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HIROBO Freya - Sceadu - Shuttle > Freya Tail Chinese Weights
 
 
LeifElite Veteran - Location: Oxford, PA - USA -
I found an inexpensive and not-too-difficult way to make Chinese weights for the Freya tail that I'm running on my Evo 50.

The actual weights are a set of four link balls and M2x8 bolts.

You'll need some spacers since the 8mm bolts are a bit long. I made my own spacers using a bit of plastic from a crashed servo frame.

Drill holes in the plastic and cut it into small squares.

Thread the squares on a spare M2 bolt.

Sand down to a nice round shape.

The spacers are a bit thick. I put a bit of a counter-sink on one side to let the ball sit a bit into the spacer.

The bolt is just the right length. You don't want it long enough to touch the shaft.

Locate the plastic spacer in the grip that separates the thrust bearing from the inner radial bearing. Drill exactly in the middle of this spacer using a 1/16" drill bit.

Note location of the finished hole. Do all four grip halves.

I sanded down the lettering a bit to allow the spacer to sit flush against the grip.

Use CA when screwing in the bolts. This and the tight fit hold the weights very securely.

All weights installed.

Assemble the grips on the tail hub. The finished product looks like this.

I had to dial down my gyro gain by a VERY large amount to keep the tail from hunting, but it holds like a rock in tailslides and the piro speed is blindingly fast with MAH 90mm blades.

Leif
05-29-2008 02:16 AM
 
 
Ivan
Veteran
Location: Hutchinson Kansas

I have thought of doing this myself. While rebuilding my tail on the freya, I used the belt to give the tail assembly a spin, and even at low rpms (3000 maybe) the amount of centering force was amazing. I can imagine what it would be like at 10k.

I appreciate your ingenuity, I have been scratching my head on this for a few days.

Do you think two weights per grip are necessary? or could you just use one? I know the theory on this, but since the grip cant rotate the full 360, it would seem that one weight would suffice.

I came, I saw, I hovered
05-29-2008 02:38 PM
HOMEPAGE  
 
 
Jafa
Elite Veteran
Location: Sydney, Australia

That's really cool - well done

Should make the tail servo last longer
and stop better also


Lepton | TRex600Nitro | Sceadu | Freya | Avant | Predator Carbon Max
05-29-2008 02:47 PM
 
 
Leif
Elite Veteran
Location: Oxford, PA - USA

Quote 
Do you think two weights per grip are necessary? or could you just use one? I know the theory on this, but since the grip cant rotate the full 360, it would seem that one weight would suffice.

In theory, you could probably use one weight instead of two. However, this would introduce unequal loading on the bearings in the tail. I initially experimented with a number of different combinations, from a single ex ball to one regular and one EX ball. The single standard ball seemed to be the best combination. The idea is to keep the weight as low as possible by putting the weights further from the axis center. A very long bolt with an EX ball would probably do the same thing, but I would be worried that the weight might catch on something.

Leif
05-29-2008 02:55 PM
 
 
Helijost
Senior Heliman
Location: Pevely, MO - USA

Looks cool. Dumb question, what parts are you using for the Freya tail? I've been wanting to change to it on my Evo 50.

700N, EVO 50, Caliber 5, Beam 450, and comming soon TREX 9000 :)
05-29-2008 03:11 PM
HOMEPAGE  
 
 
Brian Bennett
Key Veteran
Location: Dugway/Tooele UT, USA

You need the tail grips, hub and in addition to the Evo 50 thrust bearings a second set of thrust bearings which are a slightly different thickness. I don't have the part numbers in reach but someone here does. I like the 90 tail on the 50 alot.

B

Team MRC-Hirobo and Model Avionics Rep
05-29-2008 03:47 PM
HOMEPAGE  
 
 
Ivan
Veteran
Location: Hutchinson Kansas

I would guess that the sngle ball in stock config gives an unequal loading on the bearings.

I also remember something about weights closer to the hub center being more effective. All in all your setup works like a charm, and beats all the ideas I had.

I came, I saw, I hovered
05-29-2008 06:36 PM
HOMEPAGE  
 
 
Leif
Elite Veteran
Location: Oxford, PA - USA

Here are the parts needed for the Freya Tail upgrade on the Evo 50.

