Trex 450 S-76C Build Log

[majuro15]

Trex 450 S-76C Build Log

I’m starting my second scale build adding to my Bell 222 on a 450 this week. I have been waiting for Darth to complete this fuselage for about six months (thanks for getting it done!) and so far, I think I am the first to post on it.

So I have big plans for this little heli and the build will be quite time consuming. I’m really going to try to keep up with the log on here though because so many others have had awesome threads going!

Here is the kit straight out of the box from Darth. It is the molded plastic which I have found is pretty durable, especially after its all glued up and reinforced onto a frame. As with my Bell, though, there will be a lot of work to get it looking really nice. But that’s what I like about them. You can either slap it on and fly or really take your time to detail.

Plans include:

Custom made retracts with working gear doors.
Smoke, see through windows.
Flipped tail rotor to left side for scale look.
Raised tail with (hopefully) 4 bladed tail rotor.
4 bladed main rotor, with CCW rotation.
Opening pilot doors to access battery.
Access panel behind rotor mast to remove electronics
Lights (of course!)
And a special paint job based on a real life heli. (Keeping that a secret!)

Build:


Step one was to mock it up with the pieces taped together and figure out where and how to insert the mechanics. Darth suggests keeping the nose as a separate piece. This worked great for the Bell 222, but since my plans for the gear doors are a little complicated, I want to make the main fuselage one piece. Hence the need for the doors to open to gain access to the battery.


This is the line that I plan to make the access hatch. Somewhat scale like, as the real S-76 has the engine cowling slide off there.

I’ll post some more pictures in the next day or so once I get the edges cleaned up and trimmed.

[majuro15]

Day two of the build. I got a lot done today and last night. All the windows are cut out. I learned this time that it is much easier to score it from the inside with an exacto rather than trying to make it perfect from the outside like I did on my first scale.

http://www.helifreak.com/attachment.php?attachmentid=45580&stc=1&d=1208584647

I also cut all four cabin doors out and found some great hinges from my LHS. I was debating on making my own to mount internally like the full size heli has but for this size, it's just too much work. I plan on filling these to make them look as smooth as possible.

http://www.helifreak.com/attachment.php?attachmentid=45581&stc=1&d=1208584897

http://www.helifreak.com/attachment.php?attachmentid=45582&stc=1&d=1208584897

I added some small handles for the doors as well. Not exactly perfect, but I have to have something to actually open the door since I'll be putting batteries in through them. I will use small magnets to keep them closed, but I will mount those last to make sure I even the doors up once it is all mounted.

Here is a shot of the mechanics on a test fit. I am using a carbon fiber plate in place of the bass wood. My retract pieces should get here this weekend, so that is next.

Last step of the night is to glue the forward and mid sections together and let dry overnight.

http://www.helifreak.com/attachment.php?attachmentid=45583&stc=1&d=1208585206

More updates tomorrow evening. I hope someone is reading this and enjoying it! Kind of dissapointing to not have any replies on any of my posts.:roll:

[smoothb10]

Looks great cant wait to see it finished .nice touch with the doors .what are your plans on battery access?

[billbill242000]

More updates tomorrow evening. I hope someone is reading this and enjoying it! Kind of dissapointing to not have any replies on any of my posts.:roll:
Don't get dissapointed. Just so far everthiing clear and easy to understand. Just where did you get the kit?

[xxkiloxx]

Great job so far! Are you going to do a direct drive tail or a belt? I ordered a Blackhawk kit from Darth a few weeks ago. I will post as soon as I get going on it. Keep up the good work!
-mike

[billbill242000]

Who is Darth??:confused:

[PlagueWulf]

Who is Darth??:confused:
Vader? :P


Try this link:
http://darthdrk.4t.com/


Very interesting build, looks great so far - i will follow it closely! :thumbup:

[billbill242000]

Thanks!!:cheers

[majuro15]

Thanks for the kudos.:lol: The tail is going to be belt driven. I have ordered an elevated tail for it. I wanted to at least get it flying before I tackle that issue. There will have to be modifications, though, as the fuselage is shorter than the stock boom. I will have to cut it down and add more to the elevated part to make it fit. All the while, making sure that the longer belt will stay tight.

