PDA

View Full Version : First heli, first crash


Pages : [1] 2

KILLzombi3z
01-21-2012, 06:34 AM
Well I've been lurking around for a while now, taking in bits of information here and there. I came to this forum after playing around with two different 3ch helis for some time and eventually bought a larger coaxial bird to play with. This larger bird was a no namer i bought to tinker with and it also taught me the hazards to charging Lipo batteries.

Well this all sparked an interest so I read around and settled with the Belt CP V2 as it had reviews in both direction and had a reasonable price. I must admit when i received the Belt CP i was not impressed with how it came out. Multiple little things were wrong or loose and out of place. I snagged a simulator at the same time as getting the Belt so i could get a grasp on controls an all that so the first time would be less... interesting.

I managed to go through 4 batteries or so before buying another because waiting for them to charge is a heart break!! Around the 7 flight, I had been able to keep her hovering weakly in the air with touch downs to re-orient myself when the inevitable happened. I was starting to lose control and before i could ease her down a gust of wind took it up in the air about 5 feet before i panicked and throttled down too quickly. She landed hard and immediately burst into an angry explosion of parts.

After reviewing, picking up parts, and laughing at myself for getting that "first" crash out of the way, i walked back feeling almost accomplished in a weird way. Can't really describe why but it just felt as if a benchmark had past that i knew was coming and now that little gremlin inside won't be such a pain anymore.

I know everyone in here has had that moment and can relate. Now i'm on to gathering parts and deciding on which course to go. I've got three options the way i see it. I could buy new Exi rotor and tail set up, pick up a Exi 450 Pro Carbon Fiber heli kit and swap electrics, or take the parts list to the LHS and tally up the damage and rebuild. I'm currently in South Korea and the LHS actually has a huge selection of parts.

I'd like to know what you all did after your first crash and what you wish you had done, or how it worked out for you.

gun bae!!(cheers)
:cheers


Joe

wulfrun
01-21-2012, 08:43 AM
I think we can all say we've been there. My first crash with my Belt CP was too long ago to remember, there have been a few since!

I'd take stock of what's broken first and see if it's worth fixing. If you fix it, consider making some sensible changes rather than put it back to stock. There are various weak points on the model and if you do some digging on here and other places you can see what makes sense to upgrade or change. Some parts from other models fit and are better quality, for instance.

If you're using the stock electrics I would say they aren't the best, by any stretch of the imagination. Think twice about putting them into another model. If you think the hobby is really for you, why not invest in a good set of electrics - Radio/receiver/gyro/servos/ESC? As long as you buy decent gear it will be a good investment and pay for itself by surviving crashes better and actually working properly, not to mention the big advantages of programmable radios in taming things down for a beginner.

What would I have done different from the start? Nothing really, the Belt CP has taught me a lot. If I'd splashed out on a T-Rex 600 or something like that, I'd probably have left it at a pile of expensive junk after a proper crash! Since the Belt was fairly cheap to fix, I did just that and I've made a series of changes since. It still has the original frame, motor and boom - that's about all!

giorgos_cupra
01-21-2012, 09:02 AM
Hey Killz,thanx for sharing your first crash,brings back a lot of memories:face.

I must admit though,i was extremely lucky on my first crashes.I had the belt for 2-3 years and crashed only twice.The first ever time,somehow the heli turned nose in to me.At the time i couldn't even hover properly tail in.I dumb thumbed it and only destroyed main blades and the whole flybar system.Next time i was doing figures of 8 and stuff....Lost my orientation and crashed the heli exactly in the front of my brand new reiger bumper.I destroyed the blades and chipped my fusuno canopy.Damage on the bumper,just a small scratch.The big crash came later on,when i moved to a raptor 50.A servo burnt mid air and crashed the $hit out of it!Came around to 350$ of damage and new servos.

I say fix the belt...Buy a new head from ebay or anywhere else as cheap as you can.You are going to crash a lot and you dont wanna do that with a heli you plan to keep.Crash the hell out of it and then ditch it,switch to an exi/tarot or even better to a t-rex.

As wulfrun said,electronics are crap.You can at least change servos and esc.I had cheap tower servos on mine that were far better than the stock.Also i had an turnigy esc also for dirt cheap and never had problems.Furthermore you can get an hk401b,for 12$ or something,do the appropriete mod and it will be far far better than stock.Those are all good upgrades and very cheap.If you later move on to a better heli,you will neeb better electronics and of course a dx6i at least.

