LX Model F4 Phantom twin 70mm to 90 mm conversion.

[ddsjoseph]

Some more photos

[ddsjoseph]

a second short Youtube Video

[ddsjoseph]

Today was the maiden flight for the F4 Phantom 90mm EDF. The plane turned out amazing. There was plenty of power and it took off without any problems. We had several cameras including a quadcopter chasing the Phantom. The final video will be edited soon which will include a timeline of photos documenting the build from start to finish. The Video portion of was produced and edited by fellow pilots Justin Dornbush and Jason Shumway, who are professional editors for the entertainment industry. The final YouTube video will be posted soon, but for now I will include a couple of YouTube Links just to give you an idea of what took place during the maiden flight. We checked all the systems and adjusted all the surfaces, programmed the gyro etc before the flight. The only thing we forgot to to was to set the timer. I know its a rookie mistake, but in the excitement of things the timer was neglected. The plane flew for 3min 38sec and ran out of power, seconds before landing. The plane was lightly damaged and the front landing gear got torn off. Here are the links on YouTube.
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https://www.youtube.com/watch?v=mXx3hf41tjY&feature=youtu.be

https://www.youtube.com/watch?v=58Dz_wj-FZU

[bradl4648]

Very nice I like both the mig and the f4 great job! Good luck on the maiden and attach the video please!

[Alpha]

Me too! I eagerly await your maiden report. You've executed a smart, clean conversion to single 90mm. And it looks great next to your MiG-21!

[Aros]

Nice! Looking forward to the maiden report.

[ddsjoseph]

The F4 project build portion is done! I have done the pre flight testing, and here are the results. The horizontal thrust is 5.67Lbs and the Flying weight is 7.69Lbs. The CG is 160mm from the leading edge of the wing, instead of 194mm suggested by the manufacturer. To make the plane balanced at CG point, the battery must be moved forward. The battery placement ends up 3.5 inches aft of the opening of the canopy. Unfortunately, you have to carve some of the foam to accommodate the ^6S 5000mah Admiral battery

[gooniac33]

My buddy has this plane and upgraded the power system to an XRP 14 blade set up with 2200kv inrunners. Heavy but worked very well. But now that the new FMS 12 blades are out he tried those. now instead of 2 batteries it is one 6s 5000 and it works wonderfully! I am curious to see how the 90mm works out... Best of luck with it!!

[Robert Belluomini]

Look forward to your end result. I have the LX F4 with Schuebeler DS30's running on 5S and it has plenty of power. I ran separate channels for both elevators so I can set the end points and throw to match. I did glue the flaps shut and the model flies much better this way and still lands slowly. A FW F4 with twin 80's would be very sweet!

[seaviper]

subscribed!

[ddsjoseph]

I had the same LX Models F4 last year and it proved to be too tail heavy. The Factory suggested CG is at 194mm from the leading edge of the wing, but the true CG is at 170mm. By moving the motor forward it will hopefully solve the tail heavy problem. In addition, the single 90mm inrunner weighs less than the twin 70mm.

[ddsjoseph]

Just wanted to update my F4 build with recent photos. Should be ready to Maiden in a week or so.

[ddsjoseph]

I'm glad to see that there are others who share my enthusiasm for this project.
Thank you for the support. It's a good feeling to share this with people who understand and appreciate this hobby.

[Ks.jetflyer]

Will be watching to see how this works out.

[Kloverzero]

This is awesome! When and if someone makes a good one I will definitely buy it. Anticipating any CG issues with this set up? There were two EDF's mounted farther aft of where the single 90 is going to be located.

I guess we will find out sooner or later!! But I think it will be okay.

[bradl4648]

Great winter project to do who does not like that jet !! Maybe if we tease Alpha hard enough he will do a 90 mm F-4 just now is to weight.

[Bogietrim]

This is awesome! When and if someone makes a good one I will definitely buy it. Anticipating any CG issues with this set up? There were two EDF's mounted farther aft of where the single 90 is going to be located.

[Kloverzero]

How ironic....I am doing the exact same thing!!!! I have had my airframe for a little over two years. I was not happy with the performance even with two Freewing inrunner 70mm fans. I am mounting the 8S 90mm inrunner in it, and if it works well, I will order a new kit from banana and do it with pretty foam. Freewing really needs to get us a Phantom II!!

[Amelkonyan]

Way to go ddsjoseph, in an awsome project.

[ddsjoseph]

I also added a Cheater hole, where the ESC access panel used to be. Also, in the original message I mentioned that I was going to use a single servo for Ailerons. I meant to say Elevators.
Thx