Official Freewing 90mm F-4 Phantom II Thread

[Waconut]

Tried to fly my F-4 again today after adjusting the CG. It was a no go. The grass was too high and wet. Aborted the first takeoff run. I mowed the center of the runway and tried again. I still couldn’t get enough speed in the wet grass to rotate and waited a little too long to abort and hit a shallow drainage at the end of the runway which bounced the plane into the air and it came down on the front gear and broke the pin and the gear door.
Oh well I will order some parts and try again.

[locharrow]

"Tried to fly my F-4 again today after adjusting the CG. It was a no go. The grass was too high and wet. "

Been there! The F4 does not like wet grass..I've had enough aborts to know not to bother when it's wet. In the dry the beast just scurries along the grass building speed no bother. Now the gear door... After my tree excursion I was able to repair mine by cutting an oblong bit of a polythene type carton to fit on the inside and gluing it on with gorilla using a lot of pressure. Worked a treat. After repainting it was hardly noticeable .....Broken hinge replaced with a bit of judiciously bent push rod epoxied in place. All mince now though after last crash...but the good news is the new fuselage arrived yesterday so busy busy !! I was able to rescue my nose gear but it is now set in silicon as the mounting plates were bust and useless so had to be cut off. Naturally the weather is now for the next week so it will be a while before I get out.

[Tonybons]

E4 - the EZ balancer side uprights were very unsteady and showed me balanced at 190mm and having read a lot of recommendations on this thread that 190 was the correct CG and me knowing that I was tail heavy, I finally checked it on a balancing stand that I use for my turbines and it balanced at 210 mm which may not sound like a big difference but it was. Oddly enough RC Informer does a lot of his videos at my field in Apopka, FL and I had viewed his video on this phantom and he said on that video that he thought 190 was tail heavy. I think he was talking it should be at 170 but never confirmed that. I ran into him at my field and asked and he didn’t recall where he settled the CG at.

With my 2 admiral 5000 batteries and my set up, the “real” 190 mm required my batteries to be about as far forward as the hatch would allow. The 2 6000’s are about an inch or so further back - I’ll check when back home and will post the exact difference here. The 2 6000’s combined I believe weigh about 6 ounces more and are a little wider and a tighter fit but the extra flight time makes it enormously worth it.

take care.

Tony B

[e4dragongunner]

Tried to fly my F-4 again today after adjusting the CG. It was a no go. The grass was too high and wet. Aborted the first takeoff run. I mowed the center of the runway and tried again. I still couldn’t get enough speed in the wet grass to rotate and waited a little too long to abort and hit a shallow drainage at the end of the runway which bounced the plane into the air and it came down on the front gear and broke the pin and the gear door.
Oh well I will order some parts and try again.

I replaced my nose pin in phantoms 1 and 2 and will do so again with a pin from mcmastercar. You have some modeling to do ( grinding) but you can get it to work.

[Tonybons]

Tried to fly my F-4 again today after adjusting the CG. It was a no go. The grass was too high and wet. Aborted the first takeoff run. I mowed the center of the runway and tried again. I still couldn’t get enough speed in the wet grass to rotate and waited a little too long to abort and hit a shallow drainage at the end of the runway which bounced the plane into the air and it came down on the front gear and broke the pin and the gear door.
Oh well I will order some parts and try again.

Hi. What is your adjusted CG.

[e4dragongunner]

E4 - the EZ balancer side uprights were very unsteady and showed me balanced at 190mm and having read a lot of recommendations on this thread that 190 was the correct CG and me knowing that I was tail heavy, I finally checked it on a balancing stand that I use for my turbines and it balanced at 210 mm which may not sound like a big difference but it was. Oddly enough RC Informer does a lot of his videos at my field in Apopka, FL and I had viewed his video on this phantom and he said on that video that he thought 190 was tail heavy. I think he was talking it should be at 170 but never confirmed that. I ran into him at my field and asked and he didn’t recall where he settled the CG at.

With my 2 admiral 5000 batteries and my set up, the “real” 190 mm required my batteries to be about as far forward as the hatch would allow. The 2 6000’s are about an inch or so further back - I’ll check when back home and will post the exact difference here. The 2 6000’s combined I believe weigh about 6 ounces more and are a little wider and a tighter fit but the extra flight time makes it enormously worth it.

take care.

Tony B

Hey Thanks Tony....
Still trying to figure the 15mm difference on two different balancers....

Anyhoo I maidened phantom 1 at a level GC of 190mm and after that initial flight, I moved my battery's almost an inch back at least .... drastic positive difference in feel stability and easy high alpha approached and landings.
If you survived 210 seems a wide GC range is possible.... now mind you, I didn't say you liked it LOL .... but you got it back! :-)

[Waconut]

Hi. What is your adjusted CG.

I am sitting at 200mm, have not flown it there yet.

[e4dragongunner]

I am sitting at 200mm, have not flown it there yet.

