Heinkel Lerche

Discussion in 'Aircraft & Aviation' started by eric_son, Feb 18, 2008.

  1. eric_son

    eric_son Member

    I got the Heinkel Lerche (Lark) kit from the Hobby Factory. It's a 1:48 scale kit designed by Roman Vasyliev for Kampfflieger.

    The kit comes in 4 pages:
    • Page 1 : Title page and aircraft description
    • Pages 2-3 : Parts
    • Page 4 : Assembly diagram

    From the looks of the parts and the assembly diagram, there aren't any parts nor instructions for making moving propellers. I hate models with fixed propellers! It just doesn't feel right. Fortunately, the model seems to have provisions for making the propellers rotate. For one thing, each propeller has its own separate section in the fuselage. Plus, the formers in the propeller segments have but a small hole in the center -- hints on where to put the spinner shaft.
    Hence, I decided to make some additional mods to have spinning propellers.

    I start by pre-assembling the fuselage segments that are connected to the propellers to help me figure out my game plan. After some dry-fittings, I noticed that the edges of the propeller fuselage segments are too rough and won't spin freely. So, I decided to glue a sheet of wax paper to the spinner segments.

    Here's a picture of the front part of the fuselage with the propeller shaft already affixed.

    With all the parts assembled, all that needs to be done is to plug the spinner shaft so that it stays put. This will ensure that only the propeller sections will rotate while the front and rear section of the fuselage stays fixed and aligned to each other.

    After the glue set, the modification seems to work. Both propeller segments of the fuselage rotate with very little resistance. But when I put the model in front of a wind source (hair dryer :D) only the front propeller spins.... the rear one, which should counter-rotate, stays put. :(

    I guess that's about it for now... so sleepy.
  2. That's a really odd looking airplane. I can't wait to see it done. Nice neat build so far. Interesting technique for getting the props to spin freely. If you turn the model around in front of the fan, does the previously static prop spin (and not the "new rear one)?
  3. I'm looking forward to this build, Kampflieger has a nice line of german X-planes, This one is on my to-do list.., Sofar, looking good!
    Cheers, Billy
  4. eric_son

    eric_son Member

    Yes. If turn the model around so that the rear props become the "front", it spins freely. But still, the props behind it won't spin. My guess is the front spinning props somehow breaks up the incoming wind current, and prevents the rear props from getting enough wind to spin properly. (Just my guess... hehehe... I know squat about wind dynamics.:oops:)

    Perhaps when I assemble the wing/ducts around the propellers, I'll get better results.
  5. DHL

    DHL Member

    Weird plane,and nice build eric_son !:thumb:
  6. Lex

    Lex Dollmaker

    Another of the Nazi's desperate attempts to win the war... Nice work so far!
  7. eric_son

    eric_son Member

    Yep, you got that right. Like the Me-163 Komet, the Lerche was meant to be a point defense fighter that could shoot up to the skies to engage the B-17 bombers. It was meant to be armed with a pair of Mk108 30mm cannons.
    But unlike the Komet, the Lerche never got beyond the drawing board stage. There are two other similar VTOL type crafts that never got beyond the design stage -- the Focke-Wulf Triebflugel and the Heinkel Wespe.

    After the war, the US also made an attempt for a similar aircraft. It was called the Convair XFY-1 Pogo. Though the Pogo flew, it turned out that the concept was not really practical and they killed the project not long after.

    Anyway, a little progress:

    I finished making the segments that make up the rest of the fuselage.

    The finished fuselage.
  8. Darwin

    Darwin Member

    Your guess on the wind dynamics is correct, but not all of the story. The forward propellor decreases the wind velocity, so the air has less energy to impart to the rear propellor. That is one of the factors as to why wind farms require so freakin much land area to be effective. Also, the wind will force the forward propellor against the rear propellor, which in turn forces the rear propellor against the after section of the fuselage. As you mentioned, the plane between the segments is acting like a friction brake (perhaps a clutch plate would be better analogy). In short, the forward propellor has no contact between the forward fuselage section and the propellor, but the after one is making contact on both the forward and aft faces, so will have twice the friction-creating area of the forward prop. The poor little bugger doesn't have a chance in the spin department.
  9. Nothing

    Nothing Longtime Member

    looks great! im off to find this model for myself. i love the german x-planes!
  10. eric_son

    eric_son Member

    My next step was to work on the propeller ducts.
    Just by looking at the 7-sided wing former.

