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Old Mar 16, 2012, 02:31 PM
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Freddie B's Avatar
Omaha Nebraska
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27mm Republic F-84 Thunderjet, pre-'F' series.

Ok, been away from the Micro EDF Forum for a while. Things always come full circle don't they. I have had this in the back of the Gray Matter file for some time. I also promised Hu some time ago to put my AEO 27mm EDF into a flying bird.

So, I'm guessing that with the GP Sabre, Art tech, and all the rest, scratch building is a bit unpopular at the moment. My timing is never good is it. I guess I always just do things my way anyhow.

So without delay I will make my comitment: Either this will work, or it will be a complete failure and I will be the new class clown. I want a F-84 Thunderjet. Straight winged here, like the originals, pre 'F' model when they swept the wings hoping to boost performance. The Thunderjet was never a great performer. Underpowered, in the early days of jet aircraft, much effort went into trying to 'improve' it. What better to put the smaller, somewhat wimpy 27mm EDF into.

To me the Thunderjet is just plain sexy. I love the look on the ground and in the air. Classic and old timer, just my speed. So if you care to follow, fine. If not that's fine too. Love notes, please share. All hate mail should be addressed to Idontreallycare.net.

Already started this yesterday, so here goes. Wish me luck!
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Old Mar 16, 2012, 02:32 PM
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Omaha Nebraska
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This is a photo of the 3 view I am using for my only plan to build my Thunderjet. So typical I took and printed out my 3 view. It was 'whatever size it came out' kind of thing. I did some math for a bit and finally decided to make this around an all but scale intake and outlet size, so that worked out to a 325% enlargement. Cut the craap this means I am shooting for:

17.87" Wingspan (or close) LOL.
Major cord 4.55", minor cord 2.6", my wing area worked out to 69.69" SqIn.
Total Length should be 18.6225" or so.
The 27mm EDF Shroud is approximately 1.080" ID, 1.130" OD, 1.0" long, and has a bell shped intake ring of 1.425" Dia.

My best test results were 5.1A, 68g thrust, dropping to 4.9/5.0A, 7.6V, 65/66g thrust on a 800mah, 2 cell, 20c battery. I would gress a 350-500mah 30-40c battery will motivate the little fan real nice.

Welcome to Imperial measurements. Sorry my Metric buddies. I just can't think fast doing conversions on everything I touch. I'll be building in inches and decimals here.

I will try to build in lightness all the way through. plan on using a bunch of 1mm depron I got from RCFOAM.COM some time ago. Formers will be 3mm Depron for handling reasons. The rest is up for grabs at this point. I'm not against foam cups, plates, bowels or anything else that isn't bolted down. So if you take-out disappears, you know a scratch builder was in the fridge!

Fred
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Old Mar 16, 2012, 02:34 PM
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Omaha Nebraska
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Shooting from the hip.

Well typical I didn't make any plans, sketchup stuff, or CAD drawings. I am doing what I do best. Scratch build as I go. This is that part I mentioned. Either this works or it will be a complete failure. Of course that has never happened to me before. LOL. I am using the ductwork right off the bat as the building crutch. This makes for a very long duct and I fear it will be the death of the thrust my 27mm EDF puts out. I have had some luck with long ducting, but something tells me to keep a guarded eye out. Any thoughts?

What I can promise is I'll try to take lot's of photos so at least it's fun to watch.

I started with a piece of UV protected PVC conduit that is just about 1.0" in diameter. This is my mandrel to make my ducting. I rolled 1mm Depron around this, taper sanded the edges of my sheet and used my favorite Elmer's Rubber Cement as contact cement to bond it. UHU Por or Creative would work for those in different Countries.

I found that if a bit of the Rubber Cement dries where you don't want it, Lighter Fluid (Naptha) works great for removing it.

Fred
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Old Mar 16, 2012, 02:35 PM
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Reserving for photos.

I'll be back!

