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Old Jul 24, 2006, 04:58 PM
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Matthew Allen's Avatar
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Could someone tell me approximately what the dimensions of the FJ's battery bay are? I'm looking into what's available and what's cheap.

Matthew
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Old Jul 24, 2006, 05:26 PM
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Bigplumbs's Avatar
Suffolk, In the UK
Joined May 2004
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Battery Bay Size

Quote:
Originally Posted by mcba
Could someone tell me approximately what the dimensions of the FJ's battery bay are? I'm looking into what's available and what's cheap.

Matthew

The battery bay is very spacious. I hope the attached photo's help

Dennis
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Old Jul 24, 2006, 05:28 PM
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Thanks Dennis, just what I needed.

Matthew
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Old Jul 24, 2006, 05:32 PM
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Suffolk, In the UK
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Quote:
Originally Posted by erashby
I like your fleet.
I run the same setup on my stryker, but with one more cell. (Mega 4T, Kontronic Smile 6-12-40, APC 6x4, and Tanic 2220 4S.) Your Motor and ESC will handle the extra cell, with some ventilation, and the increase in speed will be amazing. My Stryker is a porker at 30.3oz AUW (but I added CF spar, CF tape, Moded Motor mount, canoy and pilot, balsa hinged elevons, and UltraKote covering.) I estimate that it goes about 85MPH. That is just comparing it to other planes I've put my radar gun on. That day my Stryker had a weak soldier joint on the control rod, so I did not want to risk it.

I would put an extra cell on your Funjet and it will be bullistic.

As for the rest of your hanger, I've got the rest, just not the Funjet, yet .

My observations (not that anyone cares...)
The TJ looks the best, but its draw back is the need for two motors and two ESCs (unless you use the Kontronic), and a bit draggy airframe.

The Stryker foam is the most crash resistant but also less stiff and requires stuctural reinforcement for speed. The stubby nose and the rear sweep of the wing, and the flat canopy are drawbacks in the appearance (although I think mine is "looking good!").

The MJ looks good and has the stiff Elapor foam, but it is very week at the thin fuselage sides. It also has a totally symmetric airfoil, which means the only lift is from elevon reflex. It is way too heavy stock (high wing loading) but flies well at about 10 oz with a BL motor. I am carving an EPP nose for mine.

The Funjet looks great and would probably be the fastest at a reasonable wing loading. As soon as they are reasonably priced in the States, I'm sure to have one.

Note on motors: I have flown Kontronic Fun 400-23, and Mega 16/15/4T in the same airframe. They fly about the same. The Kontronic motor has an entire metal can and is precision made. It dissipates heat well, despite not having any ventilation holes. It does not cog, but rotates smoothly.(The brake does not hold the prop from turning.) It weighs 1 oz more than the Mega and costs about $50 more. My Funjet will probably get the Kontronic Fun 400-28, since new lipo battery packs with a higher discharge rate can now handle the higher amp draw.
If you are running a 4 cell pack with the mega 16/15/4 setup and with my Kontronik ESC don't you have to use a separate BEC rather than use the onboard one on the ESC.

I think I will try her on a APC 6 x 5.5e prop first as my lipos should be capable of around 33 amps.

I have to say however that the speed as I have her is not balistic but in my view quite a nice speed. I am in two minds and might keep her like this and build another with a mega 3 turn and up the servos a little to HS65's as I quite like sticking to 3 cell packs........................ As this bird is quite cheap I would quite like a second..............I still have 7 spare slots on my new transmitter so might as well fill them lol
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Old Jul 24, 2006, 06:15 PM
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Cleveland, OH
Joined Aug 2005
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Quote:
Originally Posted by erashby
Note on motors: I have flown Kontronic Fun 400-23, and Mega 16/15/4T in the same airframe. They fly about the same. The Kontronic motor has an entire metal can and is precision made. It dissipates heat well, despite not having any ventilation holes. It does not cog, but rotates smoothly.(The brake does not hold the prop from turning.) It weighs 1 oz more than the Mega and costs about $50 more. My Funjet will probably get the Kontronic Fun 400-28, since new lipo battery packs with a higher discharge rate can now handle the higher amp draw.
I'm not so sure about the statement that the 400-28 and the Mega 16/15/4 fly about the same. If you mean performance in the FJ than I would strongly disagree with you. I also have had both motors in the FJ with the same battery (TP21003S) and the same prop (CAM Speed 5.5 x 4.3) and I can say that the 400-28 takes the edge in the power department. See the static plots below. The first one is the Mega and the second one is the FUN. You decide which would be faster. The FUN 400-28 took me from the mid-70's mph to the low 90's.

