7HV Build Tips

[crawl]

Thought a thread dedicated to build tips for the 7HV would be nice. Those who have them already please chime in with anything you have to share, much appreciated!

-Ground the ESC to motor mount
PunchRC ESC has a wire for this purpose
-Ground Boom
We know we get static hits on the 6hv, the 7hv has a wider and longer belt and it is fairly safe to assume we will have some static if not grounded.
(personally I will use the same style as 6hv, boom to motor mount, gives common ground with ESC)


That is all I know of so far. I am sure we will have more once we all get our kits.

[Dave Ketelhut]

i agree about grounding the helicopter. if you ground the ESC to the Frame, please make sure when plugging the batteries up you do not touch the positive wire to the frame by accident. trust me

[crawl]

i agree about grounding the helicopter. if you ground the ESC to the Frame, please make sure when plugging the batteries up you do not touch the positive wire to the frame by accident. trust me

Is their a better/safer way to ground the esc?

[Dave Ketelhut]

when you ground the ESC to the frame there is really no way around it

[BakedMopar]

I see in a lot ofthe 6hv threads that the ball links need to be sized. Same with the 7HV? Any recommendation on a sizer?

[myrseth]

Compass sizer.

For grounding, just draw a cable between main shaft block screw to motor mount screw, then main shaft block screw to boom block and you grounded the entire thing, also ground esc to motor mount screw. But as David say don't fool around with the + cable. I find I get better range checks too with this setup

[BakedMopar]

Like this (http://www.nankinhobby.com/Helicopters/Tools/Ball-Link-Sizing-Tool-4-75mm/prod_6263.html) one?

Grounding esc meaning negative input wire to mount?

[myrseth]

Compass order number: E-XQT-01 Balling sizing tool

Super tiny, had several different types inc JR but for some reason when its this tiny you get more presision and steady sizing so the links are much easier to get just right.

[alexmit]

Compass order number: E-XQT-01 Balling sizing tool

Super tiny, had several different types inc JR but for some reason when its this tiny you get more presision and steady sizing so the links are much easier to get just right.

I use the JR ball link sizer. I do not see the Compass sizer in stock at Nankin. Is the Compass sizer really that much better? if so, I'll grab one at some point.

[myrseth]

I like it because its very small, you have to operate it with two fingers, it means you can keep the sizer stable and 90 degrees to the link much more easy when sizing the link, no whops wider links that gets loppy because you slipped a little or something like that. I favor the compass one, ye ye I know im a sponsored pilot and all but I got 4 sizers but keep using that tiny one hehe.

[BakedMopar]

My main shafts holes are different spacing from the ends. Can anyone tell me what way is which?

[Rob43]

It appears to me the end with shortest distance to hole is oriented to the bottom. I don't think it will clear the battery plate if you place the "long" end down.

[Ah Clem]

"It appears to me the end with shortest distance to hole is oriented to the bottom. I don't think it will clear the battery plate if you place the "long" end down."

I am looking at the instructions, and I tend to agree with Rob, based on the diagrams.

It looks like the end of the main rotor shaft with the hole closest to the end should go down, and the end of the shaft is effectively flush with the bottom of the lower bearing.

[Rob43]

I have found a few very minor items to pay close attention to as usual for any heli, rollout, or established:


