Help needed drawing a part for an electric jet engine

Discussion in 'Aircraft & Aviation' started by Leif Oh, Aug 8, 2005.

  1. Leif Oh

    Leif Oh Member

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    With the thread on replicating alu skins going so well, I got quite inspired to continue work on the GPM Jak-23 "Flora", scaled to 1/16.

    Waiting for some skin to work with, I returned to some rather fun ideas of replicating also the jet engine. The original is a Russian copy of the Rolls Royce Derwent, a centrifugal flow engine, which makes it quite ideal for some kind of a fan unit.

    At first I toyed with some sketches of building the fan unit all by card and paper, with a 1,5-3V engine inside. This would be quite feasible, I believe, although the boost wouldn't be much to boast about, which is a pity, even if it is only for show.

    Then, last Sunday at the flea market, I picked up the most ridiculuous hairdryer in the form of a Donald Duck. The important thing about it was that it was of the linear blow-through type, not the older centrifugal flow type. I thought some careful butchery would at least get me a useable fan, the size of which seemed promising.

    The final result turned out to be immensely much better. When I got through the plastic, and had cut away all the resistor wire heat coils, plus the rectifying components, I was left with a very compact motorized fan unit, powered by a Mabuchi motor. (See photos 1 and 2 below.)

    On the off chance I connected a 1,5V battery, and the thing turned around rather nicely. I then tried a small 9V battery of the type you have in smoke warning devices, and the thing really came alive - the airstream was just as powerful as it would have been from the actual hair-dryer!

    Now this was better than I could ever have dreamt about, and I will definitely use the unit as the basis for a jet engine replica, powered by a rechargeable onboard 9V battery.

    Here's my immediate problem - I now have to confess that I do not know how to design or draw even the most basic card-modeling part, a simple cone.

    So I would be immensely grateful if someone, to whom it might perhaps be a comparatively easy job, would help me out with the cone part of the fan unit. The dimensions are given in the drawing in image 3 below.

    The only reward will be to have helped this really powerful little model jet engine to have come alive. I promise to report all progress. And I should say that the fan unit is absolutely perfect in size for a 1/16 scale Derwent jet engine. It really is a fantastic little unit, and I do recommend anyone who feels inspired a visit to the nearest flea market!

    Leif

    PS. I should say that Rob Carleen has already let me have access to his J-33 card model jet engine, made for his upcoming Fiddler's Green P-80 Shooting Star model. Many thanks to Rob for his kindness! You can see the engine, and his P-80 prototype in his gallery, and a preview of his Fiddler's Green model here. I will try to adapt Rob's J-33 painting scheme to my jet engine, although it will unfortunately not be visible in the finished model (I don't fell I'm quite up to the task of making the nose part of the Yak-23 realistically detachable; but I promise that I will at least think about it, since it would be such fun to be able to show off the engine!)
  2. Leif Oh

    Leif Oh Member

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    With the thread on replicating alu skins going so well, I got quite inspired to continue work on the GPM Jak-23 "Flora", scaled to 1/16.

    Waiting for some skin to work with, I returned to some rather fun ideas of replicating also the jet engine. The original is a Russian copy of the Rolls Royce Derwent, a centrifugal flow engine, which makes it quite ideal for some kind of a fan unit.

    At first I toyed with some sketches of building the fan unit all by card and paper, with a 1,5-3V engine inside. This would be quite feasible, I believe, although the boost wouldn't be much to boast about, which is a pity, even if it is only for show.

    Then, last Sunday at the flea market, I picked up the most ridiculuous hairdryer in the form of a Donald Duck. The important thing about it was that it was of the linear blow-through type, not the older centrifugal flow type. I thought some careful butchery would at least get me a useable fan, the size of which seemed promising.

    The final result turned out to be immensely much better. When I got through the plastic, and had cut away all the resistor wire heat coils, plus the rectifying components, I was left with a very compact motorized fan unit, powered by a Mabuchi motor. (See photos 1 and 2 below.)

    On the off chance I connected a 1,5V battery, and the thing turned around rather nicely. I then tried a small 9V battery of the type you have in smoke warning devices, and the thing really came alive - the airstream was just as powerful as it would have been from the actual hair-dryer!

    Now this was better than I could ever have dreamt about, and I will definitely use the unit as the basis for a jet engine replica, powered by a rechargeable onboard 9V battery.

    Here's my immediate problem - I now have to confess that I do not know how to design or draw even the most basic card-modeling part, a simple cone.

    So I would be immensely grateful if someone, to whom it might perhaps be a comparatively easy job, would help me out with the cone part of the fan unit. The dimensions are given in the drawing in image 3 below.

    The only reward will be to have helped this really powerful little model jet engine to have come alive. I promise to report all progress. And I should say that the fan unit is absolutely perfect in size for a 1/16 scale Derwent jet engine. It really is a fantastic little unit, and I do recommend anyone who feels inspired a visit to the nearest flea market!

    Leif

    PS. I should say that Rob Carleen has already let me have access to his J-33 card model jet engine, made for his upcoming Fiddler's Green P-80 Shooting Star model. Many thanks to Rob for his kindness! You can see the engine, and his P-80 prototype in his gallery, and a preview of his Fiddler's Green model here. I will try to adapt Rob's J-33 painting scheme to my jet engine, although it will unfortunately not be visible in the finished model (I don't fell I'm quite up to the task of making the nose part of the Yak-23 realistically detachable; but I promise that I will at least think about it, since it would be such fun to be able to show off the engine!)
  3. cecil_severs

    cecil_severs Member

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    Lief,

    Try here for the latest version of cone software:

    http://www.pulserate.com/

    It's simple and seems to work well.

