Stretching your T-500 into a T-550 for scale use - RC Groups
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Apr 15, 2012, 09:56 PM
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cap231ex's Avatar
Build Log

Stretching your T-500 into a T-550 for scale use

I just started the new build of my HK-500GT stretched into a 550 to be installed at a later time in a .30 size scale fuselage.

Sideways LS4 did this first and has helped me with my build greatly , many thanks to my friend Sideways LS4.

You need to source a couple items.

Belt = Gates MXL 681

Tailboom tube = 6061 T6 Aluminum tubing O.D. 0.625" x wall 0.035" x I.D. 0.555" x 24" in length

A 550 head , I used the Gaui stock plastic one for the Gaui 425 / 550 and Sideways used a combination of the Gaui metal head and CNC Helicopter parts.
But as long as you use a head with grips that will accept 12mm blade roots and a 8mm main shaft you will be in fine shape.

I started off fabing the tailboom and getting it all fixed up as I waited for parts to start being delivered.
I started by getting a straight line drawn on the tailboom stock with straightedge and sharpie.
I then taped the stock boom to the new tailboom stock to mark the front notch that goes into the boom mount. Then drill the back rounded end and cut the notch out with your dremel tool.
Next because I plan on running a very low headspeed ( hoping something around 1200-1250) I replaced the stock 19t tailrotor pulley with a HC-500 13t pulley.

I then measured to cut the boom to length by installin it on the front drive and the tailrotor gearbox and pulling it tight while measuring.
Then cut the tubing cleaned the inside and marked the hole for the tailrotor gearbox ad installed the boom to make sure it fit correctly.

Finally I sprayed a lite coat of gloss black on it to dress it up a bit and installed the finishing bits and pieces as you would normally.

This is where I'm at right now till I get more parts in to complete the project , enjoy the pics.
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Apr 15, 2012, 10:38 PM
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crazhorse's Avatar
Good info, I'm wanting to do a .30 jet ranger........ I ordered a Gaui 425 and all the items needed to stretch it to a 550. When I got it in was shocked at how big around the tailboom is, unsure as to whether it will fit in a funkey jr fuse. May end up getting another 500 and following your build.
Apr 16, 2012, 02:58 AM
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BigGuyJT's Avatar
I have a .30 Augusta a109 i was going to put on an hk 600 with the 550 boom. Length was great but the swash is too big for the opening. Is the 550 swash you are using any smaller?
Apr 16, 2012, 11:50 AM
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cap231ex's Avatar
BigGuyJT I am not using a 550 swash , this is a 500 stretched to a 550.

Yes the Gaui 425 is actually using a shortened down version of a T-600 dia. boom , and the belt width is the same as a 600.
Maybe that would be a good candidate for stretching into a 600?
Apr 16, 2012, 03:27 PM
Redjestird Youser
SidewaysLS4's Avatar
Good to see some more 'supersized' T500's

A couple notes: I started with a Gaui FES head (aluminum) on mine, along with a Gaui X5 flybar main shaft/custom one-way bearing hub for added main rotor height. The Gaui FES head hub has a somewhat poor fit on the main shaft. Going with the aftermarket/clone CNC Heli hub linked in Cap's post makes for a better fit (and less vibes too). Note that you need to order the shims Cap linked also as the damper setup is different than Gaui if you are going to use this hub.

The Hobbyking 30x25mm 850kv motor that they sell for maybe $16.00 isnt the best deal...lots of vibes coming out of that (even after you remove the 'fan' portion of it, as that is very visibly drilled off-center). IMO is better to spend more $ initally on a better quality motor to get the headspeeds down to .30 size levels. Currently I'm using a Scorp 3026 880kv motor...lots quieter and smoother than the screechy and vibey HK motor.

Other than these two items...pretty smooth conversion. Really cuts down the weight on these .30 size .30 Funkey Jetranger weighs in at 6lbs running a 6S 3000mah battery . The mechanics themselves better match the scale also...I was using Trex before on my .30 scaler...overkill IMO, lol.

Here's some test hop videos of my stretch (somewhat noisy as these videos were shot with that HK motor on board)...

