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110 MPH Taylorcraft !?!?

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  • 110 MPH Taylorcraft !?!?

    Yesterday, after over a month of screwing around with the installation, I finally flew my plane again with the 85 HP engine. Thanks to Forum member Falcon 10 for selling me what is apparently a good engine.

    The propeller I got with it was a metal McCauley 71-50.

    With this prop, my plump arse, and 12 gallons of fuel, the airplane got off the ground a little better than my 65HP engine, climbed about as good at 2000 RPM indicated, and then proceeded to run like a Greyhound in level flight! At 2200 RPM on the downwind leg of the traffic pattern the indicated airspeed was 110 MPH. That is faster than I have ever seen any of my T-crafts cruise. It was 10 mph into the yellow arc (pre-war aircraft)!

    Considering that the max RPM on this engine is 2575, I'm afraid that at full throttle I might be causing sonic booms across California

    The reality is that at over $5.00 a gallon, lower RPM's will be far more appropriate. The tiny hard to read graph in my Continental engine overhaul handbook says that at 2000 RPM a C-85 should be burning 3.3 to 3.7 gallons an hour.

    Yesterday the airplane ran 100 MPH indicated at 2000 RPM, and 85 MPH at 1800 RPM (at 2.8 to 3.2 gallons an hour according to the graph) with that super-cruise prop. That works out to better gas mileage than my 98 Pontiac minivan!
    Taylorcraft : Making Better Aviators for 75 Years... and Counting

    Bill Berle
    TF#693

    http://www.ezflaphandle.com
    http://www.grantstar.net
    N26451 (1940 BL(C)-65) 1988-90
    N47DN (Auster Autocrat) 1992-93
    N96121 (1946 BC-12D-85) 1998-99
    N29544 (1940 BL(C)-85) 2005-08

  • #2
    Re: 110 MPH Taylorcraft !?!?

    Yup Bill...that's where the real differences between one of those "yellow" planes and a Tcraft show up best....bolt a bigger engine on a J3 and you burn more fuel.... bolt a bigger engine on a Tcraft and you go faster as well as get off the ground quicker!
    John
    I'm so far behind, I think I'm ahead

    Comment


    • #3
      Re: 110 MPH Taylorcraft !?!?

      Me too please.

      I'd like to put a C series engine in my pre-war ship for the obligatory 8000ft summertime passes.

      What steps did you take to get there. Did you also need to change your motor mount?

      STCs ala carte?

      Thx
      jCandlish

      Comment


      • #4
        Re: 110 MPH Taylorcraft !?!?

        Originally posted by VictorBravo View Post
        Yesterday, after over a month of screwing around with the installation, I finally flew my plane again with the 85 HP engine. Thanks to Forum member Falcon 10 for selling me what is apparently a good engine.

        The propeller I got with it was a metal McCauley 71-50.

        With this prop, my plump arse, and 12 gallons of fuel, the airplane got off the ground a little better than my 65HP engine, climbed about as good at 2000 RPM indicated, and then proceeded to run like a Greyhound in level flight! At 2200 RPM on the downwind leg of the traffic pattern the indicated airspeed was 110 MPH. That is faster than I have ever seen any of my T-crafts cruise. It was 10 mph into the yellow arc (pre-war aircraft)!

        Considering that the max RPM on this engine is 2575, I'm afraid that at full throttle I might be causing sonic booms across California

        The reality is that at over $5.00 a gallon, lower RPM's will be far more appropriate. The tiny hard to read graph in my Continental engine overhaul handbook says that at 2000 RPM a C-85 should be burning 3.3 to 3.7 gallons an hour.

        Yesterday the airplane ran 100 MPH indicated at 2000 RPM, and 85 MPH at 1800 RPM (at 2.8 to 3.2 gallons an hour according to the graph) with that super-cruise prop. That works out to better gas mileage than my 98 Pontiac minivan!
        Bill,when we test flew Crispy with the 0200 and 71/48 prop she was showing us around 130mph at 2450rpms however 2500 was all it would turn in level flight at full throttle. The last prop we tried before her little fall from grace was a 74/45,yes a standard pitch prop for the A65 on a t-craft. She was doing about 127mph at 2400rpms and 120mph at 2200rpms. If we cranked it up to 2550rpms we were pushing 135mph....and yes,it would red line it easy with that prop. With the same prop we were climbing 1000fpm @ 80mph with 24 gallons and 2 people each weighing in at 230lbs each. This was in 90 degree 60-70% humidity with the field elevation just under 1000feet. We were cross checking all the speed with a GPS and they were accurate. I can't wait to get her finished again.
        Kevin Mays
        West Liberty,Ky

