This may seem like a silly question, especially flying warbirds for years but here goes. What is the proper way to trim the elevator when you lower your flaps, up or down or is it neccessary?
Larry

I'm not a big warbird guy...so take this with a grain....

but anytime I have had a plane with flaps.... I don't use "trim" I use mix in the radio.... as flaps are applied, a bit of down elevator is mixed in to counteract the increased lift....

I just set up a basic mix, take the plane up high... apply the flaps and see what happens, then I adjust the mix as needed.....

I made a mistake, but your answer was what I was looking for. I meant "mix", not trim. On a Zero I have, I installed flaps, mixed some down elevator and off I went. When it came time to land with flags deployed, the plane came in slighty nose down, so I had to much down elevator and I had to really get on the up elevator to get it in. What I didn't see was the "increased" lift with flaps. Next time I won't mix in to much down elevator and see what that does or just don't mix anything at all.
Larry
PS Another possibility was I didn't come in fast enough or under enough power.

that would be good.....

no mix... take it up high... apply flaps.. see what happens... adjust accordingly


Trying out new mixes close to the ground or on a final approach is not good for our hearts!

Boy, is that true.

Hey Larry,

I usually start with about a 5% mix on the elevator. Depending on CG and other factors this may be too much or not enough. I have used this with a couple of Mustangs and it was spot on.

The three-mistake high rule applies here, and try to be at approach speed when trimming!! But there is NO set rule for predicting whether up or down elevator trim may be required-just do as the man says. On a Heinkle bipe, lowered flaps requires up elevator trim; low wing war birds generally require down elevator trim to counter the added lift due to flap deflection-do like the big planes do-fly and find out.
hookemut

I have found that it depends upon the plane. Some of my warbirds will climb when flaps are deployed (Meister ME 109), while others will not (spitfires and hurricanes). So, my practice has been to not use any mix at first and see how the plane reacts and then make manual trim adjustments to compensate. Once I know how that flaps affect the plane, then I start with a little bit of mixing (a few percent, such as 3-5%) and slowly increase from there.

Right ON,
That's what I've been finding. I have two planes with flaps, and both react differently. One plane is a Pica FW 190 and the other a Top Flite Zero. My mistake was mixing in an unknown percentage of flap/elevator and getting some strange reactions when making a final approach. What I have been doing was, forget the flaps and come in under power until the wheels are about to touch down, then cut throttle so I guess my next question is, is flaps worth the extra weight and trouble. I would say they make next to no difference, just look cool.
Larry

The question of whether not its worth it varies from plane-to-plane and from pilot-to-pilot. On some planes, the flaps don't do very much and are more for asthetic appeal. On other planes, they are very functional and can be very helpful on landings. For example, on the GSP Spitfire that I had, the flaps were not split flaps and were small, so they didn't help a lot on landing. Many people with this plane preferred not to use them at all because they often made landing more difficult. On the other hand, I think most modelers with a Yellow Spit would recommend using the flaps (depending upon the wind) to slow the plane down for landing and prevent overshooting the end of the runway. On my KMP Hurricane, they are very effective in slowing the plane down and allow a steeper approach, so I always use them on landings. On my Meister ME 109 (102"), the flaps are relatively small, but they do help slow the plane down so I use them on landing, especially in calm conditions, even though with the Meister wing the plane can be landed without them.