V-Speeds

[Dan Michaels]

Re: V-Speeds

That's manuevering speed - 105

105 is criuse speed in normal conditions ie. some moderate turbulence day to day flying. Between that and VNE would be cruise in Clean air (caution range) you must be below your manuv speed in anything over small bumps or moderate turbu.

105 is recommended cruise unless you are in the bumps. Your life depends on what you think a damaging bump is.

Dan

[flyguy]

Re: V-Speeds

I am begining to think that 105 is max structural cruise and about 85 or so is manuvering speed. IF: the BC12's MS is in the same range as the F21.

That is you can produce more stress on the aircraft with the controls at a slower speed, before it will stall, than a "standard" gust would produce at a higher speed. "Standard" being whatever value the FAA and the manufacturer used at the time of manufacture.

Note my Cessna 150 handbook gives Max structural as 120 MPH and Manuvering speed as 109.

Will the wings always break first, or can the tail go first in these situations? Wonder if anyone knows? I always figure just outboard of the outboard strut attach point.

EDIT: Forrest? Where are you?

EDIT 2: Is there a number somewhere of how many G's a stock BC12 will tolerate safely? Anyone know?

Re: V-Speeds

Darryl,

I'll go look into my literature and see if I can find further explanation as how I know that. I see it is not obvious why that it is as I said, however I am quite certain it is correct. Dave

Re: V-Speeds

Anyone have any idea on why the number 105 for level flight? What is that all about? What was Taylorcraft trying to say with that number?
Darryl

That's manuevering speed - 105

[flyguy]

Re: V-Speeds

Anyone have any idea on why the number 105 for level flight? What is that all about? What was Taylorcraft trying to say with that number?
Darryl

Re: V-Speeds

This snippit is from the tcds of a bc12d;

Airspeed Limits Landplane:
(True Indicated)
Level flight or climb 105 m.p.h.
Glide or dive 140 m.p.h.
Seaplane: Level flight or climb 95 m.p.h.
Glide or dive 129 m.p.h.

Manuevering speed is in blue.

Look up your model in the tcds to find your manuevering speed.

I recall that it is also listed on the operating limitations form that is required to be in the ac when operating.

Dave

[flyguy]

Re: V-Speeds

From that info it looks as if anything under 85 MPH would be ok for the 1200 lb. birds.
DC

Edit: I meant for manuvering speed.

[dennispip]

Re: V-Speeds

Manuevering speed for F19 is 87MPH at 1500# and 86MPH at 1280# or less.
F21A is 87/86 at 1500#/<1380#.
F21B is 93/86 at 1750/<1380.

I can't find anything or earlier birds. I think that 80/75 would be a good range depending on load. You can always go slower and be safe if it gets rough and let it stall rather than break.

[DanBrown]

Re: V-Speeds

For me, I'd much rather recover from a stall than a broken airplane. I've been in turbulence that suddenly added 50 knots to the IAS -- scarey when that pushes you over Vne. And then you may have to recover from an unusual attitude. So in an old light pre-war tcraft, I'd rather be on the low side of 80 rather than over that in the moderate to severe stuff.

[Dan Michaels]

Re: V-Speeds

My understanding of the "manouevering speed" is that at which single full control deflection will not cause structural damage. Nothing to do with stall speed.

Is this not what the "yellow arc" on later-certified aeroplanes demarks?

Yellow mark is caution area. Smooth air only no sudden moves. Top of the green is usually recommended cruise. M/S is a speed at which the wing will stall before struct damage will occur. M/S is a speed you would use in turbulence. It is not depicted on the ASI for reasons posted before, I think it should be for the reasons we see in this thread (No one seems to know it).

Dan

[Marv]

Re: V-Speeds

I do not know where i got this but i beleive the rouugh air maneurvering speed is 85 mph. Marv

[flyguy]

Re: V-Speeds

I wasn't thinking of control usage, but rather rough air overstress resistance. Abusing the controls I can avoid, not so with turbulence. I think I may have missed the concept on level= 105 max but glide or dive to 140 is "OK."
DC

[N95334]

Re: V-Speeds

My airspeed is marked: green arc from 40 mph to 105mph then yellow from 105 to 140 where the red line is. Remember something in the operating book not to exceed 105mph in level or climb, don't understand that one though.

[Mark Julicher]

Re: V-Speeds

Rob,
You have it exactly correct.
Va is the speed where abrupt full control deflection will not cause structural damage. You can also think of it as the speed where a sudden sharp edged gust (think updraft) will cause a stall rather than snap the spars.

I would not ever want to pop the yoke full forwards or full aft at 100 indicated. I believe it would exceed the utility G limits, although I have never tried it and would be afraid to do so. I use 80 in moderate turbulence also.

[Robert Lees]

Re: V-Speeds

My understanding of the "manouevering speed" is that at which single full control deflection will not cause structural damage. Nothing to do with stall speed.

Is this not what the "yellow arc" on later-certified aeroplanes demarks?