Hurricane 425 build log

[stark]

Hi,

I finally decided to build the Hurricane 425 so that I can use it as my trainer heli.
I'll be posting pictures and notes of the build in this thread along with questions. I hope that it will benefit anyone intending to build the 425.

PART LIST:

• Gaui 425 basic kit - G-204399
  (Kit comes with 50T main gear, 19T One way gear and 61T Rear main gear)
• 425mm CF mail blades
• Motor - Compass Atom 500 motor 1050kv
• 16T pinion - G-901601
• 42T main gear - G-204021
• ESC - Turnigy K-force 100A
  
• Cyclic Servos - 3 x Hyperion HP-DS20-FMD
• Tail Servo - Hyperion HP-DS20X-GCD
  
• Gyro - Spartan Quark
  
• Turnigy 6S 3000mAh 30C battery pack
  
• Hitec Aurora 9 Radio system with 6-ch receiver.

With 1050kv motor, 16T pinion and 42T main gear I should get a max. head speed of 2766rpm.

(22.2 x 1050) / ( (61/19) x (42/16) ) = 2766

Please let me know if I should change anything in my part list.


Based on inputs from users I would need the following items:

Tail servo mount : G-204710
Tail push rod adjuster : G-204660 or G-204661.

These parts will allow me to mount the tail servo on the boom to have better COG as my battery pack weighs 500g.

The compass motor diameter is about 48mm and would bind with the frame and roll/pitch bell crank arms. To fix this I would need larger main gear and larger pinion to maintain ~2600 rpm. I might also need some spacers to push the roll/pitch bell cranks further out of the frame.

60T main gear: G-204622
22T 32P (0.8 mod) motor pinion: Castle Creations 22T 32P Pinion Gear or Robinson RRPC8722


K-force 100A was out of stock so I went ahead with

Hobbywing Platinum Pro 80A
Hobbywing 2 in 1 Advannced Professional program box - for updating ESC firmware


cheers,

[stark]

Everything was well packed and the parts have decent quality. Good value for money.

[sp00fman]

Nice list. Good electronics, looks like high end gear.

A thing i noticed on my 425: it tends to be nose heavy. I got 2x2800mah 30C (230g each) to try out and I had to boom-mount my tail servo to get CoG correct. Also note a 20C lipo wont cut it. my 2x 2200mAh 20C packs i test hovered with got too hot for comfort, and lasted only 3 minutes or so. The packs are a bit older, but it does give an impression.

[stark]

Thanks for the tip sp00fman.

What part# did you use to boom mount the tail servo? I don't think it comes with the basic kit.

My battery pack weighs 500g which would be close to your setup, so I suspect it will be nose heavy until I stretch it to a 550. I want to keep it as a 425 till I'm comfortable enough and don't crash so often.
The battery is 30C so I expect it to run cooler.

One more thing I observed is that the compass motor has large diameter (48mm) just like the Scorpion 4020. This means that I have to either go with larger main gear and pinion so that the motor does not touch the roll bell cranks/frame OR go for a smaller diameter motor.

How does the 60T main gear and 22T pinion combination go?

[sp00fman]

The 425mm blades are a LOT cheaper than 500mm+. I got two pairs of carbon "pro 3D" for just $26 +added shipping weight. I won't be stretching until there is a 500mm or 520mm with a decent price. A little mishap costing me a $50 blade set is just out of my league right now.

I dont see why a bigger pinion would be a problem. Gaui wont have one for you so you need to get one from an electric car/buggy. With the motor further forward the CoG problem will be worse.
If the motor clears the frame you could mount the bellcrank on the frame with a spacer in between to clear the motor.

Here is the boom mount i used link or link .It looks pretty bulky on there, but is in the gaui style. You could also get a trex500 mount (same boom diameter) and get a full size servo holder on there from the trex600 tail mount part.
I got the extended link set with adjuster from gaui and cut the rod to the correct size so my servo is pretty far back. link.

Look here if you want to see how it worked out on my heli. I did move the servo further back later on.

[Mikej]

Unfortunately that is the biggest down-side of the 550 stretch - blades can be had for just over $30 http://www.ebay.com/itm/550mm-Glass-...item2313e5eddc or $36 for CF http://www.ebay.com/itm/New-Carbon-F...item2a0d75ad9b . I'm still waiting for the Trex 550 to drive costs of the 520mm / 550mm blades, but it hasn't happened yet

[stark]

sp00fman,

Your heli looks neat. What canopy you used?
Why is your signature "flying 450 clone", don't you like your hurricane?

I've updated my original partlist with the parts you suggested. Thanks.

What spacers do you use to bring out the roll/pitch bell cranks? I was thinking of getting a set of B3x6x2.5 bearings. gaui part# 204560

[stark]

Was freaking cold today here. -20 C
Enjoy the pic without the cold .

[sp00fman]

Decent price on the 550 mm blades, but i dont want 550, im just like you waiting for the cheap 500-520mm blades to come out.

--

It's the 2 halves canopy that came with the plastic kit. I took my time on it and went for a clean design i borrowed from another member here.
I did not used spacers myself. I've read someone using flybar weights as spacers on that spot.
Anything with the right ID will do as long as you dont bind up the bearing's OD.

