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Old Jun 17, 2010, 06:09 PM
EDF rules... :)
AirX's Avatar
Joined Nov 1999
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Pdawg,

Nice work, what fan/motor combination are you looking at using?

Eric B.
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Old Jun 17, 2010, 07:40 PM
Team30 Micro EDF
NitroCharged's Avatar
Adelaide, Australia
Joined Apr 2004
11,196 Posts
Steve C, what is this turbulator stuff you speak of? e.g how would it be setup in the intakes etc.
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Old Jun 17, 2010, 07:52 PM
Current project: Electrolyte
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United States, OH, Dayton
Joined Apr 2004
5,480 Posts
AirX,

This airframe was scaled to handle both 30-40mm fans. I am fortunate to have a 30mm power system made by Nitrocharged and one built by Mcross. I know these are custom systems but I also plan to test some other readily available systems like the 40mm fan setups with 12mm & 20mm motors.
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Last edited by pdawg; Jun 17, 2010 at 11:25 PM.
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Old Jun 17, 2010, 10:58 PM
Addicted to building...
Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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Quote:
Originally Posted by NitroCharged View Post
Steve C, what is this turbulator stuff you speak of? e.g how would it be setup in the intakes etc.
I would like to know too.

Saw what I think was some tubulators inside the ducting off a full scale F-111 once, but they seemed to be placed quite random as if fitted specific to each intake, almost like they were used similar to balancing a rotor, shaft, flywheel, etc. These were basiclly little vanes stood on end, sort of like little wings, around 6 inches tall by 2.5 inches wide, halfway down where the ducting curved, maybe 10-12 per duct, more congregated near the 1 and 2 o'clock position, others around 4:30-5 o'clock (inboard). Seeing this has always intrigued my curiosity???????????

Fred
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Old Jun 18, 2010, 08:53 AM
Carbon fiber is our friend
Steve C's Avatar
United States, CA, Lodi
Joined Feb 2001
4,207 Posts
I just saw that pic recently of the F-111. I had no idea there were any real jets with those inside! That probably means they screwed up when they designed it.

On mine, I have a very divergent duct with roughly 50% FSA. Well I know that airfoils that have too much curve or flying at low reynolds number can be helped by turbulators, so I decided to try something inside the inlet of my F-86. They were just thin pieces that looked like half a guitar pick except smaller (actually you could use that for material! ) I had 4 of them inside and I put a little angle on them.

Now I'm not absolutely positive about what would work best or even that this is what caused the performance leap, but I do know that the one time I flew with these pieces inside, it went 140 mph and climbed like crazy. At least I am certian that they didn't hurt because this was far beyond the performance of the plane in previous years.

Unfortunately it was a rare time that I flew using the BEC to power the radio and it crashed when I over taxed the battery. Another is under slow construction, but I thought I'd share this little tidbit since it might be a while before I find out for sure what's going on.

Steve C
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Old Jun 18, 2010, 09:16 PM
Current project: Electrolyte
pdawg's Avatar
United States, OH, Dayton
Joined Apr 2004
5,480 Posts
Fiberglassing with thin CA

Ok, well I've started the glassing of the Electrolyte but I thought I'd share why I choose to tackle this project now. I'm from Los Angeles where I have a workshop with plenty of room and tools to build. Currently however I'm in New York city (for school) with almost no room or tools. I was losing my mind not being able to build so I decided on this doable project. Making the Electrolyte plug has required a small space and a minimal amount of tools. I don't even have a dremel here to work with. Some 120, 220,& 320 grit sandpaper has done the job though. I go home early next month and my goal it to have the plug complete so I can get right to the molding process for the 2 weeks I'm home.

Back to the construction, I took a few pics of the glassing technique with CA. I've used this numerous times on other projects with great success. Its faster, than using epoxy, is pretty easy, and importantly (for me in an apt.)doesn't create much of a mess. So far the Electrolyte is glassed from the intake to the tail.
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Old Jun 18, 2010, 09:25 PM
EDF rules... :)
AirX's Avatar
Joined Nov 1999
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Cool, thanks for the instructions on this technique.

