Craig B.

just read above post again!

JohnMac

Yes, I realise that using rudder with ailerons is "Proper" flying, and I have been doing it for nearly half a century with full size and model gliders. But for you to say NO, to my suggestion of aileron differential is incorrect. Many full size aircraft use this fix and have done so throughout avaiation history.
However, your answer has nothing whatsoever to do with my post.I was trying to make two points:
1) I doubt if many jet pilots have ever experienced adverse yaw with their jets. This occurs on high aspect ratio wings and jets are mostly low aspect ratio designs. However a lot of jets suffer from Dutch roll which is a different thing, and is acting in the yaw plane due to insufficent directional stability.
2 )Swept wing jets however, have significant yaw roll couple, and the Dutch roll comes from this. A Yaw damping gyro will help fix this, not a roll damping gyro.

That said, if someone is flying a high aspect ratio jet, such as an airliner, then flying with rudder and ailerons to produce smooth coordinated turns would be exactly the way to go.

bobg

I must talk to Ali or Davy this weekend at Weston to see if they have LEG gyros ...prob need one for each leg !!!</p>

Ali

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Bob, feel free... Looking at the weather forecast, I should have plenty of spare time [:@]
You guys already have the perfect solution for your requirements , and have been exporting it worldwide for years!

Nhalyn

Gyro don't fly yhe plane for you, and gyro are not the perfect answer for all the flight domain of the plane, but it's a great help to keep stable a plane that should be difficult to fly without a gyro, as on copters. I remember a friend flying a huge 4 turbine engined Airbus 340 without gyro on beginning, and that was sport. With a gyro on yaw this plane is astonishing. Even the real one can't fly without the 3 axis gyro because of severe dutch rool. You have choise : enormous rudder but poor cruise consuption performance, or smaller with gyro.

I remember my start in copters with poor quality gyro and servo with no good settings... That was a shame and stressfull to fly this copter, and I crash it some times. One day, after an other crash, I buy a Futaba GY401 gyro with dedicated "rudder" speedy servo : that was wonderfull ! In fact I was good to fly copter (that was my thought...). My only work now was to fly the copter, not to spend 50% of my time to make piloted stabilization, in fact more PIO that stability... (PIO : pilot induced oscillation)

For your choice : I use futaba gyro for a moment now and it's great and validated ! GY 351 is from the same generation and basis than GY240, GY401, and other, that are best sellers. You will not be disapointed with one of these.

JohnMac

Ali, that is the best piece of technical advice on this thread. Application certainly smooths out my flying and increases pilot confidence, but if I increase the gain to much, I get adverse yaw, roll and pitch, and thats when I am not flying. By then however, who cares?
Got me wellies.

Ali

My Feedback: (5)

Thanks John.
I am with you on your findings. I also find that I cant switch the heading hold off on that particular installation... No matter what I do, I always seem to lock onto to a direct and locked
in course to the nearest Kebab shop, no matter how much the setting on the input channel.

Xairflyer

My Feedback: (1)

NO! NO! don't let him near that stuff, we still Haven't forgot what happened at Offaly Jets

SpiderJets

.

Xairflyer

My Feedback: (1)

There is a reason, top pilots use gyro's, because they work and help to make the plane fly better. Some aeroplanes like twin fin types will fishtail at certain speeds, a gyro on the rudders will help eliminate that.
I can see lots of benefits for Aileron gyros, from just being able to fly the plane straight and level from one side of the field to the other in gusting conditions, to helping with keeping wings level and preventing a wing drop on landing.
Nosewheel steering is one area I have used a gyro, as we used to fly from a narrow only 3M wide tarmac strip and it was great at keeping the model from wondering off it during takeoff.

Some of you guys need to actually experience what Adverse Yaw is, by sitting in the seat.
I have been in involved in new aircraft type approving from the structural load tests to flight testing. These being the Home/kit built types, and one of them I have flown, has a lot of pronounced Adverse Yaw, to the extent if you roll the wings left without using any rudder, the left wing will drop but it wont turn, the nose will point up and to the right, the slip ball will shoot to one side and you will fly along basically in a streight line in that attitude.
Due to the nature of the drag it will be descending but that can even be stopped with the correct balance of power. So flying this aeroplane you always lead with rudder to make it turn, something that all pilots are taught to make a proper balanced co-ordinated turn.

To help (not always a fix) every fullsize type I have flown has aileron differential, I have actually flown one type that had no down going aileron at all.
On another type we increased the height/area of the fin/rudder to help with adverse yaw as an aircraft's natural directional stability plays a big part in preventing adverse yaw as well.

Couch Potato

Does the C-ARF EuroSport have any tendancy to "Dutch Roll" (at low speed/high alpha ?), I recall deltas can do this.

I suppose a 351 gyro with dual i/p & dual o/p would do the trick for elevon control (1 servo per wing)

I did a search on youtube for Dutch Roll but all I got were tutorials on how to roll narcotic cigarettes !

