Roban AH-1W Cobra 700 Size Scale Helicopter

[sfcfury]

Well now, don't take my word as the gospel lol... I fired up the castle link software and this is what it says: 500kv motor set at 1250 is 86.3% on the ESC, 1300 is 89.8%,1350 is 93.2%, and 1400 is 96.8% . So 500kv will get the job done... just my personal preference to have a lil more room on the top end. Hey, I'm a copycat of Rcjetdude, I asked him what motor he was using on his 700 apache.... I went and checked them out, and just wanted to give this motor a try. I also have a scorpion motor. There's definitely more experienced guys on here that could throw their two cents worth in as well.

[PawPaw]

You were absolutely correct! I tried the numbers on ecalc & they were close to yours. I ordered a Scorpion HK-4035-560 instead. FedEx says my AH-1W will be delivered tomorrow, so I’ll just occupy my time detailing until components arrive. Looks like I’m out of luck on the CC Talon 120 as everybody seems OOS.

[sfcfury]

You ordered it this morning and it will be delivered tomorrow? Holy crap batman! You must've gotten the super delivery service lol...

[PawPaw]

Haha.....I ordered the heli yesterday morning (27th). Motion confirmed shipping in the afternoon. Just their regular free shipping. I ordered the Scorpion today.

[PawPaw]

Sfcfury, what’s your opinion on metal servo arms? I have them on my 3D Extra but only because of the length required. My Cobra arrived today & I read Roban specs metal arms. My servos are all metal gear digital HV, so I certainly will order the metal arms if nylon ones are the “kiss of death” to a 700 heli.
My thoughts (prob incorrect) are that a nylon arm could fail before the servo gears in a rotor strike, thereby providing some level of servo protection. Whatcha think?

[DCORSAIR]

Guess I better change out my servo arms if that is the case, I bought my 800 Roban AH-6 already built and flown with everything installed and the guy had the plastic servo horns all hooked up so I just used them not really thinking about a failure, guess I better order some metal ones soon.

Now get on that Cobra build.

[PawPaw]

Thanks, DCORSAIR! In 40+ yrs of ac flying I’ve never had an inflight servo arm failure, but have stripped servo gears in crashes. I’m pretty new to helis but my take on the necessity for metal servo arms must be focused on high control forces, or the concern for slop developing in the ball link shaft hole in the plastic arm. I’m inclined to stick with my nylon arms most especially since I’ve installed ‘em already.

Had to change my electronics checkout plans today due to the fact my Demon 3X FBL requires a PC connection before startup, and I don’t own a PC. 🙄

[DCORSAIR]

Thanks, DCORSAIR! In 40+ yrs of ac flying I’ve never had an inflight servo arm failure, but have stripped servo gears in crashes. I’m pretty new to helis but my take on the necessity for metal servo arms must be focused on high control forces, or the concern for slop developing in the ball link shaft hole in the plastic arm. I’m inclined to stick with my nylon arms most especially since I’ve installed ‘em already.

Had to change my electronics checkout plans today due to the fact my Demon 3X FBL requires a PC connection before startup, and I don’t own a PC. 🙄

Yeah, I now have five flights on my big bird with the nylon servo horns, have to say though, I think they will be just fine really, this thing flies so scale, big and slow and even though I know there is force on the controls horns, they only move just a little, very little movement is all I have to fly scale, I don't plan on flying 3D with it but I would maybe feel a little better if I had the metal horns, so I might order some or just keep flying it the way it is. I'm using the Microbeast 5.0 in my AH-6, works great, tail holds solid and you don't need a computer or anything to set it up, only thing is, it helps to have it mounted in a place where you can get to it if you need to program it, mine is actualy hidden once I put the cockpit back in but I have it all dialed in, so no need for adjustment so far and if I need to make any adjustment, 3 screws and I can get to the Microbeast. I like the Microbeast so much I put one in my 800 Magnum PI version that I am building now.

[sfcfury]

I'm using the the heavy nylon ones that came with my servo's... I can't fathom stripping those big nylon ones in scale flying... never ever gave it a second thought to be honest... but again I'm very far away from being a subject matter expert. I use the AR7210 Beastx myself... I have it on 3 heli's thus far and it does what I need it to do.

[sfcfury]

DC I was tinkering with you AH-6 lil cousin/old ancestor lol... I have a 500 size I have been doing up as an OH-6... I put speakers in the bottom etc lol.... I did okay with the tail... I'm satisfied lol. I see some of the guys take banana peels and a piece of Styrofoam and make an exact duplicate of a cockpit!! I just don't have those kinda skills


Not too bad considering it was a Magnum PI kit lol.

