How Best to Stabilize - Page 5 - RC Groups
 Dec 05, 2012, 03:24 PM Registered User My first thought was to set it up like a delta wing. With the vertical canard, as the rudder. With the rudder mixed to aileron on the controller. I still think a simple rate gyro would work for roll.
Dec 05, 2012, 03:31 PM
Rocket Programmer
Quote:
 Originally Posted by BluenosePacific I would think a first step would be to determine the control variables and their relationships to one another, no?
Well yes, to document that situation is important - we know kinda what it is, but it's not written down, and I think this is one case where writing it down and making pictures will help. Do you have any additional drawings you can share?

Then I think that yeah, the next major step would be to model that control system in some water, to see how it reacts. I'm not talking about small-scale models, I just mean mechanical test objects, so you can figure out each problem in isolation as much as possible. Figure out how "if this was attached to a boat" how it would work. Then you'll be able to see if you need a tail for example, and you'll be able to test specific numbers, such as how much lift you get at given speeds with a particular shape and with different pitch combinations - those numbers might surprise you (for example did you know that a helicopter can stay aloft in certain conditions with negative collective?)

As a programmer, I think modelling is wicked important - solving one problem at a time can sometimes help....

 Dec 05, 2012, 06:18 PM Mariner BC Canada Thanks for that 2501, we have similar thinking you and I. I have lots of additional drawings but they are evolutionary in nature and would really only be a trip down memory lane. Would you like to see them? Yes, a helicopter can stay aloft under negative collective in, 1) a descent from sufficient altitude, 2) given sufficient washout in the main rotor blades, 3) providing there is sufficient camber in the main rotor, 4) during inverted flight providing it is certified for such, or 5) in a sufficient up-draft :-) I can calculate lift, drag, etc with accuracy acceptable to the design parameters besides, I don't have the test facilities to run tests. The one drag measurement I will make is that of the bulb as there is a huge lack of data for calculating it. A simple side tow test in "clean" water with an in-line scale will suffice. No more hour long videos okay? Lets get this party going. Last edited by BluenosePacific; Dec 05, 2012 at 10:29 PM.
Dec 05, 2012, 10:17 PM
Quote:
 Originally Posted by Roto Rob My first thought was to set it up like a delta wing. With the vertical canard, as the rudder. With the rudder mixed to aileron on the controller. I still think a simple rate gyro would work for roll.
With the hugely limited power available a delta wing would not be beneficial and the added drag penalty would be counter-productive.

Referring to the canard as a rudder is misleading.

It doesn't act as a rudder at all.

It induces zero yaw effect.

If anything, it may induce a small amount of drift, slip, whatever you'd like to call it, transfer even.

I'm sorry Roto, but I am not looking for design advice, I'm looking for a stabilizing system for my design.

How would a rate gyro keep this thing up with no point of reference?

I can see how a heading hold one would.
Last edited by BluenosePacific; Dec 05, 2012 at 10:39 PM.
 Dec 05, 2012, 10:46 PM Rocket Programmer The rate gyro matches actual rotational rate with requested rate, while allowing for drift, so it tends to give a more natural motion. On a helicopter, the rate gyro causes the tail to follow the helicopter around more naturally in a banked turn without the need for a lot of correction from the pilot, so it feels more like a full scale helicopter. With the heading lock gyro, you bank into a turn and the helicopter will side slip, as the gyro resists turning, so you have to carefully turn the tail yourself as you go through the turn. So, the rate gyro feels more natural, but the heading locker allows for acrobatic tail behavior which is impossible without some method of resisting the tail's need to weathervane. So we can fly backwards and sideways at high speeds. I don't think you need that capability.
 Dec 06, 2012, 12:03 AM Mariner BC Canada My rear rotor blades from a Bell 206L arrived at my door step this evening. They are candidates for the forward wings on the bulb. 2501, I'd like to start researching that board your recommending but there was some confusion over which one it was. There could be three axis or perhaps only one in need of sensing. You were mentioning one board with the components separate in the future if need be. I've read through your posts several times, would you mind making that recommondation again? I'd like to start familiarizing myself with it. Thanks
Dec 06, 2012, 03:08 AM
Registered User
Quote:
 Originally Posted by BluenosePacific -----I'm sorry Roto, but I am not looking for design advice, I'm looking for a stabilizing system for my design.----
 Dec 06, 2012, 05:40 AM No best,just better stabilizer,jeje
Dec 06, 2012, 11:44 AM
Rocket Programmer
Quote:
 Originally Posted by BluenosePacific 2501, I'd like to start researching that board your recommending but there was some confusion over which one it was.
I didn't recommend anything specific, just was saying I thought you probably will need the advanced programming options, and suggested that Arduino-based stuff might be the easiest to work with. I think Rob is suggesting you might try a simple, cheap rate gyro first - this seems like a good idea, because I'm only assuming that you'll need advanced programming options because it's a wildly different situation. There is a possibility that a cheap rate gyro might be fine though, and trying that before going down the long road with extremely customized stuff seems like a good idea. Single-axis rate gyros are pretty darn cheap - I think HobbyKing has them around \$5-20
 Dec 06, 2012, 12:34 PM Mariner BC Canada Roto Bob, Thanks for the suggestion. I've reread your posts and my own. I made it clear in my opening sentence what I was asking for.
 Dec 06, 2012, 12:39 PM Mariner BC Canada Okay, Any specific, i.e. model number, manufacturer, Hobby King cheap rate gyro you could recommend? I guess anything in the \$5 - 20 range. Disregard.
Dec 06, 2012, 12:59 PM
Rocket Programmer
Quote:
 Originally Posted by BluenosePacific Okay, Any specific, i.e. model number, manufacturer, Hobby King cheap rate gyro you could recommend? I guess anything in the \$5 - 20 range. Disregard.
They are all equally crappy, but people seem to have good luck with the Assan and the GY48v. I can't access HobbyKing from the office or I'd send you a link.
 Dec 06, 2012, 01:41 PM Mariner BC Canada And a servo tester to go with it. And a Lipo battery for it and the servo. I understand there are some controls on the tester. I may be able to use one for centering adjust while making way. This may provide banking while applying rudder in turns.
Dec 06, 2012, 01:58 PM
Rocket Programmer
Quote:
 Originally Posted by BluenosePacific And a servo tester to go with it. And a Lipo battery for it and the servo. I understand there are some controls on the tester. I may be able to use one for centering adjust while making way. This may provide banking while applying rudder in turns.
Servos generally run on 4.8-6V - a Lipo will be too much power for running directly into a servo without a voltage regulator - a 2-cell Lipo is at 8.4V at full charge and that will burn up a servo immediately. So, I suggest a receiver pack made from 4-5 cells NiMH or NiCd for powering the servo.

The servo tester was suggested because you need a way to send a position signal to the gyro (which is then sent on to the servo after adjusting for error) - since you don't want to set up an entire RC system to control the servo/gyro. You could use it as a steering wheel, not just for trim.
 Dec 06, 2012, 02:17 PM Registered User I think he planned on high volt servo's. The servo tester alone, will not work on a gyro that needs a remote gain signal. The Delta wing configuration mentioned before, is a function of a multi board. Most of the Multi boards software was writen for Airplanes, helicopters, and multicopters, so the terminology is not likely to match with nautical terms. Was just a proposal to get the multi type board going. It could be set up as a delta wing aircraft. This would change depending on what surfaces he wanted to use for control. It could be also setup like a jet with Tailerons. This would allow the main lift surfaces to be set as ailerons, and the aft control surfaces to be set as elevator. A rate gyro's point of reference is its current position. It sends a signal to resist a change in its rotation.