And the speed change through the turns in a race is NOT that significant. Ground speed - yes, but not airspeed. That's why a lot of turns are a "diving " turn. Trade altitude for airspeed in the turn so you don't need to waste power getting the airspeed back after the turn. You don't want to loose enough airspeed in the turn (heavily G loaded) to stall the flight surfaces - or even get anywhere close.
snipped-for-privacy@snyder.on.ca fired this volley in news: snipped-for-privacy@4ax.com:
Clare, you didn't think that out. Diving into a turn will gain you the advantage of not losing airspeed, but what do you do in the next turn -- dive again?
How many turns do you execute before you meet the ground.
If you dive into a turn, you must climb on the straights. If you climb during straight-ahead flight, you're "wasting airspeed" gaining altitude. Ain't no other way it works.
It's a closed system -- you cannot maintain an "average" level flight without expending a certain amount of power over the whole course. It doesn't matter (on average) where you spend it if everything is perfect... of course, things aren't 'perfect' in turns; the airplane is "dirty" in turns, so you use less power regaining altitude in straight flight than you would maintaining in in a turn.
But you _still_ "waste airspeed" gaining altitude. You can't not.
LLoyd
Another way of looking at air racing - to go fast you need to reduce LIFT to the absolute minimum required to keep the plane at the desired altitude - so the LIFT REQUIRED is only the weight of the plane. The lift PRODUCED increases dramatically with airspeed. The only way to correct for the massively inreased lift at speed is to CHANGE the angle of attack of the lifting surface(wing)- and the way to do that is to raise and lower the elevator/horizontal stabilizer hanging out back at the end of the "lever" that is the fuselage. Changing and controlling that angle of attack takes significant force - produced by the lift of the "elevator" - which is controlled by changing the angle of attack of the elevator. The angle of attack of the elevator is "trimmed" by the trim tab to neutralize the control input required to produce straight and level flight - so only CONTROL input is required by the pilot. If he wants to lower the tail - he provides input to lower the tail. If he wants to raise the tail, he provides input to raise the tail - he does not raise the tail by reducing the input that is keeping the tail down - nor does he lower the tail by reducing the input keeping the tail up. He just says "tail up" or "tail down" and the plane follows his instructions.
And some planes have "flying tails" that constantly provide positive lift in level flight - while other planes have "reverse flying tails" that contantly provide down-force in level flight. Just look at the airfoil configuration of the rear stabilizer/elevator on, say, a Zenith 701 and compare it to, say, a cessna 172.
No. but the LIFT BALANCE sure does!!!!
I wonder what he'd think about a flying wing? Is it still "nose heavy" if it has no nose? Or tail??
Clare Snyder wrote this wierdosity....
Clare... (sigh...) When, exactly, did you encounter any situation in straight and level flight were one needed more lift than the weight of the plane (or less)?
Level flight _describes_ a situation where lift is equal to weight.
It doesn't matter what speed range you're considering... you don't "reduce lift" to fly level, you keep it constant.
The only part of what you said that made any sense at all was that you may have to reduce the angle of attack to keep the lift constant at higher speeds.
????
LLoyd
Nope, you climb to the next one - means you don't "need to hold the nose down" as much!!!
You do NOT want to loose too much speed when in highly loaded flight - like a turn. Rather have to climb slightly in the straights than be too close to the ground, too "heavy" and too slow in the corners.
Eaxactly
It takes power to fly - - - and a LOT of power to fly fast!!
Yes, but lift increases with airspeed - to a point - and if trimmed for level flight at X000 feet at , say 300 mph, if you do not change trim you will NOT be at X000 feet at 500MPH
Hey LLoyd - what part of "so the LIFT REQUIRED is only the weight of the plane. The lift PRODUCED increases dramatically with airspeed." didn't you catch? You increase speed, you increase lift - so as you speed up you need to - get this - REDUCE LIFT - to stay at the same level.
In the Formula One racing, Tom Cassutt, the legend goes, was obsessive about getting his racer around the pylons as fast as possible, if not faster...
He was getting near 250 MPH out of a Continental O-200 engine (100 HP in a Cessna 150 - at 80 knots!)
