Some time ago, I got into my first twin EDF. There was a certain fascination with a pair of EDFs with their characteristic whine. The only downside was that in order to get any real performance the plane had to carry a significant sized battery due to the fact that a pair of EDFs would draw huge amounts of amps. With the intro of lipo batteries, the physical weight of the battery could be much less, but that still didn't help the fact that a pair of EDFs could still torture a flight battery. As technology in the smaller EDFs has come into play, it sure seems we're in the golden age of electric jets and with that comes another member of the Skyangel Jpower lineup of microjets.




The F-15 was designed in 1967 as an air superiority fighter and since it entered into service, has been sold to several countries and is expected to remain in service past until at least 2025. This new model in the Skyangel line is molded from tough EPO foam and features twin 35mm EDFs with brushless motors. It features a lightweight servo arrangement of only two servos and uses Delta (or Elevon mixing depending on your transmitter) that couples the elevators and ailerons together. This system is very effective on small models that have equally small flight control surfaces. I've had quite a bit of EDF jet experience along with micro airframes so when I saw this model available as an airframe only, I had to make the purchase. F-15s are not quite as overmarketed as some of the other planes, in fact this is the only micro F-15 that I'm aware of unless one wants to convert an old stick and tissue model. That in itself makes the decision easier for those who like flying more than building from scratch. The model is also available as a plug and play for those wanting virtually instant gratification, just add your own receiver and lipo to round out the complete package.





The model arrived from www.hobbyb.com in perfect shape, excellent packing by the vender who is a relatively new company based out of Canada. They appear to be the go to source for the Skyangel / Jpower line of Jets and Warbirds as their selection is much greater than what I've seen elsewhere. Prices looked great and shipping was not out of line, all the better! They even carry spare parts like control horns and rods, EDF fans, clear canopies, motors, etc. for a well rounded offering of products. I had run across several people who successfully ordered from them so I indulged myself and bought several items including the micro A-10 and the new 50mm Screamer.


The parts were laid out and the plan was formulated.







I typically like to mock up the plane first, this model's construction is slightly different. The main fuselage is made just like the other Skyangel jets, including a magnetic EDF cover. The difference here is that the vertical stabs would have to be glued to the fuselage before the horizontal stabs can be glued in place. Since the model's power system and servos need to be installed, it's best to leave off the rear surfaces so that the model can rest on it's back during the majority of it's assembly. Once the powersystem is completely installed, then the final parts are added.




The 2g servos are glued into place and the wires are run in thier pre molded channels to the center of the fuselage. The receiver location was chosen to be in the very rear of the plane for several reasons. The first was to place more weight in the tail in order to balance a heavier lipo if desired. Another reason was to eliminate the need for any servo extensions and to keep the receiver far away from the speed controllers as well as the lipo. 2.4 ghz has been known to have difficulty with being shielded by a lipo so there will be no potential issues here.



　

The EDF units are mocked into place to test fittment and all looks great. This powersystem was removed from the MIG-29, another skyangel jet that had been flown into oblivion and the airframe was getting tired from impacts due to my bravery. EPO can withstand so much more abuse than EPS foam or balsa that you find yourself doing stupid stuff like inverted passes attempting to brush the grass with the vertical stabs, fly in between bushes and other things that one wouldn't do when flying a fragile airframe. The motors and fans are carried over, but I have chosen to upgrade the ESCs to a pair of 10A. The stock escs are rated for 6A and work fine for stock voltages, but I'm not one to normally be satisfied with basic performance levels. After all, the F-15 is supposed to be an air superiority fighter and this one comes with drop tanks and ordinance, I figure it should be assembled with more than just basic power. It will be able to use a 2s lipo if I'm in a lazy flight mood, or rip along on 3s power when called upon.






After the fans were mocked into place, the power system was removed from the airframe and the stock 6A ESCs were seperated, new 10A ESCs that were 3s capable were installed. The during the test, one fan was vibrating and I discovered a hairline fracture on one of the impellers. I swapped both impellers with the three blade versions that are typically supplied as extras when purchasing an ARF. This would be a good test as to how those 3 blade impellers perform. The theory is that the reduced rotating mass would allow for a higher RPM and a reduced amp draw. The result with 3 blade impellers is 14.7 amps for the pair. So at 7.35 amps per fan, that's pretty darned effecient on 3s.


After everything tested fine, the fans and ESCs were installed into the airframe and held in place with a little silicone glue. This prevents any unwanted fan movement and takes the burdon of holding the fans away from the hatch cover. The main power lead was fed up to the large battery area and the hatch cover was popped into place. Everything was tested once again just to be sure, now it's time to finish the model.




The horizontal stabs are glued into place with 5 minute epoxy and allowed to dry. Next, the elevators were glued into place and also allowed to dry. They have to be done in this order as the vertical stabs play a major part in the mounting of the elevators. Once those parts are secure, all that is left is to install the control horns and rods. The control rods are attached to the servos and the horns, secured with a set screw and final testing performed.




