Sort of a general inverted flight question, but specifically about my Turbo Tutor

[BrickPlane]

I've got four flights with the Turbo Tutor under my belt and I've been getting more comfortable. This is my first 3D capable airplane, so I decided to try inverted, since I've gotten comfortable with loops and rolls. I got two mistakes high, then rolled the plane over, then it started nosediving. I gave it full forward pressure which pushed the nose up, but it was still going down at 30° or so. I rolled it back to normal flight and that was that for the flight. I'm trying to figure out why I wasn't able to push the nose up when inverted, when it has enough elevator authority to do a near snap loop. Only thing I can think of is that the plane balances a bit nose heavy. Does a nose heavy plane struggle to fly inverted?

 

[NickRehm]

Might be a little nose heavy, or you might not have enough throw on your elevator when pitching down.

Or what could be happening: if you have your control rod setup to be pull/pitch up, push/pitch down, the control rod may be bending when giving down elevator, leading to not as much pitch-down throw

 

[BrickPlane]

Might be a little nose heavy, or you might not have enough throw on your elevator when pitching down.

Or what could be happening: if you have your control rod setup to be pull/pitch up, push/pitch down, the control rod may be bending when giving down elevator, leading to not as much pitch-down throw

Thank you for the advice. I should have plenty of throw, as the servo is centered and it didn't need much trim, and I'm getting pretty equal deflection up and down.

As far as the servo wire bending, I'm not sure how to rule that out. The tutor has servos mounted pretty far back on the fuselage, so the wires are pretty short.

I'll check CG first and go from there!

 

[Tench745]

You may have needed some more throttle too. Just like when you're upright, if you don't have enough power at a given angle of attack, the plane will sink.

 

[BrickPlane]

You may have needed some more throttle too. Just like when you're upright, if you don't have enough power at a given angle of attack, the plane will sink.

Thank you for responding. I think I was about half throttle, which should be good on 4s. However, I do have a habit of being timid about keeping throttle up through maneuvers, so I'll keep that in mind!

 

[Tench745]

Thank you for responding. I think I was about half throttle, which should be good on 4s. However, I do have a habit of being timid about keeping throttle up through maneuvers, so I'll keep that in mind!

It sounds like you have the basics. Practice and experience will get you the rest of the way. In that vein, I recommend using a simulator when you want to get comfortable with new skills like inverted flight. It's a lot cheaper if you dumb-thumb.

 

[BrickPlane]

It sounds like you have the basics. Practice and experience will get you the rest of the way. In that vein, I recommend using a simulator when you want to get comfortable with new skills like inverted flight. It's a lot cheaper if you dumb-thumb.

Absolutely. It's super weird, I can fly 3D no problem on Realflight, but when I go outside to actually apply it, I get all timid and fly like poo poo.

 

[Merv]

...then rolled the plane over...

When I was learning to fly inverted, it was easier to loop inverted than to roll.

A flat bottom wing is difficult to fly inverted. The high wing with dihedral is also working against you, it wants to fly upright. You will need full throttle and nearly full elevator to be successful. If full throttle and full deflection doesn’t work, try increasing the throws. I’d leave the CG alone, if you are happy with the CG in normal flight, it should work fine for inverted flight.

This plane will fight you all the way while flying inverted. This makes it the ideal plane to learn inverted flight on. When you can hold it inverted and fly across the field, you will have the skills to fly nearly any plane you want.

 

[BrickPlane]

When I was learning to fly inverted, it was easier to loop inverted than to roll.

A flat bottom wing is difficult to fly inverted. The high wing with dihedral is also working against you, it wants to fly upright. You will need full throttle and nearly full elevator to be successful. If full throttle and full deflection doesn’t work, try increasing the throws. I’d leave the CG alone, if you are happy with the CG in normal flight, it should work fine for inverted flight.

This plane will fight you all the way while flying inverted. This makes it the ideal plane to learn inverted flight on. When you can hold it inverted and fly across the field, you will have the skills to fly nearly any plane you want.

Appreciate your thoughts! The plane flew pretty good, but it didn't slow down as much as I thought it should, so I'm willing to see if pushing the CG back helps both that and inverted flight.

 

[Piotrsko]

Cg won't help being inverted much. An airfoil shape on the bottom would, but just flat covering would help some. More down thrust ( it's up thrust inverted), more total thrust to drag it along nose high, more or bigger elevator. Looping into inverted causes problems if you're not high enough to loop out, but you can barrel roll if you have enough rudder authority. Crashing inverted causes more carnage than hitting a fence.

 

[Bricks]

Have you checked your thrust line? A high wing and being a flat bottom wing is a bit tougher inverted.

 

[Merv]

Just to be clear, while I was learning, I would loop inverted and roll out. Usually rolling out before I had intended. My plane a high wing, flat bottom wing with dihedral, in other words a typical trainer plane. It didn’t like being inverted and fought me all the way. But once I gained enough skill to keep it inverted, to keep it from rolling out, I was ready to move on to the next plane, for me it was a war bird.

 

[David Spence]

As an experiment there are 2 things you may want to try. First, try giving it 10-15 degrees positive pitch before you roll over. You (almost) always lose pitch on a rollover in a single engine prop plane so point the nose up a hair before you invert and see if it holds it. Second, try your inversion at 75% throttle, then 80%, then 85% etc. to see if it's an elevator authority issue. The weight of the plane doesn't change regardless of the airspeed but the amount of air passing over the control surfaces does. So if your elevator is struggling to hold you on course inverted then it may need more air passing over it. Hope this helps!