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Old Sep 28, 2008, 01:56 AM
Just one more flight...
RCSuperPowers's Avatar
Pasadena Cal-i-Forn-I-AY!
Joined Sep 2005
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Quote:
Originally Posted by rcgReader
That is unbelievable.

Having a Reflex 3D park flyer where the CoG demands to put the battery directly after the motor. Installed the cheap esky gyro from my phased out Honey Bee King II heli. Mounted on the right side of the fuselage (profile) just above the wing 2/3 from the leading edge.

Gain is set to ca. 55% (started with 25%). Now I can forget about this Center of Gravity thing (what's that? ). Was able to move back my 100 g battery about 2 inches -
was also able to use my old 50 g battery packs without using ballast.

There is no difference in flight characteristics (much slower flight speed now possible) using both packs on the same mounting position.

Thanks Dave for your great work and inspirational videos!

Thomas
There ya go Thomas, thats it, you got it! Pretty fun huh! So you are flying slower cause you can put a lighter battery on with the CG back, very nice.

If you think about it, with a normal airplane (not counting wonderful canard planes) to go UP you must SHOVE your tail DOWN to make the rest of the plane go up. Seems just a little inefficient to me. Canrad planes LIFT the nose to make the plane go up.

But with a "normal plane" (non canard, tail in the back, such as a YAK or F-15 type plane) that is gyro stabilized with a far back CG such as this, you now don't have to shove your tail down so much or at all in some cases to go up. What I mean is, on my SU-35 I am flying with some DOWN ELEVATOR when I am going straight and level, much like the real SU-35 at some speeds. My tail is constantly "floating up" to counter the far back CG.

So get this, to go up, I simply stop lifting my tail - then the nose goes up! Or put another way, to pitch up (not counting a loop) my elevators simply go from a "down pitch" position to a neutral position. Now thanks to the far back CG, my plane goes up with out shoving my tail down like a traditional set up. I am now saving a tremendous amount of drag from not having to shove my tail down to make the rest of the plane go up!

So you will find if you watch your plane, you should have much better float, fly level with some trim down, and your maneuvers will be more responsive and aerodynamically efficient.

Dave
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Old Sep 28, 2008, 02:05 AM
Just one more flight...
RCSuperPowers's Avatar
Pasadena Cal-i-Forn-I-AY!
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Quote:
Originally Posted by Gandalf_Sr
Very cool. I am into helis and am familiar with heli tail gyros, I was thinking about using one on a new plane with active front canards and have a few questions if I may.

1 Are the gyros you're using running in heading hold mode or just rate mode?
2 Do you switch the gyros remotely and/or change the gain remotely?
3 When you go into high Alpha, do you switch into a different mode that has offsets for the canard position?

Thanks in advance.
1) Mine are NOT heading hold, don't have that feature, never tried it. Sounds good though.
2) My gyros are NOT on a switch, I need them on all the time on this jet.
3) Yes, scroll back up the pics I posted, see the one with the writing all over it... CH5 does my canard high alpha, and CH6 does my spoilerons high alpha. When my nose is up at 45-90 degrees, the canards and spoilerons (ailerons) now face back into the wind giving me back pitch and roll control at slow speeds. Once the plane stops, I am relying on just the 3 dimensional thrust vectoring and the gyros to hold it for me. Hovering its the easiest part cause I do nothin at the point.

Also, I have 3 more videos of the this SU-35 on YouTube. The other 3 videos can be found here and are all BEFORE I installed the gyros. They do show how the controls are set up:
http://www.youtube.com/profile_video...=RCSuperPowers
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Old Sep 28, 2008, 06:26 AM
Ted M
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Ann Arbor, MI, USA
Joined Feb 2007
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RCSuperPowers Thanks for the info.