Nhalyn

Yes, GY351 is typicaly the thing to use when you have such a problem on a delta.

Here in france some guy have try gyron on rudder of Dassault Rafale, but this have minor effect on dutch roll as rudder is small or ineffective at low speed.

Johnnie Red

Truth hurts huh?

As far as which models I fly check my gallery + 150 more models that there aren't inside there.

http://www.rcuniverse.com/community/...y&memid=294785

I must admit that the only reason that I would use a gyro is dutch roll; and only.

Real F-16 are flown with flybywire so you can't mention them as an example.

I am a ppl pilot as well so I know what I am telling you about adverse yaw.

I also fly big warbirds the last 25 years with a lot of competitions, so ignorance is out of the question.

You will remember my sayings when you will drill a hole in the ground with your precious model!

J.R.

landeck

My Feedback: (1)

Craig B., outstanding post!

Bruce

Craig B.

Johnnie,

Seems you are in the minority here my friend. Lovely gallery you have there, some really nice models, but I could not help notice that there is not one jet in there!![X(]

Your fellow countryman had already given you away though, so I knew you were talking with little or no experience of jet flying.....

I don't mind taking advice from experienced guys (ie. jet modellers) but when a guy with no jet experience jumps on here, hijacks the thread and starts giving everyone the wrong advice based on a lack of jet experience, I think that's pretty funny!

Yeah.....maybe not


This thread is for people interested in using gyros, not for those looking to bag the concept. Perhaps you should start your own thread for that. I am guessing it will be a very short thread.


Bruce,

Thank you. Just trying to help out with some relevant information based on experience.


Craig.

socshooter

My Feedback: (45)

Dude, Don't believe everything that is written in Wikipedia...

Jgwright

This has been a very interesting debate on adverse yaw and differential aileron, but little about how it links to the use of gyros. Perhaps my experience will help. I agree with what John Mac, Craig, Xairflyer and Nhalyn said and several posts have very clearly stated what adverse yaw is. When we flew the Horten flying wing for the first time I really was unaware of its importance and when I set up the ailerons for its first flight I set one wing with equal amounts of up and down aileron and really in error set the other with more up than down. The plane of course does not have conventional rudder but has drag rudders. (Which have turned out not to be as effective as thought.)
With the first flight the takeoff was perfect but Dave Wilde who did the flying soon reported that he could only turn left and it just would not turn right. Using considerable skill he managed to fly the plane with differing size left hand circuits till he could line up with the runway and land perefctly just as the engines were running out of fuel. If was in the debrief afterwards with my German friends that I realised the need for differential aileron movement and now have 75% up to 25% down. The plane turns perfectly in both directions after setting them up.
I had a ACT Fuzzy pro gyro on ailerons which was in use for all flights. The gyro never made the plane unstable, in fact the reverse.

Clearly experiments on differential aileron settings need to be conducted with great care and preferably with the effect set on a switch so it is makes matters worse it can be switched out. What I can say with certaintly is that gyros do work and that they have not ever caused a crash.

If you had seen Mark Hintons AW Cougar flying yesterday you would have seen the benefits. It was absolutely rock steady in all parts of the flight envelope in gusty conditions. I said to Mark how stable it was and it must have a gyro on ailerons and he just smiled and said they were on all axis. Similarly Dave Wilde flew his small FEJ Rafale with a gyro, this model has now had over 100 flights. It has gyro on ailerons and makes it nice and stable particlarly on landing when they can wallow about as the nose is raised.

I think it is time for the Greek pilots to buy some and try them rather than scaremonger about something they have not tried.

John

PHIL GREENO

I have watched this thread with great interest as I have just installed a Futaba GY351 to my Carf Hawk,not to the ailerons but to the rudder/nose leg.

Before I give my reasons for opting for gyro on rudder /steering my opinion on the comments about adverse yaw due to aileron deflection from our Greek freinds just do not add up.

As stated above by others adverse yaw due too much down aileron deflection is very unlikely on our jet models.

Most have low aspect ratio wing (unless you build a scale U2) with small aileron size and very small travel compared to slower flying 3D/IMAC models with very large control surface area. Our landing speeds tend to be higher than most sport/scale models(boomerangs accepted) so normal yaw stability at safe landing speeds will stop any adverse yaw if any, once you are on your finals.We tend to only use small aileron movement to keep the wings level just before touch down and I have never noticed any adverse yaw before touch down on my Hawk.

Adverse yaw due to drag on the down aileron is only as far as models are concerned a problem with high aspect ratio sailplanes,mainly in tight turns when in a thermal so a large amount a differential is needed together with combined rudder input.

As for the opinon that using a gyro on ailerons will cause you to crash !!!! Well I have no comment only to tell Ali and others that they better put their gyros on eBay quick as they have been doing it all wrong all these years(not).

