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Old Nov 26, 2012, 07:16 PM
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Australia, VIC
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Build guide

https://hotfile.com/dl/162805261/562...Guide.pdf.html

I wrote a guide : for building plastic fantastic
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Old Nov 26, 2012, 09:50 PM
Red Merle ALES
Curtis Suter's Avatar
United States, Mt, Helena
Joined Apr 2002
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Originally Posted by old4570 View Post
https://hotfile.com/dl/162805261/562...Guide.pdf.html

I wrote a guide : for building plastic fantastic
And a very good guide it is!

Thanks for doing this.

Curtis
Montana
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Old Dec 13, 2012, 08:26 PM
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Singapore, Singapore
Joined Dec 2012
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Hey guys, I'm sorry, I know this thread is old, but I got myself a RTF 450 from eBay for EUR 80, and when I try to spool up, I get nasty vibrations on the tail and main rotor head, I can't even lift off properly. So now I'm very afraid of getting anything else off eBay, until someone can tell me whether these things in fact do work. I was looking at this thread and saw that you guys have an amazing build on the cheap that can actually fly.

So I have a few questions:

Are your parts shipped from China?

Where do you get those kits for real cheap? (I went to Parts4hobby on eBay and there were only 5 parts available, no kits, nothing.)

Since my main rotor is wobbly, and my tail isn't that great either, would buying these parts help? (http://www.ebay.com.sg/itm/Aluminium...ht_2863wt_1028) Or would these cheap parts be faulty themselves and become wobbly again?

Thanks for everything guys, I hope I can just get my heli to hover without vibrations and wobble.
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Old Dec 14, 2012, 05:24 AM
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Australia, VIC
Joined Dec 2011
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Christmas

Quote:
Originally Posted by perdification View Post
Hey guys, I'm sorry, I know this thread is old, but I got myself a RTF 450 from eBay for EUR 80, and when I try to spool up, I get nasty vibrations on the tail and main rotor head, I can't even lift off properly. So now I'm very afraid of getting anything else off eBay, until someone can tell me whether these things in fact do work. I was looking at this thread and saw that you guys have an amazing build on the cheap that can actually fly.

So I have a few questions:

Are your parts shipped from China?

Where do you get those kits for real cheap? (I went to Parts4hobby on eBay and there were only 5 parts available, no kits, nothing.)

Since my main rotor is wobbly, and my tail isn't that great either, would buying these parts help? (http://www.ebay.com.sg/itm/Aluminium...ht_2863wt_1028) Or would these cheap parts be faulty themselves and become wobbly again?

Thanks for everything guys, I hope I can just get my heli to hover without vibrations and wobble.
Christmas gouge has begun - prices have gone up ...

Cheapest kit now is about $40 ... Check out HobbyKing , the HK450 for $28 + Shipping is looking better than ever ... I might buy one as there in stock ..

As for vibration :

Balance the rotor blades :
I also balance the rotor head by using flybar weights :

Remove rotor blades : Make sure your flybar has flybar weights ..

Spin up the head , and use the flybar weights to smooth it out - bit like wheel balancing ..

Now when you put on your balanced rotor blades it should be smooth ..
Remember not to over tighten the rotor blades , as they need to self align as the head spins , so they need to be able to move back and forth without to much force .

It pays to check everything before attempting to fly ..

Check to make sure the head is thread locked .
Check that rotor blades are balanced
Check flybar - nice and even both sides .. Now to balance you can slide flybar back and forth [ nasty way ] or add flybar weights and set the flybar nice and even , and use the flybar weights to get it as smooth as possible ..

Yes , the tail can vibrate as well , weight the tail rotor blades , make sure there as close as possible ..
Check for slop in the tail rotor shaft - Too much play can = vibration ..
More flybar weight = more stability - Ive had up to 5 flybar weights on each side of my flybar ..

Rotor head speed , I usually aim for the slowest rotor head speed - that avoided porpoising .

