E-flite F-15 Eagle DF Twin ARF - RC Groups

E-flite F-15 Eagle DF Twin ARF

Mike Llewellyn looks at the E-flite F-15 Eagle. This EDF twin ducted fan ARF model is ready to take you on a thrill ride!

Splash

Introduction


Wingspan:36”
Wing Area:~400 sq”
Wing type:Foam - Symmetrical
AUW weight:Advertised – 40-50oz Actual - 42oz 1.19kg
Length:47”
Servos:5-8 Micro
Transmitter:Spektrum DX7
Receiver:Spektrum AR500
Battery:Thunder Power 2100mA 3s LiPoly
Motors:BL 420 FAn Outrunner 3800Kv
ESC:40 AMP ESC v2 E-flite
US distributor:Horizon Hobby
F-25 Eagle ARF:E-flite F-15 Eagle
ARF Price:$159.99

The impressive E-flite line of RC aircraft from Horizon Hobby are simply amazing. The F-15 continues their foray into EDF models - and a twin to boot. It is made from EPS white foam that painted and marked to look just like a full scale Eagle.

The shipment arrived double boxed safe and sound from Horizon Hobby. It comes in a large box which is needed to contain the massive fuselage! In ARF form the assembly is limited, and yours will be in the air quickly.

Kit Contents

Kit includes:

  • Fuselage
  • Wing and tail surfaces
  • Pre cut canopy
  • Battery hatch quick battery access
  • Factory hinged ailerons
  • Retracts
  • Hardware (Push rods, horns, clevis, tires and tail wheel assembly)
  • Decals and markings
  • Picture assembly guide and text instructions

Kit requires:

  • 2 - Outrunner Brushless Motors
  • 2 - 3s ~2100 LiPoly batteries
  • 5-7 Servos (3-Retracts, 2-Ailerons, 2-Stabilator, 1-Nose steering)
  • Receiver
  • 4-5 channel minimum transmitter

Included for this review:

Thunder Power 2100 3s Packs

  • Brushless Outrunner motors
  • E-flite S75 sub micro servos
  • 40 AMP ESCs
  • Dimension Engineering Park BEC

Assembly

The Horizon Hobby F-15 Eagle will require some assembly work to have it complete. This ARF was ready with several hours of assembly work. The foam parts enable you to keep the weight down.

Done by the factory:

  • Ailerons hinged and glued
  • Battery tray
  • Paint and markings

The builder needs to:

  • Install the tail surfaces
  • Glue the wings to the fuselage
  • Install the fans and power system
  • Install radio system
  • Install the retracts if desired

Fuselage

The fuselage is large and I started with that per the instructions. The stabilators were first on the list. The stabilators have factory installed wires that run into cams in the fuselage. These cams were factory installed, and I ran into a challenge as the were not aligned. I simply re-drilled so the stabilators were aligned, and then added fiberglass plates to act as the internal cam.

The control arms were added, but again I ran into a small snag. In order to install them I had to cut small reliefs in the foam fuselage sides.

Power system

The fans were installed at the factory but needed removal so the motors could be installed. The screws used to attach those were very soft, and one stripped and needed to be drilled out. I replaced that hardware with harder screws.

Landing gear

The model includes both retractable landing gear and fixed gear. I chose fixed gear as our club runway is a bit rough for small retracts. This also saved weight and additional servos.

The nose gear was already mounted in the nylon cam unit. It is steerable for better ground handling.

The F-15 Eagle includes retracts and the use of those will require three additional servos. To keep weight and complexity down I did not install them on this model - yet!

Vertical Stabilizers

The vertical stabilizers do not have functioning rudders. I do like rudders on twins but adding two more servos and wiring adds to the complexity and servo count.

Equipment installation

The center of the fuselage becomes busy with wires quickly. With two motors, "Y" connectors, batteries and an RX will use all of the center fuselage space.

Wing

The wings have molded pockets that fit the S75 servos perfectly. This allows for short linkages that go directly from the exposed servos to the aileron control surface horns. Each aileron uses a separate servo.

The wings then glue to the fuselage. I strongly recommend at least 15 minutes; that allowed me the time necessary to align everything properly.

Power system

The E-flite F-15 was powered with the recommended BL 420 3800Kv outrunners made for these fan units.

Amp draws

These high KV outrunner motors is perfect for use with 3s packs. They produced the following results:

Motor statistics (each motor)
Fans Amps Watts Voltage
6 blade 23 239 10.4v

I fly the F-15 Eagle with this base recommended power system, and it provides good sport power. It is not the fastest EDF in the sky but it flies well on the stock system.

