Posts: 421
Joined: 5/3/2002 From: Fresno, CA, Status: offline
Put four flights on the Black Magic this morning. Spent most of yesterday getting it ready and nailing down issues that always creep up as the first flight gets close. My father built the plane and while I would check in on it's progress during visits, I hadn't been able to spend much time getting it tuned up. All that was needed to be done was finish up the DEPS and a little minor tweaking and trimming. Plane is covered with Ultracote on the fuse, wings and tail, with painted canopy, cowl and pan.
Plane is powered by a $60 Chinese motor, Jetti 77 ESC, and assorted Chinese packs. All up weight is 11 lbs plus or minus a couple ounces depending one which packs it's flown with. The 4400s put it right at 10 lbs 14-15 ounces, and the 5000s put it probably an ounce or so over. Weight could be further reduced with different servos, but I'm happy with how it feels right now. I have the Futaba brushless 451s on rudder and elevator, and the 9452s on aileron. Has a real good feel. I normally go with 9650s for aileron for electrics, but since weight didn't appear to be a big issue while it was being built, I went for the heavier option. Either would work, but these are sure nice.
Flight Impressions... it flies real nice. I hate to read when somebody says planes fly right off the board with no mix, no adjustments. While that's not the case with this one, it's pretty close. You could fly it as is and be okay, but I know that with more time on the plane, issues will creep up.
CG is right where Mike Hester called for, and for right now I like it. It snaps well, upright spin is nice, inverted spin does not break... I think I need more down elevator. Uplines are straighter than my Genesis ever was, just locks in going up, no pushing or pulling so far. On the downline it pulls to the canopy slightly. Can be mixed out, but right now I'll leave it until I'm comfortable with the CG and incidences.
The first flight I had the 20x13 prop and it felt good, however with the speed that I flew it at, it pushed to the wheels in knife edge both directions. This was slight though, and only noticed on extended KE. Four points, eight points and slow rolls hid this tendency for the most part.
Once I put the 20.5x14 prop on and flew a little faster, it pushed less. I feel it will still need a mix, but it will be slight. Like I said, it will fly fine the way it is, but the mixing will lock it in. The speed and pull with the 20.5x14 was very nice and verticals were with authority and maybe 70-75% throttle. A good, quick, solid horizontal speed was with 50%.
Rudder was touchy around neutral, some fiddling with the radio will iron that out. I have a lot of expo in already, I think just a touch more will help this. I did have some issues with the plane locking in on square corners, pushing and pulling. Not sure to what extent I'm having a trim issue or not, need more time. But with doing consecutive inside and outside loops towards myself I found that with minimal and smooth rudder correction, and leaving the wings alone, it was very predictable and solid. I am very rusty, so I know alot of the issues likely have to do with the idiot on the sticks. I was impressed with the locked on feel of the plane and found that in most arenas that if I had the wings level to begin with, and didn't twiddle the sticks unnecessarily (duh!), the plane performed as expected.
Like I said, I flew four flights... the last flight was cut short. I put in the 5000 packs and I did notice that I lacked the power of the previous flights, but it was a new battery and sometimes they need to 'break in'. Because of that, the first couple of flights with a new battery are kept to less than five minutes. At about 4:30 I pulled into a vertical and lost power, it just fell out of it! Chopped the throttle and brought it around to a normal landing.
Upon opening the plane up, one of the batteries was significantly puffed and distorted, it looked like a chunk of play doh formed by a five year old. I ripped off the pack and cut it loose. The pic is attached... after one flight the pack blew open and the pic can be seen below. There is a warranty on these packs, and we have had good luck returning items in the past, I'll let you know on what they do about it. Obviously I can't return the pack, it's too dangerous. We stood around and stared at it for a while, the glow purists at the field had a good time at my expense! [)]
Overall... nice, smooth, solid plane. Very honest as advertised. No plane is perfect, and neither is this one for sure, but it is much more solid than my Genesis (which by the way is flying better than it ever has right now) and reminds me of my old Pinnacle. I don't have nearly enough time on it to say much more, but right now I like it, should be a lot of fun.
Tom M
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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater
Posts: 421
Joined: 5/3/2002 From: Fresno, CA, Status: offline
Steve,
I am secure enough in my masculinity to admit that I cried after I sold you that Pinnacle... it was a VERY nice flying plane that I couldn't justify keeping. I'm glad it went to a good home, hopefully I can hook up with you at a contest to visit (the plane [)])
I can't say that it flys as well as the Pinnacle just yet, but it does remind me of it so far.
Tom
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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater
Posts: 1059
Joined: 1/15/2002 From: Hoffman Estates,
IL, USA Status: offline
Tom if I were you I would look at the amount of amps the Chinese motor is pulling. Chris Moon and I had the bigger Hextronic motor last year and it pulled big amps. He had it running on a smaller prop. I'm not saying for sure but it seems very odd to do that to a new pack. That's one of the beauty's of the Dualsky 12T motors. They pull pretty low amps and are easier on the lipo's. Hope you get it figured out without too much damage. Your new plane looks beautiful. Mike
Posts: 2308
Joined: 10/27/2002 From: Woodstock, GA, USA Status: offline
Hi Tom, looks fantastic!
