Vne in a 172

[UnAnswerd]

According to the airspeed indicator, Vne in a Cessna 172R occurs at around 163kts. My question is whether or not the aircraft has the capability of reaching and sustaining Vne, in straight and level flight. (We all know is can reach it while descending).

 

[EagleRJ]

Wind has no effect on airspeed. What are ya- Riddle student?

The 172 cannot achieve Vne in straight and level flight. Full throttle is probably about 120 kts, depending on the plane, and the 65% or 75% power setting you use for flight planning will give you 105 or 110 or whatever the book tells you. Pilots hardly ever cruise at full thottle, since it's hard on the engine and in most airplanes, the mixture increases slightly so you're using much more fuel than the book says.

The only way you can reach Vne is by diving at full throttle (or diving even steeper at idle throttle). Sometime when you're up with your instructor, give it a try! You'll find that wind noise is very loud, and the controls are very touchy, since there is a lot of air going over them making them more responsive. Not a very fun place to be.

Some aircraft can reach their maximum allowable airspeed in level flight, but few GA aircraft can. One exception I can think of is the Tradewind Turbines Bonanza. That's a regular Bonanza with an Allison turboprop out front!

 

[RRF985]

Yeah there is no way. Full throttle in a 172S yeilds around 100 knots indicated. The only way to reach Vne is with a rapid decent.

 

[PropsForward]

Yeah, not going to need to worry too much about Vne in cruise flight. But be aware of it in descents and maneuvering. I fly a C210, and at when ATC asks for more than a 500fpm descent, you have to pull back on the power to keep from going over Vne. Another important area that gets overlooked a lot is Vno, You do not want to be in this range on a bumpy summer day either; smooth air only!

 

[Lrjtcaptain]

I used to fly a 210 many years ago, and never had an issue with 500+ fpm descents reaching VNE, never even got close and I usually left quite a bit of power in.

The Baron on the other hand wanted to do that quite frequently. Anywhere out of 14000ft and descents of around 800fpm with moderate power setting and that thing would get moving quick.

KEEP IN MIND, VNE IS NOT A LIMITATION, ITS A GOAL!!!!!!

 

[Dr Pokenhiemer]

I flew a 210 for a couple of years. I would descend on the localizer from 10,000 feet and about 10 miles out at about 10kts below Vne. I would do this to keep the airliner behind me from having to slow and to keep me from being vectored to follow the guy behind me. Of course, this was late at night (cargo) and you have to do SOMETHING to stay awake! My rate of descent would be 1300-1500 fpm with close to full power. Those were the days--all that excitement for $10/hour!

 

[Bluto]

That's right. Winds have absolutely nothing to do with airspeed. Think of it kind of like a boat on a river, it doesn't matter how fast the water is flowing, airspeed is only a function of movement through the air.

 

[KeroseneSnorter]

So if you're ground speed is ridiculously fast, it won't stress the aircraft as long as the indicated stays below vne?

Gk,

Your profile shows you as a Private Pilot.

If the question you asked above is genuine and not flame bait, please do a couple things for me.

#1. Jump in your car and go to your Flight Instructors home and ring the door bell.....When he/she answers, promply slap the taste out of his/her mouth for giving you such lacking instruction.

#2. Go find a GOOD instructor and start to fill in what the first bozo left out!!!

If you were pulling our chains........Good one

 

[BD King]

Not without a 700 knot tailwind.

HuH??

 

[PropsForward]

I used to fly a 210 many years ago, and never had an issue with 500+ fpm descents reaching VNE, never even got close and I usually left quite a bit of power in.

Yeah, my bad, it is more like 1000+ fpm gets you to your goal...

KEEP IN MIND, VNE IS NOT A LIMITATION, ITS A GOAL

BTW. I like this sooo much that I may have to steal it and use it elsewhere

 

[KeroseneSnorter]

Don't worry about it, I already cut my temp in half and mailed it back to the FAA.

I know it's a trivial thing, don't know why it confused me.

And just because it confused me, doens't mean he left it out. If you asked me if indicated airspeed was unrelated to wind, I woulda said yes. I just had to think about the aircraft moving within the wind to un**CENSORED****CENSORED****CENSORED****CENSORED** my head for that post...like the boat/current...

