Goblin thread for noobs buying Goblins

[rexxigpilot]

Originally Posted by Mystic3D

Lipo's - Such a contentious topic. If you are a noob, you are going to crash, so totally agree on inexpensive Lipos or if you don't fly a lot. In these cases you will never win on either 50% crash replacement or 100 + cycle life. I have yet to get more than 50 flights on HK anything, Nano's, Turnigys, before power loss and puffing, but I fly a LOT, and crash infrequently. So in this case I can easily prove TP is cheaper with 2 year warranty alone.

ESC - I would try the new Scorpion Ver. 5, cost effective, good specs.

The mistake many people make is getting a battery that is only suitable for their needs when brand new. All batteries deteriorate and gain internal resistance as they age and are cycled. If you start with batteries that are say 3 times what you need as far as C rating, they will still have sufficient power after 150+ flights, provided you fly often and don't let age and/or poor storage procedure destroy them first.

For instance, if you fly with 12S, 5000mAh packs and pull 100A peaks, don't go buy 20C packs. They are only capable of 100A max at 20C. Buy 65C pack from the start and even when they lose 2/3rds of their power (65C/3 = 21.7C), they still can provide 108A and are still completely usable for 3D.

If you can afford it, my advice is to buy packs of a C rating that will last for 150 cycles or 2 years worth of flying, whichever comes first. After that point most batteries have lost half their power and at least one cell will start to fail. That's my opinon, YMMV.

Also, don't use the peak C rating when selecting packs, use the continuous rating. That peak number just means the pack won't puff immediately when pulling that much power from it, but it will certainly shorten it's service life.

[Euwan]

Thanks guys for all the info about the batts

[Mystic3D]

Originally Posted by rexxigpilot

The mistake many people make is getting a battery that is only suitable for their needs when brand new. All batteries deteriorate and gain internal resistance as they age and are cycled. If you start with batteries that are say 3 times what you need as far as C rating, they will still have sufficient power after 150+ flights, provided you fly often and don't let age and/or poor storage procedure destroy them first.

For instance, if you fly with 12S, 5000mAh packs and pull 100A peaks, don't go buy 20C packs. They are only capable of 100A max at 20C. Buy 65C pack from the start and even when they lose 2/3rds of their power (65C/3 = 21.7C), they still can provide 108A and are still completely usable for 3D.

If you can afford it, my advice is to buy packs of a C rating that will last for 150 cycles or 2 years worth of flying, whichever comes first. After that point most batteries have lost half their power and at least one cell will start to fail. That's my opinon, YMMV.

Also, don't use the peak C rating when selecting packs, use the continuous rating. That peak number just means the pack won't puff immediately when pulling that much power from it, but it will certainly shorten it's service life.

Good Advice.

My thinking has changed over time. After spending a lot of money on TP Lipos, I thought. If I get over 100 Cycles then I break even on Cost per Cycle(My Metric). Then I started counting every cycle on each pack, 14 Cycles a month and realized it did not matter. At 300 Cycles over a 2 year period which is the warranty period, it does not matter. If one fails, then I sent it in and get a replacement. So in this case the long term cost per cycle is 1/3 of a cheap HK pack. This assumes no crashes which is not a good assumption so lets say 1/2 the cost which is more in line.

So I care about long term cost which might be atypical, but just another way of thinking..

[JTAnimal]

Originally Posted by Mystic3D

Lipo's - Such a contentious topic. If you are a noob, you are going to crash, so totally agree on inexpensive Lipos or if you don't fly a lot. In these cases you will never win on either 50% crash replacement or 100 + cycle life. I have yet to get more than 50 flights on HK anything, Nano's, Turnigys, before power loss and puffing, but I fly a LOT, and crash infrequently. So in this case I can easily prove TP is cheaper with 2 year warranty alone.

ESC - I would try the new Scorpion Ver. 5, cost effective, good specs.

I dont like to see statements like this "If you are a noob your going to crash" I understand what your pont was but i hate to be told im doomed to crash. One year of flying a Trex 500 and 550 and I have not crashed. i spent alot of time on the simulator, i think that is improtant. but you dont have to crash to learn to fly. I push it at times and that alwasy were you will learn more and possably crash. It will be one year in March for me, i can do loops, rolls, inverted, getting better all the time. and i dont think i'm the exception. I'm not putting you down for your poit of view but its not fair to a noob to tell them they are doomed to crash.

