JMR SPecial project. My design.

Discussion in 'Member Project Logs' started by Pops, Aug 21, 2013.

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  1. Jan 6, 2018 #121

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    Mounted the engine today. Seems like it was a long time coming. Everything went together good. You can see in the picture I added straps on the engine mount. On the Falconar F-12 plans the addition of the straps raised the engine mount from 7 G's to 9's. I didn't work the math out on adding the straps to my mount, but it cuts down the column length and increases the strength of the tubes in compression.
    Feels like I just crested the top of a hill and can finally see home on the far mountain.
     

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  2. Jan 10, 2018 #122

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    W&B coming out better than I first thought. The extra weight of the prop extension helps. If I need to I'll make aluminum washers the correct thickness to put between the engine mount and engine or engine mount to firewall to find tune the CG. On one picture you can see the tach sensor that is mount behind a prop bolt that is drilled 1/8" dia hole in the end for a magnet to turn the sensor off an on. Runs on 9 volt battery or your 12 volt electrical system. Friend of mine has been using this for a couple years and likes it.

    https://www.ebay.com/itm/Blue-4-Dig...199067?hash=item1a11c3df5b:g:E6EAAOSwxH1UFwfB
     

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    Last edited: Jan 10, 2018
  3. Jan 26, 2018 #123

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    Looks like I will be able to carry up to about 40 lbs in the rear baggage area at this time but the final W&B will tell the tale.
    Last couple of fuel line fitting finally got here, and finished hooking the fuel system up. Separate off/on valve for each wing fuel tank. Same fuel system I used on the SSSC and I like it. I used rear and fronts fuel tank outlets as in the Bearhawk and my SSSC.
    Getting material together to start making the fiberglass cowl. Using a 9.75" dia spinner from AS. I will have to order more epoxy and fiberglass cloth. I have some of each, but not enough to do the job.
    I did a rough drawing of the cowl to work out the design. I think it will look good with the rest of the airframe.
     
  4. Feb 10, 2018 #124

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    Picture of the sight fuel gauges. I put some thin aluminum house flashing behind the gauges and white model airplane trim monocote behind the clear tube so I can see the fuel level better. I need to contact cement the leather circles yet. After the phase 1 test flying is over I would like to install a gray wool headliner. Aircraft Spruce sells it by the yard. Easy to install and shrink with a fine mist of water from a spray bottle and slowly dry with a heat gun.
    At this time I'm painting the walls of the office room in the hanger. When I'm finished I plan on starting the construction of the fiberglass cowl.

    Also picture of the baggage area with a aluminum box 20"x 11"x 12" deep. Picture of the fuel valves on each side. Need to label the off/on of each valve and do the labeling on the instrument panel. I paint a red mark on ever nut and bolt , fuel fitting, etc then I do the final torque so nothing will be missed.
     

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  5. Feb 13, 2018 #125

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    Started the fiberglass cowl today. Covered the engine with plastic. Made a plywood plate the size of the backplate of the spinner, used 4 wood blocks to space a plywood ring that is the front of the cowl. Glued the first foam blocks to the plywood ring. I'll be covering the engine with foam blocks and carving and sanding to shape about 1/16" undersize. The cowl will split at the center of the thrust line of the engine, top and bottom half. After using 2 ply of fiberglass on both halfs, I will take apart and carve the inside foam to a thickness of about 3/4" and sand smooth, epoxy in hardpoint hardwood blocks and use 2 ply of fiber glass cloth on the inside. I made a fiberglass cowl the same way for my Falconar F-12 and it came out very strong and light. I could stand on it with no problem.
     

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  6. Feb 14, 2018 #126

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    Adding more foam. The jar of tig welding rod ends works good to help hold the foam together until the epoxy sets up. Try to put the epoxy below the level that you will be carving and sanding, it will make life easier.
    Use anything you can, rubber bands, tape, etc, to hold the foam. When I get to the carving and sanding, hopefully I can catch a warmer day where I can pull the airplane outside because of the terrible mess it makes.
     

