Take Off - Flybarless

[David Drew]

After an 'event' with my Goblin 500 when trying to get it light on the skids to check setup I thought I had better ask what differences there are to taking off with fbl as against flybar.

With fb I can get the heli light on the skids in order to check tail and cyclics actions and generally get a feel of the balance of the heli.

With my Mcxp and 130x if I hesitate just before takeoff they fall over to the left and crash - not a problem as they are well able to cope with that - but with a 500 it's a different matter.

So, tips and advice please.

Arm at the take-off site and don't change the orientation?

Get it off the ground quick? Grab the controls when off the ground?

You've all been through it. So what do you do?

Thanks

David

[George J]

More often than not the heli will be in a different position to where I power it up/start it, makes no difference apart from straightening the tail as normal. Personally I just pop the heli off the ground but it's not true that you shouldn't touch the sticks if you need to when taking off with a FBL heli.

[jwatts007]

I am using V Bar and Skookum FBL gyros and taking off from a wooden platform at out field due too a very muddy field...I can put the helis into idle up and give it plenty off rudder and let them spin round and round then take off...I dont touch the cyclic though...its just a bit of fun but goes too show they dont flip over by themselves....

[David Drew]

The worry I have is popping the heli off the ground only to find it does not react as I want it to. I am AOK with fb.

I guess a test is to take the blades off and manually tilt the heli to see if the swash moves to correct with no cyclic input.

I have experienced help locally so I will be guided by them but I do want to know what to expect.

[Planehazza]

I've had a few instances of FBL tipping over on take off and it's always been due to a vibration issue.

[David Drew]

I've had a few instances of FBL tipping over on take off and it's always been due to a vibration issue.

Interesting!

The Brain is mounted on one of the supplied pads. I will check wiring to make sure servo wires are not inputting vibration.

Problem is - if vibration is the problem the Brain is supposed to be tolerant to vibration and I bet the makers won't pay for the crash damage. Plus, prove it!

[jwatts007]

The worry I have is popping the heli off the ground only to find it does not react as I want it to. I am AOK with fb.

I guess a test is to take the blades off and manually tilt the heli to see if the swash moves to correct with no cyclic input.

I have experienced help locally so I will be guided by them but I do want to know what to expect.

As long as you have sensor direction correct you will be ok...get it wrong and it is very nasty...

[David Drew]

As long as you have sensor direction correct you will be ok...get it wrong and it is very nasty...

Guess wiggling the heli to what the servos do will tell if sensor direction is good.

[dillwhacker]

I always take all 4 blades off and watch the swash over the whole RPM range.
Surely wiggling the heli and watching the swash is an essential part of any FBL setup?
My 500 with BeastX I can make go light on the skids and move about a little in the mud just like FB and nothing horrid happens.

[pgkevet]

If it's the first fitting (post repair maiden) ect then generally a good idea to run it up blades-off. Things like checking cyclic responses etc is part of pre-flight not takeoff. With both my beastx and brain helis I have no concerns about gental spool-ups and adjustments during take-off. If one is heavy hadned and bounes an fbl heli on the ground during takeoff then I could imagine some interesting ground resonannce effects..

[Ade_Law]

I treat them like a heading hold gyro, during spool up give everything a wiggle to make sure its flat and centred, that way you know the fbl is not trying to put the heli into an orientation that it shouldn't be.

Ade

[iceuk]

do not touch cyclic whilst increasing throttle, once it gets in the air then use cyclic,

[George J]

I don't know anyone and it's not happened to me either having a FBL heli tip over on spool up, that will only happen if it's set up wrong or you have a decent vibration issue. If the swash and tail are moving in the correct direction when you tilt the heli and the heli is mechanically good then you'll have no problems, just get it light and pop it off the ground.
I have vbar on my helis and I can move the heli around on the ground when it's spooled up with no issues and it doesn't want to tip over.

[iceuk]

I treat them like a heading hold gyro, during spool up give everything a wiggle to make sure its flat and centred, that way you know the fbl is not trying to put the heli into an orientation that it shouldn't be.

Ade

Bit late to find out the FBL system is trying to put the heli into a orientation that it shouldn't be if your spooling up, that's what PRE-Flight checks are for.

[Ade_Law]

Bit late to find out the FBL system is trying to put the heli into a orientation that it shouldn't be if your spooling up, that's what PRE-Flight checks are for.

I'm not talking about direction sensing I'm talking about the heading hold component.

A good example of this is the tail. If you switch the model on in the pits with the nose of the model pointing left. You the walk out to the flight line and put the model on the ground pointing away from you. The gyro will be trying to make the model point to where it was where you switched it on.

By using the stick to centre the pitch slider you cancel the effect.

Now obviously this is an over simplified version of what happens the gyro will only try to return so far typically less than 45degs and the same is true for the cyclics on a fbl. But as you switch it on sitting upright the error is more likely to be from you moving the sticks my accident on the walk out.

This is something I do in the first couple of seconds after starting to raise the throttle and is a preflight as I'm still on the ground 😀


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