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Old Oct 09, 2012, 09:16 PM
EDF rules... :)
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T/A 37 Tweet/Dragonfly

Well what can I say its been a long time since I was able to work on this 3D model.
Its pretty raw but at the time i figured that I would be able to work on it again. After loosing a couple of old laptops with all my old cad programs on it I cant work on it any more than it is ATM. I decided to take the sections I had made for it and go ahead and build the plane. I had always wanted one.

After seeing Keith Sparks C130 http://www.rcgroups.com/forums/showt...highlight=c130 a few months back and a few of D-fasts projects http://www.rcgroups.com/forums/showt...0#post22957750 and Uncle Crash's project http://www.rcgroups.com/forums/showthread.php?t=1719658 I decided now is as good a time as any to start. Unfortunately I am not the modeler these guys are, just trying to have fun and keep learning...

I have a CNC machine but alas it is down because I am too cheap to buy a monitor for the old desktop that drives it so it wont be used. I did make up a few tools to cut the foam by hand that I found in Keith Sparks book "Building with Foam" - http://parkflyerplastics.com/cart/in...roducts_id=644.

The templates were made from heavy poster board and they work well enough but I think I will have to recut some of the parts over as I reclaim skills I have not used in a long time, I cut some parts of the fuselage over the last few days and it sorta looks like what I modeled..

I will post some pictures of the build tomorrow along with some pictures of the drawings/models. Here is a link to some of the pictures I had made of the 3d modeling. Pictures start on post 32 to 45 http://www.rcgroups.com/forums/showp...5&postcount=45

Cheers,
Eric B.
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Old Oct 10, 2012, 03:10 PM
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Hi Eric. I saw your Tweet in the side bar and figured I would come over and check out your blog. You have some cool projects going. You sound like me when it comes to breaking out the cash to buy stuff you need. I rather keep the money in my pocket for the just incase event. I need for big plastic wheels which has kept me from maidening my Chimera and my 70in. butcher bird is waiting too for its maiden just don't want to put the money in the tank to get out to the field. I look forward to seeing the tweet come together its a cool plane. I am going to go to the Jet meet at PMAC it is closer than my field club. I don't know if I will join next year. I am a bit perturbed at the club they keep raising the price on due's. They went to $100 bucks a couple years ago and now they say because the club is not doing good that next year $140 well I wonder why the club is not doing good you lost 40% of your members last time you went up to $100 and they will loose again with the price hike. I mean when Im only using the club 10 times a year because of hard times. Im sure not going to pay the money this year coming up. There has got to be better ways to get people to the meets. Hey forgot I was on the blog thread feel free to delete after you read this. Good luck with the build I will be back to check it out. Dave
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Old Oct 10, 2012, 05:04 PM
EDF rules... :)
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Hi Dave,

Yup I am a bit of a penny pincher...
Again the club I belong to went up to $200 this year after going several years at $150. There is a flying field closer to me that is owned by the county(public park) that I dont like the people who fly there but I may have to start flying there again because the money is just a bit tight right now.
I will post some pictures of the drawings I developed and used in this build so far. I still have to develop the wood parts needed to hold the retracts and of course the alignment cradle like the one I did for the F86D in my blog.
I wont delete your post, your not getting far off the thread subject which is the hobby not just the airplane...

Cheers,
Eric B.
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Old Oct 10, 2012, 06:59 PM
EDF rules... :)
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Here is the model I made of the fuselage with its parts put into this drawing.

Eric B.
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Last edited by AirX; Oct 10, 2012 at 07:49 PM.
Old Oct 11, 2012, 05:10 AM
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Looks like your off to a good start. I was rusty when I started cutting parts. You can see as I got back further the parts get better. I learned a little trick as I was cutting. I noticed if once I got to the templates on both sides if I just let go of the handle of the cutter and let the weight of it do the work and just keep the piece at a good steep angle where it couldn't get off the templates it would cut flawless parts unless I hit a nick or bad spot in the template. I actually started sanding them a bit. I also made me a smaller cutter that is like a sling shot which helped too. I used a couple eye bolts about 2 inches long so you can have a lot of room to tension the wire. Plus its great for when you need to put the wire into a center section just unbolt one side slide it threw the hole and bolt it back up. My other one was about 16 inches or so and was just too long for working with 2in. foam. Looks like the tweet is going to be good size from your ruler. What size fans? I like the wide low slung fuse it's a neat looking plane. Talk to ya later Dave
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Old Oct 11, 2012, 05:46 AM
EDF rules... :)
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Cool, thanks for the help. I will get back to it today and will try the tips you talk about.
The Tweet model is 51 inches long and 60 inch wingspan, I have a couple of CS70's going into it on 4s. I am shooting for a weight of ~5lbs and 600 in^2 wing area should give it a light wing loading of ~21oz/ft^2. It will have retracts/flaps.

