Official Freewing 90mm F-4 Phantom II Thread

[paulsnapp]

I was watching RC Informers F4 videos where he cautions that the book CG of 190 is wrong and that it should be balanced between 175 and 180. I am curious what you guys have found to be the best CG?

[paulsnapp]

Has anyone used one of the Eagle A3 gyros from Motion RC in this F4 Phantom? If so, what did you find the max gain percents to be? Thanks!

[Ks.jetflyer]

As soon as we get some decent weather, will give it a go. Was concerned I might let the smoke out.

[rifleman_btx]

I concur on the boat prop theory. As my 9 blade didn't really have the initial push the 12 had, but definitely had more top end speed.

[Hugh Wiedman]

I put the 9 blade 1900kv inrunner in my F-4. Wasn't impressed with performance or sound so decided to experiment a little. I took the 9 blade off and put a 12 blade on. Charged up a 5000mah 65c batt, hooked up my watt meter. Initial amp draw was131.5, after about 5 second it was 126 amp. Didn't pay any attention to watts or volts, was mainly concerned about amp draw. Static thrust felt a lot better than the 9 blade, sound was awesome. Any thoughts or input about this setup would be appreciated.

Interesting, wasn't sure you could do that, but don't know why not. I will say that the 12 blade 1835 Kv inrunner on a fully charged 6200 SMC draws 129 Ah and 3210 Watts initially. As the battery is drained down, the Ah draw will also be reduced, so you're in the same ballpark anyway. I've put the 12 blade in 6 of my jets so I don't really have a good assessment of the 9 blade 1900Kv fan but would love to hear from someone who has experience with both as well. Clearly the motor diameter (and weight and maybe windings) are different by a good 3-4 mm so what's the advantages of one vs the other (other than the obvious difference in cost). I will say all my jets with the 12 blade fan get off the grass in what I feel is a relatively short distance and they seem to handle vertical and any extra weight better than the 1900 kv 9 blade that I stuck in my Stinger 90 (which originally came with a crappy 1750 kv outrunner). Assume it is somewhat similar to a boat prop, where more blades give better start up thrust and power throughout but maybe not as much top end speed?

[Ks.jetflyer]

I put the 9 blade 1900kv inrunner in my F-4. Wasn't impressed with performance or sound so decided to experiment a little. I took the 9 blade off and put a 12 blade on. Charged up a 5000mah 65c batt, hooked up my watt meter. Initial amp draw was131.5, after about 5 second it was 126 amp. Didn't pay any attention to watts or volts, was mainly concerned about amp draw. Static thrust felt a lot better than the 9 blade, sound was awesome. Any thoughts or input about this setup would be appreciated.

[Hugh Wiedman]

Got out yesterday for a few flights with the F-4. I've been flying it on a 814 gr SMC 6200 with flight time just under 4 minutes but finally grew some cajones and put the 903 gr SMC 8100's in to see how it performs. With the 12 blade inrunner fan in it, I'm not really sure that I noticed much, if any, loss of performance. Maybe an extra 10 feet of take-off run to get off the grass and certainly no degradation of vertical or maneuverability. But definitely noticed aa nice increase in flight time to 5:20. Whoopi!! :hugging: From now on, that's my set-up and both F-4's are going to be fighting with my F-16 for priority on those batteries. Only have 4 of them so may have to bite the bullet and get a couple more!




So this looks like a low strafing run over some rice paddies during the war! :lying_face: Maybe not, especially with the electric lines in back. :face_with_symbols_o

[Coconut]

Beginning of you guys descriptions, sound like I'm getting ready to read an erotic book .

[locharrow]

"Not sure what I am looking at. I assume the view is up the tailcone viewed from the rear of the plane? Did you cut off the plastic tail cone in order to see this? If so, is it visible without cutting?"

Looking up the tail cone I saw and felt a huge lip at the join of the cone to the fuselage. I cut the cone off flush and that left that white crescent shaped part still glued to the fuselage. I took that part out and glued it in the correct position as in the left hand photo then glued on the cone. You can see by the gap between the black dots on the right hand photo how misaligned it was.

[paulsnapp]

QUOTE=rcaviator;n333579]I just maidened my F-4 and found the same issue with the ailerons as was posted above. Mine are off 5mm. This the most I've seen. Anyone know of what it takes to correct this??

Don't put all the blame on malformed wings.....this is what I found when I had a close look at the tail cones.




[

The cone was glued on way off it's correct position, how anyone could do that beats me when the "lock" position is in the mould! I shudder to think what this would do to the thrust line, corrective aileron would be essential but not because of the wing!!

Wee bit of a tidy up for the wing wires at the fan, 1/8th cross grain balsa pressure fit into the recess...



[/QUOTE]

Not sure what I am looking at. I assume the view is up the tailcone viewed from the rear of the plane? Did you cut off the plastic tail cone in order to see this? If so, is it visible without cutting?

[Elbee]

I just maidened my F-4 and found the same issue with the ailerons as was posted above. Mine are off 5mm. This the most I've seen. Anyone know of what it takes to correct this??

