Skymaster L-39 Assembly and Scheme Change
04-25-2012, 08:30 AM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: gamalierlozada
I want to see the final outcome of this build. I ordered a FeiBao L-39 (Edf version) and have been talking to Mike Warren to see which fan version would benefit my application. Also been talking to other respected EDF builder from Down Under (no name mention since this is a Schuebeler thread and I respect that
) and I will decide between those 2 units. So far the Schuebeler numbers look more appealing but unit weight is also a decisive factor. That's kind the only thing I would love this unit to be a little lighter a 2-2.4 pounds. That would be awesome considering the power it produces. Let's see what is Daniel's input for my application. Good luck with your build!
I want to see the final outcome of this build. I ordered a FeiBao L-39 (Edf version) and have been talking to Mike Warren to see which fan version would benefit my application. Also been talking to other respected EDF builder from Down Under (no name mention since this is a Schuebeler thread and I respect that
) and I will decide between those 2 units. So far the Schuebeler numbers look more appealing but unit weight is also a decisive factor. That's kind the only thing I would love this unit to be a little lighter a 2-2.4 pounds. That would be awesome considering the power it produces. Let's see what is Daniel's input for my application. Good luck with your build!
Daniel, Mike or Stu (Down Under guy) won't steer you wrong. They are all straight shooters and will tell you if a fan will or won't work, instead of just trying to sell something to you.
Most of the weight in the Schubeler fan is in the motor. Schubeler did a lot to shed weight off of these newer versions of the HST fans while increasing the power output and all of them are under 3 pounds. So, if you've been reading on the other site about how the DS-94 HST weighs over 3 pounds, keep in mind he is referring to the 1st version of the fan and not the newest versions. Actually, when using an EDF to power one these larger turbine airframes, a few extra ouncesin motor weight won't make a difference in how the plane flies but it will make a difference in the longevity of the motor because a motor with more mass dissipates heat better.
Kirk
04-25-2012, 08:36 AM
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RE: Skymaster L-39 Assembly and Scheme Change
This project is going on hold for a couple of weeks. I just received the Flying Legends Hawker Hunter. The fan for the L-39 won't be shipped until mid-May and I have all of the equipment to put the Hunter together so, I'll get back on the L-39 once the Hunter is done.
Kirk
Kirk
04-25-2012, 10:21 AM
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RE: Skymaster L-39 Assembly and Scheme Change
The stock inlets radius as per Feibao measurements to the center of the lip is 50mm which gives a inlet area of 7,850mm^2. Which is kind of small for a 120mm unit. The wingspan of the plane is 1440mm (57.750) and length is 1900mm (74.750). The exhaust outlet is 73.43mm (2.812") but that is from the turbine pipe measurements. I have seen the pictures of the area and the former that holds it in place can be enlarged, removed or replace for something larger. Mike is talking to Daniel for options and Stu is also looking for a Neu 1527/1.5y for testing in his newer 120mm unit. Right now I'm down to those 2 companies, it will be a mather of plusses and minusses because I can't go wrong with neither of them. Excellent guys and they are straightforward persons. If something will not work they will be the first to say it. And FSA is not a big issue at all because I can re-do the fuselage and fan inlets as large as needed.
Thanks for the advise!
Thanks for the advise!
04-25-2012, 03:28 PM
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RE: Skymaster L-39 Assembly and Scheme Change
That one is a little smaller than the one I'm working. Based on the numbers above, the intake area is in the 110mm fan range. If you wanted to run a 120mm fan without having to open the intake area, you're in luck because the DS-77, while being classified in the 120mm fan class, has a FSA 77cm62) of a 110mm fan class.
