High altitude t/o with stock 170

[robw56]

Thanks rob,
That is what I was looking for. I wish I had the 10degree flap setting but that is another thread. I have been using flaps at high altitude because I just don't like the feeling of extended takeoff rolls at high speeds. I'd rather get airborne quicker and accel in ground effect and climb. I go to bishop and south lake a lot and some of my more exiting takeoffs are when the gusty winds start to play with me towards the end of the takeoff roll. Lots of ground speed but the plane is still not ready to lift off.
I have never had time to do testing at high altitude airports because I am always going somewhere and don't want to waste the time.
Anyway thanks for the report. I know what the manual says but it is nice to get an actual report.

Have fun this weekend, I have to work. Delta will be mowed this weekend.

Since you don't have the 10 degree notch and you will have plenty of runway I say just do a no flap takeoff. I know what your saying about the extended takeoff roll though, it does feel funny. I think in the long run you will have more altitude at the end of the runway this way though. Too bad you have to work, you need to come up to Trukee with us next time! Looks like its going to be a fun weekend. I might have to check out the delta when I get home.

[Watkinsnv]

Buzz,
I have been out of RNO and I'm out of Stead ( Reno Air Race) I had my 170 there when it was stock kind of. Now its got a LYC O-360. Anyway I use 1 notch of flaps everywhere on every take off just like I land with full flaps on every landing and retract them in ground effect as air speed increases. You'll get off quicker, sooner, faster. Let me know when your up here and what your up to. on that other site. You ####### !

[Bruce Fenstermacher]

Having owned a B model with the ten degree flap range and I used it all the time. If I ever own another and it does not have that range, I would add it. It wouldn't be a super high priority but something I would do when I found the part and got around to installing it. Had I never had the 10 degree setting I wouldn't know the slight difference it makes and what I was missing.

I preferred taking off with 10 degrees selected over 20 degrees because I felt there was added benefit of a more positive rate of climb flap but less drag than 20 degrees. In a few none scientific tests I concluded I could not get of the ground much faster with 20 degrees selected than the 10 degree and I would want to leave out flap sooner in the climb out. I could and would leave the 10 degrees in for a longer time in the climb out and then of course I had less flaps to leave out and trim the aircraft.

At Boulder City when I flew Doug"s B model a while back the lack of the 10 degree position was one of the minor things that threw me off. When applying flaps I was use to 4 positions and jumping to 20 degrees would through my mind off. Then departing with 20 degrees of course I had to take time to slowly leave out 20 degrees. Again this is a very minor point but just one of many environmental and equipment changes I was experiencing flying out there.

[GAHorn]

My airplane came with 20 degrees...but least year I installed the ten degree sector. While I can't
provide any definitive data....i have to admit that there are times I feel ten is more appropriate than
twenty...particularly on unpaved or rough strips.

[Bruce Fenstermacher]

My airplane came with 20 degrees...but least year I installed the ten degree sector. While I can't
provide any definitive data....i have to admit that there are times I feel ten is more appropriate than
twenty...particularly on unpaved or rough strips.

At our field at 500ft asl they want us to climb as quick as possible for noise abatement. I used 10 degrees off the pavement to improve the lift with less drag and I'd leave it in until I was about 500 ft agl. Anytime I wanted a little extra boost either high altitude (which I really never was) or hot but wasn't trying to just clear a 50 ft obstacle I used is 10 degrees.

[Jr.CubBuilder]

Wondering what the wisdom is for a stock 170 takeoff at high density altitudes. I know the book says the distance is longer with 1 notch of flaps. I tend to disagree at least for my 5-6k strips around CA. I tend to get the airplane into ground effect and slowly retract the flaps. It seems to get me airborne the quickest. Thoughts?
I'll be heading over to Reno next week and it going to be hot and I'll be near gross. I'm going to do some testing.

My experience with the stock motor, and now with a modified motor is that the plane will get airborn faster with flaps deployed at 10 or 20 degrees. I use this a lot on bumpy strips from sea level up to 5000' MSL to get the plane off the rattling/jarring/bumpy junk as fast as possible. I like using twenty degrees of flaps and usually milk them off gently after I have a few feet under the plane. I have the ten degree notch which I find nice sometimes and use it a lot for loitering/sightseeing. The fastest way I can get the plane off the ground is to set the flaps at 20 and keep the tail down while the plane flies itself off. Be careful if you are loaded, I suspect you can make the wing fly a bit sooner than the tail will want to at the back of the loading envelope.

I think for clearing a 50' obstacle flying with the C145/O300 the numbers in the book are right on, but the caveat is that the book assumes you are at nearly gross weight and they specify the climb speed. Note however if you look at the book again they indicate the best climb speed below the takeoff numbers and the best climb speed drops below what they specify for the takeoff numbers above. I use the book as a reference, and it sets my limits for the plane, but I would put money on a lighter plane or a better pilot being able to beat the published numbers in the book with a stock motor. The numbers in there are a nice safe conservative indication of what the plane will do. I think there are situations when it is best to fly the numbers in the book, and there are also situations when it would be better to get the plane airborn sooner to get off the rough ground, or angled over in a crab, etc. Getting off the ground quick however does not set you up for a sustainable rate of climb without changing things immediately after the wheels leave the ground.

[blueldr]

George,
Be Honest with us. Did you change the flap lever sector for the later model or did you (like almost everyone else) bootleg
another notch in the sector?

[GAHorn]

I had a NOS ten degree sector....and my original was slightly worn at its 20-degree notch.
I installed the NOS unit.
Anyone who needs a serviceable 20-degree unit....only has to tell me.

[buzzlatka]

George

I'm on a iPhone and searching is painful. Where or how do I get. The ten degree selector?

[GAHorn]

George

I'm on a iPhone and searching is painful. Where or how do I get. The ten degree selector?

It's a standard Cessna part. www.cessnaparts.com

[blueldr]

buzzalatka.
The quickest way to get that 10 degree notch is with a Nicholson file.

[bagarre]

How much work is it to swap out the flap selector?

[bagarre]

Sorry, missed that.
I hate when people have to repeat themselves on my account.

[GAHorn]

I'd advise against the Nicholson file method....as it takes too long. It's much faster to use a hack-saw and then do the finish work with a file.
(Of course, I'm only guessing since I used the genuine NOS part.)

[170C]

Fourth notch of flaps-----------George, there goes that orginality