Damn nutplates!

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Postby Shannon » Mon May 09, 2005 11:54 am

Actually these plates are not as "monsterous" as what was supplied in the JPX engine install wing upgrade kit (see pic). There are several ways one could do this.
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Postby Shannon » Mon May 09, 2005 11:57 am

JPX engine install upgrade kit. Reinforcement plates and " Mount Pads".
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Postby lazflyn » Wed May 11, 2005 6:03 am

Perfect Shannon. It is all clear now.

The final (hopefully) questions: Are the G412 and F423, 6061 T-6? What guage?

Thanks,

MarkDJ.
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Postby Shannon » Wed May 11, 2005 11:23 am

Hi Mark,

I do not have the exact specs and diemensions for the materials that were shipped with the JPX install wing upgrade kits (motor mounts, box section, ect). I also do not have the exact thicknesses for 412's and 423 mount pads. What I'd do is get with George as he has installed a factory type set-up. My mounts (plates) however were custom fitted for a doubled D-cell skin wing so they are a little different than what you will need with standard skin.

Shannon
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Postby JPXman » Mon Jun 20, 2005 2:11 am

just an update: my lazair is ready for test flight finally, after almost 4 years of trial, error, rebuild, recover, podification and modification. we did a weight and balance today, a true one too.

we took a come-along and a 150lb fish scale and set out to weigh the airplane. We came up with the following numbers:

- aircraft weight with:
-no engines, EC, parachute, instrument pod, battery, gallon of gas
= 270 pounds!

- weight of one JPX assembly with nacelle, prop, exhaust
= 48 pounds! (same config yields 80 lbs static thrust on test stand)

for an empty weight of 365 pounds!

so, she's not a light bird, but she's got the elite modifications so it should be fine. Then, I climbed in with my limber weight of 270 pounds and 6'7" frame and we hung it at 15" aft of leading edge and the tail came up before the mains - good news!

then we hung it from 12" aft of the leading edge and the mains came up first - perfect.

So, the CofG with me and the plane and a gallon of gas is somewhere between 12 and 15" just like the book says it should. even though i am way over "quoted" gross weight, i take comfort knowing i'm at least balanced ;)

test flight soon when i have more days off. thanks for all the help myles!
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Postby Guest » Mon Jun 20, 2005 5:54 pm

Tyler re-check the total weight figure, 365lbs empty seems a tad high ??? Shouldn't your plane weigh about 260-270 with the engines but without the full fairing ???
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Postby JPXman » Mon Jun 20, 2005 6:34 pm

nope that's the right number. it makes sense when you break it all down:

- EC = 25 pounds
- instrument pod - 8 pounds
- parachute - 30 pounds
- battery and wiring - 5 pounds
- jpx assemblys weigh at least 15 pounds more than a rotax, adding 30 pounds

so right there that's over 100 pounds of extras. i have a lt of extra aluminum in my frame to to beef it up for my large girth and bigger engines too. so it all adds up. but boy does it look sweet ;) now we have to see if it flies...
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Postby Guest » Tue Jun 21, 2005 7:34 am

Lazair SS EC with electric start KFM's was listed at 343lbs.
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Postby JPXman » Tue Jun 21, 2005 4:10 pm

well i feel a lot better about my bird knowing that, thanks guest!

I'm only above that number by my parachute when you consider the JPX's are probably slightly lighter than the KFMs. yeehaw!

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Postby Guest » Fri Jul 01, 2005 11:19 pm

KFM's were 62lbs each.
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