stol kit for 170b?

[marr]

I am a new owner of a 54 Cessna 170b, and I would like to put a sportsman stol kit on. I would like to know if there are better stol’s available for a 170b? Leave any comment I would like to hear good opinions.

Sincerely,
170 member

[Bruce Fenstermacher]

I would consider Vortex Generators. I have them and like them. They are easy to install and remove if you would want to and I believe they will cost less that any stall kit. I haven't flown a plane with a sportsman stall kit to compare but I believe you get the same performance.

There are several topics discussing the pros and cons of both stall kits and VGs. Search for "Sportsman STHOL kit" and "Vortex Generators"

After reading those topics if you haven't already, I'd be glad to rehash this subject again.

[N170BP]

My '54 has the Sportsman kit (was on there when I bought it).
Are you sure you want to spend $2K+ and add 18 pounds of
weight to your 170?

The nice thing about the Sportsman kit is it actually
adds wing area.

The bad thing about the Sportsman kit is it actually
adds wing area (lightly loaded with gusty winds will
make for "fun" landings....).

Like Bruce says, we've tossed this subject around on this
list a number of times. On the one hand, I think Cessna
had the wing right from the get-go. On the other hand,
Cessna did change the wing (on the C-180 and C-185)
in 1973 I think, to something very much like the Sportsman
leading edge cuff, so there may be some merit to it depending
upon how you intend to use the airplane. Which leads to the
question: What will be the mission parameters for your 170?
(i.e., how & where will you most often operate it?).

[t7275tr]

I have a Horton STOL kit on a 54 170B. Having compared my 170 to several other B's, a 52,53 and 55 without a STOL kit, I can say that there is a definite difference in short field performance and stall speeds. I like to visit every landing field that I see when out cruising and there are several 1000 ft long ultralite fields that I freqent and feel very comfortable going in and out with 2 people and full fuel. If you have no need for improved short field performance, you can save the 2,000 plus pricetag for a STOL installation. Myself, I really enjoy the increased performance, and would pay the price if I didn't have the kit. VG's in addition to the Horton kit would be an interesting combination. Anyone with experience with this combination, please post a response.

Tom Race
1946C
sn 26091

[Bruce Fenstermacher]

I don't buy the argument that "Cessna would have done it or would do it if it was any good". Bela almost said it here and its been said on another topic going right now about flap seals.

First off. When this wing was designed there was a lot of things that hadn't been done yet in the area of flight and lift. Do you think Cessna really developed a wing in early 1950 that couldn't be improved? Remember where we were then. early in the jet age. 747s where a pipe dream. How many people in 1950 thought man would walk on the moon in less than 20 years. that technology hadn't been developed either.

Cessna doesn't do it now because of liability. To admit that their product could be improved would ruin them.

As for the VGs. There is no weight penalty. They cost less to buy and install. The process is easily reversed. They don't effect top end except that they will always increase the effectiveness or your ailerons. They work. You will never fly your aircraft as slow on approach or departure as they allow.

As for them falling off, I've completely lost one in 4 years. I've knocked a few off refueling and a recent hale storm took off 3. They where all easily glued back on in a few minutes. My plane has never been unairworthy because of missing VGs.

[N170BP]

Bruce, that's kinda why I mentioned the "hook" wing update on
the 180/185 in 1973. Of course, nothing was perfect in
the mid 1950's, and everything can be improved upon
(and no doubt, has been improved upon, and will yet be
further improved upon).

I think the key here is to honestly evaluate/consider
how the airplane will be used, and in doing so, determine
whether the mission profile warrants the investment of a
Sportsman kit, or any STOl kit for that matter, or VGs, etc.

Having flown a bone-stock '53 for a short while (about 50 hours),
and having put 330+ hours on my '54 in the last year & a half,
I can definately vouch for the fact that the Sportsman kit can
make for an airplane that is quite capable of impressively slow
flight/approach speeds (and a better handling one at slow speeds).

How often to I truly make 100% use of that slow speed/flight/
approach capability? The honest answer is "very rarely". But it is
nice to know the capability is there....

Additionally, I'm not necessarily on the STOL kit side of the fence
argument-wise (vs VGs). I have access to an early 180 with VGs
and it is equally impressive in-so-far as slow flight capabilities /
qualities are concerned.

