HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 11, 2009, 02:50 PM
I fly Army UAVs!
Kwesdog's Avatar
West Saint Paul, MN
Joined Aug 2002
566 Posts
Thats what I said on the UCAV post. I think this airframe must be more C.G. friendly than the UCAV is.

Getting that UCAV down to 6.6 lbs and inside of the CG range with out modding it would be tough.

Doesnt look like this airframe will have that problem. Is there much room to move the batteries around in this one?

Harry
Kwesdog is offline Find More Posts by Kwesdog
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 11, 2009, 03:02 PM
Registered User
United States, FL, Tampa
Joined May 2001
221 Posts
I've been eyeing this airframe since it appeared on Nitro's site and have just been waiting for someone here with more EDF experience than I to give it a shot first! I'm anxiously waiting a flight report Jim and many thanks for posting what you have so far!!!
shv2sail is offline Find More Posts by shv2sail
Reply With Quote
Old Feb 11, 2009, 03:31 PM
I'm a lead farmer Mother ^%$^%
Sniper.308's Avatar
Lakeland, Fl.
Joined Apr 2007
444 Posts
Just about finished with mine.Waiting on a new balanced 96mm rotor from Himaxx.
Did yours have the rear carbon rod hole already punced or did you drill it. How did you attach your wings, there are no wing bolts?
Planning on running mine on 6,7, and 8S 3500mah and ARC 3675 1T motor.
Sniper.308 is offline Find More Posts by Sniper.308
Reply With Quote
Old Feb 11, 2009, 08:06 PM
Registered User
Joined May 2006
8,108 Posts
Seems like the fan would benefit from an intake ring since there is no ducting?
Socomon is offline Find More Posts by Socomon
Reply With Quote
Old Feb 11, 2009, 09:09 PM
United States, GA, Columbus
Joined Mar 2002
1,123 Posts
Quote:
Originally Posted by Socomon
Seems like the fan would benefit from an intake ring since there is no ducting?
I agree, there was an intake ring included with the fan but was too large and did not fit in the given space. I suppose I could have dremeled a spot for it.
May try it later.

James
JIMinKENTUCKY is offline Find More Posts by JIMinKENTUCKY
Reply With Quote
Old Feb 11, 2009, 09:15 PM
United States, GA, Columbus
Joined Mar 2002
1,123 Posts
Quote:
Originally Posted by Sniper.308
Just about finished with mine.Waiting on a new balanced 96mm rotor from Himaxx.
Did yours have the rear carbon rod hole already punced or did you drill it. How did you attach your wings, there are no wing bolts?
Planning on running mine on 6,7, and 8S 3500mah and ARC 3675 1T motor.
I did drill the hole as marked for the carbon rod.
I attached the wings with 2-3/4" screws with washers. One screw per wing. I wanted 2 per wing (one in front and one in rear) but could not reach to put one in the rear.

I tested it and is very sturdy. You could put just a touch of epoxy at the rear to be safe.

James
JIMinKENTUCKY is offline Find More Posts by JIMinKENTUCKY
Last edited by JIMinKENTUCKY; Feb 11, 2009 at 09:23 PM.
Reply With Quote
Old Feb 11, 2009, 09:29 PM
United States, GA, Columbus
Joined Mar 2002
1,123 Posts
Center of Gravity problem.

The text in the manual states 90mm (3.5") behind leading edge but the illustration shows it 50mm back from leading edge.

I'm thinking the diagram showing 50mm back might be the correct one but not sure.

I was wanting to maiden soon but not knowing the CoG doesn't help any.

James
JIMinKENTUCKY is offline Find More Posts by JIMinKENTUCKY
Last edited by JIMinKENTUCKY; Feb 11, 2009 at 11:20 PM.
Reply With Quote
Old Feb 11, 2009, 09:37 PM
Electric Coolhunter
Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,474 Posts
Sure needs a bell mouth inlet lip....and a short tapered thrust tube.