The kit doesn't come with a pilot figure like the plug and play models but I had one left over from a Mig 29 so I glued him into place and attached the clear canopy with a flexible silicone type glue. That assembly pops into place with a mounting tab and magnet and we're ready to rock and roll! The CG was verified to be 32mm back from the laeding edge wing root so it was time to take a maiden flight test hop.







Flight test


The hand launch was fairly uneventful with just a hint of roll to the left. After just a couple seconds I immediatly pull the stick back and pointed the nose straight up and it climbed straight up without any drama. The first flight's main purpose was to test for any thrust line issues that were quite apparent in the Mig-29. Even though I thought it was a fun model, it has some issues. This F-15 shows none of those traits and flys rock solid. In fact, it's perhaps among the most stable I've flown. There are no pitch issues when going to full throttle nor chopping the power and going dead stick, It actually behaves like a much larger plane that is devoid of any twitchy handling. Rolling verticals, large and even loops, inverted, and nice dead stick glide properties. In fact, I didn't even do any programming in the transmitter. I was expecting a hair more speed, but perhaps after playing with the new 50mm Screamer on 4s I might be a little spoiled. I cannot really complain as it moves along quite nicely. The 3 blade impellers sounded fairly quiet compared to my Mig-29, the thrust was good and the model cannot be described as underpowered in even the slightest degree. Once I swap in a pair of 5 blade impellers I will post a follow up of the flight performance.

The weather conditions have not been the greatest, there are tropical storms headed our way and the conditions show in the video. The lighting was a little challenging as was following the model, but you'll get the idea of how well behaved this model is.

So here is the maiden test hop

F-15 35mm Maiden test (2 min 40 sec)

In conclusion, the F-15 came out better than expected. There are no ill handling traits, there is plenty of room in the battery compartment for a wide range of lipos, overall I can see this being a favored model for park flying. The dead stick glide is quite predictable, the power is great on 3s, the sound is good, I can't really find much to complain about.

The Pluses

*Durable EPO construction
*Fairly easy to build
*Excellent flight characteristics
*Large battery compartment
*Excellent space for electronic componants

The Minuses

*No instructions included. It's not critical, but even with an airframe only, the CG should be indicated.
*No pilot figure like what comes with the plug and play models.
*Vertical and horizontal stabs require care when being glued to ensure proper location.
That part is not quite the no brainer like some of the other Jpower models. It's still fairly easy though.
*Should probably have more reinforcement to the flight control hinges.

The positives really do outweight the negatives by a wide margin. Consider the negatives a minor gripe.


So if you like the F-15 and can fly larger models, you should have no problems with this one. The flight characteristics really do feel like it's a much larger airplane but you can keep this in the back seat of the car for a lunchtime flight or two in the local park. It's easy to hit your spot on landing, the EPO construction should allow for quite a few tumbles that would turn EPS foam into confetti. is this plane for a beginner? Maybe.... I could see this being a first EDF for someone that has experience on other trainer type aircraft due to the fact that there are no bad handling traits and a dead stick glide with this one is exceptional for a micro. So there should be no worries in selecting this model.

Joe 1320,

Thanks for taking the time to share your project. Your right, you don't see too many F-15s. I don't know if the F-15 has become passe, but I have a Nico Hobbies kit I'm looking to convert. The JP/SK EDF is a likely canidate to power it.

Ksqm

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Thanks Joe! I enjoy reading your reviews.
I have a thing for F-15 and look forward to you getting her in the air.

Will be watching this with interest

I also purchased the F15 from HobbyB and at the same time ordered the basic kit as a spare based on my experience with the 35mm MIG29

Have been running it on 2S (610mAh 20C) but its performance is marginal, and have had a number of run-ins with terra firma. I think it may be OK with some quality Lipo with a higher C rating but I do have a pair of 10amp ESC and may take it to 3S

Seems to be a more stable platform than the MIG29 and definitely gets a lot of comments from people passing by

What colour scheme are you going to use??

The flight review has been completed and the original post has been updated.

Originally Posted by Boofhead

Will be watching this with interest

I also purchased the F15 from HobbyB and at the same time ordered the basic kit as a spare based on my experience with the 35mm MIG29

Have been running it on 2S (610mAh 20C) but its performance is marginal, and have had a number of run-ins with terra firma. I think it may be OK with some quality Lipo with a higher C rating but I do have a pair of 10amp ESC and may take it to 3S

Seems to be a more stable platform than the MIG29 and definitely gets a lot of comments from people passing by

What colour scheme are you going to use??

I'm not sure of the exact color scheme yet. I do agree, this kicks the mig's hiney. It's a much more stable platform in the throttle transitions and in it's handling traits. Step it up to 3s..... check the flight video and that should sell you on the higher voltage.

Originally Posted by Joe 1320

The flight review has been completed and the original post has been updated.



I'm not sure of the exact color scheme yet. I do agree, this kicks the mig's hiney. It's a much more stable platform in the throttle transitions and in it's handling traits. Step it up to 3s..... check the flight video and that should sell you on the higher voltage.

Thanks for the feedback Joe - definitely will retrofit the 10amp ESCs and take it to 3S - looks great

Very nice review.
I would love an F-15, but unsure whether to buy the kit or complete ARF.

