Big_Bird

My Feedback: (1)

Ed, it looks like for some reason you need a minimum setting like 30% on the Normal mode for the gyro to act correctly in the AVCS mode. I see no problem with this. It really sounds as if you need to try your ME-109G in the AVCS mode. If I were testing your plane in AVCS mode I would ease on the throttle and come up to about 20 or 25% (somewhat less than lift off speed - fast taxi) on the throttle and watch it respond then drop back to idle. Taxi back in Normal mode and do it again, maybe a little faster this time. Taxi back in Normal mode. If all looked good I would switch back to AVCS and make a normal takeoff taking care not to touch the rudder. I really don't believe it is necessary to instantly switch back to Normal the moment you break ground, just after the plane attains some altitude and before the first turn. That is the way I plan to fly the Jungmeister on it's first AVCS run.

I'll bet that ME-109G is a lot of fun. We go down to Bomber Field in Monaville Texas every September for the B-17 gathering and Big Bird flyin. That is a true Mecca for warbirds. There are usually several Me-109s, FW-190s and Stukas. I lost my Ziroli Corsair down there last year due to radio failure. Here are a few photos.

Thanks, we'll let you guys know the results of the testing.

BarracudaHockey

My Feedback: (11)

90 percent using end points is really 80 percent gain.

Also beware not to touch the rudder trim after the gyro is initialized or it will think you are telling it to turn.

Big_Bird

My Feedback: (1)

"Also beware not to touch the rudder trim after the gyro is initialized or it will think you are telling it to turn. "

Good point.

BarracudaHockey

My Feedback: (11)

Ken those planes are geourgous btw!

Here's my Corsair

Big_Bird

My Feedback: (1)

We are back from the field and the tests went great. The gyro acts exactly like I thought it would. There were no surprises. My friend used his other small Mustang with the gyro mounted on the side of the fuselage instead of the twin Mustang. See photos

The first takeoff was made in Normal with the Normal mode set to 80% and the AVCS mode set to 10%. The plane did a pretty good rudder hands off takeoff but still drifted a little to the left. We had a 5 mph westerly cross wind and we were taking off to the south. A great combo for this type of testing.

The second and third takeoff attempts were made without the gyro in operation (switch in the center position on his 9Z transmitter). In both cases the throttle was shoved hard and the plane did a hard left hook with no manual rudder input. I think he aborted one takeoff and horsed the other one into the air.

He then made a takeoff with AVCS on at 10%. Again the rudder was not touched. The takeoff was fairly straight. The switch was put in Normal after liftoff. After landing I asked him to set the AVCS for 70% and the Normal for 50%. I then made a takeoff in AVCS. Even with the 5 mph cross wind and less than a smooth runway the plane took off arrow straight, as near perfect as you could want. After I landed he took off again in AVCS with the exact same results.

During all of these flights AVCS ,Normal, and off were switched in and out while we observed the resulting reaction. If you are not flying the gyro for 3D aerobatics then I don't think you would want to use it in AVCS other than for takeoff. Takeoff is where AVCS is really worth the money. Of course, during takeoff with AVCS, we didn't touch the rudder and made sure to give the rudder a wiggle and back to neutral before coming up on throttle. In the air when using AVCS, if the rudder were touched the plane would develop a continuous turn in the direction that the rudder had been pushed. To correct this the rudder would have to be moved side to side and back to neutral. Just for normal flying with loops or rolls this is a nuisance. Flying in 50% Normal (rate) is very comfortable and not even noticeable. In fact I couldn't notice any difference between flying in gyro off or Normal.

At no time did we get a scare while using AVCS. So many times I have read DO NOT USE AVCS DURING TAKEOFF. This was obviously written by someone who has never tried AVCS for takeoff, is simply parroting what they read, has a broken gyro, or it is a CYA action. Regardless, they had me fearful but I'm now a true convert after what I saw and experienced today.

BarracudaHockey

My Feedback: (11)

Good stuff, thanks!