I have watched Geoff White fly his beautifull Hunter many times and it flys so smooth as if on rails with perfect landings.Enough said.

The reason I am using the GY351 on rudder nose leg is to make landing easier mainly after touch down while on roll out.

My Carf Hawk is a delight to fly with no dutch roll or tail wagging during normal flight or on the approach but once all three wheels are in contact with runway and brakes are on yaw stability reduces with speed and if you have a strong cross wind (seems to be the norm at all our jet meets over the last two years) the model will tend to want to weather cock into the wind.This can be tricky if you are too aggresive with opposite rudder.I saw another Hawk flyer flip his model over on roll out with too much rudder at a classic jet meet last year.

So I have fitted the GY351 to rudder/steering with low gain to start with as I have used all 12 channels on myDSX12 with no spare input available for gain adjustment.

I have yet to test fly it with the gyro fitted so I will keep you all informed on my opinion.

Phil.

DelGatoGrande

My Feedback: (23)

This classic "under the belt" hit ,it should be used to threads that need exclusively only rc jet operators opinion.
Other than that it only looks like a desperate try to scare away someone.. unless you can explain me what's the difference between a "jet models" aileron and a "prop models" aileron and J.R. cant give his opinion.


Hello John.My english are not the best but i will try one last time to make another post in this thread and
explane one setiuation that adverse yaw and aileron gyros are conected!!


Crosswind landing and gyro on ailerons:

Before touch down close to stall speed, a crosswind will lift high the right wing.
The reaction of the aileron gyro is to give right aileron to level back the wings.
This means that on the wing that drops that aileron will move down as gyro comants.
This downward -deflected aileron generates more drag in this low speed that pulls that wing back causing adverse yaw = redusing more the speed in the wind of this falling wing=droping it even more =stall it = crash.

Here you go.A gyro on aileron caused crash because it did what it sapose to do.

The rules that apply during landings in a near-stall or stall condition are simple as that .
Use rudder to corect any wing-droping tendencies along with ailerons ,and not a gyro on ailerons.

Gyros spesialy during flight will only hide you small warnings from promblems geting bigger till its too late.
As for the best use gyros,i know some "best" over here , hiding there crashes at any cost ....and never admit there mistake.

But at the end of the day i will always wish you all no crashes and me to be wrong!

...gone to fly mmmmmm

HarryC

My Feedback: (1)

Could not be more wrong!
H

Jgwright

George

You really have to try a gyro before you make statements like this. On the planes that we have had that were partularly difficult to fly we would as a normal procedure turn the gyro up to max on approach to hold the wings steady especially when in crosswinds. You have to be aware though that all model will stall at some point and some are prone to drop a wing. In our experience the gyro delays the point at which a plane may drop a wing due to stall.

I am beginning to think you misunderstand what the gyro does. The wing that moves uncommanded down will get a signal to drop the aileron and at the same time the wing that moves up gets a similar signal to move up. This levels the wing and it done in a split second. The gyro does not work on just one surface when used on ailerons.

http://www.youtube.com/watch?v=95cB9qXflLk

This is some video of an old plane of mine flying in a stiff cross wind. It was a very unstable plane and I doubt we could have flown it at all without the gyro. It had a nasty 'Dutch roll' which was dampened out with the gyro. With the tall fin cross wind landings would have been very difficult without the gyro. We always had full gyro on for landing.

John

Craig B.

Hi John,

All very valid points that you have raised. These guys just don't get it and have dragged the thread way off course. Thanks for posting the info about the models that you have seen flying well with them and for the info about the Horten.....interesting stuff and a true test of modelling skills with that airframe...well done to guys involved.

Craig.

DelGatoGrande

My Feedback: (23)

[youtube]http://www.youtube.com/watch?v=ZL7upK2kUqQ[/youtube]

Xairflyer

My Feedback: (1)

I think putting this thread back on track would be for guys who have used gyros to post type used, and where from experience was the best place to mount them, on the CG? in front/behind? as this will effect amount of gain/compensation needed. i.e. for rudders right in the nose will be more sensitive than near the CG.

I used a simple and cheap GWS PG-03 gyro for nosewheel steering, it was mounted vertical on the side of the fuselage just behind the noseleg and has worked perfect once I got the correct gain set.

Johnnie Red

Can you state the right path then? Did you read the whole paragraph? Gatto says when the speed is very low close to stall. Which control are you using? The ailerons? And you are right?????? For one thing you'll be right to use ailerons at that point. And this is only to stall your bird sooner!!!! Rudder is more energy efficient in small speeds and this doesn't imply only in prop driven aircraft but in Jets too!!!! I am out of this thread since we are talking using different perspectives; but guys go get some experience in aerodynamics first and then you'll have a vast knowledge of what is going on. Adverse yaw happens in all planes.