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Author Topic: Crosby CR-4 NoCal  (Read 1647 times)
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dslusarc
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« Reply #50 on: March 15, 2021, 11:22:57 PM »

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Thanks for pushing me not to give up on this one.  I was pretty disappointed last outing with it, but your pointers made great sense.  Shocked everyone that this planform did fly.  Plus I like being different. Will you be coming to the Spring Fling in May?

Archie Adamisin
Burlington, KY

Yes nocals can be touchy sometimes, especially low wing subjects. So glad to see the transformation into happy flying plane :-) I just had to recover my Crosby as I guess I was skimpy with the spray adhesive and the tissue was falling off. So re did it with white glue and water over the weekend. I am planning on the May contest, have my hotel booked. Will have my Crosby with me. Hopefully a WWII as well.   

Don
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OZPAF
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« Reply #51 on: March 17, 2021, 03:23:27 AM »

That was an interesting trim solution for your Crosby Archie. It seems to me that apart from reducing tip stall - the tip washout in reducing the wing incidence overall has also reduced the AOA with respect to the thrust line and thus leading to a climb further from the stall.

Anyway good luck with it.

John
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AAdamisin
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« Reply #52 on: March 23, 2021, 07:12:02 PM »

That was an interesting trim solution for your Crosby Archie. It seems to me that apart from reducing tip stall - the tip washout in reducing the wing incidence overall has also reduced the AOA with respect to the thrust line and thus leading to a climb further from the stall.

Anyway good luck with it.

John

This model has a really high taper ratio.  This led to tip stall then into power stall.  The lack of decalage then made it hunt and that just helped to induce more madness. 

I am far from expert on this, but with the washout, the stalls were mild and departure from stall was immediate.  The added decalage then added the stability it needed.  Still needs a bit more tail incidence and then very careful attention to winding technique.  Bunching cost me a chance in a flyoff.  I think there is room for more in the prop.as I only used a 7 x 8.4 x 1.125 on it.  I have a 7 x 9 and a 7 x 10.5 that could stretch the duration if the thrust is enough to pull this bird around.

Archie Adamisin
Burlington, KY
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Archie Adamisin
Burlington, KY
dslusarc
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« Reply #53 on: March 23, 2021, 08:15:39 PM »

Best way to solve rubber bunching on indoor nocals is adding spacing on the rear hook and thrust bearing.
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AAdamisin
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« Reply #54 on: March 30, 2021, 07:45:01 PM »

Best way to solve rubber bunching on indoor nocals is adding spacing on the rear hook and thrust bearing.

Good tip.  I will try that. 

Thanks!!

Archie Adamisin
Burlington, KY
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Archie Adamisin
Burlington, KY
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