[DCORSAIR]

I'm using the the heavy nylon ones that came with my servo's... I can't fathom stripping those big nylon ones in scale flying... never ever gave it a second thought to be honest... but again I'm very far away from being a subject matter expert. I use the AR7210 Beastx myself... I have it on 3 heli's thus far and it does what I need it to do.

Great, glad you like your Ar7210, I have heard nothing but great things about it, I use Futaba so it won't work for me, I'm no expert either and was having a hard time getting rid of my flybared scale helis but now that I went to the FBL 800 size helis and started with the Microbeast, I really like them, once I get more experience I will try another unit, the Microbeast turned out to be easier than I thought setting it up.

Can't wait to see your Cobra in the air...

[DCORSAIR]

DC I was tinkering with you AH-6 lil cousin/old ancestor lol... I have a 500 size I have been doing up as an OH-6... I put speakers in the bottom etc lol.... I did okay with the tail... I'm satisfied lol. I see some of the guys take banana peels and a piece of Styrofoam and make an exact duplicate of a cockpit!! I just don't have those kinda skills


Not too bad considering it was a Magnum PI kit lol.

Love it, looks awesome, I kind of do wish Roban would have done the big 800 AH-6 with the short skids like yours, but I don't have the skills to shorten them and I actually do like the tall skids on the regular Hughes 500, there are some AH-6 with the taller skids, I guess I have the rare version, flew it today actually.

[sfcfury]

I actually cut an inch off of my skids... going into the frame and the actually 'skids' lol. I've been looking at the 800 size AH6 (and there's a white navy OH6)... they just look so tall to me... like the skids seem dis-proportionally sized. Yea I saw that you had flown yours as well! I swear these roban kits should be labeled as 'you will need to purchase a dremel tool'!

[F106DeltaDart]

I actually cut an inch off of my skids... going into the frame and the actually 'skids' lol. I've been looking at the 800 size AH6 (and there's a white navy OH6)... they just look so tall to me... like the skids seem dis-proportionally sized. Yea I saw that you had flown yours as well! I swear these roban kits should be labeled as 'you will need to purchase a dremel tool'!

Nice! I ended up trimming my skids by an inch on my 500 AH-6 as well. It has always confused my why they went with the tall skids on the 800 versions.

On another note, this thread has caused me to get the Cobra down from the shelf and look at getting back to it. I’m planning on rigging the FLIR and gun for servo movement, and am considering adding a spinning barrel to the gun as well. I’ve though about using a jack screw (like the LX actuators) but I think it would look too slow. Anyone have any suggestions on a small motor/mechanism to spin up the barrel?

[sfcfury]

Nice! I ended up trimming my skids by an inch on my 500 AH-6 as well. It has always confused my why they went with the tall skids on the 800 versions.

On another note, this thread has caused me to get the Cobra down from the shelf and look at getting back to it. I’m planning on rigging the FLIR and gun for servo movement, and am considering adding a spinning barrel to the gun as well. I’ve though about using a jack screw (like the LX actuators) but I think it would look too slow. Anyone have any suggestions on a small motor/mechanism to spin up the barrel?

That's above my skillset!! LOL... That's the reason I come here to see how to do those kinds of things

[DCORSAIR]

I like the look of the tall struts myself, just not on the AH-6, it needs the short struts to look right, oh well it is what it is, maybe one day I will experiment with the idea of cutting down the strut length, I do have a brand new set to experiment on, or wait until I crash it, then it will have shorter struts I'm sure.

[sfcfury]

I think more what might scare me... it just seems tall... like it would wanting to teeter... a little bird with stork legs . I like it tho! Likes like it flies nice!

[sfcfury]

So I did my first run up with the fuselage on... just looking for any crazy vibrations... seems okay. Gonna have tinker with the the upper tail rod link; its catching on the very tip of the tail piece... here goes the dremel again lol.
The first speed it spools up to is 1050 which its at about the 25 thru 30 sec mark, then I pass through 1350 for about a second lol, and then the end 30-35 secs is at my throttle 2 which is 1400rpm (which I think will be my flying speed).

[sfcfury]

The upper tail pushrod catching at the very top... It's like the boom is just a hair off center. I dremeled a little bit off already, but it's still touching.

[DCORSAIR]

The upper tail pushrod catching at the very top... It's like the boom is just a hair off center. I dremeled a little bit off already, but it's still touching.

Sounds great to me, but looks like one of the reasons the rod is hittiing maybe, you need to square up your tail rotor shaft with the fuselage, that will swing the control rod back to the left, the whole tail unit looks off to me, I had the same problem with my Roban Bell 212, but it just needed a little dremel work at the top of the fuselage, had a little lip on it and was snagging the linkage also I put some foam around the top of the boom and a little more on the right side and this pushed the boom over a little to clear the linkage even more plus I always add foam anway to help dampen any vibes back in the tail section, just make sure you don't stuff to much and jam the rod.