Buying a kit [ RTF ] is only the first step , 2nd thing is to verify everything is ok ..
I would strongly urge you to find some one local that can help you avoid some of the pitfalls ..
Doing it on your own , is taking the hard road [ been there ] , I suggest the easy road [ get help ]
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Old Dec 14, 2012, 05:44 AM
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Greasby England
Joined Sep 2008
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My 450 arrived with a bent feathering shaft which caused a lot of vibration.
Alan
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Old Dec 14, 2012, 06:13 AM
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Australia, VIC
Joined Dec 2011
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How To Check Your Feathering Shaft The Easy Way (2 min 27 sec)
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Old Dec 14, 2012, 06:19 AM
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Singapore, Singapore
Joined Dec 2012
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Quote:
Originally Posted by old4570 View Post
Christmas gouge has begun - prices have gone up ...

Cheapest kit now is about $40 ... Check out HobbyKing , the HK450 for $28 + Shipping is looking better than ever ... I might buy one as there in stock ..

As for vibration :

Balance the rotor blades :
I also balance the rotor head by using flybar weights :

Remove rotor blades : Make sure your flybar has flybar weights ..

Spin up the head , and use the flybar weights to smooth it out - bit like wheel balancing ..

Now when you put on your balanced rotor blades it should be smooth ..
Remember not to over tighten the rotor blades , as they need to self align as the head spins , so they need to be able to move back and forth without to much force .

It pays to check everything before attempting to fly ..

Check to make sure the head is thread locked .
Check that rotor blades are balanced
Check flybar - nice and even both sides .. Now to balance you can slide flybar back and forth [ nasty way ] or add flybar weights and set the flybar nice and even , and use the flybar weights to get it as smooth as possible ..

Yes , the tail can vibrate as well , weight the tail rotor blades , make sure there as close as possible ..
Check for slop in the tail rotor shaft - Too much play can = vibration ..
More flybar weight = more stability - Ive had up to 5 flybar weights on each side of my flybar ..

Rotor head speed , I usually aim for the slowest rotor head speed - that avoided porpoising .

Buying a kit [ RTF ] is only the first step , 2nd thing is to verify everything is ok ..
I would strongly urge you to find some one local that can help you avoid some of the pitfalls ..
Doing it on your own , is taking the hard road [ been there ] , I suggest the easy road [ get help ]
Many thanks for all the suggestions. I've done everything, blade balancing and tracking and balanced even my tail blades. Nothing worked, so I swapped out the bearings and tail and main shafts, now it vibrates still, but much less than before, definitely. I need to know what's the normal level of vibration to be expected on the tail especially. My vertical tail fin, at full throttle, without main blades and flybar paddles, has the bottom 40 % vibrating to the extent that it turns into a blur of roughly 0.4cm across when viewed from the back. Is this normal?

Also, are the CNC heads that I posted in the ebay link in my previous post reliable? I've never had experience with them, so I thought I'd ask someone who tried it out first. Will the cheap CNC aluminium heads cause a lot of vibrations?

Thanks again.
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Old Dec 14, 2012, 07:55 AM
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United States, FL, Hernando
Joined Sep 2012
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Just a quick mention, I just got my $28.00 HK 450, its a nice unit except for the tail assy. The plastic is horrendous and it likes to bind at very little of center. I would order the metal one from HK for the 450 V2 along with the kit.

Oh BTW, good thread
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Old Dec 14, 2012, 08:18 AM
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Australia, VIC
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No

Quote:
Originally Posted by perdification View Post
Many thanks for all the suggestions. I've done everything, blade balancing and tracking and balanced even my tail blades. Nothing worked, so I swapped out the bearings and tail and main shafts, now it vibrates still, but much less than before, definitely. I need to know what's the normal level of vibration to be expected on the tail especially. My vertical tail fin, at full throttle, without main blades and flybar paddles, has the bottom 40 % vibrating to the extent that it turns into a blur of roughly 0.4cm across when viewed from the back. Is this normal?

Also, are the CNC heads that I posted in the ebay link in my previous post reliable? I've never had experience with them, so I thought I'd ask someone who tried it out first. Will the cheap CNC aluminium heads cause a lot of vibrations?

