Which STOL kit is best for climb?

[riggerrob 643]

Which STOL kit improves climb rates the most on popular Cessna jump planes?

Small leading edge cuffs (i.e. Horton)?

Massive leading edge cuffs (i.e. Sportsman)?

Drooping ailerons (i.e. Robertson)?

Drooped wing tips?

Wing tip extensions?

Flap gap seals?

Vortex generators?

Others?

Combinations?

Jump pilots: how much difference in climb rates did you notice before and after retrofitting?

What about differences in low speed handling?

Were take off runs noticeably shorter?

[freeflyguy 0]

You forgot to add a Pt6.

Now that is a STOL kit

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bzzzz

[quade 4]

If you want to increase climb performance, nothing does it as well as additional horsepower.

quade -
The World's Most Boring Skydiver

[DYEVOUT 0]

I'm not a pilot, but I jumped a C182 with (very) drooped wing tips. Asked 3 or 4 pilots if they noticed a difference - none did.

----------------=8^)----------------------
"I think that was the wrong tennis court."

[Craig 0]

I had an idea, but 8000Lbs of thrust might be a bit much

[SkydiveMonkey 0]

Yup, JATO's would do as well

____________________
Say no to subliminal messages

[pilotdave 0]

I don't know... but I think most of those are really for improving low speed characteristics, not climb rate. I've never seen a 182 with VGs, but I've heard great things about them on other types. Leading edge cuffs (at least on other types... again, i don't know what's out there for 182s) can dramatically improve low speed/stall flight characteristics, but I bet they add drag.

Drooped wingtips are pretty common for shortening takeoffs, but I've never seen any evidence that they work.

I agree with everyone else. Horsepower is the only way to go.

Dave

[AndyMan 7]

I voted for Joe Chows wingtip extension. His widebody 182's climb faster then any normaly aspirated, non "super" 182 I've been on.

_Am

__

You put the fun in "funnel" - craichead.

[fudd 0]

This is the modyfied C-182 at Skydive Hoakz. Mini jets are only used for climb, and it takes you to 14000' in only 7 minutes

There are only 10 types of people in the world. Those who understand binary, and those who don't.

[riggerrob 643]

Yes folks,I know that huge engines are the quickest solution to improving climb rate, however, this string is about AERODYNAMIC refinements to improve climb rates.

quote:"

Quote

I don't know... but I think most of those are really for improving low speed characteristics, not climb rate." end quote
Yes, most STOL kits are designed to improve low speed handling and take off performance.
My question is which STOL kit improves climb the most?

Fore xample, Joe Chow raves about his wing tip extensions, but Joe also has larger bore pistons in his 182s. On the other hand, my boss considered wing tip extensions for his 182s, but stopped when he found out they descend slower.

My boss also said that Sportsman STOL kits make little difference in Cessna 182 climb rates.

On the other hand, he believes that the Sportsman STOL kit helps his Cessna 205 climb a bit better. This echoes Van Pray's opinion of Sportsman STOL. Van Pray waxes eloquent about how the Sportsman kit is the only kit that increases wing area and re-pitches the wing. Van Pray believes that Sportsman's flap gap seals provide the greatest improvement, so great that Van Pray believes that a Sportsman STOL kit can pay for itself in only one year of operation in the high desert (2500' MSL) of California City.

• Quote

[MrHixxx 0]

Our Cessnas have wingtip extentions for the weight/balance improvement. Otherwise, we could find ourselves out fo the performance envelope with heavier jumpers...

-Hixxx

death,as men call him, ends what they call men
-but beauty is more now than dying’s when

[quade 4]

Quote

Yes folks,I know that huge engines are the quickest solution to improving climb rate, however, this string is about AERODYNAMIC refinements to improve climb rates.

OK, this is gonna sound kinda weird, but the reason airplanes climb actually has a lot less to do with the aerodynamics than it does the power to weight ratio. Aircraft climb because of horsepower in excess of that required to maintain straight and level flight. Aircraft decend because of a deficit of horsepower required to maintain straight and level flight.
As a matter of fact, if you look up the definition of horsepower, it's the amount of power required to lift a certain amount of weight in a certain amount of time.
The only aerodynamic mods that make any sense at all are those that clean up the airflow in very simple ways without addings a lot of weight. Whatever aerodynamic efficiencies created by the "solution" must also overcome whatever weight penalty they introduce. Light weight gap seals -may- make a very slight difference. Heavy weight droop tip extensions -may- make sense as far as low speed performance is concerned, but make no sense whatsoever as far as climb rate is concerned.
Things that make the most sense and will give you a definite improvement are larger engines or turbo kits.
The only other way to improve climb performance would be to lose some weight in the aircraft.
Either that or you can take a GREEN felt tip pen and run it around the edge of your CDs . . . I hear that makes them sound MUCH better. Oh wait, that doesn't work either.

quade -
The World's Most Boring Skydiver

[riggerrob 643]

Quade, there are actually THREE formulas for estimating rate of climb.

