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Old Jan 18, 2013, 02:07 AM
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The43rdHammer's Avatar
United Kingdom
Joined May 2010
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Hi Guys, some video below (quality isn't great but the camera just wasn't up to the job, hopefully thats's now resolved):

FMS F-4 Phantom - Andy Smith - 23 December 2012 (Flight #1) (2 min 54 sec)



FMS F-4 Phantom - Andy Smith - 23 December 2012 (Flight #2) (3 min 59 sec)


The video doesn't fully do it justice but will give you some idea of the end result.

That 1W-40 sounds like a goer , if you've got the batteries to hand I would try on 5s first, then 6s once you've got it trimmed and happy with the throws etc. Remember you'll be cutting your flight times down drastically pulling that power.

Andy
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Last edited by The43rdHammer; Jan 18, 2013 at 02:15 AM.
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Old Jan 18, 2013, 10:17 AM
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Joined Dec 2008
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It'll be 5 S only , 6S would blow up my 6904 , plus ill be using a 4400 mah gens ace 65 -130 c and that's about as big a battery as I could possibly fit. One day when I get a Jet with more wing area I'll go for the 6S .Cool vids by the way
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Last edited by pencon; Jan 23, 2013 at 10:08 PM.
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Old Jan 20, 2013, 09:30 AM
Why am I addicted!!!
DonQ8401's Avatar
United States, IL, Columbia
Joined Jan 2008
553 Posts
Pencon, Are you familiar with HET75 AMP ESC? I am having issues with it. Need some assistance. I have a 6904 Han a 2w-20 motor and ran it on 4 s and was showing around a 1000 watts and 75 AMPs. Why is it so high? It should be that high...
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Old Jan 20, 2013, 11:16 PM
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Joined Dec 2008
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Yeah Don I have the same setup but I never really measured it when It was up and running .Your esc should handle that no problem though . You should also buy a programming card for that ESC . It's a manual programmer so you can even use it at the field.
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Old Feb 04, 2013, 07:05 PM
FLY HARD OR FLY HOME TO MUMMY
jb0005's Avatar
Joined Jan 2011
195 Posts
just finished test flying my 70mm f4 from hobby king. as you probably all know it is the same f4 that is sold as the airfield f4, hobbylobby f4 and fms f4. I will give as much detail as possible in an effort to stop people having to trawl through pages of posts to gather all the information that i gathered before test flying mine and post this on the other main thread on this jet...here goes..

mine is set up with max throws on all surfaces and 40% expo on both ailerons and elevator, and this makes it a pussy cat. excellent roll rate without being twitchy, plenty of elevator when you need it without being sensitive in the flare.
Cg is set at 148mm. initial test flight was at 138mm and this more forward cg is not necessary.
battery i use is either a 2200 4s 20 or 2200 3s 25c
the motor and fan i have put in it is the following

http://www.hobbyking.com/hobbyking/s...on_4000kv.html

with my plane weighing 966grams with the 4s battery this gives more than enough power to lift vertically out of your hand and so vertical performance is unlimited. with the 3s battery this is obviously not possible but still nice to fly.

now to the most important part..thrust line. if you must try flying the plane without carrying out the following thrust nozzle mod DO NOT launch at full power (i used 1/2 with my power 4s set up) and Do NOT throw the jet at any more than 10degrees up angle or it will pitch up and be very hard to recover, especially if you are only using small throws on your controls. if you hold the jet vertical by the nose and apply full power you will notice that the jet pulls toward its belly. to fix this the nozzles need to be cut off and pointed down 3 or 5 degrees. i initially tried cutting off 3mm at the bottom(incidentally this is also 3 degrees as the nozzles are 60mm in diameter..1 in 60 rule for those with navigation knowledge!) and this made the jet stay vertical when i tested again. when i test flew it though there was still a pitch up on launch and when throttling up from low airspeed. better, but not perfect..
so i cut them off again and took another 2mm off the bottom and retested while holding it vertical by the nose(just taped them on temporarily this time). this time it pushed the opposite way, toward the top of the plane. i thought i had over done it, so i taped them on nice and secure and test flew it..perfection..full power launches, no pitch up at all through out the speed range.
the other thing that this bad thrust line effects is trim changes and the apparent behaviour of the aircraft. for example, if the plane is trimmed to fly at half throttle with the nozzles in their original position, when power is taken away the nose drops quite markedly, giving the impression that the plane doesn't glide and needs power on the approach. this is occuring because the very thing that is helping it fly hands off at half throttle when trimmed (the off centre thrust that is)has been been taken away. if you then apply back stick to correct for this the plane floats in as good as anything else for the most gentle of landings. the other strange thing it will do , is if you go vertical on full power for a while , pull over the top and start heading back down vertical with the power off, the plane will want to tuck under, because the forwad trim that has been added when trimmed at half throttle to counteract the bad thrust line is no longer needed, so once again the nose goes down quite markedly, or in this case starts to tuck under. for someone inexperienced to have this occur to them, their reaction would probably be to reef back on the stick when they see it tucking under and high speed stall the plane.
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Old Feb 05, 2013, 07:10 AM
4 blades! Scale blades!
Tartago's Avatar
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JB

