Redbird Posted June 25, 2020 Share Posted June 25, 2020 As my 'Great Wall' glider has thick tails I am thinking of fitting 8mm servos into the fins at root to drive existing balljoints for elevators. I know I will need more weight in the nose and that overall it will be heavier but what is the verdict on having more weight in the tail for F3F? is there really much of an inertial penalty do you think? Servos are about 10gms each plus the wiring which will be 2 x thin twin flex. Link to comment Share on other sites More sharing options...
oipigface Posted June 25, 2020 Share Posted June 25, 2020 2 minutes ago, Redbird said: is there really much of an inertial penalty do you think? Yes. 1 Link to comment Share on other sites More sharing options...
Redbird Posted June 25, 2020 Author Share Posted June 25, 2020 Thanks John, I take it that lighter tails will whip round quicker then. Link to comment Share on other sites More sharing options...
wookman Posted June 25, 2020 Share Posted June 25, 2020 I would put the servos in the front. You will notice the extra weight away from the cg. It is not just about all up weight. If the tails are thick enough to swallow 8mm servos it's not going to be all that quick anyway is it? 1 Link to comment Share on other sites More sharing options...
Redbird Posted June 25, 2020 Author Share Posted June 25, 2020 Cheers Wookman, it is flying with servos in nose I just like the idea of more direct action and wonder about the consequences. Do you think thick tails will really hold it back? Link to comment Share on other sites More sharing options...
Phil.Taylor Posted June 25, 2020 Share Posted June 25, 2020 2x10g + 50-60g extra noseweight Not sure what you gain? - worth doing if going electric Inertia effects on pitch axis - yes but probably not noticeable unless doing extreme square loops. Phil. 2 Link to comment Share on other sites More sharing options...
wookman Posted June 25, 2020 Share Posted June 25, 2020 More frontal area is going to mean slower aeroplane. Just look at a PB2 fuselage to see how seriously that is taken. Link to comment Share on other sites More sharing options...
Redbird Posted June 25, 2020 Author Share Posted June 25, 2020 2 minutes ago, wookman said: More frontal area is going to mean slower aeroplane. Just look at a PB2 fuselage to see how seriously that is taken. Yes, unfortunately this fuse is also fat! Phil, I suppose response time from reduced linkage length ought be negligible and unless there is some advantage to having a longer pitch moment then nothing to be gained apart from space up front. Hmm. Link to comment Share on other sites More sharing options...
Kyri Posted June 25, 2020 Share Posted June 25, 2020 When I got the needle in bits the fuz was broken and so were the pushrods, so I ended up putting servos in the tail. Whilst it is better to have the weight around the cg where possible, I have a long way to go on piloting before servos in the tail become an issue! It can make for a really slop free arrangement, although a properly setup pushrod system can be too. 1 Link to comment Share on other sites More sharing options...
Andy_B Posted June 25, 2020 Share Posted June 25, 2020 32 minutes ago, wookman said: More frontal area is going to mean slower aeroplane. Just look at a PB2 fuselage to see how seriously that is taken. I dont think its that simple ....a thicker tailplane may give you more lift and better control in the corners , its not good going ultra fast on the straights and loosing all that at the ends more to be made by cornering well and keeping the speed up jm2c 1 Link to comment Share on other sites More sharing options...
wookman Posted June 25, 2020 Share Posted June 25, 2020 Aerodynamics is never that simple, but as a rule of thumb skinny is quick when it comes to fuselages because it's just holding the clever bits that do the flying in the right place. 1 Link to comment Share on other sites More sharing options...
oipigface Posted June 25, 2020 Share Posted June 25, 2020 3 hours ago, Redbird said: Thanks John, I take it that lighter tails will whip round quicker then. They stop whipping round quicker as well, Bruce! 1 Link to comment Share on other sites More sharing options...
Redbird Posted June 25, 2020 Author Share Posted June 25, 2020 Yes, which is equally important. That did dawn on me. Then again we mostly focus on applying the force rather than taking it off and so the duration of (more or sooner) ele up would be less with more momentum at the rear. Hmm again. Link to comment Share on other sites More sharing options...
isoaritfirst Posted June 26, 2020 Share Posted June 26, 2020 agree with the above comments, but maybe also for consideration; If you fly predictable smooth turns then set up into and out of the turn is more important than lightning quick snappy servos/light fuselage appendages. Less versatility of course, but damping down may just help some fliers. 4 Link to comment Share on other sites More sharing options...
Redbird Posted June 26, 2020 Author Share Posted June 26, 2020 Thanks Mike I wondered what you'd say. I am still exploring aft cg on this glider and out shortly for more testing. Link to comment Share on other sites More sharing options...
isoaritfirst Posted June 26, 2020 Share Posted June 26, 2020 1 hour ago, Redbird said: I am still exploring aft cg on this glider and out shortly for more testing. D- aft cg. Be careful out there... Link to comment Share on other sites More sharing options...
Redbird Posted June 26, 2020 Author Share Posted June 26, 2020 Ha, careful, yep. It is extremely benign and I have discovered floaty. I don't know how fast it is though, only had it moving once, but it did accelerate very well. I have gone far enough with the cg aft to know turns are no longer improving and moving forward again a little has given it back some much need pace. Servos in the tail may be something to try when I have properly put it through its paces. Link to comment Share on other sites More sharing options...
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