V-Speeds

[fearofpavement]

Re: V-Speeds

I have flown a pretty extensive variety of aircraft and have never known one to have the maneuvering speed marked on the airspeed indicator. I think one reason for this is that many V speeds are calculated for max gross weight and since maneuvering speed decreases as the weight decreases, safety margin would decrease with reduced weight rather than increase as with the other speeds typically indicated on the instrument. Although I have seen many aircraft with only one maneuvering speed posted. (and others have a few different speeds for different weights...)

[astjp2]

Re: V-Speeds

There are no published speeds like manuvering, so you should not try and mark them, the only one is the VNE the rest are complied with by placards. Tim

[Robert Lees]

Re: V-Speeds

I have always had 100 statute in my head as manuvering speed for the BC12D, is that correct?

Personally I use 80.

[flyguy]

Re: V-Speeds

I think you are correct that 80 is a more reasonable value for manuvering speed as at 100 that wing is going to pull a lot of G's before it quits. My thinking 100 is likely from the time I spent flying C150's.

Is there any reference information on line for calculating accelerated stall speeds and G's pulled, stuff like that? Would be interesting. I'll look.

Darryl

[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?

[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.

[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.

[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

[Marv]

Re: V-Speeds

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

[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

[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.

[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.

[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.

[Guest]

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

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