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Old Dec 18, 2010, 02:50 AM
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Lantsov Alexey's Avatar
Russian Federation, Saint Petersburg, St Petersburg
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Old Dec 18, 2010, 07:30 AM
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Sverige, Hallands Ln, Varberg
Joined Jul 2006
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what weight are you up to now?

How are you going to stick the mylar to the carbonfiber?

Super nice plane by the way. Hummm, now i have to build one for my selve
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Old Dec 18, 2010, 08:11 AM
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Now weighs 21 grams.
Weight is wrapped with a painting and be no more than 30 grams .
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Old Dec 18, 2010, 04:24 PM
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Made by the elevator and rudder.
Radius is made of 3 rods twisted.
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Old Dec 19, 2010, 06:30 AM
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Michigan
Joined Aug 2002
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In the final analysis

Alexey,

I've been watching your build of the CF/Mylar Sultimate and you are to be applauded for the technique you have developed. Hats off to you!

Weeks ago I decided to build a test CF Mylar plane to see what happens when the proper materials are not available. Here are a couple of pictures of the test plane and info on the weights of the build.

I had originally wanted to build your Relax but I can see now that without the proper materials it would be a fruitless endeavor in the weight department.

I will continue to watch your Sultimate build and save all of your techniques for a future project.

Here is info on my build in grams.

Airframe is 950m long and 860mm span.

Before After
Rudder 1.9 3.4
Elevator 2.5 3.3
R A 3.5 4.7
L A 3.5 4.7
SFGs 1.7 2.4
Fuse Bottom 4.0 6.0
Fuse Top 4.2 6.5
Plan view 11.1 14.1
___________________________________
Total 32.4 45.1
Weight of covering w/balloon Mylar = 12.7

Total airframe weight with, push rods, covering and bracing = 54.6

Add servos 14.1 + Rx 2.8 (16.9) = 71.5

Choices of motor, prop and esc

1. 9 gm motor + 8 gm esc + 4 gm prop + 160 cells 8.6 gm = 29.6gm + 71.5 airframe = 101.1 AUW
2. A10 15s + X5 = 21.2 + prop 4 = 25.2 + 250 cell 15.4 = 40.6 + 71.5 + 112.1 AUW

What went wrong with the weight?

Not having 6x0.1x 1000mm CF rod for the backbone is probably the #1 problem which causes about a 10gm penalty for this kind of build.
Not having a 9x2 2gm prop is another 2 or 3 gm penalty.
Not having the proper Mylar adds about another 7 gm penalty
Weight penalties for not having the proper materials = about 20 gm.

Best regards,

George

BTW, I've been meaning to ask. Your first name is Lantsov? Correct?
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Old Dec 19, 2010, 09:36 AM
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Madison, Alabama USA
Joined Oct 2005
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Ampbomber thanks for sharing your similar but different build info and interesting photos.

It looks like you may have covered both sides of some or all surfaces. That surprised me a little and may have added some weight.

The one thing that really confused me was the before and after weights. What are you comparing to what?

Jim, who is simply amazed and thrilled by this new build technique and who hopes to get the right stuff and to build something this way some day to use his smushed up UM4s, Sukhoi and/or Mustang gear.
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Old Dec 19, 2010, 11:21 AM
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[QUOTE=Jim_Marconnet;16864298]Ampbomber thanks for sharing your similar but different build info and interesting photos.

It looks like you may have covered both sides of some or all surfaces. That surprised me a little and may have added some weight.

The one thing that really confused me was the before and after weights. What are you comparing to what?

QUOTE]
Hi Jim,

No, only one side was covered with "Party City" balloon Mylar. I bought some
18" round baloons and used the Mylar from them. At first glance I thought that this Mylar would be quite light. The before and after weights are the respective CF parts of the of the plane before and after covering with the balloon Mylar. Alexey said he had covered his entire plane with 5gm of Mylar so the balloon Mylar weighs about 2.5 times the Mylar that Alexey used. The excess weight of the balloon Mylar comes from it being painted on one side and silvered on the other side. While using it I noticed that the paint comes off with alcohol and the silver side seperates from a very, very thin clear Mylar base. Before beginning a model like this it would be wise to find some very light Mylar.

