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Old Dec 27, 2010, 01:39 AM
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Starmax F-4 Phantom 90mm Build Thread

Hello Pilots,

First of all I hope that everyone had a very nice christmas eve and a nice time to relax

I pulled the Trigger on the F-4 Phantom 90mm Jet V2 for myself as a Christmas Present.

Now I was looking through search to find anything about this Aircraft...but could not find anything but the BH Thread..

I heard rumors that the F-4 is a very hard to fly Aircraft, apparently there is to much lift generated by a misconstruction of the Wing Design?

The Full Moving Elevator seems to be also a Problem since the 9 gram servo may not be as strong, which will be replaced by a powerful 4kg torque Turnigy Metal Gear Servo.

Does anyone know this plane, how does she fly?
What is the correct alignment of the elevator's?

I am looking into some Information, to gather them so I know if the Plane needs any mod's at all.

I would welcome any ideas, suggestion's or just information about this plane

Best Regards

Neversommer.
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Old Dec 27, 2010, 03:46 AM
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Ballarat, Victoria, Australia
Joined May 2004
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I think the general opinion is that the FlyFly 90mm Phantom was/is the better kit, both in terms of scale and flying. The single 9gr servo for the elevator was a downright stupid design by Starmax and I know of at least 3 Phantoms that crashed due to this (in all fairness they were inexperienced pilots, more experienced ones modified this before flying). In fact I bought myself a FlyFly one for Christmas (my 70mm one flies so nice I had to get a bigger one), almost bought a Starmax one a few months ago off ebay but the price was just too high considering I had to modify it to get it to fly. With some work they can be a nice flying machine.
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Old Dec 27, 2010, 04:04 AM
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Quote:
Originally Posted by Frenche View Post
I think the general opinion is that the FlyFly 90mm Phantom was/is the better kit, both in terms of scale and flying. The single 9gr servo for the elevator was a downright stupid design by Starmax and I know of at least 3 Phantoms that crashed due to this (in all fairness they were inexperienced pilots, more experienced ones modified this before flying). In fact I bought myself a FlyFly one for Christmas (my 70mm one flies so nice I had to get a bigger one), almost bought a Starmax one a few months ago off ebay but the price was just too high considering I had to modify it to get it to fly. With some work they can be a nice flying machine.
I believe the only real major modification on this plane should be the elevator servo to be replaced.

Like I said I would be using a 4kg torque metal geared servo for the elevator to work.

Landings need to be coming in a bit fast otherwise you loose control.

Fact is, I talked to Aero-Tech and changed my F-4 to a Starmax Alpha Jet to be on the safe side on things.

I kinda like the F-4 Phantom a lot more in Design and looks..it just looks a lot more aggresive then an Alpha Jet.

The Retracts are not the best either in the world...the ones from the alpha are a bit stronger..

Jeez I hate decisions

I am just afraid, since no one really has it..and the Flyfly needs a modifcation to be made on the wings to fly really straight..I may never get a F-4
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Old Dec 27, 2010, 04:24 AM
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Ballarat, Victoria, Australia
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Yep the FlyFly one needs ailerons added to fly well but since I'm planning to glass it it's not that much extra work. Also I seem to remember something about the elevator pivot rod in the Starmax one not being good enough, I heard that the collet had a tendency to slip on the shaft but I could be wrong. I hear you on the Alpha Jet, I have the Starmax 64mm version sitting in a box and whilst I do like the looks, the Phantom is just so much meaner.

If you want an F-4 look into the 70mm one that hobby king has http://www.hobbycity.com/hobbyking/s...dProduct=14433 it flies pretty well on the standard fan and motor. Not sure how good the included servos are as I bought mine over a year ago from a different vendor as a airframe only with fan and motor. Hand launches easily and will fly for 5min on a 4s 2200 30c pack but I would recommend a larger battery as I had to install mine several inches further forward, in fact it ended up right on top of where the nose gear would have been. Also the nose cone is VERY thin plastic, mine is trashed after only 10 flights
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Old Dec 27, 2010, 04:32 AM
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Originally Posted by Frenche View Post
Yep the FlyFly one needs ailerons added to fly well but since I'm planning to glass it it's not that much extra work. Also I seem to remember something about the elevator pivot rod in the Starmax one not being good enough, I heard that the collet had a tendency to slip on the shaft but I could be wrong. I hear you on the Alpha Jet, I have the Starmax 64mm version sitting in a box and whilst I do like the looks, the Phantom is just so much meaner.

