helicopter plus turbine generator

bomber
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helicopter plus turbine generator

Postby bomber » Fri Oct 25, 2019 8:12 pm

https://discord.gg/dwcfUDf

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

regards

Simon
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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IAHM-COL
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Re: helicopter plus turbine generator

Postby IAHM-COL » Sat Oct 26, 2019 11:58 pm

I'm joining :D
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
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bomber
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Re: helicopter plus turbine generator

Postby bomber » Sun Oct 27, 2019 11:32 am

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 ?
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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Re: helicopter plus turbine generator

Postby 123apple » Sun Oct 27, 2019 6:00 pm

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


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Re: helicopter plus turbine generator

Postby IAHM-COL » Mon Oct 28, 2019 4:23 pm

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.
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Re: helicopter plus turbine generator

Postby bomber » Mon Oct 28, 2019 6:52 pm

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.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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Re: helicopter plus turbine generator

Postby IAHM-COL » Mon Oct 28, 2019 7:19 pm

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.
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If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

bomber
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Re: helicopter plus turbine generator

Postby bomber » Mon Oct 28, 2019 7:38 pm

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.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber
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Re: helicopter plus turbine generator

Postby bomber » Mon Oct 28, 2019 8:01 pm

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

by this I mean, 2 engines, 1 rotor.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber
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Re: helicopter plus turbine generator

Postby bomber » Mon Oct 28, 2019 10:49 pm

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 ?
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell


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