The other part of Alexey's build that saves a considerable abount of weight is the CF tube he uses for a backbone. A 1000mm tube that weighs 2gm is impossible to find locally. Using the tube allows him to save a lot of weight because he drills holes through it which allows him to use uncut pieces of
1mm rod slipped through the tube for the wings and the tube slides through the vertical uncut split CF fuse cross members made in one piece.

Since Alexey has the CF Sultimate frame completly assembled now I am curious to see how he attaches the Mylar to the airframe. I'm sure he will be posting pictures soon of the covering aspect.

Another aspect of the build is the number of CF rods needed for a plane of his size. My estimate is about 17 1mm and 20 0.6mm rods. At retail that amount of rods cost about $80 US.

I'm going to sit back and watch the "Master" finish the CF Sultimate.

George
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Old Dec 19, 2010, 04:19 PM
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Russian Federation, Saint Petersburg, St Petersburg
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Weight Parts "Relax":
Propeller - 9x2 (homemade) 3 gr .
Motor 18-3/40 (homemade) 8 gr .
Servo D 47 S x 3.......................11 gr.
Receiver spektrum 6300.........1.5 gr .
Controller XP-7A.....................2 gr.
Acc 7.4 v Hyperion 130 ma 3G..7.5gr.
Total : 33 gr .
If you want to make the plane very light and strong, then repeat my decisions.
Many people do on his own and then wonder why out badly.
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Old Dec 19, 2010, 04:55 PM
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Michigan
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Quote:
Originally Posted by Lantsov Alexey View Post
Weight Parts "Relax":
Propeller - 9x2 (homemade) 3 gr .
Motor 18-3/40 (homemade) 8 gr .
Servo D 47 S x 3.......................11 gr.
Receiver spektrum 6300.........1.5 gr .
Controller XP-7A.....................2 gr.
Acc 7.4 v Hyperion 130 ma 3G..7.5gr.
Total : 33 gr .
If you want to make the plane very light and strong, then repeat my decisions.
Many people do on his own and then wonder why out badly.
I have no problem matching the equiptment side of your plane but the airframe weight you have is out of my reach without the proper supplies such as the 1000mm 2gm tube. Right from the start the airframe will be heavy without the tube you use. Without the tube your construction method can not be copied.
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Old Dec 19, 2010, 08:05 PM
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United States, CA, Los Angeles
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The longest portion of the central tube appears to be aluminum. Only the front few inches/cm's look like carbon tube. You can see the splice about where the nose would meet the wing leading edge. That's where the diameter changes to a smaller size as it extends to the tail. I've never seen shiny silver carbon tubing as shown in his photo.

If it is aluminum, can you please tell us what diameter and wall thickness it is?

Thank You
Michael
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Old Dec 19, 2010, 11:28 PM
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Michael .
http://www.rcgroups.com/forums/showp...9&postcount=54
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Old Dec 20, 2010, 12:30 AM
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United States, CA, Los Angeles
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Thank You ! I had seen those photos, but I had forgotten about the description you supplied of the central tube. Why did you apply the mylar to the tube ?

Cheers

Michael
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Old Dec 20, 2010, 03:17 AM
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Russian Federation, Saint Petersburg, St Petersburg
Joined Jan 2009
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A single layer of carbon fiber is very fragile. Mylar restrains the crack.
Ampbomber .If the 6 mm carbon tube is unavailable, you can use a 6 mm rod of balsa .
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Old Dec 21, 2010, 01:37 AM
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What's the main role of central tube?
Thanks, Alexey.

Samuel.
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Old Dec 21, 2010, 05:20 PM
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By means of a photo and a personal meeting with Alexey, has collected the plane
The YAK - now it weighs 26гр
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