Request for Information

[Nitrospazzz]

As some of you know I have started a information blog on aerial photography. I currently have some information on lifting capacity of helicopters but it is based on a few hours of searching this and other forums.

What I would like is some input from you guys/gals. I would like to know how much you are lifting, the max amount of weight you have flown at and helicopter setup. If you have done testing with different weights under your heli thats what I'm looking for.

Currently I have the weight capacity post pretty basic, I would like to eventually have a post for each weight class or blade size. Ideally each blade size would have a few setups that we know work for lifting a given weight. This information will be available to everyone and should prove helpful to those getting into AP or thinking about making a purchase of another helicopter.

I am also working on a data table for all the mounts available on the market and awaiting feedback from the manufacturers. I currently have Airfoil Skycam, Helicam Solutions and AskmanAP. If you make and sell mounts let me know and I will add you to the table.

You can view the blog at www.rcap.info/blog.htm

Thanks ahead of time.

[GGoodrum]

I think you might be a bit light on the AUWs for the various sizes. For instance, my Logo 10 setup weighs 9-1/2 pounds and it has plenty of reserve power. Also, many here are flying 12-pound Raptor setups with no problem. With today's more powerful motors and better batteries, here's the limits I would use:

TRex/Mini Titan (335mm blades...): 3 lb.
QJ-8/Lepton (420mm): 7 lbs
Acrobat SE/LA Sniper (470mm): 9 lbs
Logo 10 (500mm): 10 lbs
Swift/e550/stretched L10: (550mm): 11 lbs
Logo 14 (580mm): 12 lbs.
L20/stretched L14/TRex 600/etc. (600mm): 13 lbs
eTitan Conversion/e620SE (620mm): 14lbs

-- Gary

[Menno]

With today's more powerful motors and better batteries, here's the limits I would use:

Gary,

Are the weights you specified the maximum lift or the maximum AUW with save auto capacity.

14 lbs AUW with 620mm blades would be pushing it with an auto.

[miami6]

What is the Save auto capacity ?

if I take gary's number -- eTitan Conversion/e620SE (620mm): 14lbs ---

My Rig
Underslung RTF with the DSLRbody ,Wide 14mm Lens - Servos , Receiver, Switch,Voltwatch,Downlink , Regulators, And Battery system is 7.45 LBS

[Cryofix]

To be honest I think there is a huge drop off in percentages of sucessfull autos when you add even smaller amounts of weight to the heli, when you approach double the the weight of a helicopter you pretty much bring your chances to a slim 5%, given your situation already (doing aerial shots in confined quarters) there is even less of a chance.

here is my assumption of safe auto percentages, the percentages are the based on the helicopters weight:

10% weight 92% chance to Auto
20% weight 80% chance to Auto
30% weight 60% chance to Auto
40% weight 50% chance to Auto
50% weight 40% chance to Auto
60% weight 30% chance to Auto
70% weight 20% chance to Auto
80% weight 15% chance to Auto
90% weight 10% chance to Auto
100% weight 5% chance to Auto
110% weight 0 % chance to Auto

[MLaBoyteaux]

I would think a formula for weight/disc area might be a better indicator of auto-ability than percentage of the helicopters "dry" weight, wouldn't it?

Kind of like wing loading on airplanes. the higher the wing loading, the more inclined it's going to glide like a brick. :lol:

[Cryofix]

I agree Mark, this is pretty much assumption based on out of the box helis, your chances will improve but not dramatically with larger blades, unless you go from 500 to 800's

[LoopBaCK]

Blake,

Very good page with great information. I can tell you've worked hard to get such a variety of information into one place. Sure wish I could've found such a page when I started! Very helpful...

[Nitrospazzz]

Thanks for the information guys, I'll be updating the site shortly...hopefully today. Right now I have it all in excel and I'm trying to find a way to calculate safe lift given a given blade length. I've got a very basic formula that is surprisingly close if you plug in values but the problem is it doesn't take into affect altitude, wind, temperature and the hundred or so other variables we deal with. I'm going to clean it up a bit and run it by my engineering statistics teacher and see if he has any ideas on how to better evaluate the data.

My goal would to have an equation where you enter blade length, altitude and hover RPM and it spits out a safe flying weight. Or maybe the other way around, you say you want to lift 12.5 pounds worth of gear and it gives you a minimum blade length for the job.

If anyone has the formula for calculating lift in a HOVER it would be greatly appreciated. I've spent a few hours on google and haven't found anything really useful. Calculating it in forward flights a breeze but a hover throws a few problems into the deal.

[AZ ChopperCam]

My goal would to have an equation where you enter blade length, altitude and hover RPM and it spits out a safe flying weight.

For your altitude variable find density altitude first then use that number and the rest will fall into place. Flying 12lb on 680's on a standard day will be much different than a hot, humid, low pressure day

Not as much of a problem with the guys at near sea level but for anyone over 3000' it starts to play big

[oscillator]

DJ is right, you want to base the formula on Density Altitude. All aircraft performance data that I have ever seen is based on Density Altitude - and this is one of the first things you learn as a Pilot for computing takeoff distance with a given airplane.

So you would have density altitude vs blade length to get an idea of lifting capacity. Of course airfoil shape will play a factor, but I assume most of the blades we use are symmetric and have a similar shape.

[Nitrospazzz]

Density Altitude...why didn't I think of that. Guess I don't fly enough, time to find my pilots manual. Thanks