A custom duct like the real Fantrainer has would work fine, with the proper bell mouth inlet lip and cross sectional shape. Otherwise, it really needs a nice nacelle added.

Running it on a fan housing alone is kinda crude.
Thomas B is offline Find More Posts by Thomas B
RCG Plus Member
Latest blog entry: 2014 events and travel
Reply With Quote
Old Feb 11, 2009, 09:42 PM
United States, GA, Columbus
Joined Mar 2002
1,123 Posts
Question about intake lip. Does it increase the thrust at a given amps/watts or does it increase thrust while increasing amps/watts.

What Im asking is say at 1200 watts would I get more thrust with an intake ring than at 1200 watts with no ring? If my question makes any sense.

Thanks,
James
JIMinKENTUCKY is offline Find More Posts by JIMinKENTUCKY
Last edited by JIMinKENTUCKY; Feb 11, 2009 at 09:47 PM.
Reply With Quote
Old Feb 12, 2009, 07:01 AM
Registered User
FlyBoyTha1's Avatar
The Greater Bay Area
Joined Sep 2008
3,868 Posts
Quote:
Originally Posted by JIMinKENTUCKY
Here are some pics of the fan trainer that I just completed today.
I am using the RTR Himax 96mm which is a perfect fit for this jet.
Quality and workmanship of the kit is excellent.
No complaints on the hardware included although I did add larger wheels as seen in pics for better handling on grass.

I dont have any numbers yet from the wattmeter but I did test the fan on a 4s 3700 pack and it runs smooth. I will be using a 6s 3500 or 6s 4000 pack for flight.

For servos, I am using 3 standard size for rudder, nosegear, and elevator.
I am using digital mini metal gear servos for ailerons to save some weight.

Turnigy 80 ESC
Castle Creations BEC
Futaba Fasst 7ch receiver

James
Are Those Standard Hitec Servo's Or Hs81 Or 82's Looks Good Thats My Next Build Video, My Contact At Nitro Planes Shipped It On Tuesday, Should Recieve It Today At Noon. I'll Be Starting A Build Video Tonite P.s. I Have Had Any Trouble With The CG Yet Long As It's Nose Heavy An Lean Forward As The CG States You Should Be Fine. Or You Can Wait For About 4 to 5 Days And I Should Be Done With Mines And Ready For The Maiden Flight.
FlyBoyTha1 is offline Find More Posts by FlyBoyTha1
Reply With Quote
Old Feb 12, 2009, 07:14 AM
Registered User
Joined May 2006
8,108 Posts
Quote:
Originally Posted by Thomas B
Sure needs a bell mouth inlet lip....and a short tapered thrust tube.
I don't see how you would do the thrust tube. Any ideas?

Edit - I guess the tube could be cut into halves and mounted along each side of the fuselage. That is the only way I can see.
Socomon is offline Find More Posts by Socomon
Last edited by Socomon; Feb 12, 2009 at 07:20 AM.
Reply With Quote
Old Feb 12, 2009, 08:10 AM
United States, GA, Columbus
Joined Mar 2002
1,123 Posts
Quote:
Originally Posted by FlyBoyTha1
Are Those Standard Hitec Servo's Or Hs81 Or 82's Looks Good Thats My Next Build Video, My Contact At Nitro Planes Shipped It On Tuesday, Should Recieve It Today At Noon. I'll Be Starting A Build Video Tonite P.s. I Have Had Any Trouble With The CG Yet Long As It's Nose Heavy An Lean Forward As The CG States You Should Be Fine. Or You Can Wait For About 4 to 5 Days And I Should Be Done With Mines And Ready For The Maiden Flight.
Rudder: Hitec HS-475HB (the lightest standard servo I could find)http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDEM1
Elevator: Hitec HS-5475HB Digital Standard Karbonite http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDEM3
Nosegear: Standard Size Scanner RC MG
Ailerons: HD-2216MG http://www.hobbycity.com/hobbycity/s...g/2.2kg/.09sec

As for CoG, I dont know what it is.
The manual shows both 50mm from leading edge and 90mm. A difference of about 1.6 inches.

