4 Blade tail rotor

[antsis]

Ok chaps - bit the bullet & ordered the 3 blade tail.
This is going to be the full-blown scale project now.
5 blade head + 3 blade tail
Scorpion 2221-12 + Commander 45A ESC
Align 3G

Question is......will it fly?
I'll let you know.

Thanks for the input
Keith

If you are going for the full scale effect, then you need to fit either a 2 blade tail (older 500D/E models) or the 4 blade tail which is an option on the 530F. None of the Hughes/MD helicopters flew with a 3 blade tail.

However, as you are fitting it to improve the tail authority, give it a go. It will not be noticed when flying.

[RotorBlade]

Well - to update, the 3 blade tail arrived this morning and will not fit the Trex 450 Pro tail, which is a real shame as it's a great looking piece of equipment.
Obviously, the Heliartist is for a belt, but I was hoping that the blade assembly would fit the shaft of the TT.
It doesn't even come close. Not only does the shaft attach to the tail case differently (so it cannot be swapped completely), but the TT shaft is 4mm shorter and the geometry of the slider control mount is offset on the Align and central on the Heliartist.

Just thought it was worth noting in case anyone else thinks of trying it.

So, back to the full scale 2 or 4 blade idea.
Ho hum

[Si Goodchild]

Bad luck on the tail, mate. One for eBay, I guess.

A lot of new things going on there at the same time - new airframe (to you), new head, FBL, new drive train (4s).

You might want to think about flying this thing incrementally e.g. fly it stock on 3s to start with, then swap out the drive train then add the head and FBL system in one go. You can use the 3G unit as just a gyro IIRC, so if you sort that out early doors, you won't have to worry about the tail when you get the full FBL functions running. Just my 2p worth, it's more work, but should de-risk the project as you go. Good call on going 4s with that setup, that should be a strong motor and you have some good batts already (and can borrow a couple of my 45-90c nano techs if you like) but you will need a new pinion as the stock one has a 3.5mm hole IIRC, whereas the Scorpion motor has a 3.17mm shaft. That's a good thing, though - loads of scope for experimenting with the right pinion size for your head speed.

Si

[RotorBlade]

FL issuing refund as the unit is untouched (just measured it) - Nice!

Good suggestions mate - I was intending to fly pod & boom first, but as I've got no 450 sized blades except the scalers at 315mm, I can't try the stock head, which I butchered for the link balls anyway. The 5 blade should be ok with the 430 motor/stock esc to get the tail geometry set up.
This looks like a handy 4 blade project at some point if I can't get it to hold.....

MD 500D (450 Size) Scale RotorHead And NEW Cascade Tail - YouTube

Those 4s of mine have never been overworked eh??

Keith

[Si Goodchild]

I'm sure that a pair of the 315mm blades will be fine on the stock head. How much did you "butcher" it? You're welcome to take bits as required from my "box of many things" if you can get the standard head up and running. The benefit of this is that you don't need to get the FBL unit running properly from the off and you can check everything out. No biggie if you don't want to tho'.

We need to do the maths on your pinion choice. I wonder what the guys think here about a target head speed: low, I hope.

[RotorBlade]

Reading the 'Freak' it seems the problem always comes down to tail control. The 2221-12 with an 11 tooth looks about best, but that will give issues with tail authority. I have ordered a pack of link-balls and some McpX main rotor blades, which some say can be cut down to a good size to counter the 5 blade torque. The balls will be enough for me to re-set the stock head, but those 315mm blades are the scale ones - mighty thin.

Assuming an 11t pinion and 80% efficiency, if I am right, headspeed with a 4s 14.8v battery should be....

(2580kv x 14.8v) / (150 / 11) x 80% = 2240 rpm

How does that sound??
Keith

PS
Need to change Ken's 50 pikkie LOL

[Chris Boughton]

Reading the 'Freak' it seems the problem always comes down to tail control. The 2221-12 with an 11 tooth looks about best, but that will give issues with tail authority. I have ordered a pack of link-balls and some McpX main rotor blades, which some say can be cut down to a good size to counter the 5 blade torque. The balls will be enough for me to re-set the stock head, but those 315mm blades are the scale ones - mighty thin.

