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Ron’s HeliProz South . Century Helicopter . MTA Hobbies

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e-Electric Conversions > Gasser Seaking conversion
 
 
cfranks
Veteran
Location: Adelaide South Australia

If anyone can help, I need some basic advice. I have been building (very slowly) a Seaking using a Century body and Vario Benzin mechanics. Based on a friend's similar conversion of a Vario 300C, I would like to try the Seaking as an electric and need to know how I determine the size of motor & LiPo packs. The heli will use an OF 5 blade head with 670 blade, i.e. a rotor disk of 1500 dia. Motor will have some airflow from the top hole out through the open side door, probably enhanced (if need be) with 12v fans. Model will probably weigh 7 to 8Kg.
First thoughts are an Actro 24-5 with a Kontronic Jazz 55-10-32 'cos they are what my friend is using. Will 10S3P be enough or what? Would appreciate any suggestions.

Charles
05-12-2005 Over year old.
 
 
Peter65
Key Veteran
Location: Roxby Downs, South Australia.

Charles that's a heli I am hanging out to see at the oval.
Good luck with it.

Laughing at yourself will lengthen your life. Laughing at me will shorten it...
05-12-2005 Over year old.
HOMEPAGE  
 
 
cfranks
Veteran
Location: Adelaide South Australia

Thanks Peter, I'll let you know how it progresses. Could be a long time
The 'conversion to electric' thoughts were triggered by a second failure of the electric start on the Bell 47after less than 20 flights . I need to pull the whole heli apart to get at it and I have the same system in the Seaking.

Charles
05-12-2005 Over year old.
 
 
JBajkor
Heliman
Location: Hamilton, Ont. Canada

24-5 is too small. You will need at least Actro32, or Actro 40 series.
Problem with the Actro 40 is a very low Kv, just over 200 if I recall. You will need to have a low gear ratio. I would guess in the range of 5:1 with 13S lipo and a big Shulze esc.
The only other option is to get the wieght down. 8Kg is a LOT of heli!
Joe
05-19-2005 Over year old.
HOMEPAGE  
 
 
cfranks
Veteran
Location: Adelaide South Australia

Thanks for the info Joe. The 8Kgs is a calculated guess based on the current configuration (Vario Benzin mechanics). I am now thinking of using the Actro 60-175, ESC not sure yet, and two of the Maxamps Lipoly 6750mah 5S3P giving 10s3P. The weight of that could be close to the RC230 engine being replaced.
I’m reading a lot of other peoples experiences (virtually all planks) and thinking “that sounds as though it might do” without any idea of how to go about choosing the right motor, ESC and battery. My Seaking will have a 5 blade rotor, disk diameter of 1.5 metre and a head speed of 1300 to 1400. I will drive the main shaft with a Bevel gear pair but will need to drive the tail rotor (another 5 blade device) at about 10 to 15K rpm. The motor will have to give me that speed either directly or geared up.

A small example. I see the motor specs use a figure of xxx rpm per volt so do I assume the motor will run at (batt volts x xxx rpm/v) or do I choose a lower figure. This embarrassing lack of knowledge makes my teeth hurt!

Charles
05-19-2005 Over year old.
 
 
JBajkor
Heliman
Location: Hamilton, Ont. Canada

I'll try give a short version using the Actro 60-175 as an example:
Kv = 175RPM/V
10S under load = 37V
no load speed = 175 X 37 = 6475RPM
actual loaded speed will be about 80% no-load
6475 X 80% = 5180RPM
using 1400 desired head speed: 5180 / 1400 = 3.7
you need 3.7:1 from motor to mainshaft, This ratio is easy to do with belt drive. I would suggest leaving the original gears from main to tail. If you spin the mainshaft at the right speed, the tail will be correct.

Now, if you do the same with 13S, you should end up with 4.81:1 and a motor speed just under 7000RPM.

I don't know the spec for max RPM of the motor, but you will need to check that. 7K must be getting close.

