Rules Of Thumb- Please add to these

[tempdoug]

1. 1% downslope = 10% more runway
2. 2% upslope = 8 mph tailwind
3. 10 knot headwind reduces stopping distance by 150'
4. 10 knot tailwind increases stopping distance by 500'
5. 10% speed increase = 21% landing distance increase.
6. 50' extra altitude at threshold adds 1000' to landing distance.
7. "Duck unders" from 50' adds 4 to 8 kts. and up to 400' additional rate of descent.
8. Total length of strip means little; obstructions can halve the total usable distance.
9. Each 1000' of density altitude increases ground roll 25%.
10. A 700 fpm climb at sea level becomes 140 fpm at 11000'. At 80mph, in level terrain, that puts you 315 agl at 3 miles.
11. An eighth inch of frost increases takoff distance 50%.
12. To determine ruway lengh: 70 mph x seconds x 1.5 (70 x 12 x 1.5 = 1260'; use 2-way average in wind).
13. At 80 mph and 1000fpm, you need 710 horizontal feet for every 100 feet of obstruction. (to clear a 50' obstacle by 50', an additional 1000' of runway is needed)

[aktango58]

When taking someone with you, their idea of 'light' requires one size larger aircraft than intended


Every bounce extends landing distance 50'

[SJ]

One I always like is from Sparky Imeson: If you have not reached 70% of your rotation speed by the runway half-way point, abort. This is handy if you don't have DA calculations, etc, and are in the high country.

sj

[Iflylower]

The sum of reciprocal runway headings always equal each other.

(Ie. 09 is 0+9=9 and 27 is 2+7 is 9. Or 12 and 30 is 1+2=3 and 3+0 =3.)

[Jhilgard]

11 and 29?

[MN_flyer1]

For Recipricols: <18: +20-2, >18: +2-20 For some reason I just can't add and subtract 18 very easy in my head. I.E: 17 --> (17+20-2) = 35, 26--> (26+2-20) = 8

Tim

[Iflylower]

2+9=11

less scientist, and more rule of thumb. It works.

if I told you the list of rules and exceptions, you wouldn't use it



Im adding this cause I couldn't articulate the rules in my first post...the best and easiest.

The sum of the numbers equal the reciprocal, or the sum of the reciprocal.

Ie 5 and 23. 2+3 equals 5
Ie 13 and 31. 1+3 equals 3+1
ie 10 and 28. 2+8 equals 10

So I see a 04 northeast runway. I know the recip is southwest 2 something...2+2 equals 4, so 22.

Probably clear as mud, but I use it.

[Iflylower]

Tim, I also use the +2 / -2 for reciprocals. Works great for working courses on airways to/from. But, you can cheat and look at the tail of the HSI or bottom of the vor head. This is a dying art with more and more following the magenta line.

The trick is add a 2 to the first number, subtract a 2 from the second number. But, if it doesn't work, subtract a 2 from the first and add a 2 to the second.
examples:
143 reciprocal / add 2 to the 1 and subtract 2 from the 4 = 323

or 345 reciprocal / subtract 2 from the 3 and add 2 to the 4 = 165

or 076 reciprocal / add 2 to the 0 and subtract 2 from the 7 = 256

Fast math. Always check to make sure it's right. A couple like 190/010 get sticky, but still work, just more carrying the numbers in add/subtract. But 010/190 are so close to 180/360.....

[Iflylower]

This isn't really cubbing more instrument flying...But i do use it flying. I learned 1% of your a/s or more accurately your ground speed to lead a 90 deg turn, say intercepting a dme arc. At 180 kts start your 90 deg turn at 1.8 nm. 250 kts lead 2.5nm. And 100 knots 1nm.

[HydroCub]

One I always like is from Sparky Imeson: If you have not reached 70% of your rotation speed by the runway half-way point, abort. This is handy if you don't have DA calculations, etc, and are in the high country.

sj

Don't forget to add "70% AND ACCELERATING" to that statement..... You can reach "terminal runway" velocity on hard surface (contaminated) just like the "terminal water step velocity" on a float plane...... also applies to tailwind takeoff. If terminal ground velocity is 70 mph and liftoff is 55 mph, you're screwed when the tailwind gets gets close to 15 mph...!!!!

[HydroCub]

Any rules of thumb for the dreaded DOWNWIND TURN...???


Sorry..... year is almost over, I couldn't resist..!!!

