whee wrote:Good responses, thanks. I didn't figure anyone would go to full power during run up to set the mixture, good way to ding a prop.

You're actually not at full power during static runup, as you won't be at full RPM as when moving. But for roughing in the mixture, it works fine.

For my Cessnas down Lower 48, I use first knuckle on my right index finger for 5,000 ft DA. Sometimes fudged a tad further out, or a skosh further in, but always the first knuckle.

Gump

lesuther wrote:That is my impression of the Bo as well, except the 182's climb gradient seems considerably better than the Bo. I've followed one out of Cabin Creek earlier this summer and was smoked getting to Cold Meadows, but I was able to out climb the immediate terrain way better.

He was just not flying it to its capabilities. Most retractable gear pilots will takeoff and level off at about 10 feet while they retract the gear and accelerate. This is the wrong procedure to clear an obstacle. You need to stay dirty, flaps and gear down and in the Bo climb at approx 80 MPH indicated for the dirty best rate(Best rate clean is 110). The faster you go the less the rate of climb.

For my Cessnas down Lower 48, I use first knuckle on my right index finger for 5,000 ft DA. Sometimes fudged a tad further out, or a skosh further in, but always the first knuckle.

Soooo..., Gump,
Does that work for us "knuckle draggers", too?

lc

Question, because I'm completely dumb about Bonanzas. But why leave the gear down? Seems like pure drag. Flaps hangin' and 80 I understand, but not the wheels.

Gump

Littlecub wrote:Soooo..., Gump,
Does that work for us "knuckle draggers", too?

lc

Ya know... I've worked all of the above ways to set the mixture. But in the end, when I look down and see where the red knob is, it's always first knuckle out of the panel. Give or take a tad or skosh if its warmer or cooler out.

Gump

Without an EGT or analyzer, it works pretty well to use run-up rpm, whatever that is, and lean until there's a slight loss of rpm (works with both fixed pitch and CS props), then enrichen a couple of turns or a quarter inch. If you do the same thing at full throttle, it comes out about the same without as much risk to the prop as full throttle does.

Of course, with an EGT or analyzer, you can do a little fine-tuning, but the results are about the same.

As for leaning aggressively for taxiing, there is no way that the engine will be damaged--it's developing very little power. And the best way to make sure you haven't forgotten to enrichen before take-off is to have leaned so aggressively that the engine stumbles if you try to add much more than taxi power.

For myself, leaning on the take-off roll isn't very workable on a short and narrow strip--I'm more concerned about maintaining control and getting off safely. I much prefer to do the leaning during the run-up, and leave the leaning on the take-off roll to those who have Sparky Imeson's skills--that was one of his recommendations in his Mountain Flying Bible.

Cary

A good cause/project for RAF or BCP would be a concrete run up pad at JC and Moose Creek and a couple of other main/less than hard core strips......
I know, it isn't necessary, but they are nice..... Real nice, in fact.
Particularly if your trying to sort out a mag problem.

Just a thought....
lc

Littlecub wrote:A good cause/project for RAF or BCP would be a concrete run up pad at JC and Moose Creek and a couple of other main/less than hard core strips......
I know, it isn't necessary, but they are nice..... Real nice, in fact.
Particularly if your trying to sort out a mag problem.

Just a thought....
lc

Grass seems like it's fine for high rpm, static runup. It's just the dirt and gravel surfaces that present the problems for props. I feel like pouring concrete in these places is just...wrong?

Treefeller wrote:

Littlecub wrote:A good cause/project for RAF or BCP would be a concrete run up pad at JC and Moose Creek and a couple of other main/less than hard core strips......
I know, it isn't necessary, but they are nice..... Real nice, in fact.
Particularly if your trying to sort out a mag problem.

Just a thought....
lc

Grass seems like it's fine for high rpm, static runup. It's just the dirt and gravel surfaces that present the problems for props. I feel like pouring concrete in these places is just...wrong?

Especially if you are in a tail dragger - that much extra clearance under the prop. Should be alright on grass to 1700RPM (not gravel......)

Les, the pilot, did a good job flying it into the trees as best he could when he got there. Yes, leaning is critically important at high density altitude before takeoff. I lean Lycoming engines at any altitude. They want lots of fuel to start and then want to run lean at idle and full power. He may have leaned before the film started. It is important, in the mountains, to consider which way is downhill and how we might get there in ground effect, if possible. Taking off toward lower ground is always an important consideration regardless of the wind. Gravity thrust is powerful. Yes, he probably should have aborted on the runway. Getting into low ground effect earlier and staying in low ground effect longer would have given him extra free kinetic energy of pressure airspeed. He would have accelerated much faster. Had he stayed in low ground effect, he could have made a rudder turn (using aileron only to keep the wing level) to the big meadow to the right. This would have been an excellent forced landing area or he could have continued the rudder turn, in ground effect, to lower terrain. Anyway, he stuck the nose between a couple of trees and didn't kill anybody.

