Official Freewing JAS 39 Gripen 80mm EDF Jet

[noradtux]

If higher timing gives more thrust with no downside, why would they ship it with medium timing?

AFAIK inrunner motors require lower timings than outrunners. Motors have one specific timing at which they run "best". But without a proper data sheet of the motor the best timing is hard to know. Also my experience with older planes from China with preinstalled power train is that they don't bother with tuning the ESC, but use its factory default. As long as it somewhat works it seems to be good enough for Chinese manufacturers.

[Mizer67]

Every inrunner manual I've seen so far recommends between 0-12 degrees or less on the high end, of timing.

I'm guessing "high" timing is creating a lot of extra heat in wasted energy for minimal gains, but there likely gains to be had at the expense of longevity and flight time.

[RudyD54]

I met up with Hugh Wiedman who took video of my Gripen’s maiden this past Sunday. Being my first delta and first jet with canards I had no idea what to expect. I found orientation to be quite the challenge at first and needed a change of pants by the end of the first flight. 😆 Orientation improved as I got used to it, but something about the long slender shape and short vertical stab makes it tougher to see than any of my other planes. I set my throws to 100% all around with about 40% expo and I found it to be too numb around center than boom all of a sudden way too much roll for me. Between that and the orientation I ended up upside down and too far away and almost lost it at one point but I got lucky and made the correct guess as to which way I was facing and I was able to recover. After bringing her in I lowered the expo to 30% and dropped the aileron throws to 80%. This felt much better on the subsequent flights. I got roughly 3:30 minutes of throttle time with the SMC 4000s, but I still had some juice left when I came down so I think I can probably get another 15-30 seconds once I get comfortable with her slow flight characteristics as I spent most of the two flights ripping around. I didn’t personally feel like she lacked speed or power flying like that, but I’ll report back once I get some high alpha time in. The packs I’m using are pretty light and powerful so that may be the key by keeping the all up weight as low as possible. It was a little windy so I did notice a bit of wing rock which was unsettling at first but I’m sure I can tune some of that out once I dial in the gyro gains. All in all it was a very successful day and the Gripen flies differently enough from my other jets that I think she’s a keeper.

First two flights:

https://youtu.be/Ef4V5wHpOO0

[Evan D]

Awesome report, congratulations!

[Marktur]

Marktur This was my second flight, but first with the FMS EDF with the 3280 2100kv motor, so I had a good back to back comparison between stock and this setup.

LOL, someone was selling the motor on RCGroups, so I bought that too. Probably should have spent a few more bucks to get it all new, but I'm sure I'll balance the fan well using Gooniac's proven methods.

I'm going to play with the timing before I switch over...not in any rush, I'll probably fly it with the stock components for a bit until I'm flying confident and aggressive, so I can really feel any differences. For now, it is "shiny and new" and not broken...so I won't "fix it" just yet....just play with timing first.

After just a few flights, I really love the jet, and can't wait until Thursday to fly again!

LOL - WINTER CAME TO SOUTH FLORIDA TODAY!!!! Woke up, 54 degrees in Wellington, FL, with no clouds and sunny skies! YES!!! Got 2 meetings this AM, then the wife and I will go let lost on the motorcycle this afternoon! Woo!

[Airguardian]

AFAIK inrunner motors require lower timings than outrunners. Motors have one specific timing at which they run "best".

Would you please elaborate on what you exactly mean by 'best'?

This can be very subjective depending on what you try to achieve.
I guess you mean there is a timing setting where you will get more motor torque for the used amps and heat produced.
I'd call that 'optimal in terms of efficiency' rather than 'best'. For me, 'best' would rather be the setup that gives you maximum thrust as long as the system can deal with it fine without amps skyrocketing to a point where the jet will only fly for 2 minutes. Not the case here! ;)

I'm guessing "high" timing is creating a lot of extra heat in wasted energy for minimal gains, but there likely gains to be had at the expense of longevity and flight time.

It certainly draws more energy but the gains are not minimal in my experience.

I was flying with a bit of a crosswind, and with neutral canards.

