downwind turn stall is a huge combination of things most of witch we are at a disadvantage. We have no instrument airspeed indication,  as you fly further to the left or right of your position the aircraft seems to be dropping because of our perception causing some to feed in more elevator and the ground speed can give us less time to nail the turn point again because of perception.   Another thought is that when the plane approaches 90°to the wind some of the lift is "blown off" the tip encouraging the tip stall.

These are things I've collected over the years and some may disagree. Just my thoughts and I agree that adding elevator near stall increases the wing loading.

[piker]

The solution is simple.  We just need to move Stouffville road a bit further north.... say 500 ft.

Can we do that during our spring clean-up?

[Papa]

It's all your fault anyway Rob.

You should have cleared the field 500' further south!

Jack.

[Michael]

I have had a few such crashes/mishaps preparing to land from the south.

The fault is in our flying; not in with the field.

Slow, curved and banked (ailerons) approaches, with up elevator and reduced power, are a recipe for crashing.

Keeping the plane as level as possible in the turn, keeping speed up, keeping the nose down, flying low, and flaring just before landing, is the best 'approach'.

[Andy Hoffer]

The downwind problem is exacerbated with a a quartering tailwind from outside of the traffic pattern, i.e from the southeast in a left-hand (counterclockwise) circuit or from the northeast in a right-hand (clockwise) circuit.  For example, on the downwind with a SE wind, as you start your turn onto the left base, the wing experiences a 40% increase in the tailwind component until the plane catches up with the tailwind.  Not a good place to be when low and slow.

Andy

[piker]

Sure!  Sounds easy enough, Michael 

Hey Jack.  I suggested that when we first saw the site, but Michael didn't want to 

[Michael]

Further south meant a lower level, which meant wetter.

It was a reasonable compromise at the time.

[Papa]

OH! so now you're both to blame. Anyone else you want to throw under a bus?  LOL.

Jack.

[sihinch]

I expect my name will pop up somehow.

[piker]

Further south meant a lower level, which meant wetter.

Yes.  I know.  We would have had our own float flying site.  You're making things worse for yourself   

That's O.K.  We know it was really Simon's fault.

[Michael]

I agree.

It's Simon's fault.

[thehaze]

With all that's been said. I think the safest approach to avoid a tip stall is to fly against the pattern on your final circuit and perform a split s over the north edge of the field. This will set you up perfectly for a nice landing. No turns involved.

[Ededge2002]

I've seen numerous 3/4 split S's performed.