vertical tail fin stabiliser

[rob12770]

Hi i notice a few chunks out my vertical tail fin stabiliser on my trex 450 after flying it for the first time..
i think this was caused by it sort of sticking in the grass and being pulled towards the tail rotors.. is there any way i can resolve this ? can i cut a little off the bottom but enough to still leave it long enough to work as an anti tail strike device ?

i notice i had to pitch forward a little when taking off to clear the grass at the tail....
cheers

[tomatwalden]

Buy a new tail fin! They're only a few quid ...

[Boggy]

I think Rob is saying its too long and flexible Tom.

Yes trim it down but leave it longer than the tail blades job done

[rob12770]

Buy a new tail fin! They're only a few quid ...

LOL yes mate, its not the money .. its the overall issue of it getting caught

[rob12770]

I think Rob is saying its too long and flexible Tom.

Yes trim it down but leave it longer than the tail blades job done

OK , thanks , i just thought id check it was cool to do that ,,
i guess im lucky it didnt damage my tail rotor blades.. or worse..

[Granpappy]

I've just had a look at your 1st flight video again. You did plonk it down quite hard a couple of times. I wouldn't trim the vertical fin otherwise you will end up with the tail blades hitting the ground. The fins are normally quite stiff so if it flexes too much then it is probably de-laminated and needs replacing. I always make the vertical fin a bit longer to protect the blades and gears.

When you land the heli, just go up to it and reposition it on the ground before you take off again. That way you know that the fin won't get caught and is not dug in to the ground. Simples.

[rob12770]

I've just had a look at your 1st flight video again. You did plonk it down quite hard a couple of times. I wouldn't trim the vertical fin otherwise you will end up with the tail blades hitting the ground. The fins are normally quite stiff so if it flexes too much then it is probably de-laminated and needs replacing. I always make the vertical fin a bit longer to protect the blades and gears.

When you land the heli, just go up to it and reposition it on the ground before you take off again. That way you know that the fin won't get caught and is not dug in to the ground. Simples.

So.. your saying pilot error ???
Damn i thought i was a Pro !! guess i should cancel my interview for the coastguard

OK, Thanks mate for the Advice, it Is Much appreciated
cheers rob

[Granpappy]

So.. your saying pilot error ???
Damn i thought i was a Pro !! guess i should cancel my interview for the coastguard

OK, Thanks mate Advice, it Is Much appreciated
cheers rob

You will get there. You did about ten times better than I did on my first flight.

[tomatwalden]

LOL yes mate, its not the money .. its the overall issue of it getting caught

Ah. I see! To be honest, I sort of agree with GranPappy. If you're bending the tail fin that much on a 450 such that it goes anywhere near the tail blades, you're doing it wrong!

I personally would not advise shortening the fin - it's the length it is for a reason! I haven't seen the video mentioned, but it sounds like you need to work a bit on your take off and landing technique!

[rob12770]

well yeah, ive just started to learn..
but joined the forum a long time ago..

[tomatwalden]

Not criticising at all ... we've all been there. My first few flights with a 450 were borderline horrific when I look back on them (some on youtube for posterity!)

You may want to consider a plastic fin though? They're cheaper and sometimes more flexible than their CF counterparts.

[rob12770]

i have the plastic one mate, like you say, i just need to practice..its all a bit trial and error, and i am not getting any younger so i thought id have a bash..i like to tinker too
link to that video here http://www.rcheliaddict.co.uk/beginn...ght-450-a.html
cheers

[tomatwalden]

OK, some landings do look a little harsh. What pitch curve do you have? Standard advice for beginners is to run a shallow pitch curve that gives very little negative pitch - just enough to allow you to bring the heli down gently. This means that in panic moments, the normal reaction to "drop the throttle" doesn't result in loads of negative pitch forcing the heli into the ground. Something like 30,40,50,75,100 (assuming 50=mid stick, zero degrees).

[rob12770]

OK, im not too clued up on the technical side but i set my pitch curve to ( norm) 44 52 74 84 93 .. does that sound ok ?
cheers

[tomatwalden]

Er. no, not to my mind .... Those numbers mean this with regards to the position of the left (throttle/collective) stick. Bearing in mind that 50 = mid-stick.

LOW : 44 = very slightly negative pitch with no power to motor
1/4 :52 = at only quarter stick, the blades have already started to introduce positive pitch (ie. lift)
MID : 74 = at mid-stick, the blades have roughly 6deg angle of attack.
3/4 : 84 = at three-quarters stick, the blades have roughly 8deg angle to attack
HIGH : 93 = at the top, you have about 10deg angle of attack.

You should be aiming to maintain a hover at just above mid-stick, hence the numbers I suggested before ... 30,40,50,75,100

Notice that the middle number (mid-stick) is ZERO degrees (50% travel from full negative to full positive). So, the heli only starts to lift once the left stick has passed the mid-point.

Whilst we're on it, what does your throttle curve look like too?