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Dec 23, 2017, 04:06 PM
AndyKunz's Avatar
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The wing tips on this plane are not like the original Kadet tips, which were rounded down from the top with a generally-flat bottom. Instead they are like the Kadet Sr tips - flap on the bottom, angled upwards to the top of the airfoil. I couldn't see myself carving and sanding those huge foam blocks. Michael's suggestion to go this way was spot-on.

So here's how I make them. I made eight right triangles of various sizes, corresponding to where I felt they would need to be bracing the tip (TLAR engineering at its finest ). I glued them to the tip rib. Next, I sanded the bottom of the tip cap strip to match the angle, and then glued an oversized (top to bottom) rib on.

While that cures, I'll be off getting started on the next plane.

Andy
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Dec 24, 2017, 05:33 PM
AndyKunz's Avatar
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The top tip sheeting is 1/16" balsa pieced together to make a 20" wide sheet 2 1/2" long. I used slightly harder wood for the TE area, and softer for the rest.

The next step is to remove the excess of the tip diagonal portion. I started with a #26 and #11 blade to carve it down, then masked the balsa and finished the shaping with the sanding block.

In order to support the top tip sheeting, I removed about 1/16" of the LE sheeting, using blue tape as a straight edge. After that, it was just a matter of trimming the top tip sheet so extend like a cap strip over the open bay area, while being snug against the LE and TE sheet. I used tape to hold everything in place and set it aside until tomorrow.

And speaking of tomorrow - it's Christmas. Remember why we celebrate; it's not the toys with exchange. It's the Perfect Gift of grace, one that none of us deserves but that all are freely offered: Salvation through Jesus Christ.

Andy
Dec 24, 2017, 05:36 PM
Wanted for breaking Ohm's Law
Dennis Sumner's Avatar
Merry Christmas to you and your family!
Latest blog entry: RC Throw Gauge
Dec 27, 2017, 10:25 AM
AndyKunz's Avatar
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Thanks, Dennis, it was great! I hope yours was as good as ours.

Ian and I were working in the shop most of the afternoon. He posted his updates on his UMX Tri-Star thread, but my work was just sanding. Got some more of that to do and then I hand it off for covering. The rest of the time I spent working on tweaks of the Neo 280 plans and cut files, getting it ready for production. Hopefully by New Years I have it out of here.

I need to see more Pharoah pix! You're starving us!

Andy
Dec 27, 2017, 12:45 PM
Registered User
This is going to be a really nice airplane, and definitely a floater. However I'm not so sure about the Enya 90. Generally the relation between size and power is roughly cubic, so if you go 1.5x, you'd expect to need 1.5x1.5x1.5 = 3.4 times the power. Working backwards, your 90 is equivalent to about a 26 four stroke on a Sr. Kadet.

Now, I'm not saying it will necessarily be that under-powered, since you're probably building pretty light. There is a 120 inch Comet Clipper someone has powered with a Saito 56. It weighs 7 1/2 lbs. But I'd just keep in mind, you might really want a 120 four stroke on there.

Nice work!
Jim
Dec 27, 2017, 01:46 PM
AndyKunz's Avatar
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Thanks, Jim. And thanks for the feedback on power.

We* went through the power back before starting. I expect the .90 to be plenty for the mission - it's not going to be flown like the average sport plane, so we don't need insane power.

This is an 80" plane. Compare it to the Kadet Senior at 78" - Sig says .29 to .40 2-stroke, and lots of folks fly them with a .60 and have oodles of power. I'm pretty sure a .90 4-stroke will work just fine.

Andy

*We - the "we" here includes people who were part of the process at the time were on the Hangar 9 and Evolution engine development teams. I'm not personally into big models, but they are and I trust their judgement.
Dec 27, 2017, 02:06 PM
Registered User
My dad built a Kadet Sr., powered it with a Supertigre G40. Plenty of power, it'll fly at about 1/4 throttle..
Dec 27, 2017, 02:45 PM
Registered User
Oh, sorry, Andy, I saw 150% and thought 150% of a Sr. Kadet, which would be close to 120 inch.

You're absolutely right, on an 80 inch Kadet it will be plenty.

Jim
Dec 27, 2017, 02:47 PM
AndyKunz's Avatar
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Oh, that would be a MONSTER airplane!!! Candy-STORE bomber!

Andy
Dec 28, 2017, 10:27 AM
ARFs Are Me
TomCrump's Avatar
Quote:
Originally Posted by buzzard bait
Oh, sorry, Andy, I saw 150% and thought 150% of a Sr. Kadet, which would be close to 120 inch.

You're absolutely right, on an 80 inch Kadet it will be plenty.

Jim
I thought so, too.
Jan 03, 2018, 10:43 PM
AndyKunz's Avatar
Thread OP
I got a bit more done tonight on the Kadet. The itch to have it in somebody else's shop is pretty strong

I shaped the LE, starting with a block plane, then a 3' sanding block, and finally a flexible block. As expected, the LE needed to be replaced so I cut out the too-thin sheeting and substituted a solid block. Tomorrow (morning, I hope!) I'll sand this to match the wing, then take it to work and let Michael work his magic on it.

Next I put one wing on and marked/drilled a hole through the fuselage into the root rib. Then I pulled that wing off and put the other on, and drilled through from the other direction. This gave me pilot holes that I drilled out and tapped for 4-40.

Andy
Jan 04, 2018, 07:49 AM
ARFs Are Me
TomCrump's Avatar
I was wonder what size of wing retention bolt would be used. I'm a little surprised that you tapped the wood, instead of using blind nuts.
Jan 04, 2018, 09:14 AM
AndyKunz's Avatar
Thread OP
There's not a lot of stress pulling wings off in flight. I used 1/4-20. It's the same size that was on my son's 60-size Extra which can roll like a prop.

Andy
Jan 04, 2018, 09:26 AM
ARFs Are Me
TomCrump's Avatar
Quote:
Originally Posted by AndyKunz
There's not a lot of stress pulling wings off in flight. I used 1/4-20. It's the same size that was on my son's 60-size Extra which can roll like a prop.

Andy
I was just curious, that's all.

Tapping can strip out, but blind nuts can fall out, inside the wing. Both methods have their attributes and drawbacks.
Jan 04, 2018, 09:34 AM
AndyKunz's Avatar
Thread OP
When I use blind nuts, depending on how big, I will either epoxy them in or put a plate behind them and epoxy that plate in.

With tapped wood, it gets hardened with CA (I left that for Michael since CA makes me sick). If it gets stripped, I can put in a threaded insert or drill it out and insert a dowel and re-tap it.

Andy


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