Servo cap screws should be M2.5 x 8. Instructions say M2.5 x 10. M2.5 x 12 were provided. Cutoff wheel.
The boom brace clamp/control rod guide is cool, but came with a M3 x 35 screw. Instructions say M3 x 25. I think that would work fine. Cutoff wheel.
I thought I would remove the tail hub to loosen up all the joints for free working tail. Unfortunately, my Thorp 2mm hex driver snapped off in the grub screw. I tried several ways to remove it. I opted to abort the mission. I will replace the entire shaft and hub when the time comes. For now, I just resized the all links. I expect I will need much more attention to the tail before maiden. The ball link pivots are pretty stiff, and the sliding action of the yoke across the shaft each add friction. Nothing major here. TLC.
Mounting servos is pretty easy. However, take care to maintain precision alignment of the upper and center bearing blocks, as they are spaced according to the servos. I used my main shaft position in the bearing blocks (there's three of them!) and kept tweaking screws and alignment until I had them all snug and could drop the shaft all the way through. I expect this will cause vibes for some less careful builds. Oh, servo arm throw length spec'd is 17.5mm all around and tail. JR heavy duty arms, with balls NEXT TO LAST hole.
Anit rotation guide. Much nicer plastic part without any major cutting needed. I did have to file the slot open more to clear the pin. The pin was very tight in mine. I used a small flat file.
Tensioning the belt: it's a little different since we now have a tension idler with a rubber band to load it. I simply pulled out the boom until the idler is in about the center of it's travel. More might be better. I will need to see it's on the slack side of the belt, so it will mostly move towards the boom center line under hard tail tail pitch commands
It took me like 90 minutes to remove the adhesive smag left from the piece of packing foam used on the bottom of the removeable battery tray. I wound up using packing tape after scraping off the foam with a plastic scraper. Just pat the fresh packing tape against the remnant adhesive to get it to come off. Alcohol was no no help at all. I think the tray is made of G10. It slides in real nice- just like Whitesnake...LOL!
I am finding my servo swash links a touch longer than the instructions...57mm is spec'd. I might have closer to 60mm but not done yet.
The motor mount is jewelery of the sweetest kind. A well hung beast! When you get yours, remove it and check the motor for continuity to the shaft for all three phases. Mine was fine.
More later.

[BakedMopar]

It actually clears both ways but i'll agree with you that it does fit a little nicer with it that way.

I've run into the main gear rubbing the belt. Does your do this also?

http://www.helifreak.com/showthread.php?t=316115

[Ah Clem]

"It took me like 90 minutes to remove the adhesive smag left from the piece of packing foam used on the bottom of the removable battery tray."

I have had this issue on a number of items, not all helicopter related. A good friend of mine suggested WD40 to remove the gum adhesive. I don't know if it will work with this particular adhesive, but it certainly would be worth a try.

[Rob43]

I thought about WD40 when I was working on it. I wasn't sure if the material would be compatible with it or not. I played it safe.

I am very unsure of electronics placement. Looks like Vbar and sensor will both fit on the gyro tray out back. receiver and superbec - I don't yet know.

[Rob43]

It actually clears both ways but i'll agree with you that it does fit a little nicer with it that way.

I've run into the main gear rubbing the belt. Does your do this also?

http://www.helifreak.com/showthread.php?t=316115


I replied to your post, but I am not sure it will help you. Something isn't at the right height if your belt doesn't align with the pulley. First see if the belt exits the boom in the center. It should...then check each pulley until the main pulley. Something isn't positioned right if that isn't aligned.

[wolfdown]

For the love of god, is nobody going to post any build pictures? :bawl

[666yeti666]

some of my picturees are found here : http://www.modelbouwforum.nl/forums/bouwverslagen/138234-compass-7hv.html

sebastien

[wolfdown]

thanks! Does it really ship 90% assembled like that from the factory, or was that a special kit?

[666yeti666]

yes it does and uptill now, all my bolts contained threadlock, some even a bit to much ...
The kit is very rigid built.
sebastien

[TheBum]

The Compass E-helis all come with the frame assembled.

[BBRFST]

Help, Which hole are we using on the head block the lower or the upper one? It seems that at the recommended lengths of 58mm on grip arms and 57mm on servo links with servos at center I have a bunch of neg. in the blades.:dontknow

http://helifreak.com/attachment.php?attachmentid=237359&stc=1&d=1309401919

http://helifreak.com/attachment.php?attachmentid=237360&stc=1&d=1309401919

http://helifreak.com/attachment.php?attachmentid=237361&stc=1&d=1309401919

[Rob43]

Mine's like yours Sean. I think the delrin rods from the swash to grips would need some work to reach if you run the head higher. Not positive. Bird should fly best like you have it.