Tom,
Thanks for the links. Having now read both, I can see that, from the NTSB perspective, this was pilot error. And you are right, descending 800 feet at a 50 or 60 degree angle at 80-90 knots only takes about 9 seconds, (figuring the vertical component to be 60 mph). I figure that changing from Beta to forward thrust would have been in the last 200 vertical feet, which only gives 2 seconds to obtain forward thrust and flare.
If it is pilot error, as the NTSB asserts, check out that Wayne Handley had 25,000 hours, and 200 plus in this airplane, and that didn't save his landing. Yes, as an aside, he had the pressure of the crowd, and the extra enthusiasm that comes from that (not good) but he was used to that.
It is imperitive, to my way of thinking, to read about this accident and look at how that could be waiting to trap a turboprop Super Cub.
First, we land our Cubs as short as we can, over obstacles. Idle thrust, full slips at full flaps, at stall plus one knot, with a touch of power to round out at the bottom. A short dive at the bottom to get the necessary airspeed to flare is safer, but still we use power to flare sometimes. Or even drag it in, working way out on the backside, hanging on the prop. This is routine stuff to muster the best performance out of our Cubs. It is not a stretch to suggest that we would not learn to use beta, to descend even steeper, and if our timing is not spot on, incur a similar event as described in this accident report. The report states that the turbine and prop were pulling hard at the time of impact. That power was just called for a second too late, which could have been affected by gusts or other variables as well.
The Super Cub is such a fine machine to learn to fly well, and safely, in the full range of its performance. I hope that the turboprop can be incorporated, with all it additional capabilities, just as safely. A Cubs inherent stability, high lift wing, powerful tail and slow flying capabilities which give us long times to react will make this kind of accident less likely than on the aerobatic plane. But such a Cub, flown in this manner, will become dependent on the engine and prop both operating, and being operated perfectly, every time. So much for landings.
Takeoffs with 255 hp at 35 mph will have a deck angle of over 60 degrees as well - and may even be vertical in gusts. The time required for pitchdown in the event of engine failure, or to break a stall, will be even longer that that of a light cub climbing at 35 mph under an 8241 prop. Fuel systems will have to be be designed to carry fuel the 3 vertical feet up to the engine.
Ernie, how did the Porter get fuel to the engine, and how much time did your crack pilots take to master flying it the way you have described in your writings? Were there accidents with the Porter related to max performance takeoffs and landings?
Bob Breeden
Certainly it has to be with CS prop (to eliminate your worries, which are true). My comment; you will have to place the engine almost two times further ahead, and the inertial forces acting on the engine mounts will be too much, compared with the reciprocating engine (too many high rev. parts like turbine, gear train and all that). So be carefull with the engine seperation danger.
He used these procedures as practice so when he came up with a 2000 foot runway with a soft spot right in the middle, he would be ready for it.
