Flaps or not

Hey all,

This question is mainly addresses to someone like Jerry Burr - but I'm open for all input!

Just what performance advantage do you get from having (standard) flaps on the Super Cub wing?

The flap design itself is simple (just about one step removed from the split flap design). Thus its' aerodynamic performance might be considered more in the direction of drag production rather than lift production?? (I'm pretty sure that 1st notch produces more lift than drag - but what about 2 nd and 3rd?)

The flap system adds weight. NOt much, I know, but we are always carping about ounces and pounds adding up and detracting from performance.

For the AVERAGE SC owner - NOT the hard core working guys flying in the bush - does the incorporation of flaps produce any noticable performance improvement? I.E. shorter takeoff or landing? (In a different thread it came out that for the AVERAGE SC owner the installation of VG's WITHOUT extended gear and/or big tires to increase the 3 point angle of attack was a waste of time effort and money as the AVERAGE owner couldn't fly in such a way to reap a benefit.?!

What do you all think?? Let me hear from you!!

John Scott

John,

Flaps are good.... wouldn't even consider a Cub without them.

I'm currently working on a 'wide' Cub with new Dakota wings. Planning to lengthen my flaps (and make them and ailerons thicker, ala Husky) and allow them to extend to 50 degrees down and maybe 5 degrees up. This (high drag) will allow more power during low and mid-speed approaches, quickly decelerating the aircraft in the flare when the power is pulled to idle. Cubs without flaps are real floaters.... and that really works against you if you use extra speed during your approach because of turbulence or strong crosswinds.

If you are building experimental, suggest you use three hinges on both flaps and ailerons... and use spades on the ailerons too.

The takeoff advantages of flaps speak for themselves.... especially on floats as the aircraft needs less nose up pitch to lift off.

That's my .02 worth.... I'm sure you'll get more good advice.

I'm a very low-time, very (very!) average pilot flying a 150, obviously with flaps. There's also an L21 based at my field, 90HP (or so), no flaps, which I fly in a fair amount. The L21 is a very capable machine, but there's no question flaps make a big difference, both on take-off and landing. There's a short strip here, sloping very uphill, where the approach has to be made over a hill opposite. Without flaps you literally have to skim the top of the opposite hill, then slip down the slope, which is OK, but it's definitely a lot easier with flaps. In this case, there's much less margin without flaps.

You can manage without flaps well enough, but given the option, why would you want to? Also, if you have a 150 (and certainly a 180) you'd want flaps much more than in a lighter aircraft because of the increased weight and its effect on the stall speed. It would be wrong to fly a 90 without flaps, decide it's OK and on that basis choose to go without flaps on a heavier aircraft.

In terms of performance, the flaps will give you far, far more than you'd lose from the weight penalty of installing them.

Choose flaps.

David

Flaps

If you're flying a little J-3 or PA-11, I'd keep it stock just for the simplicity of the plane and the resale of being "original". You only have to fly a PA-18 for a few minutes doing landings and take offs, with and without the use of flaps to get your answer. Flaps on these heavier planes is a must have item. Crash

To Flap or not to Flap...

Crash got it right on the money.

The 3 and the 11 would be absolutely ruined by adding flaps--you just don't need them. Besides, it is a good deal of fun to come in for a landing with the controls completely crossed and watch the eyes on any bystanders get real big. Those birds just don't need them--and they are very capable of getting in and out of tight places.

A 150, on the other hand, has a different power/weight/lift ratio and greatly benefits from any help it gets from the flaps. Not all "little" airplanes are alike--a J-3 will outperform a C-150 in many areas (except cruise, of course). Both are wonderful airplanes but have different capabilities and applications.

The difference in performance really would be noticeable, even to the "average" supercub owner. It isn't quite like with VGs because, as you say, you have to be working close to "the edge" to see the difference with VGs; not so with flaps. I once owned a 18-105 special without flaps and now a 18-150 with flaps. While it's true you can slip a cub in pretty short, I couldn't get in as short as I can now, with flaps. Getting out short depends a lot on power, of course, but there is no mistaking the difference in taking off without flaps vs. with them. As the above posts indicate, if simply flying a cub is what you're after, a J-3 or 11 might be the answer at less cost. If you're even thinking about "performance" as your question indicates, I think you would regret building a cub without flaps.

I just finished rebuilding my PA-12 and in the beginning I chose to fly it without flaps for two reasons.
1) My only previous flying experience (500 hrs in a Aeronca Chief) was in an airplane with no flaps and I felt more proficient not having to think about when and how to use them as I was learning to fly a new plane with all the controls in a different place etc.
2) After deciding to put them in and going through all the time and expense I wanted to truly judge the performance difference.

So, I flew the 12 without using my flaps for the first 10 hrs. Now let me tell you, I had trouble controlling the airplane at slow approach speeds and had to have a much higher angle of attack and lower visability over the nose on final. I thought that my lack of proficiency(not flying in a year and a half) was the cause of my control problems. I can't tell you how much of a difference it makes to have them! I had instant stability below 65 MPH. Some people will say that they have a stock 12 or whatever and that they perform just fine without flaps but all I can think of is that they would be highly impressed if they had them. Take off distance was reduced by at by at least 1/4. The ability for a steeper approach also really helps out in a lot of the places I go. As a matter of fact, I can't think of an ocasion when this wouldn't be advantagous.

flaps or not

on a 90 hp pa18 with no electrics would you guys recommend flaps or not or would vgs be enough

I fly a 90hp SC without flaps. It is great but I have wondered the same thing. Is it worth the extra weight and expence?

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