[HydroCub]

Tim, I also use the +2 / -2 for reciprocals. Works great for working courses on airways to/from. But, you can cheat and look at the tail of the HSI or bottom of the vor head. This is a dying art with more and more following the magenta line.

The trick is add a 2 to the first number, subtract a 2 from the second number. But, if it doesn't work, subtract a 2 from the first and add a 2 to the second.
examples:
143 reciprocal / add 2 to the 1 and subtract 2 from the 4 = 323

or 345 reciprocal / subtract 2 from the 3 and add 2 to the 4 = 165

or 076 reciprocal / add 2 to the 0 and subtract 2 from the 7 = 256

Fast math. Always check to make sure it's right. A couple like 190/010 get sticky, but still work, just more carrying the numbers in add/subtract. But 010/190 are so close to 180/360.....

Add 200 and subtract 20.... or subtract 200 and add 20 works well for my simple mind...!!

[Scooter7779h]

Take offs are optional, landings are mandatory.

Always make round trips.

Always park plane like it is ready to leave, you don't know when you will have to in a hurry.

Planes are replaceable, human life isn't.

If you have made two attempts to land, go somewhere else or come back another time.

If you don't feel 100% confident about landing or takeoff operation, before your fully committed call it off

[cubdriver2]

Take offs are optional, landings are mandatory.

Always make round trips.

Always park plane like it is ready to leave, you don't know when you will have to in a hurry.

Planes are replaceable, human life isn't.

If you have made two attempts to land, go somewhere else or come back another time.

If you don't feel 100% confident about landing or takeoff operation, before your fully committed call it off

I don't like the last one. Feeling 100% confident sometimes makes you stupid. I like 90% so that I stay awake.

Glenn

[JP]

Landing upslope you will think you are going way too fast. You aren't.

Taking off upslope you'll think you aren't climbing. You are.

"Smooth as Silk" has different meanings in different cultures

Gray light in the snow and flat water are nasty illusions. Fly next to something to really gauge your height.

The quieter they get, the sicker they are getting.

Figure out where the dry counties are before you launch on a long X-C in a Cub.

Pushing generally has much better results than pulling.

Practice with your GPS, etc. in the cockpit on the ground. For some reason they are harder to operate in flight.

Airspeed = floating. Every mph will take you a bit further than you thought you might go--this is both a good thing and a bad thing.

When it quits, it quits--even with the magical VGs. Try not to do this any higher than 3 feet or so.....

You really do burn more fuel when heavy and operating at high RPMs.

"Floatplane" turns in a Cub are a useful trick. Try them at altitude first, though.

Do not fly directly over the turkeys to get them off the runway. They go straight up when they fly.

Really wet grass and close temp/dewpoint on a summer morning is a great recipie for carb ice.

It all goes to the back when you drop it.

Don't drink diet pepsi without a gel bag on board when you have a great tailwind that you are loathe to leave.

The Power Curve is a really good thing to know about, early and often.

It's polite to let someone else try out the "watch this" moment before you do.

When someone says you hit a tree with your wingtip, pay attention.

Never, ever ski fly without another airplane along.

On the snow in a 90 hp Cub power is your friend--keep the power in.

Put the water balloons in a plastic kitchen sized garbage container instead of a plastic bag. They are easier to manage.

Never go to the lake without a sports air horn onboard.

Carb heat on when skimming the base of scuddy clouds.

You really can't beat a Gentex visor.

If you aren't wearing it when you put her in, you probably won't have it for the night in the woods.....

[Patrol Guy]

a couple of mine -
1. Don't fly in anything that weighs less then me.
2. Don't sleep with anyone who weighs more then me.

[Alex Clark]

1. When you let your EGO do the flying, it will always carry you right to the scene of the crash .................................................. ..............................................
2. 70 miles per hour equals 100 feet per second. So a 10 second gravel bar is 1,000 feet long and a 20 second lake is 2,000 feet long. .........................................
3. A float-Cub that needs 1,000 ft to get off glassy water will need another 1,000 feet to get over tall trees............................................. .................................
4. Stowing 50 pounds of gear in a float compartment will be like an extra 150 pounds during a low speed bank and turn. WHY CAN'T I GET MY CURSER TO SCROLL DOWN ???? PLUS I CAN'T USE COLORS....

