Official Freewing 90mm F-15C Eagle Thread

[gooniac33]

This was tested in the plane. Not a true measurement since I only have acces to a kitchen scale and I only wanted to see what the fms put out. I’m going to try the original hp version fan. I’m just disappointed in the performance in this f15. She seems to drag it’s butt all day long, while my f14, l39, Avanti, 70mmf18, f16 move in a more authoritative way. If that makes sense.

It is a draggy bird. It won't really be faster with the FMS set up but will be lighter and fly better all around.You can get it to move pretty good though if you get the right combo.If you want faster then you need to go another route. Either 8s or the higher performance 6s set ups that we have been using. Have you seen any of my videos? Here are some from last weekend... We have a ton of fun with it last weekend! Our goal with the set ups we used was to get much better than stock performance but using the same batteries that you would use stock. So I am using a 6s 55c 5000 China Hobby Line pack or Turnigy Heavy Duty 6s 60c 5000mah pack. There are some other packs I will be getting soon that are 6000s and 6500s. 3-6min flight times with our set ups with huge increase in performance as well... take a look...

Now this video is not the F-15 but my other friend uses the same set up that is in this F-4 in his F-15 and it made it a rocket ship. He ca get 5 min flights with throttle management but it still flies jet like at lower settings!!

[RCjetdude]

This was tested in the plane. Not a true measurement since I only have acces to a kitchen scale and I only wanted to see what the fms put out. I’m going to try the original hp version fan. I’m just disappointed in the performance in this f15. She seems to drag it’s butt all day long, while my f14, l39, Avanti, 70mmf18, f16 move in a more authoritative way. If that makes sense.

I know what you mean. I retired my Stinger 90 with JP 8S fan and Castle Talon ESC which in that plane was a sweet combination. Thought it would make an F-15 perform great but it did not live up to my expectations. It flies good but it is just a different airframe. Obviously more draggy and heavier. I think more of it has to do with wing loading too.

[Rcfiddy1]

This was tested in the plane. Not a true measurement since I only have acces to a kitchen scale and I only wanted to see what the fms put out. I’m going to try the original hp version fan. I’m just disappointed in the performance in this f15. She seems to drag it’s butt all day long, while my f14, l39, Avanti, 70mmf18, f16 move in a more authoritative way. If that makes sense.

[RCjetdude]

Fan ratings much of the time are determined on a bench tester not in a duct which will reduce overall performance. Are you testing in an actual plane?

[gooniac33]

I’ve been following these f15 tests and wanted to share my results with the fms 90mm 12 blade 1900kv fan upgrade. Aircraft weight with fms fan 2443g w/o battery.

Here are my numbers.

5200mah Zeee 50c pack
low timing 112amps 2236g thrust
mid timing 115amps 2300g thrust
high timing 126amps 2330g thrust

5000mah 70c chinahobbyline
low timing 125a 2450g thrust
mid timing 127a 2465g thrust
high timing 130a 2540g thrust

All amp results are peak amps and they usually drop off.

I don’t see how the manual says 4300g thrust.. Even fms says that the fan should push 3.26kg thrust @112 amps. Now I understand that it’s not getting any air pushed into intakes and my kitchen method is flawed. But really 4300g stock?

throttle calibration may not have been done... that sounds way less than what I have seen before. The plane may not be all that much faster but will fly better all around. Half throttle amp draw is way down from stock but it still moves much more air. When I switched out to this fan in the F-104 it helped in all ways. I gained 1 min flight time since less throttle was required to keep it in the air. Also its a momentum plane! Get it going and man it will really scream!

[DCORSAIR]

I’ve been following these f15 tests and wanted to share my results with the fms 90mm 12 blade 1900kv fan upgrade. Aircraft weight with fms fan 2443g w/o battery.

Here are my numbers.

5200mah Zeee 50c pack
low timing 112amps 2236g thrust
mid timing 115amps 2300g thrust
high timing 126amps 2330g thrust

5000mah 70c chinahobbyline
low timing 125a 2450g thrust
mid timing 127a 2465g thrust
high timing 130a 2540g thrust

All amp results are peak amps and they usually drop off.

I don’t see how the manual says 4300g thrust.. Even fms says that the fan should push 3.26kg thrust @112 amps. Now I understand that it’s not getting any air pushed into intakes and my kitchen method is flawed. But really 4300g stock?

I stuck the same unit in my F-15 and it actually felt slower to me and flight times were not any better than my 1680kv, so I went back to the 1680kv, way better, just tried it for fun, I never checked the timing or anything but I wasn't impressed after several flights.

[Rcfiddy1]

I’ve been following these f15 tests and wanted to share my results with the fms 90mm 12 blade 1900kv fan upgrade. Aircraft weight with fms fan 2443g w/o battery.

Here are my numbers.

