Official Freewing 90mm F-4 Phantom II Thread

[thisguy65]

Has anyone experience this with their 8S F-4?


Coming off throttle, wants to nose down
Applying throttle wants to nose up.

Regardless of what I do can not get the f4 to stay in level flight.

"I cannot trim it just to fly level. It either wants to nose dive off power or climb with power
And it’s not gradual it’s like someone is pushing the stick forward and backward"

[Evan D]

Read on the RCG thread, there was a report there. Mine doesn't do that but I don't have a factory 8S, I have a JF. If it was a slight amount I'd say it's balance and trim but not a sudden pitch which I would say it thrust line.

[thisguy65]

Read on the RCG thread, there was a report there. Mine doesn't do that but I don't have a factory 8S, I have a JF. If it was a slight amount I'd say it's balance and trim but not a sudden pitch which I would say it thrust line.

Thanks, It's actually a friend of mine in FL. I remember reading about this in passing but could not find it on the RCG.

[Evan D]

I remember Bob-A-Roo being very vocal about it.

Thanks, It's actually a friend of mine in FL. I remember reading about this in passing but could not find it on the RCG.

[Spitfire4life]

Thanks for the video Stuart, the tip you gave on detailing the "battle damage" was quite cool! Nice job, I like that idea.
Some of us have found that the original linkage for the elevator connector is fairly weak and the plastic keeper can come right off under flight stress, have you strengthened yours?

Hey, no actually, never found that myself, but small discrepancy’s can creep in when these are assembled by hand I guess so always best to check, so this is a good pointer for all.

S

[Evan D]

Many have, or have had to, redo the whole elevator/ servo linkage, mount and bearing plate. Most have added wood or plastic mounting around the servo so it's more firmly anchored. Most have changed the servo to stab linkage. This is a multiple issue fix. The first is making something better than a "L" and keeper as some have had this forced off in flight or crash. The second is the rod itself is great for the force a 9g servo can handle but just not right for this application. Some have swapped out larger diameter rods and others have added a carbon tube over the stock rod. The third is the ball and link on the servo, again good for a 9g setup but not for this. I upgraded the rod and "L" end on mine but left the servo end ball link and after a few flights I noticed my trim had changed, the plastic link was bending.

I feel the linkage there is just not sufficiently designed for the forces it's exposed to. Not what I would call a small discrepancy.

[Ben De Vizio]

Hi All,

Three things, One on the 8S Phantom does anyone know the specs of the Elevator servo i.e speed and torque but also what the voltage is on the bec in the system

Also on the topic of Grass 6S performance,my Phantom performs valiantly on a 40x40 grass strip here in the UK. I've attached some videos to show this:

https://www.youtube.com/watch?v=aJnjSXNdl9U and https://www.youtube.com/watch?v=KFlAWjE4BVU

Apologies for the quality but was record on an Iphone X

Thanks in advance for the Specs

[spook]

Should be the 30g servo with 750mm lead

https://www.motionrc.eu/products/freewing-30g-digital-metal-gear-servo-with-750mm-29-5-lead

I changed mine to a very high quality metal hv servo with more than double torque, more precision and same speed

[Ben De Vizio]

What servo did you change to out of interest Spook?

[spook]

I think according to the specs the Savox SV 1260 MG or the D Power 4180SG ís a good choice. Took the D Power for mine but I think there are similar on the market.
I use also an external BEC because I got a kit version with my own electronics anyway.

Had a mishap with a prop plane and a elevator of this type and dont make any compromise. The loads can be huge.

[Bogietrim]