Here's what I know about gyros...
'Ordinary' gyros are rate gyros; they control a servo output and they drive the output so as to maintain a certain rate of turn, the more the stick throw, the faster the rate of turn. If the control stick is centered, then the gyro will be trying to maintain a zero rate of turn and counteracts any movement.

Headhold gyros work in exactly the same way but they have one more major smart. When in the center-stick position the HH gyro still works to prevent movement on that axis but if movement does occur, the HH gyro actually measures angular movement in the controlled axis and drives the servo, not just to counter the movement but also to get the axis back to the actual way it was pointing before it was moved. This is why HH gyros are more expensive.

In the case of helis, HH gyros are used to control the tail. You can be hovering say nose out and a gust of wind can blow on the heli, although this will have the effect of moving the whole heli downwind slightly, the HH gyro ensures that the tail of the heli continues to point in the same direction. Although you can use normal rate gyros on heli tails, they suffer from drift.

I thought about using a gyro on my elevator / canard channel to maintain pitch attitude just as you have done; I was thinking that I would need a HH gyro but now I'm thinking that's probably overkill as you have to keep flying the plane anyway and the drift caused by a much cheaper rate gyro would not be a big deal.

Let me try out a check of understanding... My candidate plane is a delta wing that uses elevator mixed with aileron on L/R control surfaces at the rear of the wing - 2 servos - plus elevator-only canards forward on a separate single servo. Mixing is currently done in the transmitter but I think that, in order to put a gyro in charge of the pitch, I will have to send pitch (elevator) and roll (ailerons) to the plane separately, send the elevator signal through the gyro, and then use a mixer to combine the pitch gyro output and the aileron channel from the receiver to drive the elevon control surfaces and also 'Y' the output from the gyro to drive the canard.

I would be very interested in seeing a schematic drawing of how you've connected it all up.
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Old Sep 28, 2008, 12:09 PM
Just one more flight...
RCSuperPowers's Avatar
Pasadena Cal-i-Forn-I-AY!
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Quote:
Originally Posted by Gandalf_Sr
RCSuperPowers
... I thought about using a gyro on my elevator / canard channel to maintain pitch attitude just as you have done; I was thinking that I would need a HH gyro but now I'm thinking that's probably overkill as you have to keep flying the plane anyway and the drift caused by a much cheaper rate gyro would not be a big deal.

Let me try out a check of understanding... My candidate plane is a delta wing that uses elevator mixed with aileron on L/R control surfaces at the rear of the wing - 2 servos - plus elevator-only canards forward on a separate single servo. Mixing is currently done in the transmitter but I think that, in order to put a gyro in charge of the pitch, I will have to send pitch (elevator) and roll (ailerons) to the plane separately, send the elevator signal through the gyro, and then use a mixer to combine the pitch gyro output and the aileron channel from the receiver to drive the elevon control surfaces and also 'Y' the output from the gyro to drive the canard.

I would be very interested in seeing a schematic drawing of how you've connected it all up.
Yes, I think you are right in all that. I have not tried a HH gyro but I got to tell ya, this cheap one does everything I need even on a jet this crazy. You just need the gyro to kinda "help out" with what your plane is already doing anyway.... Since the plane is flying around and always moving I'm not sure if a HH gyro would be good, might fight against ya, I don't know. But bottom line for me, is the cheap ones more than did it.

Yes, you nailed the set up for your plane there. Also, I think you can run a Y-connector so you can work both the elevator AND the front canard on pitch. You just might have to turn some servos around or something to make it all work.

