Official Freewing 90mm F-4 Phantom II Thread

[rlcamden]

Has anyone installed the 3672-1900kV inrunner in this bird? If so, what are your thoughts?

[Hugh Wiedman]

Wow. Didn’t expect that. Thanks so very much for taking the time to detail so much good information. I’ve taken a screen shot and will have your info next to me as the assembly progresses.
Thank you again.

One more thought, you may want to change the front gear nose pin to one that is not as brittle and subject to snapping. On both my F-4's, I initially replaced that nose gear pin with the main gear axel pins from the 1600mm Spitfire. Same length and diameter, however you will need to grind a longer flat spot on the axel where the grub screw contacts the axel. Additionally, the head end will have to be ground down a bit so it rotates freely. This pin will bend instead of breaking like the stock F4 nose pin, and in a rough landing will end up bent, but cause no further damage that a broken pin will definitely cause. The stock pin is slightly harder, and will take a slightly harder landing before breaking that might cause the "modified" pin to bend.

I used these on about 30-40 of my first flights until I got somewhat proficient in landing properly. Bent a couple nose pins, but no other damage. After that, I put back the stock "stiffer" pins and haven't looked back. Just a thought.

[GliderGuy]

Update: I flew my 6S stock F-4 with the MKS HV69 high torque servo driving the full flying stabs yesterday and today. This servo gives me an added level of comfort. Although the stock FW servo did last many, many, many flights before becoming intermittent...repairable crash resulted.

The HV69 is smaller in physical dimensions than the stock Freewing servo, So, I hand crafted an adapter to securely mount the HV69. Plywood, CF or whatever you have handy will work fine. The servo drive is 25 tooth, just like the stock FW servo....no issues using the same horn. You may need to take the vertical stabilizer off to make the removal of the FW servo and installation of the HV69 go more easily.

i see that motion sells the HV69. I am also using these in my MiG-29.

https://www.motionrc.com/collections...pters-mks-hv69

If you have an application that needs a reverse servo, there is no reverse HV69. I am using a Futaba SR-10 servo reverser on my MiG-29 HV69 servo set-up. It has proven to be VERY temperature stable. The only other option is to re-wire the guts of the HV69 to reverse it. Kinda tricky in small spaces.


-GG

[50 Fly]

Hobby Squawk noob here... F-4 unusual question probably... Installed Xicoy X-45 in stock F-4, it flies very well with stabilization. Have 12-15 flights, no problems, no damage. The issue is, while I find it rolls nicely horizontally (with correct slow-roll rudder inputs), when I go vertical, the rolls are corkscrews. Have tried differential, mixed proverse aileron-rudder, to no avail. Still wonky, not axial. My CG is further aft than recommended, about 10mm. Since I have 10lbs of thrust in a sub-7 pound airplane, vertical rolls are no problem. Anyone have any intel on this? Is it the force setup - anhedral stab and upswept tips? Might be I need a new wing, mine is warped and thus carries about 3/16" aileron offset (gotta say, that first takeoff was fun, almost rolled in.) I'll probably call Motion for a new wing. Thanks for any tips!

[locharrow]

Hobby Squawk noob here... F-4 unusual question probably... Installed Xicoy X-45 in stock F-4, it flies very well with stabilization. Have 12-15 flights, no problems, no damage. The issue is, while I find it rolls nicely horizontally (with correct slow-roll rudder inputs), when I go vertical, the rolls are corkscrews. Have tried differential, mixed proverse aileron-rudder, to no avail. Still wonky, not axial. My CG is further aft than recommended, about 10mm. Since I have 10lbs of thrust in a sub-7 pound airplane, vertical rolls are no problem. Anyone have any intel on this? Is it the force setup - anhedral stab and upswept tips? Might be I need a new wing, mine is warped and thus carries about 3/16" aileron offset (gotta say, that first takeoff was fun, almost rolled in.) I'll probably call Motion for a new wing. Thanks for any tips!

This is a "must see" F4 ........Video please !!

[50 Fly]

This is a "must see" F4 ........Video please !!

Yep, wish I could oblige. Have videos, can't seem to get them to load. It's a bad boy!

[GliderGuy]

Edit: Oops...I missed the fact that this is a gas turbine. RF Chokes are N/A. Sorry for the confusion.

50 Fly....page up and read post 4799 on April 6.

All my F-4s have required the aileron offset. A new wing may be this same way. Confirmed by MRC cust serv...he said he also has aileron offset. Others in this thread have also made the same observation.

I am using stock CG and I get clean rolls. You may want to experiment.

Also suggest you spend some time reading the prior posts....lots of good info on the F-4.

-GG

[Flamingo]

for my second Phantom I have chosen the recommended FW 12blade inrunner w/1835KV driven by thick 4068 inrunner
will add some weight on all components but hopefully resulting power will satisfy

driven by 150A w/ext. BEC and Futaba current sensor

[locharrow]

That's same fan as I have in my F4. I run it on a 150Yep esc on low timing...........bags of power ........especially when using the 5400 Turnigy Bolt 4.35 cell lipo. 6000 HRB 50C is also a great battery for this unit.

[Hugh Wiedman]

Flamingo and locharrow, same fan I'm now using in both my F-4's, as well as the F-16 and F-18. THE ONLY 90 mm fan for me as I've finally upgraded all my 90mm's to the 12 blade inrunner. The F-4, IMO, is a beast with that fan, 4 minutes of exhilarating flying on an HRB 6000 and the sound is sooooooo sweet. It was completely transformed from using the original 9 blade, "whining like a school girl", 1750 Kv outrunner, so in my case it was a huge upgrade. Without any experience with the 9 blade inrunner, can't say what the difference is, but now it gets off our grass runway like it's being chased by a cheetah!

