Official Freewing JAS 39 Gripen 80mm EDF Jet

[janmb]

That doesn't look at all like high alpha. That looks like it's about to land.

Yes it is a landing mode - ironically to land with less alpha than you otherwise could.

[Marktur]

First of all, this is very well flown by Justin. I will definitely give you that.

An optimal setup would first of all be a far more neutral CG, slight DOWN pitch on canards, and slight up pitch on elevons. With correct CG, that setup will high alpha hands off. And without preventing the canards from doing their main job.

Yes - Excellent flying!!!

I made some modifications for flights 4&5: 2mm "down" on the canards, added more throw all around - max high rates, lowered the Expo to 30% to get rid of that "mushy" feeling. My CG is pushed back to the recommended area (as it was for maiden).

My thoughts:
This is one of the easiest jets to fly from Freewing...maybe the Avanti is easier, but for a military jet, it sure flies like a pattern ship! Locked in, on rails, and I think the little bit of down trim on the canards removed the tail-wag.

I also fly in the afternoon, and we normally have E to W winds here (right down the runway)....it sometimes gets funky on my eyes in that "3rd" turn to line up with the runway. I was trying to see the paint for orientation, but with a bright sun behind it, you come to realize that it looks like an "arrow" and is very easy to see what it is doing and of course the direction it is flying. (so zoom back mentally if you get disoriented - let it fly without trying to do radical corrections - ie. push down the nerves - and a little rocking of the wings tells you everything!)

I love the vertical of the stock system...of course I would trade off vertical for a little more speed for low passes...but hey, don't fly right after a turbine, and you won't feel the need to go faster! (But wouldn't this be awesome with the tiny jet turbine in there???? Buying lotto tickets this weekend!)

All I can say is that in 5 short flights, this is one of my all-time favorite jets! If you're thinking about one, get it, you will not be sorry!

Thanks to all for the tips, pointers, printed tail cone, etc. You guys are great! :)

[Evan D]

Mark, I looked but don't see that you posted your CG measurement.

"My CG is pushed back to the recommended area (as it was for maiden)."

[Jlink125]

4th flight LIVE High Alpha/Slow flight demo.

This is my 4th flight on the model that I did LIVE on FB demonstrating the slow flight/High Alpha capabilities of the model at the stock CG location.
I also demonstrate the “flap” function I have set up on my canards using only 6 channels.

With almost 4000 views on FB already, I took the time to upload it to YouTube to be able to share it. UNFORTUNATELY this means there is a pretty low quality/frame rate off the live feed recording.

This is rocking the 4400mah 70C Roaring Top from RCJetWerx that allow for balancing on the factory CG marks on the jet, while also giving great power into the vertical out of High Alpha passes.

https://rcjetwerx.com/product/rt-6s-4400-70c/

Very impressive! That is WITHOUT DOUBT the Definitive high alpha demonstration on the Gripen model. The way you can hold an even height and steady show line in full control. I have not seen a better "low and slow" demo to date. Its very interesting that you did it at the factory CG location. From everything I have seen so far I'd say you clearly nailed the control set up for that type of flying“

[Lcacing]

I had some time in the shop this weekend and began the planned modifications. Landing lights were added to the main gear (as the full size has) by bonding aluminum tubing to the struts with KB weld into which the LED's slide. Plastic tubing was used to hide the springs.
The silly nose light was removed and a bulb fitted to a door made from 'glass sheet to sort of replicate the real Gripen. After some trial and error I used pinned hinges and a spring from the Venom nose door to close it and then cut back the existing doors.
The struts and insides of the doors were painted white and the wheels got a bit of detailing, as did the exhaust nozzle with some weathering and a flat coat applied. The inside was covered with aluminum tape to enhance the LED 'afterburner" and the last inch or so painted to simulate a jet pipe. The 'burner is one of Gooniac's (thanks Ray!) and although not installed for the first 2 flights it's in there and working now and I think it's going to look great in flight.
Tom

I really like the gear door mod!!! My Gripen still in the box, have to wait until Christmas to open, but I think the F4’s nose gear door assembly will work. I know is not scale but one can even go with two landing lights. It is the correct width just need to cut it, plus it already has hooks for the springs.

[Pogo]

There you go- sweet!
Tom

[TangoVector]

Well being as the MODEL flies VERY well with my setup as shown in my video.
Being also as the REAL aircraft ALSO lands this way with canards deflected up, I HIGHLY recommend people try my setup with the MODEL.

