I recently completed a refurb on a 96" Ikon West Monocoupe. For reasons still unknown to me I decided to install flaps. On the second flight I decided to drop the flaps to see what would happen ( I was at a safe altitude), to my suprise the nose dropped.I have tried it several times in different wind conditions with no change in results. Is it possible this is the result of the plane being nose heavy?
Any thoughts on the subject would be greatly appreciated.

Thanks and regards
A3

When you drop the flaps two things occur. First is that you drastically increase the camber value of the airfoil over the span with the flaps. That is going to strongly affect the negative pitching moment of the wing. If the tail is not sufficiently big enough you can get a neutral or pitch down effect instead of a nose up effect as would normally be expected by the associated shift in the effective wing incidence.

The second is that the model slows down SO quickly when you deployed the flaps that the nose up effect was over before you noticed it and the model's trim caused it to nose down to get back to flying speed. How and when you lower the flaps would determine that.

What sort of flaps you built into the model will also make a difference. Plain flaps, which look like ailerons, would typicaly cause a radical gain in lift both from the increase in camber and effective wing incidence. On the other hand a split flap, such as you'd get with a lower surface only slab of plywood added to the normal wing, will provide mostly just drag and a spoiler like effect.

When you deploy flaps, you will almost always induce a nose-down pitching moment for the WING. As a pilot, you don't care (and really can't tell) if you induce a nose-down pitching moment for the wing. What you care about (and what you can see) is whether flap deployment induces a nose-down (or nose-up) pitching moment for the AIRCRAFT.

If the induced pitching moment for the wing is almost always nose-down, how can the induced pitching moment for the aircraft be nose-up? In most instances where this is the case, flap deployment creates a downward component to the air approaching the elevator/horizontal stabilizer/stabilator. This causes the elevator/horizontal stabilizer/stabilator to push down more (or possibly push up less) and the NET result can be an AIRCRAFT that wants to pitch up with flap deployment. For certain geometries (like T-Tails) flap deployment tends to have little influence on the flow over the tail and the effect of flap deployment is typically nose-down. For other geometries (like a T-38 with closely spaced flaps and stabilator) the effect can be strongly nose-up. So you can look at the gemerty of an aircraft and predict what you might see, but it's possible for the aircraft to pitch either direction with flap deflection.

Actually, my experience with Monocoupe flaps is that they are very ineffective, without much pitch trim change at all. Just how different airplanes react can be seen...I have Sicroly and Curare, which both go nose up with flap deflection, and quite markedly so. My 190 has minimal trim change, nose very slightly down. And I'll bet others will have the same aircraft with different reactions. I doubt that balance location has much to do with it, my full size experience (limited) was that I had to trim nose up with flap deflection (ie airplane went nose down) to maintain circuit and approach speeds, so even in the full size world, different A/C will exhibit different responses. The biggest effect on flap response is probably airspeed, for Curare, as above, if the speed is a bit high nose goes up, bring the revs down and as the model slows the nose goes slowly down. Something to try, anyway.
Evan, WB #12.