STOL kit for 140A

[8474]

Anyone know of a STOL kit for the A model?

[6863]

Yes. It's called a 120 with a C-90 engine.

[8424]

Blaine,

STC SA995SW was issued to Bob or Barbara Williams, of Udall, KS, in the 1970's. It was for a STOL kit for the C140A. I sent a letter to multiple addresses listed for the Williams' about 3 weeks ago and two were returned as Undeliverable, and Unable to Forward. The STC was listed in the FAA list of STCs for the C140A, TC 5A2, at that time. I just looked for it again, and the STC has been removed from the list. Evidently someone associated with the Williams has had the STC canceled. You can confirm this by looking here:

http://rgl.faa.gov/Regulatory_and_Guida ... &Query=5A2

I also contacted an owner a of C140A with a STOL kit installed (found pictures and N numbers in Google Images searches/addresses in FAA Aircraft Registry) and he had the Williams STC and confirmed that the Williams STC was the only one. Do a Google Images search for N9667A and N9654A.

So, it appears we are out of luck in the STOL world.

I've read mixed opinions of the effect of VGs on the C20/140.

I really wanted to install the STOL kit on my 140A, and am now considering the VGs.

Hope this helps.

Steve

[8474]

Hi Steve,

thanks very much for all the research you did, that is really too bad that the STC was cancelled. I have seen a Canadian registered 140A with the drooped leading edge installed but have no idea which STC was used for that. I'm going to do a bit more digging to see if I can find out. It may have been done many years ago with the now cancelled STC.

Since the "A" wing is so similar to the early 150 wing I would think that the kit that is available for the very early 150's would work, but with the 140A not listed it would not be eligible.

I have considered the VG's as well but as you say they seem to have some mixed reviews.

Thanks again for your reply.

[6183]

Why do you desire STOL performance? Short field you're based on, short field areas you want to fly into, etc.?

What are the current specs on your aircraft, i.e. engine, propeller, current weight of aircraft, etc.?

STOL performance isn't just installing VG's and special wing tips, and then volla you've got helicopter performance. What are the basics you're trying to accomplish?

[8424]

Mike, I'm not sure your question is for me or Blaine, but I'll answer anyway!

My residency is in the interior of Alaska, located 14 miles up the Takotna River from McGrath, but I've been in Oklahoma for a while taking care of in-laws. My first C140 was a 1948 model with the C90. It was a really fun plane and flew it both in Alaska and Oklahoma. I flew it in and out of some pretty short strips, but was never comfortable enough to use any of the great sand bars. I never put it on skis...just didn't have good enough performance for off airport use.

The guy with a cabin close to ours in AK has an 700 ft strip that I would really like to keep the plane I have now at, but I won't do it without a STOL kit. It is a 1950 140A and I'm doing the O-200 STC plus repairs. It's heavy and painted. I have removed 35 lbs of radios/ADF, but don't want to take on the job of stripping/polishing (it's urethane paint!). I did that to a C150 and once is enough. The 140A was full IFR capable, so all the gyros are gone with both 8 inch venturies/tubing, etc. There are still A few lbs. to be found and discarded. I can't put a climb/seaplane prop on it with the STC. That certainly would help, but I couldn't get anywhere very fast! I put a seaplane prop on my 150 HP Stinson 108 while flying out of T of C, NM (5,000 MSL), to help out with density alt, etc. It would jump of the ground and climb pretty good, but 85 mph was top speed!

My strip here in Oklahoma is one way in-one way out, with about 1,000 ft on the south end for landing and 1,000 ft on the north end for take-off. (50 ft rise in the south 800 ft, another 30 ft rise in the middle of the north 1,000 ft). 50 ft trees both ends and power lines on the south end. I flew the C90 140 out of here comfortably, but not a lot of margin for safety. The STOL capability would increase that margin.

So, now you know why I would like a STOL kit!

Steve

[6183]

Thanks for that information Steve, it gives a better indication of why you're wanting to meet STOL requirements.

If I operated on a 700' airfield I would certainly opt for some improvements also. You're correct in removal of all unnecessary weight from the airframe. My own 140A weighed in at 955 lbs. from the factory when new; however that was with the basic flight and engine instruments of the day, and no paint except trim. In addition, it had the C-90, but has since been converted to the 0-200. I utilized the airplane almost exclusively for power line patrol here in NW Florida, and on the hottest days of over 95 degrees F. didn't attempt routine patrol work unless it was a dire emergency from the power company.

Looking at the 140A owner's handbook with the C-90 and standard McCauley propeller for the aircraft at gross weight, and the sectional chart where McGarth is located, the airfield you're describing may be at an elevation between 350 - 900 feet MSL. I did some interpolation, and found that for example, at a 500' elevation airport at 40 degrees F (current temp at the McGrath, Alaska airport when I checked), your ground roll will be 483 feet; however, to clear a 50' obstacle will require an area of 1605 feet. You would need a clear space ahead of the 700' runway of 905' to clear a 50' obstacle. That distance increases to 555' ground roll at 80 degrees F plus the distance required to clear a 50' obstacle head. This is assuming correct pilot technique and an engine that is developing rated takeoff horsepower with a standard propeller for that engine. Landing roll at the same elevation and temp requires 448' assuming you touchdown at the edge of the runway. Obstacle clearance as you adds to that figure. You might not have much room to spare if elevation is higher and temps climb.

My good friend Randy Thompson who owns the 0-200 STC I believe has had an additional propeller approved; however, I don't know it would be considered a climb prop. Normally the 0-200 STC allows a 6950 propeller which I believe is considered the standard propeller although I've heard of others with a 6948 climb prop installed. I just don't know if the STC allows it.

You might want to consider an 0-235 or 0-290 upgrade assuming that you could get the STC approval to do so. I'm sorry I don't have any performance data for those engines; however, you would see a advantage in takeoff and climb that may suit your needs. Just my opinion.

Mike