Edit:As to what i do after a crash?Nothing...Fix it and go on...Crashes are a big part of this hobby.You know,there are pilots that have crashed and pilots that will crash;)

KILLzombi3z
01-21-2012, 10:05 AM
Thank you for the replies!

I have to say, at first I was curious how i was going to be able to sort through and recognize everything that would need to be replaced. After staring at it for a minute it started to become obvious. It seems that these heli's will make it apparent what needs to be replaced. The feathering shaft alone turned into a banana... lol.

I took your advice and made a list of what was just plain broken and also parts that could've been damaged in association.

I see what you guys are saying about the servos. Junk! With the motor unplugged i noticed the tail motor was slightly erratic under operation. Almost like a jittery trait to it and wouldn't return to center without more playing around. The tail blade set up is weak as well. A lot of unwanted play. I'm a mechanic by trade and i don't like seeing all that excess in an area that is suppose to "precisely" control movement.

What's good about Exi? I've been reading around and these seem to be a good replacement choice? I don't want to get to far into it at the moment because i am just starting albeit eager, but don't want to dive in and drown myself in a hobby i may lose interest in. I don't think that'll happen just yet being that these suckers are so damn interesting to look at and figure out let alone fly and work on them.

wulfrun
01-21-2012, 10:29 AM
Post a list of what's definitely broken and what might be damaged. You'll get a load of suggestions as to what to replace with if you go the repair route.

If the feathering shaft's banana-shaped you're likely to need main shaft/feathering shaft/blades and very possibly a servo or two and main gear as a minimum. For what they cost, just replace the servos outright with something better. If the head is trashed there are better ones for not much more money. The Eflite Blade 400 main gear drops straight in and is a lot tougher. Mine also has the Turnigy ESC and I have the HK401 gyro. No, they aren't top-notch but they're fine for me and better than stock.

Half the fun is fixing it, you'll learn a lot more that way. He who never crashes, never flies.

KILLzombi3z
01-21-2012, 11:03 AM
Right now i'm sitting at:

Blades
Feathering shaft
Flybar
Main shaft
Main gear
Tail boom
Paddles - only because they came practically welded on and the set screws are stripped
Tail blade clamp set
Bell controller arm
Flybar control arms
balancing pole mounting

And more than likely a few more in the process.

I'm finding that some of the hardware is in there so good it's stripping out the bolt or breaking. Not good to have happen if you ask me but it'll all be fixed eventually.

How does one check a servo to insure proper operation? What should i be looking for in a low cost replacement?

Tomstoy2
01-21-2012, 11:30 AM
I must have crashed mine a hunderd times!
First time was on my first spool up. After that, damn near every flight. Eventually, crashes became further apart.

I spent far too much money repairing it and modding it, but it did teach me so much, and that really was necessary for me to learn for the heli I eventually replaced it with.

I say to rebuild her, but first check out the super-sticky above and then go from there.
A lot of parts from the Trex are interchangable with the Belt, but the sticky will tell you which ones as not all are. Plus, Trex makes so many variants that it's important to get the correct parts.

The EXI head is a good replacement and makes a huge difference, especially at the price.

It's one thing to crash it because you made a mistake, it's another thing all together when you crash because a cheap component failed. That's when it really hurts the most.

There is a lot of grabage out there so be careful on what you spend your money on.

The advise you got above from the other guys is all good. If you get stuck, ask away here. We all try to help get you back into the air as quickly as possible.

This hobby is not for all, but I think if you stick with it you will find it so addictive you will never get bored. There is always something new to learn and so many directions you can take it to that it will entertain you for a life time.
I've been flying something or another for over 51 years now and I continue to learn every time I fly.

Good luck, and welcome to the forum!

ChopperNoob
01-21-2012, 11:49 AM
Welcome, I've crashed mine 3 times already and ive not had it long. The main thing I've had to replace are 3 feathering shafts, 3 main gears, 1 flybar, 2 sets of main rotors, 1 tail boom, 1 main shaft. The parts are cheap and easy to replace, it's the setting up that counts. Get a pitch gauge and learn how to set the pitch, tracking and balancing otherwise any upgrades will be useless if not set up right. Personally I'm not upgrading my belt at all as its a learning helicopter and I've figured if I can fly this as it came out the box I can fly anything! Is it worth spending 40 pounds on a better head if your only gonna crash it and bend it instead of the cheapo plastic one? That's up to you, but good luck and you've come to the right place for help and encouragement!

wulfrun
01-21-2012, 03:39 PM
Right now i'm sitting at:

Blades
Feathering shaft
Flybar
Main shaft
Main gear
Tail boom
Paddles - only because they came practically welded on and the set screws are stripped
Tail blade clamp set
Bell controller arm
Flybar control arms
balancing pole mounting

And more than likely a few more in the process.

