Scarlet stripped, how low can we go?

[Jens Jakob Thorsen]

Hi guys.

I have an Epic, but I am contemplating buying a used Scarlet and stripping it down to an absolute minimum weight, to use on an UAS(Octocopter)

Im talking, hacking, sawing and drilling....Did anyone try this?

What is the weight to start with?

Thanks

 

[Mike Garrick]

There was a thread about this a very subject a long time ago in the Scarlet section. We where discussing ways of stripping it down for a lightweight Octocopter rig.

I'll try & dig it up !

 

[Jens Jakob Thorsen]

Thanks!

 

[Björn Benckert]

I think that if you run it of the copter battery and use a low weight mount and lens (the FD mount's on ebay are the lightest, as far as I know) and the FD lenses are also extremely light. Then off course you can take of the metal casing on the side and such, but I'm not sure I would go that far since buying a bigger copter or stronger motors and is far easier and less costy than hacking the camera to pieces.

A copter does not fly well with overload. So if you are close to the limit for being able to take off then it's better to get a bigger copter.

I have ours for sale, if you are interested. It can lift with a scarlet no problem even though I find the droidworx gimbal to be far to flimsy for the load.

 

[Jens Jakob Thorsen]

I think that if you run it of the copter battery and use a low weight mount and lens (the FD mount's on ebay are the lightest, as far as I know) and the FD lenses are also extremely light. Then off course you can take of the metal casing on the side and such, but I'm not sure I would go that far since buying a bigger copter or stronger motors and is far easier and less costy than hacking the camera to pieces.

A copter does not fly well with overload. So if you are close to the limit for being able to take off then it's better to get a bigger copter.

I have ours for sale, if you are interested. It can lift with a scarlet no problem even though I find the droidworx gimbal to be far to flimsy for the load.

I have a canon ti mount and will run it from the copter, but we have a 7kgs limit in Denmark. Im trying to go under that, but as you say the load gets too heavy and the gimbals too weak...12kgs is doable, but the we need permits for every shoot..

Anyway the authorities have invited all pro UAS-user to a meeting to hear and meet their demands, so it may get easier...

 

[Robert Hart]

Firstly, please ignore my wild imaginings which follow, except where they may prompt you and other commenters to alternative thoughts. There are better and more qualified people than I to comment here.

　
I am not sure I would want to look for fat to excise from the case structure. Except for the cooling duct which I have not been able to climb inside and check out, it seems that most of the loadbearing structure is flat form secured by screws.

It is a perfectly valid construction method and would have been given a good workout by RED's R&D with a view to reducing unwanted weight before being turned loose in the world.

It is a method which already has inherent weakness compared to curved form used in the upper structure of the Red One. It also relies very much on the fasteners staying put. Remove too much material from around the fasteners and corner structure will fail near them.

You might be better served by remaking the casework from scratch in magnesium alloy or having RED put the material through their production line. They might be persuaded to make substitute casework for you in fibre re-inforced resin material for a suitable fee. I understand they may have done it previously.

The downside of magnesium alloy would be that in the event of stacking your flying machine, the chance of a LiPo battery fire is pretty good. Your camera would burn to the ground as magnesium burns quite nicely.

To fly the camera, you might be able to lose some fat by removing the fan and top cover. The firmware may not allow you to operate the camera with a fan missing. RED might be persuaded to write you a hack firmware to enable this. The amount of airflow you will get from your octocopter may adequately compensate for the missing fan. For on-ground cooling, a small computer fan on a clip-on device would replace its own fan.

I would not try for any weight reduction by milling away any of the internal heatsink/airduct. It looks to me to require all its metal mass to pass heat and relay structural loads from the front panel to the casework.

You might be able to lose some fat from the lens mount retaining ring by eliminating handles and lugs, instead using radial holes and a removable pin to rotate the lens mount ring to security.

Provided you leave a rim and diagonal load paths from the screwholes to the lens receiver, you might be able to mill quite a bit of material from the lens mount itself if you are unlikely to fly heavy telephoto lenses.

