Reely340

The normal pitch blade angel should be adjusted just as it is nowadays.
That "ultra low" section of the pitch level travel would require considerable force to overcome the "protective spring" to get into and hold there.

Hence w/o actually postitively and deliberately wanting to go there one would
never reach that range. It should be an eyes popping out, "we're all gonna die" emergency option only.

Nevertheless pitch angle adjustment precision during maintennance would be more intricate, that's for sure.

chopjock

I made a similar observation / asked a similar question in post 267.

Reely340

You did exactly what I meant! That spring loaded protection I was taking about should make sure one doesn't accidentally reach "negative blade angle" region of pitch lever travel during normals ops. So while your drone pitch stick probably has the travel evenly divided between say -12° and +12° blade angel, I'd like to have a very assymertic setup, that - unless applying great force - will behave exactly as the pitch levers do nowadays.

So, any idea why we are denied that vital last resort feature by the manufacturers?

AnFI

Quote:

Originally Posted by [email protected]

AnFI, I don't seem to be able to find the hp gauge in the cockpit so is my VSI calibrated in hp, brake hp or shaft hp?

Of course you know that hp is derived from torque at various rpm so you will need to know the exact rpm of the engine at any moment to calculate the hp - that's a lot of extra stuff to think about when you are flying but I know how brilliant you are

For those not stuck in the Dark ages - one hp equals 0.76 Kw (that is a kilowatt an FI, the watt being the SI term for power) Or shall we just use the torque gauge that the nice man who made the helicopter gave us? (yes I know not every helicopter has a Tq meter but which RFM has limits based on hp????)

RotorIP - don't worry, he has got lots of stuff like this that he believes everyone should teach

Sorry Crab only just saw your (strangely rude, brash, sarcastic and unpleasant, why?) ref to my post.
I think you did possibly miss my point.
YES your VSI is effectively a Power Meter... where ROC or ROD are effectively measures of the Energy/Time (Power) either required from Fuel (most likely) to give you Height(energy)/time or the Energy rate (Power) contributed from Height (Loss) rate and so not required from Fuel (or Speed or RRPM).
So it just gives a handy picture of wtf is going on when you waggle your sticks around, in case you were interested. So a Torque meter doesn't do that for you.
The Hp is interesting because it fits elegantly with the units we use. You don't need a calculator to work out you need to put the lever down, but a little general understanding of the scale and value of the energy resource you have and the rate you use it under different circumstances isn't actually going to do you much harm, it might even help?
Each 330lbs your aircraft weighs is worth a Hp per unit on the VSI. - hardly rocket science. You probably know the Hp required for cruise, at least?
Brake or shaft doh! haha neither its 'ball park' Hp (conversion efficiencies etc).
("ball or aersol" neither it's for my armpits)
( A Hp is 330lbs at 100fpm, of course you can do it all in SI if you want its just not as pretty and you will need a calculator
and yes I think at the least crusty old sea dogs like you should understand some of this stuff, maybe even enjoy, but... scoff if you like. )

I'd probably listen respectfully if you wanted to tell me how to land in brown out on NVGs on one eye and landing light with the other eye, in 80kts wind, on a pitching deck 400miles out etc etc ooops wtf can't u be slightly respectful?
Time of month again? BTW have you been pulled into this Civvy SAR thing yet?

.... and RotorIP you seem to have been corrected by Jim Eli I see (thank you) re 1sec/2sec.

Lonewolf_50

Huh?
AnFI, your VSI does not care if your are at full max gross weight or sucking fumes with no payload at min operating weight, or anywhere in between. At low gross weights you will get a different amount of power needed to successfully get a given climb, level, or descending performance.

The VSI measaures your rate of change of pressure altitude.

Granted, your power/pitch settings will result in a performance readable in rate of descent, but POWER has to account for weight versus performance desired.
So, NO, I don't think you are making a decent case for the VSI as a Power Meter.

It is, however, a performance instrument, which can indicate whether or not you have your power set for the performance desired. Perfect example is a constant airspeed descent, in instrument conditions. If you are not descending fast enough your VSI is a cue to adjust power (reduce), and if you are descending to rapidly, your VSI is a cue to adjusting power (increase) ... but the power meter is your torque gage.

Depending on your GW, the DA, air temp, and other environmental factors, how much torque or power you need to get a given performance will vary.

AnFI

Don't see how you can say that it's not a good case when you appear to have missed the point about the weight.

I am clearly accounting for the weight - that is the point!!

Yes the Weight mulitplied by Vertical Speed is Power!!


the rest is fairly irrelevant (but pretty) about units:


Each 330lbs your aircraft weighs means 1Hp for 1 unit on the VSI.

or (in other words)

AUW/330lbs times VS (in 100fpm) is power.

or

Divide your weight in lbs by 330 and what you get is how many Hp each 1 unit on the VSI is worth.


It is effectively your Potential Energy Power required/gained.

As opposed to your Fuel Energy Derived Power (which is what your engine is does and you'll find information about that on a Torque Guage etc).

Please confirm that you were missing the point or have I misunderstood your point?

If you don't understand that or don't think it's pretty then f.. f... f... fine

Lonewolf_50

AnFI, I too went to college, majored into Engineering, and learned how to break things down by units so that units in solution are the same as units in the problem statement.

