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Old Jul 02, 2012, 09:11 AM
Voltage is LiFe
novastar's Avatar
US East Coast
Joined Aug 2007
638 Posts
RadJet on 4S

Well, due to the retirement of my old FunJet, I have been "fun"Jet less. I have a Stryker F-27Q, but it is just not the same for me. I saw the RadJet 420 and knew I had to have it.

Flew it on the stock 2S... Pretty good, not good enough for me. Using the stock ESC, receiver (Orange), motor and prop, I wired in series 3 Thunder Power 160 mAh 1S batteries and made a flight test. Much better! I made sure that my static Amp draw was not more than 4 Amps. I have several flights on this with good results. I make sure not to hold WOT for more than 6-8 seconds at a time. The stock motor can get hot, but with throttle management, it seems to be handling it fine (no scoring on the motor coils whatsoever).

...But this was not good enough for me. I spent a good part of yesterday taking the plane apart, soldering in a Castle Creations Thunderbird 6 Amp ESC, while trimming down the stock prop, until my Amp draw did not exceed 4.16 Amps or so at WOT on a charged...4S pack! I briefly tried this on the stock ESC and it armed and rang out all 4 cells, however, the servos started to freeze and lock up. The 4S pack consists of 4 Thunder Power 1S 160s' wired together in series.

I made a maiden flight with it last night...WOW! I do not own a doppler, but my flying buddy and I (along with two other spectators were throughly impressed with it). It is FAST and smooth! I put her into a vertical climb, and she kept going and going and going, until I chopped the throttle. This is what it should have been. I know that I am "red-lining" most of the components in it, so I run the real risk of burning something out, but until that happens, it is a total adrenaline rush!
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Old Jul 05, 2012, 09:40 PM
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planekrazy's Avatar
Redwood City, CA USA
Joined Mar 2002
495 Posts
Congrats on the 4S flights, sounds fun I guess with lots of throttle management the AP05 stock motor is working for you, hopefully it will last long time. The BL1230-4200kv motor on 3S has been working well running WOT for 10 flights or so now. Ordered a Turnigy 1230-4500kv motor to experiment with next in case the 4200kv develops issues. For now planning to stick with 3S here, although recently upgraded to a 4S setup on my Critical Mass micro racer. Wish HK would come out with small 4S packs already, the one I've been using so far was built by soldering 2 nanotech 180mAh 2S packs in series.
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Old Jul 06, 2012, 01:26 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
Have you guys run the FunFighter Micro warbirds yet?
They're 4s ready out of the box and darn quick.
There's a Rare Bear you might like.
Check out some of the videos, they are really fast.
http://www.hobbyking.com/hobbyking/s...dProduct=18477

BH has the T45 for $59.
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Old Jul 06, 2012, 10:19 AM
Can we lift the embargo?
kenstogie's Avatar
menands flats, NY
Joined Dec 2006
1,632 Posts
I have a radjet 420 and it's been sitting in the box for 3 months or soo. It seems that my elevons move differently. By that I mean the right one moves less than the left. So it just sits there. Both go up when I pull back on the stick and they move the correct way just at different amounts.

Did I set up my DX6i incorrectly?

Is it a bad servo?

I would like to fly this eventually. LOL
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Old Jul 06, 2012, 10:36 AM
Registered User
Austria
Joined Jan 2004
8,069 Posts
Quote:
Originally Posted by kenstogie View Post
I have a radjet 420 and it's been sitting in the box for 3 months or soo. It seems that my elevons move differently. By that I mean the right one moves less than the left. So it just sits there. Both go up when I pull back on the stick and they move the correct way just at different amounts.

Did I set up my DX6i incorrectly?

Is it a bad servo?

I would like to fly this eventually. LOL
Probably you have wrong center or wrong end point in the tx configuration
Easy to fix on a decent tx

Tchuss

E_lm_70
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Old Jul 06, 2012, 10:43 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
ken,
The DX6i has a programming bug in elevon mode.
Do this and let's see what you get.

http://www.rcgroups.com/forums/showp...2&postcount=35
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Old Jul 06, 2012, 04:50 PM
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planekrazy's Avatar
Redwood City, CA USA
Joined Mar 2002
495 Posts
Quote:
Originally Posted by IFlyRCs View Post
Have you guys run the FunFighter Micro warbirds yet?
They're 4s ready out of the box and darn quick.
There's a Rare Bear you might like.
Check out some of the videos, they are really fast.
http://www.hobbyking.com/hobbyking/s...dProduct=18477

BH has the T45 for $59.
Yes several of us at the field have the 620mm Rare Bears (and other funfighters) and we enjoy flying them. There's a video on my YT channel with a few of us play racing them WOT on 4S, that is always a kick and never gets old. Be careful though the stock ESC will/will not handle WOT with 4S depending on the prop used.

That said, there's just something about these cute little micro planes going fast that has always hooked me. These newer HK/Durafly 400-490 micros build and fly better than the older Cox micro warbirds that we used to fly years ago. Been experimenting with the little RearBear, CriticalMass, this 420 jet and soon the Edge 540, so could say that I am hooked again
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Old Jul 07, 2012, 12:05 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
Tell me a little about the Critical, I haven't seen anything reported on it yet.
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Old Jul 07, 2012, 01:01 AM
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planekrazy's Avatar
Redwood City, CA USA
Joined Mar 2002
495 Posts
Quote:
Originally Posted by IFlyRCs View Post
Tell me a little about the Critical, I haven't seen anything reported on it yet.
There is some info and videos on the Durafly 440mm Critical Mass and 400mm Rear Bear micros in the below thread:
http://www.rcgroups.com/forums/showt...535744&page=10

My thoughts on the Critical Mass start in post #138 of the above thread in case you are interested.
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Old Jul 07, 2012, 02:18 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
Well, I guess I'm out on the CM.
The horns and rods do not look belly landing friendly.