Cheers,
Eric B.
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Old Oct 20, 2012, 09:21 PM
EDF rules... :)
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Well I am making headway on the TA37, the parts are coming together.
This is going to be a fairly large airframe.
I am getting better at cutting the parts but it is still a litttle warm in the shop to spend a lot of time.

Eric B.
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Old Oct 22, 2012, 06:49 PM
EDF rules... :)
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Well I want to give a litte background on my design strategy for my airplanes.
I like jets and mainly work on scale subjects of my choosing.

1. Define performance arround the wingloading.
I am shooting for a weight of 5.5lb which should yeild a wingloading ~22oz/ft^2.
I wanted a larger airplane that was fairly light weight. I have been using section cut foam for the fuselages for a while.
I bought Keith Sparks book on Building with Foam and I found his wing deisgn he has been using on large lightweight planes would be what I want to use in this airplane.

2. Select the powerplant that will provide that performance.
I selected the CS70/L2855-2300 on 4s. This has shown to produce 1.16Kg(2.5lb) thrust, this will put the power loading near 1/1.
The weight of this setup is pretty light, the motor is 97grams, the fan/motor/esc/battery will weigh in at 22.5oz.
Two will weigh at 45oz so the airframe will weigh arround the same so 90oz(5.6lb) all up weight very close to what I expect.
Even if I have less thrust or more weight the airplane will still fly easy and well.

3. Design the airframe arround the wing size selected which usually means the ducting will be large enough to fit the fan selected.
The section cut airframe will yeild the lowest weight for a foam that I can make, the finish will be Styrospray on top of the foam.
This will give a hard coating to the airframe, hopefully still lightweight, this will be the first time I have used this finish.

4. Complete the details of the design.
I will fill more of this in as I go along.

Cheers,
Eric B.
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Old Oct 23, 2012, 06:39 PM
2014 EDF JET JAM We be Jamming
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St. Louis Intl, Missouri, United States
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Nice work Eric!
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Old Oct 23, 2012, 06:56 PM
EDF rules... :)
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Hi Kevin,

Thanks I appreciate that.
I have been keeping up with your X32, she looks great.
I wish I still had the model of the foamy version I worked on.
I think it could have been scaled up and it would have been easier to cut.
The small 50mm size I had selected made it difficult to cut the parts.

All the best,
Eric B.
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Old Oct 24, 2012, 07:30 AM
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Looking good Eric.
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Old Oct 24, 2012, 12:39 PM
EDF rules... :)
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Quote:
Originally Posted by unclecrash View Post
Looking good Eric.
Hi Crash,

Thanks for that, but I think mine will be a lot more work than yours, my cutting was really terrible on the first few sections. The last two came out ok but it was a lot of work.
I keep watching your thread. Keep the pictures coming, it really gets me fired up to work on mine.

Cheers,
Eric B.
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Old Oct 24, 2012, 10:05 PM
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I don't know about that mine is giving me some fit's. Im working on it today some pics by tomorrow or the next day.
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Old Oct 25, 2012, 06:38 PM
EDF rules... :)
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Hi Crash,

Work on the fuselage parts is not easy for me at the moment either, more or less the day job is wearing me down. I might be able to get more done this weekend. Keep at it you 23 is really looking good.

Eric B.
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Old Nov 05, 2012, 09:59 PM
Gustaff
Guatemala
Joined Aug 2008
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Great!

Have you considered to draw/sell plans for this? I have been looking for a plan for the Dragonfly for years, I love this plane.

Will follow this tread a close as it can be done.

Suscribed,
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