rcpattern

My Feedback: (45)

Dana,

In my experience the plane hunted with the C/G aft. It had a VERY slow speed window with which it was happy. Moving the C/G forward made the plane much more stable at a wider speed range. I can still do a knife edge loop on low rates, so I don't think it has affected rudder authority. I know Andrew ran his C/G fairly far forward as well with no issues. I have no idea how Mr. Park flies the plane as tail heavy as he likes, unless he flies VERY slow. Even then, I just didn't like how it felt. I was slowly sneaking up on it, but just wasn't completely happy, and then about 2 weeks ago, I moved my packs over 1" forward on a flight, just to see what happened and I really liked the result. Even a few others who were watching said the plane looked much more locked. I think let several people fly my plane that had flown the original one Chris Moon had with the aft C/G and they all agreed it was a totally different plane.

Arch

Dave Harmon

Tony, Mike Arch....anyone....in addition to the things you have all mentioned....have any of you found that you needed to move the rudder servo forward to the usual place to make c/g?
I suspect that you all are moving the battery plate forward but I have to ask.
Also....I noticed a comment or two about the rudder servo installation regarding fuse side flex.
Has this been an issue serious enough to fix?
I'm at a decision point right now and even though I was skeptical of the c/g location and a couple of other things...I always like to give the mfgr a chance by building to his spec.

danamania

Mr. Park's notes did say that he likes to fly slow, LOL! I'm glad to hear that the rudder remains effective so that just leaves CG vs. incidence, which is, I guess, as it should be. AJ's CG was 275 and I assume that was with the stock incidence, does anyone recall? Anyway, will probably start 270-275 since that is what works and worry about increasing incidence once we have some more data. Thanks for sharing Arch, much appreciated!

rcpattern

My Feedback: (45)

Dave,

You are correct. All I have done is move the batteries forward. My rudder is in the tail. I didn't like how he did his mounts, so I made my own, but haven't had any issues with the fuse flexing. At least nothing that is noticeable in flight.

Arch

shannah

My Feedback: (5)

Dana
You will probably be very happy with the results if you go with CG in the 270-275mm range and stock incidence on wings and stabs. That is essentially where I fly mine and I am very satisfied with the result. I think it locks in very well and I don't fly ultra slow. I do keep my overall speed down however.

TonyF

My Feedback: (92)

Mr. Park has asked me to rewrite his discussions on the Nuance and the Prolog that he has on his website. I have started but the translation leaves a lot to be desired and I am trying to make sure the understanding is passed correctly. I am also going to add in my experience with the Nuance.

Yesterday I painted the LG legs and the wheel pants red. I used a Rustoleum spray can that is pretty close to the red that is on my plane. Hard to say if that was the difference or if it was just a better day for seeing, but I had less trouble following the plane on the one flight I got in. Also, before I flew I checked where I have the CG. With the canopy off, the model balanced about 1/8" aft of the center of the wing tube. I have no problem with rudder authority. I have a "Normal" mode that I fly all my rolling maneuvers with, the horizontal rolls, rolling circles and the knife-edge loops. It moves the rudder very little and I have more then enough for the loops. The only thing the plane is not doing yet to my satisfaction is the reversing spins in P. But I think with more work on throws and technique that will come around. No reason it won't.

I mounted the rudder servo exactly as he shows it with exactly the same technique. I really like it over a forward location and cables. Much simpler. I've had problems with cables slipping over the years and this isn't going to do that. But I also used 5 pin type hinges on the rudder instead of the CA hinges. Partly because of using a pushrod instead of cables and partly because I can then use a long wire to engage all the hinges and be able to remove the rudder for shipping. I had no problem getting the CG but you have to mount the battery try over the LG mount, not behind it. I made a few small changes to the stock tray to get this mounted securely in to the fuse. This must be mounted well or you're risking a battery ejection.

Mike, I went to the eye doctor last year. She told me then my left eye is starting to develop a cataract. It's not developed enough for removal surgery so I'm going to have to live with it for a while. Does make things really tough at times. It sucks getting old!

In my opinion the airplane tracks in yaw beautifully. So far I have seen no reason to add anything even with the Contra. My problem in tracking is only a visual problem and only when down low running in to center. It may take a color scheme change to get fully confident with my visual of the model. Or maybe a new pair of eyes!

TonyF

My Feedback: (92)

One more thing. I have no idea what my incidence is, I never measure it. I started with where the stock incidence was, it needed roll trim and up elevator trim on the first flight. I had installed wing adjusters so I started adding incidence to the wing that needed it to center the roll trim and to reduce the up elevator trim. I kept adjusting until the ailerons were centered.