I'm finding that some of the hardware is in there so good it's stripping out the bolt or breaking. Not good to have happen if you ask me but it'll all be fixed eventually.

How does one check a servo to insure proper operation? What should i be looking for in a low cost replacement?
That's a fair old list. Might be worth considering a new head when you add it all up. Don't put a stock main gear back in it, a cheaper and stronger replacement is the one for the Eflite Blade 400 (straight swap) but there are others too. The standard one strips out just by looking at it the wrong way, it's too soft by far.

To test a servo, disconnect the linkage to it and disconnect any two wires from the main motor (all 3 if you prefer but 2 is enough). Power up and get the servo to move through its entire travel, slowly. It shouldn't jitter or jump around or fail to follow the stick movement at any point. Worth just applying some finger pressure to make sure it has no missing gear teeth, you'll feel it if it has. It should have about 90 degrees total movement. It should also always return to centre smartly when you release the stick (well, to wherever it was at the start anyway). That's a fairly basic test but good enough to find most flaws.

Hard to say what to look for in a replacement, depends a lot on your budget. Cheapest are plastic gears, next come resin gears and dearest are metal or carbon gears. Ball-bearing output shafts are desirable but add cost. Stick with a reputable make and don't go too cheap, they'll only break again. Also, make sure all three cyclic servos are the same make/model, don't ever mix & match or you're inviting problems. I'm sure you'll get plenty of recommendations if you wait for folk to chip in. My Belt CP has Hextronik HXT900 resin-gear servos which were not expensive. They've been fine so far but I won't claim they're anything special.

KILLzombi3z
01-21-2012, 08:22 PM
I can understand both sides to swapping a head for a new one verse rebuilding the old one. I do think that the original head has a lot of play between input and output points with in the linkage.

Wulfrun, thank you for the bit on the main gear. I'll be asking for that today when i go off to the LHS. Also, testing the servo seems straight forward after you mention it. If all is well i may stick with what i got for budget reasons unless replacement costs stick low.

One issue i was having pre-crash is the bird always wanted to move cyclic left. And i eventually got to the point where the cyclic trim control was all the way opposite to counteract this with only a minimal difference. In hover for me i found i was always counteracting for this one problem alone making learning to hover a bit tricky before i started to realize this constant drift. I've had her about 4-5ft in a hover and this still occured which would eliminate ground effect as a culprit?

Well, off to the LHS to look into my options and see which route I'm going to take. Wish me luck!

KILLzombi3z
01-21-2012, 11:08 PM
Went down to the LHS to sort things out. I ended up buying replacement parts for two reasons. One, it added up to about the same as my other two choices, and secondly, they didn't have anything else but OEM replacement parts.

A little bit of me wished they had any upgraded parts. Just seems worth it when they're mostly the same price or cheaper. I could have ordered a whole head assembly to drop in. And they offer a bit better performance.

The only thing i don't have is a pitch gauge. I know this is a biggie but the LHS was pushing some $20 Align gauge on me and the bill was already up there. They offer for me to bring in the heli after i rebuild it to double check my work and set the blade pitch and tracking. Seemed the way to go when i can get a PG online for cheaper.

The only reason i didn't buy anything online is due to me being in the military and I'll be leaving my current location very soon. I won't be able to get anything in the mail in time and rushing the shipment to an APO address isn't even an option.

I'm going to start ordering things at my next location bit by bit so that i can have parts on hand, also proper tools. The trip out to the LHS and back is a little exhausting and i don't know where the next will be.

Let the rebuilding begin!

Tomstoy2
01-22-2012, 02:06 AM
I hope it's not Afganistan! My son is in the infantry at a fob there, scares me to death. He rotates home in about 7 more weeks, though, thank God!

No matter where you are, people here are world wide and can help you locate whatever you need, so feel free to ask away for help.

Good luck!

KILLzombi3z
01-22-2012, 04:46 AM
Thanks Tomstoy2, I appreciate it!