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  7. Feb 26, 2018 #127

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    I haven't got much done in the last few days. The bottom foam will have a little more bow into it when I epoxy the foam together. When I get the top and bottom of the cowl shaped, (its splits in the middle) I'll fiberglass the outside of the foam. Then take the bottom and top half apart and carve the inside of the foam for about 1/2"- 3/4" thickness, epoxy the hardwood block hard points in and fiberglass the inside.
    I have it all planed inside my head, just need to get it out :)
    The front air opening are about 32 sq " on each side at the present time. Need to work out the air intake and exhaust size before I get any farther along.
     

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    Last edited: Feb 27, 2018
  8. Mar 7, 2018 #128

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    Not spending much time on the JMR the last few weeks. Life happens. Still epoxing foam together and carving and sanding. At least its looking a little more like a cowl.
     

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  9. Mar 30, 2018 #129

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    Did a little fiberglass work on the top half of the cowl today. Dana was here yesterday and we both agreed that the bottom is just to "Chuckey" ( not streamlined enough in redneck talk :) ). If it doesn't suit me I just have me to blame. Think I'll do more carving and sanding on the bottom half. I knew I had some E-Z Poxy left over from a few years ago and found it. Looks like it will make about 2/3 of a gallon when mixed together. I know the fiberglass cowl will be resin rich and a little heavier than if it was vacuum bagged but a little more weight on the nose will help with a little more baggage weight limit in the W&B. I'll be making fiberglass bumps on the side of the cowl to clear the valve cover pans. The 4" prop extension really helps the looks of the cowl.
    Also have to make the housing for the airbox and the lower lip in front of the air exit before fiberglassing the lower half of the cowl.
     

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    Last edited: Mar 30, 2018
  10. Apr 15, 2018 #130

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    Separated the cowl along the parting lines. Now need to carve the foam on the inside to about 3/4" thick and fiberglass. The weight of the foam removed will be close to the weight of the fiberglass added so shouldn't be much of a weight change. There will be a weight increase from the hardwood hard points and filler and paint. At the present time the weight is a little over 3 pounds, so thinking the final weight will be a little over 4 lbs for the final weight of the top of the cowl.
     

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    Last edited: Apr 15, 2018
  11. May 10, 2018 #131

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    I had an old beat up Cont airbox that I repaired but it had seen it's better days. Yesterday, Dallas ( old friend of about 40 years and helping each other build airplanes for at least 30 years) stopped by and gave me this Stainless Steel airbox that he scratch built about 30 years ago for a JR Ace that he built but never used. Very, very nice. I'm at the point where I need to cut a hole in the bottom of the lower cowl for the airbox.
     

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  12. May 25, 2018 #132

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    Painting a bathroom today so no work on the cowl and also have yard and garden work to do. Need to do the micro over the fiberglass and a lot of sanding and I hate sanding. Need to flush rivet nut plates on the side of the firewall to mount the rear of the cowl. Was planning on using cam-locks but decided to just use 8/32 SS machine screws with countersunk SS washers epoxied into the side of the cowl. Also need to make the fiberglass bubbles over the valve cover pans. I'll get it done but no time table on the job. I did get the mixture and carb heat cables run.
     

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  13. Jun 16, 2018 #133

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    Building the bubble over the valve cover pans. Use plywood faces between the top and bottom half of the cowl and cowl clearance bubbles. After shaped they will be covered with fiberglass inside and out. Airplane building has gotten slow with the summer weather with lots of other things that need done.
    BTW-- the engine has 1.8 degrees right thrust, just a guess. Hope I'm close. If not the rudder trim tab will take care of it.
    Also need to put an oil door in the right side. Remember that Dan.
     

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  14. Jul 2, 2018 #134

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    Go to the thread " Don't have an artistic bone in my body, need help" , for the help I received on designing the cowl. Under Hanger Flying.
    Thank you very much.
     