Couple questions if you don't mind:

Are you using the motors&fans that came with your MIG-29, or did you upgrade these?
Any suggestions/links for complete 35mm fan units?
Ones I can find online are ~$20-$25 each, but I don't know the quality so if the "stock" ones that come with the ARF can handle 3S and are pretty good, may just go for that.

What size MAH 3S battery are you using? C rating?

thanks!!!

Originally Posted by Kurt

Very nice review.
I would love an F-15, but unsure whether to buy the kit or complete ARF.

Couple questions if you don't mind:

Are you using the motors&fans that came with your MIG-29, or did you upgrade these?
Any suggestions/links for complete 35mm fan units?
Ones I can find online are ~$20-$25 each, but I don't know the quality so if the "stock" ones that come with the ARF can handle 3S and are pretty good, may just go for that.

What size MAH 3S battery are you using? C rating?

thanks!!!

I did in fact use the stock fans and motors that came in the Mig. The fans and motors handle 3s just fine. The "other" fans on the market are likely the AEO fans and those consume lots of power, I wouldn't use them in this. Hobbyb.com carries the correct fans and motors by themselves. The fans and motors aren't cheap, but the reality is that they really aren't that bad. I was used to paying $25 for a decent inrunner and another $8 for a fan in several of my 40mm EDF projects. Heck, my 747 took 4 of those.


I used a 3s 800 mAh 25C lipo, it balances the plane nicely as it sits to the rear of the battery compartment.

Now as far as whether to get an ARF, or plug and play...... if you want to be in the air very quick, then a Plug and play does that. If you want to step up to 3s, you'll have to pull out the escs and swap them. Those 6A stock ESCs won't cut it. No matter what, the airframe is a good one so you'll be happy with either one.

thanks Joe.
So would be $24 kit, 2x$22 motor, 2x$4.49 3-blade fan, and 2x$9 10A Tunigy Plush ESCs will be the way to go. + an Orange RX.
http://www.hobbyb.com/index.php?main...d=35mm&x=0&y=0

ARF version looks pretty cool, but don't mind painting a kit.

cheers!

Originally Posted by Kurt

thanks Joe.
So would be $24 kit, 2x$22 motor, 2x$4.49 3-blade fan, and 2x$9 10A Tunigy Plush ESCs will be the way to go. + an Orange RX.
http://www.hobbyb.com/index.php?main...d=35mm&x=0&y=0

ARF version looks pretty cool, but don't mind painting a kit.

cheers!

Yeah, don't forget about servos..... you need 2. a pair of 282 single screw and the rx415 orange receiver will work fine.

That setup will kick butt. I flew mine pretty hard today, you might want to go with 3s 800 mAh 30C if you like to fly wide open throttle the whole time. The 3s 800 25C got a little warm. No problems, but I tend to like overkill.

Gotcha. Figured I could use a couple of the extra HXT900s I've got, they're not that much bigger than 282s.
Have to check if these 1A Nano-tech 45-90C will fit
http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html

Have a couple of these in 1.3A for my Radjet and really like them.

cheers!

Originally Posted by Kurt

Gotcha. Figured I could use a couple of the extra HXT900s I've got, they're not that much bigger than 282s.
Have to check if these 1A Nano-tech 45-90C will fit
http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html

Have a couple of these in 1.3A for my Radjet and really like them.

cheers!

Those hxt 9g are easily three times the size of the 282A. 2g vs 9g. that's and extra half oz of weight for the pair. You might get by with the 5g servos, but you'll still be removing foam to fit them in place. Just keep in mind that micros are much more sensative to weight than larger models.

Got the F-15 now upgraded to 3S - added a pair of the Plush 10amp ESC but managed to break one of the wires going into the EDF motor. Did have a spare motor from my last Hobbyb order which went in after lots of swearing

Also straighted up the inlet which had taken a hit last time the ground ran into it

Will replace the very bent control rods to the elevators with perhaps 1mm carbon fibre rods

Hopefully maiden on 3S tomorrow morning - all going well I may rip out the 3S setup in the MIG-29 and add it to the spare F-15 airframe I got when I purchased the kit

Originally Posted by Boofhead

managed to break one of the wires going into the EDF motor. Did have a spare motor from my last Hobbyb order which went in after lots of swearing

Bummer. At least you had an extra and you'll be happy when you give this a go on 3s. That reminds me, I need to order more fans and motors for the next couple of projects.

I was thinking about those control rods. The short ones aren't bad, the long ones seem a little soft. I'm thinking that some carbon fiber tube would slide right over those and the increase in rigidity would be huge.

Had 3 flights on 3S this morning - definitely a much nicer experience and more stable and predictable than the MIG-29 on the same setup

This is running the 5 blade fans and using a 500mAh 25C lipo, with about 10grams in the nose to get the 32mm CoG

Batteries were quite hot after the flights - Joe what are your thoughts on putting in the 3 blade fans to get the amps down a bit?

Also got a big thumbs up from a few of the people out walking this morning - does look good