Official Freewing JAS 39 Gripen 80mm EDF Jet

[Gary S.]

That 90mm conversion looks cool be interesting to hear how it performs.
I agree with Airguardian ducting / airflow seem to be one of the challenges with this truly awesome model. Yes it has quirks but honestly I have modded every jet I own for one reason or another. I with a few tweaks have it running with an enjoyable performance envelope. Cheers to all out there that are JAS39 Gripen pilots. It is a great jet!

[Evan D]

Very cool!

[TangoVector]

Progress report on my FMS 90mm conversion.

I'm going for a taper to approx 98% of Fan Swept Area at the rear for good static thrust, top speed isn't a priority. I have printed rings to give the tube correct size and shape. The tube in two parts is made of thick paper and will be lined with aircraft-grade extremely thin alu-tape for strength and some type of afterburner simulation, probably kallend s DIY version. Taper goes from 92mm to 81mm at the end, so a F-16 tail cone is on the way (yes I know, but it is close enough for me at this stage).I have opened up the cheater hole and will also add the F-16 side inlets on top as Mtpisgah99 suggested.

A lot of foam has been removed and the tail carbon-rods are too narrow, but I will put in other reinforcements. I'm trying to get airflow as smooth as possible on both sides of the fan so I'm planning to print a more aerodynamic cover for the carbon spar in front of the fan.

This is fun!

[Airguardian]

I think the struggle of this jet accelerating has more to do with the duct design than weight and wingloading (but they add up too).

[Gary S.]

I see now! :D
Nice!
Did you measure how much did the thrust increase?

Airguardian, I did not measure the increase. I am running a Jetfan 1738, moved back to contact the ad on thrust nozzle. I went with the lower kv unit to hopefully keep flight time up, 8s 5000 with little carveout in the back of the battery bay. No counterweight needed, couple mm down on canards. Looks like 110mph (best guess) on a even run. It is still a little sluggish on throttle response compared to some of my other jets, but climbs well. I can only attribute that to the weight and wing loading. I have a guy that I fly with, that flies a mostly stock version and the difference is dramatic. Like bla... vs awesome.

[Airguardian]

I see now! :D
Nice!
Did you measure how much did the thrust increase?

[Gary S.]

[Airguardian]

Can't see the picture. :(

[Gary S.]

These birds definitely need more air. Moving the edf rearward allowed room for additional intake air..

[Evan D]

Maybe yours is but mine is pretty nice!

Wow, is that VT nozzle ever ugly!

[kallend]

Wow, is that VT nozzle ever ugly!

[Airguardian]

Evan, could you go in more detail on how did you prepare the TV nozzle to glue the plastic cover on top?
I plan on following your steps for that. :)

would enabling the TV units for take off be advantageous or will I be asking for trouble.

Will be an advantage.

[Evan D]

Interestingly I made and posted a couple videos earlier...

FreeWing 80mm Gripen EDF overview - YouTube
FreeWing 80mm Gripen EDF setup - YouTube

I fly with a DX-18 if actual number from that would help.

[Steve Balaam]

Hi Evan
Thanks for your advice, could I ask what your control movement settings are?
Steve B

[Evan D]

I did the first few flights with them off for take off and landing. After trying it on full time once I have left it on full time. I have about 40 flights with the TVs now and absolutely love it.

[Steve Balaam]

Received my TV unit yesterday, took four days to arrive in Northern Ireland which is pretty impressive.
I fly off a grass field which has proven challenging to get an EDF airborne, could I ask forum members, would enabling the TV units for take off be advantageous or will I be asking for trouble. Anybody tried this yet?

[rms]

Do any know if I can use this Tomcat programmer on the Freewing ESC?
Did try to ask here but no replies.

https://www.hobbysquawk.com/forum/electronics-and-rc-accessories/rc-electronic-speed-controls-escs-and-becs/297359-esc-programing-card-freewing-vs-tomcatskylord

[Pogo]

since you already curbed the speed air brake piece from the jet , i wonder if you can duplicate it from making a plastic material using 3d machine. if you can i'll buy a pair from you.

Sorry, haven't the CAD skills or interest in printing the panels. As the panel shapes need to be cut out anyway I would think it easier to just use the foam.
Tom

[TangoVector]

You might want to add this inlets. I use 90mm f16. You need to heat it and reverse curb it. Unless different location.

Thanks for the tip! I'm planning to enlarge the bottom one as much as possible for better high alpha thrust, but I think there cannot be too much air since I'm not interested in top speed, so I'll probably add the ones on top also.

[Mtpisgah99]

I'm installing the 90mm FMS 8S, so I need a larger diameter thrust-tube and I think the 80mm version TV-unit will be too restrictive, but there will be some sort of TV later on. A lot of carving going on right now and a redesign of the cheater inlet is in the printer (not really a redesign, just printing another inlet from thingieverse to have something to start with as a baseline).

You might want to add this inlets. I use 90mm f16. You need to heat it and reverse curb it. Unless different location.