Build Thread - Leviathan Goblin 700 Conversion

[sctholson]

Nice, thanks Tom.

If you wouldn't mind post back up here with your thoughts after you fly with the 26t for a bit.

[ttaylor]

So is this thing dead or going to happen. ??

[ttaylor]

Sorry this post was meant for the Agile gasser thread.

[carey shurley]

Chris Reibert did a review of the Leviathan gas conversion in the latest issue of RC Heli Pilot starting on page 40

very nice, thanks Chris!

[FrankFuss]

Hi Carey,

I thought I would post this here in case it would be useful to others.

I have started building my Goblin 700 Competition Gas Conversion. So far I have built the Goblin transmission and I am working on fitting the clutch stack to the transmission. It is fairly straight forward, but I thought I would just check on the choices I am making and get your feedback.

The two Drive Pulley Flange Washers were of different thickness, 0.102" on top and 0.106" on bottom. The drive belt was ridding at the top of the main pulley, so I moved the thicker washer to the top. The first photo shows the result. I then moved the three shims to the top resulting in the belt centered on the main pulley. The second photo shows the result. This is the configuration I was planning to go with, after I add one more shim on the bottom to get the bearing mounts to line up perfectly with the Clutch Plates.

There are two sets of screw holes for the studs on the Upper Bearing Mount. I was planning to use the innermost set as shows in the third photo, which looks to give the best support between the bearing mount and the transmission.

Regards,
Frank

[rcnut]

I read the same thing and just installed the 26T this weekend.

I have had the tail blow out at 1400 HS with the 27T, but by 1600 it is pretty solid. Due to the big surface of the boom, 115 blades help too.

I read something about that myself, just don't remember where! Getting old really sucks!!!

I bought the 26 tooth pulley a while back, shortly after reading about the lower head speeds and lack of tail authority, and finally installed it. The sound is different, a higher pitch sound. I was having problems with the tail not wanting to turn in faster forward flight, like trying to do piro hurricanes. The 26 tooth pulley helped with the factory blades. However, the tail still wants to resist turning, so maybe longer blades will help.

I have some 115mm tail blades coming (hopefully today) that I want to try next...but not the SAB blades. I was out two Saturdays ago testing out the 26 tooth pulley. After an auto, I spooled up to do it again, but during the spool up, I moved the tail a bit too much and cut up some of the ground, unearthing the grass...oops! Well, that shattered the stock tail blades exposing the foam inside.

So I don't know if my tail issues were due to the blades themselves or the 40+ degree weather I was flying in.

[cruzroy]

ok im installing a wookong h , and in the settings under governor it ask for RPM? and Gear Ratio ?

so i have a goblin 700 comp

so said gear ratio is competition (wider belt) is 7.13:1

but hear is my dilemma, what should i put in for a number for RPM's
and wookong only give a 2 position data, like X.X
and im 7.13:1
so i can only put 7.1 ......., but there is a big diff between 7.1 and 7.13 right....

so i guess i could put 7.9 to 1 would be closet i could get to 7.13
really need help on this......thanks

[Doug Darby]

Put in 7.1 it will be fine.
If you want about 1900 head speed simply put in 13,500 RPM (assuming they want engine RPM)

[Doug Darby]

Put in 7.1 you will be fine.
For 1900 head speed use 13,500 RPM. Assuming they want engine RPM. 13500 / 7.1 = 1901 head speed
13500 / 7.13= 1893 head speed
Imperceptible head speed difference

[Sowa]

Is this the gear ratio input for the gov setup? I'm assuming so.

If your married to the idea of pulling the signal off the crank, then the ratio would be set to 7.1, with the rpm. Because the value is rounded down your actual head speed will vary slightly from the setpoint. i.e. setpoint at 2000 and IRL head speed would be ~1950. In this case you can fudge the setpoint to hit the head speed you want to hold.

The other option is pulling the signal off the main gear which would be 1:1, no rounding required.

[Doug Darby]

Mike is correct in that many of us use a sensor of magnets in the main gear and run 1:1 but there are a few govs that won't let you go that "low". I am not sure about the Woo Kong.

At Aero Hobbies we have set up a couple NAZA H (distant cousin to the Woo Kong) and they were difficult to set up and just not as stable to fly as the "main stream" FBL units...

Best of luck with the Woo Kong,,

[T-bone-1]

pulling mine off the main gear at 1.1 works perfect about 6 gall's now

[Sowa]

Originally Posted by T-bone-1

pulling mine off the main gear at 1.1 works perfect about 6 gall's now

Out of curiosity what gov are you using?

[cruzroy]

i will try it this weekend, im using the stator gator caz bergen says they work well with wookong H. but yes no info on this set up, but im going to try to do as many videos as i can, and maybe you guys will see my $$$$$$$$$$700 goblin hit the ground at 14 lbs 32 feet per sec/sec and that will end my heli flying

i have to say, 2 years ago, when i start thinking about wookong or a auto pilot, i remember videos all over about it, even on DJI website, also there is a dji video with 2 guys building this big gasser with a camera on it, and they explain a few things in ENGLISH, but truth i remember them also bringing that brird out side, both of them carrying the bird to do a calibration, and then a flight test and review......???

WELL????? dji must have a way of going in an deleted the internet files, caz i cant seem to find that video anywhere.......im going crazy thinking that i saw something that wasn't there

well i will continue, i dont give up.........some times.......LOL

but again thanks

[cruzroy]

Originally Posted by Doug Darby

Put in 7.1 it will be fine.
If you want about 1900 head speed simply put in 13,500 RPM (assuming they want engine RPM)

now im a soft flyer......so should i use a lower headspeed.......i dont 3d

[Doug Darby]

You could go with less if you like. Personally my goblin flies nice in the 1800 to 1900 range. Tom flies his as low as 1400 but he is a very experienced builder and flyer. Most Goblins prefer higher head speeds.

[cruzroy]

those toxic 275 zenoah's could push 13000 rpm, guess i got to read up on them

[T-bone-1]

I am flying neo v-bar gov

[LoveToFly1]

Originally Posted by cruzroy

those toxic 275 zenoah's could push 13000 rpm, guess i got to read up on them

LOL - what?!?!?! the motor will push all the way up to 15,500rpm, which is where I run mine at....

[JoeRuscito]

Hey Guys,

Im new to gassers but I think this will be my next build. Although Ill go with the 770 I believe.

Im starting to price it out but maybe someone can save me the time and give me an idea (estimate) of all up cost. I know this can very greatly. Am I correct to think Im looking at about $2500 with motor and electronics?

Thanks