Battery

I used two Thunder Power Pro-lite 2100MAh 3s packs. I have used many of the 2100s, and they are excellent packs. They easily handled the 23 AMP draw of each motor.

Finish

The E-flite F-15 was left as raw white foam but does have some paint on the wings and tail feathers. I am really fond of the Edwards AFB paint scheme they replicated. Care is needed when handling the model as the foam will dent easily. While most of the scale details were spot on the nose of this model just looks a bit off to me. Still an attractive plane, however!

Flying

With the 3s battery packs placed in the tray the model was significantly tail heavy. Make sure that you check your CG. I placed one the packs in the nose area near the nose gear to achieve the recommended CG.

I used my trusted Spektrum DX7 transmitter for this plane. Rates were set as recommended in the manual with ailerons at 12mm and 25mm for high rates. Elevator were set at 19mm and 25mm each direction. I found the low rates on elevator to be much too soft for my taste and increased the low rate to about 25mm and about 33mm for high rates. I used 15% expo for all the primary flight controls. I should note while I liked these rates control surface throws are a very personal preference.

I set the flight timer to count down from 6 minutes of mixed flying. In this mode it gives an audible warning to land well before the 3s packs were depleted.

The large E-flite F-15 is very attractive and an impressive model both on the ground and in the air. I knew from my past experiences that it would fly well as all my other E-flite planes did - and I was correct!

Takeoff and Landing

The F-15 with the stock power system required about 100-150 feet of ground roll out on a hard surface to reach flying speed. Rotation takes some elevator input, so do not be afraid to provide a pretty good amount of up to rotate. It was very docile in pitch authority so I increased throws after the first flight.

Landings were also very easy as this model with the large fuselage slows down very well. As is the case with most EDFs you will need to keep some power on, and do not be afraid to flair this model. That nose will raise high and you set it down on the main gear. Landing with the nose gear high in the air bleeding off speed it is a thing of beauty. Wheel landings are possible too, but the nose high with the mains down were just too cool!

Special Flight Characteristics

The F-15 is actually quite simple to fly. It is not overly responsive in pitch, and it has a wide speed range. The model stalls very predictably for a light model with a large fuselage. When pushed to a stall the model slows down considerably and then drops the nose. I noted very little wing tip drop at all - impressive.

Loops require full power and are easy to keep large and round. Rolls are picture perfect with the high rate aileron throws.

Ronnie took these amazing in-flight shots, and as always they are highly impressive!

Recommended power system

The stock power system provides good sport power but do not expect a rocket ship. Horizon has a more powerful power system for those seeking more excitement. Delta E 480 65mm fan system.

Is this plane for a beginner?

Although not terribly difficult to fly EDF models are not where beginners need to start. Twins are simply not a beginner task. But the F-15 was very well mannered and will not cause any grief for the pilot with just a bit of experience.

Flight Video

Downloads

Conclusion

The F-15 Eagle from E-flite continued the tradition of great flying EPS foam models. This, like the others, flies well with no bad habits noted.

Assembly of this highly prefabricated ARF was straightforward but there were a few noted issues. The stabilator cams were mis-aligned as were a number of the pre-drilled holes for the landing gear. Some of the hardware was not of the highest quality.

Once assembled you will have a very attractive model that is well behaved in flight. In fact the F-15 Eagle flies extremely well and I am confident that this E-flite variant is much easier to fly than the full scale counterpart!

For those who want a power up, note the 480 option for 4s power systems that will make this model a stunning performer and real attention getter.

Pluses:

  • Excellent looks
  • Flight performance
  • Lightweight

Minuses:

  • No functional rudders
  • Stabilator cam misalignment
  • Hardware quality could use improvement

The F-15 Eagle will make a jet pilot out of the sport flyer. Check it out the hobby shop or buy direct from Horizon Hobby.

Last edited by Angela H; Jan 08, 2009 at 08:23 PM..
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Jan 15, 2009, 01:26 PM
Registered User
Michael Heer's Avatar
Nice review Mike. Good to know the strengths and the weaknesses of the plane and its parts. Mike Heer
Jan 15, 2009, 01:26 PM
Registered User
Ed Waldrep's Avatar
The stock exhaust size is really too big, you get lots of thrust but the exhaust velocity is low. I suggested this in one of the threads and a modeler necked down the exhaust size using plastic cups, and he gained about 8 mph in forward speed, at the cost of some climb rate and acceleration ability, but hey it's a jet, it wants to go fast! But a higher power setup is probably the best idea.
Jan 15, 2009, 01:48 PM
We shall serve the Lord
kingsflyer's Avatar
Nice review Mike. I really liked Ronnie's pic of the F-15 in front of you and your MiniMe helper complete with his matching headgear - LOL.

