Flapping warning device

[anthom]

Having flown different tandems, side by sides and a single, I find some of the commonalities in all gyros that I've flown that are not jump take off capable as:

1. All of them need pre-rotation to get the blades spinning. Whether it be by hand or a mechanical one, the fact is clear that all of them need to be brought up to flight RPM. Part of this is done when the gyro is stationary, and part of it is when the gyro is rolling on T/O. The small differences would be in the specific POH. This again would be different for different types of rotor blades. However, all of them start the pre rotation with the disc tilted forward and then tilted back as the roll commences and begins to speed them up more. This is by a combo of throttle and disc back.
In my own personal experience, I had a single Dominator with an electric prerotator that would not come up to speed, and if I tried nursing the Dragon Wings up to speed, I would often experience the onset of blade flap and I would abort by pushing the cyclic forward and cut throttle. The DW blades were replaced by McCutcheons and the problem went away.

2. Regarding the landings, coming in at forward speed is not the issue, but what happens prior to touch down. As pointed out by WaspAir, the physics is clear. Mass x velocity = Momentum. Mass is pretty much fixed. So obviously the only control is of the velocity. I do not see how any gyro can tip over at touch down when the velocity is zero. Yet they happen, and that is usually attributable to a vertical descent prior to touch down, or the disc flapping due to sudden wind gusts. The severity of the impact will be greater where the impact is associate with forward speed.
From personal experience again, I was coming in for a landing in my tandem and unknown to me, the nose wheel had come loose at the spindle shaft due to a design anomaly; and I landed as usual on the mains and after the nose wheel touched the ground, it immediately acted as a brake. I would have had a different outcome if I had landed with forward speed. I prefer to use the rotors as a brake right after T/D.

While the nitty gritty of the above two issues can be flogged beyond death, the fact is clear that the focus on the training ought to be on teaching students to manage the rotors in all situations with proper rotor management, and to manage take offs and landings that avoid the causes leading to the possibility of mishaps.

As an aside, I have seen what some students that have trained with other instructors prior to coming to me do. I see that some have been taught in ways that do not conform to the simple stuff that I have explained in my above post. This is truly disconcerting.

Just my thoughts.

 

[Mike G]

Resasi

“Petulant” maybe but I’m getting old and more and more tired so it’s difficult not to become a cantankerous old man.

“you appear to be throwing your toys out of the pram”

I think you’ve got it the wrong way around.

The way I see it is that I was offering the community a new toy to play with (discuss). But the community decided it didn’t want to play with anything new it wanted to play, yet again, the same tired old game of arguing about the same tired old solutions that will never happen like an ideal training system that would have a perfect syllabus for perfect instructors and perfect students or design changes that no manufacturer will make.

So I “got over it” and put my toy back in my pram.

Back to the new subject of this thread

“Training and design changes to reduce blade flap (sailing) on take-off”

Abid and Vance give us 5 examples in posts 44, 46 & 59 of pilots who were apparently all trained by well recognized, competent instructors and who were signed off for solo because (among other criteria) they had managed to make numerous successful take offs avoiding blade flap. From post 59 these guys had probably all had flapping demonstrated and perhaps they’d even done some balancing on the mains.

This leads to the conclusion that I think Abid was trying to make in post 44; perhaps the problem isn’t training after all.


One day these 5 qualified gyro pilots allowed themselves to be distracted or stressed to the point that their actions got out of sequence and the muscle memory of gyro training didn’t kick in (or even worse their FW muscle memory did). At this point, where they had clearly lost the plot, no amount of balancing on the mains or free castoring nose wheels would help them (I do agree with those that argue that the Magni type flexible drive offers a less "bunched" procedure and could help).

I believe that at this critical point if they heard a voice that they were used to obeying (their instructor’s or maybe even their wife’s) in their headset saying “hey buddy if you don’t chop the throttle you’re going to have a very expensive blade flap and crash” (obviously this is humour please don’t comment that it’s too long) then all/some of these 5 accidents would/could have been avoided. Not all of course, we all know of guys who have landed with their wheels up while the alarm was screaming at them from finals to the crash site so some will ignore the warning and crash anyway. We simply have to accept that there will always be some crashes but if we can reduce the numbers it has to be good for the gyro reputation.

But you don’t want to talk about my new toy so I’ll keep it in my pram.

Mike G

 

[Resasi]

Well glad your still posting Mike, and know what you mean about getting old and less tolerant. Old does get more difficult as we explore it further.

I certainly acknowledged the value of a device along the lines of your proposal in my previous post No 60, as I feel the cost of such an item that would at the very least save the cost of a trashed set of blades, must be worth it.

Your ‘toy’ certainly remains very relevant so please don’t take it back, and just acknowledge that these threads do sometimes meander and drift while remaining round a core subject.

probably all had flapping demonstrated and perhaps they’d even done some balancing on the mains.

That is a point where I would say that the five last gyro PPL’s who I assisted in transitioning from two seat to single seat were deficient.