[ak2711c]

I installed one on my 170B. It definetely lowered the stall speed. The angle of attack at stall is much steeper. In level flight it cruises just slightly more nose down because of the extra lift. Between the extra lift and the aileron gap seals that it comes with I noticed about a 1-2 mph increase in cruise speed. I go into a lot of short off airport strips and it does help. When I am dragging it in real slow to land short the tail wheel will normally touch first, and I have 26" Gar Aero mains. If you are really good you can install one in 40-45 hours of labor, that is with out paint. I would recomend telling the factory to keep there cherry lock rivits and credit you for them, then just bite the bullet and go buy the good cherry max rivits. They are spendy but well worth it for the time and frustration that is saved, as well as a better looking finish product. This is a permanent mod so make sure it is what you want. Once it is done your wallet is forever lighter and your plane is forever heavier!

Good luck!
Shawn

[marr]

Thanks for answering my questions i hope to some day put the STOl kit along with the vortex generators. My cessna has the back seat out and is pretty much a two man plane i feel this could really make a difference. the reason for wanting the mods is because of my dad's cessna 180, this plane without mods is a great performer but also has the STOl and VG's and it really helped out.


MARR

[funseventy]

The only problem is that it is still low on HP! Yesterday was the first time that I had flown in the temps above 85 this season and it was a little puny. The stol kits help us reduce the stall speed but as mentioned it takes a lot of angle of attack to take advantage of them. While trying to take off you will be AOA limited, especially with stock gear and 600 tires. If you aren't going to do something to increase the AOA you could be hurting your TO performance by adding the 18 lbs. If you are looking for the first step in STOL performance the cheepest thing is to put on 8.50's. I notice a greater percentage increase from that than anything else you could do. The stol kits do help you get in better, but I haven't seen this to be the short coming of the 170. I have seen plenty of landings shorter than 300' (one at 160') with a stock wing.

If you use the same technique as I, you will see a change of about 200' with the bigger tires.

20 degree flaps, raise the tail as soon as possible and then keep it as low as possible for the entire take off run and it will get off short and consistent. If you use other techniques you will get of a little shorter but if you gauge your speed a little wrong you will take longer. I personally like the consistency.

Plus you could always repitch you prop like Bela (?) and I (7649 - 120 mph @ 2500 RPM & 7.2 gph) or buy the seaplane prop for even better performance off the ground but lousy cruise speed.

[N170BP]

My prop is a 7651, but at 2500rpm (my tach checks within
10 rpm of a hand-held strobe), it'll only do 116mph with 8:50s
on it. How are you getting an extra 4mph with a 49 pitch
prop?

[funseventy]

Bela,

I might be turning a strong 2500 RPM, I like to always see it on the plus side so I might be running as much as 2550.

I always planned on 118 mph until the paint job and now I see 121, but I plan on 120 and I am pretty close. This also checks out with the GPS averages.

I will be going to Oshkosh; do you want to do a flight of two?

Kelly

[N170BP]

That makes sense. I actually set 2500rpm but with
parallax (however that's spelled, looking at the gauge
from the left seat at an angle) it's probably more like
2475rpm or so.

I'd like to do Oshkosh but I burned most of my
vacation this year down in Florida.

[zero.one.victor]

I considered 850's,but went with 800's cuz they're lighter & less draggy,plus they're approved by TCDS. For where I go, I think the 800's are a better choice for a 170 than the 850's.
Instead of bigger main tires, a couple friends of mine modified their 120/140's for more three-point AOA by shortening the tailspring. They actually cut the main spring off flush with the second leaf,then drilled thru both to re-mount the tailwheel. I don't know that I go along with that part of the deal,I think the leaf springs flexing would tend to try to shear the tailwheel mounting bolt, but otherwise it might be worth considering. Maybe use a shortened (L-19?) main spring but leave out the second leaf so you don't have to bolt thru two leafs?

Eric

[funseventy]

Eric,

You are not in need of the 8.50's because you have 180 gear. I think that is a fact that should not be eliminated since the 180 gear is 2" taller than the 170's stock gear. Now in my opinion the 8.50's or even 26" goodyears on stock gear would be lighter than 8.00's and 180 gear. If you put the bolt through two springs you make sure one of them is an elongated hole. This is the stock set up for the Pawnee Springs on a Super Cub.

Kelly

[Bruce Fenstermacher]

As for the bolt going through 2 springs this is the way most Pipers are that I've looked at. Granted Pipers may not be as heavy on the tail as our Cessna 170s. Since I bought my 170 it has had 2 main springs, instead of the one main and second shorter spring, with the tail wheel bolt going through both. I have inspected this bolt on a regular bases looking for damage and there has been none to this point. The second spring hole is not overly elongated but does have some. I'm not suggesting anyone do this as you would think the bolt would get sheared. Not so on mine, your milage may vary.