Effectivness of Windsong Crow function when landing?

[jswain]

Hello,
i just got the first of my two Windsongs back in the air last weekend and after 15+ years it was as close to a religious experience as i have had in a while.

I have the mechanical crow function built in and set up (as are all the functions - built per directions) but it isn't active.

I now have no recollection of using the 'crow' function in the model and its
effectiveness.

So my questions to the group follows:
1) When using the flaps during decent or landing approach, flaps @ 70 degrees, what additional increase in descent can i expect from activating the 'crow' aileron function?

2)Do i need to be concerned with tip-stall when using at low landing speeds ?

I3) If so (tip stall) should i just point the nose down to increase landing speed ?

Right now, even with full flaps the model just keeps wanting to keep on gliding.

I am so glad i spent the time readying the model, it was really worthwhile -
now i just have to control the landing more to stop it from flying - the model really wants to just go and go.

thanks in advance for ideas/suggestions.
john s.

[John Cole]

John, you will get some good input on this one. Here's mine; I flew my Windsong for about 4 years, and never felt the need for crow. With 80+ deg flap, and down elevator compensation, you can drop the model in on A SPOT. If I remember correctly, I mixed in enough down elev (mechanically) so I could pop the flaps up at any time, and not stall. The way I always figured it is if the full sized ships didn't use crow, why would the model?? This was the 80's, remember... ;)


John

ps Got your email, good work on the 'new' maiden flights.

[jtlsf5]

Hello,
i just got the first of my two Windsongs back in the air last weekend and after 15+ years it was as close to a religious experience as i have had in a while.

I have the mechanical crow function built in and set up (as are all the functions - built per directions) but it isn't active.

I now have no recollection of using the 'crow' function in the model and its
effectiveness.

So my questions to the group follows:
1) When using the flaps during decent or landing approach, flaps @ 70 degrees, what additional increase in descent can i expect from activating the 'crow' aileron function?

2)Do i need to be concerned with tip-stall when using at low landing speeds ?

I3) If so (tip stall) should i just point the nose down to increase landing speed ?

Right now, even with full flaps the model just keeps wanting to keep on gliding.

I am so glad i spent the time readying the model, it was really worthwhile -
now i just have to control the landing more to stop it from flying - the model really wants to just go and go.

thanks in advance for ideas/suggestions.
john s.

Lots of up aileron (Crow) will add drag, slowing the model. It might slow a steep descent, but only because of the added drag. The downside is a loss of roll control. The mechanical linkage won't allow you to do what a computer radio will, ie reverse differential. When the ailerons are up, say 45 degrees, inducing roll when you have mechanical, normal differential doesn't help very much. You need to be able to hold the upgoing aileron steady and move the downgoing aileron down, and this won't jive with mechanical.

Yes, you will need to be aware of tip stall due to loss of aileron function with lots of crow. The safer way to use the crow capability is to have about 1/8-3/32" up aileron ONLY. This is effectively aerodynamic washout which will have a stabilizing effect and prevent tip stall. It also buys you some roll control, which you want on landing. The Song is a very short coupled plane, so it takes a bit of effort to induce yaw (change direction) at slow speed. The rudder may not be enough and some ailerons will help.

Overall, my preferred method for spot landing a Song is to come in at about a 30 degree descent angle with full flaps. Adjust glide path as needed, then flare at the last second and settle. The full flaps will hold the speed down and make this controllable.

Best option, though probably more than you want to do, is to convert to a 6 servo setup and a computer radio. It can be done with a little effort.

JT

[chipgibbs]

I am a long time Lovesong / Windsong builder and flyer and the Lovesong most certainly Does have differential ailerons even when CROW is deployed. The mechanical system in these planes is set up useing offset bellcranks both in the fuselage & in the wing. Bob Dodgson used to have a modification for a 4 channel radio to momentarily pop the ailerons up. This allowed pinpoint landing and speed control. You can deploy full crow and the plane comes straight down while still being controlable . The Aileron up position nearily stops forward motion while flaps alone
slow the plane and increase decent.

ChipG