engine out and h-v avoid areas

[WaspAir]

Several threads recently have had discussion of low-level engine failures, which always gets me thinking about height-velocity issues.

Please respond by identifying what kind of gyro you fly, and providing some numbers to describe your own h-v region of concern (combinations of height and airspeed from which a safe landing is challenging to impossible if the engine fails).

I've attached some admittedly poor copies of h-v diagrams for an A&S 18A and McCulloch Super J-2 that I happened to have handy as I typed this, to help describe what I'm asking.

What I'd like to know is where the "corners" are for you in your normal operations, such as:

*height at the top/zero airspeed (e.g., 300 feet for 18A, 400 for J-2)

*position of the lower right corner (e.g., 45mph at 25ft for the 18A, 46mph at 15ft for the J-2), etc.

[WaspAir]

Well, I started this thread 24 hours ago, 84 people have looked so far, and nobody has responded with any information. If I'd posted a picture of a kitten I'd have gotten more response.

I'm actually interested in safety and performance of the wide variety of gyros in use.

I'd really like to know, folks - "pretty please"?

Here's a kitten just in case.

[StanFoster]

Waspair- Cute kitten....ha. :yo:

The R22 I am flying starts ay 0 airspeed at 400 foot...then slopes down to 50 knots at 200 ft....then you can fly down to 100 ft. at 50 knots, where it then curves back to 10 ft at around 30 knots down to 0 knots.

I dont know what the numbers are for my Helicycle, but the information will be supplied before I start flying it.

Stan

[fiveboy]

Please respond by identifying what kind of gyro you fly, and providing some numbers to describe your own h-v region of concern (combinations of height and airspeed from which a safe landing is challenging to impossible if the engine fails).

I can answer what I fly and what my min AS is but the way this is posed makes me feel like its akin to when did you stop beating your wife?

Not being a smart a$$ but isnt the min height and AS whatever you can bring off? I mean if the engine fails just at lift off you should be able to land safely. If you are 2000 feet up with plenty of AS to the ground you can still botch it.... so what are these numbers these absolutes these theoreticals... and moreover what do they prove?

(Also how do you figure them out without balling up!??)

[StanFoster]

Fiveboy- If the engine fails right after liftoff...you are in the correct portionn of the HV diagram.

I had a Bensen years ago, and I used to do vertical descents down to no less than 200 ft. One day right when I was descending vertically and was right at my 200 ft. minimum, I added power but the engine died. I immediately nosed her down and remember thinking airspeed..airspeed...I remember getting it to 45 mph, flared and just landed with a little thump. I would say that for me..I was in the grey area of the HV chart. After that...I moved my minimum altitude at 0 mph to 250 ft. for a little extra margin.


Stan

[WaspAir]

Fiveboy -
Sure, you could blow it from 2000 feet. That's not the point. It's a question of what combinations of airspeed and height will give you adequate energy to make a safe landing without divine intervention and/or having to be Chuck Yeager, Wilbur Wright, Bob Hoover, Sean Tucker, Igor Sikorsky, and Charles Lindbergh all rolled into one.

For many light rotorcraft, if the engine chooses to retire at 0 kts and 40 feet, no matter who is flying there will probably be wreckage on the ground. Keep going up, and eventually you'll reach a height from which you can establish some airspeed to use for a descent-arresting flare, and land without damage. The h-v diagrams I posted for the 18A and J-2 show those as 300 and 400 feet. I'm asking what you think the corresponding numbers are for your Sparrowhawk, Dominator, Bensen, or whatever type it is you fly, and whatever other numbers you use, such as the other corners I mentioned.

The numbers don't prove anything, but they're an important guide for pilots to keep them from bending their aircraft. There's also really nothing "theoretical" about them if you use them in your daily operations to stay out of trouble.

You might not have a precise diagram worked out for yours, but if you're flying it without an idea of what those numbers are, you may be taking some serious and unnecessary risks.

[WaspAir]

I had a Bensen years ago, and I used to do vertical descents down to no less than 200 ft. One day right when I was descending vertically and was right at my 200 ft. minimum, I added power but the engine died. I immediately nosed her down and remember thinking airspeed..airspeed...I remember getting it to 45 mph, flared and just landed with a little thump. I would say that for me..I was in the grey area of the HV chart. After that...I moved my minimum altitude at 0 mph to 250 ft. for a little extra margin.

Thanks, Stan - that's the kind of information I was hoping to get.