I guess I could measure it, but to what? The canopy line? What would be the reference?

shannah

My Feedback: (5)

Here's a pic showing my battery tray location. It is over the LG mount. The TP 4400 25C pack is centered on the LG mount. Heavier packs (1160gm Sky Lipo's) are about 1/2" from the rear of the tray. I'll see if I have a better pic of where the tray is on mine.
http://www.rcuniverse.com/forum/m_10..._3/key_/tm.htm

Dave Harmon

Arch, Tony and Steve.....thanks for the quick comments....I appreciate the help!

danamania

Thanks Steve, this is exactly the kind of confirmation that I need to feel good about completing the build as simply as possible. This has been a most helpful thread from the beginning! Dana

danamania

Thanks for your posts Tony! I too am doing the detachable, hinged rudder (so it fits in the car). Very helpful to read how you used the adjusters to tweak rather than go for an absolute number.  This makes me feel like it's ok to just go stock and see how she flies first.  Cheers!  Dana

jonlowe

My Feedback: (12)

Tony,
I had cataract surgery on my first eye in 2005, and my second eye last year. I told the doctor that it was affecting my ability to pursue my hobby, and that I needed excellent sight at 150 meters. He used that info to tell the insurance company that I needed cataract surgery sooner than later because it was affecting my ability to do things.

My first surgery was on an eye that was so near sighted that I had around 20/400 vision uncorrected. Probably a congenital thing. The lens inplant corrected it to around 20/30 or so, which the doctor said was a home run because I started off so bad. It was easily corrected to 20/20. The second eye really improved my flying. I also find that I have to use much darker sunglasses than I used to. I find that Model Glasses prescription sunglasses work well. Besides the tints that come with Model Glasses, I use a greenish/yellow mirrored tint that is available from their golf line of lenses. Different tints in different light conditions make a big difference for me.

My normal glasses are progressives, but my Model Glasses are bifocals, because I find they give me a much larger area of in focus vision than the progresses for flying.

After the first surgery, I flew the next day. Only have to wear a protective cover at night. It is well worth it.

Following this thread closely as I just got my Nuance flying. Moving the cg forward is helping me also.

mups53

My Feedback: (41)

Jon, Tony I don't have a cataract problem yet but I'm sure it'll happen. I think my problem was a prescription change that messed up my idea of space. I did get a pair of Phil's Modelglasses. I'm awaiting my 3rd set of lenses. So far it's been a disaster. God I reallyhate this stuff.
This thread is really helpful. I may experiment with the CG but anything more forward than what I have will not allow me to taxi on a grass field without a gear change.
I'll be testing a Prolog in a week. That should be interesting. Mike

pippy

Hi all, getting old is a bummer especially for the sport we do. I bought a pair of sport spex with changeable color lenses that also flip up when I want to look at the radio or in the model. They also have separate plug in prescription lenses which my optician set for flying at 150m. They work really well for golf also as I can't hit a ball much further than that.
For very bright days I use grey mirror lenses, for bright but not very sunny I use smoke grey, for evening when the sun is going down I use rose tint and for dark overcast days I have amber lenses. It sounds like a lot of work but it is worthwhile.

MTK

A suggestion if I may on using standard foam wheels. If the pant is wide enough in its midsection to accept the width of the wheel hub, but the pant bottom is too narrow, try sanding the wheels a bit. This is fairly simple if you have a hand drill and some 60 grit paper. If you can't force the wheel hub through the pant opening, you may need to sand the hub a little....

MTK

Tony,

Suggestion....If you have a height gauge, establish zero of the stab. Then measuere the difference in heights of LE and TE on your wing and calculate the AOA. While you are at it, take a look at your downthrust too, with stab at zero.

Or shoot a lazer line on the side of the stab and zero the stab accordingly. Then take a look at the wing....

TonyF

My Feedback: (92)

Or, I could just fly the thing. I'm not that interested in what the exact number is but how it flies. That probably doesn't help others who ask me what the numbers should be, but it works for me. Maybe when I get it to a point where I'm pretty happy with it I might measure just to give BJ Craft some good info. But I don't really need to know to make me happy.

shannah

My Feedback: (5)

I tried a few different CG locations this afternoon and I have to say that I strongly prefer my 270mm location. I moved it forward about 0.5" and again 0.75" and I just don't feel that it benefits from this. In fact, I think it causes the tail to be less stable and I noticed it skidding a bit. I re-read his design notes and I think everyone should do that. I experience pretty much what he is describing. As a note, the 270mm location is measured from the back corner of the canopy mount. That puts the CG right between the wing bolt and rear of the wing tube. To me, it was much better at rolling and overall tracking at this location. With a more forward CG I had the feeling that the nose was leading the plane and the tail was not as predictable. It was a bit windy but I think my results would be the same no matter what. Toss all that out when you go with a contra drive because I think that setup needs a forward CG no matter what.

To check the CG location I simply picked the airplane up, without canopy mounted, and lifted it with my thumb and forefinger grabbing the fuse right along the canopy mount line and found the balance point. I noticed that BJ did this before each flight to make sure the battery was in the right location.

