The reason for using the thinner elevator, was o soften the controls around nuetral. It does work, but, if you think about it, comes with a price. It also softens up the intersections of the eights. This is modt notably seen as a small flat spot at the intersection.

Using an elevator that starts out at the same thickness goes give more sensitivity at nuetral, but, also helps with the intersections.

Many designers today have begun to use thrust, and stab incidences to correct for the problems that using a thinner elevator is trying to compensate for. These are better solutions, IMHO,

In the case of equal stab and elevator thicknesses, the issue shown in your illustration, is very minor. If the elevator is tapered and then has the 45 degree leading edge installed, you may notice that the actual dimension of the high point of the elevator, is slightly smaller than the stab, which usually takes care of what your illustration shows.

Thanks Guys, I was hoping to hear from someone that has built Avanti's, so this is great. I do know about the thinner elevator being an attempt to soften the elevator at neutral. I also have a copy of Dave fitzgerald's old article called "De-tails" where he tested plenty of stab/elevator configs on his first Star Gazer that had a hunting problem. I've seen Dave fly his Thunder Gazer as well, so I'm sure that the model design is good.

I was just curious to see some more comments on this sort of thing. Getting any stunter to groove and fly nice round loops is always a challenge, so it's always nice to hear from the experts.

Keith R

One airplane with 5 mm slack at elevator T.E. wouldnt groove with slack removed .
Resloping to 3 . 5 mm improved it but inadequate . Tho C.G. was 3/4 rear of plan posn for that wing . . .

Flap movement afore elevator effectiveness , effectively meand wing alters A.O.A.
The T.E. of the flap going down raises A.O.A. etc .

This plane was flown in wind a lot , the pitching or balooning into wind , and dropping downwind was most
noticable with the slop removed , basically it'd ossilate and overcontrol .

Seeing I'd been flying it for 6 months ( 100 Flights ) prviously with no flight / control issues
before Id got motivated to ' repair ' the sloppy fittings ( Light bike spokes used for dual horns )
It proved out ' the theory ' Particularly when two weeks latter I dissasemble it and reamed out
the horn bushes Id Fitted . After reinstallation one horn had tightened up a bit. So 3.5 one side ,
5 mm the other .

When there was a good steady breeze trying to push the marginally powered plane about , the effects
became abundantly evident .I waited for the slack to increase ( the angled spoke end at the head was responsable .  0 It Didnt . 

Had been using FSR 25 clone , threw a OS 35 in to pull C.G. Fwd .

It was a lighter steering more accurate plane with the equvilant of the ' dead zone ' functioning .
My presumption is that the small subconcious corrections for wind , with the altering of wing lift
compensateing, give much smoother flight .

Same plane , same C.G. , same engine , etc , was a touchy pig of a thing in comparison,
Would not ' point ' and ' groove ' as it had earlier , noticable particularly in manouvres
with the coastal sea breeze in the sailing season
makeing flying a irratateing and fustrateing waste of time .
You can immagine how P'd off I was after correcting back to ' almost as was ' provided
provided further exercisses of marginal accuracy under all conditions .

Also allignment of both elevators provided evidance of roll moment induced by unequal centering .

So , I presume C.G. and the dreaded slack zone are directly related .  ' Nothing but FUN . ! .