A famous Movie Quote by:

Arnold 'the Governator"

Sorry if this wasn't clear, that I was quoting a movie line. Arnold is one of my favorite actors. Anything contrary to my initial thinking of such movie quote is humblely apologized for if it offended anyone. A person's family name is not intended to be inflamitory. This is so not my nature or of my character. I condsider all RCG members to be regarded as my friends and fellow modelers. This is the greatest outlet for knowledge and advancement of our hobbies. I do hope those that know me, and those that are new to my postings understand my willingness to share and also receive the great benefits each and every member has to offer. I am proud to be a RCG Memeber, allowed to share and receive from around the entire World is such an awsome previlege. I am a simple man, father of 5 children, a Christian and proud upstanding American citizen. To all, peace and be generous with your time and knowledge. The world is a better place because of it!
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Old Mar 16, 2012, 02:36 PM
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Reserved for video, or apologies

50/50, place your bets early. If she fly's, video. If she fails, Apology!

Fred
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Old Mar 16, 2012, 03:12 PM
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Here is some data on the AEO 27mm EDF for you tech types.

Dr. Kiwis post on initial thoughts and showing the AEO test data sheet CLICK HERE.

Here is a copy of a post I did last year when I tested this 27mm EDF from AEO. Funny thing this post was made 16-MAR-11, and today is 16-MAR-12, awsome omen.:

Further tests today on the AEO 27mm EDF unit. I tried six different batteries I own that I felt could be within weight limits to make a well performing airframe to put this EDF Fan to the true test, flight.

Amazing that the Hobby King Flightmax, 350mah 2 cell (7.4V) battery almost had enough to push this fan, but not quite. It did hold it's voltage well, but just couldn't put out it's rated discharge specifications. (Video #1). Results were 4.5A, 57g thrust, setteling to 4.2A, 55g thrust. For it's weight, it still might be viable, but life span might suffer.

AEO 27mm T2 (1 min 0 sec)


I tried a seventh battery just for bench tests, a Hobby Partz, Blue Lipo, 800mah 2 cell (7.4V) rated 20c discharge. (Video #2). I feel this battery is too heavy for my airframe designs, but proves without a doubt that AEO is very accurate on their posted specs.
Results were 5.1A, 68g thrust, dropping to 4.9/5.0A, 7.6V, 65/66g thrust.

AEO 27mm T3 (1 min 9 sec)


I have ordered several batteries, and feel that 450-500mah packs will probably be the correct balance of price, weight, capacity, and discharge rates. The new 65c 350 packs may be good but pricy and un-tested.

I am the practical type. I want good value, and easy to achieve performance. I think AEO hit a winner on this one. From the average modeler point of view here are some very nice observations.

1. The motor has remained cool to the touch, even when running it WOT at 5.0 amps average.
2. The specifications are right on that 7.4-7.6V, 4.9-5.1A, puts out an honest 65-68 grams of thrust. This is fan pushing thrust stand against scale. No intake ducting or exhaust ducting.
3. I don't think I would want to push any higher performance out of a 27mm fan as the consumption of energy is at the top of the battery performance range of today's current cell capacity.

Thank you Hu, and AEO for the great EDF 27mm EDF unit. Airframe and flight testing next!

Fred
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Old Mar 16, 2012, 03:51 PM
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I'd like to be the first to congratulate you on your successful test flight....till then this spot is reserved . Cool project!
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Old Mar 16, 2012, 03:56 PM
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Freddie B's Avatar
Omaha Nebraska
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Making formers.

Formers are made from 3mm Depron. I guess I could have just enlarged my 'plan' to print out formers at 325%, but I hate the fat lines you get. So I am measuring and laying out these using pocket scales, circle template, and an ellipse template I found at the office supply store.

I am using te 60 Degree Ellipse forms, and the 1 1/8" circle template (fits perfect over my duct).

Some photos of this prototyping of my build.

Fred
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Old Mar 16, 2012, 04:04 PM
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Quote:
Originally Posted by pdawg View Post
I'd like to be the first to congratulate you on your successful test flight....till then this spot is reserved . Cool project!
Thanks Bret!