No, not deployed or anything at the moment. I hope your son has a safe and speedy return. It's no fun over there.

So I had went back to the LHS after putting some things back together to ask questions. Like how tight certain things should be and what not. Turns out the guy helping me was the regional champ and is ranked around 26th in the world competitively speaking. Crazy! They told me to put it all together and bring it in for them to check over and that he (the champ) can fly anything and not to worry. I believed them :thumbup:

ChopperNoob
01-22-2012, 08:35 AM
Good luck with the head rebuild, ive found it a valuable experience doing mine. As for the drifting left, all the belts do it apparently, mine certainly does. How to stop it I'm not sure but like I said earlier "if you can fly this thing you can fly anything"!
I'm waiting for the wind to die down here so I can give mine a test flight after the recent work I did on her. Hopefully it won't end in disaster.

sutty
01-22-2012, 12:05 PM
All clockwise rotating helis do it, not just the Belt. Anticlockwise on the mainblades and it would drift right as the anti torque rotor, tail rotor, would have to be on the left. Nothing that can be done about it. In order to conteract the torque from the main rotor, you have to provide a thrust from the tail out to the right. Mains go clockwise, body goes anticlockwise, or nose left, and as a consequence tail goes right. In order to stop it you have to provide a thrust out to the right, to push the tail left. This left thrust, balanced at the front by the torque, forces the heli to drift left. The only thing that can be done to stop it is to hold a small amount of right cyclic in, which causes the heli to hang off to the right slightly. If you trim it out, then it will pull off to the right when you start to fly about, or roll to the right and slightly corkscrew out of a loop for example. This is absolutely typical, and something you get totally used to, and will compensate for it without even thinking about it.

Here is a video of me showing exactly what it looks like from behind on the Belt. Least I think it was the Belt. Probably some half and half hybrid creature. Although it might get less when higher, not much, it is just harder to see, it really doesn't matter, you have to do it, and you will do it without thought, soon enough.

7eV1wU0Wpn0

Cheers

Sutty

KILLzombi3z
01-22-2012, 09:00 PM
So i went through and put things back together. very interesting and fun to say the least. I took the time to set up all the linkages and level out the swash the best i could. Ended up using a small piece from the fly bar to bend around and drop in the main shaft to use as a make shift leveler.

I see what you're getting at with the torque of the bird and the tail rotors counteraction to it. Makes sense why it'd want to drift off to the left. Thing was i was having trouble trimming it out but never got it perfect. I can live with the little bit that it's doing right now.

One thing i ran into while setting pitch. The "champ" from the hobby store was saying while the radio is in idle up, hov pitch dial to middle, and throttle to mid stick, set pitch to +3. I don't know if i lost anything in translation, but when i go back to normal mode and bring the throttle all the way down i never get any negative pitch. And this is something i've been reading is a bad thing. I think today i'm going to set it at 0 degrees like it should and recheck from there.

Tomstoy2
01-22-2012, 09:12 PM
You will only go into negative pitch in idle up mode, not normal. This is why it is so important to set it up in idle up as he instructed.

As far as the +3 degrees of pitch in idle up is concerned, this is dependent upon your heli.
The idea here is at mid-stick you want it to hover.
Weight, headspeed, type of main blades used, and a few other factors will determine how much pitch you need at mid-stick in idle up.
Like I said, the idea is to get it to hold altitude at mid stick in idle up.

chansen1953
01-22-2012, 09:42 PM
also, KILLzombi3z (http://www.helifreak.com/member.php?u=151193), I'd recommend you go and get spares now, before your next appointment with the ground !!1

for a BELt CP, the recommended spares are

several sets of "woodie" blades ( very cheap, and cause less damage if hit the boom)
several spare tail booms.. as nearly always get hit in a crash
several feathering shafts and main shafts.. these will get bent often..
fly bar.. can be straitened a few times, but keep at least one spare..
tail blades.. keep a few spares.
main gears - use the exi one, but keep a few spares handy
a spare set of skids and skid rails are also good spares..

All of the above spares should cost less than $40 , and will keep you flying for lots of flights..
good luck with it mate !1

KILLzombi3z
01-23-2012, 12:47 AM
Thanks for the tid bit Tomstoy2. I thought there was a little bit of negative pitch in normal mode to keep it on the ground but head speed would make sense. Today i'm going to go back through my work and double check it before the LHS takes a peek at it.