If you want an F-4 look into the 70mm one that hobby king has http://www.hobbycity.com/hobbyking/s...dProduct=14433 it flies pretty well on the standard fan and motor. Not sure how good the included servos are as I bought mine over a year ago from a different vendor as a airframe only with fan and motor. Hand launches easily and will fly for 5min on a 4s 2200 30c pack but I would recommend a larger battery as I had to install mine several inches further forward, in fact it ended up right on top of where the nose gear would have been. Also the nose cone is VERY thin plastic, mine is trashed after only 10 flights
I know what you mean. The elevator is the biggest issue on the F-4 from Starmax.

I will stay with the Alpha and see how she turns out.

One day I get the F-4 and do the necessary mods for it.

Right now I just have a lot of other things to get sorted out

And for 400bucks, the F-4 is just a bit to much for what she is.

The Alpha is with 330Bucks a bit cheaper.

I want retracts on the birds..otherwise I just cancel them straight away.
I have seen the 70mm F-4, but since it has normal gear..it's a no go for me.

I still have an F-18 from Starmax to get ready again and a Mirage 2000.

An 3665 Arc/Wemo Combo is also on the way with some serious thrust.

Maybe the Alpha will be the one to get this bird tested on

Neversommer.
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Old Dec 27, 2010, 06:25 AM
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Ballarat, Victoria, Australia
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I didn't bother with the gear on the 70mm F-4, just hand launch/belly land, I save retracts for 90mm and up planes as the 70mm ones wheels are generally too small to work from the grass fields I have access to.

That ARC/Wemo combo should be a killer setup, 2.2kw and 3.5kg of thrust should make for a sweet flier. Personally with my Phantom I'm going a ARC 3655-2 1400Kv on 8s in a midifan, a bit less power (around 2kw) but lower amp draw so I should get nice long flights out of 4000mah packs
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Old Dec 27, 2010, 07:07 AM
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Originally Posted by Frenche View Post
I didn't bother with the gear on the 70mm F-4, just hand launch/belly land, I save retracts for 90mm and up planes as the 70mm ones wheels are generally too small to work from the grass fields I have access to.

That ARC/Wemo combo should be a killer setup, 2.2kw and 3.5kg of thrust should make for a sweet flier. Personally with my Phantom I'm going a ARC 3655-2 1400Kv on 8s in a midifan, a bit less power (around 2kw) but lower amp draw so I should get nice long flights out of 4000mah packs
Let me know how you go with your Phantom, I really want to see one flying

I think the 3665 Arc/Wemo combo may could be a bit of an Overkill for the Alpha, since the stock setup already makes this Bird scream.

The Plane has been send out today and should be arriving by around Wednesday or Thursday.

I will make a Video to show my latest Addition to my Fleet.

The F-18C from Starmax and the Alpha Jet are in my PulseSonic Fleet, meaning for Top Speed.

Let's see how it turns out

Neversommer.
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Old Dec 27, 2010, 09:09 AM
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I am not sure but I am now still not very happy with my decision to take the Alpha Jet over the F-4 Phantom
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Old Dec 27, 2010, 11:19 AM
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My experience with the SM F4 is better than expected, I crashed twice because of the tail but the foam didn't snow up on my to the point where I couldn't put it back together. The 3rd time I put a flat spot on the tale rod AND epoxied it....seems to have worked. I also twinned it up with 2 64mm hoaye fans in the rear nacelles and since the model is light it flew with decent speed and sounded pretty kewl.

I now fly it with a 21 dollar himodel 1700 kv motor on the wemo knock off fan and can go vertical with it beyond my comfort level on 7s with the HK 7s esc.

Also, it's 212$ shipped from BH radio ready but I would buy it without their electronics...the KDS motor is the only thing worth having it there radio ready model. You can get your own electronics from HK and have a better model.

The Fly Fly model is a better design though and I like the quality of FF kits BUT...the FF foam is more stiffer and not as forgiving as the Starmax.

FYI.....The FF model is 15 skins less than the SM model at EDFHobbies.com...
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Old Dec 27, 2010, 01:52 PM
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Originally Posted by erh7771 View Post
My experience with the SM F4 is better than expected, I crashed twice because of the tail but the foam didn't snow up on my to the point where I couldn't put it back together. The 3rd time I put a flat spot on the tale rod AND epoxied it....seems to have worked. I also twinned it up with 2 64mm hoaye fans in the rear nacelles and since the model is light it flew with decent speed and sounded pretty kewl.