Guess what! Clean bill of health from Internal Med Dr. Means I'll be around a bit longer so you are all in trouble now. You are funny, and you are my favorite Dr. (almost Dr.) too BTW. You build cool airplanes.

Sooo... I have some 40mm AEO Rotors we need to tool up for. Never heard on the adaptors. I picked up some more GWS 001's. Send me a PM when you are ready to move forward!

Stay tuned! Thanks

Fred.
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Old Mar 16, 2012, 04:06 PM
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Next I marked my former station lines on the intake part of the ducting. This was achieved with the utmost care and precision. I have a top secret photo of how they do it in the Skunk works.

Fred
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Old Mar 16, 2012, 04:14 PM
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Formers set in position.

So you can note various markings on the duct/crutch. Station line marks, centerline alignment marks, etc. I then placed my formers on the duct/crutch, and finally glued them into position. Trying to keep everything square with the duct.

These formers are up to and including F5, which is at the trailing edge of the wing station line. Everything going eal smooth so far. The 1mm depron duct, with formers is light, and quite stiff (micro stuff here of course). The duct now stays nice and round when I pull my PVC mandrel out of the assembly.

Still charging ahead with full confidence.

Fred
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Old Mar 16, 2012, 04:25 PM
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Removable EDF for maintenance.

So now I had to put on my thinking cap, and work out a maintenace arrangement for the EDF installation. You know if it was mounted without access I would throw a rotor, crack a blade, or some other act of kindness from the EDF gods.

So some photos of my fabrication of a split collet type of thingy, using 3mm depron, glue, and design as you go type stuff. Common around these parts they say.

I sanded a clearance radius on some 3mm Depron strip so I could clear the intake lip, and not have to cut it off my EDF unit. I so hate destroying things in case I want to use them somewhere else later. (cheap skate). This was pre curved as was the ducting material.

Another slightly wider strip of 3mm Depron was fashoned, and curved also. The next 3 photos should clear up what I am doing. This is my split collet idea where the EDF will mount and be captured but remain removable.

Maybe it will make sence as we move along here.

Fred
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Old Mar 16, 2012, 04:30 PM
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United States, IL, Joliet
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Iam sighned up for another one Freddie ,iam in the repairing mode of my fleet ( mostly hanger rash )and not building for a while. joe
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Old Mar 16, 2012, 04:37 PM
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So hopefully these photos will clear up my thinking on the split collet arrangement. You can see how the foam will conform to the EDF Shroud.

Then one half (top piece) is glued in place to the formers, forever! I then decided that additional formers and partial formers were needed. Some split, some glued to one part, or another. We will see how this all works when I can do the final disassembly of this area and play with it.

Time to move on to the exit or thrust ducting, and aft fuselage crutch. BTW, this was all completed up to this point, 3 view, cut foam, glue, etc in one day. I did little bits and pieces throughout the day, with many other chores and life duties in between. Heck glue needs to cure doesn't it! But not feeling bad on time. Now watch I'll get flamboozled somehow.

Fred
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Old Mar 16, 2012, 04:44 PM
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Quote:
Originally Posted by cracksmeup View Post
Iam sighned up for another one Freddie ,iam in the repairing mode of my fleet ( mostly hanger rash )and not building for a while. joe
Hi Joe!

I love/hate the repairing mode of the fleet! I did that after the maiden session on the Raven if you recall. Still need to touch up that yellow paint on the SUV! LOL, the car isn't that important, the plane was!

Glad you are on board with another. It keeps the ice melted when someone chimes in. It feels pretty cold when you wonder if anyone noticed. LOL.

Day one building is now posted. But now day two was wasted posting! Oh well I can always use little breaks, so I'll see if I can get anymore done before the family gets back from shopping. Fish Fry tonight at the Church!

Fred
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Last edited by Freddie B; Mar 16, 2012 at 04:45 PM. Reason: There is a reason I had issues in spelling class.
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