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-   -   Tilts to right? (https://www.rcuniverse.com/forum/rc-helicopter-beginners-forum-165/11593954-tilts-right.html)

Hedgewarden 01-28-2014 03:48 PM

Tilts to right?
 
I have a Propel SpeedStar (reskinned and rebranded V911) and a Hubsan Lynx - both FP 4ch. I noticed that both tilt slightly to the right when viewed from behind, when hovering or moving straight forward. Is this normal? (slightly degrades the realism of the Lynx, and tilts the video.)

My guess is that it is normal, and is caused by the tail rotor thrust. While the tail rotor thrust balances the yaw of the main rotor, it also may provide some rotational thrust in the roll direction if it is centered below the center of lift.

Thoughts please:confused:

karlik 01-29-2014 01:01 PM


You are kinda correct about the tail rotor - it's called translating tendency.

Read all about it here - http://helicopterflight.net/translating_tendency.htm and here http://www.helicopterpage.com/html/forces.html

That second link is my favorite. The home page is http://www.helicopterpage.com/index.html and belongs to Glenn Bloom, an Army heli pilot. He makes complicated stuff uncomplicated, adds some real life examples and a bit of humor.

Hedgewarden 01-29-2014 04:15 PM


Originally Posted by karlik (Post 11723521)

You are kinda correct about the tail rotor - it's called translating tendency.

Read all about it here - http://helicopterflight.net/translating_tendency.htm and here http://www.helicopterpage.com/html/forces.html

That second link is my favorite. The home page is http://www.helicopterpage.com/index.html and belongs to Glenn Bloom, an Army heli pilot. He makes complicated stuff uncomplicated, adds some real life examples and a bit of humor.

Thanks, Larry.
Excellent explanation. Yup, I was only "sort of right". Very glad to know the tilt is normal. Amazing how a 9 inch model so accurately reflects real heli physics.
-Howard

BarracudaHockey 01-30-2014 06:22 AM

Weirdest thing ever happened to me, I started flying a Vario which has right hand rotation like the full scale, and it tilts to the left. Took me forever to get used to, I kept trying to "correct" it.

karlik 01-30-2014 01:04 PM

I was going to ask if Howard spotted the difference between his 9 inch model and a real one.
I'd say there's at least an 80% chance I would have the put the blades on backwards.

Does it throw you to switch back to a "normal" heli now?

Hedgewarden 01-30-2014 08:16 PM


Originally Posted by karlik (Post 11724452)
I was going to ask if Howard spotted the difference between his 9 inch model and a real one.
I'd say there's at least an 80% chance I would have the put the blades on backwards.

Does it throw you to switch back to a "normal" heli now?

I haven't verified the rotor rotation v. tilt directions - I assumed a tail rotor on the right hand side was pushing toward the left. As for the full size chopper - i have been carefully testing that, but only in MY DREAMS. ;)

I guess there may be a puzzle being offered by your question, Larry - since I am a 1 month old noob (whoosh, over my head?). I'm still happy if I crash the SpeedStar (aka V911) fewer than 3 times on a 6 min battery charge. Still sorting it out. I can't fly my quad kite on windless days, so I thought I'd add an alternative "flying" obsession to try to slow the decline of my 71 year old eye-hand coordination and reaction times.

Early observations - many similarities besides putting objects into the air (flying - yeah!) Quad kites require subtle control using essentially 4 channels (tension and movement of 4 direct lines). Kite is generally less hectic (after 4 years of practice anyway!) Kite also provides, besides visual feedback, tactile feedback through the lines - which I miss in the choppers. But the choppers provide plenty of challenge and exercise, and have a 3 dimensional freedom of movement, v. 2D for the kites.

Currently am focusing on gaining serious competence with FP choppers in 100 to 250 size. Then, there will be the challenge of actual FPV flying with the Hubsan Lynx. Maybe some day, a 250 CP size might be in the bucket list. Unlike some of the young flyers I see posting ("I got a CX last week, mastered it, am bored, which 700 size CP should I get next"), I am in no hurry to challenge the xtreme-trick fliers.

Thanks for the info and links,
-Howard

karlik 01-30-2014 11:03 PM

When you mentioned how our RC stuff "reflects real heli physics" I just wondered if you caught one of the subtle differences.
Yours ( and most rc stuff) leans to the right. On a real, or full scale heli the main rotors spin in the opposite direction so the thrust from the tail rotor is reversed and they lean to the left (at least here in the US). Not really important and won't have ant effect on your learning curve.
My FP still flies, and I take it almost every time I go out. The sight and sound of the 450 still intimidates me and I know a repair will be much more expensive so I'm just more confident with the FP.

BarracudaHockey 01-31-2014 06:26 AM

Some full scale have a slight tilt built into the main rotor to compensate so that the fuselage is level in a hover.

Hedgewarden 02-03-2014 08:29 AM

OK, Larry.
In the back of my mind, I had a subtle unvoiced idea that I aught to check the tilt v. rotation direction - the little guys are coming from a former British colony. :p
But I never acted on it, so I think you caught me.

For the foreseeable future, I'll probably stick with FP, because their characteristics seem closer to full scale choppers. Try to build a fleet with a lot of 200-250 size, look for more 1/43 scale 4 ch models.

Concentrate on smooth, precision flying. Try to get my counter-clockwise coordinated circles somewhat close to my clockwise. (I guess that is another side effect of the torques and tail rotor thrust. Coming out of a clockwise turn, the little guy wants to continue forward, out of the counter-clockwise turn, it wants to drift backward.)

Andy - I was wondering if any full scale choppers tried to compensate for the tilt. Good info.:)

-Howard


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