I think the real keys are, center the rudder and keep your mits off it during the takeoff sequence.

hlhamner

Big Bird,

Just got back from flying my Twist 40 (GY401 gyro installed) and Showtime 90 (G500A JR rate gyro installed) and I tried the Heading hold mode on the GY401 for take offs and I had similar results. First take off was into about an 8-10 mph wind with throttle slowly and cautiously being fed in until take off. The take off was straight with no surprises. I am running about 80% gain in AVCS (HH) mode. Then, the next takeoff was into a direct cross wind in HH mode and I was ready with the ailerons and the gyro switch. I punched full throttle and again, take off with a direct cross wind was very straight with no surprises. I love taking off with this gyro.

Okay, now for the fun stuff and the real reason I installed the GY401 gyro. Flying about 20 ft above ground in my Twist 40 I switched to 3D rates and then switched from normal gyro mode to heading hold mode and pulled up into a Wall. Apply some power and the little, short moment, Twist, hovered like it was being help by an invisible string from above. The wind was blowing so it looked pretty cool to see it hover 30 ft above ground moving across the field. Torque rolls are now much easier - just need to keep the elevator movements straight and hold some left aileron to help the torque. Again, I love the GY401 for airplanes. I wish I had done this sooner.

I highly recommend the GY401 gyro for use in airplane takeoffs if needed and especially if you are into 3D. I didn't have time to try it but I'll bet this will make waterfalls much easier if the stall is entered in heading hold mode.

The only disadvantage I see so far in using the GY401 gyro is that your dual or triple rates don't work on the gyro channel which, in my case, is the rudder. Everything, even in normal mode, is at the high rate so I used lots of expo, like 75%, on the lo rate switch side. Unless I find the answer for this I would not use the gyro if you have rudder mixed with ailerons to get a coordinated turn on a larger or scale model. It just may give you the opposite of what you expect.

Do you know how to totally disable the GY401 in flight so the dual rates will work as you would expect?


Hank

Big_Bird

My Feedback: (1)

Hank, congratulations on your test today. I have spent a lot of hours combing 4 RC related web sites for answers to "Airplane rudder gyro" questions only to find untruths, half truths, stupid answers and insults. I am hoping that the ground work that we have done here will help some fellow modelers who someday search for the same thing.

As far as how to turn the gyro completely off with a 2 position switch on a Futaba 7 channel radio, I'm not sure. I know my buddy can do it on his 9Z and I may be able to do it on my 8UAPS transmitter because I do have a 3 position switch that I can use. I'll work on that tonight.

Ed, it's now time for you to try the ME-109G on AVCS

Hey cuda, nice Corsair

Big_Bird

My Feedback: (1)

"The only disadvantage I see so far in using the GY401 gyro is that your dual or triple rates don't work on the gyro channel which, in my case, is the rudder. Everything, even in normal mode, is at the high rate so I used lots of expo, like 75%, on the lo rate switch side. Unless I find the answer for this I would not use the gyro if you have rudder mixed with ailerons to get a coordinated turn on a larger or scale model. It just may give you the opposite of what you expect.

Do you know how to totally disable the GY401 in flight so the dual rates will work as you would expect?"

Hank, Maybe I am misunderstanding what you are saying. I drug out my retired Futaba FP-T7UAF transmitter and put a charge on it. I set the dual rate for the rudder channel 4 at 100% and 50%. I wanted to see if the dual rate on channel 4 had anything to do with the operation of the gyro control channel 5. As I suspected, it did not. Channel 4 and 5 are completely separate independent channel and do not effect each other. Even in a situation where the rudder is a mixed slave to the aileron the rudder will receive a normal signal through the gyro. All of this mixed operation should be in the Normal mode and not in the HH mode. At this point I don't see why the dual rate switch on your rudder would not work as it always has.

By the way, with mixing, I can use switch C, a 3 way switch, for AVCS-off-Normal on my 8UAP and 8UAPS transmitters. I don't see any way to do that on your 7UAF

Flyfast1

My Feedback: (1)

Ken and Hank,

I want to thank you both for the work you have done here and the others who have contributed, such as Barracuda. During my searches on the Internet I had found the same warnings as Ken to never use the heading hold mode with an airplane but never found explanations for the warnings. Just conclusory statements that it should never be done. I am glad that those participating in this thread took the time to understand how gyros work and that they can in fact be used safely and effectively in airplanes. Having that P51 as a test bed was perfect. After your experiments and the flight tests by Hank, I feel confident that this is going to work out fine.