I just spent several emails with George Miller grilling him on trimming this thing, and his experience was very similar to yours, and mine, and pretty much everyone else's with an electric Black Magic. Everything you describe is a symptom of set up and can be tweaked to darned near perfection.
As I told him, you may wish to push the CG a little forward and add a bit of positive incidence to the wing. if it's pulling to the canopy in a downline after that, you may want to decrease the down thrust slightly, just keep an eye on your uplines. When the thrust is perfect both are dead clean. Now I am talking about splitting hairs, but this plane can be gotten down to pretty much minimal to zero mix. in the end you should end up with maybe a percent or 2 up elevator to left rudder, and zero to about a percent with right. you may or may not end up with about 1-2% of downline mix, but I hate that mix because it can bite you throughout the flight if it's more than say 1.5%. With a little diligent trimming you can get rid of it and not pick up any somewhere else. but if you end up with a hair bit of elevator to rudder, that's pretty normal and won't bite you elsewhere.
When you "nail" the set up (and you absolutely did right by the 20x15 range prop) you will KNOW it. Mixes will pretty much zero out and it will be as close to perfect as a plane gets. What you're feeling with the rudder and the corners is something that messed with me for a long time....it doesn't tend to "walk" so you have to pull clean. Since the rudder is pretty touchy you have to learn to lock the wings level and trust that it will pull clean....because it will. Also in slow rolls, you have to leave the rudder alone for a longer period or you'll climb out.
One thing: as you're trimming, watch for any roll coupling or aileron differential. This plane has NONE of either when it's within limits, so if any creeps up, you'll know you went too far with something. But this plane is worth spending the time to trim.
This plane is different....but wait until you get it trimmed to your liking, then fly in a nasty wind THEN you'll see where this plane really shines.
You will find that you need the power and penetration on this beastie, and that might be where that new pack possibly got pushed a bit....I'm just guessing?
Anyway gotta go to a contest this weekend so have fun and congrats, I hope you enjoy it!
-Mike
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Joined: 5/17/2003 From: Lake Charles,
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HI Tom,
I've got about 25 flights on my BMV3 now and I must say it flies better than the E Pinnacle I bought from you last year. I'm using the Dualsky 12T and I have been flying a 20X13 prop. I've played with the trim on mine and have it very close to "Perfect" for me. the last couple of flights I had on it it really locked on like rails....I'll be flying it this weekend and taking the Pinnacle as a backup.
As Mike says, I've decreased downthrust, added right thrust, tweaked the wing incidence and moved the CG forward slightly to get where I am, but I have very little rudder mixing (2-3% up elevator with left rudder only) and no appreciable roll with rudder. It will go up forever with 75% throttle and cruises much faster than my Pinnacle at 1/2 throttle. Even though it is BIG, I find it faster than the Pinnacle, and I'm using less amperage for a pattern (though different motor and batt packs so can't say for sure)
Posts: 421
Joined: 5/3/2002 From: Fresno, CA, Status: offline
The motor pulled about 73 amps with the prop we used. This issue with the battery turned up on the last flight, where the first two were with HXT 4100s, third flight was a Zippy 4400 (first flight as well). I don't think excess current was the issue... perhaps excess current with THAT BATTERY with THAT (unknown at this time) DEFECT, but all other batteries worked fine. I have used dozens of Lipos in this application (used to be a dealer for a name brand) and have never experienced this EVEN WHEN I did exceed the limitations of the pack. Typically you will lose power, but the battery will puff slightly and or/get soft and very warm. This just blew up. Also my experience as a former dealer tells me that while this is rare, it does happen with some defects. I had something similar, though much less fantastic, with a name brand... you could see the paste through the wrapping. That was a result of a small batch that had a defect in manufacture. At this time I really that this was simply a defective pack. This set up is not 'proven' per se, so there could be a gremlin in there somewhere, but it demonstrated earlier that day that worked well. The 5000s showed from take off that something was wrong... I didn't know how wrong until the end of the flight.
Like I have said before, using this cheap stuff is not for the faint of heart (or perhaps even for the smart folks). You are going to go through batteries, motors, etc... while you figure out what works (if anything). Unfortunately one such issue happened on the first flight. Of course, all of this can change as I'm going out to fly it again and might find out that I'm an idiot and am for some reason pulling too many amps (probably because I'm using a cheap motor [)]) The other thing is, Dad and some of the guys at his field have used this combo (even with a generic ESC) quite a bit without incident. We'll see how today goes. Truth is the only reason I am using this stuff is that I simply cannot afford the 'good stuff'. It was either this, or nothing. Even if another pack fails, I am still way ahead as far as money i have paid.