    After 3 hours of cutting.... I finally finished assembling the skeleton of the propeller duct.

    Very tedious! For those of you who plan to make this model, make sure you use very VERY strong card stock as the base for the duct formers. The parts are too small and narrow, making them prone to bending. Once they bend... just even a little... they become soft. It took me an hour or so to finally come up with what looks like the picture above. :mrgreen: I know it's not pretty... but it should work.

    I worked on applying the skin of the duct the day after. Wrapping the skin was a lot more tedious than assembling the skeleton. Assembling the skeleton stressed out the formers enough to soften them. I tried to stiffen them up by applying CA to the edges.. they helped a bit...

    Anyway, after half a day's work, I finally finished the propeller duct!
    (Looks more like a NAZI hot tub. :twisted:)

    I'd like to continue working on this...but I have a children's party to attend. :sad:
  11. Lex

    Lex Dollmaker

    That duct looks hard enough... But yours looks very clean! Good job!
  12. Nothing

    Nothing Longtime Member

    very nice. im glad youre posting this now ill know what to expect. keep it up!
  13. eric_son

    eric_son Member

    With the propeller duct done, I started working on the 'fins' where the duct will be attached.

    The fins didn't come with any formers. The fuselage also didn't have any anchor points for the fins. The only guide provided was the 'drawing' of the shape of the fin's contact area with the fuselage. To ensure that I get the correct shape, I glued a mini-tab to act as a makeshift former and anchor.

    With all three fins attached, I could dry-fit the duct. Looks weird...but nice! :)

    Unfortunately for me... the model relies on exact precision. The sins I've committed when assembling the duct are starting to get back at me! wall1
    At some points in the duct, the tip of the propellers get snagged. I already tried to massage/muscle the parts of the duct where the propeller gets snagged. Unfortunately, the massaging didn't work. Oh well.
    I guess I'll just complete this model, then make a wingman for it in the future -- taking care to remember the hard lesson I learned from assembling the duct.
  14. BARX2

    BARX2 Member

    Don't blame yourself too much. It could be the tolerances were too close or the model wasn't designed perfectly. I think the inside of the duct was supposed to have more of a curve in the the "original".
  15. The real thing was never build, so you can use some "artistic freedom" to make it work,( that's what Kampflieger probably used when he designed the model) it still is a great build..
    Cheers, Billyaussie
  16. eric_son

    eric_son Member

    Almost done!

    I'm almost done! I spent this build session on making the doodads such as the air intakes and the guns.

    Here are the parts that comprise the air intakes. Very small. In fact, I dropped on of the parts on the beige floor, white side down! It took a while to find it.

    Here's one of the intakes attached. Note that the rear intake is slightly different from the front intake.

    MK108 30MM gun parts.

    Here's a picture of the Lerche so far. The only thing left to do is to complete the tailfins and landing gear assembly. Then I'll be done and ready to work on another model :)
  17. eric_son

    eric_son Member

    All Done!!!!

    I got a bit sidetracked with the assembly because History Channel started showing episodes that featured the Tiger Tank and other episodes that included the Schwalbe. They may be re-runs..but they're too good to miss out on. Heheheh... Now back to work.

    It took a while to assemble the three landing gears. But fortunately, no problems encountered.

    The tail fins also didn't come with formers/spars. I don't know if they were meant to be assembled flat. But I didn't. Instead, I plugged the base of the fin with a rice grain sized piece of cardboard just to give it some volume.

    After waiting for the glue dry, I finally propped the model up, and said to myself, ALL DONE!

    Some posterity shots:




    All in all, it was a very pleasant model to make. Good design. Excellent fit. :thumb:

    As for the duct, had I been more careful in 'skinning' the duct formers, I'd have been able to come up with a more uniformly shaped duct. This would have allowed the propellers to spin.
  18. 72BMWR75/5

    72BMWR75/5 Member

    Very cool. That thing is crazy looking.
  19. archangel1

    archangel1 Member

    Nice job! :thumb: I've had it sitting in my 'Downloads To Do' folder for a couple of weeks now. At least I have an idea of what to expect when I start mine.
    Did you know you can actually fly the beast in the Il-2 Sturmovik 1946 flight simulator, along with several other Allied/Axis 'Black Projects'? It looks amazing in some of the available videos but I must admit I haven't really tried it. I'm still trying to get the hang of the 'regular' fighters!

    Mike :wave:

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