I'm real short on time these days but I do plan to do a schematic of my set up when I pull it all apart to install it in the new final plane (which is being built).
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Old Sep 28, 2008, 01:58 PM
"I Did It On Purpose"
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San Diego
Joined Oct 2005
172 Posts
Wow, That high alpha is VERY impressive. Its amazing how those gyros work their magic. Since you are going for a stable High-Alpha platform, have you done any experimenting with Leading edge Slats? Slats are supposed to increased lift at high AoA and also delays stall. Just curious. It would be neat to see a plane with all those features(Slats,flaps,canard,gyros,thrust vectoring).
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Old Sep 28, 2008, 06:32 PM
Just one more flight...
RCSuperPowers's Avatar
Pasadena Cal-i-Forn-I-AY!
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Yes I did try those actually on some of the earlier prototypes. For some reason they didn't seem to help me much at all. The KF airfoil ended up giving me alot more lift, float, and stability at all speeds and angles.
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Old Sep 29, 2008, 08:49 AM
Phlathead
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Roseville, CA
Joined Aug 2006
624 Posts
Great R&D work, Rob! I had a Euro with active canards that was great in high AOA but there was always some minor wing rock after 45 degrees. I might build another and give the gyro approach a try. Subscribed!
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Old Sep 29, 2008, 09:32 AM
Kiss the Sky
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Dorking, Surrey, UK
Joined Jul 2006
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Quote:
Originally Posted by RCSuperPowers
Hey guys, yeah it just takes alot of messin around with it to find what works for whatever you want to do. I can say a few things real quick:

1) If you just want to put 1 gyro on your pitch, roll, or yaw, just plug it in like this:
Receiver ---> Gyro ---> Servo
2) If you have 2 roll servos working together or whatever, just use a y-connector.
3) For elevon/delta mode... I'm not sure how that goes if its mixed from your radio... My simple Dx6 I am using I have it in "regular" mode with no elevon/delta mixing from the radio. I do the mixing from the onboard elevon/delta mixers... I can't remember if thats the only way to do it or not...

I think the gyro gets mad if its AFTER the mixer (either onbaord or radio mixing). If I remember right, the gyro has to go BEFORE the mixer... I think thats one of the reasons why I have to do it with onbaord mixers... its just so much, I honestly don't remember how I wired it all up, but I think thats right. Otherwise the gyro is getting "2 signals" from the mixer and the gyro won't take that.
Radio (no mixing) ---> Gyro ---> onbaord elevon/delta mixer ---> 2 elevon servos

My BIGGEST challenge by far in wiring it all up is cause ch5 does my "canards high alpha" where they face back into the wind and continue to work when the switch is hit, and still be gyro stabilized. And my ch6 when my ailerons flip up as spoilerons and are also still gyro stabilized. This was the hardest part cause I wanted the gyro to correct the roll and pitch on these 2 but NOT the ch5 and ch6 switch they were connected to, if that doesn't make sense.

Dave
Fantastic research and develoment!! - Some basic questions- Would it be possible to use gyros with a 6 channel, 35mhz Futaba radio setup and if fitted to a 'normal' pusher jet with no TV or canards, would it be possible to use Gyros on Elevator and ailrons (or elevons)? Would this make for a very stable model? Is it a 'no go' due to radio limitations and/or the use of a more conventional model pusher jet (either elevator & ailerons or elevons)?
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Old Sep 29, 2008, 10:22 AM
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Canton, Michigan USA
Joined Jul 2007
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I have DX6i and 22" WS KFm2 airfoiled prop-in-the-slot jet that wing rocks quite a bit in high alpha. I have two of the cheapie ESKY gyros that I bought for AP but never used. This is an elevon plane and radio mixes the elevons.

This is a two servo plane. One servo for each elevon. With two servos and two gyros it would be easy to test with two gyros.

I will connect them this way.
Receiver-->gyro-->servo.

I will let you know how it works.

UPDATE: Tried it at lunch (live near work). All I could get was a response to YAW movement. No gyro compensation for pitch or roll. Go figure.
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Old Sep 29, 2008, 12:20 PM
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Sverige, Västra Götalands Län, Trollhättan
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Prof100:
You can't use radio mixing if you are going to have a gyro. The gyro must get a signal that only effects one axis of the plane (either pitch, roll or yaw). With elevon mixing from the radio, the gyro will get a signal which contains both roll and pitch movements and that confuses the gyro since it only works in one axis. For an elevon plane the mixer needs to be after the gyro's.
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Old Sep 29, 2008, 12:45 PM
Just one more flight...
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electriceye
I would say its possible, it will probably take you some time to mess around with it to make it all work, but there is always a way.

kalleman,
Very good explanation. Thats why those little onbaord elevon mixers are needed. Anyone know where to get those? I use to get them from my LHS for like $15 but have not been able to find some online...