What you are doing is playing games with semantics. "Power" in a cockpit during powered flight is part of the "pitch and power equals performance" equation.

I understand the game you are playing, and am trying to point out to you that when flying, the semantic game isn't one worth playing. Power in powered flight has a particular meaning and nuance. Energy management doesn't need the units you are using to be effective: torque, or thrust, percent rated torque, or thrust, altitude, and airspeed are units sufficient to the task when operating in powered flight.

Thanks anyway.

AnFI

it is more than just dimesional analysis. it really is the Power where the energy element is Potential (Height) Energy. It's quite nice to know that 1 unit on the VSI is 10Hp for instance. I like it, others might - but you don't have to like it

Boudreaux Bob

Lonewolf_50

Video, from time 2:35 to 2:41.
As I've been saying, fly with both hands.

JohnDixson

For Reely340:

Articulated rotor heads have both droop and flap stops. Typically, the anti flap stops are single purpose: to prevent excessive flapping with blades at very low Nr or stopped. This function is primarily aimed at gusty wind conditions. The anti flap stops are single setting and designed to get out of the way at a reasonable Nr and cannot be contacted in flight.

Droop stops are another matter. There are two settings: one for ground operations and one for flight operations. Depending on the manufacturer, the geometry of his machine and the rotor characteristics, the ground stops are usually in a range of 0 to-1.5 degrees and the flight stops are somewhere between -4 to -6 degrees. The flight stops are there to prevent getting the blades into the cockpit roof, the engine cowl tops and the tail cone. I just mention this because some of the rigging geometry that you have proposed generates conflict with these other realities.

gator2

I got my PPL 140 hrs ago in a 22, and now flying 44s. Just so you all know, this thread was a real eye opener for me.

As a result, I hired an instructor and spent 4 hrs flight time over the last couple weeks with an inst entering autos from all different flight configurations, high speed low speed, hard climbs, etc. My instructors were a little bemused that I would do that, "as more accidents happen practicing than as a result of engine failure".

Don't know if that stat is with instructor or solo.

But, before I did this, I am sure that I would have botched an auto entry if the engine quit at 110kts. Every auto I entered while getting my ticket, and subsequent flight reviews was around 75kts. HUGE difference.

Now that I know what a 110 kts entry requires vs a 75 kts, it seems intuitive. Which explains, I guess, why instructors are bemused by a guy who wants to go up and practice stuff that is not required. But, looking at the diff as a rookie, not at all the same.

So, if the engine ever does quit on me, in spite of all pissing going on in this thread, if I make it the thread will have played a big part in my survival.

[email protected]

Good for you gator2 - hopefully you now fully understand what Lonewolf 50 means by There is no 'one size fits all' technique for every situation so the more height/speed/power combinations you have practiced autos from the more likely you are to survive.

Now when you are flying around you can get into the mindset of 'what would I do and where would I go'? if the engine quit and learn to judge which landing areas are within reach of your new skills and which aren't.

Boudreaux Bob

The old saw of "Bad Approach means a Bad Landing" holds in auto's. Get the entry right and everything after that generally will fall into place. Get the Entry Wrong and rarely does it work out for the good.

Helicopter Pilots live and die by Rotor RPM. It is just like Air, too little and bad things happen.

You can arrive at the bottom with too little but rarely can you get there with too much?

Pittsextra

http://www.aaib.gov.uk/cms_resources...I%20Append.pdf

DOUBLE BOGEY

Errrrr, Bob, I think you got your logic wrong in your last sentence!!!

Surely you meant:

"You can arrive at the bottom with too MUCH, but rarely can you get there with too LITTLE"

DB

[email protected]

No, Bob's logic is sound - you can always get to the ground with too little Nr - plenty have managed it - it's just not a pretty sight when it happens.

Arriving at the bottom with too much Nr needs qualifying that the Nr is not so high that the blades depart due to stress on the blade root

Pittsextra - we used to do double speed select pulls on the Wessex during pilot training and the Nr decay was pretty quick! Lowering the lever and flaring worked every time but flaring and not lowering the lever didn't.

rantanplane

Basically, rotor RPM only matters for getting off the ground. Hence heli pilots surely die because of rotor RPM

Boudreaux Bob

A properly rigged and test flown to certify that, aircraft can not achieve such rotor RPM sufficient to "sling blades" during autorotation. Perhaps with some real effort one might overspeed the head but not to the point of a catastrophic failure.

Getting to the bottom of an autorotation with too few Revs....deadly situation.

If you get there with "Too Many"....raise yer f@cking lever a bit and use that excess to your advantage! Or perhaps not do as aggressive a flare and use the excess that way, but that excess is a bonus.

Think not....try the reverse where you don't have enough and see how it turns out.

A for instance is the Glasgow Pub Visit by Plod.

Chairmanofthebored

It seems clear to me that this pilot [Peter] just completed failed to react appropriately to running out of fuel. Forget the auto and all that - it was a case of incompetency. Just because one has flown for a long time, does not mean that in a situation of stress that a mistake can be made. It is completely bizarre that he didn't react to low fuel situation quicker.