|Sep 09, 2010, 08:40 PM|
Mirage 2000 -- 55mm EDF -- New Flight Video & PLANS ADDED (FINALLY!!!)
********UPDATE 3/23: PLANS DONE!!!!!! FINALLY!!!! IN THE FUTURE, I WILL ALSO ADD BUILD PICS OF THE FINAL VERSION. VIDEO OF THE COMPLETED PLANE IN ACTION!
In the video below:
55mm, 5250KV EDF
lipo: 1300-2200 3s
AUW: 17.8oz-20.4oz (depending on battery)
*****UPDATE 2/26/11: -- V2 Video!!! - see end of thread for details
Stats of completed, painted V2 model:
Airframe wt.:12.9oz (w/o battery)
AUW: 17.5oz (w/1300 3S 25C lipo)
Servos: 3x9g -- 2 for elevons; 1 for rudder
EDF: 55mm 4300KV
FSA Intake: 100%
FSA Exhaust: 85%
******UPDATE: I have completely redesigned this model for better handling and more scale appearance. I took another leap and decided to design V2 via computer. So far so good. Alpha plans are almost done and I will offer them up soon! More details about V2 at the end of the thread... I have added the latest plan pics below...
I've finally taken the leap and have come up with my own plans! Drawing inspiration from Jetset44 (S. Shumate) and other great parkjet designers, I decided to build my own from 3 - views.
I have a 4300KV aeo 55mm EDF that I originally intended to use on a Shumate F18 parkjet EDF conversion. I ended up squeezing a hotter 64mm fan into the F18 and couldn't be happier with the performance. So I decided to make a home for the 55mm. I wanted a jet with a large wing area, and that could be built light. I also wanted to be able to add a rudder easily. I came across the mirage 2000 and decided that it would be the one...
I found some 3-views and imported them into sketchup... I then used the scale and dimensioning tool to size my components. I am not that familiar with sketchup yet, so It was easier for me to draw everything out. If any are interested, I do plan on posting final plans once I arrive at a final design.
My initial design notes:
-Fuse would be sized to fit a 55mm EDF (70mm width including lip diameter)
-Landing Gear "Tray" -- detachable landing gear
-100% FSA intake
-90% FSA thrust tube
-AUW under 12oz
|Sep 09, 2010, 08:42 PM|
V2 Build Pics
V2 Build pics. Adding captions to these photos will be an ongoing process.
|Sep 09, 2010, 08:48 PM|
-Cut parts out of depapered Dollar Tree Foam (my foam of choice).
-Added carbon beam to wing, and assembled fuse.
-Also added elevons -- I then used the partial airframe to determine my CG -- She had a great glide!
|Sep 09, 2010, 08:55 PM|
Forgot to take pics of the installed EDF! I used a cut and formed styrofoam coffee cup to smooth the transition from the square fuse into the round EDF. I also installed a 4" thrust tube onto the back of the EDF. The outlet area is 90% FSA... Thrust tube was constructed out of photo paper. Also installed rudder servo into fin.
|Sep 11, 2010, 06:57 AM|
Airframe completed! AUW is 12.4oz with a 1600mah 20C 3S lipo. I also weighed the airframe with a 1000mah 20C 3s lipo -- 10.8oz. I love the lighter AUW, but I think that battery may be too small. I think something in the 1300 range would be perfect. I will find out for sure once I hook her up to the watt meter.
Next up: sanding, maiden, painting...
|Sep 11, 2010, 11:53 AM|
Sanded her into final shape, added some details, and took her out for her maiden. Conditions were not ideal as it was a little windy.
First I hooked her up to the watt meter -- Here are the stats.. my test battery was a fully charged 2200 30C lipo. The battery I plan to use in the plane is a 1600 3S 20C lipo...
At 12.4 oz, according to my calcs, I'm getting around 350W/lb. Which should be more than enough for good performance.
First launch attempt:
The only way to launch is with an underhand toss. tossed her out, the torque rolled her on her side and down she went -- I was able to roll her back, but couldn't gain altitude in time... she slammed on her belly and slid... phew -- no damage-- not even the nose cone!!!
Second launch attempt: angled her to the right a bit, 3/4 throttle, several clicks of up trim... tossed her out and up she went. Very strong climb out, very twitchy, and needed a lot of up elevator to keep her level (she kept heading down at neutral stick. I think she was tail-heavy. With all of the porpoising and rolling - It took me a while to get her under control -- very twitchy and does not self correct . Speed was good and manageable. Thrust was excellent, great vertical performance. The plane kept slipping into high alpha at slower speeds (tail heavy). Even with the trim and CG issues, I was still able to bring her in without a scratch...a successful maiden!