Now on to current.
A rough estimation is 2.5Hp required to hover. (very rough guess, too many factors involved to be accurate) 8Kg would need about 1865w!!!
Hover current with 10S: I = P/E = 1865/37 = 50A
with 13S: 1875 / 48.1 = 39A (much better)

The motor is rated at 85A max so there is a little reserve power, not much. Should be ok for scale flight.

The actual current used will depend on the load and Io spec for the motor. (amps/N/m)

One final note: with Actro, DO NOT use the fiberglass motor mount they provide. Make one from aluminum and include cooling fins. Much of the heat of the wire coils can be removed this way.

Good luck and keep us posted.
Joe
05-20-2005 Over year old.
HOMEPAGE  
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

hey , the 32- 3 or 4 ( heli version ) not the airplane version , the heli version mounts different and in helis runs about 40 degrees cooler , and it will lift it just fine , you dont need the 60 series ,its just way to big , but the 40 series will work better if they make it in the heli version , you can use 2 5s4p since the motor runs efficient.
what gearing is on the heli now ? the esc , is another question , you can run what Im running , 40-160 , or you could get the 32-160 schulze , I would get the 40-160 , that way you have room to bump up the voltage and regear it . conversion are so cool , I have a Fury carbon that i converted, 32-4 , schulze 40-160 , batteries 13s3p , HP around 4 to 4 1/2 , if you get the big schulze , you can dial the headspeed you like and dont have to worry about looseing efficience because the esc can handle 160 cont. amps and 210 peak amps , you last controller you will ever need . 5 blade rotor hear , MAN , sould be nice , whats the pitch range on one of those ? like -2 and + 6 .

Tony

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
05-20-2005 Over year old.
 
 
cfranks
Veteran
Location: Adelaide South Australia

That is real good information Joe/Tony, Thanks alot.
I've got more reading to do now and I'll keep you informed of any progress.

Charles
05-22-2005 Over year old.
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

hey , well did you come up with anything?

Tony

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
06-07-2005 Over year old.
 
 
cfranks
Veteran
Location: Adelaide South Australia

Tony,

I examined all the info I could get and then went and ordered the biggest I could find
Nearly two weeks ago, I ordered a Plettenberg HP370/40/A2 Heli motor plus a Shulze Future 40/160H Controller. They haven't debited my credit card yet so that says they (icare-rc) haven't shipped it yet.

My crude calcs for the motor suggest I can reasonably expect about 11k rpm with 48?? volts so I should be able to mount it directly in place of the RC230 and use the existing Vario belt and idler shaft to Main Gear assembly. That way I get the correct tail rpm automatically.

Haven't thought much about which battery to get but am thinking of a 12S3P in a 2x 6S3P config. I have just ordered a second Astro 109 charger so I can charge both (6S3P) at the same time.

What have I missed or what have I done wrong??

Charles
06-07-2005 Over year old.
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

cool , should be a nice project , you will love the 40-160 , man I sure like my 2 I have

Tony

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
06-07-2005 Over year old.
 
 
cfranks
Veteran
Location: Adelaide South Australia

Tony,

Seems like I have still got a few weeks to wait but, in the mean time....
I hear the 40/160H Controller is a little sparse with instructions. Do you have anything that could be usefull in setting up? Especially in the Governor section. Using the proposed 5 blade (thus flybarless) head, a constant head speed is fairly critical and usually requires a Governor of sorts.

Thx

Charles
06-10-2005 Over year old.
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

no problem , just let me know when you get it , it has dipswitches so its easy once you know what they mean

Tony

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
06-10-2005 Over year old.
 
 
cfranks
Veteran
Location: Adelaide South Australia

I'm still waiting for this stuff! Is it always so difficult to get Contollers? According to icare-rc the delay is with Shulze, they are missing some components for the assembly. I have ordered some Maxamp batteries 6S4P and they will take a few weeks to build. If I had the motor, I could at least try to make all the fittings for it.

Idle Charles
07-01-2005 Over year old.
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

hey , yeh , Germany can get timely waiting on customs , and the motor is another one thats hard to get , German made , great stuff , but small business , once yo get it , dont mess it up , hard to get it fixed too

Tony

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
07-01-2005 Over year old.
 
 
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e-Electric Conversions > Gasser Seaking conversion
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