CriCri MC-15 in NZ

Discussion in 'The light stuff area' started by MadRocketScientist, Jun 19, 2009.

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  1. Oct 22, 2009 #61

    EzyBuildWing

    EzyBuildWing

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    I wonder if the little Wee Bee was as complex to build as the Cri Cri?

    See pictures of Wee Bee here:

    How about a simple fuse of constant 2'3" x 1'0" constant cross-section( ie: a box) with Cri Cri canopy and biplane-wings ( Quickie style arrangement), and Cri Cri tailplane and and engines and trike-gear. Everything is metal of course, and overall dimensions are same as Cri Cri. For simplified building, wings would be built whole with no dihedral.

    Could be called a "Cri Cri Quickie" or "Cri Cri Bipe...fast-build"

    A single HKS motor could power it if desired.

    Anyone care to comment?
     
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  2. Oct 22, 2009 #62

    MadRocketScientist

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    I think you would find that the engineering involved in the new design would far exceed the time to build a CriCri in the first place. A Hummelbird may be a better and faster build option. It would also be cheaper too.

    Shannon.
     
  3. Oct 28, 2009 #63

    grostek

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    Hi Shannon,

    Thankyou for taking the time to post your build progress here.

    I had a look at the flap selector mechanism yesterday and decided to jump right in and do a CAD drawing of it. then noticed that Mr. Columban recommends that a builder should wait with the positioning of the flap setting notches at 3, 12 and 29 Degrees .
    So I drew a big 140mm Diameter circle, constructed the bend angle onto this and drew the notches.

    All this after determining the position of flap lever mechanism on the spar box, flap lever shape, Flap gate position on the bulkhead.

    My question being have you drawn the flap mechanism and have you worked out the notches on the flap gate or will you wait until you have it all assembled in the airframe?

    Kind regards,

    Gunter Rostek
     
  4. Oct 28, 2009 #64

    MadRocketScientist

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    I will wait until the flaps are all assembled before making the flap selector. There is some adjustment in the flapperon control rods but I think it will be easier to make it last.

    Shannon.
     
  5. Oct 28, 2009 #65

    grostek

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    Thanks for the info

    Kind regards,

    Gunter Rostek.
     
  6. Nov 11, 2009 #66

    pie_row

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    Good stuff.
     
  7. Dec 12, 2009 #67

    MadRocketScientist

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    Back into it, I have missed out on a lot of building over the last couple of months as I have been busy with other projects.

    I have been continuing work on the main landing gear support blocks I could have made them on the CNC but I did them on the mill drill. I have changed the lower bolts to countersunk ones as the heads would stick out into the airflow. The bushings are urethane and machined from urethane rod stock, ended up taking longer but it only cost $40 for enough urethane rod to do two aircraft.

    I also should have taken more pictures of the process.

    Shannon.
     

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  8. Jan 11, 2010 #68

    MadRocketScientist

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    Time for another update, Not a lot has been happening with the CriCri build over the Christmas rush, I hope to do more work on it in the coming weeks. I have had the plans for well over a year now and it is fast coming up to 1 year of actual construction (started sometime Feb '09)

    I have almost finished the landing gear mounts, just a few CNC washers to go. I have also started work on the top of the spar box, the associated seat mounts and the seatbelt attachment.

    I have drawn the CAD file for the set base and I hope to cut this in the next few days. First I need to double check it before I cut it to make sure I am happy with it.

    Apart from that a very disappointing amount of progress for the last three months.

    Shannon (slow progress? who me?:ermm::nervous:)
     

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  9. Jan 11, 2010 #69

    MadRocketScientist

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    I cut the seat base tonight, had to make a few changes to the drawing before I cut anything. I also some of the washers for the landing gear clamps and some other parts out of the 0.040 2024 sheet. I hate wasting metal when its not necessary so I cut some more parts for the second CriCri out of the waste areas. (sorry no pics of that)

    I made a test seat base on the CNC out of a very 'expensive';););) material (scrap cardboard:lick:) Folded it up and it fitted rather well so I cut the real one out of the 0.040" 2024. Somehow its a fair bit harder to fold than cardboard so I will have to head down to the airfield and talk nicely to Pat and use his folder.

    There is also a slightly blurry pic of the confor foam 'to be seat cushion' that I will cut down to fit. The foam weighs a fair amount for what it is but I can live with the (small amount of) weight for the creature comfort. I have been using the foam on my computer chair for the meantime and sitting on a chair without just feels wrong now. Sooo comfortable.

    Shannon.
     

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  10. Jan 13, 2010 #70

    MadRocketScientist

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    I should also include a link to the Confor foam, its available at Aircraft spruce here
    CONFOR FOAM SEAT CUSHION from Aircraft Spruce
    It can also be purchased through Aircraft logistics here in NZ.

    I am using the 1" thick foam for my seat. I think I will double it up in the very bottom of the seat well for extra comfort. I can fit under a standard height canopy and as I have made the canopy frames 30mm higher the extra thickness shouldn't be an issue. The foam tends also to thin a bit as it molds to your body. The crash protection of the Confor foam is an added bonus if the worst should happen.

    Now to start the search for a good flame resistant seat covering material.

    Shannon.
     
  11. Jan 13, 2010 #71

    needswings

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    Because you eat a lot of curry? :gig:

    Seriously though, I love the output from the CNC machine.