        Comment


        • #5
          Re: 110 MPH Taylorcraft !?!?

          funny, my a-90 (round tip) 74/45 mccauly shows 90 at 2450?
          Last edited by jCandlish; 06-12-2008, 16:34. Reason: spelin

          Comment


          • #6
            Re: 110 MPH Taylorcraft !?!?

            over $5.00 a gallon
            Think yourselves lucky. In Europe, 100LL is about $15 per US Gallon

            Comment


            • #7
              Re: 110 MPH Taylorcraft !?!?

              Originally posted by jCandlish View Post
              funny, my a-90 (round tip) 74/45 mccauly shows 90 at 2450?
              It's all in the rigging...and the finish...and maybe a little in how you get everything to fit in the final assembly.....Then again it might have all been luck!
              Kevin Mays
              West Liberty,Ky

              Comment


              • #8
                Re: 110 MPH Taylorcraft !?!?

                Originally posted by crispy critter View Post
                It's all in the rigging...
                How much wash and aileron droop do you suggest?

                Comment


                • #9
                  Re: 110 MPH Taylorcraft !?!?

                  Bill;
                  I'm flying my L2 with 85HP MacCauley 71/48 prop and in the rare air of 7500 ft get 111-113 Mph at 2550 and 5.9-6.2 gallons per hour. Not that mine's a race horse... But, I could've beat Big Brown at Belmont last week.

                  I've mentioned this before: Given that the L2 has a 14 gallon tank and you must land every 90-110 minutes for gas, and that makes the cross country average speed less... point to point... with more than one extra fill-up... I get almost precisely the same speed and cost of gas as my Jeep Wrangler. My question is; "How do it know?"
                  With regards;
                  ED OBRIEN
                  Last edited by Ed O'Brien; 06-13-2008, 09:56.

                  Comment


                  • #10
                    Re: 110 MPH Taylorcraft !?!?

                    Originally posted by jCandlish View Post
                    funny, my a-90 (round tip) 74/45 mccauly shows 90 at 2450?

                    Have it repitched to 43, I can get 106 KIAS and ground speed in level flight @ 2700 RPM with a 74-43 prop on an O-200 prewar aircraft....when I was 74-46 I was 98 kts and could not get to the 2700, only 2650. Tim
                    N29787
                    '41 BC12-65

                    Comment


                    • #11
                      Re: 110 MPH Taylorcraft !?!?

                      Originally posted by astjp2 View Post
                      ....when I was 74-46 I was 98 kts and could not get to the 2700, only 2650. Tim
                      @ 2000 msl the a-75 can turn 2650, but I prefer to keep it at 2450 or less. The motor will be 70 next year.

                      My performance figures seem quite in the ballpark with yours 45" pitch and 95 statute at 2450.

                      How does your oil temp and pressure look when its above 80F outside?
                      Last edited by jCandlish; 06-13-2008, 12:44. Reason: typoos.

                      Comment


                      • #12
                        Re: 110 MPH Taylorcraft !?!?

                        Originally posted by jCandlish View Post

                        What steps did you take to get there. Did you also need to change your motor mount?
                        Apologies to the millions of downtrodden T-craft owners who have had to hear this same lengthy ranting from me already...

                        I used "option A" of the Gilberti/Harer STC. This required about half or 2/3 of the list of changes in the STC, and gives me 1280 pounds gross weight. It results in the best balance between available power, economy, and flying qualities of any T-craft configuration.

                        Per the STC I was able to re-use the original short engine mount and short cowling, but with difficulty.

                        The "reasonable" parts of the STC modifications include the upgraded spar root bushings, the welded steel plates on the upper strut fittings, and a larger fuel line from the gascolator to the carburetor.

                        But Using a verbatim reading of the STC, it also requires the installation of BOTH wing tanks, a completely Rube Goldberg (that's Heath Robinson to the Brits) re-routing and plumbing of the tank vent system, and a completely INAPPROPRIATE relocation of the wing tank shutoff valves.

                        If you choose to do this STC upgrade, there are IMHO several worthwhile deviations from verbatim that I would suggest, which I will be glad to discuss at your request.