"Ed, it's now time for you to try the ME-109G on AVCS" LOL! Yes, I am ready now and will be able to test it next weekend, since it is a long Holiday weekend. Just so you understand my hesitation, I fly off a narrow paved strip with very little room on the sides. On the near side of the runway is a protective barrier that does a good job of protecting pilots from any planes that stray towards the pilot stations, but it will tear up an airplane. Off the far side of the runway is a small grass area that is riddled with gopher and squirrel holes and just beyond that is a barb wire fence that will fillet a plane like a Mackeral. So, takeoffs and landings have to be on the runway.

With the experiments you have run, I feel confident to try this with my ME109G. I am thinking for the first flight that after I taxi and line up with the center line, I will walk out behind the plane to make sure the plane and rudder are aligned with the centerline. I like the idea of setting up the gyro on a three position switch (AVCS mode; off; rate mode) and will program this today on my 9C.

Thanks again,

Ed B.

Big_Bird

My Feedback: (1)

Ed, I think if you were to buy a GY401 and stick it into a plane and only briefly read the instructions then you could get in trouble with AVCS. It is definitely not Plug n Play. If you thoroughly research the characteristics of the gyro and know how to operate it and understand all of the doos and donts then it can be a terrifically good enhancement for your plane. I doubt that it knows that it is in a helicopter or a big ME109G.

Here is a photo of my friends Weddell Williams racer with a G-62 in the nose. It is a super looking and flying plane. Due to the narrow gear it is a great candidate for a 401. Some of the takeoffs can be a bit hairy to say the least. He said he may put one in it also.

I really understand about the confined runways. Most of the fields where I fly are not as confined as yours. Best of luck on your AVCS test next weekend. Let us know how it comes out.

Flyfast1

My Feedback: (1)

I have test results to report sooner than I expected. Encouraged by the reports here and a favorable wind direction, I headed out to the field with a flying buddy. Per the excellent suggestions provided by Ken, I did four taxi tests. The wind was a stiff 17mph, but generally down the runway, sometimes quartering from the left. On each test I taxied out to the runway in rate mode, lined the plane up with the center line and changed to AVCS (HH) mode and reinitialized the position by moving the rudder back and forth. The first few times I did this I walked out to the plane and stood behind it to ensure that the rudder was initialized straight and that the plane was dead center with the center line. On the first run I very gently added throttle and allowed the plane to slowly gain speed, but not to the point of the tail lifting off. The wind was blowing slightly right, causing the plane to weathervane left and I could see the gyro putting in some right rudder to correct. After reducing throttle and letting the plane slow, I switched back to rate mode and taxied back to the starting point. On the second run, I took the plane a little faster, but still not lifting the tail. Same result. On the third run, I went faster and lifted the tail. We could observe the gyro putting in a sigificant amount of right rudder almost immediately to keep the plane lined up on the center line of the runway. AT one point it even put back in a little left rudder to re-correct. So the gyro was working hard and doing a good job of keeping the plane on the center line of the runway. On the four attempt, I went faster still and took the plane off. The result was a very straight takeoff run and climbout, one of the straightest ones I did, and I didn't touch the rudder. I climbed the plane straight out and raised the gear and switch the gyro from AVCS to rate mode, then flew it normal.

So, the 401 gyro in AVCS (HH) mode was able to tame a really squirley 109G. This plane is by far the trickiest plane I have ever had to takeff, and the gyro turned out to be a very important tool in taming this beast. It takes a lot of mental control to resist the temptation to touch the rudder. It was easier during the first few runs because I knew I was going to shutdown the attempt.

Thanks to all the contributions from others. I am glad to answer any questions that others have.

-Ed B.

Big_Bird

My Feedback: (1)

Well there you go Ed. Another unqualified success story. I think the taxi runs are certainly a confidence builder. I hope my 401 comes today.

Do you have the gyro on a 3 position switch so that center is off? What is your AVCS and Normal setting on your transmitter? When flying on Normal, did you notice any difference than before you put the gyro in the plane? What do you have the two pots, delay and limit, on the gyro set on?