Mike, your trimming comments are interesting and i will have to start paying real close attention when I fly it later today. It actually looks like I am pretty close to what you say is the 'ideal'. The rudder mixing is very slight, and I think that the elevator to throttle is VERY slight... probably around 1-2%. But I, like you, hate that mix, it has never worked for me and causes more problems for me than it usually solves. But that's just personal preference.
Good to know that I don't have any odd issues with the trimming, I'll see how it goes today... which really, and sadly, is probably the last time I'll get to fly it for a month or two due to work. But I'll take what I can get.
Tom M
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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater
Posts: 2308
Joined: 10/27/2002 From: Woodstock, GA, USA Status: offline
Don't get me wrong, you can get this plane to darn near zero mix, if not dead zero, with enough work. but after a point it becomes a diminishing returns sort of thing. Takes more work to get the smallest result. Hebert would say the same thing. Difference is, at some point to me personally I just don't think it's worth the time and effort to try and get rid of 1-2% mix.
After re-test flying my prototype last weekend (rebuilt for the second time) I just checked and I have 1% up E to L rudder, that's it. I had a slight pull to the canopy in a downline and fixed that with a tweak of positive on the stab, which was small enough to not effect the KE mix. The CG on this plane is a little farther forward than I was running in the past. It carries right at .5+ on the wing and just a hair positive on the stab, and seems to like it best there.
But originally, I lost the snap....and had to go in and change the throws. it works WELL, but it's different than the snap settings on most other planes. Tons of aileron, not much rudder at all, and a moderate amount of elevator, just enough to get a break. And it's a for real snap, not a twinkle. Doesn't displace much if any.
I'm glad you guys are doing this at the same time as me testing a new one, because it forces me to rethink, double check, and pay more attention. Right now I'm LOVING the way mine is flying. Flies just like the red plane I flew at the nats last year. Which is, pretty darned amazing. And about a pound lighter LOL
-Mike
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Team Cool Power, YS Parts and Services, Mercury Adhesives, Dragonfire Customs, owner Custom Airframes of America
Posts: 2308
Joined: 10/27/2002 From: Woodstock, GA, USA Status: offline
Oh and FWIW, we ran the HXT motor last year with no issues. It has darned near the same numbers as the AXI, but was actually a little cooler and smoother. Pulled 2 more amps, 100 less RPMs, and 100 more watts. Whoopedy doo. Close enough.
Packs and speed controls, well I am not sure they are "there" yet. but motors? Yep, that one is pretty sweet. It likes the 20x15 BTW.....
-Mike
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Posts: 169
Joined: 1/16/2003 From: Griffin,
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Like Mike said, the HXT that I had in the BM V2 was nearly identical to the AXI in stats. It seems to be a very good motor and the price makes it a no brainer for me to try. Mike and I always had the question in the back of our minds as to how long it would last. I kept waiting for it to self destruct, but it never did. Unfortunately I planted the plane in the ground a few months ago, but I did fly the HXT for at least 6 months with very good results.
I have another cheapie to try soon and if the bench runs look good, I will put in on a V3. It should spin props similar in size and around the same RPM as a DZ. We shall see how it works.
Emory
< Message edited by patternflyr -- 5/8/2008 3:34:09 PM >
Posts: 421
Joined: 5/3/2002 From: Fresno, CA, Status: offline
I have 12 flights on the plane as of today. Today was actually the first day I had flown it at sea level, the first couple days were flown at about 5000', and you can see quite a bit of difference. Prop choices change, control response is different, speeds are different... anyway, I was curious to see how the motor flew at low altitude and about 80 degrees.
The 20x13 prop is a good choice on this motor and this plane at this altitude. Has a nice overall feel, similar to the 20.5x14 felt at 5000'. Which is about right as I normally go up in pitch as the field elevation rises. Played with mixing and CG... I settled on 1.5% up el. with left rudder, and 1% with right rudder. Seems slight, but I could tell the difference with the mixing on and off.
Not to sound like a broken record, but again, the plane felt very locked in and solid. The last couple flights were spent getting the throws and expo the way I like them. Had I the time to practice and be proficient with the pattern, I could fly it in a contest tomorrow and feel confident. In the plane... not my flying .
So far I'm totally pleased with the motor. It could blow up tomorrow, but right now it has plenty of power and runs very smooth. Sixty bucks shipped to my door aint bad either.
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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater
Posts: 421
Joined: 5/3/2002 From: Fresno, CA, Status: offline
I have heard back from Hobby City regarding the battery as shown above, they will return it if I send it back to them. I do not feel it safe to do so, and have informed them of that, so i guess I am out of luck. I do understand their position, but it's still a bitter pill. One piece of advice if you are purchasing batteries from Hobby City, you should review their return policies regarding batteries. They are restrictive and pretty specific. Though it wouldn't have helped me in this issue, if I do buy batteries from there in the future, I will go about things differently. Having said that, I figure I am still ahead of the game cost wise, but should I suffer another such incident, I might have to save my pennies and buy something from a local dealer.
I have a couple of cycles with the 4400s now, and all is well so far.
T
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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater
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Another Black Magic Maiden - 
THEN you'll see where this plane really shines. 
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