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Old Apr 18, 2005, 01:53 AM
Crazy Heli Technogeek
Kai_Shiden's Avatar
USA, WA, Seattle
Joined Sep 2004
4,205 Posts
Build Log
Profile SU-37 Design/Build Thread

I started this design/build in some of the Ikarus SU-27 threads. I made some modifications to my Ikarus right off the bat (Thrust vector paddles, rudders, and canards), turning it into a full blown SU-37 conversion. I really like how it performs, but decided to design it up from scratch instead of trying to mod it more. The Ikarus design would have required more work to improve further than starting over would take.

I've been working on this design since the early last week (modeling it on my computer). I'm done with the design work and am getting ready to build the prototypes (before further revision to the plans). Once I get the prototypes finished and test flown I will fix the plans and post them in this thread.

Click on any of the following images to go to the full size image in my gallery:

The model that inspired me to do this

Click here to see a video of it in action (warning, this is an 8meg Divx 5.0.5 file, you will need the codec to view)
NEW VIDEO IN MY GALLERY!!! (WMV format)

Renders of the custom model

Note: The above template render layout was changed for the finalized version, but the finished model will look the same.

Start of the build

The above pictures outline a build of the 20" version, the templates fit on a single 14"x39" sheet of 3mm depron.

Tomorrow I will post pictures of the cutout parts and the initial test fit. I have this week off work so I hope to post plans for both 20" and 30" versions around the end of the week.

-Kai

UPDATE: Plans have been published in post #65 on page 5
UPDATE2: Revision #3 full-sheet templates in post #184 on page 13
Link to Rev2 plans post
Rev3 16.5" full-sheet templates post
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Last edited by Kai_Shiden; Jan 24, 2006 at 12:00 AM. Reason: Set category (Look had too bright a color, hehe)
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Old Apr 18, 2005, 08:40 PM
Crazy Heli Technogeek
Kai_Shiden's Avatar
USA, WA, Seattle
Joined Sep 2004
4,205 Posts
Parts have now been cut out with my hot wire cutter, I'm getting ready to start glueing (too bad my darn carbon flat rod hasn't shown up yet).

I think I may have made too many interlocks, I was designing it to be as rigid as possible without adding weight, or weakening the structure. For those using an exacto to cut this out they may want to make it with 3/5ths the interlocks (I will put notations on the final plans for which interlocks are optional), just to speed up the cutting process. For me I like having this many interlocks, and I feel the structure with them is just as light as without, and stronger (less torsional twist than the Ikarus design).

As with the previous post, click on either of the following images to go to the full size image in my gallery

All the parts layed out:


Parts dry fit together for the test fit:


Everything fit together as expected, I had a few incidents while learning to use my new hot wire cutter (some minor nicks, nothing major enough that I would need to remake any of the parts).

I forgot to mention in the first post, that I am designing a center scale fuselage replacement section that will make it look more like the real jet, and improve it's flight characteristics when in wind outdoors.

-Kai
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Old Apr 19, 2005, 06:35 AM
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Geecee's Avatar
Suffolk England
Joined Jan 2005
78 Posts
Hey Kai
Looking good - the hot wire cutter really does the job. Would be interested in the plans when you are ready to release them especially with the scale fuse. Hope all is well with the maiden and keep us all posted.

Geecee
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Old Apr 19, 2005, 07:44 PM
Crazy Heli Technogeek
Kai_Shiden's Avatar
USA, WA, Seattle
Joined Sep 2004
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Thanks Geecee,

Many of the things I'm doing in my first prototype aren't necessary, such as working canards, double layer wing surfaces, working rudders, variable pitch prop, etc. I'm planning on eventually putting the scale nose pieces onto this prototype as well, I think it will not only make it look much cooler, but make flying in crosswinds much easier.

I've take another look at the design, with the scale body portions on it would be possible to convert this design to a single EDF40, however it wouldn't have the thrust to weight that a CD-Rom or Razor brushless would provide at this scale (the 30" could possibly be done with twin EDF55's if extreme outdoor speed was desired ).

The prototype assembly is going quite well, I have the canards mounted, the skins sanded to give the wings some shape, and some of the carbon internal reinforcements glued in place (I'm putting some 3mm by 0.5mm strips, in between the 2 layers of depron for addtional durablilty). Without all of the optional portions it could have been completed in a fraction of the time.

Here are the pics:

First Pic: Start of the assembly (this portion is without optional assemblies, the printout in the picture is an old render, it was all I had sitting around)
Second Pic: Optional parts are now all cutout, this picture shows the wing skins and some of the internal carbon reinforcements.
Third Pic: Closeup of the canard basswood hinge points, later pics will show how the linkage will cross to make them react properly to elevon control.

