VP-1 Templates, G Code and SolidWorks files

Discussion in 'Wood Construction' started by FritzW, May 31, 2019.

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  1. Oct 8, 2019 #21

    FritzW

    FritzW

    FritzW

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    You could use wood struts on a VP but you'd have to do the engineering and you sure wouldn't want to get the math wrong.

    I would imagine there are better options though. Maybe round steel tubing with wood fairings?
     
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  2. Oct 8, 2019 #22

    blane.c

    blane.c

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    Mild steel sheet could be formed, rivet or weld trailing edge, also mild steel brazes well at a lower temperature than welding and Brownells Hi Temp High-Force should be much more than adequate for strength and flows at 640*F - 650*F. Just need to do or have someone do engineering so it is same strength as the preformed 4130, yes it'll weigh a bit more not much considering size. Or aluminum but more expensive.

    Annotation 2019-10-08 125932.png
    Annotation 2019-10-08 125932.png
     
  3. Oct 8, 2019 #23

    mullacharjak

    mullacharjak

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    Did I forget to mention that we do have ERW cold rolled mild steel 1010 tubing in various shapes but no streamlines..The tubes are already welded.Good welding equipment is also available like TIG/MIG. Aircraft grade material like 4130/2024/AN hardware/T88/Aerolite etc is not.
    I have the VP plans since long.I even have the running 1600cc vw engine which I rescued from a VW bus long long ago.It has the 54x33 prop from the eric clutton book.Runs good.

    Note. Brownells hitemp hiforce not available.
     
  4. Oct 9, 2019 #24

    FritzW

    FritzW

    FritzW

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    There are charts that show the round tube equivalent for stream lined tubes. You'll probably have to do some adjusting to account for the difference between 4130 and 1010. The tube info on West Coast Piet would be a good place to start.
     
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  5. Oct 9, 2019 #25

    mullacharjak

    mullacharjak

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    FritzW Thanks for the tube info.
    I am assuming a compression of 3000 lbs in the front strut at max load. A rectangular mild steel tube 1x2 inch 19
    guage wall thickness will take 4000lbs of compression. 1 3/16 x 2 inch 19g oval tube can take 3600lb.
    Never thought mild steel erw tubes could do the job.Whats the vertical max lift reaction at the strut attach point?
     
    Last edited: Oct 9, 2019
  6. Oct 9, 2019 #26

    FritzW

    FritzW

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    Take this with a grain of salt, I don't have my books in front of me.

    But isn't it just: gross weight X 6.6G / two wings? ...minus load distribution on a two spar wing (I don't know if your supposed to subtract wing weight but this will give you the worst case)

    750 X 6.6 = 4950
    4950/2 = 2475

    Even if you don't subtract for load distribution on a two spar wing and use 2475 for the vertical reaction at each strut attach point it wouldn't be hard to design for. (of course the compression in the struts will be higher than the vertical force at the strut attach points)

    ...I have no doubt someone will correct me if I'm wrong
     
  7. Oct 9, 2019 #27

    FritzW

    FritzW

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    Is that taking the column load into consideration? VP-1 struts are 50+ inches long and there are no jury struts on the rear struts, ...unless you add them
     
  8. Oct 10, 2019 #28

    mullacharjak

    mullacharjak

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    Yes thats column or compression limit for a 53 inch long piece of that shape.I think 4.4g should be enough.
    4.4x750lb=3300/2=1650 lbsx75%=1237lbs/sine 22degrees=3300lbs compression front strut.
    I hope I did the conversion correctly as i dont know much about math.
     
  9. Oct 10, 2019 #29

    FritzW

    FritzW

    FritzW

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    The VP was designed for 4.4G with a 1.5 factor of safety. (4.4 limit, 6.6 ultimate). ...the U.S. utility category
     
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  10. Oct 10, 2019 #30

    Riggerrob

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    Are you sure that dividing gross weight by 2 is wise?
    Aren't struts supposed to be able to hold a variety of G-loadings even while rolling?
    Try to imagine the worst possible loading going from maximum negative Gs to maximum positive Gs while rolling and side-slipping, then build struts a bit tougher. .. at least to the next larger gauge of tubing.
    Jury struts can also vastly reduce the risk of struts buckling under compression.
     
  11. Oct 10, 2019 #31

    mullacharjak

    mullacharjak

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    The VP 1 is non aerobatic and one is supposed to fly straight and level and only 30 degree banks(ok 45 deg!).Worst case would be a gust which one hopes will never come!
     
    Last edited: Oct 10, 2019
  12. Oct 11, 2019 #32

    blane.c

    blane.c

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    ?
    ?
     
  13. Oct 11, 2019 #33

    FritzW

    FritzW

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    errr.. yes it is. It's limited to "gentleman" aerobatics like loops and rolls but it's not "non aerobatic".

    errr.. no they're not. I don't know where you got that from but sure it wasn't the VP-1 Pilots Handbook


    The gust will come, guaranteed.
     
  14. Oct 11, 2019 #34

    mullacharjak

    mullacharjak

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    Apologize if I stirred a hornets nest. Never read about anyone performing Loop the Loops in a VP except probably Bill Beatty the test pilot in the VP handbook which I have long lost.
    I would rephrase my previous statement by saying that would be how I would fly a VP if ever I had one.
     
  15. Oct 11, 2019 #35

    blane.c

    blane.c

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    I agree that gusts will come. Many many gusts.
     

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