Eric B.
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Old Jun 19, 2010, 12:55 AM
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Fresno California
Joined Jul 2009
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Subscribing to this wicked thread for sure. Nice work!
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Old Jun 19, 2010, 01:54 AM
Addicted to building...
Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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pdawg,

Terrific pictures and explination of your process. This is way cool. So much better than the usual final picture that leaves everyone wondering. Truely classic to pass info on to others. So much has been lost to history when talanted individuals passed on, taking their knowledge with them. Thank you from one of many!

Just a thought if it helps someone out.

I use the Walmart CA for some glassing jobs because it costs .97 cents for 4 tubes (or $1.00 in another department! Go figure). Never had an issue with it and it flows/sticks/dries just fine. Can't use it on foam so that is when I have to use the expensive stuff.

Fred
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Old Jun 19, 2010, 03:04 AM
Team30 Micro EDF
NitroCharged's Avatar
Adelaide, Australia
Joined Apr 2004
11,196 Posts
Nice stuff pdawg! I'll follow your work and do the same this end.

What's funny is your current kitchen bench/breakfast bar is still bigger than the work space on my desk. Oh the joys of micro jets - don't need much room to make 'em!


.
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Old Jun 19, 2010, 11:49 AM
Carbon fiber is our friend
Steve C's Avatar
United States, CA, Lodi
Joined Feb 2001
4,207 Posts
The plastic bag is a good idea. I usually just end up with a new hard skin on my finger.

Looking good.

Steve C
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Last edited by Steve C; Jun 20, 2010 at 11:52 AM.
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Old Jun 19, 2010, 02:07 PM
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Speedfreak's Avatar
Virginia Beach Va.
Joined Nov 2001
503 Posts
F-18s have these in the ducts as well, except we call them vortex generators. Same thing just a different name, they impart some spin to the air before it goes into the engine and they are very sharp!!!
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Old Jun 20, 2010, 02:19 AM
DELTAS RULE
corsair nut's Avatar
tehachapi, CA
Joined Jan 2006
21,853 Posts
ok...how the heck did i miss this bret!!!!!! SHWEEEET! when you coming back to CA? any time soon? is K&A going to pop these out for you too?
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Old Jun 20, 2010, 10:29 AM
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Sherlock's Avatar
Milwaukee, WI
Joined Sep 2006
357 Posts
They sell vortex generator kits for many general aviation planes. They produce a high energy vortex (like the vortex produced on the wingtips of planes) that helps the air stay attached to the surface at high angles of attack. You can get a lower stall speed/higher gross weights with them. Works the same way in an intake.

The tail on a piper Seminole could stall on landing before the wing would. Some had vortex generators on the underside of the horizontal tail to prevent this. It is a little disconcerting to have the yoke slam back to the stops and the nose drop while flaring!!
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Old Jun 20, 2010, 04:54 PM
Addicted to building...
Freddie B's Avatar
Omaha Nebraska
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Quote:
Originally Posted by Sherlock View Post
The tail on a piper Seminole could stall on landing before the wing would. Some had vortex generators on the underside of the horizontal tail to prevent this. It is a little disconcerting to have the yoke slam back to the stops and the nose drop while flaring!!
A little disconcerting? Especially when your little 'ol self is actually sitting in the plane? I'll say!

When I saw the vortex generators in that F-111 (parked in Nebraska), they seemed again to be placed sort of randomlly. Guessing some wind tunnel testing figured out where they should go.... Wonder if it was fine tuned from ship to ship, duct to duct? Seems like it might be as all aircraft are slightly different by the time all those tolerances add up!

Wish we had a way to figure out when they would help our small EDF models, where to place them, etc. Maybe this could be the next big performance boost needed at minimal cost!

Sorry pdawg, not meaning to waste any space on your great thread discussing this topic. See what you started! LOL! Anyway hope to see some more photos and progress soon! Love your design!

Fred
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