Jerry's HeadHunter "500" build

[dunkonu23]

Some days you're the windshield and other days you're the fly, bro.

Scott

[Jerrymac]

Well, I have been able to squeeze in a few minutes here and there on the HH build, so here is a lenghthy update.

Scott told me that he had a little trouble getting the screws into the spacers at the front of the frame when he pre-assembled it to check the fit. I found that they felt tight, but were not all the way in. It seems the holes in the frame were so close to the screw size, that a little bit of the CF got into the threads causing them to bind going in. No big deal. I removed the spacers and ran a 3mm round file through the holes in the frames sides to clean them up, then ran a 3mm tap through the spacers to clean them up too.

When installing the OW shaft, it fit perfectly up through the 2 lower bearings, but was just a bit tight pushing it up through the bearing in the motor mount. Not wanting to put any side stress on the bearings, I had to elongate the mounting holes for the motor mount about 1/2mm toward the rear to get a nice smooth fit of the OW shaft.


I would attribute both of these minor adjustments to the fact that the bolt holes in the frame sides are exactly 3mm which leaves no room for movement of the parts during assembly which is actually a good thing. Very precise indeed.


I also had to file down the height of the provided brass spacer that goes below the front gear as the gear was slightly too high for the grub screws to fit into the "indents" in the OW shaft.

Now, keep in mind that I am certainly not complaining about a few very minor adjustments. I just wanted to mention them as I have Scott's first frame and he asked me to share any issues that I might have had with it.

I mounted the Z30-1100 motor that I got from Bill, and I can say that the EZ-Mesh motor mount is the shiznit. Took 30 seconds to set the gear mesh.
I installed a complete Gaui CNC head assembly since I got it at half price. ;D I mounted the cyclic servos and then set the head up for 0 pitch at mid stick using Trex 600 32mm link rods on the cyclic servos with the links at 47mm center to center. Due to the servo placement, the elevator servo must be mounted first, and is a very tight fit against the left-hand cyclic servo.

I mounted the tail boom and put the rudder servo in the frame to check fit and operation of the control rod for binding. It all fits and works fine, however I may have to move the rudder servo to the boom to get the CG right for the lipos I am going to use.

I haven't set the swash mixes in the radio yet, or the final tail set-up since I might move the rudder servo. I am still fiddling with the final electronics placement although I have most of it temporarily strapped in place, except the bec, which I haven't installed since I was doing the set-up with a 4.8volt flight battery.

Pics to come soon. I just haven't been able to find time to put them on my computer.

Overall, this is an awesome frame, and a huge improvement over the stock Gaui plastic and CF frames. I can't wait to get it in the air.
Next up will be a complete rebuild of my 425 with a HeadHunter frame. Yep, it's that nice, and well worth it.

Kudos to Scott on a great upgrade for the Hurricane 425/550.

[dunkonu23]

Thanks, Jerry! I'm happy you like the frameset. I've got some new metal parts being shipped this week sometime. I think they're the bearing blocks.

CG is an issue. I had to move my tail servo to the boom, as well. And, I had to move the ESC to the side of the frames--I went from an ICE 75 to an ICE Lite 100 just for that reason. Right now, with 3300 mah batteries from Hyperion, CG is dead on. The thing I'm looking at is lighter batteries so I can get more adjustability in CG. Right now, top on my list to try out are Volt's 3300 35 C 6S packs. They're lighter than the Hyperion packs and are rated identically in terms of output....cheaper, too. Downside to the Voltz is this: Virtually no warranty.

Can't wait to see the pics, bro!

Scott

[Doozer]

Can't wait to see the pics Jerry. I've got an engine and some servos to buy this payday, but next payday I'm going to send scott some money. I should be building in a month or so... I hope .

[Jerrymac]

Well guys, I am still tinkering around with electronics placement, so no new updates yet. I made a "mock-up" of the Voltz 6s 2600 battery and came out a little tail heavy, so I made one of the 6s 3300 and came out nose heavy.

I think I am going to just check out the weight of some other batteries before moving stuff around again. Most of the 'cheaper' batteries seem to be heavier than the Voltz, so I might try a cheapie 2650mah and see how it works out. I have moved the esc and rudder servo 3 times now and getting a little tired of fooling around with the CG. It is no fault of the helicopter itself, just would be nice if somebody made a decent 6s 3000mah lipo as that would probably be perfect.