[bearsnack]

Don't try to turn around in low weather to late, if you can no longer see a turn around spot you have gone to far and you just might be done.
And my favorite saying for bush flying....." The wind is your friend"

[Scouter]

When ski flying, you can go from the most fantastic flying day of your life, to the absolute worst day of your flying life, in the blink of an eye
Jim

[Aviator13]

ALWAYS leave yourself an "out"!
ALWAYS think engine failure and where you are going.
Go arounds are free.
You can NOT recon too much.

[aktango58]

Scud running: as you slow down to apply flaps due to vis, use the flaps to reduce your turn radius on a 180

[HydroCub]

Missed approach / go-around procedure in virtually every airplane you will ever fly:

PU - PU - CU

aka Pitch Up & Power Up.... then Clean Up (often a multi-step process)

[Alex Clark]

WIND SPEED GUESS-TA-MATION FROM BODIES OF WATER
1 knot or less= Glassy surface
1-3 knots= Light ripples on some surface areas with glassy water on lee shore.
4-7 knots= small wavelets that do not break and have round smooth tops.
8-12 knots= Wave crest begin to break, foam lines (streaks) run in direction of wind.
13-18 knots= White caps appear
19 to 24 knots = all white caps, heavy foam streaks, dark areas of rolling mechanical turbulence that look like shadows on the water surface

[cubdriver2]

When ski flying, you can go from the most fantastic flying day of your life, to the absolute worst day of your flying life, in the blink of an eye
Jim

I warned you about flying with Tim.

Glenn

[Alex Clark]

When in doubt,,,,, chicken out!

[flydakota]

My Buddy Chris Z. Tells me the only time you have to much gas is if you are on FIRE!
caution, Cubs have ruined a lot of good men! I for one know this is true! Cuz it's all ya want to do!

[Iflylower]

"If Airnav has fuel listed pretty cheap, you can't have it."

its:
broken
unattended
locked up
private
or empty

[S2D]

Every bounce extends landing distance 50'

Unless there is a "lot" of vertical involved !!

[aktango58]

Unless there is a "lot" of vertical involved !!

sorry, 'Bump' adds 50, bounce 150

[S2D]

I don't know, some of my bounces end at the bottom of the first arc !!!

[Ole Bob]

Some years ago when I went for my MEL checkride the examiner, after quizing me on the airplane, said something to the effect that "I just wrote a book on flying rules of thumb. Would you like to buy a copy?"
Yeah. pretty obvious!!. But it was well worth my getting my blood pressure up.
The book is "FLIGHT PLANNING SIMPLIFIED" An absolutely great book. Written by Jim Porter. If you can find a copy I recommend it. A wonderful compilation of the "easy" way to analyze a huge variety of situations.
And, yep, I passed the check ride!

[ag-pilot]

Any rules of thumb for the dreaded DOWNWIND TURN...???


Sorry..... year is almost over, I couldn't resist..!!!

Screw it,,,just do it!!!!!

[Pat]

I'm not much of a numbers guy.........WIT: Whatever It Takes..........And.....FLY THE DAMN AIRPLANE!

[scubber]

When trying to get it on/off the ground and things are going to heck in a hand basket, do what ever it takes to keep it straight. And, usually all else works itself out. My father always told us kids, "if your going to spread it out . .spread it out in a straight line". Seems the concentration on keeping it straight and not trying to think of several other "oh sh_ _", has saved my butt, and the cub, more than once. Larry C.

[jgerard]

"Remember that it's only the theory of flight and that we are ruled by the laws of physics"

"pitch for airspeed - power for altitude"

"slow down to go down"

(meaning DON'T dive at the runway, pull the nose up, get the plane dirty, bleed off energy, and control the decent with power)




Jason

[OLDCROWE]

My instructor always tossed in "Slow down before you come down". I never really paid attention to what he meant in the cub where cruise to a 500 FPM decent was still in the green with the same throttle setting...Not so in the 180!

[aktango58]

My instructor always tossed in "Slow down before you come down". I never really paid attention to what he meant in the cub where cruise to a 500 FPM decent was still in the green with the same throttle setting...Not so in the 180!

Now go fly a Bonanza (with a competent Bonanza Pilot) and try tipping the nose down a wee bit.

Or just move the seat forward one notch while in cruise and keep your hands off...

[OLDCROWE]

Now go fly a Bonanza (with a competent Bonanza Pilot) and try tipping the nose down a wee bit.

Or just move the seat forward one notch while in cruise and keep your hands off...

No Thanks!

[N636P]

There are three useless things for a pilot:

1. The air space in your fuel tank.
2. The air space above you.
3. The runway behind you.

Glenn