Do you think you could fit the E-Flite DeltaV-15 units inside the F-15? Then you should have plenty of power for the extra weight of retracts and sustained vertical performance.

Old Saying - Only substitute for power is MORE POWER.

Mike McD
Latest blog entry: LEDs on my T-28
Jan 15, 2009, 02:45 PM
Slow Flyer
Bombay's Avatar
Great review as always...plenty of info.

Question: I saw another video review of this plane. Everytime I see a vid, the fans make a wah-wah-wah-wah sound (out of balance, pulsating sound) that I usually do not hear on other edf's. It is more noticeable when more throttle is given. It sounds like the fans are not running in unison or they are out of balance. Is this normal?
Jan 15, 2009, 03:16 PM
Registered User
pda4you's Avatar
Thanks guys!

Ed - I should try to constrict those a bit....for some more speed.

Mike McD - Yep the larger fans will fit - or at least Horizon says so!

Bombay - the sync is a tad off - thus the wah-wah thrum sound. You can hear the same on a full scale especially when the engines are on the fuse and you are sitting by them! Makes you nuts after a while!

Balance is pretty good on the fans.

Mike
Jan 15, 2009, 03:16 PM
Dr. Dave
Good stuff Mike. It might be the video sound, but it sounded like the engines never synched. Do they sound like that for real? Almost like the leads to the motors differ and there is some resistance on one motor and not the other. Maybe even some rubbing of the fins? Maybe its normal too.
Jan 15, 2009, 03:23 PM
Registered User
pda4you's Avatar
We posted at the same time Dave!

Yep the fans never sync. When you listen you can especially hear it during throttle changes. Full throttle is most noticeable. Not bad at lower power settings. Motor wire lengths are identical. Battery is a bit longer on one ESC, but I don't think that would do it???

You do have to be careful - the fan blades did rub initially. So I carefully sanded and balance the blades.

A bit of the other factor is the flying site was HUGE - two large vacant parking lots. The resonace in that concrete canyon really seemed to echo the sound too!



Mike
Last edited by pda4you; Jan 15, 2009 at 03:31 PM.
Jan 15, 2009, 06:08 PM
Slow Flyer
Bombay's Avatar
Quote:
The resonace in that concrete canyon really seemed to echo the sound too!
Although, unfortunately, I don't think that explains the sound. I noticed the sound when I saw the video review here. It is the same wah-wah-wah sound.

And if you go to horizon's website, the videos available have a similar sound (a lot of wind too).

EDIT: In reply to the post below, got it. I thought it was important to note that sound was not restricted to your plane alone.
Last edited by Bombay; Jan 15, 2009 at 06:36 PM.
Jan 15, 2009, 06:22 PM
Registered User
pda4you's Avatar
Quote:
Originally Posted by Bombay
Although, unfortunately, I don't think that explains the sound. I noticed the sound when I saw the video review here. It is the same wah-wah-wah sound.

And if you go to horizon's website, the videos available have a similar sound (a lot of wind too).
Please read my entire post - it is out of sync motors.

Mike
Jan 16, 2009, 05:34 AM
Triple boxed goodness!
simon737's Avatar
Great review, i'm surprised at how slow it landed, i guess thats the difference between the foam F15 and the ply/balsa Hawk??

Thanks again.
Jan 16, 2009, 07:22 AM
Registered User

good review


Flies great seems to land nice and slow and looks the part in the air. Needs a Dude, Dude!
Jan 16, 2009, 12:49 PM
The Flying Herb
rstein9's Avatar
good looking plane, but have never seen an edf with any power.

150 feet to take off? I want to take off in 10 feet!

Herb
Jan 16, 2009, 12:52 PM
The Flying Herb
rstein9's Avatar

wing loading


i noticed that they neglected to add this vital piece of information. Anyone know?
Jan 16, 2009, 02:34 PM
Registered User
Quote:
Originally Posted by rstein9
i noticed that they neglected to add this vital piece of information. Anyone know?
400 sq in and 42 oz is info provided--what more do you need? If math challenged, that works out to about 15oz/sq ft....


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