Thanks for the info.
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Old Jul 07, 2012, 09:55 PM
Voltage is LiFe
novastar's Avatar
US East Coast
Joined Aug 2007
638 Posts
Congrats on the 4S flights, sounds fun I guess with lots of throttle management the AP05 stock motor is working for you, hopefully it will last long time. The BL1230-4200kv motor on 3S has been working well running WOT for 10 flights or so now. Ordered a Turnigy 1230-4500kv motor to experiment with next in case the 4200kv develops issues. For now planning to stick with 3S here, although recently upgraded to a 4S setup on my Critical Mass micro racer. Wish HK would come out with small 4S packs already, the one I've been using so far was built by soldering 2 nanotech 180mAh 2S packs in series.

Thanks! Again, I hold WOT for no more than 10 seconds at a time. In honesty, on 4S, 6-7 seconds at WOT can send me completely out of the park that I fly at, and that park is fairly large in size. Next time I fly, I want to try a full, 10 second WOT vertical climb with it to see how high it goes. I put in the Thunder bird ESC, since it can handle a maximum of 15 Volts. Granted, I am running at about 1.50 Volts more than this on a fresh 4S pack. The only thing that really worries me is the receiver failing in flight, or one of those micro servos. The Orange micro receiver has an input Voltage of up to 9 Volts I believe. I am afraid if it overheats or malfunctions in flight, things could get somewhat dangerous, due to the speeds involved. I might put in a micro Horizon receiver or place a resistor in its path to produce a Voltage drop. The only problem with that, though, is that I also want to fly on 3S, too.

In case anyone is interested, the prop I am using is a completely stock one, but trimmed down to 2 and 8/16 of an inch (2.50 inches) for the 4S setup. I use the stock motor, with no modifications whatsoever. Tonight I trimmed down the vertical stabilizers a bit, to reduce drag somewhat, however, I am not going to touch the wings. Unless a component burns out, this is about as light and powerful as I know how to make it. I am taking the Thunder Power 160's, statically, to their maximum C rating. With throttle management, they come down warm, NOT hot. These 160s pack as much wallop per gram in any micro Li-Po that I am aware of. Four of them in series, make the plane scream. The small little prop does not produce as much instant acceleration as a larger (stock) one does, so it does take about 2 seconds or so to get going fast, but once that time period is over, the plane really steps into gear. Using various wiring harnesses, I can fly my RadJet in the following configurations: 2S, 3S or 4S, using simple, ubiquitous, 1S UM-style batteries.

More to follow...

Cheers,
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Last edited by novastar; Jul 07, 2012 at 10:10 PM.
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Old Jul 07, 2012, 10:19 PM
Voltage is LiFe
novastar's Avatar
US East Coast
Joined Aug 2007
638 Posts
Quote:
Originally Posted by kenstogie View Post
I have a radjet 420 and it's been sitting in the box for 3 months or soo. It seems that my elevons move differently. By that I mean the right one moves less than the left. So it just sits there. Both go up when I pull back on the stick and they move the correct way just at different amounts.

Did I set up my DX6i incorrectly?

Is it a bad servo?

I would like to fly this eventually. LOL

Mine does the same. I also have a DX6i from Spektrum. My RadJet came from the factory with its left elevon servo's arm one 'click' more forward than the right one. I had to carefully pull that servo out of the plane's wing, unscrew the arm, center it, adjust the links, and subtrim it back into place. I notice when I do not use full aileron throw, and at certain speeds, the plane will roll like a drill bit, which is very desirable, however, it will corkscrew at other times. I am using the built-in elevon function, within the transmitter, and am not using a composite mix to simulate it, though, I might try that out for this model.
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Old Jul 10, 2012, 02:00 PM
Can we lift the embargo?
kenstogie's Avatar
menands flats, NY
Joined Dec 2006
1,632 Posts
Thanks Guys, I will try these things and tell you what I've found.
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Old Jul 12, 2012, 09:55 AM
Registered User
Austria
Joined Jan 2004
8,069 Posts
Quote:
Originally Posted by e_lm_70 View Post
Just order (back order unluckily) the RadJet 420 ... but I will make it from parts this save lot of money in shipping and also in the bird itself.

I also got some buddy code in case you need some spare or you want to build one from scratch:


Radjet 420 - Replacement Fuselage w/ Motor Mount Save US$: 2.06


Radjet 420 - Replacement Main Wing Set Save US$: 1.33


Radjet 420 - Replacement Vertical Stabilizer Save US$: 0.61



Radjet 420 - Replacement Canopy Save US$: 0.32


Tchuss

e_lm_70
All parts are on stock now ...

So ...you have no more excuses for not saving money

Tchuss

e_lm_70
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Old Jul 24, 2012, 04:15 AM
Searching Field
DOCFIGHT's Avatar
Joined Oct 2011
64 Posts
Radjet 420, such an amazing micro-wing !
Check this vid of our speed battle : Radjet 420 vs. Micro Stryker 180

http://www.matterhorns.org/pages/vid...sion-2012.html

Have Fun & Fly. Over.
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