These are all the pictures I have for now, my camera battery just died so the pics of the airfoil shapeing will have to wait for a later post.

-Kai
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Old Apr 20, 2005, 05:06 PM
Go Sabres!
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Laurel, MD
Joined Aug 2004
816 Posts
That is awesome!!!! You must post plans. Sometimes because of the creativity I love the profiles more than full planes!
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Old Apr 20, 2005, 05:55 PM
Crazy Heli Technogeek
Kai_Shiden's Avatar
USA, WA, Seattle
Joined Sep 2004
4,205 Posts
Well, I'm pretty far along now. It's ready for electronics, I'll be shooting for a maiden flight this weekend.

My 20" airframe as pictured weighs 2.25oz (63.9 grams), this is no electronics or control rods, but is smooth skinned (double layered 2mm + 3mm depron for all control surfaces). It could probably be build to around 1.5oz bare airframe if everything was single layer 3mm. I'm shooting for around 6oz to 8oz ready to fly (I want it a bit heavier so it will skid through the air)

This update deserves a bit larger photo:

Click on the picture to go to a larger one in my gallery

-Kai
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Old Apr 20, 2005, 06:17 PM
PROFESSOR TRUTH JIMMY ICE
Akura2's Avatar
United States, CA, Los Angeles
Joined Sep 2003
6,660 Posts
So the canards are fully functional and in opposition with the main control surfaces?.... hmmm that thing is going to be able to flip like an acrobat if you want it to
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Old Apr 20, 2005, 06:33 PM
Crazy Heli Technogeek
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USA, WA, Seattle
Joined Sep 2004
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Yes Akura2, once I get the electronics mounted I will post a video of how the controls work. My modified Ikarus loops in just a few plane lengths, I'm attempting to make this one be able to flip while maintaining a straight line trajectory (hence the variable pitch prop). I want to make this thing perform like a 3D shockflyer, but still look like a jet. I've always loved jets, and have never been able to bring myself to appreciate the look of a normal prop plane configuration.

The Elevons are still a hybrid of how the Ikarus SU-27 works, the canards will be hooked to the other arm of the servo (180 deg from the arm that drives the wing and tail surfaces), but the linkage will be crossed from left to right (this will make the aileron portion of the elevon mix behave correctly). I designed it this way so that all the control arms would still be mounted below the control surfaces and less visible.

-Kai
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Old Apr 21, 2005, 03:51 PM
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USA, WA, Seattle
Joined Sep 2004
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I just took a little video of how the canards work. I don't yet have the wing elevon linkage hooked up yet, that's what I'm working on next.

Closeup detail of the crossed linkage:


Video of the Canards in action:

Note: this video is in Divx 5.0.5 format, you will need the codec to view

-Kai
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Old Apr 21, 2005, 10:05 PM
PROFESSOR TRUTH JIMMY ICE
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United States, CA, Los Angeles
Joined Sep 2003
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Wow... that thing is going to spin like a drill with the canards linked as ailerons as well as elevator.... can't wait to see it fly
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Old Apr 23, 2005, 03:37 AM
Crazy Heli Technogeek
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USA, WA, Seattle
Joined Sep 2004
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Yup, I'm hopeing to have good roll rates even when flying in high alpha (6 or 8 control surfaces tied to the elevon servos, depending upon if you count the vector plates separate of the rear elevons).

It's finally ready for the maiden flight tomorrow, this thing should roll unbelievably fast when at high speed (I've dialed in a ton of expo just in case for the maiden). It came out to about where I wanted it to at 8.5oz with battery (a 3 cell 880mah Lipo).

The motor is a 22mm 17turn CD-Rom motor I had laying around (I built it originally for a micro heli that weighed 11oz), the prop is a tail rotor from a MS Hornet II (I put my hornet in a Comanche body, so it was left over). Currently my linkage for the variable pitch prop isn't optimal, the motor moves a bit so it isn't precise (I have to build a brace that goes from the servo to the motor).

Thrust is unknown at this point, as I don't have a way to measure it, but at mid pitch it pushes up into my hand overcoming it's own weight. Higher pitch and I think the blades stall, as it doesn't give higher thrust, but it should be usable in flight at high speeds once the prop unloads.

Some pictures of the layout:

A little video of the controls:

My darn camera requires me to hold the button down while doing video, working the controls with just my left hand sucks.

-Kai
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Old Apr 23, 2005, 05:49 AM
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Kuala Lumpur, Malaysia
Joined May 2002
249 Posts
Hi Kai!
Keep the pictures coming..

