Steve Pierce
BENEFACTOR
Graham, TX
Does anyone know anything about the Kenmore gross weight increase on a Cessna 180 and them having 4 fuel tanks. I gotta bone up on 180s. 
Kenmore STC to up Gross Weight on Cessna 180
- Thread starter Steve Pierce
- Start date
mvivion
SPONSOR
Bozeman,MT
Steve,
I believe that the GW increase requires the big dorsal fin. When it first came out, it also required the O-520KAH engine conversion, but I think they have since gotten it done with the stock engine. Pretty sure you'll have to install a big dorsal fin if not already there. When I looked into this, it only went back to ~H models, but not sure on that. Mine was an H and it was eligible. The very early ones weren't.
MTV
I believe that the GW increase requires the big dorsal fin. When it first came out, it also required the O-520KAH engine conversion, but I think they have since gotten it done with the stock engine. Pretty sure you'll have to install a big dorsal fin if not already there. When I looked into this, it only went back to ~H models, but not sure on that. Mine was an H and it was eligible. The very early ones weren't.
MTV
Bill Rusk
BENEFACTOR
Sandpoint, Idaho
Steve
To the best of my limited knowledge there are 2 GW increase options. ART X-wing extensions and the Kenmore kit. The Kenmore kit is only applicable to the 1964 H and subsequent models. The kit is a very simple doubler in the tail section. (I have heard rumor that you may be able to apply it to earlier models but it would involve replacing the vertical stab and rudder. Not sure of this.) It ups the GW to 3190.
The X-wing is applicable to all models but only ups the GW to 2950.
I am sure others far more knowledgeable will pitch in. Mike V, Crash, StewartB...
Bill
To the best of my limited knowledge there are 2 GW increase options. ART X-wing extensions and the Kenmore kit. The Kenmore kit is only applicable to the 1964 H and subsequent models. The kit is a very simple doubler in the tail section. (I have heard rumor that you may be able to apply it to earlier models but it would involve replacing the vertical stab and rudder. Not sure of this.) It ups the GW to 3190.
The X-wing is applicable to all models but only ups the GW to 2950.
I am sure others far more knowledgeable will pitch in. Mike V, Crash, StewartB...
Bill
Skywagon
MEMBER
Prosper, TX
Steve,
I think Mike is correct...requires the big dorsal and is or was not available on the early models(not sure what year was the cutoff or why) Not sure about the 4 fuel tanks, unless someone was referring to the Flint Extended Tip Tanks for 185's...which would be 4 tanks and would up the gross weight to 3600 lbs.
Chris
I think Mike is correct...requires the big dorsal and is or was not available on the early models(not sure what year was the cutoff or why) Not sure about the 4 fuel tanks, unless someone was referring to the Flint Extended Tip Tanks for 185's...which would be 4 tanks and would up the gross weight to 3600 lbs.
Chris
mvivion
SPONSOR
Bozeman,MT
I think Stewart may have hit it on the head regarding the four tanks question. The H models forward had three side windows and essentially share the 185 airframe in most ways.
The original Flint tanks are internal tanks in the 180 and do not provide a GW increase. Flint now has an STC for the airplane that extends the wings and adds tip tanks. I believe that STC increases the GW as well.
Wing X is similar, with no fuel tank added. It too increases the GW, and I don't believe the big fin is required for that GW increase.
MTV
The original Flint tanks are internal tanks in the 180 and do not provide a GW increase. Flint now has an STC for the airplane that extends the wings and adds tip tanks. I believe that STC increases the GW as well.
Wing X is similar, with no fuel tank added. It too increases the GW, and I don't believe the big fin is required for that GW increase.
MTV
BlackFly
Registered User
KVSF, VT
I have a 1981 K model with the Kenmore GW kit. Could the four tank issue be getting confused with the four fill caps found on the long range fuel tanks? Mine has two fill caps per 44gal tank which supposedly helps when on floats. Are we talking about a new STC that will increase my GW beyond where it already is? Always thought it frustrating to have the same airplane as the 185, but with the lower GW.
Stan
Stan
Dough Head
Registered User
4AK6/DVT
Mine is a 1975 180J model with the Kenmore 3190 STC and the Monarch tanks mounted just outside of the factory tanks for a total of 96 gallons.
Dave Calkins
Registered User
Anchorage, Alaska
The ART/Wing-X wing extensions are about 5 grand for the kit and take about 40 hours to install. They take the early 180's to 2950 gross. They are actually doing something that makes the airplane a better flyer at the higher weight.
aktango58
FRIEND
18AA
Re: Gross weight
Pull off tail, rivit in plate. Takes a day.
Looks like you get took, so simple. But, does change the feel of elevators. I know of folks that had earlier models put a .040 doubler like the STC just for the added strength on the tail.
But that guy worked the bird pretty hard
and asked it to do stuff beyond what it was designed. 