The weather was great here today, so I spent most of the day outside flying! I did get some work done on the mechanics though. I finished redoing the head to make for a CCW rotation. The tail has been done for a while, but I was waiting on a new V2 head to come in. A lot of tinkering, but once you do it, the job isn't that hard.

http://www.helifreak.com/attachment.php?attachmentid=45751&stc=1&d=1208745194

It was a little tricky getting the gyro and rudder servo to work correctly. Everything is backwards so after my first test spool up and the thing windwilling like a psycho, I figured it out. After that, it was very smooth! Many people had warned me of the differences, but I'm so new at the hobby that I didn't notice a big difference. It wants to go right on lift off instead of left, but that's it.

http://www.helifreak.com/attachment.php?attachmentid=45755&stc=1&d=1208745194

I did work on the fuse a little today. I filled in the gaps between the forward and mid sections that were glued previously. I also attempted to smooth out the hinges on the doors, but the putty I have is not very workable so I am holding off until I get a different kind tomorrow.

That's it for now, here is a pic of the new CCW bird and my Bell 222.

http://www.helifreak.com/attachment.php?attachmentid=45757&stc=1&d=1208745194

[billbill242000]

OK..call me clue less...why change the direction of the head? How do you do that?

[smoothb10]

because the helicopter hes modeling spins counter clock wise

[billbill242000]

OK so it's for the scale appearance of the project. How do you change the direction of the rotors?

[modelholic]

Can't those hinges go on the inside?
Looking good.

[rgallant]

You will have fun with the belt, hopefully it will be close length. What I did on the Blackhawk was get all the bits together and stretch the belt and mark the boom where it ended Then from that mark stretch to the end and count the teeth. White paint helps :). That will give you a rough idea of the belt length in teeth, you will have to order a couple of sizes to get a good fit. If you are close to 498 let me know I have a few spares you can have.

[majuro15]

Yes, the direction of the rotors are for scale look. Also just another challenge for me to take on!

There is a lot more to it than I thought to change the direction, but it is complete. You have to flip EVERYTHING on the head as well as the one way bearing. I also flipped the tail and reversed it as well. All in all, fun but time consuming.

I got the tail all done and have an idea to use V2 servo rod guides for the flex rod. Zip ties had to be too tight to stay in place wich caused binding on the servo. If you dont zip the flex rod to the boom, then it just flexes instead of moving the slider.

I got the hinges all smoothed over, or at least as good as I'm going to get them. They can't go on the inside because there would have to be too much space between the skin and the door. It wouldn't open correctly as they aren't a floating hinge. Either way, looks pretty good. I'll get some pictures up tomorrow.

Now I'm just waiting on the retracts that I am going to modify. I need those to mount inside the body before I can go any further.

[majuro15]

Long time coming update here on the S76 Trex project.

I finally got the four bladed head from Lightning Heli installed and tuned up. I posted another review of that you can read under the scale section. Still getting used to it, but very cool! And it looks amazing! I also made a cascading four bladed tail rotor. This helps tail control with the massive new head and also looks scale for this heli.

I have made a lot of progress in the past couple of weeks. I decided to abandon the open door idea. The hinges worked great, however the plastic was not holding its shape. I had intended to have two tiny magnets on each door to hold it shut, but they didn't fit the curve of the fuselage anymore. So, on those went in lieu of an access panel.

