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        Discussion Aileron Vapor

#1 Gordon Johnson Mar 27, 2010 10:18 AM

Aileron Vapor
 
3 Attachment(s)
Here's my conversion of a Vapor to have ailerons. At our last indoor my daughter's brand new Vapor had a mishap with a Sukhoi and had its tail covering stripped off. So, I ordered her a new one and attacked this one. My older son has been wanting to fly my Airbender so I thought I'd convert this Vapor and let him fly it.

My estimate is that the NET increase in weight over a standard Vapor will be about 2g. But, that comes after putting this Vapor on a diet and saving 1.5g or so in weight. I recovered the tail with lighter clear film and painted on some blue and a fake skeleton to sorta mimic the wing. I'll be using a Sukhoi brick and servo rather than solder a servo to the Vapor brick.

[edit] I made my own tail, which increased the weight gain (plus a few other things) to 3g over the stock. I've added the picture with my tail below, along with the version with the stock tail recovered and painted.

When I'm done with this conversion I'll post the plan for the wing and related bits for those who may want to do this themselves.

Gordon

#2 Gordon Johnson Mar 27, 2010 10:18 AM

2 Attachment(s)
The first thing to do is cut off the old wing. But, we want the molded plastic wing saddles. I cut off the wing right where the CF rod goes into the plastic wing saddles. Corresponding slots are cut in the foam wing. The wing saddles get glue applied and are inserted in the slots in the wing when glueing the wing on.

I also cut off the lower plastic part from the Vapor center wing rib to save weight and because it will interfere with the foam that will hold the servo and bellcrank.

The wing is very similar to my Airbender wing. Its span is the same as the Vapor wing so with a bit of modifications to the foam carrying box it will fit into the original Parkzone box for transport. Foam is cut from either 3mm Gediplac or Depron and covered with 2 um film from Dave Lewis (homefly.com). The film from Dave has the advantage of weighing 1/3 that of the covering that's used on the Vapor. The wing with outer two ribs (but not the center rib that holds the servo) weighs almost exactly the same as the Vapor wing that was cut off and removed.

#3 Gordon Johnson Mar 27, 2010 10:19 AM

4 Attachment(s)
I cut a center wing rib from 3mm Gediplac. This will hold the servo and also the bellcrank. Similar to my Airbender, the bellcrank is made from 1/64 ply and uses a BSD molded plastic wheel hub and keeper and short length of piano wire for it all to pivot on. Three stacked squares of 1/32 ply serve to hold the piano wire and anchor it into the foam center rib.

The center rib has UHU Por applied and is glued on the right hand side of the plastic Vapor rib, underneath the plastic lip.

The Foam center rib and wing saddles get UHU applied and the foam wing is glued in place. Note the wing saddles inserted in the slots on the wing.

#4 Gordon Johnson Mar 27, 2010 10:19 AM

1 Attachment(s)
I glued in a small rectangle of 3mm foam just behind the forward wing pylon. The purpose of this is to give the CF wing struts something to anchor into. I cut shallow grooves in the sides that will be glued to the fuselage rod and the forward wing pylon. Then, pressing the piece on these rods spreads this groove slightly and makes a channel for the glue and will result in a very strong joint.

Wing struts are poked through the foam and cut to length. Foam safe CA is applied to each end and each strut is installed. Care needs to be taken to get this right so the wing is not warped. I used 0.8mm CF tube for the front struts and 0.5mm CF tubes for the aft struts. CF rod came from homefly.com.

Landing gear is my replacement Vapor landing gear design. To save a bit of weight I used 0.5mm CF tubes with piano wire axles rather than the entire strut from piano wire. Added weight over the standard gear is about 0.13g.

#5 Gordon Johnson Mar 27, 2010 10:20 AM

reserved for future content

#6 Gordon Johnson Mar 27, 2010 10:20 AM

reserved ...

#7 I R Irv Mar 27, 2010 01:00 PM

Gordon couldn't you make a wing strut mount like your landing gear mount that way you could still slide your wing forward and backward possibly two of them one in front one in back.
I can't wait too see this one fly wish I lived buy you. TODD

#8 Gordon Johnson Mar 27, 2010 01:04 PM

Todd,

I thought about that. First, the landing gear ply mount is heavier than the piece of foam I went with. Two of those types of mounts are twice as heavy. And, with one in the back and one in the front you give up the triangle configuration. The wing will twist because the two wing struts and the wing and fuselage form a parallelogram rather than a triangle. To get any reasonable stiffness and no twist would require larger diameter CF rods. With a triangle configuration I can use the minimal diameter CF rod and save weight. The triangle method I used here is the same as what I used on my Airbender. The only difference is instead of the fuselage being made of foam where I leave a spot to pass the CF rods through I glued that piece of foam in. Also, my landing gear mount doesn't slide forward and back. It's fixed. I don't have any need to slide the wing on this forward and back.

Gordon

#9 pmackenzie Mar 27, 2010 01:12 PM

Cool project:cool:
Is that 2 mil or 0.2 mil?
I thought the Vapor was covered in 1/2 mil = .0005" mylar.
2 mil would be .002" - pretty thick.

Thanks,

Pat MacKenzie

#10 Gordon Johnson Mar 27, 2010 01:15 PM

Oops, you are right. It's 2 um film, which is 0.08 mil. I have corrected that post.

#11 I R Irv Mar 27, 2010 01:24 PM

Ok totally understand know to bad that little piece of foam can't slide on the frame. You really take this hobby to were most just dream of, it wouldn't be were it is without you.
TODD

#12 pmackenzie Mar 27, 2010 01:34 PM

Quote:

Originally Posted by Gordon Johnson (Post 14706161)
Oops, you are right. It's 2 um film, which is 0.08 mil.

That is very thin:)

#13 PeteSchug Mar 27, 2010 01:41 PM

Very interesting project. I am looking forward to hearing how it flies.

Pete

#14 Gordon Johnson Mar 27, 2010 09:07 PM

Quote:

Originally Posted by I R Irv (Post 14706062)
Gordon couldn't you make a wing strut mount like your landing gear mount that way you could still slide your wing forward and backward possibly two of them one in front one in back.
I can't wait too see this one fly wish I lived buy you. TODD

To give you a sense of the tradeoffs, the laminated ply piece for the landing gear weighs 0.15g. So, two of those for wing strut mounts would weight 0.30g. The piece of foam I used instead weighed 0.01g.

But, the big reason is still triangle versus rectangle. The triangle method results in a wing which is not only stiffened for up and down rigidity, but it doesn't twist either. Try it. Its surprisingly stiff and twist resistant. And, it allows the use of pretty thin and light CF rods. Also, the light ply method does't allow CF rods to come in at an angle, they have to be perpendicular to the fuselage stick (at least the way I do them).

That said, on my Der Jager bipe I had it so the landing gear mount also had two sockets pointing up, and I ran a pair of CF wing struts down into those sockets. However, on that plane the outer wing struts take care of preventing twisting, and I didn't have a second pair of struts angled aft. See this picture. http://www.rcgroups.com/forums/attac...mentid=2463236

I've never needed to slide a wing on a vapor forward and backward. I achieve CG changes by moving the battery.

Anyway try this wing bracing method and see how it performs. you might be surprised.

Gordon

#15 del Mar 27, 2010 10:28 PM

Good work, as always, Gordon!
I can't wait to hear your flight test reports.

As you might have guessed, I've been working on something similar (stick and tissue, of course..). The first couple of times I tried to fly it were, err, bad news.. But, third time's a charm this Monday at the gym..

Keep that laser cutter cookin'....

--del


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