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Apr 03, 2016, 10:42 PM
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Hobby King Diablo 90mm EDF - Awesome Jet!


I absolutely love jets. I enjoy flying all types of planes, from pattern aerobatic to pylon to glider, but jets are my absolute favorite. They're inefficient, heavy and tricky to fly... and I still love them. I've been trying to get a reliable "full house" jet (complete with retractable landing gear) for years, achieved last year when I picked-up the awesome Freewing Stinger 90. However, a composite jet is the dream, and was realized on the weekend when I maidened my Hobby King Diablo.

The maiden was delayed by a month due to the Change Sun fan exploding - in its defense I overloaded it. The damage to the fuselage was enough to warrant some repairs which have come out pretty well - just need to do some touch-up painting now. It had to fly first to prove the repairs were warranted.

I have a Ramtec EDF in a different jet which is all nylon and it happily churns at ~7kW input, but I just don't trust the Chinese plastic fans anymore after the CS fan's demise. Therefore I replaced it with an all-alloy fan system:
- Alloy DPS Series 90mm 12-Blade EDF Unit with Heatsink
- Dr. Mad Thrust 90mm Cast Aluminum Alloy Rotor
No issues with this beast! It's happily turning on 8S Turnigy 5000mAh 3S 40C Lipo Packs (3S + 3S + 2S) using a Turnigy SK 1500Kv motor at ~125A / ~3600W. The AeroStar Advance 150A ESC Opto handled all that current and power without an issue.

I fly from an unprepared field with grass control being conducted by the resident sheep. The landing gear system was as follows:
- Retract units: Turnigy Full Metal Servoless Tricycle Retract Set (90 degree) 1.20 class
- Main struts: Alloy Oleo Strut Suits Mains for 90mm/1.20 Class Jet 2pc cut down and modified to fit.
- Nose strut: Alloy Oleo Nose Strut with Wheel and Rubber Tire (111mm Length, 4mm Mounting Pin)
This all coped beautifully with the slightly bumpy ground.

The jet took about 300ft to rotate and climb-out, with the CG at 165mm back from the LE at the root (rearmost recommended limit). I feel this CG is still conservative as the jet doesn't fully stall on landing (although more elevator throw could overcome that). 300ft is about the same as my Stinger 90 from the semi-rough surface.

I must say this is the nicest non-EPO jet I've ever flown. It was relatively easy to fly, and plenty quick on this set-up. Not the fastest jet I've ever seen, but noticeably faster than my stock Stinger 90. It was also sweet to fly! Aerobatics were easy and I felt comfortable almost immediately with it. I was doing 4-point rolls on the maiden flight!

I landed after 4 minutes of total flight time (2 minutes of "proportional time" on the Taranis timer - the timer counts down proportional to the throttle stick) and recharging the cells revealed ~3700mAh consumed - perfect. The landing was a non-event. The jet slid down the glideslope beautifully and a gentle flare had it rolling out. It does come in a bit hot as evidenced by over 300ft of roll-out. I used 45 flaps and was glad I had them. I also noticed it needs down-trim with flaps deployed, as was suggested by another flyer on the HK Diablo thread. I dialed in 10% down-elevator mix for the second flight and it was all sweet.

This is an excellent jet. The only difficult part of the build was the inlet ducting install, and that went OK. I reinforced the inlet ducts with carbon tows secured using thin CA, and have had no troubles with the inlets. The jet flies precisely and with plenty of authority. It's so much less touchy than my CMP Hawk (Hobby King "black" Hawk) and the landing is a breeze (just a bit hot). The landing gear held up to the job beautifully, but I did strengthen the mounts and wing skins with a few layers of medium glass + epoxy - don't skip this step!

I flew the jet 8 times on the weekend and I loved it. It's better than my Stinger 90 and that's saying something! Now to fix that paint job...
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Apr 04, 2016, 05:57 PM
Vertical Unlimited
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Hobby King Diablo EDF jet (0 min 6 sec)
Apr 07, 2016, 11:43 PM
High Voltage
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I agree 100% . I have flown all types of edf jets and by far its one of most stable composite edf's in my opinion. Maiden on a 9s mototurbine all metal fan unit. Had to relocate battery location to correct the cg. Open fan and no ducting .Awesome jet! Here is a video;


90mm diablo maiden (1 min 49 sec)
Apr 08, 2016, 11:58 AM
Vertical Unlimited
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I'm glad you also see the virtues of the Diablo. Great flight! How was your landing?
Apr 08, 2016, 05:52 PM
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Quote:
Originally Posted by Straight Up View Post
I'm glad you also see the virtues of the Diablo. Great flight! How was your landing?
My friend did the video from his cell and ran out of memory while I was flying. The landing was just as good as the flight. Doesn't need much flaps to slow it down and the stall speed is very good..
Apr 27, 2016, 07:01 AM
Registered User
Thanks for thread. Mine has been sitting waiting to be built. I also selected an 8s set up so it was great to hear about your jet. Take care
Apr 27, 2016, 09:03 PM
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It's an excellent jet. Miles better than my Freewing Stinger 90, which is itself an awesome jet. I like the Diablo so much that I bought another "just in case". Just make sure you strengthen the undercarriage mounts. I used glass cloth and epoxy on the mounts and the wing skin.
Jul 13, 2016, 08:15 PM
Registered User
RCReviewer's Avatar
I just got mine in, but I need to get retracts, oleos and wheels for it, I will be going with a 10S setup.
Jul 13, 2016, 11:36 PM
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Sounds great, RCReviewer! 10S with what Kv motor, and which fan? Are you going for an even higher powered set-up than mine or a "lower current, similar power" set-up?


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