If you follow some rulles and take the flying seriously, there is no reason to crash. Some people dont need to fly smack 3D to have fun and as long as your having fun who cares what others think. For most of us this is just a hobby.

[Tronix]

I'm a newb myself and plan on purchasing a goblin. I wonder what's the lowest headspeed possible on a goblin? i've seen it at 1600, but just HOW low can you go?

[Mystic3D]

Originally Posted by JTAnimal

I dont like to see statements like this "If you are a noob your going to crash" I understand what your pont was but i hate to be told im doomed to crash. One year of flying a Trex 500 and 550 and I have not crashed. i spent alot of time on the simulator, i think that is improtant. but you dont have to crash to learn to fly. I push it at times and that alwasy were you will learn more and possably crash. It will be one year in March for me, i can do loops, rolls, inverted, getting better all the time. and i dont think i'm the exception. I'm not putting you down for your poit of view but its not fair to a noob to tell them they are doomed to crash.

If you follow some rulles and take the flying seriously, there is no reason to crash. Some people dont need to fly smack 3D to have fun and as long as your having fun who cares what others think. For most of us this is just a hobby.

Your right, that was not my intent.
I know I will crash, and I expect I will crash. So when it happens, it's no big deal. It's more a mental thing, plan for the worse, hope for the best. Heck, the Pros Crash, Nick Maxwell told me he crashes about once a month.

[windwizard]

Hi everyone thanks for the all the information, although so many varying opinions kinda suprises me considering you all are talking about getting the best componants for a very expensive heli. I guess many good options exist for most componant selections, which is good for the hobby, but is also tough for the new guy.

While I am thinking about it - where in the heck do you buy varios sized pinion gears I dont see them (18-23) toothed pinions anywhere?

Im trying to get this right the first time and have settled on the follwing component combination but before I start spending money I need a thumbs up or down from a couple of experiecned pilots.

(And this might just take a miracle to find two or more people with a shared opinion about my setup good or bad.) LOL



Flight Style: Mild Sport
FBL System: Full size (black) V-BAR 5.2 $319.99
Motor: Scorpion 4035-560 $249.99
Pinion: 16t (stock Pinion 20t = 13.4:1)
Headspeed: 1700 - 1800
ESC: Jive 120HV $539.99
Governor: Jive 120
BEC: Slave/master from Jive @ ( 8.4 ?)
RX Pack: none
Cyclic Servos: Outrage BL9180 (8.4v)$380.00
Tail Servo: Outrage BL9188 (8.4v) $138.00
Main Blades: 690mm Stock SAB
Tail Blades: 115mm Stock SAB
Lipos: 2nd choice Turnigy 35C 6S 5000mah(2) $120.00

Scorpion Motor Bearing Lubrication Kit $5.00

SAB GOBLIN 700 Flybarless Electric Helicopter Kit $1000.00


MISC. COST FOR EXTRAS AND SHIPPING AND TAX $250.00




________________

$3000.00


My Radio is a DX7 (not DX7e)
Do I need satellite RX only to work with V-BAR?
What else am I forgetting or don’t know about?, and will this selection of components work well together?


Thanks for your help,

Wiz!

[Thunder Fighter]

Originally Posted by Tronix

I'm a newb myself and plan on purchasing a goblin. I wonder what's the lowest headspeed possible on a goblin? i've seen it at 1600, but just HOW low can you go?

The limitation will be in how firm the damping in the head is. If it is firm and you reduce the head speed it will start to wobble at some point, this can be cured by going to softer dampers. From a lift perspective you cold fly it at 1000rpm or even lower so long as it was setup right and by using semi symmetrical blades you would be able to fly at very low head speed. There are some people who work on setting up heli's to run on low head speed, I think you will find some info if you look in the Mikado forum as the Logo is a popular choice for doing this with.

//Dennis.

[rexxigpilot]

My Radio is a DX7 (not DX7e)
Do I need satellite RX only to work with Jive 120?
What else am I forgetting or don’t know about?, and will this selection of components work well together?

Yes, you need two satellites RX's with the DX7. They plug into the V-Bar unit. Doesn't matter what ESC you use.

[Scottyb410]

Originally Posted by windwizard

Motor: Scorpion 4035-560 $249.99
Pinion: 20t (stock Pinion 20t = 10.7:1) $ ???
Headspeed: 1700 to 2100


Wiz!