I agree with you regarding the new breed of Lipo's. The battery is the only thing holding me back on propping up the FUN.
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Old Jul 24, 2006, 06:54 PM
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Aberystwyth, UK
Joined Sep 2004
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Quote:
Originally Posted by Bigplumbs
If you are running a 4 cell pack with the mega 16/15/4 setup and with my Kontronik ESC don't you have to use a separate BEC rather than use the onboard one on the ESC.

I think I will try her on a APC 6 x 5.5e prop first as my lipos should be capable of around 33 amps.

I have to say however that the speed as I have her is not balistic but in my view quite a nice speed. I am in two minds and might keep her like this and build another with a mega 3 turn and up the servos a little to HS65's as I quite like sticking to 3 cell packs........................ As this bird is quite cheap I would quite like a second..............I still have 7 spare slots on my new transmitter so might as well fill them lol
To replace the motor in a Funjet takes only 2 minutes max, thanks to a great design. Why buy another just to have a different motor.

Mark
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Old Jul 24, 2006, 08:15 PM
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Chula Vista,CA
Joined Jul 2004
111 Posts
Hey guys just found this thread. I'm an old Striker guy but this FunJet looks great.Has anyone tried a edf in one yet that you know of? Couldn't find anything on it. And were can i get one without waiting till October? And what is the price of them? Also is it the same kind of foam as the Striker?
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Last edited by AV8er48; Jul 24, 2006 at 08:28 PM.
Old Jul 24, 2006, 08:37 PM
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Vantasstic's Avatar
Las Vegas, NV
Joined Sep 2003
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AV8er, I don't have either the Stryker or the FunJet (yet). The Stryker is made of EPP if I recall right and the FunJet is Elapor. The EPP is more flexible/damage resistant than the Elapor, but the Elapor loves normal CA adhesives.
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Old Jul 24, 2006, 08:37 PM
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Aberystwyth, UK
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Quote:
Originally Posted by AV8er48
Hey guys just found this thread. I'm an old Striker guy but this FunJet looks great.Has anyone tried a edf in one yet that you know of? Couldn't find anything on it. And were can i get one without waiting till October? And what is the price of them? Also is it the same kind of foam as the Striker?

Try here http://www.rcgroups.com/forums/showt...&page=38&pp=15

I think there's a ducted fan Funjet in there on post 561.

Mark
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Old Jul 24, 2006, 11:45 PM
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Chula Vista,CA
Joined Jul 2004
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Thanks Mark.

Van yes the stryker is epp foam.



P.S Mark were did you get your FunJet at? Got a web site?
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Old Jul 25, 2006, 12:13 AM
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FoamCrusher's Avatar
Elk Grove, CA
Joined Sep 2002
4,176 Posts
RE: Mega vs. Fun 400-23 and other motors.

As I understand the numbering of the Kontronic, the 23 represents the Kv of the motor so it should have Kv= 2300. The two should be about the same if, the efficiencies are close. Individual current measurements are very dependent upon the prop used (make and balance), the length of the wires and the ESC used, so to say one is better than the others would difficult without doing some standardized testing. Cost is a pretty good rough measure however - better efficiency comes mostly from better magnets and more copper wire, both of which cost more money.