Assuming an 11t pinion and 80% efficiency, if I am right, headspeed with a 4s 14.8v battery should be....

(2580kv x 14.8v) / (150 / 11) x 80% = 2240 rpm

How does that sound??
Keith

PS
Need to change Ken's 50 pikkie LOL

Yep that is exactly right i checked it on my headspeed calulator and it came out at 2240rpm at 80% efficiency and 85% is 2380rpm!!! Unlucky about the three blade tail u just need to find a longet tail out put shaft!!!!

[RotorBlade]

Yep that is exactly right i checked it on my headspeed calulator and it came out at 2240rpm at 80% efficiency and 85% is 2380rpm!!! Unlucky about the three blade tail u just need to find a longet tail out put shaft!!!!

Thanks for that.

Nope - it's worse than that Chris. The slider control arm on the Align unit is offset from the centre and the slider itself is a single arm. On the Heliartist unit, the slider is connected by 2 parallel arms that each bolt to 2 equally spaced mounts on the tail case, if that makes sense. I even thought whether the Align arm could sit between those two mounts and size-wise it would, but then the geometry was all wrong.
What a pain! Hopefully, longer tails might solve it and the McpX blades at £6 per pop won't exactly break the bank!

Keith

[nitromad]

+1 for sportsmoto i have a DEAO x4 bld on my AH64 Apache, Quick also do tail rotor hubs

[ATTACH=CONFIG]33282[/ATTACH][ATTACH=CONFIG]33283[/ATTACH][ATTACH=CONFIG]33284[/ATTACH][ATTACH=CONFIG]33285[/ATTACH][ATTACH=CONFIG]33286[/ATTACH] Yes it is a real scale trex 500 heli artist body, i modified the tail to l/h output. also fitted nav lights + anti colision strobe looks Evil at night!

cheers
cuppa

cuppa u got more pics ? i love to see that more/better

[Nordica155]

It is best to fit a multi tail rotor with scale multi heads. You could try longer tail blades but the torque increase from minute pitch increases on the main blades will cause holding issues. With multi mains you can afford to reduce angle of attack with higher head speed or lower the head speed and pitch greater, blade inertia and Nr decay will then be an issue, as well as tail authority if you only have 2 blades.It's a balancing act but with rotary wings the blade surface area of both main and tails must be matched, more main blades more tail blades. There is also the blade length and camber to take into effect.....it goes on to be honest. Just like I have.

[dannyhough]

I have a MD500e 450 Pro with CX 5 blade head and HA 4 blade tail on TT and had no worries getting it sorted on the standard TT output shaft. In fact sounds almost identical to the heli i have. You certainly need a multiblade tail with the 5 blade head as the 2 blader provides 0 tail authority.

Here's a link to the build thread,
HA Hughes 500E - Heliguy.com

as you will see it went through a few phases :0 bottom of page 1 is the 4 blade tail, just read it and then looked at the heli and FYI the tail shaft is 4.5mm inside the rotor hub but secure and has around 200 flights this way without issue. Just make sure to use threadlock

[RotorBlade]

Thanks for the info Dan - a great thread & build!
Where did you get your 4 blade tail from?
Also, how did you fix the frame to the spacers - the pro has just the one central skid fixing.
Thanks bud
Keith

[dannyhough]

No worries Keith, yeah i enjoyed getting that one in the air As for securing, after much chin scratching and thread reading i ended up using cable ties (sure it's in the build thread somewhere) one around the base ply and frame right under the main shaft and one either side at the front.

Pulled tight as poss with pliers and a neoprene pad between the frame and the ply to stop slipping. Works a treat!

[RotorBlade]

What about the 4 blade tail Dan??

[dannyhough]

Oooops sorry! It's the Heli Artist one that's on there, tried a cheapy from fleebay but it was gash If you got the genuine HA one from Flying Hobby then give it a whirl mate should be fine.