RCA, I agree with both GliderGuy and Evan D, after checking wing tips for 'all square', the elevators would be my second 'go to'. I have not had this issue, but I did mod both of the wingtips with the addition of an aft facing LED housing and light. In the process I taped each outer panel flat to the bench while supporting the inboard section to glue the mounts flush. Might of done something to help presuming there is an OEM warp present. Best, LB

[locharrow]

QUOTE=rcaviator;n333579]I just maidened my F-4 and found the same issue with the ailerons as was posted above. Mine are off 5mm. This the most I've seen. Anyone know of what it takes to correct this??[/QUOTE]

Don't put all the blame on malformed wings.....this is what I found when I had a close look at the tail cones.




[

The cone was glued on way off it's correct position, how anyone could do that beats me when the "lock" position is in the mould! I shudder to think what this would do to the thrust line, corrective aileron would be essential but not because of the wing!!

Wee bit of a tidy up for the wing wires at the fan, 1/8th cross grain balsa pressure fit into the recess...

[Evan D]

Some have found their stabs not even... Also answered in the other thread.

I would also sight down the vertical stab to see how it looks too (not just the rudder center).

[GliderGuy]

I just maidened my F-4 and found the same issue with the ailerons as was posted above. Mine are off 5mm. This the most I've seen. Anyone know of what it takes to correct this??

#1 Given it seems to be a somewhat repeated manufacturing issue, you might determine which wing is the offending wing and address it to MRC customer service for a replacement. Set some “true” and stiff wood pieces/dowel rods or carbon rods against the bottom of each wing about 1/2 way out and have these extend a foot or two forward. Measure the distance to the ground or workbench at the forward tips of these. You will find the offending wing or not. There may not be a problem! Make certain she is sitting level on the mains (maybe a bubble level sitting span wise against the flat of the bottom side of the fuselage).
#2 Or…You could add some right rudder trim and back off the amount of aileron trim and re-set the nose gear alignment so it taxis straight and live with it.
#3 Or…You can leave it as is and just fly it. That’s what I do. It doesn’t seem to impact the flight. However, if you acrobat a lot and demand precision, it will mess with your flying.
#4 Or…Carefully align your FFS/elevators. You can use the same stick or rod technique above. If they ARE aligned, you could always misalign them slightly so less aileron trim is needed.

IMPORTANT***Make sure the flaps are aligned identically on both sides when fully up. Since yours seems to be worse than most, I am betting your full flying stabs/elevators are not aligned with each other.

Let us know what you find.

-GG

[rcaviator]

I just maidened my F-4 and found the same issue with the ailerons as was posted above. Mine are off 5mm. This the most I've seen. Anyone know of what it takes to correct this??

[Elbee]

[QUOTE=Habukeeper;n333445]Hi guys. Great info here. Thanks for that.QUOTE]

HK, Welcome to Hobby Squawk. Looking forward to inputs, as well. Best, LB

[Hugh Wiedman]

Hi guys. Great info here. Thanks for that. I have a freewing F-4 coming and I have a Spektrum NX8 radio to use. I also already have a 6s 7000mah 22.2 v 30c battery that I got for my draco. So the question is will the stock ESC for the 6s freewing phantom handle a 7000mah battery and what Spektrum receiver would you guys recommend? Thanks in advanced for Any suggestions.

GliderGuy gives sound advice! I would suggest your first EDF might be something like the Avanti or Vulcan. You'll have to get used to the difference in speed with an EDF versus the Draco and the Avanti is a much more forgiving aircraft that also flies well at slower speeds, but you'll find you can get into a bad orientation much quicker with an an EDF compared to a prop plane. The biggest difference is in landing as you'll have to "find" the perfect speed (too fast and it's back to the repair shop and too slow and it stalls-back to the repair shop) and orientation (nose high touch down) to land in. With that said, the Stinger 90 was my first EDF (and it was a hand full for me at first because I thought I had to fly it at 80% throttle or more and just couldn't visually or mentally keep ahead of it at first) and the F-4 was my second EDF. Landings are generally the #1 areas of mishaps but I see most guys going to their first EDF usually overcontrol the aircraft and they quickly get into a bad orientation, meaning they put too much control surface input in before they are ready to handle it. Low rates are usually a good place to start if you're new to EDF's.

Regarding the battery, yes, I really believe in the SMC's. I fly most of my EDF's on the 6S 6200 40C (weight 814 gr an true 40C) but also occasionally use their 8100 20C (which is actually a true 24C) in the F-16 (same fan & ESC) and even in the F-4 as it weighs only 900 gr but gives an extra minute and a half of flight time.

Regarding the RX, that's kinda like asking "What's your favorite Food"? Mostly personal preference and there is no wrong answer. I personally use Spektrum AS3X RX's exclusively (that's just what I started with and know). So I would recommend the AR637T mounted behind the battery bay with a 12" extension going to a 4651T remote receiver for your best signal (along with some of GG's RF chokes). Assign the FM's to either the gear or flap channel and you can program 2-3 different gain profiles. With mine, I'm around 45/50/55 rate gains only with flaps up and 80/85/90 with flaps deployed as theoretically I'm flying a lot slower with flaps down and therefore there is no oscillation with high rate gains and flaps.