What really would have baked your noggin would be if I asked how tire speed at touchdown can increase from airport to airport with zero wind and a constant IAS?

Don't worry about it!
Have a cookie, and soon you'll be feeling right as rain

A Career in Aviation!!?? Man oh Man.....why didn't I choose the BLUE Pill?

 

[Lead Sled]

Can a 172 exceed Vne in level flight? Of course not, but take an airplane like a Cessna 206 or an A36 Bonanza, remove the piston engine, hang one of those Allison turboprop STC'd engines on the nose and hang on. Those baby's will run right up to redline. It's just a matter of power.

'Sled

 

[IP076]

Thanks for not crucifying me for my stupidity.

Tire speed? I dunna...rotation of the earth? Coriolis effect? Space time continuum?

Change in Density altitude and the corresponding change in TAS for a given IAS will result in a high GS on touchdown which would result in the tires having a higher rotational velocity on touchdown....

Everyone knows the four levels of learning right? Sometimes Rote just doesn't cut it!

Maybe you should have stayed in those Riddle flight courses!

 

[rumpletumbler]

The imbecile that gave me my private pilot checkride handed me the a/c (172), about 5 knots past redline, about 30 degrees nose down, full throttle, friction lock was so tight it took both hands to release it.

 

[KeroseneSnorter]

Change in Density altitude and the corresponding change in TAS for a given IAS will result in a high GS on touchdown which would result in the tires having a higher rotational velocity on touchdown....

Ahhh, We have a winner!! My faith in the Flight instruction system is restored.

Back in my CFI days we used to take our students to an airport in the mountians that was 3000 MSL higher than our home field. Their first landing up there would give them a vivid example of the above effect. Easy to do in Arizona where it is only a quick flight to find high terrain, a little harder back east.

That one simple exercise always seemed to help the students, even when you got into high altitude and high speed aerodynamics during their commercial program. Unfortunatly every year at higher altitude airports you see a couple guys that were never taught this. They ended up thinking the A/S was wrong because they were moving too fast across the ground and ended up stalling at 20 feet and pranging an airplane. Or trying to rotate too early and mushing back in an aeronautical display!!

What disturbs me is the current trend I have seen torward some RJ types (A certian airline in particular) that are flying around the 121 system not having received instruction, and not having a clue about swept wing aerodynamic properties. Had a guy asking why he didn't get to do full stalls in T tailed swept wing transport catagory aircraft during training? They all know they have a shaker and a pusher, but none seem to have a clue as to why the manufacturer installed them. I have wondered if the lack of knowledge of high altitude and swept wing aerodynamics had a factor in the RJ double flame out at 41k and the resulting crash? Getting too far into the coffin corner at FL410 would be a plausible explanation for the events.

Of course I am only speculating here, I know nothing of Pinnacles training, never having worked there, and I am not judging, just wondering.

 

[EagleRJ]

Getting too far into the coffin corner at FL410 would be a plausible explanation for the events.

KeroseneSnorter-

Speaking of flight instruction...
You may want to do some reviewing yourself. "Getting too far into the coffin corner" is improbable for the CL-65, and even more so at the accident flight's light weight. I'm also scratching my head as to how high-speed or low-speed buffet would cause the engines to flame out?

BTW, the Monday-morning quarterbacking on this flight is being done here.

 

[KeroseneSnorter]

KeroseneSnorter-

Speaking of flight instruction...
You may want to do some reviewing yourself. "Getting too far into the coffin corner" is improbable for the CL-65, and even more so at the accident flight's light weight. I'm also scratching my head as to how high-speed or low-speed buffet would cause the engines to flame out?

BTW, the Monday-morning quarterbacking on this flight is being done here.

Improbable if flown correctly. Flame out could have occured due to a lowspeed(unlikely given the shaker, pusher) or accelerated stall situation(More likely, The FDR will tell the tale). I doubt that an RJ does anybetter in a full stall than any other T tail swept wing A/C. Given that the crew of the 65 had probably never been to 410 before in it since it is normally too heavy to make it and that a Double flame out WITH associated internal engine heat damage and the inability to get a relight is well....unusual to say the least. Fuel problems? Possible, but seems unlikely since it got to 410 to start with. Most fuel problems show up much earlier than 30 mins or so into the flight. Fuel temp problems may be it.

Who knows. The NTSB will inform eventually.