Free Flight, Free Speech

https://discord.gg/dwcfUDf

I'm doing some JSBsim helicopter development if anyones interested in joining in.

regards

Simon

I'm joining
This is of interest to me. I think I had never seen a functional helicoper with JSBsim, and since I dont understand enough of FDMs, I never figure what are the issues that make this so much a challenge.
That being said, I am probably not the most useful voluntary, but I am up to learn something.

Quick caveat. No discord for me. I can't agree with their licensing. I'll be continually accesible on this forum, thou.

Best,
IH

Conventional thinking of flight simulation is to model stability, lateral and longitudinal... once you've got this, adding a bit of lift and drag with a thrust element and you've a flight model good enough to give a plane designer the nod to understanding if what he's designing is fit for purpose.

A helicopter is massively unstable and has no lift generating wings. Once this has been taken away you're left with a bit of drag and some thrust which a conventional approach using JSBsim, a flight model it does not make.

On the up side there is only 2 things to think about.... thrust and drag.... how hard can it be ?

IAHM-COL wrote: I think I had never seen a functional helicoper with JSBsim

Alouette-III

A helicopter is massively unstable and has no lift generating wings.

True that.

Once this has been taken away you're left with a bit of drag

A bit of drag? Like lots of bits? The helicopter image that comes to mind is rather boxy in appearance, so in the direction of airflow, isnt that body shape generating significantly more drag than the typical airplane looking airflow would?

and some thrust

Yes. But I'm completely unsure where is that thrust coming from, as the blades are located (In the helicopter I'm imagining) above the body.Is that quite like an engined aircraft with forward propelling thrust??

More importantly, in the absence of lift, how can these thing fly? and even be able to hover, VTOL and practically sustain in the air still?

how hard can it be ?

Hopefully not so hard for you.
In my hand every attempt at messing AERO parts of the planes result invariably in an object literally unable to fly.

I got a vehicle....it's 14,000lb... so to oppose this I need 14,000lb and some of thrust from the rotor

I've got no velocity, so very little dynamic pressure and as drags is a product of V squared, in reality very little drag.

Unlike fixed wing aircraft I can't see drag being a limiting factor, unlike the vectorisation of the thrust produced by the rotor into lift and directional propulsion.

bomber wrote:I got a vehicle....it's 14,000lb... so to oppose this I need 14,000lb

lift

bomber wrote:and some of thrust from the rotor

Yes; I think so. You'd need 14000lb+ lift some in order to actually hover. But no lift, as in zero, then your vehicle should be doing no flying at all. Or I am missing something large. (like 7Tons large).

I've got no velocity, so very little dynamic pressure and as drags is a product of V squared, in reality very little drag.

As you hover, on a windless condition, yeah.
But if you hover and there's a wind component, drag will creep up on us squaredly. And if we decide to take the cube-looking object for a joy ride then we might have a hundred or so knots of airspeed. And with the lack of any aerodynamic shape, shouldnt the drag be higher than that found in an sleek looking airfoil? (think a glider)

Unlike fixed wing aircraft I can't see drag being a limiting factor, unlike the vectorisation of the thrust produced by the rotor into lift and directional propulsion.

This I dont understand yet.

all that you say about drag with increased velocity is true....

We'll see what we'll see.... I'm just not expecting drag to be earth shattering to the flight characteristics, unlike on a fixed wing.

Does anyone know if on a twin turboprop helicopter if the engines are contra-rotating ?

by this I mean, 2 engines, 1 rotor.

Another question.... I have a HOTAS

I envisage using the yoke\joystick for the cyclic control.....

The collective however I see being controlled using the throttle....

How are existing helicopters in FG set up ?