My recommendation for the FeiBao L-39 would be the DS-77 6740-650 on 12 cells. It weighs 2.73 lbs and can handle 12 to 14 cells. Here's the numbers:
Cell Count: 12
Voltage: 44.4
Amp: 95
Watts: 4218
Thrust: 16.0
RPM:25,000
Cell Count: 13
Voltage: 48.1
Amp: 108
Watts: 5195
Thrust: 18.2
RPM:26,000
Cell Count: 14
Voltage: 51.8
Amp: 119
Watts: 6164
Thrust: 20.7
RPM:28,000
04-25-2012, 04:06 PM
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RE: Skymaster L-39 Assembly and Scheme Change
I have been analyzing the data supplied by Mike today and from all the version the one I'm leaning towards is the DS-77-6745-700 and I explain why. From the numbers bellow the one that pops right away is the performance increase from 12S to 14S. While at 12 it has a incredible 19.8 pounds of thrust and 5900W with a efficiency of 72%. If put in 14S set up it gains 5.4 pounds of thrust more. As right now I'm analyzing the weight penalties not for the fan (that's 3.36oz or 95 grams) but from the battery increase. I need to do a spreadsheet with the Schuebeler Lipo weights, Fan unit, etc. to determine the benefits of 14S vs 12s (Power vs weight). If I can stay below 19-20. I will take the plunge. And who knows maybe I can get a little discount if I end up ordering the DS-77-6745-700 and 6 7S 6300 battery packs. That's a hell of a buy anyway you look at it!
I will crunch the numbers and let you know.
Here are the DS-77-6745-700 numbers.
Cell count: 12
Voltage: 44.4
Amps: 134
Thrust: 19.8
Exhaust Speed: 315.0
Efficiency: 72
Speed RPM: 28000
Power Watts: 5950
Cell count: 13
Voltage: 48.1
Amps: 150
Thrust: 22.5
Exhaust Speed: 337.9
Efficiency: 72
Speed RPM: 29000
Power Watts: 7215
Cell count: 14
Voltage: 51.8
Amps: 167
Thrust: 25.2
Exhaust Speed: 360.9
Efficiency: 71
Speed RPM: 31000
Power Watts: 8651
I will crunch the numbers and let you know.
Here are the DS-77-6745-700 numbers.
Cell count: 12
Voltage: 44.4
Amps: 134
Thrust: 19.8
Exhaust Speed: 315.0
Efficiency: 72
Speed RPM: 28000
Power Watts: 5950
Cell count: 13
Voltage: 48.1
Amps: 150
Thrust: 22.5
Exhaust Speed: 337.9
Efficiency: 72
Speed RPM: 29000
Power Watts: 7215
Cell count: 14
Voltage: 51.8
Amps: 167
Thrust: 25.2
Exhaust Speed: 360.9
Efficiency: 71
Speed RPM: 31000
Power Watts: 8651
04-26-2012, 08:42 AM
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RE: Skymaster L-39 Assembly and Scheme Change
Here are the weights. Some of them are really conservative (fuselage weight, wiring). Thrust from one unit to the other @ 12S is similar, but at 14S I don't have any numbers from Stu and that's where the Schuebeler get really awesome power.
06-10-2012, 02:34 PM
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RE: Skymaster L-39 Assembly and Scheme Change
Now that the Hunter is completed and ready for maiden it was time to back on the L-39.
The fan arrived while I was converting the Hunter so the first order of business was to decide if I was going to go with an open ducted or close ducted setup. The intake area is enough to feed the DS-77 HST but the shape of the ducting is not ideal. It has two farely sharp turns by the intake openings. Even with the short comings of the intake ducting, I decided to go with the closed duct setup for a couple of reasons; The fan is mounted far enough back giving the air time to smooth out before hitting the blades and an open ducted system would still have to deal with the two bends in the ducting anyway (unless I completely cutout the ducting).
With that desicion made, it was time to make some ducting. The first thing I did was cut the old ducting out leaving 1/2 inch from the bend (Photos 1 & 2).
Next, I used carbon fiber to make an intake ducting adapter and an exhaust tube (Photo 3).
Photos 4, 5, & 6 show the ducting and fan installed.
Kirk
The fan arrived while I was converting the Hunter so the first order of business was to decide if I was going to go with an open ducted or close ducted setup. The intake area is enough to feed the DS-77 HST but the shape of the ducting is not ideal. It has two farely sharp turns by the intake openings. Even with the short comings of the intake ducting, I decided to go with the closed duct setup for a couple of reasons; The fan is mounted far enough back giving the air time to smooth out before hitting the blades and an open ducted system would still have to deal with the two bends in the ducting anyway (unless I completely cutout the ducting).
With that desicion made, it was time to make some ducting. The first thing I did was cut the old ducting out leaving 1/2 inch from the bend (Photos 1 & 2).
Next, I used carbon fiber to make an intake ducting adapter and an exhaust tube (Photo 3).
Photos 4, 5, & 6 show the ducting and fan installed.
