I have seen BV and others do some impressive pattern flights with the KC......only thing it lacks is a real clean entry and exit to upright (+G) spins and flicks due to the wing planform......same deal with the BobCat and Bandit using a similar wing planform, but outside (-G) spins and flicks are clean.....


Tom

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Actually, Tom, the difference between upright and inverted spinning is not a function of wing planform it is wing SECTION AND INCIDENCE. The Bobcat wing and presumably the Kingcat since you align the two, has a thick symetrical root section tapering to a semi-symetrical tip which is washed out. At the stall the root stalls first, as it should, and makes the spin entry uncertain and the spin itself, oscillatory. Inverted, we now have a wing which has an adversely semi-symetrical section (flatter on top) and washed IN. Thus at the stall the tip stalls first, making the spin entry cleaner and the spin more stable.

That section change is what causes the wing rocking on the Bobcat as it gets near the stall, an excellent visual indication of the approach to the stall in a model as we have no tactile warnings of the stall or an ASI to refer to!

Thats exactly how my Bobcats behave and I have done great number of spins with them , both upright and inverted.

I suspect that if these models had symetrical section wings they would stall and spin in similar fashion uright and inverted but we would lose the benign handling at the approach to the upright stall.

Regards, David Gladwin.

David:

Guess I used the wrong word...planform.....what you describe is what I was referring to.....the shape of the airfoil, changing from root to tip......

The fellow that designed the airfoil for BV posted here on RCU recently and described his design in some detail.......

It really has worked great on all the BVM planes that have used it.....

Tom

What is the weight difference in the two models? Also, has the boom issue with the KC been addressed if you were to buy one new now?

Thanks,

DK

DK, the boom reinforcements came installed on the Kingcat I bought a few weeks ago.

Sean

Did you get the Merlin installed on the KingCat?

yup

Well.. actually.. The reason the negative snaps and spins are better is more simple than this. In upright flight, both the vertical and horizontal stabs get blanked out a bit by the wing planform at high angles of attack. In inverted spins and snaps, the tail is in clean air.

Except that a Bandit exhibits the same behavior concerning inside/outside snaps/spins. The BobCat/KingCat has exactly the same planform and airfoils as a Bandit.

AMEN

Doug,

How's the little girl?

I know for a fact that Robert Sickels built a remarkable B58 Hustler with scale operational landing gear. A few of these kit were sold.
Sorry I cannot upload some of the images of his kit. Think someone else took up the task of making them into a kit (possibly JHH )

Cheers
David