I know there are some cheap 6s 3000mah lipos, but most of those are actually heavier than a good brand of 3300mah. I also think that if I was using the long boom the 3300's would be just right, but, this is my 'medium boomed' build. In my short boomed 425, 2500's work out just right, and in my long boomed 550 3300's work just right, but can't seem to find that "perfect" battery for the medium boom.

[dunkonu23]

I thought that too until I went to the ICE 100 and mounted it on the frame outside left right under the main shaft. My CFG is DEAD ON withi the Hyperion batteries. That's why I was thinking Voltz batteries for weight and to get the battery away from the motor. Unfortunately, today with my first Voltz purchase for my Furion 6, one of the Voltz 4500 45C 5s batteries developed one cell ridiculously low and the other borderline, either way, it won't completely charge after 3 hours on the damn thing. 4.07 volts after charge current started to decrease, then at .3 AMPS after three hours only got up to 4.17 volts. Normal for this pack is 4.20 volts per cell. So, if you get voltz batteries, remember to test them before your 7 day warranty expires. I was lucky, I disovered this at 6 days in.

More on CG.. where do you have your ESC mounted, bro? Receiver? Sats? What length boom? I'm asking all this for the knowledge base.

Scott

[Jerrymac]

Ha, I have moved the electronics around so many times I don't remember what I had where to start, but I'll let you know where they end up.

I am using the medium sized boom with 522XL belt on this build, and 500mm blades. My short boomed 425 balances good with 2500mah batteries, and my long boomed 550 is good with 3300mah batteries, so I think I need to just weigh those and get something in-between weight wise then go from there.

For a minute, I thought I had it figured out, but, doh, I forgot to put the canopy on which weighs 86grams and hangs out pretty far on the nose.

[dunkonu23]

This is the battle I fought when I first got my HeadHunter. I ended up putting ballast in the rear. I know it sucks, but I have that huge Scorpion motor and at the time, a Castle Ice 75. When I went to the ICE lite 100, no more ballast and no more CG issue. I use the sideways hold by the grip method.

Scott

[Jerrymac]

Well, I got a few new pics, but forgive me for the poor quality, a photographer I am not, plus it was kinda dark in the basement at 4:00 am, lol. I have all the electronics installed for now, and all the set-up and radio programming done. The only thing I am going to change later is to remove the rx battery and run off of the main pack.
I set it up this way for now to get the proper weight in the nose for the packs I am going to use. The 6s pack in there now is from my plastic framed 425, but the CG works good with that and the 3s 1000mah rx pack in there too.
That gave me a real good idea of what size battery I can use for just a single 6s for all electronics.
The only thing left now is to splash some paint on the unfinished Fusuno canopy that I am going to use, and paint the fins, and tidy up the wiring a little bit.

Weather permitting, I might try to take her out for a test flight this weekend. I just need to change the main blades. I used some woodies for the set-up, but intend on running CF blades on it since I don't trust the wood blades at 2400 head speed.
Whew, sorry for the long winded post. Will take some better pics when the paint is on and a nice day.

Oh yeah, probably can't see it too well in the pics, ( they are white) but I used 2mm plastic nuts and bolts to mount the landing gear, that way in a crash, hopefully it will shear the bolts off and not damage the CF frame.

[9sec240]

Nice clean install Jerry. I wonder if you moved the balls in on the cyclic servo arms one hole, your swash linkages would be closer to 90° but would still have the travel you needed? How close are you to the factory default of 60% in the swash mix?

[Jerrymac]

I thought about too Ivan, but right now with +- 11 degrees pitch I had to set the swash mix at 75%. The balls are at 17mm from center right now. I might try moving them in one hole just to see what happens.

[dunkonu23]

Jerry,

Nice job, bro! I know you've got issues with the total collective. If you look closely take a close look at the lower tail drive gear. It is up a bit. It may give you more clearance. Also, think about trimming the back half off the elevator arm. It may hit the gyro tray.

Here's another thing... I also used the rubber grommets on my servos to mount them. I used the brass inserts, as well. That will help out with the angle you have on the arms. Mine are slightly tilted but not as much as yours.

Scott

[9sec240]

I would say if the servo arm does not get past 45° in its travel, you should be good to go.

[dunkonu23]

That's true, but Jerry has the other end of the arm hitting on the upper tail drive pulley. Looking at the angle, it looks pretty equal to me.