Dave
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Old Sep 29, 2008, 01:21 PM
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Canton, Michigan USA
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Quote:
Originally Posted by RCSuperPowers
electriceye
I would say its possible, it will probably take you some time to mess around with it to make it all work, but there is always a way.

kalleman,
Very good explanation. Thats why those little onbaord elevon mixers are needed. Anyone know where to get those? I use to get them from my LHS for like $15 but have not been able to find some online...

Dave
Hobby City has one for $3 but people were posting that it was a bit too "steppy." Here's one from FMAdirect for $19.

http://fmadirect.com/detail.htm?item=1396&section=52

And another from Towerhobbies for $12:
http://www3.towerhobbies.com/cgi-bin...&I=LXELT4&P=ML
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Old Sep 29, 2008, 04:20 PM
Just one more flight...
RCSuperPowers's Avatar
Pasadena Cal-i-Forn-I-AY!
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Yes, good point on the "cheap" gyros. Don't go too cheap as those won't work, I tired that too. I got THIS GYRO HERE
from Nitroplanes. They are just perfect for what I am doing. They have just one simple dial that allows me to adjust how much I want them to move the servo for me, its just perfect.

I know I can find the same gyro for a couple bucks cheaper at other places, but since I am always on a time constriction with the weekly videos and need them in a few days, I'm willing to pay a couple extra bucks to skip the whole "where's my order" jerk around... but thats just me and my luck.

I found with big companies like NitroPlanes as long as I use the "Live Help" feature they have to double check they have them in stock, I get my product every time in a few days.

Dave
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Old Sep 29, 2008, 05:58 PM
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Hi guys I’m new to this forum. I work on rotary wing aircraft (the big ones that carry people) they have a system called SAS (Stability Augmentation System) and if you cut it right down to the bare bones it's essentially exactly what you've created here. Almost all modern jets are inherently unstable and rely heavily on gyros to keep them stable, in fact it would be near impossible to fly a real F-22 or mig-29 without these systems, if you look at their control surfaces when the pilot is doing a simple manoeuvrer they are flicking around at a million miles a second while the pilot is blissfully unaware. I’ve made a depron f-22 and am currently fitting it out with gear and I got to tell ya having a stability system in there will really give me more confidence that i won't turn it into packing foam on it's first flight. Great idea Dave and congrats that Su-35 is awesome
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Old Sep 29, 2008, 06:10 PM
Just one more flight...
RCSuperPowers's Avatar
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Quote:
Originally Posted by Glynn
Hi guys I’m new to this forum. I work on rotary wing aircraft (the big ones that carry people) they have a system called SAS (Stability Augmentation System) and if you cut it right down to the bare bones it's essentially exactly what you've created here. Almost all modern jets are inherently unstable and rely heavily on gyros to keep them stable, in fact it would be near impossible to fly a real F-22 or mig-29 without these systems, if you look at their control surfaces when the pilot is doing a simple manoeuvrer they are flicking around at a million miles a second while the pilot is blissfully unaware. I’ve made a depron f-22 and am currently fitting it out with gear and I got to tell ya having a stability system in there will really give me more confidence that i won't turn it into packing foam on it's first flight. Great idea Dave and congrats that Su-35 is awesome
Oh how cool! Yes, thats how I figured it out, by watching so many videos of the real SU-35 and jets like that. I could see by the way they are moving that their CG must be WAY far back and their was no way the pilot was moving the sick that fast!

Dave
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