I now fly it with a 21 dollar himodel 1700 kv motor on the wemo knock off fan and can go vertical with it beyond my comfort level on 7s with the HK 7s esc.

Also, it's 212$ shipped from BH radio ready but I would buy it without their electronics...the KDS motor is the only thing worth having it there radio ready model. You can get your own electronics from HK and have a better model.

The Fly Fly model is a better design though and I like the quality of FF kits BUT...the FF foam is more stiffer and not as forgiving as the Starmax.

FYI.....The FF model is 15 skins less than the SM model at EDFHobbies.com...
Hihi,
I spoke to the guy tonight again and changed the Jet from the Alpha to the F-4.

I will make the flat spot as well and epoxy it in place. Over the rod I will put a carbon tube to make sure it won't flex

I just hope the retracts will be able to carry the weight of a 1kg battery.

Any suggestions otherwise? LOL
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Old Dec 27, 2010, 03:20 PM
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Quote:
...I will make the flat spot as well and epoxy it in place. Over the rod I will put a carbon tube to make sure it won't flex ...
Don't forget to tape the ends of the tube also to keep them from fraying

Quote:
...I just hope the retracts will be able to carry the weight of a 1kg battery...
What kinda battery?

Also, I fly this with a 6 channel rx and I can put all my radio gear plus the ESC in the top compartment of the fuse leaving the battery area open for options but I've not gone over a 7s 3700.
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Old Dec 27, 2010, 06:52 PM
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Ballarat, Victoria, Australia
Joined May 2004
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Couldn't resist the Phantom ?

1kg of batteries? What packs are you planning to use? 4s 4000mah 20c packs weigh 437gr each (so 874gr for 8s), 30c packs weigh 452gr (so 904gr for 8s) and 40c packs weigh 476gr (so 952gr for 8s) so I'm surprised to hear that yours will be over 1kg as mine (at worst case) should only be around 960gr. A 6s 5000mah 40c pack only weighs 863gr and that should have enough power to run your setup comfortably. According to Mark at extreme rc that combo puts out 2200watts so if we assume in a perfect world 2200 / (4.2*6) = 87amps. Now I agree the cells wont hold 4.2v under load so your more likely looking for the amps to be around 95 but that's still well within even a 30c packs range.

If we do the same with an 8s setup using the combo I chose which puts out around 2000watts we get 2000 / (4.2*8) = 60amps. Again take into account voltage sag I should be up around 70amps which means I can get away with a 80amp ESC. I'm hoping that this lighter ESC (you would need at least 100amps, probably more to be safe) and the lighter motor (250gr for mine vs 300gr for yours) I can come out to close to the same weight as your setup.

Anyways their is no right or wrong setup, it's all about choice, there is more than 1 way to skin a cat as they say. Your setup has the advantage of being lower weight and a 6s batt is 'low voltage' meaning most chargers can handle 6s packs and you won't need a dedicated HV ESC which are more expensive than a LV one. Disadvantage (well for me at least) is the high amp draw. Mine has the advantages of lower amp draw and lighter motor, but the disadvantages of higher weight, needing a HV ESC ($$$) and charger. I can get around the HV charger by using 4 cell packs wired in series but then they take twice as long to charge (my charger will only do 6s max).

Some quick HK surfing come up with this ESC for your setup (overkill I know but at least you wont over-amp it, price is pretty good too)
http://www.hobbycity.com/hobbyking/s...idProduct=8920
and this one for mine (couldn't find a 80amp one and I didn't feel comfortable with 70amps so this one is overkill but again I wont over-amp it)
http://www.hobbycity.com/hobbyking/s...idProduct=4691
It looks like ESC price and weight is about the same which surprised me (I found an 80amp HV one on ebay for a few $$ less, same weight though), in theory you could use the same 100amp HK ESC as I found but it wont give you much overhead protection if the numbers I guestimated for amp draw are wrong.

I'm looking forward to seeing how your setup works out
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Old Dec 28, 2010, 04:46 AM
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I had a chat with Mark and there are issues with Turnigy Batteries which my friend got to feel the hard way.

He has a MIG-29 with 2x90mm Fans, each fan pulling a good 50-55amps..so a total of 100-110amps.

He is using a single Turnigy 40c 5000mah battery.

He can do a good 2-3 high speed passes for around 10-15 seconds and flies the rest on half throttle.

Flight time around 4 minutes.