Scott

Attachments:

[Jerrymac]

Thanks for your thoughts and suggestions guys.
A couple things I might mention. I PM'd Scott regarding an issue with the elevator servo arm hitting the top of the tail drive gear at full neg pitch and full back elevator, so that was something that Ivan was not aware of until Scott just mentioned it in his last post.
Also, Scott, I was not able to use the rubber spacers and brass inserts when mounting the cyclic servos. I realize that all servos are not the same exact size, but with the DS821's that I used, you can see in the pic of the left side that the cyclic servo and elevator servo are actually touching each other now.

I am going to try to make a few adjustments here and there and see what I can come up with. Thanks again for your input.



EDIT: 3 hours later...... You guys have good eyes, lol, amazing what you can see while looking over a picture, that you can miss while just putting your heli together. I actually noticed in the right side pic that my rudder servo arm is not exactly at 90 degrees, even though I took the time to try to get it perfectly centered.

The tail drive gear/shaft is actually off a lot more than the pic shows. About 3mm of the brass gear is above the main gear, and vice versa. Not sure if this is a Gaui , a HH, a Jerry, or a combination that caused this issue, but I think it can easily be resolved.
I removed the screws from the top bearing block on the tail drive shaft and pushed the shaft down about 3mm, till it was centered with the main gear. This gave me enough clearance that with +-12 collective, and 7 degrees cyclic pitch the unused end of the servo arm did in fact hit the gyro mount before the ball end hit the top of the tail shaft, which was my original issue.
Now, I just need to slightly elongate the upper bearing block mounting holes lower as only about 1/3 of the threads are visible. Then I will have to trim off the unused end of the servo arm so that it doesn't contact the gyro mount.
I might be getting just a little too picky here, since there is almost no chance that I would ever be at full neg pitch and full back elevator anyhow, but, I just noticed the contact issue while checking for any binding.

I am not too concerned about the fact that the servo to swash link rods are at a slight angle at 0 pitch as I have seen this on other helicopters before. At slightly above 3/4 throttle, and slightly below 1/4 throttle the arc of the servo arms causes the rods to become straight, so, no biggie there.

More updates to follow........

[dunkonu23]

Hi Jerry,

Can you measure the servo width and height and get back to me with it. I need to compare that to what I have. Mine are close, but they don't touch. I've used two brands of servos in the setup--Hyperion and Align. Each were different, but the only time I've had the elevator servo hit the the tail drive gear is when I was seeing if I could use a Total G with mine--without a flybar head and it hit at about 15 degrees collective. I'll compare original frames with the frames I had cut and see if there is any difference in servo placement. As of now, the only differences I remember were the canopy mount hole and the positioning of the tail servo.

Scott

[dunkonu23]

Jerry you are da man!

I am disturbed about the bearing thing. I will check it out on the frames I have at home when I get there today.

Scott

[dunkonu23]

I checked a couple of things on the new frames vs the old frames. The elevator servo cutouts are perfect as are the bearing mount holes. Dunno what to say, bro.

Scott

[Jerrymac]

OK, well here are a few servo dimensions, and some other interesting observations. The dimensions on the DS821 servos are, height of case (not including flange)= 38.5mm, width of case= 19mm, depth from front of mounting flange to rear of case=32mm.


Gaui quality control= not too good. I removed the tail drive shaft to compare it with a couple of spares I had, and was pretty surprised at what I found. I have 1 of the 14T steel gear replacement shafts (204577) and it does not even have the hole in the top of the shaft to mount the upper drive gear??? I also have 1 of the stock brass gear replacement shafts and the distance between the top of the shaft and the hole for the upper gear is 2.5mm different???

With the new brass geared shaft installed, the top bearing mount can be installed in the original mounting holes and the brass gear lines up with the main gear and the top of the shaft no longer interferes with the elevator servo arm. Geez, thanks Gaui for all the aggravation. Wonder how people are supposed to use the steel geared replacement shaft with no hole to mount the upper gear to.

Scott, Gaui apologizes for questioning the design of your frames, LMAO.

So now, all I have to do is trim off the unused end of the elevator servo arm, and order some batteries and I am ready to maiden. ;D

I still need to paint the canopy, but that won't stop me from taking her out for a spin if it ever quits raining here.

More updates to follow as they become available...... Hopefully no more questions for Scott.

[dunkonu23]

Jerry,

Ask away! I'm here to help everyone, even staff! LOL!!! I am surprised at the disparity in tail drive assemblies, though. Oh, well. You got it, bro!!! I knew you could!

Scott