Marvel Craft A109S on TRex 600

[majuro15]

Hey Everyone,

I finally got in gear and am knee deep in Augusta again! I decided to ditch the Thunder Tiger fuse in favor of the newer Marvel Craft from Joe at East Coast Scale. I must say, for me, it was a good decision. Marvel Craft details are just so much better than the TT. Those, combined with the precut pre-molded doors, better access to the interior, and the S model vs. the E was the icing on the cake.

I'll get up to date via a couple of posts, but the first priority was to get the mechanics flying well in pod and boom, since that was what made me put the last one to the side.

The stock TRex 600 already has the Scorpion 4025 and the CC 100 ICE controller along with new 6s Zippy 50C 5000mah batteries to power it. The RX, lights, and another accessory will all be powered by seperate 2s lipos.

I decided to ditch the Lightning Heli (or whatever brand it was) 4 bladed head in favor of the RC Aerodyne plug and play model. I actually ordered it direct from Flying Hobby, and got lucky with upgraded links (or at least ones with no quality issues). This head is much better in many ways. Plug and play is nice, but so is the finish, quality of hardware, and assembly. Everything is true, runs smooth and balanced and was locktited from the factory.

I also upgraded the lacking SK360 to the SK720. I spent two days setting up the SK720 using the power bus and PC interface. I must say it was worth the time spent. A lot of tests on the bench, runs without blades, and double-triple-quadruple checking equaled a perfect maiden flight with it and the new head. No twitching, no random movements, and best of all, no blade strikes! I have since put almost 30 flights on it and have it all fine tuned. I had a little bounce in the elevator which was solved by turning down the bell gain.

The next upgrade for the mechanics was blades. I went from the Align stock blades (4) to the Rotorcraft scale set. Not only do they look great with the angle tip and yellow paint, but also are weighted completely different. Heavier, farther out CG, and leading edge heavy on the chord made a huge difference in flight. I was concerned about losing lift from the narrower chord, but actually hover at below half stick now vs. right at it with the Align blades! Only down side is loss of the clap that I had that made is sound so cool, but that will come back as I add weight and use more AOA.

I also put an 800 boom and TT on it, to better fit in the fuse, which I’ll get to later. I’ve spent a lot of time flying and can now comfortably hover nose in and fly most scale maneuvers. I’m really working on my approaches and landings nose in this week. It’s a whole new experience flying comfortably, not being afraid of it all the time. And best of all, I’m flying the heli, it’s not flying me!

[majuro15]

With the fuse, the woodwork was first priority. It's a similar to the TT with no metal for the main gear supports. As it's a generic fuse with no instructions, it took a little bit to get worked out, but very nice quality. All laser cut ply that was very easy to assemble. I built it up and then played with the mechanics location inside. Originally, I had a 700 boom on it, which was going to work for the TT fuse, but not for this one! I needed another 1.5" or was going to have to move the horizontal stabilizers, not a fun job. Turns out the 800 boom worked well and allows me to move the mechanics forward. Unfortunately I didn't get the 800 boom until after I made the wood work for the 700, so that has to be redone.




While I was waiting on the boom, I went on to the gear. This is where I really wanted to focus and make a scale gear. The fuse comes with the retract mechanisms and wire, but weren't a good fit. I decided to go from scrtach. First was the main gear using brass tubing from my LHS. I wanted a shock absorber to help with realism and landings. I got spring from work and the scissor kits from Robart. After doing some measuring based on the stock wires, I built a working prototype. Lots of cutting with a tubing cutter!










The wheels are from Eflight and a half inch smaller than the wheels that came with the fuse. I liked the look better and they are actually rubber, so should hold up a bit better as well as not collapse like the foam. The wood block was replaced with a two piece shaft collar drilled out for the strut and tapped for the ball end. I'm using A7000 retract servo's hooked to a Matchbox and servo slow's for the drive. I'll post those later on.