Things to do:
-move CG forward to eliminate tail heaviness
-add up trim to elevons
-strengthen duct seam. I will add a thin doubler strip along the inlet duct seam - it was bowing under pressure
I was very happy with the performance -- I don't think there will be a need to go lighter with a smaller battery unless the paint adds a lot of additional weight. Might still like to try a 1300 though -- especially if I add a "landing gear tray". Can't wait to make the above changes and get her out again!
|Sep 12, 2010, 07:08 PM|
Made the above changes, got her partially painted and took her out again today. This model is a beautiful flier -- I just had to remedy the CG issue, and strengthen the ducting. I moved the battery forward about 1.5". This moved the CG forward about 1/2". In flight I still needed to add several clicks of down and right trim to get her to fly level. But once I got her trimmed in, she performed beautifully:
- Rolls were lightning fast and axial;
- Speed envelope was excellent;
- High alpha was great with rudder control;
- She goes where you point her;
- Able to do really cool cobra maneuvers;
- Belly landing was a breeze.
It was a hazy day today, and even though the belly is still white, I almost lost orientation a few times. I was going to add some red trim, but I may alter my original plan to include more red for better visibility. I am also concerned about the toll belly landing will take on the bottom of the plane and the wing leading edges. I usually add packing tape to the portion of the plane that drags across the ground but I think covering the whole bottom surface of this plane with tape would add too much weight. A possible solution would be to add 3 tanks - 2-wing, 1-fuse. Not sure how they would affect flight or how much weight they would add...
Will add plans and video once I get everything finalized!
|Sep 15, 2010, 08:34 AM|
I made the Drop tanks -- decided on only two. I wanted them to be detachable, so they attach to the plane with velcro (simple!) They are made from laminated 3/4" insulation foam, cut and sanded to shape. I'm happy with how they turned out, but I am concerned about the weight. Together they weigh 1.1oz! The airframe with the drop tanks AUW is now 14oz! I have no doubt she will still fly well, but will suffer a loss in performance. My initial test flights were at a 12.4oz AUW.
I think I may have to remake them using rolled foam and sanded "endcaps" -- That should shed a lot of weight.
|Sep 15, 2010, 08:44 AM|
Here is the completed airframe ready for flight:
AUW w/tanks: 14oz
- redesign tanks to save weight
- trim control surfaces
- determine final CG and control throws
- update plans
After I get everything finalized, I will provide plans and video!
|Sep 15, 2010, 07:33 PM|
Thanks! Yeah, I may have to leave them off for good performance... I was hoping to be able to take off of grass and possibly pavement with them. Also wanted to do touch-and-goes! I tested the thrust with them and I still have over 1:1 but she is definitely suffering from the extra weight. I also did some "slide" taxiing (sp?) in my back yard today and she moved along the ground pretty well. I think she could definitely take off but I may need to adjust the angle of the tanks so she sits at a positive AOA to the ground. Good thing they are removable! I will definitely attempt to build hollow ones -- don't know why I didn't do that in the first place!
Hoping to be able to shoot video in the next few days! Then I'll get busy on the plans -- I have them on paper but I want to transfer them to digital format. I plan to learn google sketchup and do them with that program.
|Sep 15, 2010, 07:55 PM|
Joined Nov 2005
When it comes to EDF weight is definitely an issue. It does depend on how much speed you can get out of the EDF. If the speed is fast you don't really need the thrust. 98% of real airplanes don't have anywhere NEAR 1:1 thrust and they fly just fine.
I think you will do just fine as long as you have a good CG. I would check www.parkjets.com I am pretty sure they have a Mirage on there and you can get a good CG there. If not there are plenty of deltas that will give you a good idea. Just get out there and do it!
|Sep 15, 2010, 08:37 PM|
Yes! I have learned that the hard way! I feel like I am finally starting to get the hang of EDF power systems! It seems like its always a battle between power, thrust, and weight. Underpowered EDF's are a nightmare to me - imho, they are no fun to fly! I've learned to go lighter or go bigger!
My first flight, the cg was way too far back -- she was all over the place and I was lucky to get her back without a scratch. My second flight -- cg was good possibly a bit nose heavy. There's more than enough room to move my battery so I'm not worried about that.
Right now she has an AEO 55mm 4300KV EDF. Power was more than enough for the model when it was 12.4oz. -- had much more than 1:1 - even with 90%FSA exit. Lipo is 1600 20C 3S.
Yup, I checked cg's of several delta's including the mirage and gripen on parkjets.com. I also checked an online delta wing calculator. All gave pretty consistent results.
|Sep 15, 2010, 10:16 PM|
Awesome work SNice, Looks really simple to build and is pretty good looking too. I designed/built a scratch built Mirage 2000 based on jetset44's designs but that was too much foam cutting and work; I like your designs simplicity.
When you release plans I'll be sure to make one for a EDF 30/40 with 12/15 WS
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