Overgrown T500 with 550mm blades.wmv (2 min 29 sec)

T500 30 Jet Ranger.wmv (1 min 45 sec)
Apr 16, 2012, 04:01 PM
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cap231ex's Avatar
Thanks for the added info Sideways.

Yeah the HK motor has a very hi-pitched screech to it.

Got my motor , ESC , and HW program box to day working on getting them installed on the airframe , pics to come later.
Apr 16, 2012, 10:31 PM
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crazhorse's Avatar
So the regular FES head for the 550 would of sat too low ? Wondering because I have one on the way from aircraft world... heck of a deal on the whole conversion to flybarless, comes with the head, follower and the flybarless controller for 89 bucks plus shipping, when what I found stateside the cheapest was the fes head and follower for 99 plus shipping. Unsure whether I'll use the controller that came with the package, was either planning to use a cx unit or scrounging the for sale sections for a skookum 360, or waiting for the 520 to come out.
So what I gather Cap the gaui tailboom is too big as in diameter, I know you can go either 500 or 550 length wise for the 30 size jetranger fuse ? Bummer if it is, as I already have a blackhawk fuse for it.........
Apr 18, 2012, 11:10 AM
Redjestird Youser
SidewaysLS4's Avatar
The 1:1 Jetranger has a fairly high main rotor height, so I tried to get it as high as possible using the Gaui shaft. Note that to do this, you need to find a way to get the autorotation gear to accept a 8mm wide main shaft with no step like the Align main shaft. This is done by digging up from somewhere an origional HK500 autorotation bearing hub that is out of spec with the Align design but allows a non-stepped 8mm main shaft to be used. (thanks Cap for that part! )
Apr 20, 2012, 12:50 PM
Composite factory
Dear Sideways
I want to make small size fuselage in coming future , is it 550 better that 500 size . or in the future the new 550 size will represent the market 500 size . because the power set and equipment almost very similar !

Apr 20, 2012, 09:51 PM
My hobby is why Im broke
darthdrk's Avatar
Hmmm Kin no want a piece of the pie, kin want all of the pie. Well if you gonna do it you may as well go all the way
Apr 21, 2012, 03:33 AM
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cap231ex's Avatar
Like I told you Ed the 550 size in scale is quickly becoming more and more popular the only problem is only Century / Fun-Key is making the 30 size or 550 size fuselages.

If Kin wants to start producing them and can produce a product equal to or better than the Fun-Key fuselages at about or less then their price , I would say he will do very well with that size.

He is on the right track in selling and thinking global and producing the mass quanities , that's the only way you can make them affordable and yet still make money yourself.
Apr 21, 2012, 05:18 AM
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grover's Avatar
And if he can get " hobby king " to make a 550 . He would have the world at his feet .
A cheep Heli in a top class scale fuselage . Go for it Kin ...

O yes nice work Cap231ex
Apr 28, 2012, 10:57 PM
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cap231ex's Avatar
Got the 550 pretty much built , ended up installing Power HD digital HD-3688HB servos on the cyclic and a Futaba S9257 on the tail.
A Tarot ZYX 3 axis FBL unit , a Hobbywing Platinum 80amp ESC , a Moxie AX-3026 880Kv motor and running it off a 3000mah 6s 20C battery.

I ended up replacing the main gear with an Align helical 134t main and an 11t pinion and an Align tail slider and slider arm on the tail.

Other then those and the head and tail boom stretch it is a stock HK 500.

It flies great I still need to tune on it a little to tune out a small tail wag I had the first couple times I've flown it.
Hoping the weather will straighten up and the wind will let up a littl to get it and my stretched 700 to the field and shot some video of both.
May 10, 2012, 11:50 AM
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Ask and you shall receive!
May 10, 2012, 12:39 PM
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cap231ex's Avatar
That's nice but still it is nothing more then a down sized 600 and trying to fit it in a 30 size fuselage is like trying to fit a woman with a size 10 foot in a pair of size 8 heels. With plenty of lube and force yeah it can happen but it is far from looking like it belongs plus this makes a much liter weight 550 at a fraction of the price of that 550 (under $100.00 total for the airframe).

But thanks for adding it.

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