yellowufo

Ok i want a gyro controled front wing on my airboat.... i have zero smarts on using gyros..


Do i need another channel on my radio? Or can it run on its own... anyone with smarts on this subject please chime in thanks..

Altered1

You would usually use a gyro on the rudder. What is so drastic that you want to do this ? I don't know that a front wing is going to react fast enough ?

yellowufo

Seems it BLOWS over easy... may b the 29.5oz weight and yes i know gyros r used on rudders if it can work on that axis n reasn y it wont work on the vertical.

Jeremy_H

From looking into this myself it should be possible, it's just a matter of positioning the gyro so that it's seeing the pitching movement
(assuming you're using a single axis gyro). On mine we're thinking front wing and trim tabs (well, a different kind of tab, but the same effect). Reaction is in real time, only the servo speed limits that, so a fast servo and arrange it so that it does not allow the boat to get so far out of shape that it's too late, more proactive than reactive I suppose. I'll not be getting to it for few weeks, so will watch your progress with interest.

yellowufo

Im still in learning mode and i do à lot of reading before i pull the trigger... so you will b done before me...... so a single axis for the vertical.... can u point a gyro part out that would work

Jeremy_H

Well it's all new to me too, I'll be doing some more research with my local outlet tomorrow. But, at the moment I believe the idea is to use a 'headlock' gyro. These are intended to keep helicopters straight independently to the rudder action of the tail rotor, so it resists horizontal plane rotations not inputted by the pilot. I guess that inputs by the pilot overide the gyro's activity to permit steering. By using such a gyro on it's side the horizontal becomes vertical ( gyro simply senses it's orientation in space and reacts to changes) . The unit I looked at in the shop simply fitted between the receiver and the servo that reacts to the gyros intructions, it's up to you to arrange the servo's activity resulting from that. I guess that the gyro's position dictates the degree of servo movement, so we would have to suss just how much that needs to be on the control surfaces (wings etc). Start with a trialled neutral position, which dictates the gyro's orientation in the boat, and when the gyros sees a deviation from that we need to ensure the movement of the control surface, including it's size and efficiency is able to adress the deviation detected and bring it back to neutral. In practice though the thing should put in real small constant trims so that mass deviation does not occur, that's the point of them of course.

To be honest this is all loose stuff that needs consolidating, I'll know more tomorrow when I've spoken to the shop dude and I have one to play with. I'll let you know.

This is the sort of thing, this one can be adjusted for rate under way

http://www.ebay.co.uk/itm/NEW-RC-Hel...21013723935%26

yellowufo

Dude it is "stuff" that i thank you for spending the time to share, it reafirms my thoughts

Now i will search for a wing design and size, i have built a static wing that is working on solid ground it slowed the blowover pretty well, i have yet to run it on water

Altered1

Under a kilo? that IS light!

This can be done, you need to mount the gyro in the correct orientation.

yellowufo

And it is still heavy it should b 16-18 oz auw

Jeremy_H

OK, whilst a video is trundling through processing on my archaic computer I'll tell you where I am.

In effect, what I was thinking of above is correct. I now have a gyro, and frankly it's making me think of all sorts of opportunities.

In the video I fire up the radio on my proto twin boat with a spare servo in sight. On this particular gyro (maybe the same for all) it takes a few seconds from power on for it to set itself, the model must be still during this. A red indicator comes on when it's happy. I then move the gyro in the plane it was designed to operate, horizontal movement around a vertical axis, and you can see the servo reacting to the movement. I then move the gyro to a position where it detects pitching movement around an athwartships axis, or across the boat, which is the way to control take offs. So looking forward, the gyro has been tilted to the left or right. I then power it up again and show that pitching movement now moves the servo.

I've got the gyro set to maximum sensitivity gain for this demo, so that servo movements are obvious, but this makes it twitchy. On this device, you can either dial that in by adjusting an inset pot screw, or control the gain from the transmitter. In my case I'll be using the left stick left-right movement, which is nothing on the airboat at the moment, but in the Uk would be an aeroplane rudder. By using the electronic trim switch, which on this radio gives me full servo movement, I will have gain adjustment under way by punching the trim switch.

Looking at this video it comes across as a setup, like I'm working the transmitter off screen . Take it from me, I'm not .

I'm immediately thinking of fitting one to the rudder on an airboat as well. Weathercocking is clearly an issue with air rudders if there is little in the way of spray rails or other aligning features on the hull, and I'll be trying this first, because my proto twin boat is not likely to suffer from trying to be airborne, hence pointless for now. It'll be interesting to see if the gyro can keep the boat on a drifting path automatically. My final boats though will however probably benefit from pitch control, but as I said I'll not be getting to that for a few weeks.

Add a third gyro and you'll have all three axis covered. So long as the designed control surfaces are effective and gel well with the gyro, the boat could be made to sit flat whatever it's doing. We'll see perhaps.

I'm off to put some more coal in the computer, I'll post a dedicated link to the vid as soon as able.

Jeremy_H

Here you go:

http://www.youtube.com/watch?v=CYo0UgEnCow&feature=youtu.be

yellowufo

I have sen videos of gyro controled rudders and they really do a good job i can see no downside to using one for heading control, glad to see there is a gain control on the unit...

After seeing the movment i have a pretty good idea about the wing size.. nice work and again thanks so much for your smarts....