For what it's worth, I flew with crosswind myself today and I had a lot of wing rocking too, again. Even with gyros active.
As you can see from my previous videos the jet is perfectly stable in calm weather, so it's mostly a matter of not being very tolerant to turbulence. Flew the Hornet in the same flight conditions and it fared much better for comparison. ;)

[kallend]

For what it's worth, I flew with crosswind myself today and I had a lot of wing rocking too, again. Even with gyros active.
As you can see from my previous videos the jet is perfectly stable in calm weather, so it's mostly a matter of not being very tolerant to turbulence. Flew the Hornet in the same flight conditions and it fared much better for comparison. ;)

I also found mine very susceptible to a gusty crosswind. My ArrowsRC MiG29 handled the same day much better.

[kallend]

I met up with [USER="6116"] I didn’t personally feel like she lacked speed or power flying like that, but I’ll report back once I get some high alpha time in.

Right now mine is stock (apart from some 100g of tailweight for CG reasons). It is plenty fast, although not as fast as my Mirage or Avanti S. What it seems to lack is enough punch to exit quickly and cleanly from high alpha. Perhaps I'm spoiled by the Sukhoi 35.

My 80mm FMS PRO is supposed to be delivered today.

[xviper]

In positive news, I flew my Gripen for the first time with the FMS edf unit. With the battery (5000mAh) at the very rear of the compartment it flew pretty damn great.
The roll axis feels a little unstable with a tendency to rock, but it seems like that's a feature of deltas.
I decided to fly it more scale, and disabled the canards as default, but could turn them on with a switch of course. The plane flew perfectly fine without the canards, much better than I expected. Pitch and roll were plenty quick, but of course there was a ton more authority with the canards on. In general I liked flying without the canards enabled.
Tracks straight and true, CG is about a fingers width behind the molded mark. Flight times are just 3:00 with a 5000mah, but that's with a still-not-comfortable-with-the-stall-speed high average throttle application.

Maybe I missed it but did you post any comparison of thrust performance between the stock EDF and FMS unit?

[Marktur]

Well, that's why you are not supposed to cut those wires and use the pre-tinned part of the motor wires. It's almost impossible to solder that stuff.

There's got to be a way to remove the coating...I've read many "warnings" in the drone groups about cutting motor wires - DON'T DO IT - LOL, I'm sure you love hearing that....but there has got to be a way to get past this. Sounds like a job for Google?

How do you remove resin from copper wire?
A process of removing a polyvinyl formal resin coating from copper wire, comprising immersing the coated wire in a concentrated aqueous solution of formic acid for a few minutes to cause the resin to swell and break the bond between the resin and the wire.

10 Common ways of removing the insulation on enameled wire include:

• Scraping the enamel carefully off with a sharp knife or blade, while trying not to nick the underlying metal wire
• Melting the enamel off with a hot soldering iron in a quick motion so as not to cause a blob of carbonized enamel to stick to the wire
• Sanding the enamel off with either fine sandpaper, or a polishing / sanding head on a Dremel-type rotary drill
• Using a lit matchstick or a cigarette lighter to melt off the enamel, if the wire is thick enough to not get damaged in the process. Really thin "magnet wires" tend to clump up with such treatment
• Not removing the enamel at all, just connecting through it to the metal wire, using either solder + flux + soldering iron, or a "vampire crimp" or "Insulation Displacement Connector" (IDC) type approach.

Hope that helps...

[xviper]

Well, that's why you are not supposed to cut those wires and use the pre-tinned part of the motor wires. It's almost impossible to solder that stuff.

They weren't "pre-tinned". If I'm not mistaken, he cut the bullets off in an attempt to extend the length by soldering on a lengths of wire. My FMS unit came with bullets already on. For me, the length of the motor wires were just the right length. It was the ESC to battery length that was too short and even those, I left the bullets on and made extensions with mated new bullets and a new EC5 plug at the battery end.

[Evan D]

I've cut motor wires before I knew "don't do it"... I scraped the individual strands with an Xacto to remove the enamel. Took a while and had to be meticulous to not cut the wires. I would think careful sanding would work too. If it was me I'd think about just buying a new motor too, I've gotten a bit lazier in my old age.