To demonstrate blade sail/flap in a single in very simple, on a windy day, perhaps not suitable for the single seat student to venture out, and Murphy makes sure that happens all the time; with the single seat chocked, engine off, facing into wind and student in the seat and briefed, stick forward disc horizontal, the instructor pats up the blades. Then the student uses the stick to gradually increase the disc angle of attack and spin the rotors up. If he does it too aggressively/quickly and hey presto the lesson begins. Not quite so simple on the two seat though, I did get this demonstration in an RAF 200 from my instructor.

I would also say that here in the UK very little balancing on the mains was done by the five last guys my Instructor and I have transitioned to the single seat gyros. All had gone through the Gyro Experience training and one was a Gyro Experience Instructor. With the superior longitudinal stability of the two seaters PIO and overcontrol is far less evident and therefor balancing far less of an issue and not a lot done on it. The thing is that with the extra wheel balancing generally done on a single, there is more rotor control necessary even if it is not called that.

Point is that even a very experienced gyro test pilot for the CAA/LAA here who was demoing/testing/experimenting with it in a two seat machine unfortunately had a whoopsie. So not as easily demonstrated or practiced in a two seater with the much longer, heavier, more expensive rotors and of course machine, to be careful with.

Any instrument or training that prevents a leading cause of gyro accidents from occurring can only be a good thing for the sport, so be a good sport and get your toy out of your pram.

 

[Alan_Cheatham]

Stall warning devices are so common on fixed wing aircraft as to become standard, I can't understand why any pilot would object to something similar for gyroplanes if the details can be worked out.

Just from casual observation it seems that more rotor management accidents occur to gyros with fully enclosed cockpits, perhaps being enclosed isolates the pilot enough from the rotor as to become a distraction, more cockpit orientated rather than full aircraft orientated. It would be interesting to examine data and see if this is statistically true.

 

[EI-GYRO]

Fixed-wing gliders use a varying tone device to indicate rate of climb/descent which seems to work well, and the pilot actively listens to it for info.
Perhaps something along those lines might be helpful, but not using up scan time or distracting the pilot. A rising tone could indicate the approaching safe limits.

 

[Mike G]

Following my cantankerous old man’s diatribe against the gyro community in general I owe an apology to those who did actually try to contribute to my thread.

To those who proposed some sort of flashing light or visual system of warning I would say that any such warning would require the pilot to:

• Look at the visual warning (when perhaps he should be looking outside the cockpit).
• Then interpret from the colour or rate flashing or whatever which alarm is going off (remember this device is planned to have 4 separate alarms, flapping, behind the curve, bunting and overspeed).
• Then remember which corrective action is applicable and apply it.

Since in some of these cases (flapping on take off for example) he’s already out of sequence and has lost the plot it’s highly unlikely he’ll make the correct action in time. Flapping and bunting are very rapid events.

EI Gyro’s idea of using the glider varying tone rate of climb type audible warning system would suffer from the same problem of interpretation of which error and correction was applicable and is a much more intrusive device in that the pilot using it could be tempted to use it as a clue as to when to make an action such as pulling back on the stick. The device I am working on is designed to be passive as long as the pilot is flying within limits this device says nothing, except as he flares to land he’ll get a message as he passes behind the curve but that’s just like the stall warning on an aircraft that beeps as you touch down.

As I said in another post the hardware and software are currently being tested and I'm waiting for a new Mk 2 hardware and software package, so we are unlikely to change unless it simply doesn’t work. Thanks anyway for the ideas.

For those that still maintain that training is the answer, this device is planned to have (still working on it) a training element in it. It is planned that the instructor will be able to set off an alarm of his choice to help train the student to react correctly to each of the audible warnings. Of course there will always be pilots who still screw it up but if it can save some of the accidents it’s got to be worth doing.

Mike G

 

[Mike G]

One of the features in the new hardware is an altitude compensation for the calculations.
Those of you who fly from Hot and High airfields, what is the altitude of your field and what sort of temperature range are you seeing? We have to decide if we need a temperature compensation as well.
Mike G

 

[Mike G]

A question of vocabulary.

The attached pdf is a typical Power required/power available curve.

What do you call the points A and B?

What do you call the zone between A and B?

What do you call the zone to the left of B?

Thanks
Mike G

 

[XXavier]

A question of vocabulary.

The attached pdf is a typical Power required/power available curve.

What do you call the points A and B?

What do you call the zone between A and B?

What do you call the zone to the left of B?

Thanks
Mike G

A marks the point of minimum power required (maximum endurance), B marks the point of the minimum airspeed at which s/l flight is possible, and the region between A and B is known by some (but not by all..) as the 'region of inverted commands' or the 'backside of the power curve'...

To the left of B, level flight is no longer possible. The power available is lower than the power required...

BTW, not long ago, I sent a question on the zone between A and B to 'Aviation Stackexchange': https://aviation.stackexchange.com/...-is-the-zone-of-reversed-commands/70416#70416

 

[Resasi]

Concur with XXavier.

Good points about audible warnings and tones, voice I think best.

 

[WaspAir]

...and the region between A and B is known by some (but not by all..) as the 'region of inverted commands' or the 'backside of the power curve'...

In American usage, the usual term is "region of reversed command ". Reversed because it takes more power to go slower, which is backwards (en arrière) from normal expectations. Inverted is used to mean upside down (à l'envers). Hope my French makes sense; don't know any Spanish. (Rückwärts oder verkehrt herum?)