Thanks again.
Sounds like something is amiss ..

Remove the tail rotor blades - did the vibration go away ?
Check the tail rotor shaft - is there much play - is the tail rotor shaft bent ?
Also check to see if the tail rotor drive belt is too tight or too loose ..

Check motor pinion to main drive cog fit , you want a few thou play all the way around [ no binding ]

Also the flybar control arm - check for play ...
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Old Dec 14, 2012, 08:48 AM
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Singapore, Singapore
Joined Dec 2012
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Quote:
Originally Posted by old4570 View Post
Sounds like something is amiss ..

Remove the tail rotor blades - did the vibration go away ?
Check the tail rotor shaft - is there much play - is the tail rotor shaft bent ?
Also check to see if the tail rotor drive belt is too tight or too loose ..

Check motor pinion to main drive cog fit , you want a few thou play all the way around [ no binding ]

Also the flybar control arm - check for play ...
This is what I've done so far. Replaced tail blades, tail shaft, tail bearings, main shaft, main bearings. I end up with a vibration on the bottom 30% of the vertical tail fin that forms a blur of 0.4 cm at full throttle. The tail belt, i use a screwdriver and with moderate force, can push it slightly across the center line.

The pinion to main gear, from what I can see, is not too tight a fit and has some room to play as well. People say that it's impossible to eliminate these vibes in a cheap heli like mine. But does it happen to yours as well? Try looking at the bottom half of your vertical tail fin. Does it form a blur for yours?

Thanks.
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Old Dec 14, 2012, 09:28 AM
FPV Noob KD0VMK
United States, MO, Platte City
Joined Jun 2012
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Quote:
Originally Posted by perdification View Post
This is what I've done so far. Replaced tail blades, tail shaft, tail bearings, main shaft, main bearings. I end up with a vibration on the bottom 30% of the vertical tail fin that forms a blur of 0.4 cm at full throttle. The tail belt, i use a screwdriver and with moderate force, can push it slightly across the center line.
I'm fighting the exact same thing on mine after a switch to a CF tail boom (I crashed my last Aluminum one, CF is all I had). Mine becomes a blur around 60% throttle, and smooths out after that. It's such a violent vibration, it actually hurts a bit to hang onto the tail boom. It shakes the tail boom support and the tail assembly loose, changing the belt tension as well.

My blades are balanced to within .001 gram according my jewelry scale. The shaft isn't bent, everything looks perfect. I'm totally stumped.

I ordered a totally new tail assembly for an EXI. It should be here any day, i'll let you know if it solves the problem. Otherwise, I'm just going to put it all back together and fly it. I'm tired of screwing with the stupid tail, and with any luck, the main rotor might help cancel some of the bad vibes (all my tests have been with no rotor head)
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Old Dec 14, 2012, 09:36 AM
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Singapore, Singapore
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Originally Posted by Chubbs View Post
I'm fighting the exact same thing on mine after a switch to a CF tail boom (I crashed my last Aluminum one, CF is all I had). Mine becomes a blur around 60% throttle, and smooths out after that. It's such a violent vibration, it actually hurts a bit to hang onto the tail boom. It shakes the tail boom support and the tail assembly loose, changing the belt tension as well.

My blades are balanced to within .001 gram according my jewelry scale. The shaft isn't bent, everything looks perfect. I'm totally stumped.

I ordered a totally new tail assembly for an EXI. It should be here any day, i'll let you know if it solves the problem. Otherwise, I'm just going to put it all back together and fly it. I'm tired of screwing with the stupid tail, and with any luck, the main rotor might help cancel some of the bad vibes (all my tests have been with no rotor head)
They all say that CNC aluminium tails and rotor heads help reduce vibration, but I don't know if it's true for the cheap eBay ones that I see. I've been asking around about whether anyone has had experiences with these, but I haven't got a reply yet. Maybe if you buy a set, since it's so cheap, it may well solve your problem. (But don't take my word! I'm a total newbie here.)
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Old Dec 14, 2012, 01:07 PM
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i went onto parts4hobby and it only had 4-5 motors for sale
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Old Dec 14, 2012, 05:07 PM
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Joined Dec 2011
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http://www.ebay.com/itm/Hobbymate-HB...item4167a24729

http://www.hobbyking.com/hobbyking/s...er_3200KV.html

http://www.hobbyking.com/hobbyking/s...tor_420w_.html

No particular order ...

