Shamu

Just a quick (and maybe a silly) question, do i have to set the CG with gear up or gear down on this model?

Tor Andersen

Hello i woud do the blance with the gear down becourse its that position you will land and go to low speed

Best regards Tor Andersen

rocketman-RCU

My Feedback: (73)

I forgot, What is the recommended CG for the F4D?

mikedenilin

My Feedback: (67)

C.G. = 8,75" or 22cm behind LE

Shamu

Hi all,

new Video from EDF Meeting in Nordhausen, Germany.

http://www.youtube.com/watch?v=inNyE..._order&list=UL

i have adjusted the Trim Flaps to neutral position and changed to a open duct system with inlet lip. The changes to the open duct resulted in 1kg more trust.

AUW: 8,5 kg
Trust: 6 kg
LiPo: 2x6s 6000mAh
EDF: XPS Dynamax Xtreme

Square Nozzle

My Feedback: (1)

Having seen Ray's SkyRay at the New England Jet Rally, I have to have one. I want it as a club field flier. The field has a 400 foot grass runway with power lines a moderate distance from one end (Takeoff to the south). My engine choice leans towards a 19 to 22# thrust engine so I can get up and out in a hurry. My concern is, will a Jet Central Rabbit at 3.6" in diameter fit in without compromising clearance for plumbing and wiring? I saw previous posts about installation of a P-70. That's 3.7" diameter so I have to assume the Rabbit or even the Wren 100 (3.5" dia) are good choices.

Square Nozzle

My Feedback: (1)

Hello to all you GJC F4D owners/flyers. I'm a year late getting into this F4D thing. I have the engine (P100). The plane is painted and likely in QC prior to shipping in about a week. In prior posts there was a lot of discussion about using a gyro on the ailerons to control wing rock. Using all of your experience I will likely do the same. Probably use the JR 270 as Mike suggested to Frank last year. Was it ever determined how to hook up the gyro with dual elevon servos? The Futaba gyro with two ins and two outs sounds straight forward but will it work in a JR system? Connector mods required obviously. Also considering raising the wing tanks to avoid ground interference. Ray sent me an Email stating that he flew his F4D with the tanks installed (raised 7/8") and the plane got very pitch sensitive. Removed the tanks and all was well. Maybe 7/8" puts the tanks to close to the wing and creates funny air flow? My first flight will likely be without tanks just to be on the safe side.

I hope you all can guide me down the path to a successful maiden.

funflyerf4

My Feedback: (6)

Hi John I still only have the one flight on mine.I sold the P-70 and also going to put one of the 100's in it. I still want to put a gyro in it.

Square Nozzle

My Feedback: (1)

I have the P70 in my R-54. Lots of get up and go in that plane but very slow on throttle response. I ran the P-100 last Saturday along with Jeff Lynds P-120. The throttle response is light years ahead of the P-70. And you'll love the simplicity of plumbing and electronics installation. So simple even a caveman can do it! The P-100 is only .1" larger in diameter than the P-70. Having had the P-70 in your F4D, do you anticipate any difficulty putting the P-100 in?

thunderceptor

Here are the latest videos of a Skyray:

[youtube]http://www.youtube.com/watch?v=tyfggYSbB2k&list=UUVIzlH6kWykD8EfzfnXyekg&index=1&feature=plcp[/youtube]
[youtube]http://www.youtube.com/watch?v=Xq8PE2GAaz4&feature=related[/youtube]

The model has highly modified landing gear to improve stability and strenghtness.

Square Nozzle

My Feedback: (1)

It's time to wake the sleeping F4D community. I just received my F4D from GJC and I'm reasonably pleased with the plane. Being a very picky person about fit and finish I guess I'll have to say well done GJC. It's the NATC, yellow wings, blue fuselage version. Power will be by JetCat. A P100 which to my surprise, fits without modification to the mount system. It appears that they have changed the tank configuration in that they fit into the sides of the fuselage with no difficulty and there is no tank to tank interference at the bottom center line. It closely resembles what SAP2000 did to his tanks. My only concern is the length of the tail pipe. Consider that I have set the engine nozzle to tailpipe bellmouth at the JetCat recommended gap of 3/4". To keep the tail pipe rear end as far forward as possible I have placed the engine as far forward as I can get it and still have 5/8" of tailpipe sticking past the rear plane of the fuselage. Understand that I can make a new mount that will move everything forward so the tail pipe doesn't stick out but then getting CG at the correct location becomes an issue. I'll have to place batteries, UAT. pump etc. in the rear of the plane. So comes the question and request for recommendations. How have you F4D owners handled this situation? My thought is to get a new pipe that is 2 1/2" shorter than the supplied pipe. I'll be calling GJC later today to hear what they recommend.