The gear doors were not included, so those are made from styrene, which I am more comfortable working with than fiberglass. I have both gears complete now, having replaced the socket head screws with set screws which clean up the axle nicely. I'll hand paint these and use lithium grease for the oleo to finish them up.

[majuro15]

Next came the nose gear, which turned out good, but not exactly what I wanted. The shock on this turned out to be too small, as the size didn't conform to room inside the strut for everything that was needed. So I have made this solid. The challenge was to make the wheel caster freely. The real heli has nose wheel steering, which I liked. But, I couldn't find a system to coordinate it and was afraid of the possiblity of raising the gear crooked during a turn, having the nose gear slaved to the rudder channel. I'm going to experiment with the caster and see if it works or is neccessary and then go from there. I can easily JB weld it all and make it stationary. I am using the mechanical retract mechanism for the nose to keep it simple hooked to a HS65 and gear door sequence (later in the project).

[majuro15]

In the fuse, I used the stock ribs without the plates for the mechanical retract system. I'll have a shaft epoxied in with the gear pivoting on that. The cutouts were a bit off for my custom set up, so I layed out the desired shape and went to town with a hot knife (woodburing kit). For the spots that were too big, I filled in with styrene and filler, sanding smooth. Again, never worked with fiberglass and since its so small an area, I figured CA and styrene would work better. Plus much easier to shape! I moved the gears forward in the sponsons a little to line up better with the scale bird. The gear doors have to clear the lights and sit forward in the sponsons just a tad.




I also cut out for the nav lights. I'm using the DeLight system which is a fantastic setup. Very bright, very easy to program, with a lot of lights that will eventually be on this heli! The strobes face the rear (right hand hole) and the nav will face forward (left hand hole).




Inside, the main frames had to be cut to accomodate the longer struts as well as the servo mechanism (to be pictured later). I modified that and installed balsa blocks to hold the servos. I then laminated that with fiberglass to reinforce. I have the servo horns lined up with the linkage when extended, and considering its a lateral force, I'm hoping it holds up to the landings well.

[majuro15]

Finally, the nose gear needed some room and doors to keep the cold out! I mapped out and again went to town with a hot knife but decided it was too big.




I again filled back in with styrene, serving two purposes. One was to fill in the gap, but the other was to step the canopy hinges up a little that I'm using as well as reinforce the fuse around the area. The doors themselves are styrene and cut out to fit around the wheel like the real thing. I couldn't fit the scissor hinge in the doors and still have the wheel stick out, so that had to be cut out as well. I'll make the little lips later on the doors that will flow around the wheel like scale.




I still need to trim the doors back a hair, as they don't open or close fully due to the too-tight tolerance and the movement of the hinges. An easy fix with some sand paper and an exacto.

[majuro15]

Enough gears now!

Onto the outside of the fuse.

Easiest were the horizontal stabilizers which were expoxied in and then gap filled with CA. They had pre-molded slots and fit perfectly. A bit of masking tape and a couple of hours later, they were all set.




The doghouse needed the intake screen and the scoops put in, which came molded in clear styrene. I cut those out and glued them in and they will be painted along with the rest of the fuse. I must say a great scale touch that I didn't have to fabricate myself! The screen will also be painted to blend in, as on the real bird.







I also attached the strake to the tail boom. This was also premolded in styrene, which I added a block of balsa to help attach to the fuse. CA then filler to make it nice and smooth. The real bird has it almost as a bolt on, not molded, but I couldn't get the styrene to cut evenly, so to make it look better I went with filler.




The tail strike was next and was a pretty straight forward drill and epoxy job. I got the beacon (flashing int he case of the S model) light bases cut out for the LED's. I cut a second ridge off and then dremeled out the spot for the LED. I'm using red LED's which will reflect off the clear lense that was also included in the kit. I'll attach the lense with tiny screws to keep any glue away from this. I couldn't get a picture of it, but testing it out, they look great!