I think you need to revisit the motor and pinion choice.
Check out the motor thread. The 560kv and 20t will be a bit rich for what you are after. The stock pinion is also a 22.

[windwizard]

"The 560kv and 20t will be a bit rich for what you are after."

Sorry I dont get your analogy of motors and pinions to carborator adjustments.

[dani_rose]

I will be going for the same 4035-560 Scorpion Motor, and after reading the manual, the pinion of choice will be 21? My style will be sport/mild 3D so would like to get the right pinion the first time. If the stock is 22, I should be able to get it in the air no problem? Or should I just try to get the 21 tooth pinion?

[Euwan]

Originally Posted by dani_rose

I will be going for the same Scorpion Motor, and after reading the manual, the pinion of choice will be either 21 or 22? My style will be sport/mild 3D so would like to get the right pinion the first time. If the stock is 22, I should be able to get it in the air no problem?

I am waiting for an answer also as this will be my setup

[rexxigpilot]

http://www.goblin-helicopter.com/for...guration-chart

[rexxigpilot]

Here's the typical setup chart from SAB Goblin.

[windwizard]

Ya Im still getting all the facts straight in my head concerning motor kva ratings = to rpms. And headspeed calculations based on motor speed and motor pinions and of course the "implied" main gear ratio on the Goblin with all the other gears and belts working togather, oh ya.... not to forget system voltage selections also.

This is what I think is the right head speed calc. for the Scoprion 4035-560 (if it's 90% effecient) w/ v-bar, Jive 120 and 12 cell 35c batteries... set up for longer flight times for the intermediate sport flying NOOB!


19 tooth motor pinion for a 2000 rpm headspeed
Result for calculation from Heli direct calculator:

Estimated lowest voltage during flight: 40,92
Lowest RPM (due to voltage and efficiency) : 1822

For + performance, keep req. RPM below: 1886
For target performance, keep req. RPM below: 1961
For - performance, keep req. RPM below: 2018


So 2000 rpms = reduced performance with increased flight times using 19t motor pinion.

This was my plan untill some one wise and full of years tells me that I am full of crapola!

Looks like the chart in the previous post bears out my plan - Shew dont want to get this stuff wrong it seems to be what will separate out the boys from the men! LoL

(Maybe on a heli this size there is reason for more or less headspeed for cruising around - I dont know, but 2000 rpm seems like a good middle of the road compromise for power to flight time balance?)

Wiz

[worldofmaya]

At least with the TDR 1900 was more than enough to have fun. I think 99% of pilots doesn't need more than 1800rpm on a 700. It's an electric-only frame and with a good gov, there's a stable head-speed from beginning to end... I remember times when 2200 was a lot for a 600-class machine.
Btw the new Voodoo 400 uses 465mm blades and has a specified max rpm of 2200rpm.
-Klaus

[Thunder Fighter]

Originally Posted by worldofmaya

Btw the new Voodoo 400 uses 465mm blades and has a specified max rpm of 2200rpm.
-Klaus

OT but are you sure that isn't a misprint? The Protos stretch with the same blades has 2800rpm as its max and flys great at 2500rpm as a sports flyer, 2200 is where I do my orientation practice.

Back on topic, I agree, I will have 1950 as my IU2 on the Goblin only for when I want it to sing, otherwise most of my flying will be in the 1700-1800 range.

//Dennis.

[worldofmaya]

OT, no misprint. The old Acrobat SE (replaced now by the V400) was max 2000rpm. Ploechingers models are really light with long flight time in mind. It's not a smack machine but you can do pretty much everything with even lower headspeeds...

[windwizard]

Alright guys I hear ya...this is what this thread is for, to figure out "What the GOBLIN" is going on!!


I found this video (posted below) of a goblin doing 3d @ 1600rpm head speed, I dont know what motor is cranking out the power but the bird seems to fly well at lower rpms.

Hey! sounds good to me, it's got to be a little less wear and tear on everything running things a bit slower so I guess that I'm back to calculaing a different motor pinion for my scoprion 4035-560 - good practice right?

So if the Goblin will fly this strong at 1600 rpm why then push it to 1800?

(It is true that it seems to slog along doing it's 3d flight at 1600, kind of looks like what I would expect a gas helicopter to fly like - dont really know though, haven't ever seen one in flight in person.)

1600 rpm Goblin 3d
[ame]http://www.youtube.com/watch?v=LqbmwYUuxO8&feature=related[/ame]



Wiz