[locharrow]

Hugh ..if you love the sound of the F4 12 blade then invest in an FMS Red Arrows 80mm Hawk...it is the sweetest sounding edf of the lot (imho)..Great flier, fast or slow. It's my go to plane for a quick flight. Nothing it can't do. It will outside loop or knife edge all day long if you want it to.

[Hugh Wiedman]

Hugh ..if you love the sound of the F4 12 blade then invest in an FMS Red Arrows 80mm Hawk...it is the sweetest sounding edf of the lot (imho)..Great flier, fast or slow. It's my go to plane for a quick flight. Nothing it can't do. It will outside loop or knife edge all day long if you want it to.

Interesting, thanks for the tip. I sort of use my Avanti and Stinger 90 for goofing around and practicing aerobatics, but one can't have too much fun aircraft to fly, and it's a real looker too!

[davegee]

Hi Guys: I have an old Freewing F-4 that I used to fly a lot of a 6S battery supply. It had some gremlins come up electronically, so I decided to retire it and am giving the foam body to a Civil Air Patrol unit locally to hang up in their hangar.

I have been testing my receiver and the motor, and they seem to be in good working order. I don't recall any really bad crashes with it back in the day.

I have a couple of questions:
1) The UBEC has a red and black wire on one end coming out of the battery leads, and a plug on the other end. I'm assuming it just plugs into any open port on the receiver. Is that correct?
2) And could someone explain what an UBEC does, I've either forgotten or never really understood it.

I'm thinking I might buy the ARF+ grey version of this plane to put the motor, ESC, UBEC from the old plane into the new plane.

Thanks for any help on this!

Davegee

[GliderGuy]

Hi Davegee - Sounds like a fun project. You don’t say how old your system is nor the brand.

Keep in mind that the radio technology keeps improving all the time. In my opinion, avoid the temptation to save a few dollars and then risk crashing your new bird due to an older technology RX.

Don’t take this as a bash on older radio gear...there are those who swear by their older systems. But, if you have the chance, why not take advantage of the advances? But....new RXs may not be compatible with your TX.

And now pardon me while I get on my soapbox (the other readers are rolling their eyes about now...LOL), but PLEASE take the time to search “ferrite” or “choke” or “RF choke” and read/learn/buy/install these. The high current ESC of the F-4 (and others) deserves some special consideration in this regard. Just saying....I lost an F-4 and an A-10 (twice) BEFORE I began to use RF chokes, and I haven’t lost a bird (due to a radio glitch) since I started using them.

UBEC = Universal Battery Eliminator Circuit. It takes the “too much” voltage of a LiPo battery that you use to power the EDF motors and reduces the voltage to a level that the receiver can tolerate. Mine plugs into the terminal on the receiver marked “B”.

Regarding the ESC and motors and UBEC....they may be OK, but let’s see what the experts have to say.

How has all this equipment been stored? Outside in a humid garage? Indoors in a controlled environment? The reason I ask is that humidity can penetrate plastic ICs and initiate internal circuit corrosion effects over time....accelerating the failure mechanisms. Capacitors also degrade over time, especially if they are electrolytic and just sitting around w/o any voltage applied.

Finally, page up and read post 4799 on April 6.

Keep us posted on your progress.

-GG

[Hugh Wiedman]

Finally got around to installing the last of my upgraded 12 blade inrunners. Now all my 90mm's have this beast. Already got a bunch of flights on my 1st 4-F and really love it, especially compared to the original 9 blade 1750 Kv outrunner. The final bird was my F-4 Blue Angel and the fan I pulled out had the blades that didn't exactly look like new. This happened on it's last flight as I had to set it down in a agricultural field (that's a long story I'm not going to bore anyone with) and it must have sucked up enough dirt and rocks to choke a horse. Good thing I waited to install the new fan instead of taking it out again, doubt it would have gotten off the grass, and if it did, who knows how it would have (or have not) flown.

Anyone need a slightly used 90mm 9 blade 1750 Kv outrunner? I'll even include free shipping! Nothing a new fan blade couldn't fix.

[locharrow]

My wife would love fan that set up in the kitchen ! She could throw vegetables at it and have the makings of great soup!

[Flamingo]

could replace rotor w/12blade from motionrc for just 6$
just one centre screw
and mark position of cone to shaft adapter, my was balanced

the cleaning of the stator can be done in the kitchen, of course😏
after your great soup😋

[locharrow]

Teknikal stuff....today sucked up a fir cone on take off with my SU 35 and burst one of my two 12 blade edf nose cones and a fan blade. I have pair of 10 blades but no nose cones for them. Is there a significant power loss running without the nose cones, never tried it ....be weeks before new 12 blades and cones arrive ......info appreciated

[GliderGuy]

Teknikal stuff....today sucked up a fir cone on take off with my SU 35 and burst one of my two 12 blade edf nose cones and a fan blade. I have pair of 10 blades but no nose cones for them. Is there a significant power loss running without the nose cones, never tried it ....be weeks before new 12 blades and cones arrive ......info appreciated

Put them on and go fly! You’ll likely not notice any cone to no-cone difference with a given fan at these scales and speeds. No need to pass up flying weather...just for not having cones.

-GG

[locharrow]

Put them on and go fly! You’ll likely not notice any cone to no-cone difference with a given fan at these scales and speeds. No need to pass up flying weather...just for not having cones.

-GG

Put on the 10 blade and it wobbled like Bent adapter shaft.....motor shaft run great on fingernail so looks like cheap fix!