[majuro15]

The main cabin doors will be my access point for electronics and batteries. The only thing I don't like is the way the doghouse cannot be taken off without removing the rotor head once all assembled. The doors are precut and molded with CF reinforced into the fuse body, so very strong and very well fitting!. I used small rare earth magnets and some stainless steel to put these on. One magnet in each corner did the trick and makes the door stick out just enough to get a fingernail underneath to pop open. I tested their hold by shacking the darn thing like crazy and couldn't get it to pop off, so not worried about them in flight.




I also added some in the door tracks which were attached with epoxy to keep them in a scale position when open. I tinkered with having a working track system like the real one, but to save weight and complexity, decided against it. Three more magnets embedded in the skin of the fuse will hold them while on the ramp during "turn around" hehe.




The front cabin doors are next and will be hinged (supplied by MC) and use magnets for closure as well.

[majuro15]

Did a little more tonight on it. The gear doors needed more clearance so I was able to sand down the fuse and now they are swinging nice and free. I'm pretty sure once it gets painted and arms length away, a lot of these tiny imperfections won't be as noticeable. I need to trim the doors for the nose gear but will leave that until after I permanently mount the wood work, as there is slop when I try to positing it inside the fuse for the time being.







I got the first cockpit door mounted tonight as well. A lot bigger job that I was expecting, but it looks good. I need to sand the door frame to make it close smoothly. You'd think I would have learned that from the nose gear doors, but nope! No worries though, I can hit it with some 220 and clean it up. I just used CA for now and will go back with epoxy to really secure them. It will be a complete scale cockpit and front cabin, so not a huge amount of use on the doors, but still don't want them falling off. I'll also mount the magnets (one at the top and one at the bottom) with the SS plate this weekend.







Drill this weekend so won't do much. Hoping to hear my pilot training dates, but not holding my breath. ANG = hurry up and wait!

[blade77]

Oh man - This is the fuse I want to build ,but I can`t see any of your pictures - Keep the build info coming - dont know why i cant see the pictures

[majuro15]

Not sure why you can't see the pics. Anyone else having this problem? They are showing for me. I also have a thread over at SRCH. Check it out over there if this one isn't working for you.

[Photog]

No iamges showing here for me....but all good over at ScaleHeli

Cheer
Matt

[blade77]

Pictures are all working now - great build so far

[majuro15]

Thanks!

Yea, now the pics aren't working for me either at work. I'll have to actually upload them on HF tonight to get it fixed.

[helipainter]

lookin forward to it

[majuro15]

Helipainter, me too! I can't wait to get this thing to you for paint! I'm still debating rivets. Man, they would look good, but a ton of work!

I'm working on editing the posts and making all of the pictures work. Not sure what happened, so be patient.

Slowly making progress on the fuse. It's fall, so I'm busy with drill two weekends apart and putting in a sprinkler system in the yard (renting the ditch witch this weekend, watch out! ). I did manage to get the port side cockpit door mounted tonight. As with everything you do the second time, it went much smoother. Lines up a bit better than the starboard side, but I'm happy with both. I got a couple good shots of the whole fuse, as I realized I haven't done that thus far.




Next project is to modify the woodwork again to mount the mechanics with the new 800 boom. I'll cut the tail cone out at the same time and then mount the woodwork permanently.

[majuro15]

Well, I'm going to stop saying dates or time because I never seem to actually make my deadlines! Life gets busy, more house work (landscaping actually) and ANG stuff kept the fuse sitting all alone for over a month. I actually managed to fly some during that time so at least all was not wasted.

I sat down on Sunday and last night though and got back to business. First priority was to modify the 800 size to fit the fuse. I went back and forth on this, as the 700 boom wasn't long enough and the 800 was too long. I also researched the arrow shaft as a TT but vetoed that when I couldn't find a shaft the right size. I also thought about just moving the mechanics to make the tail fit, but they were going to have to go too far forward or aft in the dog house and just not look right. I had to do it the right way even it if it's hard! I have spare TT ends, which worked out great for me in the long run.