I looked up the Kv's of each of the motors being discussed as options. The Kv's are as follows:

Mega /4 = 2200
Mega /3 = 3000

Fun 400-23 = 2300
Fun 400-28 = 2800

Warp4 4-15-3 = 2580
Warp4 4-15-4 = 1810

Medusa Research 028-40-25 = 2500

I just returned from two weeks vacation and found my new FJ waiting for me (THANKS Jeremy and Stringfly!!!!) I am going to start with the Mega/4 on a CC35 and 3S1P 2100 TP-PL on and APC 6x4e prop as that is a well proven system in my Stryker and several other planes. Heat is an issue for me here (it was 111F today) so I can't get too carried away with all out power until Fall arrives!

Once I get it dialed in I am going to switch to the Medusa and see if 300 more Kv makes a noticeable difference. The Medusa is slight heavier than the Mega and if it is not that much faster, I have a warbird that needs some more weight in the nose that should take the Medusa nicely.

Higher Kv motors are nice, but I would have to go up in cell size to not cook them and I have too much invested in 2100 mAh packs to start changing now. Speed costs $ and more speed costs cubic $.... and I am happy with just reasonably fast.

FC
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Last edited by FoamCrusher; Jul 25, 2006 at 11:46 PM.
Old Jul 25, 2006, 02:02 AM
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Bigplumbs's Avatar
Suffolk, In the UK
Joined May 2004
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Quote:
Originally Posted by MarkJayne
To replace the motor in a Funjet takes only 2 minutes max, thanks to a great design. Why buy another just to have a different motor.

Mark
I agree changing the motor only takes a short while on this plane but I have the urge for a second one and as they say two is better than one

Anyone got an answer to using the onboard BEC with a 4 cell pack ?

www.densplanes.co.uk
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Old Jul 25, 2006, 04:00 AM
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Aberystwyth, UK
Joined Sep 2004
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Quote:
Originally Posted by AV8er48
Thanks Mark.

Van yes the stryker is epp foam.



P.S Mark were did you get your FunJet at? Got a web site?
I get all my planes from www.westwalesmodels.co.uk

Mark
www.rcflights.co.uk
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Old Jul 25, 2006, 05:33 AM
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erashby's Avatar
Utah
Joined Aug 2001
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Quote:
Originally Posted by RktMan
I'm not so sure about the statement that the 400-28 and the Mega 16/15/4 fly about the same...
I agree with you regarding the new breed of Lipo's. The battery is the only thing holding me back on propping up the FUN.
I had compared the Fun 400-23 to the Mega 4T, not the Fun 400-28. The Fun 400-28 is a higher KV motor than the Fun 400-23.

I also use no separate BEC with my Kontronic Smile ESCs. One I have on 4S lipos running 4 servos. It is burried in the middle of a foam fuselage with little ventilation (pulling 25amps) and it just gets warm.

Quote:
Originally Posted by Vantasstic
AV8er, I don't have either the Stryker or the FunJet (yet). The Stryker is made of EPP if I recall right and the FunJet is Elapor. The EPP is more flexible/damage resistant than the Elapor, but the Elapor loves normal CA adhesives.
The Stryker is actually ParkZone's Z-foam. Like Multiplex's Elapor it is a blended bead foam of EPP and ESP, I think. Comparing Elapor, Z-foam, and EPP. EPP is the least rigid and thus the most crash resistant. It is more resistant to tearing or breaking. Elapor is the most rigid or firm and needs less reinforcement with CF. After several nose-in crashes Taped EPP can just be retaped and look as good as new. Z-foam would show the wrinkles, but streaming can get them out a little. Elapor is more for landing not crashing-the crumples show and the foam brakes apart sometimes.

Just my $.02 worth of views on the foams that many refer to as EPP.
Eric
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Last edited by erashby; Jul 25, 2006 at 05:43 AM.
Old Jul 26, 2006, 01:35 AM
Registered User
Joined Jun 2001
107 Posts
Hi Jurgen and any expert here

I flew the FunJet on mega 4T on APC 6x4 (drawing about 29A) and on warp4 3T on APC 5.5x4.5 & 5x5 (both props drawing about 40A) on same FlightPower 2150-3S pack and strangely the FunJet flies faster on mega 4T on 6.5x4. I thought my warp4 is spoilt so I borrowed my friend's warp4 3T and also encounter same slower speed as compared to mega4T.

Do you know why is it so?

Thanks in advance.
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