James
JIMinKENTUCKY is offline Find More Posts by JIMinKENTUCKY
Last edited by JIMinKENTUCKY; Feb 12, 2009 at 08:15 AM.
Reply With Quote
Old Feb 12, 2009, 09:26 AM
I'm a lead farmer Mother ^%$^%
Sniper.308's Avatar
Lakeland, Fl.
Joined Apr 2007
444 Posts
Quote:
Originally Posted by JIMinKENTUCKY
I did drill the hole as marked for the carbon rod.
I attached the wings with 2-3/4" screws with washers. One screw per wing. I wanted 2 per wing (one in front and one in rear) but could not reach to put one in the rear.

I tested it and is very sturdy. You could put just a touch of epoxy at the rear to be safe.

James
Oh, ok I get it. I will do that but a little different. I'll put a blind nut in the wing where you have your screw and use a bolt and crush washer inside the fuse. My maiden flight will be at useing 6S on a 1680kV ARC motor to keep it light and find the CoG. Thena I'm going all out on 9S. There is so much room in the fuse for batt's it should be interesting. Hopefully dave from Lightflight gets his 75mm motors in soon. I really want to try a 1000-1150 motor on 12S with this fan. I will also be trying to do a sectioned lip on this fan. You will have to end the lip on the top outside rim as to no cut off the already small intake FSA. Also the intake on the nose needs to be there and has multiple benifits. More air for the fan, cooling of electronics, etc.
Sniper.308 is offline Find More Posts by Sniper.308
Reply With Quote
Old Feb 12, 2009, 11:50 AM
Electric Coolhunter
Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,474 Posts
Quote:
Originally Posted by Socomon
I don't see how you would do the thrust tube. Any ideas?

Edit - I guess the tube could be cut into halves and mounted along each side of the fuselage. That is the only way I can see.
Even a very short thrust tube to neck down the aft end of the fan would help...I think you could do one that is 1"-1.5" long
Thomas B is offline Find More Posts by Thomas B
RCG Plus Member
Last edited by Thomas B; Feb 12, 2009 at 12:01 PM.
Reply With Quote
Old Feb 12, 2009, 11:52 AM
Electric Coolhunter
Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,474 Posts
Quote:
Originally Posted by JIMinKENTUCKY
Question about intake lip. Does it increase the thrust at a given amps/watts or does it increase thrust while increasing amps/watts.

What Im asking is say at 1200 watts would I get more thrust with an intake ring than at 1200 watts with no ring? If my question makes any sense.

Thanks,
James
As I recall, I think you will see a thrust increase and an amp draw decrease with a proper inlet lip. Also, without the lip, the fan will be prone to cavitation at moderate angles of attack, due to the sharp lip of the bare fan housing. If you do some searching around here, you will see the results of inlet lip tests.

The benefits of the inlet lip were described in one of your previous threads by seeveral people:

http://www.rcgroups.com/forums/showt...ight=inlet+lip

Adding a short thurst tube with a smaller exit area will increase efflux and also slightly increase amp draw.
Thomas B is offline Find More Posts by Thomas B
RCG Plus Member
Last edited by Thomas B; Feb 12, 2009 at 12:01 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Cool pictures of fan flying off EDF-50 unit. hsuusa Parkflyers 1 Jul 08, 2002 03:43 AM
Fan-fold foam EDF Vincent Electric Ducted Fan Jet Talk 8 Jun 19, 2002 06:20 PM
My new jet trainer for EDF 300 kwan Electric Ducted Fan Jet Talk 3 Jun 26, 2001 06:54 AM
Where's the Fan Trainer by Steve Neil? rcdude Electric Ducted Fan Jet Talk 11 Jun 06, 2001 02:42 AM