0414-164 Freya Tail Rotor Hub
0404-662 Freya Tail Grips
2500-070 3x9x3 Bearings
2506-003 M3x6mmx0.5mm Washers
2532-028 M2x8 Screws

You'll re-use the existing radial bearings and thrust bearings from the Evo 50 tail. You can also re-use the M2x8 screws that hold the grips together (although I included the part number for these as well). In addition to the grips and hub, you need the extra radial bearing set and some M3x6x0.5mm washers.

It's a really easy upgrade. You actually get the instruction sheet for the Freya tail with the grips. That's the sheet in the background in the above pictures.

With the Freya tail, you'll want to stick with tail blades no longer than 92mm. I like the MAH 90mm blades that come with the US kits, but I've also run stock Freya plastic 92mm blades. Anything longer and you risk hitting the ground with the tail. The Freya tail is 17mm wider diameter (bolt to bolt) compared to the Evo 50 tail, so you don't need as long tail blades for the same disc size.

Leif
05-29-2008 07:07 PM
 
 
Helijost
Senior Heliman
Location: Pevely, MO - USA

Thanks Leif! I have already ordered those parts.

700N, EVO 50, Caliber 5, Beam 450, and comming soon TREX 9000 :)
05-30-2008 12:53 PM
HOMEPAGE  
 
 
Turkana
Senior Heliman
Location: Montreal,Quebec , Canada

Hi
Yes I also had great results with chinese weights on my T rex 450 and on my Evo 50.I had a slightly diffrent approach.Check out the foto.You actually only have to use a longer bold on the Tailblade, has the same result.

05-31-2008 07:27 PM
 
 
Ivan
Veteran
Location: Hutchinson Kansas

I just perfomed the same procedure as Lief, but I found some linkage balls from the LHS from a blade 400. they are tailor made for the job. I cant figure how to post a photo from my phone, otherwise I would.

Eflite part#: EFLH1435 (Control/Linkage Ball, Long (4): B400)

I came, I saw, I hovered
06-01-2008 03:28 PM
HOMEPAGE  
 
 
Juggy
Senior Heliman
Location: Pomona, CA-USA

the freya already have the superior hold on tail. why bother to change it. why not just learn to fly better. and u really think that the freya is not heavy enough?

Fly the way i want => IRON NUT
06-01-2008 05:44 PM
HOMEPAGE  
 
 
clive45
Veteran
Location: NSW Australia

I think the idea is to take the pressure off the tail servo as they do in full size helis, why make things work harder than they need to. It will also lower current drain on the battery.

He who dies with the most toys is none the less DEAD
06-02-2008 12:04 AM
 
 
Turkana
Senior Heliman
Location: Montreal,Quebec , Canada

Very true.You can take up the gain on the Gyro too. Full size helis use the same weights.
06-02-2008 02:41 AM
 
 
Ivan
Veteran
Location: Hutchinson Kansas

Juggy, were talking about adding a quarter of an ounce in weight. You would be surprised at how much centering force the ball puts in the tail system. I flew mine with the weights today and the control response improvement was highly noticable. I was able to do some high speed backward circuits with out the tail blowing out, which wasnt possible before.

I also got PM'd about Gforce grips that have the weights machined into them. Too bad my heli's life expectancy is less than that of the last gas price "plateau"

I came, I saw, I hovered
06-02-2008 06:05 AM
HOMEPAGE  
 
 
Leif
Elite Veteran
Location: Oxford, PA - USA

The purpose of the weights isn't necessarily to improve the tail performance. The Freya tail on the Evo 50 is already so overpowered that no improvement is required.

The reason for the modification is to reduce the load on the tail servo. This increases the servo performance (makes it react faster), reduces the current draw on the batteries and makes the tail servo last longer.

The increased holding power at low gyro gain is a plus. Being able to get reliable high-speed backwards flight with a GY401 is another.

Leif
06-02-2008 05:02 PM
 
 
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HIROBO Freya - Sceadu - Shuttle > Freya Tail Chinese Weights
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