Beagle Pup experiment

[bomber]

Thanks.....

Now this plane works on my machine but with FG being real fussy please give us the heads up if you have trouble.

Oh and please do get to a safe hight before spinning this plane.... push the stick forward straight away to ensure the spin doesn't flatten... if it does it takes longer to get out of it... opposite rudder and if in a flat spin full aileron....
Neutral as soon as you get out of it or there's a good chance you'll just end up spinning in the opposite direction.

[IAHM-COL]

Not wanting to derail this topic, but if you want to put yourself in a spin go test fly the beagle pup for me...

I'll schedule some puppy test next week. All I know abou this is making a fly from gate to gate, but you have more specific instructions which I am not sure I know what they are. Can you clarify what is the "tests" wanted, again?

[bomber]

This is the first of a series of flight models I'll release...

Beagle pup
Cessna 172
Ask 13
DRI
Spitfire.

Specific tests..... well knowing it works on your machines would be a start... then it's over to the orcas to run take off , stall , performance testing.... and finally to have fun using the flight model to trial spin, which I guarantee you'll have never experienced the like before.

Simon....

[Richard]

To start off the flight testing of Simon's Beagle Pup.

Flying with Fair Weather: METAR XXXX 012345Z 15003KT 12SM SCT041 FEW200 20/08 Q1015 NOSIG
Gross Weight: 1598lb ; Fuel 87 87 4.68
CG 36.3in
EGOD RWY 20R.

Test1. Taxiing and takeoff.

Start off with 25% throttle. Accelerate up to 15 kts. At this point elevator deflection will generate enough pitching moment to pitch to +15degrees (when the tail contacts).

Braking performance is good with the spring and damping seeming to be OK (but I don't know).

At 50 kts I could rotate, generate enough lift to climb a small amount and then a loss of control resulting in pitch / yaw moments and an upside down craft. The amount of pitch moment generated from the elevator makes it hard to determine the cause - however I would expect to rotate into a stall at this airspeed. The next test I rotated at 60 kts being careful to only apply a few degrees of elevator and achieved a successful takeoff.

Once in the air I found that the rate of climb was possibly a little low, but at 1589 lbs that's quite heavy so it is plausible (again I don't have any figures or pilot reference manuals to cross check against). However in the air the pitch moment is far to precise.

Overall all of the control surface movements in air seem to be far to effective and instantaneous. Possibly lacking damping (e.g. the affect of the rotation rate Q on CM); or this could be the moments of inertia. At this point all I can saw is that the control surface inputs are too directly coupled to the result. It warrants further investigation.

If I pitch up into a high alpha position the resulting yaw and roll is quite extreme - again this could be due to the aforementioned problems.

That's just for now; I'll try to get time tomorrow to post more test results.

[KL-666]

I'm getting a little lost here. So there is a Richard and a Bomber version? Please add links to the exact craft that should be flown.

Kind regards, Vincent

[IAHM-COL]

https://github.com/FGMEMBERS/Beagle-Pup => Richard Senior's Original Version (GPL)
https://github.com/FGMEMBERS-NONGPL/Beagle-Pup => Bomber's version (CC FDM alone)

The Other Richard's version is not in FGMEMBERS because it is "All Rights Reserved" (FDM alone). A link was offered above in this thread

So in total. 3 FDMs to compare. All three FDMs used different methods to get at a JSBsim.

[bomber]

First off thanks Richard for confirming my flight model works on your machine.... that's a relief.

At 50 kts I could rotate, generate enough lift to climb a small amount and then a loss of control resulting in pitch / yaw moments and an upside down craft. The amount of pitch moment generated from the elevator makes it hard to determine the cause - however I would expect to rotate into a stall at this airspeed. The next test I rotated at 60 kts being careful to only apply a few degrees of elevator and achieved a successful takeoff.

To be honest this is exactly what I'd expect, as initially the plane is flying in ground effect but if you climb out of it whilst still below stall speed you'll stall.

https://www.av8n.com/how/htm/takeoff.html#sec-takeoff

Once in the air I found that the rate of climb was possibly a little low, but at 1589 lbs that's quite heavy so it is plausible (again I don't have any figures or pilot reference manuals to cross check against). However in the air the pitch moment is far to precise.

It's as underpowered plane

Overall all of the control surface movements in air seem to be far to effective and instantaneous. Possibly lacking damping (e.g. the affect of the rotation rate Q on CM); or this could be the moments of inertia. At this point all I can saw is that the control surface inputs are too directly coupled to the result. It warrants further investigation.

I'm kinda leaning to the control effectiveness being more down to the lack of pilot strength being taken into account within the control system than the actual ability of the plane to roll at the said rate... something I'll look at.

Thanks for the feedback.

Simon

[KL-666]

Tried the Bomber variant now. Here are some things that i found, based on general flying principles.

1) It flies. Slight torque left, which should be expected.

2) Controls are extremely sensitive. Slightest movement and it goes into a full roll or pitch.

3) No sense of inertia. End a roll or pitch and the movement stops abruptly.

4) Flaps need some tweaking. Flap 1 seems draggy. Could not make speed with it on after take off. Flap 3 is very lifty. Needed some 20 degrees nose down to descend at all, and full trim down could not surpass it at just above 60 kts.

5) Body drag seems good. Could slow down in desc.

6) Nice asymmetric stalling. Very benign recovery. Do nothing and recover.

Kind regards, Vincent

[IAHM-COL]

It sounds like Bomber's got something nice going on here

[bomber]

2) Controls are extremely sensitive. Slightest movement and it goes into a full roll or pitch.

Ok as we've now had two comments along similar lines can I ask are you both are you flying by
a)keyboard
b)mouse
c)joystck

Can I also ask, I fly with my flight model at 50hz (yes and no ground problems) does changing the hz have any noticable effect on control sensitivity for you guys ?

3) No sense of inertia. End a roll or pitch and the movement stops abruptly.

I wonder if this is tide into the pilot stick force issue I suspect is at fault... I'll have a look at this no sense of inertia

4) Flaps need some tweaking. Flap 1 seems draggy. Could not make speed with it on after take off. Flap 3 is very lifty. Needed some 20 degrees nose down to descend at all, and full trim down could not surpass it at just above 60 kts.

Not sure why you'd take off with flaps on such a small plane.
As for the 20 degs nose down..... this actually is the reason for flaps, to get the nose out the way so as you can see the runway on approach.. All the other stuff that came with using flaps, such as increased drag, and slight increase in lift is a bi-product of it...

6) Nice asymmetric stalling. Very benign recovery. Do nothing and recover.

I don't understand this comment.......

first off what's your idea of an asymmetric stall ?
Did you try using rudder and putting the plane in a spin at the stall ?