I know it's a long trip but if you can ever make it to Bomber Field you and your ME109G will be in good company. This year it is September 14 - 16. We (3 of us from Arlington) always go down Wednesday morning before the meet starts and it will getting crowded at that time. As usual there will be about 200 pilots and 350 planes of which about 70% will be warbirds. I'll be taking the 1/3 scale Jungmeister, 1/3 scale Super Decathlon, and 114" WS PT-19. This year Mack Hodges is supposed to be there with his highly aerobatic B-29 powered by 4 ZDZ80RVs. It's almost unbelievable what he does with that huge airplane. So far I have only seen his performance on DVD. Of course, BB Webber (owner of Bomber Field) will be flying his big Russian Bear Bomber. There will probably be up to 10 10ft WS B-17s. What a GREAT flyin.

hlhamner

Ken,

I fly out of Denton, TX with the North Texas Aeromodelers.

I'd like to visit Bomber Field and compare Gyro notes and look at the great war birds. I ordered another GY401 today for my FuntanaX 50.

Could you furnish me the address, directions or GPS coordinates of Bomber Field? Also, where does the Arlington club fly?

Hank

Big_Bird

My Feedback: (1)

Hi Hank,

I belong to 3 area clubs. Hawk Field Flyers is my home club.
http://www.hawkfield.org/
http://www.gtrcc.org/
http://www.flygsw.org/cgi-bin/yabb2/YaBB.pl

The way we go to Bomber Field is to take IH35W to Waco, and then take State Hwy 6 all the way to Hempstead. Take IH290 east to SH359. Take SH359 south to Monaville (wide spot in the road) and turn west to Bomber Field. Follow the maps below.

I would sure like to see you down there and I guarantee you won't be disappointed. We will have 3 canopies set up and I'll get you a Pit Crew Pass if necessary.

Here is a link to a terriffic gallery by Dick Lee. http://www.pbase.com/dlee/mv2006

Bomber Field link: http://www.bomberfieldusa.com/

See next post for maps.

Big_Bird

My Feedback: (1)

Bomber Field maps.

Flyfast1

My Feedback: (1)

Ken,

Your idea of doing taxi tests was excellent. The strong wind was actually a benefit because the ground speed was lower when the tail lifted, so I had more runway to observe the behavior and watch the gyro adjust for the left pull and wind. The takeoff was really great and straight. My flying buddy even commented that it was a perfect warbird takeoff--dead straight with a gradual climbout. I didn't rush to turn off the gyro, but just waited until I retracted my gear and then hit the gyro switch.

"Do you have the gyro on a 3 position switch so that center is off? What is your AVCS and Normal setting on your transmitter? When flying on Normal, did you notice any difference than before you put the gyro in the plane? What do you have the two pots, delay and limit, on the gyro set on?"

I was going to put it on a three position switch, but decided to go fly at the last minute and didn't have time. So, it stays on a two position switch on the left top of my 9C. In one position the endpoint is set at 90% (AVCS) and 30% in the other position for normal (rate) mode. I am still not sure what gain (or sensitivity) the 90% and 30% endpoint settings correspond to. According to the instructions that came with the 401, 90% of endpoint corresponds to 100% gain, but I don't know if this is a generic instruction that refers to a scale of 0-100%, or would apply to my 9C, where the endpoint range goes from 0 to 140. I can confidently say that the 30% endpoint number for the rate mode appears to have no effect on flying whatsoever. I flew coordinated and non-coordinated turns to see if I could see the rudder doing anything and it didn't appear to. I even did one low and slow flyby and then made a sharp turn away from me with only ailerons and elevator and no rudder input to see if the rudder was doing anything and it didn't appear to move.

Here's my setup for the Futaba GY401 gyro and a Futaba 9252 on rudder:

Digital switch ON
Delay set to 0
Limit set for proper rudder throw, I don't recall exactly, but around 3/4
Endpoints: 90% and 30%

While I was flying, my buddy asked me whether the gyro could be turned back on for landings. Hmm, an interesting thought, but not one I want to try with this plane. But, there is no reason why it would not work to assist in strong cross wind landings. But, the gyro would have to be changed back to AVCS mode on final and rudder wiggled to initialize the heading. Perhaps someone with a sport plane is willing to give it a try?

