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135 hp conversion

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  • #16
    Re: 135 hp conversion

    Bob Gustafson,

    I also flew a J-3 without cowl with 0-290, while I was doing Ag work for Gene Phillips in Columbia MS in the mid 60's. Had a Sorreensen Unit. It was saftied on, no release, because the pilot from the previous year had jetesoned it to get over trees and Gene didn't want to loose another. Later that year, I totaled it by catching a barb wire fence at the end of a cotton field. Walked away, but the J-3 was history.
    Yellow Duck


    • #17
      Re: 135 hp conversion

      Hello all,
      I spoke to the FAA yesterday. They thought that getting the 135 hp approved again in a t-cart would be so difficult that it could be considered impossible. FAA said that many have been approved in error in the past because they don't allow for sufficient fuel flow to the engine. Supposedly, the FAA requires 150% of full throttle fuel flow in the stall attitude. Supposedly that would require a consistently full nose tank to make enough pressure to have that kind of flow. I don't know why a guy couldn't just ditch the nose tank and install sizable wing tanks like every other airplane with a 135 hp or greater engine (citabria, PA-18, PA-22, etc).
      The funny thing to me is that there are several of these planes already out there flying that do just fine! That should be enough for it to be approved if done the same way as the existing ones.

      About the engine weights. Myself and others have done a little research on that, and it depends on what accessories you've got bolted on the engine, but it appears that the 135hp is about 100 pounds heavier than a 65hp engine. Thus, if you had a 700 lb 65hp, you should be able to have an 800 lb 135 hp. especially if the interior is absolute minimum and there is no electrics.

      About the 135 hp J3- a freind of mine currently has one of those and has flown it over 100 hrs a year for the last 6 or 7 years. He does all the off field stuff with skis and floats that I do. He has no counterballance of lead in the tail, no problems with violent stall, no problems with fuel burn duration (largish wing tanks). He does have issues with engine rebuilds because the 135hp is a fairly obsolete engine. He gets great performance and pretty much does what most of the supercub drivers can do.

      Thanks for your input on the 90 and 100hp. I agree with all the points you made, and in light of the FAA's idea of american freedom, I will likely end up with a 90 or 100hp. My main motivation is the engine and airframe available to me are such a good deal and seem like a wonderful combination. Its probably like the Reeces guy that dropped the chocolate into the peanut butter and thought damn- thats a great idea!
      PS- what STC do you have for the 90 or 100 hp? the Gilberti?



      • #18
        Re: 135 hp conversion

        Just more questions:

        Taylorcraft was building a 180hp model. What tanks were they using, and what size fuel line?

        The Swick (clipwing) plans call for a C-85 all the way up to 180hp.
        Above 100hp they call for a 3/8" fuel line, two 6 gallon wing tanks in each wing, and a header tank that is about 1 gallon, located on the boot cowl as low as possible. You also need 2 fuel pumps with this operation.

        Just my thoughts:
        I just test hopped a rebuilt L-4 (military J-3) with an engine from Don's Dream Machines in GA. Witnesses said it didn't even roll before it was airborne. It rolled a little bit, I was flying it, but not much. Empty wt. with oil = 782lbs.
        The engine is made from:
        0-200 Case
        0-200 Crank
        0-200 Cylinders/Pistons
        Cam ? I think it's C-90 but not sure.
        Anyway, it's STCed to a C-85-12, however this one has a -8 backplate.
        No place for a starter or Generator.
        Dynos out at 97HP.
        I know, I'm talking about a Cub, but now back to Taylorcraft.
        This same engine mounted on a basic (meaning no electrics and no fancy stuff on the inside) airframe, should be one of the better performing Taylorcrafts. You could do the Harer/Gilberti STC for a BC12D-85, which beefs up the wing attach fittings and installs a fuel vent system, with one or two wing tanks. Thats it. NO FAA INVOLVEMENT. Every thing is STCed.
        Like I said, Just my thoughts.



        • #19
          Re: 135 hp conversion

          great input on the swick conversion and the 180 hp t-cart. A quick check of the current advertized new t-carts from the factory shows 2 models with 180 hp and 42 gallon fuel capacity. How can the 135 hp be too heavy if a 180 hp works fine?

          I really like the sounds of your 85 hp t-cart idea with O-200 guts. I've heard a little about doing that to the 85 and 90 hp continentals before, but assumed that it would no longer be FAA legal. Maybe I assumed wrong. It sure seams like that would be the best of both worlds- weight and power.

          Anybody out there know the details of O-200 guts in a C-85?

          As far as the 135 hp conversion goes, I think I'll stop kicking the dead horse. If I pursue it, it will likely be in the experimental class. (although the FAA was acting pretty inhibited on that idea too).



          • #20
            Re: 135 hp conversion


            Here is the guy that builds up the STCed engines.

            Don's Dream Machines
            200 Barry Whatley Way
            Griffin, GA 30224

            His name is Don Swords

            Hope this helps,



            • #21
              Re: 135 hp conversion

              Tom when i had my 90 installed i had the 1500 lb wt in, done at the same time. The paperwork was a 337 and it just said we followed the gilberti stc but with deveations like a 90 instead of a 85 and so on. Back then the faa was real easy to deal with. I did get to see that t-craft in port alsworth with the 160 hp motor no elect,and pa 18 gear on it it had 30 inch bushwheels on it. That plane was like a rocket. there is 5 or 6 t-crafts up here with the 150 or 160hp motors and every now and then i see one for sale. but its been a few years. A frind of mine here in wasilla at anderson lake sold a nice 135 hp t-craft a while back for 25 i almost bout it but it sold quick. The faa up here is so strict anymore on any kind of motor swap without a stc. I was told by the faa they wouldnt even concider it..... Ive heard of people getting 115 hp out of the 90 and 100 hp cont, motors i would like to find out as much info as i can so that when i get my overhaul done mabe i can get more hp......
              Lance Wasilla AK