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Wow, what ever happened to airmanship? I had no idea pilots were so reliant on gyros - even for 3D! Well, whatever makes you 'look good'.
And if your landings are 'bouncy', you need better airspeed control (slow down). Or maybe they'll make a gyro for the throttle, too. :confused: |
Originally Posted by eddieC
(Post 11633122)
Wow, what ever happened to airmanship? I had no idea pilots were so reliant on gyros - even for 3D! Well, whatever makes you 'look good'.
And if your landings are 'bouncy', you need better airspeed control (slow down). Or maybe they'll make a gyro for the throttle, too. :confused: |
Nice plane G38...saw one with a military scheme at west Texas warbirds this sept. I talked to Jose with GJC last night for a bit and still thinking about it
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Yeah I've never used one or had a need for it but with the the jet it's more about funky wind at a fly in and the mig dies exhibit that constant tail wag.... Not so worried about that but a gyro would certainly smooth it out
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Thank D Gladwin.....that really helped me to understand some gyro concepts....you know how it is when you deal with something for the first time, it's only easy to the ones that know how it works. Thanks for sharing that David
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That's a bit narrow minded to think we are using gyro's just to look better. But hey the horse and buggy worked great for a long time too! Doesn't mean people shouldn't buy a car that makes things easier. I just want to fly and get my jet back safe. So sue me.
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Originally Posted by Pepperpete
(Post 11633502)
That's a bit narrow minded to think we are using gyro's just to look better. But hey the horse and buggy worked great for a long time too! Doesn't mean people shouldn't buy a car that makes things easier. I just want to fly and get my jet back safe. So sue me.
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Originally Posted by HarryC
(Post 11632659)
That's interesting that they should make that. I have had a MEMS gyro system suffer serious acoustic interference in one of my jets. At 3 particular rpms the noise from the engine was kicking the MEMS gyro and causing it to make massive control inputs. We easily proved it was noise and not airframe vibration by hand holding the gyro system away from the airframe and still it kicked at 3 particular rpms. It is very rare to suffer from it. The same system works fine in other jets and for many people. It must just be that one engine generating just the right noise. I read up about it. MEMS gyros are not solid state, they are tiny mechanical systems so small they can fit on a chip. Being mechanical, a sound at the right frequency can harmonise with the vibration of the MEMS ring and give it a kick. Early MEMS gyros, as fitted to so many consumer devices such as mobile phones, were quite prone to acoustic interference giving false readings and it was well known, so the vibration frequency of the gyros was increased greatly to stop this. However I expect our turbines and their high rpm are capable of generating sound frequencies much higher than those encountered by the normal consumer. An older design of MEMS gyro running at the lower frequency will have more risk of picking up acoustic interference.
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Dan i was advised by the maker of the unit to use the acostic cover. for turbine operation.
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If any gyro needs acoustic protection, my suggestion is DON'T use it. You don't need to risk unneccesary inputs created by this problem when there are plenty of gyros which don't have this problem. Why take the risk ?
I have gyros in ALL my jets, (12) on rudder, N/S and ailerons and none have acoustic problems. My gyros come from Weatronics, Futaba, JR , Powerbox and ACT. |
I recommend to check out this new gyro here:
http://www.bavariandemon.com/en/products/cortex/ Saw it in action last weekend and I was more than impressed by its performance during really nasty wind conditions. It is also very easy to setup. |
Do the gyros need to be mounted directly over the axis of rotation in reference to the airframe?
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Originally Posted by n8622t
(Post 11633729)
Do the gyros need to be mounted directly over the axis of rotation in reference to the airframe?
No. But obviously, they will become more sensitive as the approach the center of movement. On the RC heli's... we use to mount the gyro directly under the main shaft. (way back in the day) But now... we mount it behind the shaft. The only thing you need to do, is mount it in the correct orientation. ie. if you mount it 90 degrees out... it will read the wrong axis. |
Originally Posted by David Gladwin
(Post 11633652)
If any gyro needs acoustic protection, my suggestion is DON'T use it. You don't need to risk unneccesary inputs created by this problem when there are plenty of gyros which don't have this problem. Why take the risk ?
I have gyros in ALL my jets, (12) on rudder, N/S and ailerons and none have acoustic problems. My gyros come from Weatronics, Futaba, JR , Powerbox and ACT. David, Joachim only recommended the acoustic cover, In typical Germanic Fashion I'm sure he is erring on the safe side with this recommendation. I know of installations that are working perfectly without. |
Originally Posted by Dr Honda
(Post 11633734)
No. But obviously, they will become more sensitive as the approach the center of movement.
In a rigid body, the gyro sensitivity is exactly the same no matter where you put it. A gyro senses a change in the angle, it doesn't measure movement. Since all parts of a rigid model will rotate the same, the gyro sees the same thing no matter where it is. In a flexible body the gyro has the same sensitivity wherever it is but the flexing will make it sense the wrong things so it may over or under react, such as if you put the roll gyro at the tip of a long flexible glider wing. |
Originally Posted by Dr Honda
(Post 11633734)
The only thing you need to do, is mount it in the correct orientation. ie. if you mount it 90 degrees out... it will read the wrong axis.
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..
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Let’s go back to the original question.
Originally Posted by n8622t
(Post 11632180)
I have my first scale Jet, a GJC Mig-15, after flying the ShockJet for two years. Couple of guys say "get a gyro". Do I really need one for this model…. Im thinking that if I do get a gyro it would have to be one that will help with extreme crosswind landings. I cant really think of any other reason to have one.