Today, I would suggest the wing extentions and the doubler. Big difference in the way the plane flies.
slowmover said:
Pull off tail, rivit in plate. Takes a day.
Looks like you get took, so simple. But, does change the feel of elevators. I know of folks that had earlier models put a .040 doubler like the STC just for the added strength on the tail.
But that guy worked the bird pretty hard
and asked it to do stuff beyond what it was designed. Today, I would suggest the wing extentions and the doubler. Big difference in the way the plane flies.
I installed the GW increase on my J-model in 1990. There was a pretty significant number of changes later in the J-model, starting at serial number 18052384, so not all J-models needed the same things added per the Kenmore STC.
Since I wanted to operate on floats, I needed to replace the under-floor rudder-aileron interconnect springs and install a non-linear return spring kit in the top of the fuselage, a foot or so back from the nose of the fin. This entailed riveting in a doubler plate and brackets for the pulleys, springs, and cables to rudder bellcranks. You can see if a 180 has this or not by looking for a rectilinear array of rivets on top of the fuselage.
Later model 180s had the bigger fin; it's a common misconception that only 185s had the big fin. I had to get the big one for the STC and was lucky to find a new one still in a crate. I don't think a new one could be found today. And the STC also allowed a service kit to be installed that added more fin area up front, to make an earlier fin look like a later one. Those kits too have dried up.
Jerry Rader at Kenmore (who had a hand in obtaining the STC) said the argument used for the horizontal spar doubler was that they compared the 180 and 185 airframes and found the only difference was this doubler plate, so argued (successfully) that the 180 should be able to carry more weight if that plate were installed. The rest of the mods in the STC were likewise to make the 180 look like a 185.
I installed the STC because everyone "knows" a 180 will haul a lot; having the STC makes it legal. And the big fin allows you to legally get rid of the triangle fin on bottom of fuselage when operating with 2960s. (Most of those were eventually removed anyway since they were very prone to dock rash).
Since I wanted to operate on floats, I needed to replace the under-floor rudder-aileron interconnect springs and install a non-linear return spring kit in the top of the fuselage, a foot or so back from the nose of the fin. This entailed riveting in a doubler plate and brackets for the pulleys, springs, and cables to rudder bellcranks. You can see if a 180 has this or not by looking for a rectilinear array of rivets on top of the fuselage.
Later model 180s had the bigger fin; it's a common misconception that only 185s had the big fin. I had to get the big one for the STC and was lucky to find a new one still in a crate. I don't think a new one could be found today. And the STC also allowed a service kit to be installed that added more fin area up front, to make an earlier fin look like a later one. Those kits too have dried up.
Jerry Rader at Kenmore (who had a hand in obtaining the STC) said the argument used for the horizontal spar doubler was that they compared the 180 and 185 airframes and found the only difference was this doubler plate, so argued (successfully) that the 180 should be able to carry more weight if that plate were installed. The rest of the mods in the STC were likewise to make the 180 look like a 185.
I installed the STC because everyone "knows" a 180 will haul a lot; having the STC makes it legal. And the big fin allows you to legally get rid of the triangle fin on bottom of fuselage when operating with 2960s. (Most of those were eventually removed anyway since they were very prone to dock rash).
captainron55746
Registered User
Hibbing, Minnesota
We have a 76 J model (18052689) and put the GW kit in when it came out. I was told that with that plate in the only difference between the 180 & 185 airframe was the lift struts. The Struts are a little bigger on the 185. Ours was a factory seaplane and has the big tail. I never compared the rivet pattern on the wings to see if there is something there, but Iwill look next chance I get!
Captain Ron
8)
Captain Ron
8)
skywagon8a
MEMBER
SE Mass MA6
captainron55746 said:
There is also a doubler along the leading edge of the stabilizer on the 185 which is not on the 180. The optional rubber abrasion boots cover the doubler. This is applicable on s/n 18502311 and up. This from the 180/185 parts catalog. Also from the same catalog fig.5, there is only one wing for both 180/185. No difference.
Dave Calkins
Registered User
Anchorage, Alaska
Re: 180
Then, Slowmover, you have learned that a lightweight early model is the most beloved.
Even better would be an early model with a big motor.
Even saying this, it has been demonstrated that a "not so light" (mid-1700's) early model with an O-470R ("only" 230 HP) was able to post the shortest pair of takeoffs at Valdez this year. The same airplane with two guys, half fuel, and weekend camp-gear demonstrates less than 200 foot landings.
slowmover said:
Then, Slowmover, you have learned that a lightweight early model is the most beloved.Even better would be an early model with a big motor.