    Any idea how much time you think your saving by having the CNC machine doing the cutting, drilling etc, given that you've also got the time cost of putting the plans into a CAD program?
     
  12. Jan 14, 2010 #72

    MadRocketScientist

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    Haha, didn't see that one coming;) I don't even like curry, way too hot for me.

    I am not sure how many hours I will save, I would guess I have only spent about 400 hours actually building and about the same again on the CAD drawings. I am making things take longer by using flush solid rivets, the looks will be worth it though. If I make myself a second CriCri (turbines or electric anyone) there will be a huge time saving then.

    Shannon.
     
  13. Jan 14, 2010 #73

    needswings

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    yeah, thats about what I was guessing at - about the same for a single build, but very benificial if you want to do more than one. Thanks for posting everything here - its very informative.
     
  14. Jan 14, 2010 #74

    Mac790

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    Don't forget about parts quality, I bet Shannon's CNC parts have higher quality than hand made parts.

    Seb
     
    Last edited: Jan 14, 2010
  15. Jan 14, 2010 #75

    MadRocketScientist

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    I think it may save around 500 hours overall, but then that will depend on how long I spend on things like the riveting, Pop rivets would end up a lot faster to put in than solids. Countersinking and dimpling is really going to eat up some hours too.

    I 'could' hand make parts close to CNC quality but it would be very tedious and take at least 10 times as long. Why I would want to would be anyone's guess:ponder:;). I have already spent hours marking out rivet locations to do the CAD drawings.

    A few more pics from last night. I rolled the front edges of the seat tray. I had first tried folding it on the folder but I should have used a radius bar. The attempt wasn't really successful. I decided to make up a form block to roll the edges. They are a bit tricky due to being a partial conical shape. The first form I carved had a radius the was too big so I had to make a slightly smaller one. The second one worked better but the curve still needed a bit of gentle persuasion with the rubber mallet.

    Shannon.
     

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  16. Jan 19, 2010 #76

    MadRocketScientist

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    I flanged the elevator ribs today. I decided to show a progression of how they are done. Usually the ribs are flanged without flutes but the fluting makes things a lot easier.

    First I had to radius the edges of the form blocks to allow for the bend radius to stop the aluminium cracking. I also sanded all the edges of the ribs to remove any tooling marks. Then I removed the PVC film from off the aluminium and cleaned the printing off using methylated spirits (It stops the ink getting baked on during the heating process)
    I applied the yellow soap used in the tempering process. I keep the soap in a resealable bag so that it doesn't dry out between uses. The soap needs to be slightly moist but not wet so that it covers the aluminium evenly when wiped on.
    Then I used the gas torch to heat the metal until the aluminium was an even brown color and quickly dunked edge on into cold water. The color in the photo is on the dark side as I didn't put it into the water right away. I had to re-temper that piece after taking the photo. I then bold the form blocks onto the rib and clamp the whole thing in the vice.

    The flange comes out very buckled when worked over with the mallet and hence the reason for the flutes. The plans call for shrinking of the flange, but that takes a lot longer.

    Continued next post...
     

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  17. Jan 19, 2010 #77

    MadRocketScientist

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    I marked out the flute locations using the notches CNC cut into the form blocks. Then after removing the ribs I used the fluting pliers to flute the ribs. The flanges were still not very flat at this point so I filed the flute notches on the form blocks to allow the flutes to sit in them and I gave the flanges another going over with the hammer.

    I had to make sure that the ribs were flanged opposite to each other as the holes for the pushrod attachment bracket are predrilled. The fronts of the ribs curve outwards a little but I will work on that when they are closer to being fitted. I will also have to check the flanges for a good fit to the skin when I am closer to assembling the elevator parts.

    Shannon.
     

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  18. Jan 19, 2010 #78

    MadRocketScientist

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    I also have a slight issue that someone may be able to help with. The seat mounts call for a tube to be flattened on both ends to allow bolting to brackets. I flattened one end of the tube and the edges crack (no surprises there really) I am wondering if this would be an issue at all and how to solve it.

    I may have solved the problem by filing the cracked area back to good metal when I rounded the ends.

    The control pushrods also have the ends flattened but they have inserts in the end of the tube that stop it being flattened completely onto itself. I could do this with the seat mounts but it seems to be a lot more work for something that may not be an issue at all. There is not a huge amount of force on this and it is in an area that is easy to inspect.

    Any suggestions welcome.

    Shannon.
     

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  19. Jan 19, 2010 #79

    MadRocketScientist

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    Folded the elevator pushrod bracket tonight, if you look closely the holes for the nutplates are slightly oval. I think the CAD drawing needs changing as the pilot holes were out slightly. I will have to remake the part (I also noticed that the white plate should be riveted through too, so much for reading the plans :ponder::lick:;))

    Once folded I cut the tops of the 'ears' to fit inside the ribs. Its easier to do this after its folded instead of when they are machined out.
    The base ended up with a slight curve on it from the folding process, this isn't as much of an issue as it sounds as the smaller white plate in the last two photos needs to be bonded and then shaped to fit the (curved) elevator skin anyhow.

    I don't think it will take very long to remake the bracket as I now have the jigs for folding. The aluminium block I folded it with is in the first pic.

    Shannon.
     

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  20. Jan 19, 2010 #80

    Autodidact

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    Thank you, MRS. My name is Bret, and I love this stuff!

    Also, did/can you anneal/temper the seat mount tubes?
     

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