Beagle Pup Flight Testing

[KL-666]

Hi Richard,

I tried to take off with it again. The pitch instability is a lot better now. But no matter what prop effects are set, the plane wants to go left still. Strangely at one try it did not for a few minutes, but then it started again.

Another more serious issue is that at a few hundred feet climbing below 500 ft/min, the speed just completely goes away. Most stunningly is the rate of the speed drop. As if "At 200 ft, remove speed" is programmed in it. (Or it could be the slowdown of the strong slip i had to fly in, trying to stay somewhat straight)

Ow, and the auto start is broken. Takes more testing time now.

@Bomber
I do not believe in controlled environment testing like you do with spawning in the air and glide. I am more a real life tester, see if it flies plausible and do tests from there. This way many situations can catch my attention, instead of just one. For now i noticed the plane is unflyable (speed to 0 and turning left not long after take off).

What are we actually trying to prove here? Whether vspaero can generate a flyable fdm? If that is the case, we are done. My answer is no.

Edit:
Just did one last test. There are a few things i noticed about pitch.
- Level flying, the strong turning left tendency disappears/normalizes.
- Pitch slightly up or down and the left tendency reappears very strongly.
- The slightest pitch change exponentially multiplies itself, and strong counter inputs are necessary.

I think the FAA will rate this plane a death trap

Kind regards, Vincent

[bomber]

@ Vincent, it's not a belief system, it's an exercise in observation that we're doing here..

The fact that you're touching the controls means you influence the outcome, so your observations are naturally different to others.

Try spawning the plane at 10kft 50kts, touch nothing and just observe and I'm pretty sure your conclusions will not change.... and I'm sure if a couple more people observer the same thing we can conclude it's a fact.

Your observation that the plane turns to the left is clouded by the big spinny thing at the front of the plane... is the turning to the left being caused by that or is it the aerodynamics ? ... The prop will cause this effect and it could be correct however the aerodynamics could be so far off that the 'package' is incorrect... or it could be that the aerodynamics are correct and the engine is so torqued up, that it's at fault.

I'm not saying your testing method is incorrect, just that there's a time and a place for this type of testing... basically once the plane in safe to get in and take off.. which as you've observed it isn't.... And also getting bang for bucks whilst testing is important, or to put it another way, we only have so much free time so ensuring that the feedback is targetted to give the maximum amount of help to the flight modeller is in my opinion optimal.

I was accused recently of not listening to people who'd tested my glider... this wasn't true as I was thanks to these observations nudging the flight modelling technique hopefully in the right direction, sometimes not, but all roads lead to Rome as they say.
It's too early to judge the vspaero method, all that can be said is that it's not produced a plausible flight model at present, but that could be down to Richards interpretation of the table as much as vspaero.

@ Richard, this plane is still longitudinally unstable, considerably more so than before.... I'd suggest you turn off all other moments and just concentrate on understanding the ins and outs of getting this plane longitudinally stable, such that it has the correct damping.

regards

Simon

p.s. No offence meant to anyone.