First was a platform for the mechanics and gear.

http://www.helifreak.com/attachment.php?attachmentid=57083&stc=1&d=1217470652

Fairly straight forward. The retract mechanisms are from a .10 sized airplane. I found them online somewhere. I made my own gear. If I get really daring, I might put some balsa on it to spruce it up instead of a metal rod.

http://www.helifreak.com/attachment.php?attachmentid=57084&stc=1&d=1217470652

Next was to make up the doors. The hinges were tough as it has to have clearance to open from the inside and I didn't want to have an ugly hinge on the outside. So I used aileron hinges and they work great! Very stable and the plastic cement holds them well. I've managed to drop it on the table while working on it and knock on wood, no problems!



http://www.helifreak.com/attachment.php?attachmentid=57085&stc=1&d=1217470652

http://www.helifreak.com/attachment.php?attachmentid=57086&stc=1&d=1217470652

[majuro15]

The nose gear doors are pretty simple as they are mostly hidden, I wasn't as particular on those. I don't have a good shot of them closed yet.

The next step was gluing the two pieces together. Tricky! Once you glue them, that platform is in there for good! I made an access panel on the top that I can slide the mechanics in and out. Tight but perfect fit. I attach with four screws from the bottom. I made sure my wires for the gears and future lights are set.

I also spent a long long long time on the doors and gears. This has been the hardest thing, as I did not want to have multiple servos and the extra weight of a sequencer. So, the back doors are with a very fine flex rod. This serves to hold them open and start the movement. I found though I could never time it right to keep them closed. It just happened to work out that the mount for the rod on the door matched closely to the retracted gear. So as the gear finishes retracting, it catches a small piece of plastic to hold the gear door closed and flush. I'll have a video posted on YouTube when I get done.

The front have a direct linkage since it is more cramped on room under the battery and are closer together. I have a link going to an L bracket which has another link going to the gear door. As the nose gear comes down, they open up and vice versa. Took a lot of time, but I have both sequenced very good.

http://www.helifreak.com/attachment.php?attachmentid=57088&stc=1&d=1217471619




http://www.helifreak.com/attachment.php?attachmentid=57090&stc=1&d=1217471619

http://www.helifreak.com/attachment.php?attachmentid=57089&stc=1&d=1217471619

[majuro15]

And finally, the tail. This was the vital part, as I want to be able to work on the mechanics and change out belts. First step was to make an elevated tail kit using the High Torque as a guide. Theirs was flimsy and cheap and broke after a light crash. So I made my own (maybe another thread if anyone is interested.) I don't want a lot of seams from piecing things together on this heli, so I wanted to make the tail one big piece.

I decided to make access panels for the bits I needed to get at. This way, I can unasymble the rotor area and slide the whole tail piece off of the tail boom to replace the belt, etc. Once the panels are on, they look great, makes it more real appearing, I think. Not the easiest for maint. but it's doable. This will be mainly a show flyer anyway as my Bell 222 is my daily flyer.

http://www.helifreak.com/attachment.php?attachmentid=57105&stc=1&d=1217476257

http://www.helifreak.com/attachment.php?attachmentid=57106&stc=1&d=1217476307

To slide the mechanics in, I cut an access panel. It's actually along the lines of the real bird (sorta). I put the main frame in, fully assymbled and then slide in the tail boom. It's pretty easy, but boy was I nervous the first time (what if it didn't fit???) :shock:

http://www.helifreak.com/attachment.php?attachmentid=57107&stc=1&d=1217476376

http://www.helifreak.com/attachment.php?attachmentid=57108&stc=1&d=1217476376

The silver things on either side are the flex rods for the main gear doors. It is foil tape, which helps the rod hold its shape. I was worried that it would cause the radio to loose signal, but I have a remote receiver and did a range check (non flying) and had no problems with the DX7.

http://www.helifreak.com/attachment.php?attachmentid=57109&stc=1&d=1217476376

So that's it for now. Next up will be cutting the panel in front of the main mast for the battery and making the four screw mounts to hold the tail cone. After that, lots of puddy and sanding to make her smooth, install the lights (all in the tail cone on this heli) and paint! I plan on doing a test flight once I get the tail mounted just to make sure I don't have any problems.

I love this hobby!