Thanks

erunway
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Old Apr 25, 2005, 02:25 AM
Crazy Heli Technogeek
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USA, WA, Seattle
Joined Sep 2004
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Ugh , the test flights went awry, I went out to 2 different parks over the course of the weekend, and had some unexpected problems each time (never got more than a couple seconds flight), each time it was a power system problem. I'm wishing I had just designed it for my Axi from the start, at this point I've cut away too much foam for the CD-Rom to do a firewall mount for the Axi, without heavily modifying the airframe.

The first test flight was not my best judgement call, it was very windy and a thunderstorm was rolling in. I was at a friend's house for a barbeque, and I wanted to be able to show them the planes (he lives right next to a small park). It was too windy to fly my Ikarus (my Ikarus was blown halfway across the park in one gust, I ended up tearing the carbon reinforcement and some foam from the back of the wings, when it came down through a tree). I thought maybe I could get away with flying the larger model, I believed it would handle the wind better. Of course this was just where the problems started....

Before I left the house for the first test flight I loaded on the 1.12 PHX firmware then botched the settings, I forgot that it resets to default setting on firmware upgrade so it was having all kinds of timing problems (losing sync). Even with the sync problems, I found that none of the adhesives I tried would not hold the VPP hub to the drive shaft (it kept breaking loose on launch).

I guess 2mm is too small a shaft, it just didn't have enough surface area to hold the hub on with just loctite, CA, or epoxy (tried all 3 over the course of the weekend). Loctite worked when testing statically, but when set for good static thrust, it didn't have enough pitch speed when moving, and setting to a higher pitch for launch caused the shaft to break loose. I've put the VPP on hold for now, until I can make the parts to do it in 3mm with a securing pin.

In the meantime I tried putting a standard prop on it but ended up breaking it during a glide test (with the motor on the bottom, the prop broke when it touched down in the grass). On the upside, it glides farther than my Ikarus does because of the shaped airfoils. I have since moved the motor to the top of the plane like the Ikarus design.

There was a funny test launch where I tried to land immediately, I gave it full elevator to stop it, it did a cobra even though it wasn't even moving fast enough to maintain level flight. I've since retuned it so that I only have 50% dual rates until I hold down a momentary stunt switch, until I figure out what control range works well.

At least I still have my Ikarus to fly when I botch the test flights of the prototype. My Ikarus has definetly seen better days, I need to remake it as it has so much tape and glue on it now I'm beginning to feel the difference in flight, I don't have access to an accurate scale anymore but I know I've put on almost the entire roll of tape that came with the plane . It no longer launches straight up unless I give it a toss. Before all the repairs I could just hold it by the canopy area, throttle up to full, and let go of it, it would take off straight up on it's own.

I'm going to rescale this design down to the Ikarus SU-27 size, make a simpler tail system (lighter weight, easier construction), make it as light as possible, then move my electronics over. I've found that I have orientation problems after multiple snap rolls (since my Ikarus has rudders I have found it can snap roll unbelievably fast, and it looks darn cool doing it). On cloudy days up here the top and the bottom just don't have enough contrast against a grey sky at a distance away.

-Kai
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Old Apr 25, 2005, 04:58 PM
Registered User
Lincoln Municipal, Nebraska, United States
Joined Mar 2004
36 Posts
Hang in there. You have an agressive design going not only with the airplane but the controls also. Bound to be a few bumps in the road. Look forward to more of what you have going with this airplane. Keep us posted with everything your doing. It is a great read of the design and your thought processes of the "why" of the design.
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Old Apr 25, 2005, 08:16 PM
Crazy Heli Technogeek
Kai_Shiden's Avatar
USA, WA, Seattle
Joined Sep 2004
4,205 Posts
Thanks markn, I'm definetly going to stick with this design all the way through, from the few short flights (if you can call them that) I can certainly tell it's doable (roll stability has been rock solid). It handles much more radical than my Ikarus, which is exactly what I've been going for. I've found my 'problems' over the weekend to be more funny than setbacks.

I'm learning new maneuvers with my Ikarus every time I fly it, and I keep drooling over what this one will be capable of once I tune it. I'm pretty new to planes, I've only been flying the Ikarus (my first plane) for a little over a month, my helis became too expensive to be the only things I fly/crash. I'm still flying the helis, but not nearly as much since these foam planes are so easy to put back up in the air.

My car gave up the ghost late last year and I have been saving for a better car (hence the attraction to DIY foamies), so I've only been able to get out to the parks on the weekends. My only mode of transportation right now is my motorcycle, which I haven't been able to figure out how to carry a plane or heli on. I'm picking up another car this friday so progress on the plane will go much faster once I'm able to zip to the park on the way home from work.

-Kai
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