So I positioned the mechanics and measured about 23 times. Actually cutting the tube was easy with a tube cutter and I drilled out the inside of the shaft to accept my spare TT ends. Once I filed the inside down a bit to make sure it was true, I tapped two holes to secure the end. I thought about JB welding it, but decided against it, as with the set screws, I can adjust it a bit if it's not perfect. I put it all back together with no blades and did a bench test and it's very smooth with no bad vibes (at least not yet!). I got a Gold N Rod from my LHS and need to get that set up for the tail servo, which I'm going to mount in the mechanics near the elevator servo, helping balance and cleanliness!

Next, I worked more on getting the woodwork permanently bonded so I'm checking the to-do list off for that. With the tail sorted, I drilled out for and mounted blind nuts for the four bolts in the wood work to mount the mechanics. I'll be including a top brace down the road as well. As simple as this is, it feels like I made a huge step, as the mechanics now have a "home" in the fuse!



The last things are the gears and electronics that won't be easily accessible once the woodwork is in. I fitted and mounted the nose gear mount along with the servo for it. I went ahead and made up the linkage using one of the pieces that came with the kit (originally for the mains, but I'm not using that set up). I also mounted the two servos for the gear doors and put the door sequencer in place. I'll be programming that for the gear itself first then the doors once the woodwork is bonded and the links are done.



I also did some more mods on the mechanics themselves, replacing the stock 600 main gear with a KDE gear along with KDE hub and bearing and putting a new Align auto tail gear on. I suspect this was a cause of some vibes I was picking up on my SK720. After the bench test, it's visibly smoother and calmer, so hope that helps bring vibes down to below 1.0. I put a KDE gyro mount in too, with the proper mounting for the SK.

Next to do is finish the tail servo rod, clean up the wiring in the mechanics including hooking up the SK power bus, and installing the electronics for the main gears. Then I should be ready to bond the woodwork in and install the main gears and have it sit on its on legs!

[majuro15]

PS, sorry for those posts that the pictures aren't showing up. They are too old for me to go back and edit. If you want to see them, click each one and they should pull up.

[Hank79]

Beautiful work, the landing gear is very impressive, I'm really looking forward to seeing what colour scheme you will go with

[majuro15]

Thanks! Hope to have it on the gear soon!


Got some more work done last night on the mechanics, as I'm finishing those up for installation tests finally. I spent some time reconfiguring the SK720 for its new mounting direction. I also rerouted the servo wires to accommodate the rudder servo being mounted on the frame. I still have a little bit of wire management to do with the power bus this evening. On a side note, I really wanted to use a CC BEC 10A for the power bus and have a switch inline from the lipo, but the thing makes the SK go crazy. I guess I'll stick with the stock Align BEC, as it's done a great job for me thus far.

I also finished up the flexible tail servo rod and got the tail sorted again. The mounting was pretty easy, as I used aluminum foil tape to secure the outer rod to the tail boom. The challenge was to support the cable near the boom block while still making the whole assembly removable for service and installation into the fuse. I came up with a little support block that I have screwed to the boom block. Not beautiful, but very functional and that's what matters now. I never have luck with soldering these kind of things, so I stuck with JB Weld which worked great. I had some scrap that I did a test and really mangled it before it broke, so no worries about the tail giving out while flying.





I also did one last test fit of the woodwork in the fuse with the rear retract servos mounted. I am going to do one last check (read: sit and look and think for 30 minutes about what I could be missing) before CA'ing the wood in next time I work on it. Then I'll go back and epoxy to secure it. Hoping to get the mechanics back in the air for some test with the new tail as well.

[helipainter]

good job, just about in. what ca, what epoxy are you putting that in with?

I got to see some of these up close at Scale Masters, nice fuses!!!!!