[Buzzkill]

Great build! Am I the only one that can't see the pictures in the last post?

[majuro15]

Uh oh. I can see them. Anyone else? They are the best ones!!!

Thanks for the kudos!

[trexflyer02]

Uh oh. I can see them. Anyone else? They are the best ones!!!

Thanks for the kudos!

I couldn't see them before, but I can now.

Great job, looks like it's going to be an AWESOME build. :thumbup:

[Buzzkill]

I can now.

[batdive]

nice build keep the updates coming....




-=Bat

[majuro15]

Okay, got the last major bit of construction done tonight. The access to the battery is through the roof of the cabin. I was a little nervous once I cut it as I realized my idea of a tounge and groove system wouldn't work due to the curve of the fuselage where I cut. But I came up with a better idea using the rest of my rare earth magnets. The pictures show better, but I made four tabs each on the hatch and the fuse and put one magnet in each one. This way I can slide the hatch in and it is very secure!

http://www.helifreak.com/attachment.php?attachmentid=57231&stc=1&d=1217561300

The magnets are behind the white square hanging from the edge of the cut. They are pretty secure, but then again won't be hit by anything other than a crash which, lets face it, will total this heli anyway!

http://www.helifreak.com/attachment.php?attachmentid=57232&stc=1&d=1217561300

http://www.helifreak.com/attachment.php?attachmentid=57233&stc=1&d=1217561300

http://www.helifreak.com/attachment.php?attachmentid=57234&stc=1&d=1217561300

The hatch lines up great when you take your time (more than one second!). Here I just threw it on for a pic so there is a bigger seam than usual. Once painted (including the edges of the hatches/holes, I think it will go almost unnoticed. Once you are further than a foot from the bird, you can't see it anyway.

http://www.helifreak.com/attachment.php?attachmentid=57238&stc=1&d=1217561300

I haven't spooled it up yet, but I did test it to see how easy the battery removal is. It's actually perfect. I plug it in first and then just lay it in and secure it with the regular velcro loop. All the while, the ESC is beeping, by the time it's done, I have the hatch on and ready to go!

Tomorrow night, I hope to have a video of the gears and how the hatch works. I still need to tweak the nose gear a little as I am getting some binding from the servos. I know its bad for them, but I've gotten the rear as good as it's going to get. Once I move the whole bird around by the head, it stops, so I'm not too worried about burning them up. If so, oh well, they are cheap.

More to come soon!

[trexflyer02]

Okay, got the last major bit of construction done tonight. The access to the battery is through the roof of the cabin. I was a little nervous once I cut it as I realized my idea of a tounge and groove system wouldn't work due to the curve of the fuselage where I cut. But I came up with a better idea using the rest of my rare earth magnets. The pictures show better, but I made four tabs each on the hatch and the fuse and put one magnet in each one. This way I can slide the hatch in and it is very secure!

The magnets are behind the white square hanging from the edge of the cut. They are pretty secure, but then again won't be hit by anything other than a crash which, lets face it, will total this heli anyway!

The hatch lines up great when you take your time (more than one second!). Here I just threw it on for a pic so there is a bigger seam than usual. Once painted (including the edges of the hatches/holes, I think it will go almost unnoticed. Once you are further than a foot from the bird, you can't see it anyway.

I haven't spooled it up yet, but I did test it to see how easy the battery removal is. It's actually perfect. I plug it in first and then just lay it in and secure it with the regular velcro loop. All the while, the ESC is beeping, by the time it's done, I have the hatch on and ready to go!

Tomorrow night, I hope to have a video of the gears and how the hatch works. I still need to tweak the nose gear a little as I am getting some binding from the servos. I know its bad for them, but I've gotten the rear as good as it's going to get. Once I move the whole bird around by the head, it stops, so I'm not too worried about burning them up. If so, oh well, they are cheap.

More to come soon!

Again, great job with documentation and pictures majuro. I look forward to tomorrow night's videos and beyond! :)