Battery comes in very hot and needed to be thrown away after 13 chargers, lost power and also puffed up very badly.

I am now using a Hyperion 35c 6500mah 6S Battery which should due to the high power density pull out a good 2400watts power on my 3665 setup, that is a good 200watts more then advertised.

Hyperion are one of the best batteries out there and for Jet's surely on the the best choices. Yes they cost more..but if you buy 2 or 3 5000mah 40c turnigy batteries which can be thrown in the bin in a very short time..you lost quite a bit of money there for nothing.

I am now ordering a Hyperion 6500mah G3 Vx 35c battery which should provide 227amp continous power.

The battery costs me 230dollars..but should be well worth it.

Here are the details:

http://www.rcdude.com/servlet/the-14...X--dsh-/Detail

Weight is 1011 grams.
Dimensions are pretty pretty nice comparing it is massive 6500mah battery.

Flight time should be easily extended for a minute or 2.

The most Important thing is..I will be able to dish out with my Arc/Wemo combo, more power then desired

Should do the Job hopefully well.

I just hope these cheap retracts will hold up on that weight.

I am using a K-Force 120amp's Esc 6-12s HV to power this beast.
6mm Golden Bullet Connectors will sort out the power coming from the battery to the Esc.

I am thinking of Electric Retracts, but I can't yet find anything that may fit this Jet!

I want this F-4 to Scream through the skies..

This Servo should handle the full moving elevators:

http://www.hobbycity.com/hobbyking/s...idproduct=8760

I also have this Servo at hand which is bigger and heavier, but less torque:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idproduct=6446"

Let me know if that will be enough for the Elevator

Neversommer.


This F-4 should be in my High Performance Fleet..let's see if the lives up the Hype

Ps: Yes I could not resist the Phantom despite it's "bugs".
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Old Dec 28, 2010, 08:23 AM
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Those Hyperion batts sure are nice, but I just can't justify the expense. I've never had a problem with Turnigy or Zippy Flightmax packs (have at least 20 floating around in various sizes) but that doesn't mean they are all good. I use them within their specs and make sure the have good cooling, they come down warm but not what I would call hot (can easily wrap your hand around them without any discomfort) and only fly till around 3.7v per cell meaning quick recharge times, maybe I have just gotten lucky so far though.

Those servos do look nice, I was thinking either MG-14s or MG-16s or a combo of both but those Turnigy 380MAX servos look pretty good, not that expensive either.

For electric retracts take a look at the bigger of the HK 'generic' ones, no nose gear listed but you should be able to modify a normal one to provide steering. They take 5mm struts and have a nice large mounting footprint so should take the abuse from large jets flying off grass fields.
http://www.hobbycity.com/hobbyking/s...dProduct=14838

That ESC will work a treat, I have the 70A one in my HK600GT running 12s 3000mah 40c packs and it doesn't even get warm (ok I can only hover and very slow forward flight but still).
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Old Dec 28, 2010, 08:49 AM
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Originally Posted by Frenche View Post
Those Hyperion batts sure are nice, but I just can't justify the expense. I've never had a problem with Turnigy or Zippy Flightmax packs (have at least 20 floating around in various sizes) but that doesn't mean they are all good. I use them within their specs and make sure the have good cooling, they come down warm but not what I would call hot (can easily wrap your hand around them without any discomfort) and only fly till around 3.7v per cell meaning quick recharge times, maybe I have just gotten lucky so far though.

Those servos do look nice, I was thinking either MG-14s or MG-16s or a combo of both but those Turnigy 380MAX servos look pretty good, not that expensive either.

For electric retracts take a look at the bigger of the HK 'generic' ones, no nose gear listed but you should be able to modify a normal one to provide steering. They take 5mm struts and have a nice large mounting footprint so should take the abuse from large jets flying off grass fields.
http://www.hobbycity.com/hobbyking/s...dProduct=14838

That ESC will work a treat, I have the 70A one in my HK600GT running 12s 3000mah 40c packs and it doesn't even get warm (ok I can only hover and very slow forward flight but still).
The Servo's are very nice and very powerful

I reckon the 4kg torque should be enough for the F-4, what do you think?

I now ordered the freewing Eurofighter Complete Retracts, should fit the F-4 Phantom's Design nicely

I ordered also the 6500mah Hyperion Battery including the necessary 550watt power hyperion charger.

I spend today now a good 900Dollars on stuff for my Projects now and 2011

Neversommer.
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