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Aug 08, 2019, 07:06 PM
flyin' fool
goldguy's Avatar
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An improvement or just different?

It seems that the LE sweep and wing loading effects the most changes. I've tried many different airframes made up of triangles and rectangles of all shapes and sizes, each resulting in slight differences.

The little R's LE is a total of 90 degrees compared to 66 for the PL. It ***seems to be less effected by the wind and rolls/spins faster.

*** could just be my imagination
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Aug 21, 2019, 04:15 PM
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Quote:
Originally Posted by Aer0naught
Awesome! It would be great to see a comparison between the Lark and the StingRay. I had been looking at building a StingRay, but I only had 2mm Depron and a little bit of 0.8mm CF on hand at the time. The Lark actually worked out to be simpler IMO, with just a spanwise CF rod and foam spine as reinforcement. The only part on the plane that hasn't quite held up is the motor mount, since dorking it in tends to rip the gearbox out of the foam. A little bit of white Gorilla glue solves everything though!

Once I crash this one enough, I will probably build a Lil' Ripper with the same span. Goldguy says it's an improvement over this design, so I gotta try it!
I have a box of 3mm sheet foam from Hobby King and made my Micro Stingray out of that. I double up the front half, effectively creating a KFm-2 airfoil. The Mini and Micro Stingrays are just slabs but I used the plan for the full size Stingray to create the KFm section. The pic is of my Mini that I used as a template. The UMX brick and 3-blade prop are from a T-28. In theory, I'll find out how (or perhaps IF) it flies this weekend. The foam is a bit bowed so, on my first attempt, that gave me a fair bit of natural dihedral. Unfortunately, I realized late in the process I had screwed something up so I had to rip it apart and start over. On the second one, I flipped the KFm section so that it would mostly cancel out the bow in the main wing section. The result is just a TINY bit of dihedral bow so it should fly reasonably well, if it isn't too heavy. Once I get it balanced and trimmed, I should be able to fly it in my yard and perhaps impress the neighborhood youngsters.
Aug 22, 2019, 01:07 PM
flyin' fool
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Lookin' good …………..
Aug 22, 2019, 08:11 PM
Registered User
Markran's Avatar
Quote:
Originally Posted by kdc914
I have a box of 3mm sheet foam from Hobby King and made my Micro Stingray out of that. I double up the front half, effectively creating a KFm-2 airfoil. The Mini and Micro Stingrays are just slabs but I used the plan for the full size Stingray to create the KFm section. The pic is of my Mini that I used as a template. The UMX brick and 3-blade prop are from a T-28. In theory, I'll find out how (or perhaps IF) it flies this weekend. The foam is a bit bowed so, on my first attempt, that gave me a fair bit of natural dihedral. Unfortunately, I realized late in the process I had screwed something up so I had to rip it apart and start over. On the second one, I flipped the KFm section so that it would mostly cancel out the bow in the main wing section. The result is just a TINY bit of dihedral bow so it should fly reasonably well, if it isn't too heavy. Once I get it balanced and trimmed, I should be able to fly it in my yard and perhaps impress the neighborhood youngsters.

Seeing your mention of the Micro Stingray reminded me I have one somewhere. I went looking for it and found it had slipped down behind some other planes. It's so tiny I couldn't see it when browsing the hanger. Thanks for the reminder. I'm going to go fly it.


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