Bell UH-1

[IAHM-COL]

Looks like he went for trying to put someone down over on the other forum.

Well what did I expect

Don't grasp the meaning here. I'm missing background information.

[bomber]

I guess what I mean is that even after we'd explained the design process we were going to go through. He then went over to the other forum and applied a bit of spin on it to attempt to discredit bell_pilots abilities

[IAHM-COL]

rgr. Well, some people help. Others just try to inflate their own egos.

[bell_pilot]

Ok guys. I ve wasted a lot of my time trying to tell the other forum members that they must take off their "blinkers" to have perspective. I understood i must not struggle with their egos, there is no need and no time for that.
As i said, lets keep pushing forward. I ll say about some more feedbacks tonight.

[bell_pilot]

1.) Is it realistic, when I'm on the ground with zero collective and I move the cyclic that then the helicopter tips over. My understanding is that with zero collective the blade pitch should be at or near zero and therefore there shouldn't be enough thrust to tip the helicopter over.

1) is a good question that I don't know the answer too in the same way as mue doesn't, we've never flown a helicopter or wiggled the cyclic when the collective is in idle.

No it is not realistic. It may bend a little bit and you may feel your cyclic movements while the collective is at idle. But this helicopter tilts over by cyclic easily. Thus, another case is noted to examine.

I would also like to know if there's a jump, like going through a gate when leaving the idle position, or is it a linear progression, I can model either.

Assume as linear progression.

[bomber]

4- a. You said the turbine model is ok. Yes, the rpm stay still. But when you collective up very fast, rpm will drop dramatically at a moment.
b. RPM oscillates around %1 all the time.

I understand English is not your first language and at first I didn't understand what you were after here...

I've gone from the rpm's varying too much to too less.... you actually want the rpm to drop dramatically when the collective is moved very fast.

[bell_pilot]

I understand English is not your first language and at first I didn't understand what you were after here...

I do my best.

I've gone from the rpm's varying too much to too less.... you actually want the rpm to drop dramatically when the collective is moved very fast.

You may reduce P gain.

[bomber]

I know you do...

There is no P gain... It's a lot more complex than that, I'm going to have to rewrite the turbine controls

[bomber]

In the flight control system file within the 'Flight' channel

If you change the code to this

Code: Select all

      <scheduled_gain>
         <input>T4T/one</input>
         <table>
            <independentVar>fcs/collective-cmd-pos</independentVar>
            <tableData>
            -0.6      -5.3
            0.6         6.2
            </tableData>
         </table>
         <output>propulsion/engine[0]/blade-angle</output>
      </scheduled_gain>

It'll stop the helicopter from rolling over when messing with the cyclic in idle.

I don't understand these people that first say your flight model will never be any good then give the reason as being something very insignificant in the overall complexity of the helicopter fdm. And they justify their whole argument on some trumped up accusation that you're ignoring physics.. No I'm not I'm prioritising what's important at this moment in time to fix, so as we can move onto the next problem.

Insulting my flight model, and me as being incapable does not make me want to work with these people.

Even more frustrating is that these people have next to no idea how to work 'outside the box' with jsbsim. They've never done a flight model that doesn't come with masses of wind tunnel data and some haven't actually delivered a 'flight' model and if they ever did they'd call it WIP.... well what do they think this flight model I'm doing is ? Did I ever say it was complete ?

The only comfort I get is that from the quote in my signature, I know Mitchell had to deal with a lot of these types of people as well.

Simon

[IAHM-COL]

If its any "comfort" I think your JSBsims are from the behavior perspective quite enjoyable. The Pup is the most flyable single prop Ive tested so far, and your gliders enjoy good reputation. --fwiw, I dont experience that myself, and I dont fly without at least one engine--
Best,