In the end I guess it really comes down to personal preference. For me, 270mm from the back of the canopy feels great. I fly it at a moderate pace and use a lot of throttle control. So, experiment a bit but keep in mind the overall design of the airframe and try to stay in the sweet spot. You'll know when you hit it.

danamania

My build is far enough along that I could do a trial balance with packs in.  Very happy to get 270 where I placed the battery tray. Thanks to all who posted pix or text about pack & tray location, very helpful.  That's where I will start and I do have room on the tray to move fwd & aft to fine tune CG.  The next decision will be to leave the preset incidence or to go for 0.5" and adjusters. Will definitely fly as is first to see how the design feels to me, but have healthy respect to the flyers who converted to the time-honored incidence setting.  At my Sportsman skill level, will be interesting to see if I can discern the difference LOL!  BTW, the replacement gear is not in yet so I balanced with the stock legs and so I could get it off the stand onto the bench.  Will fly it with larger wheels and no pants at first due to the thick grass at most of the sites I fly.  Will post pix when the Tru-Turn spinner arrives , due early next week.  Off to Pocono pattern today, wish me luck!

rgreen24

My Feedback: (6)

Arch, and Tony with your forward CG are you carrying up trim on your elevator or is it neutral?

shannah

My Feedback: (5)

I did a measurement check on where my CG is relative to the TE of the wing root. I am approx 275mm from the TE of the wing root and 270mm from the back on the canopy mount. So, that distance being quoted for CG location will depend on how you measure. I haven't taken the time to find the MAC and calculate my CG location.

I asked B.J. a few questions about CG placement and he also said that a key factor is your servo choice. If you are using something like a BLS153 with a 6v speed of 0.12 or a 9650 with a speed of 0.11 then you may want to move the CG to the front. That is where I ended up with my 9650, basically 275mm from the TE (270mm from the back of the canopy mount). This has to do with servo speed.

I am attaching a couple pics of where mine is and also a pic from the build guide. His design notes recommend a 260mm start and +10 -20(?)mm. For me, 260mm is too far back. I think you would be unhappy if you were at 240mm for sure. I am at the forward edge of what he recommends (the pencil line on the canopy deck is my CG location). But, as always, "your mileage may vary" and it really comes down to your personal preference.

Here's a link to the design notes: http://rcone.kr/board/index.html?id=bjreference1&no=14

Download the doc file if you have ms Word. It is good insight into what he had in mind and how he set it up.

ematech

Hi all, Here is my 2 cents worth. I have set up my Nuance as per the instructions, without wing adjusters, without measuring any incidences. After reviewing the web sites and seeing how each airplane is positioned on a jig to produce the holes for the wing/stab I do not think that anyone could build a more consistent airplane. My airplane required one click of right aileron trim and one click of elevator trim and nothing for the rudder. I aligned the motor against the fuse. I am mixing 2% downline mix NO OTHER MIX required!This is truthfully the first airplane that I did not anally check every measurement. As Steve suggested to me just put it together and fly. As a note this is also the first pattern airplane that the recommended throws and set-up were “right on” for my feel. Most of the setups are just to hot. My balance point is 265 from the rear canopy seam. I am running a Hacker Q80, 20.5/14 prop, Sky lipo 4400, Hyperion ds20-smd servos, Airtronics radio. I slowed down the rudder servo to .19sec to stop a small tail wag. I burn 3700mAh in 7 min, which is about 4 maneuvers more than the advanced pattern .My airplane is winning in the advanced class... 4 contests in 5 weeks! Heading to the NATS in July
John

shannah

My Feedback: (5)

Hey John,
That's great to hear. I knew you would like the Nuance.

Good luck at the Nats!!

I'll see you at some D7 events later this season.

By the way, it is interesting that you slowed down the Rudder servo to .19 sec. BJ keeps talking about that and he made reference to it in his design notes. I didn't feel the need for it but I see what it is accomplishing, especially with the aft CG. He also says that elevator servo speed is important to watch. Faster elevator servos will require moving the CG slightly forward.

danamania

Maiden day.  Squeezed in one quick turn around the onion patch (cornfield actually) between a thundershower and the arrival of the mower and gusty cold front.  Quartering crosswinds 5-7.  The goal was to see how ground handling was with the stock legs and 3" foam wheels sans pants in the thick, damp grass.  First of all, I was delighted with the ground clearance of appx. 4.5" from the tip of the Falcon 20.5x14.5 to the floor. With a little up elevator & left stick finesse, this test was passed. Takeoff was uneventful, but I was on the rudder and elevator much more than with the Osiris or 2m Vanquish as she yawed into the wind.  Lift off was somewhere between 50-60% throttle to the Advance (straight line, no throttle curve set; med start, med timing, 8 kHz on the Ice2 80HV).  The maiden CG was about 275 which I found to be a bit nose heavy feeling in the landing pattern with a quick downwind roll for fun; she took a bit of nose up trim (will try 270 on the next flight).  Also took some aileron trim so I need to look into that on a calmer day.  The air was not so smooth so no aerobatics or trim passes: made one low pass to get the feel of the glide and one full stop landing which was very pleasant.

astropuppy

My Feedback: (23)

Go get them John!