My hurricane is the ultimate underground shelve queen at the moment. I love it but have not flown it yet with the new servo's and bigger lipo's installed. I just need to do the CCPM setup and its done.... i felt i was waiting for something...... and faith showed my i was. my trex 450 clones recently went FBL and they they just fly straight now and is giving me a huge boost in confidence and my flying skills seem to advance again. With the sloppy flybarred setup they were all over the place and i dont want my Hurri to be my trainer/beater heli. I want it to stay nice. My 450 sized flying field is 200 meters away... people are walking around it, sometimes kids and dogs, so flying a 500 sized heli like this

450 FBL daytime flight (5 min 0 sec)

would be very irresponsible. Its to cold to get out to the bigger field carrying one suitable lipo pack

and besides....my hurri is still under a table hidden from the wife-radar. When i finish school this summer its gonna magically appear under the very early Christmas tree, and I'll have all the time to enjoy it and think the wife will be ok if i give here something nice for her support she gave me (AKA, bribe her) .


edit: i just wanted a link to youtube, not a hole frame. silly forum...

[stark]

Originally Posted by sp00fman

It's the 2 halves canopy that came with the plastic kit.

Not bad at all for that flexi plastic . Any pointers how to paint it. I've never done any paint job, but would love to.

Originally Posted by sp00fman

and besides....my hurri is still under a table hidden from the wife-radar. When i finish school this summer its gonna magically appear under the very early Christmas tree, and I'll have all the time to enjoy it and think the wife will be ok if i give here something nice for her support she gave me (AKA, bribe her) .

Couldn't stop smiling after reading this

[sp00fman]

How to paint? Buy rattle cans and start to practice. I had a few plastic "milk jug type" 450 canopies for 80cents a pop. I put this design on that first to see how it is to fly it and how the two colors mixed. Stay with the same brand paint!!!!

To my hurri canopy: take your time to cut it out and start gluing from the nose first.. Do small potions at a time and let cure in between with pressure on (watched movie while pressing my thumbs on it). I made strips from the excess and reinforced the seem from the inside.
Fill up the seem, sand smooth with fine sandpaper. Start with the light color. Spray a light coat, let dry for a few minutes, repeat until nice. Mask with tape you know will seal but not ripp off your paint, spray darker color in a few layers. Remove masking tape when still slightly wet. Let cure completely and add ~5 layers of automotive high gloss clear coat you know wont bubble or eat up you paint.. It ended up not so shiny with me so the last layer of clear i put on was from very up close and a thick layer, just not starting to drip. that gave it its gloss. Finished off the not so nice edge between the colors with a roll of aluminum like reflective tape from a "home depot" store. (department floors)
Finally gave it a nice wax with carwax (main blades also)


Alternative is: grab CC and buy a nice canopy online

[stark]

Thanks sp00fman, for the painting instructions. It sure looks like a lot of work.

[stark]

Some more pics of the build

Identifying the frame bearings


Placed them in one of the frames. Bearings #D can be put later after joining the frame but before tightening all frame screws.


Main gear, one way gear, and tail drive gears.


Fit the front main gear and one way gear.


Fit the tail front pulley and gear.


Time for the spindle and rear main gear.


The above assembly won't go in the frame in one piece. You will have to place the gear in the frame and feed the spindle from top.
Tightened the mast collar with thread lock.

[stark]

Too bad k-force 100A has gone out of stock on hobbyking. I might settle for Hobbywing 60A Platinum pro instead. 60A should be enough for this bird i suppose.

Do I need to use separate BEC? the ESC has 3A switching BEC already.

[stark]

sp00fman, nice flying there. You are already doing inverted flips, loops and rolls. What are you waiting for? I seriously think you should move to a bigger heli and fly at a bigger n safer field.

[PTcaflyer]

Hobby Wing Platinum Pro is the same as the HK ESC...I use the 80a on my 550 and the 100a on my mid boom 500 !
...NO seperate BEC needed IMHO....
PT

[sp00fman]

All in due time. next flight on the hurri will also be recored and posted for sure.

I got a hobbywing 60amp speed control (same as Plush 60A) and it might be a bit marginal. Motor ,auto-rotation shaft and ESC got quite hot with just hovering. I still need to troubleshoot the cause (either crap motor, bad motor timings, binding somewhere, or friction in a bearing)
I hope i dont need to re-buy my motor and ESC combo in time.

You could just backorder that ESC. ive seen it restocked reguarly (its still on my wish-list)
There is also a 70amp HV version of that ESC. 105A burst.

[Jerrymac]

A little tip on the milk jug canopy. Cut 3 small pieces of the 'extra' plastic and CA it inside at all 3 of the canopy mounting points before drilling the holes. The double layer helps keep it from cracking at the mounts.

[stark]

Where is the 3rd canopy mounting point and how is it mounted? I can't figure it out from the manual. Pictures would help.

For the ESC, the 70A HV does not come with BEC. I don't intend to run the bird on more than 6S, so the 80A Platinum pro ESC seems like a better option at the moment.

[PTcaflyer]

...The Third, of which I will call the "Lower Mount", is placed on top of the front landing gear skid and the plastic pin is at the front...some peeps point them up, but I point mine down so that the canopy locks into it first and then will roll up onto the upper mounts...
IF YOU FIND you need to put a larger canopy on it...to run larger Batts, just make a new, longer one from a large servo arm...I have done this on my 550 to be able to run 3000mAH batts and sometimes fly with a modified Align 550E canopy (see my albums)
PT