HobbyKing.com New Products Flash Sale
Closed Thread
Thread Tools
Old Jun 22, 2011, 07:33 AM
Registered User
Joined Feb 2006
2,396 Posts
Discussion
I cant believe I actually did it 120mm EDF

I am ready to maiden my T-45 hawk 120mm EDF jet. Here are the specs, Going to try it first on 10s with HET 120mm 935kv motor. Castle 120hv speed controller with a very balanced change sun fan. Going to bungee launch it just like the white CMP T-45 hawk. The kit was a pain in the rear end to build because it was designed to be used by os.91 nitro engine. The elevators were a pain to put on with the supplied linkage. I am hoping 10s will be enough power, I dont want to spend couple hundred on batteries right now incase I get a mishap so I think 10s should be good. YES I willl have video for everyone to see. I wanted to sell the kit but I could never get that much for it so I decided to build it. I got ripped off, I traded my 150mph plus funjet for this kit which I had almost $400 dollars in. Oh well, lets hope this flys

I was reading another post about the edf fan exploding and causing damage to the members eye. I was like wow that is pure bad luck and how serious kind of power these fans generate. I was just thinking that could of been me with my lack of knowlege crazy builds and test stations. This time I tested it outside and was happy at full throttle the fan did not come out of the housing
sherlockshah is offline Find More Posts by sherlockshah
Sign up now
to remove ads between posts
Old Jun 22, 2011, 11:19 PM
Lee Liddle
Knife Liddle's Avatar
Carrollton, Tx
Joined Dec 2006
8,216 Posts
Good luck Sherlock. Make sure and put plenty of tention on the bungee. Five 5 times the weight of the model is the rule of thumb. Make sure the stake is a strong one too.
Knife Liddle is online now Find More Posts by Knife Liddle
RCG Plus Member
Old Jun 22, 2011, 11:26 PM
Registered User
Joined Apr 2004
799 Posts
Hi

With such a large model, why no gear. Just for info, I have a BVM F-16 I put a dynemax in, scale gear,doors, brakes, LE edge flaps, flaperons, 12s (6s x2) 5300ea. Around 16lbs.

Good power, but still adjusting tail cone dia.

Steve
SCALECRAFT is offline Find More Posts by SCALECRAFT
Old Jun 22, 2011, 11:36 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
20,951 Posts
pics? what 120mm hawk is it ?
AIR SALLY is online now Find More Posts by AIR SALLY
Old Jun 22, 2011, 11:39 PM
DELTAS RULE
corsair nut's Avatar
tehachapi, CA
Joined Jan 2006
22,444 Posts
jhh copy.

better have some serious bungee pull.

how much does it weigh? that is a tip stalling mofo.....dont trust the manuals cg.

watch the slow speed turns......this model has a wicked tip stall.
corsair nut is offline Find More Posts by corsair nut
Old Jun 23, 2011, 03:04 AM
Aka: Tom Jenkins
ApexAero's Avatar
Palm Beach County, Fl.
Joined Aug 2008
4,490 Posts
Its probably all over but the crying by now.
ApexAero is online now Find More Posts by ApexAero
Old Jun 23, 2011, 09:20 AM
Registered User
Joined Feb 2006
2,396 Posts
I asked earlier but no one gave me an answer

The CG says 127mm or 5inch from the front of the wing. I remember on my white one the CG was 90-95mm and flew great. On the white one the CG was on the two humps on top, here 5inch comes out inch and half behind the humps. I am going to make it nose heavy and not follow the manual just incase. 120mm edf is way way different in power band. I did not think there would be that much difference between the 90mm and the 120mm since its only 30mm difference but man its intense. Weight is I would say under 9 pounds. I dont have flaps or landing gear and using only 4000mah packs. The power is almost 1 to 1 on 10s. I know it wont be a speed demon but I learned from the last white one I built that mpope ran over 110mph on 6s and mine was closer to high 120's or low 130's but with 4 extra cell. So on 10s I would get a much higher flight time, I am sure the performance would be great on 12s but I dont think the mph would be much higher. I am new at this so lets see how it goes. I will have a video of it
sherlockshah is offline Find More Posts by sherlockshah
Old Jun 23, 2011, 09:22 AM
Registered User
Joined Feb 2006
2,396 Posts
we dont have a runway, this is funny

Quote:
Originally Posted by SCALECRAFT View Post
Hi

With such a large model, why no gear. Just for info, I have a BVM F-16 I put a dynemax in, scale gear,doors, brakes, LE edge flaps, flaperons, 12s (6s x2) 5300ea. Around 16lbs.

Good power, but still adjusting tail cone dia.

Steve
I hated before the idea of bungee and was known to crash everything trying to hand launch but now that I am good at it, I bungee everything. I bungee the funjet , I bungee even the big honda jet with the twin prop motors, I bungee the white T-45 which everyone here has seen the video, now its time to bungee this big 120mm edf.
sherlockshah is offline Find More Posts by sherlockshah
Old Jun 23, 2011, 09:30 AM
Registered User
LuvEvolution7's Avatar
St.Catharines, Ontario
Joined Jan 2009
10,377 Posts
I'de put electric retracts on it and have done with it. I've bungee'd and belly landed my fair share of planes over the years, but it aint as much fun as using wheels. for the extra few ounces of weight you are going to add, it's kinda crazy not to add them. also, if this plane tip stalls as bad as CN says it does, you want some safety margin that landing gear can supply. the problem with a bungee is inconsistancy. you cannot predict the launch speed at the end of a pull, since it's different every time. you are more prone to tip stall here than anywhere else. at least with gear, you can allow the plane to accelerate untill you feel it's ready to lift off. with a bungee, you have no control of this and it's a crap shoot, especially if you don't have enough pull to begin with.

