FlyinHigh

I have the brushless variety of the UltraFly F-16. My problem is that it won't even come close to balancing without adding a ton of weight in the nose. Is this typical?? And, since the battery is now going to have to be so far forward, so will the ESC. So this means splicing in a wire-run of about 12-14 inches from the ESC to the motor. Does this mean a loss of performance somehow? Is there special low-resistence wire meant for such a purpose??

Any help at all would be appreciated.

AJ1202

I had the same issues with mine, I would not suggest you extend wire from motor to ESC, rather extend the wire from battery to ESC, use larger wire to compensate the longer distance, this will reduce your loss of voltage caused by resistance in the longer wire, extending the wire from the motor will definatly cause you problems. I now have a SU-27 and I have to add 10 oz right in the nose plus the batt to get the CG right. and extended the batt wire by 11 1/2 " to reach the batt bay. Good luck with it

FlyinHigh

Thanks AJ- I will work on it from that end, then. I'm still concerned about the weight....but the UltraFly folks tell me as long as the full-up wieght is 21 oz or less, all is well. I hope I don't have to use 10 of those on nose weight!

By the way, how did yours fly??

AJ1202

FH, It flew like a dream, what I had was a F-15 that I built from download plans, I used a 480 direct drive brushed motor and 3S 1300 lipo, it wouldn't quite hold vertical flight but it was pretty fast and flew great, also I was very surprised and plesaed at how well it would fly at very slow speeds and would just glide to a landing, my AUW was 23 oz I think, on that jet I only had to add 4 or 5 oz for CG. I trashed it finaly but plan to build another one as it was such a good flyer
My SU is the Walkera Flanker and flys real good but struggles as I am running only 1 480 geared motor on it, I am currently converting it to 2 BL motors
It weighs 2 lbs 13oz AUW at present.
Good luck with your F-16, it should fly real good for you

FlyinHigh

Thanks again, AJ. I bought some wire and connectors the other night and put them on the battery to ESC connection. This allows the battery to stay up in the nose as far forward as possible. Then I drilled a couple holes in the nose and stuck some weight in to balance. It now appears close but I'm not sure what the AUW will be. I guess I need to buy a scale of some sort so I can weigh it before flight. I'm excited to see what it will do.

Cptn. Krunch

It might be too late for you but here is what I did...I used some CF rod to stiffen the nose, laid from the base of the wing to the area where the nose cone goes on. I then dug out the foam so I could slide the battery up quite a bit more and reduced the dead weight to 1 oz. Moving your servos foreward helps too. I did change my motor to a small outrunner to further lower the mass. AUW is 15oz with unlimited verticle and I am using an old Poyquest 1800 3 cell. This is one of my favorite flyers. Good luck with yours!

FlyinHigh

Thanks Capt Krunch- you are a little too late, but better than never.....

I ended up sticking 6 oz of weight in the nose with two pencil width lead rods. Still AUW was about 20.5 oz, so I figured it was OK.

So, out to the field I go. After having another electric-savvy flyer check things out, including range check, we tried a launch. Because of the danger of the pusher prop we agreed that he would run, then throw, then I would cut in with the power. All a fine theory, but in practice it ended up with a 90 degree roll to the left followed by a nose dive that broke off some foam. Not at all pretty. So, did you hand launch? Any trick to it? I triple checked the CG, as did my buddy. Control throws were moderate, battery fully charged. Any thoughts??

Thanks for the thoughts.

AJ1202

FH, I know you have to be carefull but I hand launch all my planes at WOT, just make sure your overhand toss allows you to release it and drop your hand out of the way in the same motion, if you torque rolled which is what it sounds like, try half to 3/4 throttle, 20 oz should be fine, I throw mine with just a little up and right trim, this makes the plane lift and counter torque roll at the same time, now be prepared to make trim adj right away but it works for me. Good luck with your next outing, you can do it

Cptn. Krunch

I handlaunch all my jets with a stand - step forward - fling and follow through. From my experience, the best launches by hand are the steady football overhand throw with a follow through to save your piggies. Running just makes the final snap snappier but usually ends up with an uneven pitch. So, to follow through, let your arm keep moving down and away form the plane and back to your sticks. Like golf...be the plane...be the plane....
Good luck

FlyinHigh

So thanks guys for the launching tips. Upon reading them I attempted another launch yesterday with very similar if not identical results as the first. (Roll 90 degrees to the left, nose down and hit the ground hard, about 10 feet in front of the launcher.) I barely have a chance to initiate any control at all. And yes, I did factor in quite a bit of right hand trim with the hope of countering the torque. This was wide open throttle and I managed to get it out of my hand without having the prop "nip" me. (Although frankly guys, my left-handed throws are lame and girl-like...).

