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Old Feb 04, 2013, 02:37 PM
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New York
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Great solution, Harm. Looks like I'm going with your approach! Eager to hear your flight report.

Steve
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Old Feb 08, 2013, 06:55 PM
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Joined Jul 2009
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Lower spoiler location

Hi KA8 guys, I need some help. Since I got the wing fix cf tubes AllenK suggested before the replacement wings came out, and my replacements aren't as nice cosmetically as my originals, I'm in the midle of doing the AllanK fix to the originals. I plan to install 440 electric spoilers top and bottom. The top spoiler box has a space of about 1 1/4" between it and the back of the d-box & spar webs. Question: Would it pose any problems if I locate the bottom ones right behind the d-box instead of leaving the space? It would be easier and maybe stronger than the top one with the space. If it is a toss-up, I'll mount them behind the spar, and post pictures of the upgrades. Oh, one more thing--is it worth the effort and weight (mine is really heavy with all the mods) to intall the lower ones, or just use the top ones? I've got ample landing space. Thanks, Bob.
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Last edited by flyingfever; Feb 08, 2013 at 07:17 PM. Reason: add info
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Old Feb 08, 2013, 09:52 PM
Vintage wood is the best!
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In a house
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I have just the top spoilers and mine stops just fine.
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Old Feb 13, 2013, 10:13 AM
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Iceland
Joined Dec 2004
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So what's the smallest plane you've used to tow the K8 up so far?

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Old Feb 14, 2013, 07:47 AM
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100cc 3 meter Pawnee but you don't need that much.
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Old Feb 14, 2013, 02:15 PM
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Holland
Joined Jan 2004
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I have a possible canditate for trying this, the MPX FunCub

http://www.youtube.com/watch?feature...&v=B7TWg5yQ6NI
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Old Feb 14, 2013, 04:01 PM
Electric Airplane Junkie
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San Mateo, Ca , USA
Joined Jun 2000
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Only in very cold weather where the air is really dense.

Brian, an EAJ
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Old Feb 16, 2013, 03:55 AM
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Brisbane Australia
Joined Oct 2000
125 Posts
Quote:
Question: Would it pose any problems if I locate the bottom ones right behind the d-box instead of leaving the space? It would be easier and maybe stronger than the top one with the space. If it is a toss-up, I'll mount them behind the spar, and post pictures of the upgrades.
I did mine this way for the lower surface (after building mechanical brakes, I went with off the shelf). Simple and strong box once glued in.


The 2nd box to be fitted to the other wing is shown.


The Alan mod but the carbon tube and shipping would have cost as much as I got the kit for! I'm using 2 carbon wing joiner tubes per side that cost wayyy less. The tubes are just sitting there in the image and will be bonded to each rib with plates and be glued to existing joiners by a method I've yet to devise. But it will happen.


The tubes slide into each other, firm fit and will be glued and kevlar thread wrapped around join.
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Old Feb 16, 2013, 02:24 PM
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Joined Jul 2009
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wing mods

B- Thanks for the reply and pictures. Looks the same as my fix. By removing some rib matrial behind the end of the joiner tube, the cf tube nestled up against the inner end of the front joner. Regarding the bottom spoiler, I was concerned, since the rib doublers (tube mounting plates) transfer the forces to the spars, the cutout for the bottom spoiler box would reduce the strength. If the spar tube is well anchored to the joiner tubes, it'll probably be fine. Also, the inner wing sheeting covering the 1st 2 bays and joiner tubes was quite easily removed, exposing the 2 inner bays, allowing adequate reinforcent and joining of the cf spar tube and cardboard joiner tubes and webs. The sheeting seemed glued solid at first, but due to spotty glue application, I scored the sheeting joints at the spars, reached in underneath the sheeting, and popped it free in 1 piece. It took a little prying, but well worth it for access to inner tubes and webs. I intend to glass the cb tube to the front joiner tube & spar. Is it necessary to add spar web doublers to cover the > cutouts on the rear spar? I'll get some pictures posted soon. Thaks again to all. Bob.
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Old Feb 16, 2013, 05:08 PM
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Brisbane Australia
Joined Oct 2000
125 Posts
If the new spar tube ended at the spoiler cut out I'd be worried about the load transferred through the ribs in that area, but it carries through to the end. The ribs are ply and flimsy and are more like shape holders for the covering and spacers between the D box and rear spar than structural elements, the box adds rigidity in that area so I'm not as concerned about that spot as I am about the rest of the wing. I am going to add shear webs to the rear spar (if it can be called that) as I have access and I don't like the look of it. e.g. Look at the first image, I think they missed one behind the spoiler box?
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Old Feb 16, 2013, 09:32 PM
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New York
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Bananaman, how much overlap between the nesting carbon tubes?

TIA,

Steve
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Old Feb 17, 2013, 03:42 PM
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Brisbane Australia
Joined Oct 2000
125 Posts
I have enough material to do 18" but I'll overlap by 8". The tubes are a very good fit. No slop.
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Old Feb 17, 2013, 08:13 PM
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United States, WA, Tumwater
Joined May 2010
258 Posts
We've towed behind a 1/3 scale cub with a Zenoah 80. Long, scale tow. Did see the cub yanked out of the air by one of these planes on maiden, But our tug pilot just righted things and continued on like nothing happened. Our regular tow plane is 1/3 Pawnee with a 3w 106

Mark
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Old Feb 18, 2013, 08:57 PM
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Iceland
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Cheers, our normal tug is also a Zenoah 80 powered 1/3 Cub so good to know it's doable.
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Old Mar 05, 2013, 03:28 PM
Vintage wood is the best!
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In a house
Joined Sep 2002
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Alright.....I have my new panels all done....swapped over the spoilers and wiring harnesses.....ready for Cumberland in three weeks!
The new wings also did not come with the reg letters on the bottom.....I just put large 4 - 10"x10" diamonds of red on both wing bottoms to help with viability in the air....its not like these are scale anyways!
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