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    Last edited: Jul 3, 2018
  15. Jul 7, 2018 #135

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    Hard to believe I have been working on the fiberglass cowl since the middle of Feb. But I have been busy mowing grass, painting rooms in the house, installing new flooring in the house, planting a garden, etc. Working on building the oil door now. When I finish the door, just need to do all the finish sanding and filling before primer and paint. I hate sanding, so that will be slow.
    Received the spinner I order from AS, dropped shipped from the manufacture in 3 weeks. I have to cut the cutout for the prop in the spinner, nice to see they included the article by Tony Bingelis on doing the job correctly. Tony's books on building tips are worth every penny. Spinner looks very good.
     

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  16. Jul 12, 2018 #136

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    I didn't forget the oil door for the top half of the cowl. Used a swing out hinge like on your auto fuel door. Works good. Now to get back on putting on more fiberglass cloth and finishing and painting. Need to make the fillet bigger and then not much to do and I'll have the top half ready to prime.
     

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  17. Jul 15, 2018 #137

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    I temporary taped the spinner on and I think it helps the looks of the cowl.
     

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  18. Jul 25, 2018 #138

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    Little up date on the slow progress of the fiberglass cowl. I have been spraying black primer on the top of the cowl and block sanding to find the low spots. Looks like it ready for the first full coat of primer. (Did I tell you I hate sanding) :)
    I still have some low spots on the lower half of the cowl that needs filled with epoxy surrey, ( that is epoxy mixed with micro-balloons) to be like stiff whipped cream or how you like it. I just mix the epoxy and then start adding the micro until its what I want. Maybe 6 micro to 1 epoxy by volume. If it will stand up when pulling the mixing stick out, its good for me. After I get it as smooth as I can block sanding the filler then spray the surface with black primer and block sand to find the slightly low areas. If you can close you eyes and fell any variation with your finger tips, it will show up after the paint job.
    Going to work on the cowl a couple hours in the morning and then back to painting the dining room and kitchen in the house for the wife. ( Think I would rather sand ) :(
     
    Last edited: Jul 25, 2018
  19. Jul 29, 2018 #139

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    Last coat of primer for block sanding, found a couple places to fix with a little film of Spot and Glaze and the top will be ready for the real first coat of primer and then paint. Maybe I'll have to bottom up to this point by the next weekend.
    Spent about 5 hrs working on cutting the spinner slot for the prop, not easy, instructions say make a cardboard pattern 1/8" under size and cut with snips and then file for a 1/16-1/8" gap all around. The larger slot in front of the leading edge is required to get the spinner on the prop, I will make a separate cover of this latter. After I get the JMR flying for a while I will have a base on performance and then I plan on start reducing drag with wheel pants, wing strut fairings, Landing gear fairings, etc. That way I will know the improvement of each.
     

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  20. Aug 5, 2018 #140

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    Fitting the cowl to the firewall for the 1/4" gap between the spinner backplate and the front of the cowl. I purposely made the firewall end of the cowl a little long so I can trim material off to get the 1/4" gap between the spinner and nose of the cowl. Had to trim 1/4" off. Now need to located the holes for the screws to mount the cowl while centered on the spinner. I will be epoxying in SS countersunk washers for the screws to mount the cowl so I need to get the mounting all finished before starting the painting.

    Looks like I'm going to have to fix the flat tire on the lawn mower. :)


    I have the rear edge of the cowl trim and marked for the mounting screws, front gap between the spinner and cowl where I want and top and bottom of the cowl together and held tight and in position with the red strap. Now time to drill the mounting hole in the fiber glass and in the firewall flange. Will be flush riveting nut plates to the inside of the firewall flange. When the cowl is mounted I will get back to block sanding, filling the surface of the bottom getting it ready to paint.
     

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    Last edited: Aug 5, 2018
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