After about a 1.5 year hiatus from RC due to life I finally am getting the chance to tinker again. I have been waiting for the F4 and the F18C for years. I just purchased the Phantom 8S PNP last week and assembled it in an evening. They just keep getting better and better with these jets. I ended up changing out the flap control rods as well as changing the mounting position to get the flap extension I wanted. The only other slight modification was cutting some foam from the cockpit to accommodate my batteries. I started with my CG a bit forward of the book. Throws were set with 3 rates using 3 flight modes. Elevator at the recommended position with up elevator added in the mix. Nose gear steering on separate channel. Maidened it today. I was surprised at how short the take off roll was. It practically leapt into the air and climbed out with authority. It was very pitchy and I thought it as tail heavy even though I checked the CG again prior to take off. Flaps up and went to mid rates. That tamed it a bit, so I went to low rates and that was a little better. I then knew I had way to much elevator travel. So, I flew around the pattern trying to trim a bit waiting for my timer. I was flying at 1/2 throttle most of the time. This thing is a missile! I kept waiting for the timer.....I look down and there is still 45 secs left so I set up for landing. I touch down and taxi back. I go to check the batteries and they were both at 20%. I was using a set of Zippy compacts 5000mah. I then go to change out batteries to the Admiral 6000 packs. Then went to reset the timer on my radio and realized that it was set at 5 minutes!! I had cruised around for about 4.5 mins on a set of 5000's! Yikes! Just glad I wasn't really heavy on the throttle or this could have ended differently! Changed packs to the 6000's, set the timer to 4 minutes, changed a few settings to reduce throws and flew again. Flew a bit harder this time and came down right at 4 mins and exactly 20% left. Still need another flight or two to get used to this bird, but so far it flies pretty solidly despite my rusty thumbs. Definitely one bird that required throttle management on final. I have the camo version and like the contrast from the light colored belly. It really helped me with orientation. That's all I have for now. Time for graphics and other add ons.

[Bogietrim]

Should be the 30g servo with 750mm lead

https://www.motionrc.eu/products/freewing-30g-digital-metal-gear-servo-with-750mm-29-5-lead

I changed mine to a very high quality metal hv servo with more than double torque, more precision and same speed

I think I will be doing this as well. Seems to be a little weak and am looking for better fidelity.

[BreakX101]

Has anyone experience this with their 8S F-4?


Coming off throttle, wants to nose down
Applying throttle wants to nose up.

Regardless of what I do can not get the f4 to stay in level flight.

"I cannot trim it just to fly level. It either wants to nose dive off power or climb with power
And it’s not gradual it’s like someone is pushing the stick forward and backward"

im having the same issue and cannot get it to stay level. You cant even move the battery back enough without the straps coming off...

[Evan D]

Really? Give us a break. You can't move the strap? Heck a few screws and you can move the whole battery tray.

im having the same issue and cannot get it to stay level. You cant even move the battery back enough without the straps coming off...

[BreakX101]

Really? Give us a break. You can't move the strap? Heck a few screws and you can move the whole battery tray.

Thats not the point. If you sell a plane PNP and its 8s then the setup should accommodate it without any modification. This whole its part of the hobby bs is getting old.

[Evan D]

I'll bite, and they are supposed to predict every battery? It's a battery strap. You can't adapt to a different battery position?

BTW what battery are you using? Any mods to your plane?

[The RC Geek]

Hey guys, I swapped out the stock 6s 90mm fan with an 8s JetFan 90 setup in my refinished F-4. I really liked how the airplane flew on 6s, but my primary complaint was the flight time. So, that was the primary motivation in going to 8s and I was able to get an additional minute of air time for slightly less capacity. Also, the airplane picked up a little more speed and vertical from it as well. Interestingly, I like how the airplane lands a little more now with the slightly higher weight too as at times, on 6s, the airplane got floaty in even just slight winds. I've really been loving flying this airplane!


Chris

[Hugh Wiedman]

Hey guys, I swapped out the stock 6s 90mm fan with an 8s JetFan 90 setup in my refinished F-4. I really liked how the airplane flew on 6s, but my primary complaint was the flight time. So, that was the primary motivation in going to 8s and I was able to get an additional minute of air time for slightly less capacity. Also, the airplane picked up a little more speed and vertical from it as well. Interestingly, I like how the airplane lands a little more now with the slightly higher weight too as at times, on 6s, the airplane got floaty in even just slight winds. I've really been loving flying this airplane!


Chris

Wow, gorgeous livery, outstanding flight and a great video. Doesn't get any better than that!

[A.B. Jones]

Evan D, thank you so much for your information. I don't know what type of battery is there, it looks like 6 triple A's put in a plastic over. I haven't tried
moving the battery further to the rear, I'm not to sure the wiring is long enough. If you hear a loud scream and an explosion for New Mexico, I fixed it!
Thank you! A.B.

[Evan D]

Welcome A.B.! Mine did four air shows this weekend. Spectators were standing and cheering... :)