Thanks for the advice on spares chansen1953. I have some of those parts right now from this crash being that some of the parts came in pairs and what not. I want to get one of those segregated containers and build a little rebuild kit to keep me in business the next time i high five the ground.

Tomstoy2
01-23-2012, 02:00 AM
Get yourself a nice plastic case at Wallmart, or somewhere, to store her in and keep it safe, too. Being in the military, you never know where you might need to take it.

KILLzombi3z
01-23-2012, 02:29 AM
Looking into that Tomstoy2, as well as eventually getting a case for the bird itself. Right now I'm just going to use the box that it came in but eventually I'd like to get something a bit more legit.

jperkosk
01-23-2012, 04:13 AM
You will only go into negative pitch in idle up mode, not normal. This is why it is so important to set it up in idle up as he instructed.


That's not quite correct, Tom, you've forgotten how to fly in normal mode, haven't you? :rotf

I thought there was a little bit of negative pitch in normal mode to keep it on the ground but head speed would make sense. Today i'm going to go back through my work and double check it before the LHS takes a peek at it.


That is quite correct, you need a bit of negative pitch in normal mode for two reasons:

It'll help you keep the heli on the ground while spooling up.
It'll give you some collective authority in windy conditions. It means it'll help you bring the heli back down when the gust of wind picks it up. Without the negative pitch you're doomed.

The best normal pitch curve for the Belt is about -3 deg at the stick full down and +7 deg full up. Now what's the best pitch in the center stick is a bit of a disputed matter.

Most of us setup the birds to have 0 deg center stick whether in normal mode or idle up. This is for two reasons:


It helps you get the headspeed up before lifting off. Stock Belt has a low headspeed, a bit more RPM helps the stability in the air (but it also increases the crash damage)
It makes for smooth transition between normal and idle-up modes later on when you'll start using idle-up mode. Mind you, idle-up mode is absolutely necessary when inverting the heli, but it's also very helpful in normal flying because of better collective authority.

So the most common setup for the Belt would be something like this (low/center/high stick):
normal mode -3/0/+7 idle-up mode -7/0/+7

Now all that said with standard radio it's almost impossible to set-up pitch and RPM (throttle) curves to match above center stick (that's what you need for smooth "jumpless" transition between normal and idle-up modes), you need computer radio for that. But this is something you'll need to worry a bit later, when you're comfortable at hovering around in all orientations. For now, tape this idle-up switch in "off" position, and there is really no harm in having a couple of degrees of positive pitch at center stick in normal mode, but I strongly recommend to have at least -3 deg at low stick.

KILLzombi3z
01-23-2012, 06:12 AM
Thank you very much for the advice Jperkosk.

Right now i'm having major vibrations. I weighted the bird down sticking something through the skids and put dumbells on that. I was trying to check the tracking, which was spot on, but this gnarly vibration would shake the heli. something is clearly out of balance somewhere.

I didn't look to hard at it. I did recheck that the fly bar was evenly spaced and it is exactly centered. Tomorrow the LHS should be able to figure it out. i'm hoping i didn't put in a bent main shaft right out of the package. We'll see though.

I must say it was a bit discouraging having a big unbalance like that after building it up the first time but it isn't that surprising to me. There's a lot to this hobby i'm not aware of yet and i'm surely just not seeing something completely obvious to the experiences enthusiast.

jperkosk
01-23-2012, 08:07 AM
Have you balanced the blades? Stock Esky blades are usually out of balance out of the box. Have you checked the feathering shaft? That's the one that connects two blade grips together. If it doesn't roll smoothly on the glass then it's bent and will produce vibrations.

giorgos_cupra
01-23-2012, 09:46 AM
Jerry is right.You need negative pitch in normal,in case of the common effect of balooning.Meaning gusts of wind lifting your heli up as Jerry said.A good pitch curve for a beginner is -4/3/8.Start from there and adjust accordingly.If you see that when you bring the stick down the heli drops like a brick,increase low stick pitch eg from -4 to -3.

If you feel you have a very low head speed and the heli feels somewhat sluggish and unstable decrease from 3 to 2 or 1.A low headspeed also makes your tail not holding.

Also it is very common for all the helis to seem out of balance and "chicken dance" in low rpms.Spool her up until it's light on it's skids.If the unbalancing condition continues,you have a problem,if not you are good to go