Beagle Pup Development [crossposted]

[bomber]

With regards the engine.... are we all know using the same or very similar file ?

[sanhozay]

The numbers in my engine are out of the manual, including minmp and maxmp. See page 109:

http://www.culvercadet.com/manuals/C85_ ... manual.pdf

Where not specified in said manual I used JSBSim defaults as listed in http://jsbsim.sourceforge.net/JSBSim/cl ... iston.html

Idle speed is supposed to be 500rpm but I had to drop it to 400 to get it to idle in spec (500-600rpm).

The section entitled "Advanced Parameters" is my tuning and bsfc, ram air and volumetric efficiency are quite different from what you had.

JavaProp files are in the Resources directory but, as you might not be able to open that with the applet, I set the pitch to 17.8* and adjusted the chord for a static RPM of 2350. Your airfoils might be different.

[bomber]

Will cross-check, make any changes and then do a static engine test....

[sanhozay]

I've corrected my erroneous htail/vtail areas, run the parameters back through Aeromatic++ and tuned the drag to maintain the same performance as 0.26.0. I haven't done a lot of testing and overall the feel is similar but I can see that the tendency to blow over is somewhat reduced and the onset of stall is not quite so dangerous as it was.

For the curious, I've also added a load of tuning coefficients in fdm/jsbsim/tuning. Apart from parasitic drag, these are all set to 1.0 so this is an off-the-shelf Aeromatic++ FDM.

Pushed to FGADDON as 0.26.1:

https://sourceforge.net/p/flightgear/fgaddon/2318/

[KL-666]

This subject is really hard to follow in two threads. Especially catching up with the latest versions. Can there not be a place, like the first post of either these threads, where the latest versions of all three are published and updated consistently?

Anyway, i found the latest of Sanhozay and Richard.

Sanhozay's model flies really exemplary now. I do not have anything to complain after a quick test.

Richards model got rid of the insane pitch behaviour. This makes it very controllable, which is a great step forward. Yet pitch neutral after input gives a bit of a clunky ending of pitch movement. Another thing is stall speed. In landing i could not fly below 70 kts. Below that i started to sink through (loose lift fast).

You guys should try the pitch test i like to do. From trimmed level flight, pull or push the nose 20 (or 30) degrees, and let go of the controls. I think the behaviour of Sanhozay's version is most correct: Smooth ending of pitching and returning to level pitch due to speeding up when going down, and slowing down when going up. Richards model does the same, but ends the pitch movement when neutral stick at the top or bottom of pitch a bit clunky.

Bombers model i could not try, because i could not find a new model anywhere in all the different threads.

Kind regards, Vincent

[sanhozay]

This subject is really hard to follow in two threads.

Yes, it has got a bit confusing. This is supposed to be my development thread for the Beagle Pup. As such it is just as likely to have updates about the electrical system or new instruments as FDM work. The other thread is the "experiment", i.e. comparing Richard's approach using Aero VSP vs Bomber's component approach. I've drifted into that with a third approach using a basic Aeromatic++ FDM.

Bomber's FDM should be here, started with "T4T-pup100" as the aircraft, but it may not be up to date with his latest changes from this weekend:

https://github.com/FGMEMBERS-NONGPL/Beagle-Pup

I do not have anything to complain after a quick test.

Thanks for testing. That's a testament to Aeromatic++. It's not intended to produce a finished product and probing beyond a quick test is likely to reveal limitations. But if it produces a flyable model with the fairly limited information put into it, I think that's a good result.

[sanhozay]

I've just committed 0.26.4, which has a few bug fixes to my Aeromatic++ FDM and engine related matters.

For the time being, that's my FDM. Take it for what it is which is a vanilla Aeromatic++ FDM tuned for performance in a normal flight envelope. I will revisit it at some point, probably using JavaFoil to get better lift and drag numbers for the wing and flaps. There is some numeric instability in there still but I'm going to fly it and see how it performs.

Next stop is more work on the electrical system, in particular the circuit breaker panel. Then there's the nose cowl for the 150/160, more cockpit work, etc, etc.

[sanhozay]

A couple of new commits:

0.27.0: Electrical panel and updated electrical system. Improved internal lighting. Pretty much all switches work now.
0.28.0: Pitot icing reduces pitot pressure and eventually blocks the tube.

[IAHM-COL]

@All
The Pup is merged to FGMEMBERS now
https://github.com/FGMEMBERS/Beagle-Pup

IH-COL

[bomber]

Richard, can you put some floats on the beagle ?