Ken, Bomber field looks like a fantastic event. I will make it down one of these years. It would be a really long drive from San Francisco in my van with a plane, but it could be quite a journey. Perhaps if I can at least semi-retire one of these years!


-Ed B.

hlhamner

Ed B.

While I haven't turned my GY401 from rate to heading hold mode for landings, I turn HH and normal mode off and on all the time when doing 3D. For example, I almost always take of in rate or normal mode with no gain and, when ready to hover, switch to HH mode and give the rudder a little back and forth to center. Then, I enter the hover and it holds fine. When I decide to end the hover I switch back to normal and I can repeat the process as long as I have fuel. If I need to tweak the rudder while in a hover to point my Twist exactly vertical, I move the rudder while in HH mode and it works fine.

Hank

Flyfast1

My Feedback: (1)

Hank,

That's great. So on final all that would have to be done is to blip the rudder left or right to correct the heading if it was not lined up just right. The only other issue would be for go-arounds, which happen with warbirds. I think in this situation, one would just fly down the runway, slowing adding power, with a slow climbout and then when ready, switch the gyro back to normal mode. One would then go around, line it up on final and turn the gyro back into AVCS mode. Very interesting. This could be very useful in cross wind situations.

-Ed

Big_Bird

My Feedback: (1)

Ed, the main concern that I would have about landing in HH mode would be knowing that I had the hold direction correct. I should be able to see this on final before touch down. An alternative might be to use the rate mode on a higher setting to help with ground looping. According to the 401 instruction sheet 54% indicated on your transmitter is equivalent of 60% gyro gain in either mode. You might want to try 54% or higher indicated on transmitter in the rate mode for ground loop control. As I read it 90% indicated on your transmitter is 100% gyro gain. I'm not sure it would be wise to ever set your transmitter to more than 90% indicated.

It was real easy to set up two mixing functions, on my 8UAPS, using OFS (offset) with channel 6 (flap). I didn't use channel 6 for anything else. Initially I set up AVCS for 70% indicated and rate for 50% indicated. Thanks for the info on delay and limit.

I plan to try HH in loops and Cuban eights. Probably not a good idea for stall turns

Big_Bird

My Feedback: (1)

One more thing to think about with HH in a strong cross wind. You know how your plane will "crab" in a cross wind. I wonder if the rudder will immediately straighten out this crabbed condition as soon as the wheels touch. Just like you would do when using the rudder manually.

Big_Bird

My Feedback: (1)

Hey Guys, IT'S HERE!

I just made an interesting discovery that no one has really said yet. The transmitter has been turned on and the gyro has been initialized in the AVCS mode. You taxi out in the rate mode and line up on the correct heading. You switch to the HH mode and notice that your rudder is centered. You don't have to wiggle the rudder back and forth to set the correct heading. The action of moving the switch from rate to HH sets the new heading. Of course in the air it will not be necessary to wiggle the rudder when you go to AVCS. Hank, next time you go into a hover switch to HH mode from rate without doing the wiggle.

I would like for you guys to verify this, on the ground, for me.

Flyfast1

My Feedback: (1)

Ken,

Mine does not do this. Once I have switched to rate mode, switching back to AVCS mode requirs wiggling the sticks to get it to work correctly. If your's does this, then I may not have mine setup correctly.

-Ed

hlhamner

Big Bird,

If you don't move the rudder left and then right to let the gyro re-center in HH mode for some reason it cuts the gain way down - almost to the point of being worthless.

Try it on the ground and you'll see that when you go back to HH mode without moving the rudder the gyro response to movement is dampened significantly. At least that's the way my GY401 works.

Hank

Big_Bird

My Feedback: (1)

I'm waiting to hear from my friend with the Mustang on the subject. Also waiting to hear from Hank and Jay. Maybe mine is the odd ball. One more thing that I noticed is that I can move the tail to the right about 25 degrees and back to the center three times by hand in AVCS and the rudder will have taken a little offset to the left which means that the new HH direction is a little to the left. In practical terms this probably means little. It is just an observation that the heading can be reset by moving the plane and not the transmitter.

I also notice that there is a little rate action when in HH mode. That is, when the rudder is quickly moved off center by hand the rudder will kick a little and settle with a little rudder cranked in.