If you are at a strip high enough to pull less than 65% power you can do anything with the red knob you want. Back when the old Breckenridge, Co airstrip was open (9,450, gravel) and I based and flew out of there I saw how good and bad many different aircraft would perform. We had 13 aircraft based there and our own above ground fuel farm in the early seventies. We had a V-tail Bo based there and in the summer he would use almost all of our 4,000+ feet and that was downhill with 2 people. Also had a Mooney and it was worse than the Bo. Two people and it was a struggle to get off, he finally moved it to the Front Range. Had a brand new Bo fly in with 4 young people for a concert one time and they decided to take off uphill into a small headwind. We always took of downhill unless the wind was strong out of the south. The guy yanked the Bo off and it struggled in ground affect for several hundred feet before sinking into the dredge rocks. All four survived with life threating injuries. Most of the planes were 182's with a few 180's including mine till I got the 185, a 170 and a 180 horse Cherokee and one 172. The lower hp planes did ok when lightly loaded. The Cessna high wings did a good job. We had a number of accidents there, mostly loss of control or running off the end of the runway. The one I hated to see was a guy and his wife from Chicago. They had just purchased the Champion Sparkplug Company 180, a 1954 if I remember correctly and bought new by the company. It was the nicest 180 I had ever seen at that time. They were headed to Aspen on a sking trip and he wanted to show her Breckenridge. On landing he lost it and got a wingtip into the 10 foot snowbank and cart wheeled it up the runway, they were ok.
Ron

Interesting comment Gump. On my 108 I lean to the first index knuckle as well, from there just a trim as you indicate.

When excess engine thrust for climb runs out, we probably shouldn't be there. But somehow we are. We now have to look for extra energy. What is left. Wind: are we taking off into the wind as much as possible? Do we know which way to turn to find the best orographic lift? Do we always fly slow in updrafts and fast through downdrafts? Gravity: can we take off down hill? Which way is lower terrain after takeoff? Are we prepared to use gravity thrust (descend) after clearing obstructions? Are we prepared to give up altitude in any turn (let the nose fall through naturally) since we know excess engine thrust to replace the lost lift is not there? Ground effect. Do we always get the nose gear off or tail up (tail dragger) as soon as possible? Do we always get the mains off as soon as possible? Do we always stay in low (six inches to three feet, depending on roughness of surface) ground effect. Do we know how to get to lower terrain in ground effect if possible. Do we understand how to use the kinetic energy of pressure airspeed to zoom climb over limited height obstructions and then to level over the obstruction to regain pressure airspeed?

When excess engine thrust for climb runs out, we probably should have learned to fly the wing, just in case.

Years ago I had heard the retractable Cessnas with all the gear doors would create more drag while the gear was in transit so if the trees were right at the end of the runway leave the gear down, made sense at the time. What if the trees were on top of a little ridge a mile away? Nobody seemed to know where the break even point between leaving the gear down or retracting it was.
My wildassedguess is that if airplane A uses less distance than airplane B to clear a 50' obstacle at sea level it will at 9000' as well. The performance degradation is likely a percentage, thin air affects everybody by the same %. Obviously some of the techniques mentioned will make a difference, my wag assumes the same leaning, wind, slope etc. are being used across the board. Turbocharging is your friend. Even jets lose power as you go up.

But God is bigger.

Nosedragger wrote:You can't beat a high wide wing on a hot day in the mountains, lots of shade for the folding chair and you can stand up easy on your way to the cooler while you wait for better air.

Best advice out there.

There is nothing different about high DA air, or basic physics at high DA. All that really matters is excess hp and weight. It's still all about f=ma, or ft=mv. That being said, takeoff speed is a biggie....you have to accelerate to a higher speed with less HP. For two airplanes of the same weight and hp, the one that takes off at 65 mph will need nearly 70% more takeoff distance than the one taking off at 50 mph, and its climb gradient will be much worse.

The Pacer is around 300 lbs lighter at gross than a 170, which means it gets off the ground faster, but I recall getting left behind during a climb with a 170. I think the 170 probably has a better l/d (i didnt get called a simonized manhole cover by the tower for nothing), and that meant it likely has a few extra excess hp than the Pacer in flight.

I recall both planes flew about the same on a hot muggy day in the backcountry, and that is why the cooler/chair option always worked for me.