Kirk
06-10-2012, 04:31 PM
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RE: Skymaster L-39 Assembly and Scheme Change
I found out that Aerospace Composites has carbon fiber sleeves in different diameters and it can expand and shrink as needed which makes creating custom ducting a breeze. You just need to make a foam plug do the ducting and then melt the foam with acetone or something similar. Here's the link, https://www.acpsales.com/Carbon-Fibe...d-Sleeves.html
Nice job in the ducting! My unit (DS-77-6745-700) should be here in 2 weeks from now. Can't wait to start assembling my plane.
Nice job in the ducting! My unit (DS-77-6745-700) should be here in 2 weeks from now. Can't wait to start assembling my plane.
06-10-2012, 05:25 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: gamalierlozada
I found out that Aerospace Composites has carbon fiber sleeves in different diameters and it can expand and shrink as needed which makes creating custom ducting a breeze. You just need to make a foam plug do the ducting and then melt the foam with acetone or something similar. Here's the link, https://www.acpsales.com/Carbon-Fibe...d-Sleeves.html
Nice job in the ducting! My unit (DS-77-6745-700) should be here in 2 weeks from now. Can't wait to start assembling my plane.
I found out that Aerospace Composites has carbon fiber sleeves in different diameters and it can expand and shrink as needed which makes creating custom ducting a breeze. You just need to make a foam plug do the ducting and then melt the foam with acetone or something similar. Here's the link, https://www.acpsales.com/Carbon-Fibe...d-Sleeves.html
Nice job in the ducting! My unit (DS-77-6745-700) should be here in 2 weeks from now. Can't wait to start assembling my plane.
https://www.acpsales.com/.2-mm-High-...ber-Sheet.html
To make an exhaut duct, you would only need to roll it and epoxy the seam. At .008 thickness, not sure it would hold up for intake ducting.
Kirk
06-10-2012, 06:51 PM
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RE: Skymaster L-39 Assembly and Scheme Change
Carbon sheeting was my first option but like you said I didn't knew if it would be enough. But I might use it just for the external looks of it because it just look killer!
06-10-2012, 07:40 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: R_Belluomini
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020" should do the trick with a wrap of carbon tow. Thanks for the link
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020" should do the trick with a wrap of carbon tow. Thanks for the link
Normally,I would agree with you but the 700kv version of the DS-77 and DS-94 HST fans move an amazing amount of air for there size, so I'm not so sure carbon fiber tow would be enough. The HSTfans take things to the next level +1. A simple comparison of the numbers can show that. Based on the reported numbers of the Dynamax with the 1915 motor, it's producing 15 pounds of thrust. You would need2 of those to be equal to the amount of thrust of the 700kv DS-94 or 1.75 of those to produce the thrust of the 700kv DS-77. That's a very large amount of air being moved by the HST fans. Everything we normally do to strengthen the intake ducting, needs to be rethought with the HST fans. You'll get a chance to see them perform at E-Jets.
Kirk
06-10-2012, 07:51 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: k_sonn
Hi Bob,
Normally, I would agree with you but the 700kv version of the DS-77 and DS-94 HST fans move an amazing amount of air for there size, so I'm not so sure carbon fiber tow would be enough. These fans take things to the next level +1. A simple comparison of the numbers can show that. Based on the reported numbers of the Dynamax with the 1915 motor, it's producing 15 pounds of thrust. You would need two of those to be equal to the amount of thrust of the 700kv DS-94 or 1.75 of those to produce the thrust of the 700kv DS-77. That's a very large amount of air being moved. Everything we normally do to strengthen the intake ducting, needs to be rethught with the HST fans. You'll get a chance to see them perfor m at E-Jets.
Kirk
ORIGINAL: R_Belluomini
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020'' should do the trick with a wrap of carbon tow. Thanks for the link
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020'' should do the trick with a wrap of carbon tow. Thanks for the link
Normally, I would agree with you but the 700kv version of the DS-77 and DS-94 HST fans move an amazing amount of air for there size, so I'm not so sure carbon fiber tow would be enough. These fans take things to the next level +1. A simple comparison of the numbers can show that. Based on the reported numbers of the Dynamax with the 1915 motor, it's producing 15 pounds of thrust. You would need two of those to be equal to the amount of thrust of the 700kv DS-94 or 1.75 of those to produce the thrust of the 700kv DS-77. That's a very large amount of air being moved. Everything we normally do to strengthen the intake ducting, needs to be rethught with the HST fans. You'll get a chance to see them perfor m at E-Jets.