Altered1

Here is another option - control of front wing linked to throttle position. - more throttle, more wing.

http://www.youtube.com/watch?v=fnGVLOHC90Q I'm trying to find a vid that I saw where the gyro was connected to the rudder - gyro on and off is displayed.... stay tuned

.... here it is:
http://www.youtube.com/watch?v=g5hgjucvKd8 Thanks to the originators of the vids

*delete M i k e u p delete*

I have a ?. Why use a gyro at all as you want to glide in a airboat and do crazy things like donuts and the like. If you want to go straight all the time and take the fun out of it, use a regular boat and zip away. The fun is to build or buy one and revamp a airboat just to see what it will do. If you read airboat forums, the first thing is asked , what can I use to upgrade to go faster. When I go airboating, i'm told i'm having to much fun gliding and doing donuts and the like. I use electric motors and lipos as noise ordinance is in place and allowed to use the ponds. My 2 cts. I watched the video and saw straight line running and if that is their choice, that's great. Now it ran great and am glad it did great.

Altered1

I'm with you mike, but I can see the advantages of a rudder gyro in challenging conditions like high wind or over bumpy ground.


This thread started because the TS wanted to stop his boat from blowing over.... by a gyro driven front wing.


You can still do donuts and slides with a gyro, it just averages out the direction inputs. A hard right or left rudder input will still do a hard turn.

*delete M i k e u p delete*

Thanks for straightening that out! I can see the front wing used for blow-over controls. I would probably add weight in small portions till blow overs were cured with wheel weights but that's me. I saw the video and noticed the bow had a high rake which would catch a lot of wind. Mine have a long rake and same height in structure from transom to bow and yet when moving out raises a good inch at bow and runs on the last 6" on a 19" length. Enough out of me, glad you informed me about the gyros. Thanks!

Jeremy_H

I looked at your videos and that's a challenge indeed. Ideal! We like challanges

A couple of things come to mind.....First off I'd be inclined to pursue the weight idea to take the bulk of the problem out. A gyro will probably help for sure from what I know, but some careful thought would be needed to get the wing right, as that bow is a large lift area and any wing would have to be able to compete with that.

As the wing has to have a servo, and between that the gyro and a wing we are adding weight, it might be good to see if any initial improvement with weights alone could be done with the gyro/servo/wing weight in mind, so that they would replace the weight added. Meaning that the weight of the kit would probably do most of the work, and a gyro could kick in if it was getting more out of shape. I'm guessing you're going to need a mini servo, and a nice lightweight wing. It would be cool if the wing pretty much sat flat on the deck until the gyro lifts it, but that rise on the bow would mean it would have to deploy a lot to be effective. The ideal position would be to reside on pillars to keep it in the airflow coming over the bow.

Interesting stuff.

Jeremy_H

This is what I've gleaned so far from using this Gyro, I can't report if this applies to others.
Free moving linkages are important, if it can be straight rod links with minimal friction only at the servo and control surface links then all the better.
This gyro uses its own zero point on the servos, it ignores any centralising signal from the transmitter. So having fitted it, the transmitter must have trims neutralised, and the control surface must be adjusted to neutral using control rod length.
In it's applied use as a headlock servo it works with the transmitter in a particular way. As far as I can detect, as you apply a control input it lets you move things, but it does not go neutral when you let go of the stick, it stays at the place it was moved to. In other words, If I put 20 degrees of rudder on to turn a boat then let go of the stick the gyro will maintain the heading you directed it to. To bring the boat back the other way you have to apply opposite input. This is a bit weird, more like flying a plane.
On my gear I have to select Heli mode to activate the on radio bias adjustment, which means the throttle and rudder are on the same stick. Naturally I use the aeroplane aileron control for rudder on a boat, so didn't pursue that.
The bias adjustment limits the reactivity of the gyro by reducing the scope of movement of the control surface, this prevents over-control leading to oscillations. This also removes the scope from manual input, and if set too high it leaves you no control at all.
It needs an active channel to operate. So in my case, for a horizontal stabiliser, I would use the spare elevator channel. I've yet to try it in an auxiliary or switched channel, like undercarriage or flaps might have to see if these would work, I'll do that soon. the thing is that it certainly does nothing if the channel is turned off on the transmitter, so it needs to see a signal input from the receiver, not just voltage. On my wheel control car rigs the third channel mixture control would be fine.
The control link's degree of movement of the control surface in respect to servo output is dictated by the link offsets, i.e. the distance the link is attached to a control horn from the center of rotation. So better to build in scope for adjustment either side on both the servo arm and the control surface horn. Starting in a central placement we can then get more or less movement out of the servo as required.

In operation I found that it basically takes away corrective control input from the pilot, so on my rudder trials the boat might be following a line being needing the odd input to correct side wind effects, with the gyro on it does the same but the controls are automatic. This has made it tricky to demonstrate, but in vid 4 of my twin engine thing many of those turns are involuntary, it's those that are largely cancelled out by the gyro.

In principle then this will work on our plan of using them to stop bow lift, the only barrier to that is the setting up, which will need a bit of trying and adjusting to neutralise the control surfaces, and to ensure the right amount of corrective action takes place, This feels better than tying down the bias, but so much matters on what you're trying to correct and how extreme it is. The speed is as quick as the servo you attach to it, so consider that if there's a need for a fast response.

More when I fit them for real on the in-line twins.

Got RPM

Some waterprop racers in the NW are using gyros to good effect to prevent blowovers. Their ~40" hydros are running near 50 mph and by controlling the front canard they are preventing blow overs. Adding weight works, but only at a certain speed. Below that speed the boat runs too wet and loses speed and efficiency. Not enough weight and over she goes. Smaller or faster boats will probably not be good candidates for the gyros since blowovers happen too rapidly even for today's low latency systems.

My own experience is limited to rudder control, important for speed runs. A heading hold gyro activated by the third channel keeps me headed in a straight line for the lowest time through the traps at 80+ mph. It requires a decent digital servo to work right.



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