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May 14, 2014, 11:21 AM
Letís eschew obfuscation.
scott swanson's Avatar
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Quote:
Originally Posted by felixx
OK So I printed my plans to build this soonish (just need to get the other two planes in the air when HK gets my components to me. This plane will be my third build! Anyway my question is; will Balsa be OK for a wing spar? Or even Cedar? I know that cedar will be heavier but its only a couple of grams. I was going to cut THROUGH the wing and add the balsa or cedar (or even 3mm ply) between the two pieces of foam in the cut
felixx,

Everyone has fun modifying published plans, but when you do you must realize that you are doing an experiment and the results are unknown. Just changing the CF tube to wood, even if it is as thick as the Depron, probably won't work.

There are some ways to maintain strength while still using a weaker spar material. One is to make the wing cross section (and spar) thicker like a KFm wing. Another is to add struts. Davereap has had success by using a KFm wing with pallet strapping material glued to both sides.

You must fashion some way of making the dihedral joint in the spar (plywood gussets, maybe). If you'll be flying on water, seal your wood so it doesn't soak up water.

On a side note, you may want to fly your first two planes to see what can be learned before getting too far into your third build.

Good luck,
Scott
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May 14, 2014, 04:09 PM
crash expert
Thankyou Scott, this is exactly the response I was after, considered, informative and helpful.
(No sarcasm at all). This forum is amazing!
May 15, 2014, 11:21 AM
Registered User
ringo42's Avatar
Got my parts cut out last night and started on the pontoons. How you you make sure the joint are all waterproof without adding a ton of glue and making it heavy?
May 15, 2014, 12:49 PM
Registered User
I plan to seal all the joints on my plane with water based polyurethane. I figure it should flow into all the gaps nicely
May 15, 2014, 01:02 PM
Registered User
Quote:
Originally Posted by fuzzydog
I plan to seal all the joints on my plane with water based polyurethane. I figure it should flow into all the gaps nicely
I am planning on doing the same... inside and out.
May 15, 2014, 05:02 PM
Registered User
Quote:
Originally Posted by fuzzydog
I plan to seal all the joints on my plane with water based polyurethane. I figure it should flow into all the gaps nicely
Is this the one you are talking about: http://www.gorillatough.com/index.php?page=dries-white

I used it on another model and was planning to use it on the slowboat.
May 15, 2014, 05:21 PM
Registered User
Actually.... I bought some ezekote wbpu and really like how that goes on the foam. I now know that I can get pretty much the same stuff for much less $$ in the Minwax or Varathane brand names but now that I have it, i will use it up.

For sure I will seal all of the foam joints up with a bead of it, and might even just coat the entire outside of the plane as it does give a good measure of ding resistance.
May 15, 2014, 07:37 PM
Registered User
OK, got it. Looks like a good product to seal things up near completion of the build.

As for the glue to fasten the foam together, I plan on using a combination of the Gorilla Glue I posted above and foam safe CA.

What I would really like is something that works like a silicon seal where you can smooth the joint off with a finger and leave a nice smooth joint. Or is that what eze-kote does?

Thanks,
May 15, 2014, 08:03 PM
Registered User
Murman's Avatar
Quote:
Originally Posted by ronaldj
Is this the one you are talking about: http://www.gorillatough.com/index.php?page=dries-white

I used it on another model and was planning to use it on the slowboat.
I used that for pretty much my entire build. It works great, but you have to be careful not to use too much or it will expand too much and look like crap. It dries white, but yellows after exposure to sunlight for a while.
May 15, 2014, 08:11 PM
Registered User
Quote:
Originally Posted by fuzzydog
...and might even just coat the entire outside of the plane as it does give a good measure of ding resistance.
That's a buncha weight. The only ding resistance needed are the wing leading edges, and the underside from nose to step. That can be done with very lightweight clear tape. OK to tape it from the step to the tail too.

As a test, measure up the square inches you want to paint. cut a piece of cardboard to those square inches, weigh it, paint it, and weigh it again. If you add 2 oz of paint to a 15 oz plane that's ~13% which costs speed, flight time, and agility. The clear tape will add only a fraction of an oz to the weight.
May 15, 2014, 08:21 PM
Registered User
Quote:
Originally Posted by ronaldj
What I would really like is something that works like a silicon seal where you can smooth the joint off with a finger and leave a nice smooth joint.
Same as my last post, GG or silicone or whatever all cost a ton of performance. CA is all you need.

To both, you'll never understand the advantage of a truly minimal weight plane, until you fly one that's too heavy, and then build a minimal one. So build it twice, one any way you want to, then another minimal. I can't emphasise enough that weight -is- the devil.

Example, I have a Slow Stick that grew and evolved from 18 ox to 34 oz. It flies great, heavy lifter, aerobatic. Then I found a never-flown used one of craigslist, and I swear it made me feel like a virgin again.
May 16, 2014, 10:20 AM
Registered User
Great info guys, thanks. CA and Gorilla glue is it. The tape sounds like a good idea as well.
May 21, 2014, 09:23 AM
Registered User
ringo42's Avatar
I just noticed the pushrod setup. Those are awfully thin rods. No issues with flexing?
May 21, 2014, 12:27 PM
Registered User
Quote:
Originally Posted by jbarchuk
...

To both, you'll never understand the advantage of a truly minimal weight plane, until you fly one that's too heavy, and then build a minimal one. So build it twice, one any way you want to, then another minimal. I can't emphasise enough that weight -is- the devil...
I understand and agree fully. This particular Slowboat has evolved to be my Glowboat, dedicated for night flying The weight is already blown up with all the leds and wiring so waterproofing and durability are taking precedence over lightweight. I just want something that will fly nicely at night, and with which I can take off and land from water.

When I cut out my foam, I made hardboard templates of all the pieces so that I can now make as many additional planes as I want quite quickly. The glowboat will be nice for flying at night, but for day flying I will want an original slowboat built to lightweight standards, as you recommend.
May 21, 2014, 12:51 PM
Retired CAD guy
birdofplay's Avatar
Well I finally finished my original Slowboat last PM.

I got about half dozen touch and go's around the patch when
my Aileron Servo or my Cheapo Orange Rx went Bonkers
and I now get to start over.

THATS TWO Orange RX's that have given me FITS with intermittent operation.
I bent one of my 9mm Mig-29's with one that had a satellite rx too.

Now HK wants me to believe that Orange is superior to Lemons.

So I ordered some Lemons to find out for myself !

L8r

Bob
Hoosier Cutout Service


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