If your looking for bargains , you need to troll ebay ..
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Old Dec 14, 2012, 05:38 PM
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Quote:
Originally Posted by perdification View Post
This is what I've done so far. Replaced tail blades, tail shaft, tail bearings, main shaft, main bearings. I end up with a vibration on the bottom 30% of the vertical tail fin that forms a blur of 0.4 cm at full throttle. The tail belt, i use a screwdriver and with moderate force, can push it slightly across the center line.

The pinion to main gear, from what I can see, is not too tight a fit and has some room to play as well. People say that it's impossible to eliminate these vibes in a cheap heli like mine. But does it happen to yours as well? Try looking at the bottom half of your vertical tail fin. Does it form a blur for yours?

Thanks.
you need to isolate the cause ... Throwing parts at it without knowing the actual source ..

Here is your problem ! Frequency of the actual vibration ...


A vibration that looks like its coming from one source [ like tail ] may actually not !

Because the vibration may travel down the tail boom and manifest itself at the tail rotor and there fore look like the source .. So you need to systematically track down the cause ..

Now it can be the head , the tail rotor , the motor , drive belt tension ...

You need to think carefully , did you isolate the problem [ track down the source ] , simply replacing parts , does not necessarily fix anything .

So please ! Take a moment ...

Remove all rotor blades - head and tail ... Run the heli on the ground ..
Does it vibrate ?

Very important - weighing blades does not = balancing
Buy a balancer - http://www.ebay.com/itm/TL10289-Taro...item1e700ba0e8

Go ahead and weigh the blades - after that balance them ... If all you have done is weigh blades then this could be the root cause of your problems ..

There are 3 things you can do to dynamically balance your blades ..
Weigh them , find the center of gravity [ balance point ] and then with a blade balancer , actually balance the blades ..

If your serious enough , you try to match on all 3 , I was lucky - I actually bought a set of blades so balanced , and they ran supper sweet ! But just using a actual blade balancer , will fix blade balancing . [ Vibration issues ]

Again , it comes down to tracking down the cause , that means systematically testing components ...


At this point here is what I would do ...

Remove all rotor blades : Run the heli on the ground - in your hand - what ever !
If it vibrates - I would remove the tail rotor belt from the pinion driven by the main gear set , and than run the heli again so its just the head spinning ..

Does it vibrate ? Its either yes or no [ 50/50 ] unless there is more than one source ...

If its YES ! I would pull the head off , and just run the motor ..

Does it vibrate ? if it vibrates - there you go , if not ..

Then it was the Head [ possibly or main drive gear ] anyhow ..

I would check everything on the head that moves for excessive play ..

No 1 suspect - Flybar alignment [ nice and central ] flybar control arm play ..

Again , if all checks out , I would add flybar weights to the flybar , and then use them to balance the head [ like wheel balancing ]

Add a flybar weight to each end near the flybar paddles - I would also use my dial calipers to check that the flybar is even , the paddles are the same distance from the head ..

I would mark one weight with a marker pen .. Run the heli , and if it vibrates , move one of the flybar weights about 0.5mm towards the head .. And test run again ? Vibrates less or more ? If it were less , I would move the flybar weight another 0.5mm [ half mm ] towards the head until I got the head to run as smooth as possible ..

If it were made worse . I would put it back to the starting point [ flybar weight ] and move to the other side and try moving that flybar weight in half a mill at a time till there was improvement .

Sometimes the head itself might be out of balance for what ever reason .

Now if its the tail : well I got to go out right now but , please check .. At least check if its the head or tail by isolating one [ has to be the tail - to be isolated ] and then test run .
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