need help to make scale ,slotted flaps and linkage.. how much does the, air slot ,really help?

At our size and reynolds numbers I'd suspect not a lot. The function of the slot is to direct high speed air over the leading edge of the flap surface and in effect produce a "blown" surface that is resistant to stall so it can more ably direct the upper surface air downwards. But at our sizes the air does not flow the same way through a scale gap as it does through the full sized versions. And most of us lack the wind tunnel needed to develop a working slotted flap that will be effective in our sizes.

But all is not lost. If you just copy to scale the original system the gap may or may not help but it most likely won't hurt. If it doesn't work as intended then your flap will act like a plain flap and that's not so bad either.

As for hinge design and any associated tracks or other hardware you'll need to ask about options in another forum that's related to such things.

THANKS .. I TRY A 3/16 SLOT

Report back with the results. This is the sort of thing that not many ever bother to play with.

It would be interesting if you were to tape on some 2 inch long length's of kitting wool on the flaps outside of the prop blast and have someone view them through binos while it's doing slow flybys. If the slot is helping you should see the upper surface tufts pointing down to the trailing edge to a marked degree. If the slot isn't able to fill in the stagnation bubble on the upper side of the flap then the tuft will be fluttering strongly in the vortex flow. Try different angles to see how well it works out. At some point it WILL stagnate and produce more drag but up to that time it should be a slower flying speed with little power. Once you drop the angle a bit more and it stalls the flap despite the slot you may find that it requires a nudge more power to maintain height and/or flying speed.

HI. i have been doing test as you sugested,.. i used shop fan first.very critical on the, radius and, gap set up.3/16 on a .65 radius is what ill use. the hinge pivot point is the real work. over 20 hours in it so far.. lots of ways to do it. i want it to come apart for painting. "thanks for interest." i wish the plane was larger so it would be easier to work out..will post pics for sure..

Check this mechanism out:

http://www.freepatentsonline.com/6010097.pdf

wow .. will save that for bigger project..thanks

tested new slot idea.3/16 slot to big . no air speed.1/8 slot worked super!! .625 leading edge radius on flap. flat on the bottom side.55 deg flap turns air flow 120 deg.!!totaly laminar...tried smoke but did not set up for a good test. will do it wednesday.used yarn for first test..

You're my hero of the week for doing this!

Some seriously nice results you've got there so far. I was a bit dubious that slotted flaps would work at all for our model size. But from the sounds of it you're clearly seeing it work with great success.

A flap that redirects the air such as this will greatly increase the achievable lift coefficient for a given size wing and be a big advantage in models where we want to achieve a very wide speed range to allow blistering fast speeds but still slow down to acceptable landing and takeoff speeds. And since size counts when it comes to high speed drag being able to make a smaller model with the same size jet turbine or EDF means the high speed can be higher. Yet with the lift you'd get from flaps that can maintain directed flow you can safely go smaller and still get the lift at regular landing speeds to allow the use of a smaller wing and model.

.....and the tail will need to be strong enough to keep the wing and the flap at the right angle, fighting the increased pitch moment.

Consider that the strong downwash created by the deployed flap will reduce the AOA of the stab; ie, the airstream will heat the stab and elevator from above.

THANKS FOR INPUT..I CAN CHANGE HOW MUCH THE SLOT IS OPEN WITH THE PIVOT POINT.MAYBE A LITTLE {SLOT} AT 20 DEG. FLAP,MORE {SLOT} AT 45 TO 50 DEG FLAP. NOW IT STAYS THE SAME,AT ALL SETTINGS. IT GAVE ME A HEADACHE,, I WASTED ABOUT $40.00 IN HINGES,ARMS,WOOD,ECT.. I HOPE IT HELPS PERFORMANCE..