Even saying this, it has been demonstrated that a "not so light" (mid-1700's) early model with an O-470R ("only" 230 HP) was able to post the shortest pair of takeoffs at Valdez this year. The same airplane with two guys, half fuel, and weekend camp-gear demonstrates less than 200 foot landings.
slowmover
FRIEND
Little Rock, AR
180
Dave, I got the message on early model 180s, but I have a slightly different mission in mind than many Alaska guys. I am a lower-48 guy right now and I want a solid IFR cross-country platform with some off airport capability as opposed to an off-airport platform with some IFR capability. Therefore, I am looking for a late model 180 with stock wings, a stock engine, a factory float kit, and long range fuel. I plan to run 8.50s on it which will allow me to go about anywhere I would conceivably go, and I can always add the other stuff later. That doesn't mean that it isn't all good advice!
You put skis on my cub in 2001. I sold it to a guy in Anchorage so it is coming home where it belongs. An Alaska-modded Super Cub makes about as much sense in Arkansas as a vegan at a pig roast!
Dave, I got the message on early model 180s, but I have a slightly different mission in mind than many Alaska guys. I am a lower-48 guy right now and I want a solid IFR cross-country platform with some off airport capability as opposed to an off-airport platform with some IFR capability. Therefore, I am looking for a late model 180 with stock wings, a stock engine, a factory float kit, and long range fuel. I plan to run 8.50s on it which will allow me to go about anywhere I would conceivably go, and I can always add the other stuff later. That doesn't mean that it isn't all good advice!
You put skis on my cub in 2001. I sold it to a guy in Anchorage so it is coming home where it belongs. An Alaska-modded Super Cub makes about as much sense in Arkansas as a vegan at a pig roast!
Dave Calkins
Registered User
Anchorage, Alaska
Hey, I said "most-beloved". As in "...gee I wish I never sold that airplane...".
Your mission could be handled by a Bonanza. There were several working beaches for years in Alaska.
Your mission could be handled by a Bonanza.
There were several working beaches for years in Alaska. 
Shadow
PATRON
Texas
180 Aux Fuel Tank
I found a 180 that interests me but it has something that I've not seen in the 5 or 6 airplanes that I've demo'ed. In the hat rack area is a Met-Co-Aire 13 gallon fiberglass fuel tank. Really cut down on the vertical area of the baggage compartment. I didn't look at the weight and balance to see what happens with 78#s of fuel back there. Without removing the headliner I couldn't see how it was installed - to see if it could be removed -inspected or repaired if necessary. Any of you 180 guru's familiar with this? Otherwise it looked like a good airplane.
I found a 180 that interests me but it has something that I've not seen in the 5 or 6 airplanes that I've demo'ed. In the hat rack area is a Met-Co-Aire 13 gallon fiberglass fuel tank. Really cut down on the vertical area of the baggage compartment. I didn't look at the weight and balance to see what happens with 78#s of fuel back there. Without removing the headliner I couldn't see how it was installed - to see if it could be removed -inspected or repaired if necessary. Any of you 180 guru's familiar with this? Otherwise it looked like a good airplane.
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Aktahoe
Registered User
Truckee, Alaska
I have a 53 -180 with the O 470K in her. If anyone remembers Stancils old 180 (the white one, she has been mine for the past year or so). I love the plane and it flies like a cub..(well almost). It has the Monarch tanks and she weighs in at just under 1700lbs. Really curious about the ART/Wing-X mod. I am already getting off in less than 200' at 6000'. Curious how much are they really going to improve her performance? She is a dream now? Am I silly for thinking about these? Also how much more wing is going to be added. She may not fit into the hanger if I had it done to her. She also has the Horton with the VG's. Will the Horton be extended or need to be removed? Crazy questions here, I just dont know much about the ART/Wing-X mod and remember Stancil saying that it would be great mod for the plane.
Thanks
Thanks
aktango58
FRIEND
18AA
Drake in Haines loves his x-wing.
You will want to extend the STOl kit, otherwise big holes in the wing where the kit attaches
I will bet that the 200' takeoff is when very light. Try that with a load, that is where the performance comes in.
Wings do get long. 40' hanger doors get tight, as I thought the x-wing makes it around 41 feet... (I can not remember exactly). If your hanger is wide enough, push plane nose first off center into the door, then spin the tail around and the wing on the outside of the turn will enter the hanger, (judge so that it rotates to the side wall), and end up beyond the edge of the door. Finish the rotation pushing the other wing back inside the door and it will go.
You will want to extend the STOl kit, otherwise big holes in the wing where the kit attaches
I will bet that the 200' takeoff is when very light. Try that with a load, that is where the performance comes in.
Wings do get long. 40' hanger doors get tight, as I thought the x-wing makes it around 41 feet... (I can not remember exactly). If your hanger is wide enough, push plane nose first off center into the door, then spin the tail around and the wing on the outside of the turn will enter the hanger, (judge so that it rotates to the side wall), and end up beyond the edge of the door. Finish the rotation pushing the other wing back inside the door and it will go.
