dlian

Guys, I'm a newbie to RC choppers and am hoping for some advice about trimming my HF properly. My questions are:

1. When properly trimmed, should the HF be able to hover hands-off out of ground effect?
2. When trying to hover at about 1ft in ground effect, the HF has anti-clockwise pendulum rotation while drifting left (ie left spiral). Despite having maximum right yaw trim and a touch of right roll and forward pitch trims, it still continues to do a left spiral. Is my trim wrong?
3. When hovering at about 4-5ft, the spiral is very minimal but there's still a little left yaw. With the yaw trim set a maximum right, what should I do to remove the remaining left yaw?
4. I've shortened the upper blade link as much as it will go but there's still a small tracking error of about 2-3mm at the tip. What's going on here?

Thanks in advance for your help!

humveecrusher

Kas...I believe that is a sign that the battery is to low. These batteries are tricky. We need to be careful not to drain them down to much between charges or it will damage them. The heli will shut down if the battery is to low. It is a safety feature. It sucks when it does it when you are up to high. If you see that the power is getting low set her down and try again. If it is still low on power, time for a charge. If they get to hot it can cause damage too. I'm having a hard time trying to figure out the balance of them being to low or to hot. Hope this helps.

humveecrusher

Hi dlian, I hope that I can be some help. Most of this is trying and learning.


1. Yes. It will hover for short times hands off.

2. Check and make sure that the stabilizer bar is balanced...that the ends are the same distance from the center. Make sure that blades are balanced as close as possible. Make sure that the blades are tracking as close as possible. If the link is turned all the in try turning it out 180 degrees at a time and see if it gets better. I have found that the pendulum hover is caused by one or more of these things.

3. If the tracking is correct the blades will have the proper pitch. With proper pitch you should be able to hover close to neutral trim and have plenty of trim left if you need it.

4. Like I said previously, try turning the link out 180 degrees at a time and see if that helps. I have found that if the blades are balanced they will track better.

Hope this helps.

dlian

Thanks for your tips HV!

I noticed that although the stabiliser weights are set at equal distances from the mast, one bar always drops lower than the other when the rotor is at rest. Is this normal or should the stabiliser be balanced even at rest?

humveecrusher

It should balance, but make sure that the linkage rocks back and forth loosely and turn the link ends so they are 40 - 50 degrees from each other. I keep my top blades pretty loose so sometimes the bar will fall to one side or the other just because the blade pulls it from being loose and moving while sitting. Is this what you are experiencing? If not, move the heavy side in a little bit to balance it out.

dlian

After I posted my message, I realised that the drop was caused by one blade being slightly folded. Doh!

humveecrusher

LOL! That's the way it goes....observe and learn.

ToyFigure

Hi guys, just received my Dragonfly yesterday and was reading the manual but nowhere did it mention how to charge the battery, which is a 840mah li-poly.

How long should I charge it for because I've read in other threads that these li-ployers can cause some serious damage (i.e. fire or explosion) if not charged properly.

Thanks for all your help.

PS can't wait to fly my new heli!

Kasowitz

Hi, You should have a Green and a Red light on your Charger. When you first plug in your charger (not hooked up to the battery) you should see both lights light up. Once you attach the battery to the charger cable the Red light should go out, this means its charging. When the charging is finnished the Red light will come back on, at that time you can disconnect the battery from the charger. I hope this helps ! I have a HouseFly, so hopefully its the same kind of charging system, I believe it is though. Let me know if you have any other questions about it.

ToyFigure

My Dragonfly is exactly the same as the Housefly except for the Li-Po charger. It's just a regular black charger whith no lights[&o]

So how long should I charge the battery? 1 1/2 hours?

I also bought an extra 3-cell li-po battery with charger from e-bay and guess what? The charge that came with it was for Li-Ion batteries (again no lights) but have a sticker stating charge time is 1.5 hrs. Does Li-Ion chargers work with Li-Po batteries?

Please help.[]

Kasowitz

Hmmm, Im not sure ! I would be afraid to just estimate how long to leave it hooked up. I have read some bad horror stories about Li-Po batteries exploding because they werent being charged correctly or were overcharged. If I was in your situation I would look for a Li-Po charger online that has a charge cut-off (that will stop charging the battery automatically when charge is complete). I would'nt try and estimate charge times, that seems risky to me. But who knows maybe someone else will have a better answer ! Dont mean to scare you at all, but you should know the risks of over charging

humveecrusher

Estimated charge time is about an hour. If it is the same battery as the House-Fly then it has a circuit in the battery to prevent overcharging.

warren52nz

Hi Guys

Just finished reading this whole thread and thought I'd jump in. I have two of these XRB "Dragonfly" choppers and have pretty much sorted out what's going on with them, I think. I take it humveecrusher is Joe from Ohio with whom I've had quite a few emails lately.
?
Anyway, here's what I've found:

If the model is yawing (slowly) left or right, it's caused by the upper and lower blades having a different amount of drag. There is a version of these things that has adjustments for the pitch of the upper blades to correct this. I have one of each. I make my own blades so I can adjust the pitch during the moulding process.

You may not want to do this but you could adjust the yaw by shortening the upper or lower blades. Shortening the lower blades will cause yaw to the right and the uppers to the left. It will reduce the lift a bit but should work OK. When you make your own blades this is no problem at all.