As you suggested, "power loading" (aka. pounds per horsepower) is one formula.

The second is wing loading (aka. pounds per square foot of wing area).

And the third formula involves span loading (aka. pounds per foot of wing span).

To increase rate of climb, you need to increase horsepower or reduce drag, increase lift or reduce weight.

Increasing horsepower is easy, just bolt on a bigger engine, then spend an equivalent amount of money on the STC paperwork and spend more money on fuel for the rest of the life of that engine.
Drag reduction makes little difference on Cessnas because of the low airpseeds they climb at. About all you can do to reduce drag is close the roll-up door.

Increasing lift is the toughest part of the equation. Wing tip extensions help, but they require reinforcing the spars, etc.

Reducing weight is easy, just discard the seats and CD player. Other ways of reducing weight including limiting fuel loads to only enough for three or four loads, or limiting the number of jumpers on board.

[quade 4]

Quote

Quade, there are actually THREE formulas for estimating rate of climb.

Actually there's only one;
R/C = (ETHPx33000)/w
You can play around with the variables is different ways, but this is the -only- way an aircraft climbs.
Simply making the wings larger (your #2 and #3) carries weight and drag penalties.
Again, I return to quade's simplified formula for lift;
Lift=M
M = money
The more money you have the more lift you can have generated.
In this case, the most efficient way of doing that is by increasing the horsepower.

quade -
The World's Most Boring Skydiver

[freeflyguy 0]

Ok, Want a new idea to this discussion, pt 6 and jet engine aside.

http://www.260se.com/features.html

I think this mod will actually help. Reason being, since the nose is being lifted directly, by the canard, you don't have to use as much down force from the tail, to keep the nose up. Make sense? Results in a cleaner aircraft.

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bzzzz

[diverdriver 5]

Actually, a bigger engine might use LESS fuel over a smaller engine since you get to the same altitude quicker. I've experienced this in the Monterey Bay C-206. They modified it with an IO-550 300BHP continuous. I was getting up and down almost a full 6 minutes faster. Even though the fuel flow was higher than the smaller engine it didn't spend as much time producing the power. Hence, less fuel used or same fuel used to go higher. Was a real kick.

Also, making a Cessna more "aerodynamic" is like saying the shuttle is a real "glider". Give anything enough airspeed and it will produce lift. But the Cessna is so dirty as it is that really only more HP will make it go up faster. You have wing struts and wheels all hanging out in the breeze. Form drag will kill performace much more.

Chris Schindler
www.diverdriver.com
ATP/D-19012
FB #4125

[pilotdave 0]

The canard will probably do a lot more for climb angle than climb rate. STOL kits (engine aside) are for decreasing ground run, which has little to do with climb rate. They probably add a bit of drag at high angles of attack which would not be good for climb rate. I still like the JATO bottle idea.
Dave

[pilotdave 0]

My aircraft design textbook gives this equation for best rate of climb...

vertical velocity =
{(550)(brake horsepower)(propeller efficiency factor) - (drag)(velocity)} / W

Thats the power available minus the power required, divided by weight. Decreasing drag helps, but increasing brake horsepower helps more.

Dave

[quade 4]

My equation (actually Bill Kershner's) is the exact same equation (really! it is!);
Rate of climb (in feet per minute) = (excess thrust horsepower x 33000) / weight (in pounds)
The phrase "excess thrust horsepower" takes care of all of that messy prop efficiency & drag stuff. The 33000 is a per minute value to use instead of the 550 per second number you used.
See "The Advanced Pilot's Flight Manual" by William Kershner.
The book has basically every formula you could ever want to play with and is well explained. If you fly and you don't know who Kershner is, you ought to.

quade -
The World's Most Boring Skydiver

[riggerrob 643]

We know that Joe Chow raves about his wing tip extensions made by Wing X
www.wingxstol.com
, but has anyone tried any of the other wing tip extension kits?

Has anyone flown a Cessna with extended wingtips made by Flint?
http://www.flintaero.com/index_menu.html