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Author Topic: The sub 400mg EZB plunge!  (Read 12661 times)
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Olbill
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« Reply #50 on: January 21, 2013, 12:11:24 AM »

I don't like wood glue for my F1L blades. The last couple I made I just used tiny spots of thinned Duco. When I had to redo them to replace the spars, it was easy to get them off the old spars with acetone. Of course my models are Mack trucks compared to EZBs this light.
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ykleetx
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« Reply #51 on: January 21, 2013, 01:07:53 AM »

I don't dilute wood glue because it's hard to pick up a *teeny* drop when the glue is sopping wet.  Wood glue in its original viscosity is easy to pick up, in very small amounts, with end of a 007 or 008" music wire.  A big blob of diluted glue is the last thing you want -- it's going to be heavy.

Applying a small drop of glue takes work, because you have to place it exactly where the wood is touching -- and no more.  You might want to practice a little before gluing down the real prop. 

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albisko
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« Reply #52 on: January 22, 2013, 03:45:48 AM »

hi,
my first attempt for EZB light prop.
blade 0,2mm C-grain
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Re: The sub 400mg EZB plunge!
Re: The sub 400mg EZB plunge!
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ykleetx
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« Reply #53 on: January 22, 2013, 10:23:27 PM »

Those props are very nicely done.  Show us photos of your EZB, too.
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dslusarc
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« Reply #54 on: January 22, 2013, 11:44:00 PM »

I am finding these super light EZB props a pain to work with. I have one blade on and drying. I had to thin the wood glue a little mainly because it was getting a skin on it in a matter of ~60 seconds so had to thin it so I could apply it. I will have blade #2 ready to put on tomorrow. These props are taking way too much time to make. I think I am going to start on my F1L structure and work on these props a little bite at a time due to the long delays needed between steps. These EZB props are not like the old days when I would bake them on a form in the over then have the blades glued on the spar and finished within 30 minutes. Hope these are worth the effort going into them! EZB was so much easier when a "light" one was 500-600 mg!
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dslusarc
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« Reply #55 on: January 22, 2013, 11:51:30 PM »

I don't like wood glue for my F1L blades. The last couple I made I just used tiny spots of thinned Duco. When I had to redo them to replace the spars, it was easy to get them off the old spars with acetone. Of course my models are Mack trucks compared to EZBs this light.

Bill,

I normally use Duco for props as well but I do know from my past experience trying when using this thin .005" thick wood the blades would twist or distort as it dried. So I would add plasticizer to the glue to stop that but then I had to double glue the joints as the pasticizer slowed the dry time so much that glue soaked into the spar wood on the first application. So maybe the wood glue will work OK for me. I think I recall Jerry Nolin using white glue on his "Serendipity" EZB props.   
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dslusarc
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« Reply #56 on: January 23, 2013, 12:54:56 AM »

Well I was going to wait until tomorrow but the first blade looked so good after I took it off the block that I decided to get the second one on before heading to bed. This time I again used the thinned wood glue but did glue dots about 3/8" apart down the spar then put the blade on. The other one I did the tip, root and middle, then went back and added glue in between after it dried. This is all locations at once since I have more work time on the thinned glue. Will weigh it tomorrow.

Don
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ykleetx
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« Reply #57 on: January 23, 2013, 02:04:12 AM »

No complaining allowed when you're going down to 250 mg for the model.  This is not an easy to build 350 mg EZB !

In the end, I think you'll be happy that you went the extra length to minimize glue usage on the prop.
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dslusarc
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« Reply #58 on: January 23, 2013, 07:18:17 AM »

Just took the prop off the block and weighed it. I get 74mg. Not too bad since these blades were about 50mg for the pair. The next one should be a little lighter since they are from lighter blade material. So my weight projection is:

wing: 65mg
stab: 22mg
boom w/fin: 22mg
stick: 73mg
prop: 74mg
Total= 256mg plus wing post and tissue tube weight needs to be added.

Don
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albisko
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« Reply #59 on: January 23, 2013, 09:52:50 AM »

Those props are very nicely done.  Show us photos of your EZB, too.

the rest of the model is under construction
Smiley
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ykleetx
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« Reply #60 on: January 23, 2013, 10:56:52 AM »


wing: 65mg
stab: 22mg
boom w/fin: 22mg
stick: 73mg
prop: 74mg
Total= 256mg plus wing post and tissue tube weight needs to be added.

Don

Well done.  Welcome to the 250 mg EZB club !

When will you get a chance to fly it?  Perhaps some test flights in the living room can be made.