Mine tended to yaw at full trim too so I opened the transmitter, and re-mounted the yaw potentiometer by drilling a new hole so that it operated in a different part of the range. That's a bit of surgery and shouldn't be done if you're not very handy. But my yaw control is in the middle now when it's trimmed. 8^)

If it starts spinning really fast, it can be one of several things:

1. You're holding it in your hand and the gyro (it has a yaw gyro) is going berserk trying to initiate some yaw but can't because it's being held. Don't let it do this, you can damage gears.
2. A gear is slipping somewhere, either the big plastic ones or the motor pinion. Superglue fixes this (be careful not to get it where you don't want it!)
3. The tail boom is broken and vibrating which confuses the gyro.

The batteries (green) have a safety circuit that prevents both overcharging AND undercharging. I KNOW about the overcharging protection and I'm pretty sure about the undercharging because I replaced my battery with one that doesn't have protection and my model doesn't shut off at all anymore.

By the way, by FAR the best thing I've done with mine is to replace the battery! I bought a GWS 1050 mAh 7.4 volt battery (about US$35) and it seems to have about twice the flying time and it lifts off at about 1/3 throttle, even though the battery is a bit heavier. If I "floor it" from standstill, it would hit the ceiling in about 2 seconds (12 ft ceilings here in New Zealand).

In fact, I used my two old batteries to power my transmitter. I dropped the vlotage (16 volts) down to 13.6 so my transmitter has a bit more ooomph than the normal 12 volt one and the batteries go for AGES and are rechargeable. I don't hink you can get away with rechargeable AA celss because they are 1.25 volts instead of 1.5 and this transmitter is sensitive to low voltage. BTW, when the remote batteries get low, the first symptom I get is that the throttle won't respond in the idle direction (slowing down).

The stock batteries should charge in 40 minutes... I measured it. The charger delivers 1 amp and the batteries are 0.850 Ah, I believe. The charge may be a bit different in the US because we have 230 volt mains here and the transformer they use there will be different. If designed correctly, though, it shouldn't matter.

The motors will burn out if you let them get too hot. If you can't keep your finger on them, give them a little rest. Accelerate the cooling by putting the model in front of a fan if you like. I get about 5 flights with cooling in between before the battery starts to show signs of discharge.

I burned out a motor once. Upon disassembly I found one brush had disappeared altogether! Overheating would have melted it I think. I wouldn't worry about burning out a motor too much. They only cost $8 here and are probably only about $6 there. I've got two new ones in stock.

Replace the tail boom with one made out of carbon fibre rod. Get 1.5mm rod at a model or kite shop and cut three equal lengths. Cut the old tail boom off the grey plastic front bit ("mount") that has the 4 screw holes and hot glue or epoxy them into the three corners of the mount. Then glue the other three ends together, run the antenna down to the end and tape it there with a bit of wire hanging out the end.

These models ARE biased to the rear for some reason. I mounted my new battery about a 1/2" forward and it STILL doesn't go forwards very fast. The canopy biases it forward by disrupting the lift at the front a bit. I never use my canopy. And I drilled five 1/4" holes in the rear tail mount to improve cooling to the rear motor as was suggested elsewhere.

If anyone wants to know anything about these feel free to email me directly at [email protected]

Cheers
Warren Harding

humveecrusher

Warren, thanks for your input!

CostaRica1

Hi guys, my experience with the HouseFly is getting better after a lot of time with the setup, but in my case the heli seems to be very...very....very sensitive in terms of forward or backward movements, the just dive the nose and goes really fast making a crash against the wall something to be afraid of....

Any tip ?

Thanks.

humveecrusher

Too much forward input? Most complain of it not being fast enough...lol. Practice....grasshopper...practice! LOL.

rocketrob28

Has anyone determined if the hrobo battery, dragonfly battery or megatech battery is the best one for the housefly? The three above mentioned all seem to be selling the same(basically) heli.

humveecrusher

The Hirobo is twice as much and has a three prong connection so prpbably won't work without an adaptor. The dragonfly battery appears to be the same and is $12.95 at Grand Hobby on eBay which is the best price that I've seen. A nother option is to buy a 7.4 V 1050 mAh 2 cell li-po which will give more power and longer flight times per Warren, but would probably require a li-po charger that senses the charge. Hope this helps.

CostaRica1

Well guys, my HouseFly is dead. Not a bad heli but is not for begginers, at least in my opinion. Too much triming, too many adjusts to be made, too much sensitive sometimes. I guess I should save money for a Sky Robo.

warren52nz

Thought I'd jump in here. Yeah, your lower assembly is (was) definitely too low. You shouldn't be able to see the splines on the shaft. I always put a bit of superglue on the spline before pushing it into place to make sure it doesn't slip. If it slips, the chopper will spin around really fast or jerk around in that direction (yaw) if it just slips a little.

When I finally got the guts to lift it up to 4 feet or so, it was like magic the way it settled down and hovered nicely. The ground effect is really sever in a little chopper like this and the counter rotating blades probably cause a lot of turbulence compared to single blade one.

Those blade holders DO give a bit of trouble. Yesterday one of mine broke off after hitting some curtains. Was surprised to see that after all the other things I've hit.

I don't use superglue anymore, I use super strength epoxy. It's a lot stronger. But it's heavier too so you've gotta watch the balance.

You should dig up my other postings in this forum.... I've written a lot including how to make your own blades. You can also get carbon fibre blades for about $30. I'll dig up the link if you're interested. I got a pair but they're a bit damaged now. BRILLIANT when new though!

efylho

Hi, i am newbie to RC.

how to make a corret trimmer?

how to make hover effect?

Thanks in advance

efylho