C172 Weird behaviour during short-field takeoff

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racedude
Airman Basic
Posts: 3
Joined: 29 Mar 2015, 09:17

C172 Weird behaviour during short-field takeoff

Post by racedude »

Hello

For a short-field takeoff, you take off at the minimum speed possible, then stay low in ground effect until you build up speed, and then gently climb out.

When I try that with the A2A aircraft I have a very odd (and reproducible) behaviour. The plane takes off, then I lose complete control while the aircraft makes a sudden movement, then flies in a certain direction for a couple of seconds like on rails (my inputs don't do anything at that moment), then I regain control, then it makes a sudden movement again, flies on rails and I regain control after a couple seconds again. My short clip below shows the issue.

I have noticed this behaviour already in P3D v3 and on multiple installs of P3D v4, newest patch always installed. I usually take off on regular airfields at 70 kts where I have no issues. It's just when taking off at very low speeds.

Anyone experiencing this behaviour too? My realism settings are at the end of the video.

https://www.youtube.com/watch?v=Pe5BLRBTMvs

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Nick - A2A
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Joined: 06 Jun 2014, 13:06
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Re: C172 Weird behaviour during short-field takeoff

Post by Nick - A2A »

Hello racedude,

Do you have a weather engine such as ASP4 installed? From your recording, it looks a bit like the wake turbulence effect is being triggered. In fact, if you fly the same take-off multiple times in quick succession, resetting the aircraft back to the runway in between, it's actually possible for you to end up flying through your own wake turbulence.

Thanks,
Nick

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Lewis - A2A
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Re: C172 Weird behaviour during short-field takeoff

Post by Lewis - A2A »

Just moved topic to tech support. Thanks for the post racedude and the included video, this looks exactly like a weather engine induced movements as Nick mentions.

thanks,
Lewis - A2A
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Oracle427
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Re: C172 Weird behaviour during short-field takeoff

Post by Oracle427 »

Agree with Nick about the weather engine causing a conflict here.

For what it's worth, the technique you are using is for a soft field. You takeoff with the most held up to protect the nosewheel and allow the aircraft to not "plow" into the soft ground and prevent acceleration. One airborne as you said you level of a couple of feet of the ground to accelerate to at least Vx before climbing away.

The short field technique is to hold brakes, apply full power, release brakes and accelerate to rotation speed and then pitch up to Vx.
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A

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