                        As far as the existing engine mount and cowl, when I mounted my 85HP engine (which had Eisemann magnetos on it) and engine mount on the firewall, there was a NEGATIVE clearance to the back of the mags... in other words an interference. We literally had to take a small sledgehammer and indent the firewall to get room for the mags.

                        Moving the engine forward with one inch spacers would have solved the problem on the back, and created a new problem on the front. There is less than 1/8 of an inch clearance between the #4 cylinder front baffle and the inside of the nose cowl, and 1/8 of an inch between the front of the nose cowl and the trailing edge of the propeller.

                        Also, when doing the 85 HP upgrade, you will need to cut your exhaust system in half, along with the heat muff surrounding the exhaust, and patch it back together approximately 3/8 of an inch wider to fit the wider crankcase of the C-85.

                        Please trust me on this... when you do the engine change, do not waste any time trying to leave the engine mount on the firewall. You will never get the exhaust off. What I found out from recent experience removing and reinstalling the engine is:

                        First, remove all the connections between the aircraft and engine. All of them unfortunately. Then remove the nuts holding the exhaust on the engine. This is somewhat difficult to get the wrench into position. I had to remove the intake elbows from 2 of the cylinders to even get the exhaust to come off. Drop the exhaust off the studs and leave it captured by the mount.

                        Make sure everything is disconnected, including the miles of safety wire, wire ties, CHT probes, SCAT ducting, wiring, etc.

                        Attach your engine hoist and take up the weight of the engine.

                        Loosen the nuts holding the engine to the mount, so there is NO compression of the conical rubber engine vibration mounts. Leave just enough of the nut on the bolt treads so the engine mount will not fall off the engine, but make sure the engine is completely loose on the mounting rubbers... disengage the rubber cones from the engine as much as possible ! (the engine being tight on the mount applies some tiny deformation or tension on the mount, which in turn makes the bolts through the firewall very hard to get in and out. Don't ask me how many hammer blows I went through before learning this !!!)

                        Make sure to not drive the engine mount bolts back through the firewall if you can avoid it.

                        Remove the engine mount from the firewall with the engine and exhaust more or less in place.

                        Now you can remove the engine mount easily, followed by the exhaust system.

                        I hope I haven't frightened you off from doing the upgrade, it really does make a wonderful airplane into an awesome airplane. If you know ahead of time what is required, then the entire process will be far more manageable.
                        Taylorcraft : Making Better Aviators for 75 Years... and Counting

                        Bill Berle
                        TF#693

                        http://www.ezflaphandle.com
                        http://www.grantstar.net
                        N26451 (1940 BL(C)-65) 1988-90
                        N47DN (Auster Autocrat) 1992-93
                        N96121 (1946 BC-12D-85) 1998-99
                        N29544 (1940 BL(C)-85) 2005-08

                        Comment


                        • #13
                          Re: 110 MPH Taylorcraft !?!?

                          Originally posted by jCandlish View Post
                          @ 2000 msl the a-75 can turn 2650, but I prefer to keep it at 2450 or less. The motor will be 70 next year.

                          My performance figures seem quite in the ballpark with yours 45" pitch and 95 statute at 2450.

                          How does your oil temp and pressure look when its above 80F outside?

                          In Alaska I really dont see above 80 at altitude most of the year. I just redid my baffling so I will be evaluating the temps again. Tim
                          N29787
                          '41 BC12-65

                          Comment


                          • #14
                            Re: 110 MPH Taylorcraft !?!?

                            I applied for a multiple STC to install an O-200 on a short mount with the original venting of the fuel system, different baffling, 74" propeller, no gross weight increase and a spinner. I figure it will be a year or 2 for that approval. I dont like the Harer STC requirements so I am getting my own. Tim
                            N29787
                            '41 BC12-65

                            Comment


                            • #15
                              Re: 110 MPH Taylorcraft !?!?

                              Originally posted by Robert Lees View Post
                              Think yourselves lucky. In Europe, 100LL is about $15 per US Gallon
                              My God I'm sorry to hear it. That's awful.

                              Gap seals, fairings and wheel pants...?
                              Taylorcraft : Making Better Aviators for 75 Years... and Counting

                              Bill Berle
                              TF#693

                              http://www.ezflaphandle.com
                              http://www.grantstar.net
                              N26451 (1940 BL(C)-65) 1988-90
                              N47DN (Auster Autocrat) 1992-93
                              N96121 (1946 BC-12D-85) 1998-99
                              N29544 (1940 BL(C)-85) 2005-08

                              Comment

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