Evening everyone,
I've always wondered where the violent panel shake comes from in the Bo during lift off/initial climb? I've flown that aircraft during various subversions of P3Dv4 and am now close to "new 100 hours" in P3Dv5. While in v4 I had the massive problem of a - in my opinion very exaggerated - nose swing to the left as soon as the main wheels left the ground this behaviour has reduced significantly in v5, I have no idea why. But the panel still shakes violently during TO - and only the panel directly in front of me. I would interpret it as a stall effect if I wouldn't climb normally at 90ish knots. I know the take off dynamics have been a topic here several times and I tried to find an answer but without much luck. So where does that behaviour come from? I cannot recall anything comparable neither in any flightsim model nor in any aircraft I've flown myself or as a passenger. Is that something that happens with a V-tail only?
I use Active Sky and FSUIPC as those addons who COULD imo have to do with it. everything else is much younger so I can exclude it.
Thanks and cheers
Marc
Where does the TO shake come from?
Re: Where does the TO shake come from?
It's a wheel balance issue, perhaps could be made fixable, but seems that it is what it is.
Re: Where does the TO shake come from?
Have you tried braking the wheels before retracting the landing gear?
-Esa
-Esa
-
- Senior Master Sergeant
- Posts: 1658
- Joined: 27 Jun 2009, 03:39
- Location: Southern Germany
- Contact:
Re: Where does the TO shake come from?
Ok that‘s the last thing I would have expected. Nope, I haven‘t, so as long as the wheels are turning it will shake? That would explain why it becomes less shortly after and then stops.
-
- Senior Master Sergeant
- Posts: 2286
- Joined: 05 Nov 2013, 10:48
- Location: Oksboel, Denmark
Re: Where does the TO shake come from?
The shaking is just yet another feature of Accu-Sim I remember a post just after the V35B was released, saying that GA aircraft wheels isn’t dynamically balanced like a wheel in a car, so what you see/feel is perfectly normal. (I’m not a real world pilot)
Kind Regards
Tomas
Sim: FSX SE
Accu-Sim aircraft in my hangar:
C172, C182, P51 Civ, P51 Mil, B17, Spitfire, P47, B377 COTS,
J3 Cub, T6, Connie, P-40, V35B
A2A Accu-Sim Avro Lancaster Loading:............0.000003% complete, please wait.
Tomas
Sim: FSX SE
Accu-Sim aircraft in my hangar:
C172, C182, P51 Civ, P51 Mil, B17, Spitfire, P47, B377 COTS,
J3 Cub, T6, Connie, P-40, V35B
A2A Accu-Sim Avro Lancaster Loading:............0.000003% complete, please wait.
- Nick - A2A
- A2A Captain
- Posts: 13805
- Joined: 06 Jun 2014, 13:06
- Location: UK
Re: Where does the TO shake come from?
Yes, this was behaviour that Scott noticed in the real aircraft while performing flight tests and decided to simulate. A little tap of the brakes just after the wheels leave the ground should stop the shaking.
Incidentally, the reason why it's only the section of panel directly in front of you that moves around is because this part is the shock-mounted 'floating panel' which helps protect the sensitive gyro instruments from vibration.
Thanks,
Nick
Incidentally, the reason why it's only the section of panel directly in front of you that moves around is because this part is the shock-mounted 'floating panel' which helps protect the sensitive gyro instruments from vibration.
Thanks,
Nick
A2A Simulations Inc.
- Ron Attwood
- Chief Master Sergeant
- Posts: 3254
- Joined: 30 Nov 2010, 10:07
- Location: Chelmsford, Essex, UK
Re: Where does the TO shake come from?
That was only recently pointed out to me by one of the beta testers. I smile every time now. Lovely touch.Nick - A2A wrote: ↑13 Nov 2020, 06:09 Yes, this was behaviour that Scott noticed in the real aircraft while performing flight tests and decided to simulate. A little tap of the brakes just after the wheels leave the ground should stop the shaking.
Incidentally, the reason why it's only the section of panel directly in front of you that moves around is because this part is the shock-mounted 'floating panel' which helps protect the sensitive gyro instruments from vibration.
Thanks,
Nick
Eva Vlaardingerbroek, an inspiratiom.
-
- Senior Master Sergeant
- Posts: 1658
- Joined: 27 Jun 2009, 03:39
- Location: Southern Germany
- Contact:
Re: Where does the TO shake come from?
Hmkay... it seems pretty exaggerated to me. That‘s a 8‘‘ diameter after all, not 18‘‘. The fearing on the front wheel of our club‘s 172 used to buffet in the air stream which led to vibrations of the pedals. But I‘ve never felt anything because of rotating wheels. Anyway, I can live with that knowledge, at least I don‘t think it‘s a stall anymore
Thanks guys!