I believe that when you get bigger than 90mm, you should be forgetting the bungee anyway. unless you are entering a specially designed plane in a speed contest, there's no reason to put your plane at risk. just my two cents of course.

Rich
LuvEvolution7 is offline Find More Posts by LuvEvolution7
Old Jun 23, 2011, 09:32 AM
There was a crease in the plan
Steve Haynes's Avatar
Joined Jun 2010
1,332 Posts
Having gear means you can use flaps.
Steve Haynes is offline Find More Posts by Steve Haynes
Old Jun 23, 2011, 09:35 AM
Registered User
jefffassbinder's Avatar
United States, CA, Chino Hills
Joined Jan 2011
1,223 Posts
Cg

Do yourself a favor, I've had a AMD and another of the Wilson or whatever knockoff BAE's the 5" when they were writing the manuals 15 years ago were thinking glow and in the 12 oz and 6 or 8oz secondary fuel tank in the front. So I'd stick with the 5" CG location otherwise your tail is going to be very ineffective at the time of landing. Make sure you have lots of speed on take off. People used to tell me I was going to fast and I should rotate sooner but you need the speed. Flaps on this BAE AMD or whatever knockoff blanket the elevator and make for a very ineffective elevator(stab). If this is the 120mm version you need a very high torque servo in the tail. Flaps after 15 degrees hurt the pitch authority.

Good luck, I did have a lot of fun with this model.

Things I would do differently now after playing with edf for a while is movethe fan unit aft near the wing bolts at the trailing edge. Make or have made a intake extension so that battery placement could be easier and CG would be more easily achieved.
jefffassbinder is offline Find More Posts by jefffassbinder
RCG Plus Member
Old Jun 23, 2011, 09:49 AM
Registered User
Joined Feb 2006
2,396 Posts
Thank you so much I was really worried about the CG

Quote:
Originally Posted by jefffassbinder View Post
Do yourself a favor, I've had a AMD and another of the Wilson or whatever knockoff BAE's the 5" when they were writing the manuals 15 years ago were thinking glow and in the 12 oz and 6 or 8oz secondary fuel tank in the front. So I'd stick with the 5" CG location otherwise your tail is going to be very ineffective at the time of landing. Make sure you have lots of speed on take off. People used to tell me I was going to fast and I should rotate sooner but you need the speed. Flaps on this BAE AMD or whatever knockoff blanket the elevator and make for a very ineffective elevator(stab). If this is the 120mm version you need a very high torque servo in the tail. Flaps after 15 degrees hurt the pitch authority.

Good luck, I did have a lot of fun with this model.

Things I would do differently now after playing with edf for a while is movethe fan unit aft near the wing bolts at the trailing edge. Make or have made a intake extension so that battery placement could be easier and CG would be more easily achieved.
I have the fan mounted right in the front pretty much dead on with the cg. I taped the flaps shut since I will be belly landing. I am using a high torque digital servo for the tail ( real pain in the rear end the mechanics of it ERRRR) WIth my set up I did not have to move the fan toward the rear. I am using xps 10s 4000mah 65c packs. With the current kv of 935 its not at top peformance but I think it should still fly decent. I will be using a 16 foot bungee ramp. I used this ramp on my heavy honda jet and worked perfect. I could not spool up the motors until it cleared the ramp and had lift because the props were hitting the bungee ramp. SO i know my bungee system has plenty of power to shoot this jet which actually weighs less than my honda jet. I wish someone could explain the whole power band with the kv's. I go full throttle on this one on 10s and seems it has plenty of power but it really needs 12s to get going, by me having two cells less its about 7500rpm less not sure if that is huge amount of power loss?
sherlockshah is offline Find More Posts by sherlockshah
Old Jun 23, 2011, 09:54 AM
Registered User
Joined Feb 2006
2,396 Posts
here is the video of the exact one I have but electric

http://www.rcgroups.com/forums/showthread.php?t=1455621
sherlockshah is offline Find More Posts by sherlockshah
Old Jun 23, 2011, 09:55 AM
Registered User
Joined Feb 2006
2,396 Posts
Mine is red white and blue color

This one is all red.
sherlockshah is offline Find More Posts by sherlockshah
Old Jun 23, 2011, 09:58 AM
Registered User
LuvEvolution7's Avatar
St.Catharines, Ontario
Joined Jan 2009
10,377 Posts
ala Red Arrows. do you have the white Arrow painted on the underside, or solid red?
LuvEvolution7 is offline Find More Posts by LuvEvolution7
Closed Thread


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Advanced Scale Models (ASM) 72" 120MM Mig-15 EDF FlyBoyTha1 Electric Ducted Fan Jet Talk 192 Dec 22, 2011 11:24 PM
Discussion I can't believe he did this dll932 Life, The Universe, and Politics 11 May 23, 2011 12:54 PM
Whoops! I can't believe I did this... IBCrazy FPV Talk 32 Mar 22, 2011 05:02 AM
Yippee! I Can't believe I Did It But I Did Mashem Marv Electric Heli Talk 33 Mar 05, 2007 09:49 AM