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Telecaster incidence problem

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Old 12-25-2016, 06:31 AM
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discusmike
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Default Telecaster incidence problem

Hi guys I have a stick built telecaster with a +wing incidence of 4 and stab incidence is the same,the plane is supposed to have a wing of plus 41/2 and stab of 2,the plane flies fine in level flight but wants to take off to soon and will go into a straight vertical hover like a 3D plane when doing loops,I really don't want to tear the stab off,is there anyway to remedy some of this?thanks and merry xmass
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Old 12-25-2016, 06:31 AM
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That's telecaster sorry
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Old 12-25-2016, 06:32 AM
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My phone is auto correcting, telemaster.
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Old 12-25-2016, 08:56 AM
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You could correct the decalage by shimming the wing (leading edge), but I'm not sure what the real problem is. Sounds like you have too little elevator authority.
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Old 12-25-2016, 09:00 AM
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Merry Xmas Mike, Ah ha had me guessing what a telecaster was. Guessing agine that what you have is the Senior Telemaster, wonderful airplane. I keep an old Arf version on hand for the occasional student as well as earning it keep as a glider piggyback launcher. I even built one in the past with six 25 glow engines, that was a kick.

Are you sure that you have a incidence problem especially since you say that your airplane trims out nice for level flight? I have my doubts, which brings us to an important question for you and that is did your build yours with the standard banded wing??

The reason this is important is it is very common when loops are done with insufficient rubber as the stick increases the 'G' load the leading edge of the wing will lift up and this cause sudden and unexpected pitch up. This seems very likely given the loop attempts you described.

The early takeoff and pitch up is common if the pilot does not hold the airplane down after takeoff and this is quite normal with a Telly. This especially so if the airplane was trimmed to a slow approach on the prior landing and trims not reset before takeoff.

Just a few of my thoughts

John
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Old 12-25-2016, 07:32 PM
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The wing is bolted on,not a two piece wing,would incorrect thrust line cause this?
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Old 12-25-2016, 07:41 PM
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Once I'm in the air the tele flies well,lands well,just the loop issue
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Old 12-26-2016, 03:29 AM
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Frankly, I don't really understand what the problem is. I believe to understand that you have wing and stab at the same incidence (that is zero decalage) and that you can't change that easily.

Now, if you observe (on the one hand) that the model is fine in level flight and (on the other hand) it pitches up into a hover when a loop is tried, then I think it's balanced quite rearward (to match zero decalage) and it's actually unstable. So when it gets over a certain point (only a bit pitch up) the pitching-up is self-energizing. I wouldn't think that could be corrected with down thrust, but only with a more forward C/G.

The reason why I think so is that a Telemaster has flat-bottom wings (and even stab, for that matter) which have a strong down-pitching moment not depending on lift but on airspeed squared. You might have found a "sweet spot" (by chance) for level flight where all is balanced. At lower speed (take-off, loop) the down-pitching moment is lower and the airplane rears up.

If that is the case, more decalage (and the corresponding more forward balance) is mandatory. Since the stab is fixed I would just think of shimming the wing, regardless of bolted or strapped on. Just my thoughts...

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Old 12-27-2016, 07:24 AM
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A plane that takes off before you want it to has the wrong landing gear set up. If it's a tricycle gear, put bigger main wheels or a smaller nose wheel on.

On the loop problem, are you saying that you can't pull it the rest of the way over the top of the loop? So the plane does the first 1/4 of the loop fine, then just goes vertical and won't pitch anymore?
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