Well just let me say I am damn curious ! Gods Speed !

[Waconut]

Well just let me say I am damn curious ! Gods Speed !

I flew at 208mm and had my hands full. It had very little lateral stability. Without the gyro for assist I probably would have lost it.

[e4dragongunner]

I'm thinking from my experience with this bird and all the reading ... 200 would seem the aft limit ... I am good with 195 for now... but who knows 200 maybe the MAGIC CG.. :-)

[Tonybons]

I am sitting at 200mm, have not flown it there yet.

Be careful at 200. Just my opinion, 190 might be safer.

tony

[Hugh Wiedman]

I replaced my nose pin in phantoms 1 and 2 and will do so again with a pin from mcmastercar. You have some modeling to do ( grinding) but you can get it to work.

Or you can replace the nose gear pin with the 1600mm Spitfire main landing gear axel. The head needs to be ground down slightly to a smaller diameter and then grinding flat spots in the correct position for the set screws but the length is the same (for a while when this got in vogue they were always sold out). I changed them on both my F-4's early on when I was "learning" to land these jets correctly and only bent one nose pin. Now that I finally figured out how to land, there's been no problem. The stock nose pin is much stiffer but will break rather than bend on a nose first landing (and of course cause quit a bit of damage to the gear doors and nose), while the Spitfire axel will not break, but instead bend, a preferable option which only needs to be fixed by replacing the pin. I "bench tested" the stock pin by hitting it with a hammer and it took a decent impact to snap it, while a slightly less impact bends the Spitfire axel but you can't break it. Posted pictures and results maybe a year ago, but can't find it now. Of course if you land correctly at a slow enough speed on the mains first, the stock pin is actually more durable. I've since put back the stock pins on both (and you just know I'll pull a nose gear first landing tomorrow now that I've stuck my foot in my big mouth).

[e4dragongunner]

Love it ... Spokes on a wheel , ala many path to the center! Great advice Hugh! Thanks for the re share!

[locharrow]

Genius required.... apply within. As my last post relates, my nose retract support plate was bust but the rest looked OK. I set it in silicon and it worked on the servo tester but not on in the plane. Tried the tester again and it was duff on that too. I searched out an old retract and fitted up the leg etc and again it worked on the tester. OK, I installed it in the plane, worked with the tester so I plugged it in to the board. So...............when the mains go down the nose goes up and vice versa. Change the mains -100 to +100 and +100 to -100. Mains changed but so did the nose !!

I'm going to try a separate channel for the nose leg controlled by the gear switch and muck about with the + & - values . Any advice on, or experience with, this fenonhen phenonome fennomam.....sort of thing would be more than welcome!!

Position filled........!! Set up on a spare channel...gear door timing was haywire but was able to set up delays on the nose gear to match the door OK. Brain buster..... so into the wine now !! Old man's privilege ...............

[Waconut]

Rookie question,
If I want to upgrade my F-4 to 8s what all do I need to change. Motor? ESC? Fan?
Maybe going to 8s will help with grass ops.
later!!
Anthony

[GliderGuy]

Rookie question,
If I want to upgrade my F-4 to 8s what all do I need to change. Motor? ESC? Fan?
Maybe going to 8s will help with grass ops.
later!!
Anthony

As a starting point, you may want to check out the manual and spare parts lists for the MRC 8S at:

https://www.motionrc.com/collections/rc-jets/products/freewing-8s-90mm-edf-f-4-phantom-ii-pnp

This should give you an idea of the different equipment list vs the 6s version.

-GG

[Evan D]

Agree... If you don't know where to start buying a 8S set up used but in good condition off RCG may be a great start too. While a Jet Fan/ HET/ Castle is a better set up it is more expensive and you need to know what to get. If you want to go that direction just ask.

[themudduck]

Posting a video - this is from the belly-tank position using the "InstaGO 360" stabilized camera and a custom 3D-printed mount. This camera shoots a 360-degree video and when its played the horizon stays level regardless of what the plane is doing, which makes for some interesting shots. There are two flights - first one at my club field with a Geotex runway and the second one at a much shorter grass field. My model also has a Freewing Eagle A3-L gyro which really helps smooth out the flight.

https://youtu.be/AH1bvB25zqI

[Hugh Wiedman]

Posting a video - this is from the belly-tank position using the "InstaGO 360" stabilized camera and a custom 3D-printed mount. This camera shoots a 360-degree video and when its played the horizon stays level regardless of what the plane is doing, which makes for some interesting shots. There are two flights - first one at my club field with a Geotex runway and the second one at a much shorter grass field. My model also has a Freewing Eagle A3-L gyro which really helps smooth out the flight.

https://youtu.be/AH1bvB25zqI

Absolutely love your videos with that InstaGO! Keep 'em coming. Would you do me a favor and take a picture of the camera attachment so I can get an idea of just how you mounted it? Thanks.

[Hugh Wiedman]

themudduck that looks like a custom made casing for the camera. How did you make it?