Square Nozzle

My Feedback: (1)

[quote]ORIGINAL: Square Nozzle

mikedenilin

My Feedback: (67)

Hi John,

Thank you for waking up this thread. We have shorter pipes that might work on your P100. The longer pipe was originally designed for smaller engine, like P60-70, so they have proper spacing for cooling and thrust. For P100 we can offer shorter pipe and larger diameter that will accommodate the proper spacing. Send your inquiry to [email protected] and Cindy will take care of it.

Regards,

Mike

Square Nozzle

My Feedback: (1)

Thanks Mike. I spoke to Dave Murray today and he offered a shorter pipe through Tam Jets. I will need a 11 1/4" pipe to allow the engine to mount in the rear most position to minimize issues with equipment placement to establish the correct CG , maintain the engine to bellmouth clearance of 5/8 to 3/4" and get the aft end of the pipe inside the rear plane of the fuselage. I contacted Tam and he will be building the P100 size pipe at 11 1/4" length. Thanks again - I'm very satisfied. Great customer service.

funflyerf4

My Feedback: (6)

I picked up a Gya 401 gyro for my F4d and have a Rabbit 100 now for it. I have never used a gyro before any hints on installing and adjustment settings?




Frank

Square Nozzle

My Feedback: (1)

Frank and All, I will be installing a JR 370A gyro on the rudder. I stole an idea from Ray Davis and have the rudder servo and linkage completely enclosed in the tail area. No external linkage to dirty up the exterior of the vert fin. Now the real tough problem. Someone tell me why I shouldn't permanently glue the vert fin to the fuselage. I see no reason to ever have to remove the fin/rudder assembly. The clamp and screw designed to hold the fin in place is absolutely impossible to get at to tighten it. I do not want to drill an access hole in the fin base. Access to the rudder linkage is very easy with removal of the tailpipe. So why not glue the fin in place and be done with it??

funflyerf4

My Feedback: (6)

Hi John can you tell me the diameter of both ends of yor new pipe?

Frank

Square Nozzle

My Feedback: (1)

Frank, this is a double walled Tam pipe sized for the Jetcat P100.

Bellmouth ID 3.17"
Bellmouth OD 3.97"
Tailpipe ID 2.750"
Tailpipe OD 3.2"
Length 11 1/4"

The bellmouth mounts at the rear hatch rear bulkhead plane and the aft of the pipe ends up about 1/2" inside the rear of the fuselage.

RC_MAN

My Feedback: (11)

I have a JETS MUNT VT80 Turbine. Is there a thrust tube for this set up?

Square Nozzle

My Feedback: (1)

When I got my pipe from TAM I first set the engine where it would be best positioned for CG. Then I calculated the pipe length knowing the recommended tail pipe to exhaust nozzle spacing and where I wanted the pipe exit end with respect to the rear of the fuselage. I didn't want my pipe to stick out past the rear of the fuselage. My final pipe length was 11 1/4". Called TAM with the engine type and pipe length and had one made. He sized the diameter based on the engine type. Mike from GJC said he has shorter pipes available that might work, but I believe diameter is also important so you don't kill power.

siddus74

I know this is an old thread but can some one advise me on of the elevator and aileron throws for the F-4D SKYRAY 1/9 ARF PRO, just picked up a 2nd hand one ...

Scott.

CJ2002

Drop a PM to Andy Bascombe (comes here as basea)...he'll be able to help.

Rgds,

Dick

basea

Hi Scott

You've probably got my old model. Go for max movement you can get on the elevens. You need more elevator movement than aileron as deltas are less responsive in pitch compared to conventional planes. You will need a gyro on roll/yaw unless you always fly in calm conditions. Again this is a delta trait. Hope this helps.

siddus74

I may very be your old model .... did yours have a DS8411 on the nose wheel?

What can I expect from the model as far as take off and landings go? Its not overly light so I expect to be bringing it in at more than walking pace but deltas normally are quite well behaved with the high alpha etc ...

Any advice you can give me would be greatly received, I dont have a gyro so Ill just have to suck it and see ... It has a P60 in to btw.

Did you fly it much?

Scott.

basea

Sold mine without servos. Take off no problem with a P60 - will leap airborne. On landing slow it down to get the nose up. As you say deltas well behaved at high alpha.