First step into scale and in need of a larger apartment...

[jtcrowder49]

Hello all, I have come to aquire a few components and I'm looking for comments and suggestions from the scale vets out there.

I have one Martin Söllner Bell 47 kit that has never been assembled. It did come with the gas engine. However, I would like to convert this to an electric set-up if possible.

Here are a couple pics of everything testing together.

Let me know what you think!

[goodhunting]

really nice helicopter. Everything is possible... you just need to decide what equipment you need to get the head speed you want...

what is your gear ratio and what size blades do you have on it?

gh

[jtcrowder49]

Originally Posted by goodhunting

really nice helicopter. Everything is possible... you just need to decide what equipment you need to get the head speed you want...

what is your gear ratio and what size blades do you have on it?

gh

I will have to count the teeth to determine the gear ratio. I can not find any info on his site.

The blades were supplied by Söllner and came with everything else. Tip to Tip is right at 3 meters when assembled on the head of the machine.


A little more info:

4 servo swash setup: I have never encountered this, however, I am looking forward to it. My DX18QQ does allow for this I believe.

Tail Drive: This machine has a torque tube that runs inside multiple rubber grommets (spacers?). I feel this isn't necessary, and causes excess drag on the system. I would like to look into replacing these with bearings, unless you guys think otherwise.

[goodhunting]

Before you do anything with the TT supporters check if there are no bearings within the rubber grommets.

Yes the DX18 should support the 4 servos swash mix. Will you keep the flybar or change to the flybarless? If so you need to pick a flight controller that supports the 4 servos swash ... I do believe that most do anyway but it can't hurt to check before you spend your money.

Gh

[jtcrowder49]

Originally Posted by goodhunting

Before you do anything with the TT supporters check if there are no bearings within the rubber grommets.

Yes the DX18 should support the 4 servos swash mix. Will you keep the flybar or change to the flybarless? If so you need to pick a flight controller that supports the 4 servos swash ... I do believe that most do anyway but it can't hurt to check before you spend your money.

Gh

Thanks so much for the help.

I will check for the bearings as you have advised.

I will be keeping the flybar for now.

I also need to look into motor mounting options for this machine. Söllner does sell an electro mechanic set up. I emailed him a few days ago and got a response but it seems he didnt understand what I wanted, although his English was good.

Right now I am trying to get a list of things I will need to know before purchasing electronics. Such as: servo torque, how many channels, electric motor kv and watts, gear ratios, and such.

If i can get everything together and in flying condition I may stray from the electric motor at first and throw the gas on. Its my goal to have a very scale flying machine. I already posses the batteries and charge station to power the beast, however, if it sounds better with gas thats what I want.

I know I want to run HV servos and electrionics from Li-ion batts. Those have always seemed easiest to me.

EDIT:

More progress...

I have found the specs on the motor belt and pulley system that runs from the original gas engine to the first pulley in the 2 stage drive.

Pulley Selection

Link will not work as I had planned... The belt that came with the kit is 425mm in circumference, 5m pitch, and 15mm wide. There are a few pulleys available from the site I posted. I will count the teeth on the main gear and pinion and let you know how that goes. -J

EDIT:

I figured out all the gearing info.

Bottom Silver pulley: 48t
Pinion: 19t
Main Gear: 100t
Tail large (Main Pulley):60t
Tail Pinion(TT gear) :13t

[jtcrowder49]

Ok, ecalc has me so confused. Getting 800amps at max motor output! That can't be right... Can anyone help me find a suitable main gear size for these calculators?

Aiming for 700-800 head speed.

[jtcrowder49]

Last night I completely disassembled the mechanic and removed all the surface rust that was covering the flybar and pitch links. It looks quite good if I do say so myself. I have also opted to use the gas engine to start with and get flying. After I see how it handles I may switch over to electric before it gets painted if that is decided.

Ron Lund at Ron's Heliproz has advised me that at least 250 ounces of servo torque would be a good starting point. He's sending us an email and I will inform of the outcome.

[jtcrowder49]

Starting assembly after cleaning the mechanic.

[goodhunting]

wow this thing is huge...

gh

[jtcrowder49]

Originally Posted by goodhunting

wow this thing is huge...

gh

I have the tail almost fully assembled for a test fit. Ill put a measuring tape on it and post a few more photos.

Pics are coming...

I have been scratching my head for the last 2 hours trying to find a way to control the tail rotor pitch. I need a bell crank for sure but haven't found anything I think I could use. Any help would be appreciated.