So, I have written the folks at UltraFly explaining the situation and asking for help. I get the feeling that I am not developing enough thrust, for whatever reason. Can anyone give me an expected RPM figure for this brushless motor, 3 cell 1500mAh Lipo with a BL8 ESC and factory prop?? Could it be my charger doesn't work right and the battery is not getting a full load? Could it be a "bad" motor that was included in the kit?

Any advice would be appreciated- this is not the "unlimited aerobatic performance" that I was counting on.......it seems as if whatever venture I undertake regarding electric flight continues to end with frustrating results.

AJ1202

FH, this is starting to sound more like thrust angle probs or just not enough air speed to create lift, are you sure you CG is right, does the plane feel strong when holding it and throttling up, will it pull strong in hand, if so your prob OK on thrust power, you may need more up trim, on my SU-27 I have to actually set some up trim on my elevators at neutral otherwise it wont lift at launch I would think you need zero thrust angle or maybe a touch neg. I have mine set at zero, my F-15 had to be about 3 deg, negative, if I put neg in the SU it drives it to the ground unless I use full up elevator. I hope you find the prob soon, I know it can be discuraging

FlyinHigh

Hi AJ- thanks for responding.

The thrust angle is set by the block of wood used as a motor mount and slid into the rear of the fuse as an assembly. The "slot" in the fuse is precut and my assumption was that it is correct. It does have quite a bit of down-angle to it, no doubt. My understanding was that this is part of the design.

As far as noticable thrust, I have been suspicious of this since first throttling up. It didn't seem like that much. It does not "pull" hard on my hand, no. I am going to use my tach to see what kind of RPM that I'm getting. The ESC has an RPM adjustment, or limiter, but that is set at "open". The ESC also has a battery setting for either 2 or 3 cell lipo, which I have adjusted to my battery. The CG is PERFECT. I have spent lots of time on that and am certen of it. As far as up-elevator trim, it's hard to know without flying the thing. The elevator consists of the entire Horz Stab and it's difficult to find neutral based on the angle of the wing or angle of the fuselage. However, I can attest to the fact that there is never enough airspeed to make any of the control surfaces effective.

Great Planes folks wrote back wondering about a "hot smell" or something else identifying a motor malfunction, but I have not noticed anything. If you start at the top of this thread you will note that my first question was about using the battery so far from the motor. Would this have that much of an effect on motor performance (the addtional 12 inches or so of wiring)???? How do I know that the battery is getting a full-up charge??

Cptn. Krunch

Well, from reading the post you have indeed done your research. The only thing I can think of is a reversed prop (on a pusher the lettering should face the front of the jet). You probably knew that, it just was a long shot. If you feel comfoartable doing this, give it a try: Get a tablet scale or a kitchen scale and place the nose on the scale, pay attention to the weight. Carefuly give it full throttle and check the weight again. If you get anything under say, 10-15 oz of thrust, you have a motor/batt issue. Good luck!

FlyinHigh

So, Kapt Krunch- you are a GENIUS! I, on the other hand, am an IDIOT! I read your response yesterday and immediately scoffed at the idea of propeller reversal. I guess, in the back of my mind, I assumed that had I put the prop on backward it would blow thrust FORWARD, hence it was obvious that I was good. But when I checked the lettering, it indeed was on the aft side so I quickly reversed. Upon firing her up she almost flew off my bench! So much for all my troubleshooting and research. I am only admitting to this out of relief that the thing should actually perform to expectations. I thought about dropping out of RC Universe completely and assuming a false identity........

I will let you and AJ know how it flies now that we have these minor details ironed out! Thanks for your help.

Spid

Check your lateral balance too. I had to tape a nickel to the bottom of the right wing tip as mine was tipping to the left when I lifted it up to check my lateral balance. Hand launching WOT, I have a very slight, gradual torque roll to the left. No problems. Flies great. On landing, make sure you release your elevator stick just prior to landing or you risk a good chance of snagging the tip of the elevators and damaging them. Don't ask how I know about that.

Good luck with it!

Cptn. Krunch

Genius, no, but I did stay at a Holiday inn once.....Hey man, you know how I knew....because I have done it too. I betcha she burns holes in the sky now. Glad to help.
Cheers.