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Dora nose wobble at minimum speed


Eros
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Hello all,

 

I put the Dora in a "Slow flight - Minimum Controlled Airspeed" (with full flaps down) configuration:

remain straight and level by keeping the attitude appropriate to keep the airspeed at the minimum + power setting to keep the VSI steady at 0.

Then the aircraft starts to wobble and the nose initiate a right rotation around it's longitudinal axis.

I'm guessing due to p-factor but wobbling like that seems weird.

Is it suppose to be doing that?

 

I could upload a video showing it later if required.

335th_GREros

 

[sIGPIC][/sIGPIC]

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He's talking about an effect, which I also think is directly related to the way DCS models p-factor, and affects also the p51d, specially after takeoff at high power settings at low speeds and a notch of flaps.

 

It's also present if you engine simply quits, your prop doesn't windmill, and you start a steep descent, or a 90º dive... You will be able to see that wobbling too.

 

The less wobbly is still the K4.

 

I feel it must be overdone, but I have no way to prove... numerically... so, no valid argument to present to Yo-Yo :-/

 

Of course you have not :) because nobody can confess that he performed steep diving with a stopped prop...

 

And returning to the discussion of deflected downwash... some days ago I had an opportunity to feel it with my skin. The parking slots of the Mustangs were just perpendicularly to the wind that was about 15 knots and the downwash of the plane performing pre-shutdown engine run was significantly deflected.

Later I discussed this effect with Nick Grey and he told that this effect (counter weathervane) is clearly pronounced at TO with flaps down because of the reason I told you before.

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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Interesting Yo-Yo, but I am almost surely not significative enough to overcome the weathervane tendency, as it was initially modeled a few version ago, right ?

 

 

No, we did not change anything regarding the side deflection for a years. Since early 2012 when the Mustabg was ready.

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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So then is it better to take off in the Dora with flaps UP to get a more stable climb

up until you raise your gear ???????

 

That is what I get out of this, but I know nothing about the physics and terms

many of you mentioned.

 

Thanks for your answer to this !

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So then is it better to take off in the Dora with flaps UP to get a more stable climb

up until you raise your gear ?

 

Yes. For most prop aircraft, flaps-up takeoffs are recommended unless the runway is short. You get into the air faster with flaps, but it's less efficient, so you'll be higher after a minute of climbing if you didn't use flaps.

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