I think your version of using the canards in landing configuration is great, like having the landing attitude on a switch. If that works well with a large CG-range and is scale behaviour, then what could be better?

My own plan is to use more channels to try and combine down elevons with up canard and get it even closer to scale behaviour and looks, not because it's necessary, but because it's fun to try and see if it works, since it is a hobby.



The full size Gripen canards do a lot of things, they alter the airflow over the wing and they also work together with the elevons in pitch at subsonic speed. Could it be that the reason the canards are mostly pointing downwards on the full size machine is not only to help with airflow, but also to keep the aircraft from pitching up due to its unstable tail heavy configuration? Since it is a good design it is probably doing both.

[janmb]

Could it be that the reason the canards are mostly pointing downwards on the full size machine is not only to help with airflow, but also to keep the aircraft from pitching up due to its unstable tail heavy configuration?

Well, most of the time, despite being somewhat negative relative to the aircraft, they are not net negative relative to the oncoming airflow. Neutral or a tiny bit positive most of the time. Stabilization also makes that a bit harder to read, since they move a LOT as part of that when flying slow.

[Airguardian]

[URL=filedata/fetch?id=289331&d=1607378897]Being also as the REAL aircraft ALSO lands this way with canards deflected up, I HIGHLY recommend people try my setup with the MODEL.

They do that for landing, not for high alpha.
You seem intent on keeping to miss the point.

[JLambCWU]

They do that for landing, not for high alpha.
You seem intent on keeping to miss the point.

Never said I used them for anything other than take off/landing. You’re clearly missing the point.

...and didn’t listen to the video

[Airguardian]

Well, you are claiming to have made the 'ultimate high alpha demo' which uses a CG setup that is not optimal as the canards need to be pitched up for the jet to hold there.

Mine still has that problem too as I couldn't shift CG far aft enough (now that I have a Jetfan, that is going to change).

Since you mixed the 'canard pitch-up trim' with the high alpha demo video, I think it is worth addressing so as not to cause confusion. ;)

[TangoVector]

Does anyone else think it will look good with the under wing hard points attached? If so, any 3D-prints available? If not, I think I will make some and share, but it will take quite some time. It might also take away some of the wing-rocking tendencies (just a wild guess and hope).

[JLambCWU]

Does anyone else think it will look good with the under wing hard points attached? If so, any 3D-prints available? If not, I think I will make some and share, but it will take quite some time. It might also take away some of the wing-rocking tendencies (just a wild guess and hope).

Jeremy Solt has, posted a ways back with his.

[Evan D]

Fyi- the TVs for the MiG are available on the RC-Castle web site but not the Gripen... Yet

[Airguardian]

Having way too much fun with smoke!

[Pogo]

As the ring in front of the exhaust nozzle was omitted by Freewing I made one from a Red Solo Cup (there may be a song). Lines were scribed in the plastic and I sprayed it with a metallic finish although most photos show it the fuselage colour. The circumference was a little small so an additional piece was needed in the bottom. The silver blocks in the photo are the 34 grams of lead I added for the first flights.
Tom

[HaroldAnderson]

As the ring in front of the exhaust nozzle was omitted by Freewing I made one from a Red Solo Cup (there may be a song). Lines were scribed in the plastic and I sprayed it with a metallic finish although most photos show it the fuselage colour. The circumference was a little small so an additional piece was needed in the bottom. The silver blocks in the photo are the 34 grams of lead I added for the first flights.
Tom

That looks good. It's amazing what you can do with common materials. My AL-37 is flying around with two margarine containers as fake nozzle extensions. :-)

[HaroldAnderson]

Full flight at high alpha. Well, pretty much.. This flight was with the gyro switched off because of the light wind this evening. I wanted to see how it did without stabilization. CG at 13 mm behind the factory CG. Gens Ace 5000 45C. This was flight number 42 on the Gripen. My other planes are feeling neglected...

[janmb]

Full flight at high alpha. Well, pretty much.. This flight was with the gyro switched off because of the light wind this evening. I wanted to see how it did without stabilization. CG at 13 mm behind the factory CG. Gens Ace 5000 45C. This was flight number 42 on the Gripen. My other planes are feeling neglected...

Great job

[Airguardian]

Great job indeed!
Why the landing gear down though?