    Hope this helps.

    Cecil
  4. cecil_severs

    cecil_severs Member

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    Lief,

    Try here for the latest version of cone software:

    http://www.pulserate.com/

    It's simple and seems to work well.

    Hope this helps.

    Cecil
  5. Thomas Pleiner

    Thomas Pleiner Member

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    Leif,
    you may download the un-wrapped cone from here:
    http://www.mtp-studio.de/downloads/cone.zip
    The zip-file contains a Corel 9 file with two versions
    of the unwrapped cone, an Adobe-Illustrator vector
    file and a few jpg's.
    Hopefully this helps . . .

    Best regards
    Thomas Pleiner
  6. Thomas Pleiner

    Thomas Pleiner Member

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    Leif,
    you may download the un-wrapped cone from here:
    http://www.mtp-studio.de/downloads/cone.zip
    The zip-file contains a Corel 9 file with two versions
    of the unwrapped cone, an Adobe-Illustrator vector
    file and a few jpg's.
    Hopefully this helps . . .

    Best regards
    Thomas Pleiner
  7. Leif Oh

    Leif Oh Member

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    Problem solved - many thanks to Thomas Pleiner and Gil Russell, who both came through beautifully! I will enjoy this little part of the build very much.

    Thanks also to the signature "FordCortinaAZ" who came through with data which would have enabled drawing the cone, had all else failed; and to Cecil for the tip on the software (which, unfortunately, is out for me, being on a Mac as I am...).

    Best, Leif

    PS. On closer examination of the files, I discovered that one of them - quite by accident apparently - marks a number of segments divisible by seven, which just happens to coincide with the number of combustion chambers of the Derwent engine. I had neglected to mention this, since I did not know the output of the design software would provide such segments. All the more fortuitous, and I am very glad. Will make the adaptation of Rob's pattern much easier indeed!
  8. Leif Oh

    Leif Oh Member

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    Problem solved - many thanks to Thomas Pleiner and Gil Russell, who both came through beautifully! I will enjoy this little part of the build very much.

    Thanks also to the signature "FordCortinaAZ" who came through with data which would have enabled drawing the cone, had all else failed; and to Cecil for the tip on the software (which, unfortunately, is out for me, being on a Mac as I am...).

    Best, Leif

    PS. On closer examination of the files, I discovered that one of them - quite by accident apparently - marks a number of segments divisible by seven, which just happens to coincide with the number of combustion chambers of the Derwent engine. I had neglected to mention this, since I did not know the output of the design software would provide such segments. All the more fortuitous, and I am very glad. Will make the adaptation of Rob's pattern much easier indeed!
  9. Maurice

    Maurice Member

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    Leif

    Early versions of the Derwent had 10 combustion chambers but the substantial redesign for later versions used 9.
    http://www.gasturbine.pwp.blueyonder.co.uk/derwent.htm
    et seq
    the .mpg is fun for those who haven't heard a Derwent recently, however the complete manual may go into slightly more detail than you need. :D

    Cheers
    Maurice
  10. Maurice

    Maurice Member

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    Leif

    Early versions of the Derwent had 10 combustion chambers but the substantial redesign for later versions used 9.
    http://www.gasturbine.pwp.blueyonder.co.uk/derwent.htm
    et seq
    the .mpg is fun for those who haven't heard a Derwent recently, however the complete manual may go into slightly more detail than you need. :D

    Cheers
    Maurice
  11. Leif Oh

    Leif Oh Member

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    Maurice - yes, of course - nine, not seven! Stupid me. Rob already told me nine. Wishful thinking, I suppose... Back to the drawing board. Before I start, how many combustion chambers would you say the Russian copy, RD-500, has judging from the cut-away drawing below?

    Lovely site on the Derwent, thanks!

    Leif

    (Edited cause I can't differ between seven and nine, even when I intend to make it right. Talk about Tim's "multiplying eye"; see postings below.)
  12. Leif Oh

    Leif Oh Member

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    Maurice - yes, of course - nine, not seven! Stupid me. Rob already told me nine. Wishful thinking, I suppose... Back to the drawing board. Before I start, how many combustion chambers would you say the Russian copy, RD-500, has judging from the cut-away drawing below?

    Lovely site on the Derwent, thanks!

    Leif

    (Edited cause I can't differ between seven and nine, even when I intend to make it right. Talk about Tim's "multiplying eye"; see postings below.)
  13. Maurice

    Maurice Member

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    Leif

    Roughly about the 9 one would expect on a direct copy of a later Derwent. :D

    Cheers
    Maurice
  14. Maurice

    Maurice Member

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    Leif

    Roughly about the 9 one would expect on a direct copy of a later Derwent. :D

    Cheers
    Maurice
  15. Sticky Fingers

    Sticky Fingers Member

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    Now all you need to do is introduce a little butane or propane and light it off. It would be interesting to see just how long it would last :roll:
  16. Sticky Fingers

    Sticky Fingers Member

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    Now all you need to do is introduce a little butane or propane and light it off. It would be interesting to see just how long it would last :roll:
  17. wunwinglow

    wunwinglow Active Member

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    Four of these, and a 1:12 scale 747 or A380 would look cool..... Sound pretty cool too, I shouldn't wonder!

    [​IMG]

    Tim P
  18. wunwinglow

    wunwinglow Active Member

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    Four of these, and a 1:12 scale 747 or A380 would look cool..... Sound pretty cool too, I shouldn't wonder!

    [​IMG]

    Tim P
  19. wunwinglow

    wunwinglow Active Member

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  20. wunwinglow

    wunwinglow Active Member

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