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dslusarc
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« Reply #61 on: January 24, 2013, 12:44:04 AM »

I should be able to test fly Tuesday next week. I ran the weights and numbers through the spreadsheet and I get a CG of about .07" forward of the trailing edge (about 97%) which required a short nose length of only about .5". I hope the prop does not get caught under the wing.   

Don
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ykleetx
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« Reply #62 on: January 24, 2013, 01:35:07 AM »

FYI -- I have my nose at 1", CG .27" in front of TE, and 17% SSM. 
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ykleetx
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« Reply #63 on: January 24, 2013, 01:49:15 AM »

I think a little extra SSM is good for a flexible model.

Also, I remember that I have had the 65 mg prop tuck under the wing  a couple of times: once on a 330 mg model and another on the ultra light one.  Both have the nose at 1".
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albisko
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« Reply #64 on: January 24, 2013, 03:48:20 AM »

Blades after shaping and cutting.
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Wout Moerman
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« Reply #65 on: January 24, 2013, 06:04:28 AM »

I love the colour of the blades. Is it just the ink you used to draw the outline?
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albisko
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« Reply #66 on: January 24, 2013, 06:40:57 AM »

I love the colour of the blades. Is it just the ink you used to draw the outline?

I use food colors dissolved in water.
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dslusarc
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« Reply #67 on: January 29, 2013, 01:20:11 AM »

Spent today rolling some tissue tubes. I rolled some .032", .039" and .047". I plan on either using the .032 or .039 for the EZB. I also have the tail booms glued to the bodies now so just need to get the tubes and posts on. I laid out the model to see how it is going to look, see photo below. Wont be able to test fly tomorrow though, so will have to shoot for next Tuesday evening.

Don
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ykleetx
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« Reply #68 on: January 29, 2013, 10:49:14 PM »

I originally intended to save weight by not using wing posts nor tissue tubes.  I ended up using very short wing posts, and only one tissue tube for the front wing post.  I glue the rear wing post in place at the flying site and remove it to put the wing back in the box.  I will put a second tube on in the near future. The tube ID is .047".
« Last Edit: January 29, 2013, 11:00:01 PM by ykleetx » Logged
ykleetx
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« Reply #69 on: January 29, 2013, 10:54:59 PM »

My model at Lakehurst:

https://picasaweb.google.com/108052131825905862674/Indoor?authkey=Gv1sRgCKHGy8us3vTxJw#5795630470249402450

At home with a smaller, lighter prop:

https://picasaweb.google.com/108052131825905862674/Indoor?authkey=Gv1sRgCKHGy8us3vTxJw#5767286610287325698
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dslusarc
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« Reply #70 on: February 04, 2013, 01:12:18 AM »

Well it is ~260-265mg, hard to tell the scale bounces around with the model sitting on the scale. I test flew it in the house and I am amazed these tiny wing spars hold up so well. I used a 8" loop weighing 235mg with 800 turns and it was climbing and I was able to see how it handled bumping my ceiling. Seems as stable as my other EZBs. I am not sure how much opposite wash it will need. Right now the wing has none. But need to test fly in the gym to see how it handles once I add more torque. Usually I need about 3/32" opposite wash in an EZB.   
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ykleetx
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« Reply #71 on: February 04, 2013, 02:01:37 AM »

It looks really nice.  Total flying weight is only around ~500 mg, so the wing can be substantially weaker than a 500 mg EZB with a flying weight of 1 g.

I think you will really enjoy flying it.
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Wout Moerman
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« Reply #72 on: February 04, 2013, 04:52:28 AM »

What do you mean with "opposite wash in an EZB"? Is that wash out?
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dslusarc
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« Reply #73 on: February 04, 2013, 07:19:04 AM »

Opposite wash means the wash in is in the outer wing instead of the inner wing (when at rest). The reason it is done is because the motor stick twists when the motor is attached and causes the outerwing to have washout. Too much washout can make the wing tuck in at launch. By adding opposite wash in, when the motor is attached, the outer wing goes flat (the wash in in disappears) and wash in appears on the inner wing from the motorstick twist. So opposite wash means wash in on the opposite wing.

Don    
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ykleetx
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« Reply #74 on: February 04, 2013, 12:47:13 PM »

Don,

My guess is that you won't need much "opposite wash", if any.   Your motor stick is stout for this size of model.  My model has a very small amount of opposite wash at rest (less than my other EZB's), but my motor stick is about 10 mg lighter than yours.  Of course, it all depends on the amount of torque you want to launch the model.   You should be able to launch at a higher torque than mine.

-Kang
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