There might be some weight to be saved by using the front panel as a method of mounting the camera, via maybe a modified lens mount. Then remake the bottom panel without the mounting holes, thinner and lighter. You may need to leave corner-to-corner crossover stiffeners in this replacement bottom panel.

I would be tempted to pendant-mount the camera using the four lens mount fasteners and upper airduct cover attach screwholes. Lightened side panels or replacements will carry less mechanical load by this method. If you intend to remove material by cutting out entire sections, you likely may need to cover the holes with metal foil for shielding against RF interference interacting between the camera electronics and the flight computer in the octocopter.

I assume you will power the camera from your octocopter motor power source. There might then be some available weight savings on the rear plate.


My final thoughts. Rather than ruin a perfectly good Scarlet camera, my personal preference would be to remake as much of the octocopter and Scarlet casework components into combined structures as possible. and move the Scarlet electronics across. Otherwise you may be just gnawing at the edges in trying to lose weight.

 

[Jens Jakob Thorsen]

Firstly, please ignore my wild imaginings which follow, except where they may prompt you and other commenters to alternative thoughts. There are better and more qualified people than I to comment here.

　
I am not sure I would want to look for fat to excise from the case structure. Except for the cooling duct which I have not been able to climb inside and check out, it seems that most of the loadbearing structure is flat form secured by screws.

It is a perfectly valid construction method and would have been given a good workout by RED's R&D with a view to reducing unwanted weight before being turned loose in the world.

It is a method which already has inherent weakness compared to curved form used in the upper structure of the Red One. It also relies very much on the fasteners staying put. Remove too much material from around the fasteners and corner structure will fail near them.

You might be better served by remaking the casework from scratch in magnesium alloy or having RED put the material through their production line. They might be persuaded to make substitute casework for you in fibre re-inforced resin material for a suitable fee. I understand they may have done it previously.

The downside of magnesium alloy would be that in the event of stacking your flying machine, the chance of a LiPo battery fire is pretty good. Your camera would burn to the ground as magnesium burns quite nicely.

To fly the camera, you might be able to lose some fat by removing the fan and top cover. The firmware may not allow you to operate the camera with a fan missing. RED might be persuaded to write you a hack firmware to enable this. The amount of airflow you will get from your octocopter may adequately compensate for the missing fan. For on-ground cooling, a small computer fan on a clip-on device would replace its own fan.

I would not try for any weight reduction by milling away any of the internal heatsink/airduct. It looks to me to require all its metal mass to pass heat and relay structural loads from the front panel to the casework.

You might be able to lose some fat from the lens mount retaining ring by eliminating handles and lugs, instead using radial holes and a removable pin to rotate the lens mount ring to security.

Provided you leave a rim and diagonal load paths from the screwholes to the lens receiver, you might be able to mill quite a bit of material from the lens mount itself if you are unlikely to fly heavy telephoto lenses.

There might be some weight to be saved by using the front panel as a method of mounting the camera, via maybe a modified lens mount. Then remake the bottom panel without the mounting holes, thinner and lighter. You may need to leave corner-to-corner crossover stiffeners in this replacement bottom panel.

I would be tempted to pendant-mount the camera using the four lens mount fasteners and upper airduct cover attach screwholes. Lightened side panels or replacements will carry less mechanical load by this method. If you intend to remove material by cutting out entire sections, you likely may need to cover the holes with metal foil for shielding against RF interference interacting between the camera electronics and the flight computer in the octocopter.

I assume you will power the camera from your octocopter motor power source. There might then be some available weight savings on the rear plate.


My final thoughts. Rather than ruin a perfectly good Scarlet camera, my personal preference would be to remake as much of the octocopter and Scarlet casework components into combined structures as possible. and move the Scarlet electronics across. Otherwise you may be just gnawing at the edges in trying to lose weight.

Wise words indeed... It may only be possible to shave off 400-500 grams..And it will never come in under the 7kg limit. Better to seek dispensation from the governing body and use at 10-12kg copter