[Oskar]

Some people take their gyro down to zero airspeed, my gyro (a gyrobee with MZ202 engine and 24ft Sportcopter blades) starts giving me warning signs when the AS drops below 25mph. I will go down to 20mph but have no intention of ever finding out what happens at zero AS.

From 20mph I need about 100ft to land comfortably. Air speed at the start of the flair needs to be 30mph, any slower and the landing is bound to be less than soft.

[Fl90]

I thought about it when you posted. The variety of characteristics of a single machine with different rotors started through my head, then I started thinking of other machines. It got more complicated, quickly.

The rotor type seems more important to me than the machine. When I'm new to a machine or rotor, I keep the speed above 45mph(40kts), untill I've had time to run through a power off glide and a few banks and flares to see how responsive the rotor is to loading and speed.

My experience with the Bensen blades mirrors Stan's.

Phil

[birdy]

The numbers don't prove anything, but they're an important guide for pilots to keep them from bending their aircraft.
Yup.
IOW, do you know wot the min hight is for you and your machine for the currant situation, if the noise stoped?

And to be realistic, theres alot more to consider than H and V.
As Phil states, machine, rotor, and weight combinations.
Can you approch streight and land shallow, or dose it have to be a low AS steep decent onto a spot, is it ahead, to one side, or behind you...............?
Wots the air do'n??
If your not sure, go higher, simple.

[fiveboy]

Fiveboy...

...You might not have a precise diagram worked out for yours, but if you're flying it without an idea of what those numbers are, you may be taking some serious and unnecessary risks.

Not being a smarta$$ honest... No fight here just asking real questions.

Ok. I never fly below 40mph AS. I know I can land from any height if I have that.

In order to test whether I can go below that, should I go up to say 1000ft, get to 0 AS and then nose down hard until I reach 40AS and clock how much alt I used up?

As Birdy indicated, wouldnt the wind conditions, attitude of the gyro etc make these into goal posts that are moving? How is this an absolute and not a theoretical.

Shouldnt this be something we know from flying our machine, VS a chart?

For me in my Tandem AC the listed min AS is 20 mph.... I dont believe that for a second. Its 40. I figure as long as I have that regardless of my height, I will land (assuming my rotors are turning at least 300 rpm- 320 if I have a passenger).

When I see anything at the edge of 40 I nose her down and pick up AS.

[helipaddy]

On my Dominator, I need 40 mph at the end of the glide to make the flare comfortable. any less and its a bit of work and timing to get it right. I think 0 airspeed and around 200 ft would be the limit in order to get 40 mph comfortably for the flare. best rate of climb on my machine appears to be 47mph .
So I think its around 3ft to 40mph then 10ft to 55mph then up to 50 ft then back to 0 mph and 200 ft. And using a standard climb out speed of 50-55mph.

I would like to know what experienced Dominator fliers think

Paddy

[WaspAir]

As Birdy indicated, wouldnt the wind conditions, attitude of the gyro etc make these into goal posts that are moving? How is this an absolute and not a theoretical.


The actual altitude at which you fly must, of course, include consideration of all the current conditions, but you have to have a starting point somewhere from which to make adjustments for those conditions. It's that starting point that I'm asking about. Just as performance charts in all aircraft manuals assume certain conditions, h-v numbers must, too.

Let me propose that we assume you're right over a really big friendly airport with no tower or traffic, there's no wind or turbulence, the airport's at sea level with standard temperature and pressure, and you're at your normal weight with full fuel tanks.

If anyone has seen the need for a significant variation on their numbers when using a different make or size rotor blades, that would be interesting for others to know, too.

[WaspAir]

Ok. I never fly below 40mph AS. I know I can land from any height if I have that.

In order to test whether I can go below that, should I go up to say 1000ft, get to 0 AS and then nose down hard until I reach 40AS and clock how much alt I used up?

...

For me in my Tandem AC the listed min AS is 20 mph.... I dont believe that for a second. Its 40.

I would never suggest that you do anything that violates a limitation for your particular aircraft. Getting very slow, however, is something many pilots do, whether intentionally or if distracted. Low airspeed high sink rate descents are also fairly popular (and there's even a task in the Private Pilot practical test standards for entering, recognizing, and recovering from high rate descents, with a floor of 500 feet). It seems sensible to me that if people are going to fly low, slow, or both, some discussion of what margins are used could be worthwhile.