Have someone at your local club who knows these receivers help you program it if possible, however, it really is quite easy to program directly off of your TX and HH has some good tutorials. Since you have an 8 channel TX, you will be able to program the receiver with adjustable gains while flying and with SAFE, if you like (each assigned to a separate knob and switch). Spektrum's RX's internally have a lot more channels than just what is listed. The 6, 8 or 10 channels of their 3 AS3X receivers actually refer to the number of ports you can plug in, but I was told internally they have something like 20 channels (don't ask me to explain this, I just go with the flo). So the F-4 needs a minimum of 6 plug in channels, Throttle/aileron/elevator/rudder/gear/flap. To get adjustable gains, you need a 7th channel (in the TX) and to program SAFE that would be the 8th TX channel. For example, if you had only a 6 channel TX, your gains would be fixed and you would be unable to assign that to a separate knob to adjust in the air. Conversely, if you had a 9 channel TX, you could actually program separate adjustable gains on the ailerons (7th channel) elevator (8th) and rudder (9th) but then couldn't also program SAFE to a separate switch (10th channel). Of course with an IX 20, you could program all kinds of stuff not requiring a plug in port even with a 6 channel RX.

Sorry I have mouth diarrhea today, but hope this helps just a little bit.

Speaking of Homestead AFB:

[GliderGuy]

Others may chime in and suggest a good first EDF to build flight skills BEFORE you fly the F-4.

These birds are fairly easy to assemble.

Before you begin assembly, take the time to read ALL the posts in this forum. Yep…All 259ish. It will be worth your time. Lots of knowledge here. And, some beefing up in the tail is needed.

Loved your history lesson. Thanks.

Many EDF jets can go 4-5 minutes. But look at it this way….short flights = more flights = better landing skills developed.

Also, don’t shy away from the F-4 when the time comes. She’s a lot of fun to fly…and looks great in the air.

-GG

[Habukeeper]

Hi gliderguy,

Thanks so much for the advice and the link for the battery. I will most definitely avail myself of that knowledge and one or two of those batteries. Your advice was exactly what I was hoping for. It’s always been my experience that the RC community are some of the best. As for my EDF experience it is exactly as I’m sure my post would imply. Nonexistent. Lol. 😀. I do however plan to get there before I throw sticks on that beautiful model. I do think my modeling skills are equal to the task for assembly. I plan to deck it out in the livery of the 31 TFW 309th blue amu out Of Homestead AFB. You see my best friend of 40+ Years passed away last year. We were both fighter crew chiefs at Homestead and John was actually the assigned dedicated fighter crew chief for acft 463 which the model is well, modeled after. I hadn’t planned on getting an EDF because of the short flight times and the skill I know is required to avoid that pile of styrofoam you talked about. I was also an SR-71 crew chief ,hence the name Habukeeper, and am currently making my way towards retirement from 31+ years in the commercial aviation industry as a A&P tech. I always found it a bit ironic that the real jets were easier to keep air worthy than my models. RC planes have sure changed a great deal since the late 70s. Ok enough of the history lesson. I bought that jet to build in honor of my bud so I’ll do my best to keep it in One piece as long as possible. It may be awhile before I get to fly her but I can wait. I’ll figure out which receiver is best for the spektrum radio and the Phantom. Sorry for the lengthy post. I thought maybe a bit of background might let you know the phantom will be in good hands and I have a pretty good idea of what I’ve gotten myself Into, further research is in order. Lol. I loved that “tiger by the tail” comment, btw. That perfectly describes what I expect. Talk to you later.

[GliderGuy]

Hi Habukeeper,

Assuming you have the SPMX70006S30 battery …..which is listed with the Draco;

The F-4 with this battery will likely be sucking wind and may run too high of a battery temperature. If you operate off grass, she may not get into the air without a LONG run.

Battery weight and lower C rating of this battery are gonna be fighting against you. Best consider SMC batteries for the F-4. Example:

https://www.smc-racing.com/index.php...product_id=604


I use Futaba radio gear, so can’t help there.

ESC consideration is voltage….not battery capacity. 6S LiPo is for the F-4 ESC. Battery capacity will influence: weight, size, and time in the air. This bird needs a high C rating (that is a true C). With the above SMC battery….about 3 min flights with throttle management which will leave reserves for go-arounds and will allow for some hot-rodding and acrobatics. Note: Flight times are subjective….just wanted to make sure your mindset is for SHORT flights and not Draco-like times.

Suggest you read some of the many good articles on the SMC website and learn more.

Hugh is smiling

What is your EDF jet experience? If you are jumping from a Draco background to this EDF jet, you are gonna feel like you have a tiger by the tail. Best leave the maiden to an experienced EDF jet pilot if you do not have EDF jet experience.

CAUTION: The F-4 is not a beginner EDF. There are better EDF jets that you can transition from and then get to the F-4. To go from a Draco to the F-4 you may be at risk of going from a bird with trainer-like, high-wing handling characteristics to having a pile of foam pieces within a few seconds.

-GG