Thanks guys!
- DHenriques_
- A2A Chief Pilot
- Posts: 5711
- Joined: 27 Mar 2009, 08:31
- Location: East Coast United States
Re: Where does the TO shake come from?
Just something to remember;
Not all aircraft require a brake tap or brake use OF ANY KIND after rotation with the gear either before or while in transit. Most large airplanes such as airliners use scrubbers and other means to stabilize the wheel rotation as the gear retracts.
The P51 for example, has a notation in the Dash 1 that actually tells you NOT to use brakes after takeoff due to high wheel speeds vs heat transfer.
It's worth noting that heat transfer is the universal issue with any use of brakes on an airplane.
The bottom line on this is that before doing it pilots are encouraged to check their flight handbooks for notation pro or con on ANY aircraft being flown.
Dudley Henriques
Not all aircraft require a brake tap or brake use OF ANY KIND after rotation with the gear either before or while in transit. Most large airplanes such as airliners use scrubbers and other means to stabilize the wheel rotation as the gear retracts.
The P51 for example, has a notation in the Dash 1 that actually tells you NOT to use brakes after takeoff due to high wheel speeds vs heat transfer.
It's worth noting that heat transfer is the universal issue with any use of brakes on an airplane.
The bottom line on this is that before doing it pilots are encouraged to check their flight handbooks for notation pro or con on ANY aircraft being flown.
Dudley Henriques
Re: Where does the TO shake come from?
Yeah, the most common scheme in airliners is a pair of friction pads in nose wheel well, and an automatic application of hydraulic wheel brakes on gear retraction. The puff of brake dust is sometimes clearly visible when the gear is selected up.
-Esa
-Esa
- DHenriques_
- A2A Chief Pilot
- Posts: 5711
- Joined: 27 Mar 2009, 08:31
- Location: East Coast United States
Re: Where does the TO shake come from?
The fastest ground speed I've ever experienced at rotation on takeoff would be the T38. At normal gross weight that would be around 160 knots.
The Talon is definitely a "don't touch the brakes after rotation" airplane. If you do the next landing should require a runway from New York to Chicago. LOL
Dudley Henriques
Re: Where does the TO shake come from?
Certainly varies from aircraft to aircraft, sure. The closest to that one I'm familiar with would be the F/A-18. It automatically brakes the wheels on retraction as they don't have quite enough room to keep spinning in their bays, and probably to avoid gyroscopic forces during the retraction as well, as the main gear is mechanically rather complex in that type.
-Esa
-Esa
- DHenriques_
- A2A Chief Pilot
- Posts: 5711
- Joined: 27 Mar 2009, 08:31
- Location: East Coast United States
Re: Where does the TO shake come from?
Yes, the Hornet's gear system was designed by twelve insane engineers that management locked in a windowless room and denied them food and water for 30 days straight. I believe the same crew engineered the gear on the Cessna 210. LOLAKar wrote: ↑13 Nov 2020, 09:38 Certainly varies from aircraft to aircraft, sure. The closest to that one I'm familiar with would be the F/A-18. It automatically brakes the wheels on retraction as they don't have quite enough room to keep spinning in their bays, and probably to avoid gyroscopic forces during the retraction as well, as the main gear is mechanically rather complex in that type.
-Esa
DH
Re: Where does the TO shake come from?
Except that the Hornet's is a sturdy one - when it's within the tolerances and works!
Landing incidents resulting in runway a excursion at worst due to planing link not locking were not... entirely impossible, I recall. Perhaps that's why they threw a proxy switch for the very purpose of monitoring the workings of those linkages!
-Esa
Landing incidents resulting in runway a excursion at worst due to planing link not locking were not... entirely impossible, I recall. Perhaps that's why they threw a proxy switch for the very purpose of monitoring the workings of those linkages!
-Esa
Re: Where does the TO shake come from?
Some 172s and 182s I have flown have a brief but noticeable vibration after liftoff. The mains and the spring struts all start to wobble together and it magnifies the sensation. When I flew as a backseat passenger for the first time I watched the mains and was surprised at how much the spring struts wobbled due to the wheel rotation.
Edit: correct sprint struts to spring struts and corrected sprint gear to spring struts.
Edit: correct sprint struts to spring struts and corrected sprint gear to spring struts.
Last edited by Oracle427 on 13 Nov 2020, 18:55, edited 2 times in total.
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A
N28021 1979 Super Viking 17-30A
Who is online
Users browsing this forum: No registered users and 37 guests