spoilers v reflex ailerons

[simon_t]

You will get a little braking effect, but nothing like as much as with simple, small, airbrakes. The problem is you won’t get much drag. As the ailerons go up the model speeds up so you have to lift the nose a little, and the model will come in fairly nose high. The upgoing ailerons do help avoid tip stall. I have ha a couple of models configured like this, and although it is better than no braking devices, it really isn’t a very effective solution. With a K-3 you would get more braking effect with a modest side-slip.

Simon

[BrettW]

I tried some experimentation a couple of years ago with my 3m (Seagull) K8, equiped with small barn-door top-surface airbrakes to see how the two different approaches compared. The conclusions I came to support the posts on here that even small airbrakes beat reflex in slowing the model up for landing, but that reflex is certainly better than nothing. I agree that probably the most noticeable benefit from reflex is avoidance of tip stalling, something I've found beneficial with a couple of my power models that don't have flaps.

Cheers, Brett

[chris williams]

Why compare, when you can have both...? Coupled together you can achieve excellent glide path control.

[FrankS]

1) Spoilers/Airbrakes
2) Crow braking (if you have flaps)
3) Reflex

As Chris says you can also dial in a bit of aileron reflex with the airbrakes too.

Well worth taking the effort to build them in.

[chris williams]

Sometimes none, sometimes slight compensation needed...

[BrettW]

Yes, I should have added that if you've got both, then use both!
My initial comparison was primarily to look at the effects arising from each of the techniques, not to choose one over the other if you could use both.

Carried over from my competition days I still use a dose of 'servo slow' on flaps/brakes/spoilers/crow alongside elevator compensation on my scale models to guard against overly enthusiastic use of the handbrake when panic sets in! I guess maybe many others do the same?

Cheers, Brett

[ChrisJesshope]

In response to the query on pitch change, I use reflex as very effective brakes on a couple of models I have but I have to say these both have large 3/4 length ailerons. Also you need a significant reflex to get decent braking. I have used about 30 degrees of reflex, pretty much full travel so roll control is a little compromised as its limited to down travel on one side only, however with some rudder mixed in for landing I have had no problems. This does however cause a significant pitch down so need a fair bit of up elevator mixed in to make it manageable.

I'm pretty sure your K3 ailerons will not give you much braking, they are just too small.

[FrankS]

If you have aileron differential dialled in, see if you have the option to remove this as reflex is introduced, helps maintain roll control.

But if you have airbrakes you can ignore this

[ChrisJesshope]

No airbrakes Frank and they are pigs to land without the ailerons up. I do have differential dialled but I compensate by using dual rate trims which have settings for each flight mode. I don't think I can turn diff off selectively by flight mode.

[Peter Balcombe]

No airbrakes Frank and they are pigs to land without the ailerons up. I do have differential dialled but I compensate by using dual rate trims which have settings for each flight mode. I don't think I can turn diff off selectively by flight mode.

Can you add a mix with opposite differential mix to the ‘land’ mode?