Kirk
06-10-2012, 08:07 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: gamalierlozada
Carbon sheeting was my first option but like you said I didn't knew if it would be enough. But I might use it just for the external looks of it because it just look killer!
Carbon sheeting was my first option but like you said I didn't knew if it would be enough. But I might use it just for the external looks of it because it just look killer!
Kirk
06-10-2012, 08:30 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: gamalierlozada
To give you a clearer idea. The DS-77-6745-700 put out 25.2 pounds of thrust at 14S. The DS-94-6745-700 puts out 29.2 pounds of thrust at 14S. The watts are 8600 for the 77 and 9800 for the 94. Pretty incredible numbers for an EDF!!
ORIGINAL: k_sonn
Hi Bob,
Normally,I would agree with you but the 700kv version of the DS-77 and DS-94 HST fans move an amazing amount of air for there size, so I'm not so sure carbon fiber tow would be enough. These fans take things to the next level +1. A simple comparison of the numbers can show that. Based on the reported numbers of the Dynamax with the 1915 motor, it's producing 15 pounds of thrust. You would need two of those to be equal to the amount of thrust of the 700kv DS-94 or 1.75 of those to produce the thrust of the 700kv DS-77. That's a very large amount of air being moved. Everything we normally do to strengthen the intake ducting, needs to be rethught with the HST fans. You'll get a chance to see them perfor m at E-Jets.
Kirk
ORIGINAL: R_Belluomini
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020'' should do the trick with a wrap of carbon tow. Thanks for the link
Kirk a few wraps of carbon tow should give it enough strength for a inlet. If not the .020'' should do the trick with a wrap of carbon tow. Thanks for the link
Normally,I would agree with you but the 700kv version of the DS-77 and DS-94 HST fans move an amazing amount of air for there size, so I'm not so sure carbon fiber tow would be enough. These fans take things to the next level +1. A simple comparison of the numbers can show that. Based on the reported numbers of the Dynamax with the 1915 motor, it's producing 15 pounds of thrust. You would need two of those to be equal to the amount of thrust of the 700kv DS-94 or 1.75 of those to produce the thrust of the 700kv DS-77. That's a very large amount of air being moved. Everything we normally do to strengthen the intake ducting, needs to be rethught with the HST fans. You'll get a chance to see them perfor m at E-Jets.
Kirk
Kirk
06-10-2012, 08:42 PM
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RE: Skymaster L-39 Assembly and Scheme Change
11K???? That's some wicked power!! The numbers I posted were from the Schuebeler test lists, but I know the like to play conservatively. Man post some video once you start flying it.
06-11-2012, 09:34 AM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: R_Belluomini
The power potential of the HST fans are enormous....
The power potential of the HST fans are enormous....
Kirk
07-30-2012, 08:54 AM
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RE: Skymaster L-39 Assembly and Scheme Change
After weighing the parts I decided to do a winter scheme using flat paints instead of the gloss scheme I was going to do. A gloss scheme adds more weight than a flat scheme.
I have the base colors on the airframe now. I used Testor's flat white and FS 34079 Dark Green enamel on the top and FS 36440 Flat Gull Grey on the bottom. I used automotive door jam tape to get the soft edges. Total weight added was 5 oz. Marklings will come form Taylor Made Decals. I have a little touch up to do. After I get the marking on, I'll do some weathering.
Kirk
I have the base colors on the airframe now. I used Testor's flat white and FS 34079 Dark Green enamel on the top and FS 36440 Flat Gull Grey on the bottom. I used automotive door jam tape to get the soft edges. Total weight added was 5 oz. Marklings will come form Taylor Made Decals. I have a little touch up to do. After I get the marking on, I'll do some weathering.
Kirk
07-30-2012, 09:49 AM
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RE: Skymaster L-39 Assembly and Scheme Change
Looking good Kirk!! Mine is almost done. I just need to tidy up the wiring after testing and lay down the exhaust ducting.
07-30-2012, 04:28 PM
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RE: Skymaster L-39 Assembly and Scheme Change
ORIGINAL: gamalierlozada
Looking good Kirk!! Mine is almost done. I just need to tidy up the wiring after testing and lay down the exhaust ducting.
Looking good Kirk!! Mine is almost done. I just need to tidy up the wiring after testing and lay down the exhaust ducting.
Kirk