I was looking the real thing and noticed the alignment of the nozzles with the curve of the fuse. Well done!
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Old Feb 05, 2013, 11:30 AM
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Crawley Down, sussex, England
Joined Dec 2004
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Jb005- nice evaluation. I have to agree, as I learnt that lesson the hard way with multiple hair raising hand launches. I now take off on the belly tanks, which is much safer.
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Old Feb 06, 2013, 12:50 AM
FLY HARD OR FLY HOME TO MUMMY
jb0005's Avatar
Joined Jan 2011
195 Posts
mine hand launches like a pussycat now at full power(under hand throw). i was talking with a friend of mine today who had a fly fly 90 mm f4 and he also said he had the same pitch up problem. anyway.. hope the write up helps someone.. by the way nice photos sniper.. here's one i took of something i went for a fly in yesterday...its for sale...what do ya reckon?
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Old Feb 09, 2013, 12:39 AM
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denver colorado
Joined Jan 2004
354 Posts
Did you have to add up- elevator trim after you changed the nozzle angle?
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Old Feb 09, 2013, 04:26 PM
FLY HARD OR FLY HOME TO MUMMY
jb0005's Avatar
Joined Jan 2011
195 Posts
very little, maybe 3 clicks and that was only because of the forward trim i originally had put on due to the nozzles original position. the elevators are pretty much in line with the tailplane with the new nozzles
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Old Feb 09, 2013, 05:28 PM
Aaron
Realms's Avatar
Australia
Joined Aug 2012
1,740 Posts
Hi Guys

This will be my first EDF after 12 months of learning to fly. I can fly the large 1.4 FMS Mustang with no worries and am craving more speed. Is this a good EDF to start with?
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Old Feb 09, 2013, 09:08 PM
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Rangerfan's Avatar
United States, TX, Grapevine
Joined Jul 2012
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Quote:
Originally Posted by Realms View Post
Hi Guys

This will be my first EDF after 12 months of learning to fly. I can fly the large 1.4 FMS Mustang with no worries and am craving more speed. Is this a good EDF to start with?
Kinda depends on how you plan to set it up. Gear or hand launch? Plan on 4s or bigger battery? Read through the thread and you'll be prepared.
I started with a fairly slow setup and hand launch. Learned quickly that I needed the thrust nozzle mod to prevent the high alpha launch. Then went back to fixed gear and added a better fan motor and ESC and needed a bigger battery. As you add weight to improve performance, it lands much faster. Then added flapperons and rudder to improve turns and landings. Finished it off with retracts.
Now, she's really fat. Lands fast even with flaps. But, a lot of fun to fly.
Probably not the easiest jet to start with but certainly do-able.
In turns, speed is your friend. If your phantom is heavy, you'll need speed to land.
Probably the single most important mod I'd suggest is the thrust nozzle mod.
Good luck!
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Old Feb 10, 2013, 02:42 AM
Aaron
Realms's Avatar
Australia
Joined Aug 2012
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Quote:
Originally Posted by Rangerfan View Post
Kinda depends on how you plan to set it up. Gear or hand launch? Plan on 4s or bigger battery? Read through the thread and you'll be prepared.
I started with a fairly slow setup and hand launch. Learned quickly that I needed the thrust nozzle mod to prevent the high alpha launch. Then went back to fixed gear and added a better fan motor and ESC and needed a bigger battery. As you add weight to improve performance, it lands much faster. Then added flapperons and rudder to improve turns and landings. Finished it off with retracts.
Now, she's really fat. Lands fast even with flaps. But, a lot of fun to fly.
Probably not the easiest jet to start with but certainly do-able.
In turns, speed is your friend. If your phantom is heavy, you'll need speed to land.
Probably the single most important mod I'd suggest is the thrust nozzle mod.
Good luck!
Thanks for the info Rangerfan. The version I am buying is without a motor so I am not sure what the RTF version comes fitted with? I plan on buying this motor and fan http://rc-castle.com/shop/product_in...roducts_id=779 and running it off a Turnigy Plush 60amp esc. I'll just stick with 4S 2200's to begin with. I am hoping it will take off from short grass as I have never hand launched any large models.... scared I would lawn dart it Is it neccesary to cut off the nozzles and re-angle?
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Old Feb 10, 2013, 01:55 PM
Scale Jet Driver
Rangerfan's Avatar
United States, TX, Grapevine
Joined Jul 2012
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Quote:
Originally Posted by Realms View Post
Thanks for the info Rangerfan. The version I am buying is without a motor so I am not sure what the RTF version comes fitted with? I plan on buying this motor and fan http://rc-castle.com/shop/product_in...roducts_id=779 and running it off a Turnigy Plush 60amp esc. I'll just stick with 4S 2200's to begin with. I am hoping it will take off from short grass as I have never hand launched any large models.... scared I would lawn dart it Is it neccesary to cut off the nozzles and re-angle?
I think it is. Even on the runway , it would go nose up violently and quickly. I'd suggest modding them.
I went to recover from an aborted landing and it went almost 90 degrees up when I hammered the throttle. I did the mod the next day.
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Old Feb 10, 2013, 06:05 PM
4 blades! Scale blades!
Tartago's Avatar
Joined Apr 2006
4,360 Posts
If you take care of doing a smooth take off, the nozzles can be left alone.

The stock plane motor was powerful enough to go to the air in less than 5 meters.

During the flight, however, avoid sudden acceleration after a slow turn because the plane tends to go high alpha and stall.

After 100+ flights the stock motor died and I replace it with a 10 blade EDF and a 2855 2100kv motor on 5s. Now it's a blast!

I'm doing another with the new 12 blade EDF.
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