Back in the 1950's He did the math to compare routes. Close in and a tight turn for the shortest distance flown, or out farther with a lighter turn and higher airspeed. He seemed to favor the longer route at higher speed as the best course.
Before he finally quit racing (dementia setting in) he was muttering about completely eliminating cooling drag from his racer. At those speeds air going through the engine to cool it account for fully 1/3 of the total drag on the airplane. 33% decreases in drag don't come easy or cheap though!
Tom figured that the heat (punny) lasted 8 minutes, and the engine would run full power for 10 minutes before seizing.
And it only takes him 15 minutes to change engines.
...
Nitpick - there are servo tabs, too. They work like trim tabs, except they're not independently controlled by a trim wheel. They move with elevator movement, in the same direction a trim tab would move, and reduce stick forces.
That was pretty good. It didn't support "The elevator - and the trim tab - do a LOT of work on a race plane at 500mph" one bit, except for the unfortunate case when the tab comes off. If that happens, it does do a LOT of work.
snipped-for-privacy@snyder.on.ca wrote: ...
The 701 does not have a lifting tail. You're nuts. The 701 tail pushes down to hold the nose up, just like the 172 tail does.
I see on their website
And that's EXACTLY what happened on the plane in question (P51 Mustang bases Reno Racer)
No, you need to understand how an airfoil works - then LOOK at both the Cessna and the Zenith. The Cessna has the camber on the top - and the bottom is flat. The airfoil causes LIFT in the upward direction. The 701 has the camber on the bottom - and the top is flat - meaning the LIFT is in the DOWNWARD direction. Forget about angle of attack and just look at the AIRFOIL. The airfoil creates lift on the side that accellerates the air-flow - following Bernouli's principal.
It is plainer than the nose on your face when you know what you are looking for. But you are RIGHT - the 701 does NOT have a Lifting tail
- but the Cessna DOES.
...
Where did you see this 172 airfoil? Elevator, or stabilizer?
No way. It would be tail heavy, unstable, with computers driving it. An F-16.
Stab. I'll have to take a closer look next time I'm at the airport The camber is not much, compared to the fat stabilizer on the 701, but from what I remember it is opposite in format from the 701
Many planes have pretty well symetrical stabilizers.
I guess "lifting tail" isn't totally accurate - but a lot less of a downforce tail. Different hacks for different tracks - a faster plane gets more downwash from the wings thet forces the tail down much more at speed. A slow-flying plane like the 701 and Pegazair depends more on the reversed airfoil for the downforce. On a very fast plane like the p51 the stabilizer is almost like a knife blade or a plank - not much camber either way.
...
Yeah, well, perhaps Richard is knowledgeable about boats. :)
A little...
Sept 20, 2011. At 6:30 the lake was so smooth it was glassy.
At 7:00 things changed! The cold front moved through and the wind picked up from zero.zero to over 20 gusting 36(!).
I had met Jim and his family earlier, circling each other to speak. They bought Stephen's Catalina 27 and were hoping the front would bring some wind.
It did. Ob boy did it did! Wind went from nothing to half a gale in nothing flat.
Good Times crew hadn't been out in this much wind in this boat before. They had a bit of trouble getting the main down downwind. But it finally did come down ok. I was just trying to keep from running over them!
At least it wasn't a totally boring afternoon! Some spray in the face, a couple of cold shots of adrenalin, and all was right with the world again.
Not a lot of video here, my phone kept dropping clips. (I learned that it does that if I don't close them properly) But sometimes I'm just too busy to worry with buttons! This was definitely one of those occasions. I'm impressed that I got what I got. From a telephone? Really!
Hey, I've got no problems with it at all - that is, with a little advance warning about what's going to happen. And "Informed Consent" comes into play too.
"Okay people, we're shaving 20 minutes off our approach. Face forward, heads up and well back in your seat, and here we go..."
You don't DO that with a full commercial passenger aircraft without giving the passengers a heads-up. Or at least an apology if you did it inadvertently, "No, that wasn't your imagination."
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Commercial flights into Saigon in the early 1960's used what I think is a modified single engine jet approach. Cross the runway at right angles to the final approach line and do a 270 degree, descending, approach.
The idea was NOT to fly over miles of perhaps uncontrolled terrain at low altitudes.
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