Gyro assist

[Phill Tadman]

Hi all,

I’ve got some of the new Jeti REX Assist receivers that have 3 axis gyros (rate sensing I think) and various modes for helping to stabilise models. I’m now wondering when and on what axes, stabilisation would be appropriate.

For instance for an aerotow takeoff, I think only roll stabilisation is appropriate - keep the wings level, but don’t correct for yaw (the tug should pull you round) or pitch.

For landing, possibly roll and yaw stabilisation, but definitely not pitch.

Also what to do for a failsafe activation? Perhaps set a gentle turn with rudder to keep the glider from travelling too far, give it full up elevator so as not to exceed VNE and help locate or identify the model, but stabilise roll to keep the wings level.

Any thoughts?

Phill

[spike spencer]

Hi Phill
I'm sure others will comment on the gyro applications during normal controlled flight.
After loss of pilot control and triggering electronic Failsafe functions, if it is just Rate stabilisation and the machine remains above the accelerated Vstall, full up Elevator plus some Rudder could easily end up with a high 'g' descending spiral that goes beyond Vmax at ROD(ridiculous). The Roll [Rate] gyro is unlikely to find the true horizontal.
Alternatively, full up Elev with some Rudder sounds more like a recipe for a well established spin ! If Elevator remains fully up, opposite Aileron and anti-spin Rudder (induced by the gyros ?) may not always lead to recovery and, in some cases, can make things worse.

All that is hypothetical until you actually try the chosen settings to your model. Have fun !

Remember the original purpose of "Failsafe" is one required by the CAA to prevent uncontrolled flight into manned Airspace. Saving the model, or re-locating it after losing sight , is a by-product.

[RobbieB]

................................. Saving the model, or re-locating it after losing sight , is a by-product.

...........and almost certainly, not achievable

[Barry_Cole]

................................. Saving the model, or re-locating it after losing sight , is a by-product.

...........and almost certainly, not achievable

Becoming more achievable than you might think........

BC.

[John Mcnamara]

The main aim of a gyro in the case of a glider is to deal with gusts and turbulence.
My experience is quite limited. Since I sell said Jeti equipment, I thought it incumbent on me to gain experience in the product and I installed an Assist Receiver in an electric powered byplane as a test vehicle.
I found the procedure straighforward enough, and I started with Jeti's default gain and control control authority. On my first flights I had the the gyro switched off and simply ensured that the model was in perfect trim. (do not neglect to do this step!)
Then I switched on the gyro in "stability " mode. It quickly showed what it could do, because on subsequent flights I increased the gain for this model to around 50%, and control authority to 100%. (actually I can see no circumstances where it would be desirable to have control authority less than 100%).
As the day wore on the wind increased to a level were normally I would have ceased flying this model, as it is very lightly loaded. The results were amazing. A fly past at head height required vitually no input from me despite the windy and turbulent conditions. The model was being buffetted, but the gyro not only prvented deviation it kept the model on track.
It is early days yet.
How do I see this technology appying to scale sailplanes? Well in two ways. Firstly, since we are flying scale gliders, I think I can assume that scale realism in flight is something of a priority. Well in turbulent conditions this tecnology will smooth out the flight in a way that the Human hand cannot get close to.
Secondly, in turbulent conditions, as often found whilst slope soaring or approaching over a boundary hedge, I anticipate a much safer approach to landing. Some of my models, the ASH 25 being one of them, are nortoriously diificult to make a safe approach with in turbulent conditions.
If I can achieve these two aims, then the gyro technology will have done its job IMO.
John

[FrankS]

Been using a couple of Multiplex Wingstabi units for around 9 months now, 1 in a foamie (test mule) and another in a powered aerobatic model. Very customizable, so it would be possible to have it roll stabilizing only in one mode and the different stabilization on all axes in other modes.

Not tried it in glider, yet! (but they can do aileron/flap, camber and crow mixes with upto 3 control surfaces per wing), but I would think for failsafe one option would be brakes out, rudder over and hold the wings level, that way model would descend in a flat circle.

Another option would be look at some of the GPS enabled flight controllers, which could do return to home, but the ones I've played with are a bit limited on the fixed wing options, no aileron/flap mix, camber flap or crow braking options.

[John Mcnamara]

Hi Mark,
Yes I really see a Gyro as a landing aid on scale gliders more than anything else. As you say not really needed on the tow.

Hi Frank,
I have a couple of MPX Wingstabi Rx's.
It seems very comprehensive, but takes a lot of setting it up and it needs to be connected to a PC to do this. This is a big negative compaerd to the Jeti product which you can set up from your TX. I believe that there is a blue tooth module for it which will allow connection to an Android Phone. I also understand that MPX have an app that can be run in Android so this may be the way forward.
The Wingstabi did look very complex and I think the learning curve is quite steep, However, I am sure that they will work well with a little application from me.
Yes you are right about Wingstabi being very capable for large gliders as is the Jeti product. Most others on the market have far to few stabilised outputs for modern gliders. Return to home for fixed wing is a big ask.
John

[Barry_Cole]

Frsky have one 8 Ch unit for £ 32.00. and can be setup from a Taranis.. Simples. and Cheaples...



BC

[Roger Stacey]

You may be interested in the March 2018 issue of RCME (due in the shops in a few days) which has two articles relating to this subject.

The first is Part 1 of a series about building a 'Smart' electric powered Flying Wing (Zagi type) using a iNav Flight Controller with a GPS Module.
This will give Launch Assist, Stabilisation, Self Righting, GPS Hold/Return to Home and extra Failsafes.

The second is a test of a 51 inch span foamy trainer (Carbon Cub S+) which using Spektrum equipment does the same as the above plus Virtual Fence (max distance model allowed to fly from take off point) and Autoland (return to take off point fly a circuit and land!).

Simon Cocker also has an article with a write up and photo of the GS at the Nats,

Roger