5200mah Zeee 50c pack
low timing 112amps 2236g thrust
mid timing 115amps 2300g thrust
high timing 126amps 2330g thrust

5000mah 70c chinahobbyline
low timing 125a 2450g thrust
mid timing 127a 2465g thrust
high timing 130a 2540g thrust

All amp results are peak amps and they usually drop off.

I don’t see how the manual says 4300g thrust.. Even fms says that the fan should push 3.26kg thrust @112 amps. Now I understand that it’s not getting any air pushed into intakes and my kitchen method is flawed. But really 4300g stock?

[purduephigam]

I will try the 5000s and see if there's a difference in character. Tempted to try that outrunner as well. Thanks for your input!

[C17loadmaster]

I have the Inrunner version too and I use 5000’s. My timer is set at 3:15. Mine also has the weight in the nose. It flies awesome on 5k’s. I most definitely do not fly past the timer. I ran a battery out the first couple times I flew it. I was flying pretty hard on the throttle. I managed to make a “good” dead stick landing. They drop like a rock without power on landing, and I broke the MLG doors off. Overall I think it’s one of Freewings best airplanes. The landing gear is rock solid and the CG is really forgiving. I bought one of the new FW 90mm outrunners that I’m going to use. It weighs 145g less and produces similar thrust than the 1650 Inrunner does... it’s on my list of projects

[purduephigam]

Maidened my F15 today. After conversing with Steve, it is most definitely an inertia flyer. Still needs some adjustments but otherwise super cool in the air. I bought the high performance version so I am adhering to a strict 2:30 flight time.

I am running it with a 6250 pack and had to counter balance with 2oz of weight in the nose. I'm wondering if it'll be more efficient if I remove the counter weight and just balance with the 5000 packs. Anyone have any experience with this? I'm thinking this type of plane would respond more favorably to less weight rather than a larger pack (with the idea of getting more flight time)

[seaviper]

Copy that.

[C17loadmaster]

When is motion planning on getting F-15 gear struts back in stock?

I just bought some from RC Castle. They took about a week to get here from China.

[seaviper]

When is motion planning on getting F-15 gear struts back in stock?

[seaviper]

Every jet I fly off grass takes off better with 1/2 flaps than with no flaps. Also, use a healthy amount of back pressure on the takeoff roll to lighten that nose wheel. If you can get the nose wheel up a little she will accelerate better. In grass, lighter birds fare better than their heavier counterparts.

[RuthR720]

I test flew my F-15 with the 9-blade power system and it sounded great and had plenty of power. It’s the same power system as installed in the stock F-4 Phantom. I just need to move the battery aft and mix some up elevator with the flaps on my next flights.

https://youtu.be/grf4rVnlI8Y

[Jet10]

I fly my inrunner off grass but the grass must be short. I also have my CG slightly tail heavy which helps. Also be sure there is no grass stuck in the fan unit. Any grass caught in the fan will definitely degrade power.

[Blackhawk71]

I thought the same thing about the 8S but i‘m considering all possibilities. I want to get this model in the air. I checked the wheels and running freely. I haven‘t done any take off with flaps down yet...it might help?! AoA is big concern due to the behavior of fuselage during take off. I personally think that the esc is fine. What could be another source of a lack of thrust are the intakes maybe they are to small........but then why would I have the problem and others don‘t.......I will try it on Friday and set the cg back......and see what happens.....

[RCjetdude]

8S isn't necessarily a cure for your problem because of the additional weight penalty. I already had the fan so that is what I went with. I find it odd that increasing the timing saw no increase in thrust. Almost seems like something is limiting airflow but I don't believe your cheater or intakes are blocked. I do use 1/2 flaps to take off but have not had any trouble getting off grass myself. The grass I flew it off of was like a fairway. If the wheels are spinning freely and the ESC is calibrated you could try some flaps and see what happens. Make sure you are not nose heavy. You want it to be able to build up enough speed to become airborne without forcing it. Last resorts would be to try a different ESC and motor but that is expensive. Shorter grass might also help if there is even an option for that...just throwing out ideas here. Battery could also be an issue if it is tired or brand spanking new. Bad solder joints?

[Blackhawk71]

How about the weighing after the 8s modification ?
About the question how much it pulls if i set the the esc timing to low it pulls around 98 Amps at medium 115 Amps and with the timing set to high it goes up to 124 Amps. like the of model a lot so i like to fly it. It’s a pity but i have no acces to a paved runway........unfortunately i have to live with the grass strip.....are you guys taking off with flaps?

Sorry if i‘m writing with the time delay. I‘m living in Switzerland so we have at least 6 hours more the you guys!!
But in any thanks for all the ideas and help it’s highly appreciated.....

[bill34207]

You may want to put a watt meter on it and check for battery voltage drop under load. That 1680 motor should be pulling over 120 amps at full throttle.
That's the reason I went to a Jetfan 90 and 8s on mine. Didn't like the short flight times and overheated batteries it gets on 6s