Can I fit SS7 wings to a Kitfox 5?

Sorry if this has been asked before!
I recently bought a KF 5, and I was wondering if there is a difference in the wings of a SS7 and the 5? Can I fit a set to the 5 fuselage? Is it even worth trying it?
Can it even be done?
What, in layman's terms (that I can understand by looking at my 5) is the difference between the SS and my 5 (2003 model).
Which differences will concern me at my home at 4000 ft in warm South Africa? Driven by a Franklin 4 cylinder 125hp @ 2800 Rpm.
I understand there are cosmetic differences - What are they?
Bear in mind that I am most interested in taking off short and landing short.
Cruise takes second place in my mission:- FUN!

The SS7 has the ability to convert for a Tail Wheel to a Nose Wheel built into the Fuselage. Also the Tail Rudder shape is a little larger and is squared off at the top. I do not believe there is any difference relative to the Wing, or Ailerons.

The model 4 through 7 wings are all the same size, shape, airfoil. There are some different strut lengths so different strut attach bracket locations. have someone measure the distance from root end of the spars to bolt hole for the strut rod end on a seven to compare to a model 5.

Rooster,

It is my understanding that the wings on the 5 through 7 & SS are identical, including the flaperons with the exception that the standard wing tips on the current SS uses a short wing tip rather than the hoerner style (like you have). So, to get S7 wings on your bird, all you have to do is use the ones you already have!.... how's that for frugal.:)

Regarding what a person can do to get their best short field performance, probably the best first action is to become totally familiar with the characteristics of your bird and practice short field technique with what you have - and practice with all flap settings - the best flap setting might be different for takeoff than for landing short. I diddled around for a couple years before I felt I had developed the skill to do an actual 900 foot runway......and it worked out fine with room to spare. The reason I mention pilot technique is; although I know Kitfox pilots are on the upper end of the short field performance curve....in practice I see an awful lot of planes of all types burning up 3/4 of our 2,800' runway just because the runway is there.

One thing you have going for you is the horsepower of your existing engine. Also, one of the most effective short field performance ingredients equipment wise is a low pitch climb prop......as long as you aren't so concerned with cruise speed. With the available HP, you should be able to suck the grass out by the roots on a short takeoff run if you have a prop optimised for takeoff/climb. A low pitch prop also helps with shortening the landing roll if you throttle back to less than no-thrust RPM on short final....the prop disk pretty much acts like a big flat piece of plywood and adds a lot of drag. There are a number of threads on this list regarding KF flyers who spend time minimizing idle RPM to assist with short field performance - a good thing to search on.

One thing KFs seem to like is being flown as light as possible. While there is not a lot a person can do about the basic weight of the airplane, making sure the plane is not loaded with non essential baggage helps as well as not carrying the full 26 gallons of fuel in the wingtanks if you can do that with the mission. I suppose, tongue in cheek, a person could consider going on a diet; but, that is sort of like breeding elephants....takes two years to get results:mad:

FWIW - I run a Warp Drive prop with a cruise setting in front of a 100 HP Rotax......And I have been careful not to have the idle RPM set higher than it needs to be. That gets me in and out of any airport I have encountered, even those slightly less than 1,000 feet with room to spare....However, I would never have attempted that with just a few hours of KF experience.....lots of practice gets you very close to the advertised short field performance but we do need the practice first. Another minor point which I have found that helps.....not running low pressure in the tires....a higher pressure reduces tthe takeoff roll a minor amount due to reduced rolling resistance. Tire pressure is one of those things we have widly varied opinions about depending on the tires and the landing places we pick. I keep my tires at 25 PSI and then try not to score too high on the richter scale with my landings.

Sincerely,

Dave S
KF7 Trigear
912ULS Warp Drive
St Paul, MN

Hi,
As far as I know, the fuselage and wings on a 1550 lb gross model 5 are the same as the 6 and 7.
The 6 and 7 have improvements /aditions to the 5 design.
The 7SS is a lighter where possible 7.

The model 7's have a larger elevator than the model 5.
This helps with pitch authority at slow speeds and I think would be a plus for short field ops.

Vortex Generators might help somewhat.

An inflight variable pitch prop helps allot .

What is your empty weight with the Franklin ?

What is your STOL goal in terms of length and obstacles?

Hello All.
Thanks so much for the replies!
Dave S - You have taught me a lot, thanks. I was realising these things and you confirmed it and drew my attention to pertinent issues. With two up, I am still getting it wrong on the flair, as I used to hang the C170 there on the prop with a touch of power and grease a 3-pointer for a 300 foot landing with two up, but I have found that the "touch of power" on a Kitfox gets me ahead of the drag curve again and I end up plonking it down untidily. I am battling to get her close enough to the ground and to the stall to for the neat 3-pointer. Like you say- PRACTICE!
I am still too afraid to use 2 notches of flap with two up and no baggage, as all those I have spoken to so far have told me that I am likely to not be able to get the tail down and may stick the prop in. I am managing to peg the blue line on approach, as I have slowed the idle down to 750 RPM. I have a Warp Drive at 13 degrees. (she arrived with it). I have been reading the builder's books and he did try 12 degrees and got 2550 RPM static, but he wasn't prepared to cruise slowly. I might try that for a blistering take-off, but I have already got 800fpm climb from my 4000ft asl field on a 25 deg Celsius day. KMach- Thanks. I have a 881 pound empty weight 5. I am going to try and get her on a diet by taking out one of the two fuel pumps, look at doing a new exhaust and changing the carb heat shroud to a little one like the Robinson helicopters have. Then I can move the battery forward and put a smaller one in etc. There are a couple of other things that I can work on as time and money become available.
My goals are to handle a 350-400 foot ground roll for landing and take-off and I will try to land in our local Lucerne (alfalfa) pastures for tea and a chewing of the fat with my brothers and other friends.
The bottom line is; Thanks so much guys! I really value the input and I am having fun trying it all out.
I will be practicing a lot. SAFELY!
Regards
Reid

Where does your center of gravity (cg) fall?

There should be enough elevator authority to handle full flaps on landing without nosing over. You may need to move some weight around to get that more to the rear.

Here is the w&B.

I want to go up and practice at a constant altitude and really feel her before I bring it back towards the ground.
When we went to fetch her and fly her the 500 miles home, we felt as though the tail was going to drop out at short finals, but I suspect that we were just too unfamiliar with the type. (both myself and my test pilot pal had not flown one before.).

This was at loaded baggage and two adults with a good load of fuel (70litres).

On my SS7 I readjusted the horizontal trim ballscrew to give more nose-up range (less nose-down). The readjustment used essentially to the bottom of the slot in the tail covers. This gave me enough nose up trim for full flap landings, but still requires some back stick elevator pressure. There is plenty of elevator authority for this. I can't say if its the same on a model 5, but suspect it is.