Alex48

I'll have a look...anyway, I've just started using a DX18 as I needed the extra channels for all the functions on the A4 so its going to be set up from scratch so I'll know there are no unknown transmitter mixes/rates present. In your experience using the i-gyro with these jets do you find HH worked when adding flap/slat? Al's large T33 was the same when we set the i-gyro up but he hated HH anyway so it all got turned off rather quickly.

siclick33

When using Heading Hold for elevator, what is the gyro trying to 'hold'? Does it hold flight path or pitch angle? If the former then I'd be very interested to know how it does it.

If it holds pitch angle then I'm not sure how good it would be during flap deployment? Dropping flap changes the camber of the wing and increases lift and if the gyro holds pitch angle constant then the model will balloon. Conversely, if pitch angle is held constant when the flaps are retracted, then the model will descend. The pitch attitude needs to be adjusted when flaps are moved for the aircraft to stay level and I'm wondering if the gyro would have all the information to be able to put in the required correction.

BarracudaHockey

My Feedback: (11)

It will keep the pitch angle (or heading) constant until it runs out of throw or airspeed.

Andrew Bailey

IGyro maintained Heading mode for me when I had it in my Classic Flash. I did not like the Heading hold thing either and ended up taking the iGyro out as I realised that I was not enjoying flying Flash as much as I did without it. No question, in a gusty wind you would notice the extra stability, but I did not like the rather artificial feel that it gave to the handling. Something like the Flash just does not need it. I do think that anything large and/or scale would benefit greatly from the iGyro. It's a seriously well thought out system.

Harry, I would certainly consider this as an excellent option for your Lightning.

HarryC

My Feedback: (1)

You and some others are not saying why though. You need to explain why, and in the light of products like the i-Gyro and Eagle tree Guardian using heading hold you need to explain why you are still fundamentally against it.

Alex, would be very interested to hear from you or Ali about why HH was not liked.

Andrew B, would also like to hear what it was that you didn't like about the feel of HH on elevator.

I have been using the Eagle Tree Guardian in prop models, in HH and rate modes. HH mode works well except that whatever you apply on the Guardian works to all 3 axes, and HH on rudder is bad as it makes the model sideslip in every turn. It isn't a fault, it's just that the control logic is optimised for 3D aeros rather than normal flight and HH on rudder would be good for things like Harrier rolls. However HH on the aileron and elevator works very well. Initially I feared that HH on the elevator would lead to unexpected stalls but it doesn’t. The thing is that you need a certain amount of back stick, usually a lot, to provoke a stall. The gain you set is in effect a max travel that the gyro can cause and if that is less than the elevator required to stall, the gyro in HH can’t stall the model because it simply can’t pull the stick back far enough. You only need a little gain to maintain attitude in normal flight speeds, any more and it starts hunting, and that low level of gain just won’t cause a stall.

I tried flight testing a trainer model in HH with a good amount of gain. What happens when you slow down? I put the model into a climb about 30 degrees and throttled to idle. Instead of immediately lowering the nose and maintaining speed, it stayed in that attitude as the gyro applied more and more elevator. Then still with some speed left the gyro reached its max gain/travel and the nose started to come down, until the model was descending still with the up elevator applied by the gyro. So the nose drops before the stall is reached as long as the gyro gain is less than required for the stall. I added power gently and the model just lifted its nose a bit, I added more power and so on and it just kept lifting the nose until it got back to the 30 degree nose up where it started.

I tried the same thing in level flight, throttle to idle, the gyro kept the fuselage level as the model slowed and started losing height, it ended in a level attitude descent at low speed but safely above the stall.

I then flew the model in level flight right to the point of the stall and released the stick. Since the gyro gain could not pull the elevator as much as I could, it promptly reduced elevator! The model nosed down a bit and descended but now well clear of the stall. I slowly applied power and it lifted the nose as I kept slowly applying more power, until it got the model into the same nose high attitude where I had let go of the stick but of course it now had more power and speed and was climbing. As I applied more power it just kept that same nose up attitude but accelerated up the climb.

You can get some unexpected effects when pulling higher angles of attack. For example if the gain means the gyro can pull about ¼ up elevator and you have it in slowish flight where the gyro is applying all of that, you start to pull back on the stick yourself which immediately cancels HH mode but you may have pulled back 1/8 stick, the gyro was applying ¼ stick so though you have pulled back the elevator has reduced not increased and the nose goes down in response to you pulling back a little. I also found that I lost some of the feedback about angles and speeds that pulling back on the stick gives me in slow flight.

For normal flying around I found that HH on elevator worked very well, but that at higher angles of attack/slower speeds it can give some odd effects and remove some of the information the pilot gets from the stick position about how the model is performing.

stevekott

What I think might get you in trouble is in those critical flight phases where the gyro may be holding the nose up. Normally we set the CG of our planes slightly nose heavy so in situations where there is less airspeed (approaching stall) the nose wil drop increasing airspeed. If the CG is too far aft the tail will drop instead of the nose increasing the likelihood of a stall.

The gyro can't sense airspeed, just attitude. So if the airspeed gets low there will be no tendency for the nose to drop so you will need to be much more keen to it. That's one place I've seen guys pancake it in with a gyro.

I put an FY-30 stabilization system on my Skymaster F-18. It showed some promise but occasionally it hit some random vibration (it was very welll insulated) and made the jet react violently. I took it out. I still use a simple rate gyro on the nose-wheel. The thing with jets is everything happens so fast.