Since the Mig will be stable, the gyro is not there to make an unflyable plane flyable. Damping out turbulence is a worthy use of a gyro, the main one being roll so that the gyro helps to keep the wings level. This makes all the flight look nicer and helps when landing in turbulence regardless of head on into the wind or in crosswind. The gyro will not do the crosswind landing for you but it helps prevent the wings rocking about. I suspect that the reason a couple of guys said get a gyro is that swept wing planes are prone to Dutch Roll. Dutch roll starts as fishtailing in the yaw axis, and the dihedral effect of a swept wing makes it rock the wings in the roll axis in response to the yawing. The yawing and rolling are out of phase so the plane looks like it is in a drunken waggle. If you stop the fishtailing, you will also stop the wing rocking. The full-size use a “yaw damper” which is essentially a rudder gyro system and they have been doing this since the early days of swept wings, long before modern fly-by-wire. It is not possible for the pilot of either full size or model to react fast enough or for the long periods required, to manually stop the fishtailing. That is why rudder gyros are used. Watching from the ground we often see the wing rock much more than we see the fishtailing, hence many model fliers’ tendency to fit an aileron gyro rather than a rudder gyro, with the advantage that the aileron gyro helps more in turbulent winds. Your Mig may or may not suffer from noticeable fishtailing or Dutch Roll. If it is noticeable it may still be fairly small and not bother you. If it is noticeable it does not affect the handling or controllability of the model, using gyros to stop it is purely cosmetic and no-one should be made to feel they are somehow not a good enough pilot, by people who don’t seem to understand the situation such as the post at the top of this page. |
Originally Posted by David Gladwin
(Post 11633652)
If any gyro needs acoustic protection, my suggestion is DON'T use it. You don't need to risk unneccesary inputs created by this problem when there are plenty of gyros which don't have this problem. Why take the risk ?
I have gyros in ALL my jets, (12) on rudder, N/S and ailerons and none have acoustic problems. My gyros come from Weatronics, Futaba, JR , Powerbox and ACT. |
Originally Posted by HarryC
(Post 11633796)
Let’s go back to the original question.
There are 3 main reasons why a gyro might be needed: the model is unstable; Dutch Roll; damp out turbulence. Since the Mig will be stable, the gyro is not there to make an unflyable plane flyable. Damping out turbulence is a worthy use of a gyro, the main one being roll so that the gyro helps to keep the wings level. This makes all the flight look nicer and helps when landing in turbulence regardless of head on into the wind or in crosswind. The gyro will not do the crosswind landing for you but it helps prevent the wings rocking about. I suspect that the reason a couple of guys said get a gyro is that swept wing planes are prone to Dutch Roll. Dutch roll starts as fishtailing in the yaw axis, and the dihedral effect of a swept wing makes it rock the wings in the roll axis in response to the yawing. The yawing and rolling are out of phase so the plane looks like it is in a drunken waggle. If you stop the fishtailing, you will also stop the wing rocking. The full-size use a “yaw damper” which is essentially a rudder gyro system and they have been doing this since the early days of swept wings, long before modern fly-by-wire. It is not possible for the pilot of either full size or model to react fast enough or for the long periods required, to manually stop the fishtailing. That is why rudder gyros are used. Watching from the ground we often see the wing rock much more than we see the fishtailing, hence many model fliers’ tendency to fit an aileron gyro rather than a rudder gyro, with the advantage that the aileron gyro helps more in turbulent winds. Your Mig may or may not suffer from noticeable fishtailing or Dutch Roll. If it is noticeable it may still be fairly small and not bother you. If it is noticeable it does not affect the handling or controllability of the model, using gyros to stop it is purely cosmetic and no-one should be made to feel they are somehow not a good enough pilot, by people who don’t seem to understand the situation such as the post at the top of this page. Thanks HarryC yer putting me closer to realizing I may not need anything bur flight time |
For Eagle Tree Guardian users
Note that there is a thread on this device in the RC Radios, Transmitters, Receivers, etc forum entitled "Eagle Tree Guardian 2D 3D Problem". It seems that some users have experienced problems with uncommanded 2D/3D modes and Normal/Elevon settings. A factory reset is advised and should be implemented. Note that I have an ET Gurdian unit but have not yet installed it in one of my jets. As a precaution I do plan to perform the factory reset and thoroughly test it in a prop or EDF model first. Art ARRO |
There also is a thread listing the latest software updates from eagle tree. You can subscribe to it and get an email on any new up dates. I typically will download the latest version and install it in all my onboard units. Also I have the gyro assigned to my LH slider (DX18) so I can turn the gain down to zero which shuts it off. I like turning it off when not needed. I am running only rudder and ailerons in default 3D rate with heading hold turned off.
Vin... |
Vincent,
Thanks for the update on the ET Guardian. That is how I plan to set mine up-first in a prop or EDF testbed then a turbine jet-after the factory resets/updates. Art ARRO |
Why not pay a little bit more and go with a product that is already proven ? The powerbox iGyro is proven, you can install it in different positions and it doesn't need a noise blanket. Plus it's a breeze to setup.
The GPS sensor records the airspeed in every flight situation and passes the information to the iGyro, which exploits it to adjust the gain to suit the model’s current speed range. This effectively prevents the model being overcontrolled and oscillating at high speed but at the same time allows optimum flight path correction during slow landing approaches in gusty conditions. |
The Eagle Tree Guardian is proven in my book. I have three of them all in expensive jets and have had no issues at all. Like I said I keep up with the factory software up dates and have the gyro on a slider so it can be turned off or the gain turned off completely if needed. Somebody mentioned to me about trusting a $70 gyro to run a 10k jet but we do put a lot of faith in a $100 rx so whats the difference?? my units have worked perfect for me set on 3D rate with heading hold turned off.
Vin... |
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