It's always fun to play with new stuff just make sure you have a good "OFF SWITCH" option and you know exactly how to hit in a split second.

Art ARRO

My Feedback: (5)

Questions for Jack D. and others on this thread. At the recent Toledo R/C Expo, I purchased an Eagletree Guardian for application in my SMGripen jet. As you may know this jet is a high workload on landings with PIO from the canard. I have tamed this somewhat by reduced throws and CG adjustments but would like to try the Guardian stabilizer also. To Jack with the Rafale; I presume you used the "2nd Elevon Reversed" function to control the canard, true? Also, have you tried the "Derivative Gain" option on the unit for your Rafale? I feel that it would work well especially on the wing elevons for roll stability. Any other recommendations would be most appreciated. Note that I plan to install the Guardian in several sport models before the Gripn to gain familiarity with the unit. Thanks in advance.

Art ARRO

GR7Racer

I had my first experience with the IGyro this month helping Joe Castelao setup his Cougar. It worked pretty much as advertised, but HH on the elevator did not work to keep the aircraft level with flaps deployed. We originally had arrived at 15% up elevator mixed in with flaps to keep the airplane level. Before setting the HH gain, we disabled this additional trim and when flaps were deployed the nose did not hold attitude and dropped. We ended up disabling the HH on elevator and restoring the elevator up trim in the flap system. That was my experience with it.

Now my opinion... I agree that different airplanes are going to need different angles of attack to maintain altitude in different configurations of flap, gear, and airbrake deployment. The HH on elevator can't compensate for all of this unless it also factors in rate of climb/descent as well as airspeed. I don't believe the Igyro does this. On top of that, as soon as you move the stick anywhere off of center, the HH disables and now you are on your own to keep the AoA correct.... well who is disciplined enough to not even breathe on the elevator in order to keep HH active? How do you turn the airplane without adding additional elevator and deactivating HH? Theoretically, the HH would hold the nose up in a turn for you, but in practice it does not. It's possible for certain aircraft types that don't require large trim adjustments with flap deployment to probably get away with using the HH to maintain a rough trim, but it seems to me that it won't be able to compensate for large trim changes that some models require, especially at slow speeds when elevator effectiveness begins to diminish.

Nice piece of gear, but I would stick to using it in rate mode for elevator.

KennyMac

Aero65

My Feedback: (2)

Hi Harry

I have flown the Guardian in HH on my MB339 for testing. I had it in low rate mostly a non event, at high speed it just kind went where you pointed it if the plane could hold it aerodynamically.
I have a Gen 1 Skymaster MB339 that is pretty heavy 43 lbs Dry approximately so with the PST 1300R it doesn't hold much for long lol.
Our field also has a very tight pattern so its hard to do long legs to see how some of the HH worked.

It made 4 points easy, I was also able to land it in HH mode without issue, as you have seen as long as the gain Is low enough it won't drive the plane to stall.

I don't think that It will be super successful in killing small trim changes, I believe that over time the plane will still drift a bit especially as you may not be generating much acceleration, or angular acceleration in that situation.
it should dampen big changes like putting flaps down at high speed ok, but after things settle down I still think and out of trim bird will feel that way.
(HH really reduced the amount of elevator I had to hold during the 4 point so for that trim change it did work well)

During normal high-speed flight I felt the plane felt notchy in pitch, It was hard to put the plane in a level flight attitude that I was satisfied with. It was always climbing or diving slightly

Here is my Mig-21 from global 6 oz tail heavy during its maiden Guaridan in normal mode. https://www.youtube.com/watch?v=6FLoY3bz5i8
Would have been real fun without the Gyro lol.

I liked HH in some situations it would be nice if we could turn it on and off like the IGyro.

With the same plane I also tried HH with a Futaba Gyro on pitch only to try and get the MB339 to hold a commanded Angle of Atttack, didn't work too well the plane kept wanting to pitch more and more up it did not hold an attitude as I had hoped. It was to
scary to continue with that line of testing so I stopped that experiment.

Been playing with this unit pretty neat so far, have not put it a jet yet.
http://www.bluelight-tech.com/

Jack Diaz

My Feedback: (1)

Art, I don't have elevons on my Rafale.
I have separate elevators and ailerons.
Canards is an aux channel mixed to elevator. Both canards are connected to a Matchbox for reversing and travel.
Guardian is connected to the canards matchbox.
I have a regular gyro on the Rudder only. For some reason, Rudder gyro corrects any aileron wing rocking on the Rafale. I don't feel any need for an aileron gyro.

Unfortunately, I have not been able to test anything, since we are going thru a very tense and dangerous political situation after the recent elections.
When safe to get to the field I will test and post.

If you plan to use the Guardian, I recommend to program it with your PC.

Jack

Jack Diaz

My Feedback: (1)

Harry, it is quite hard to explain "feeling" with words (at least for me).

You have to try it and see if you like and if it really helps. Start with low gain.

Jack

Art ARRO

My Feedback: (5)

Jack D., thanks for your timely response to my earlier questions regarding the use of the Guardian for my SMGripen. Currently the canards are mixed in the transmitter to the elevator function and I have a JR rate gyro for nose gear steering. Will try to adapt the Guardian on rudder, and elevons initially, and then try to mix in the canards. I'll use a PC for programming the unit.
Keep your head down and stay safe. I've had my years of living dangerouslyduring similar "disturbances" in Argentina, India, Thailand and Viet Nam. Take care andI appreciate your response in these tense times.

Art ARRO