[James]

I met up with Hugh Wiedman who took video of my Gripen’s maiden this past Sunday. Being my first delta and first jet with canards I had no idea what to expect. I found orientation to be quite the challenge at first and needed a change of pants by the end of the first flight. 😆 Orientation improved as I got used to it, but something about the long slender shape and short vertical stab makes it tougher to see than any of my other planes. I set my throws to 100% all around with about 40% expo and I found it to be too numb around center than boom all of a sudden way too much roll for me. Between that and the orientation I ended up upside down and too far away and almost lost it at one point but I got lucky and made the correct guess as to which way I was facing and I was able to recover. After bringing her in I lowered the expo to 30% and dropped the aileron throws to 80%. This felt much better on the subsequent flights. I got roughly 3:30 minutes of throttle time with the SMC 4000s, but I still had some juice left when I came down so I think I can probably get another 15-30 seconds once I get comfortable with her slow flight characteristics as I spent most of the two flights ripping around. I didn’t personally feel like she lacked speed or power flying like that, but I’ll report back once I get some high alpha time in. The packs I’m using are pretty light and powerful so that may be the key by keeping the all up weight as low as possible. It was a little windy so I did notice a bit of wing rock which was unsettling at first but I’m sure I can tune some of that out once I dial in the gyro gains. All in all it was a very successful day and the Gripen flies differently enough from my other jets that I think she’s a keeper.

First two flights:

https://youtu.be/Ef4V5wHpOO0

Wow! That is a ton of throw on a Delta. I fly it with about 50-60% on the roll surfaces now and she's still more than nimble. Regarding orientation, if the sun is in the wrong place, all models look silhouetted but I actually find the white of the canards easier to see.

[RudyD54]

Wow! That is a ton of throw on a Delta. I fly it with about 50-60% on the roll surfaces now and she's still more than nimble. Regarding orientation, if the sun is in the wrong place, all models look silhouetted but I actually find the white of the canards easier to see.

I realized that once I was in the air and was upside down faster than my brain could process what my eyes were seeing 😆 . I think I'll eventually find an expo/100% travel combo that will feel comfortable with itty bitty stick movements but for now I'm happy with 80% travel 30% expo. I did notice that using the elevon mix built into the IX20, my elevator and aileron throws are automatically cut back to 75% of the total possible mechanical movement which confused the heck out of me at first. I was getting binding and going way beyond the throws called for in the manual when combining full elevator and full aileron so I limited the total servo travel using the absolute travel menu in the servo menu to the max throws in the book (23mm I think). If I only use elevator or aileron by itself, the surface moves something like 17mm at 100% rates if i remember correctly.

I usually look for the vertical stabilizer when I'm trying to orient the other models which was what i first looked for, but all i could see in my head was a pencil flying at 100mph. It got better once i started banking further and paying more attention to the canards. As Marktur mentioned, "winter" has come to South Florida so the weather is a beautiful 63 degrees but a little gusty. Forecast shows the winds should be calm (5-7 mph) this weekend so I'm hoping to get out to the field and get some more flight time on her.

[Evan D]

Good to see you on here James. Can you get us an update on the TV availability?

Wow! That is a ton of throw on a Delta. I fly it with about 50-60% on the roll surfaces now and she's still more than nimble. Regarding orientation, if the sun is in the wrong place, all models look silhouetted but I actually find the white of the canards easier to see.

[killickb]

O f course James’ eyes are at least 50 years younger than mine !
I too learnt not to cut motor wires, back in the Astro brushed days. With my FMS fan and ZTW ESC I am also having to shorten the motor/ESC wires but am cutting the ZTW wires. The actual bullet connection point will be right under the fin opening.
I bit the bullet and bought some Spectrum IC-5 connectors instead of using my stash of EC-5s as I can never get those connectors snapped into,the housings, even with the tool — and then some push in from the front and some from the rear ! Of course I am probably like many of us with way to many packs/motors/ESCs with EC-5 and a drawer full of various EC-5s ( an EC-5 is not an EC-5 is not an EC-5 !!!) to ever change 100%.

[Mizer67]

It certainly draws more energy but the gains are not minimal in my experience.

Do you have any data on the gains from changing the timing for thing like speed, vertical or static thrust? I'm a numbers guy and am not using the FW setup or I'd get some myself.

[radfordc]

Well, that's why you are not supposed to cut those wires and use the pre-tinned part of the motor wires. It's almost impossible to solder that stuff.

Asprin... https://electronics.stackexchange.co...ec%20in%20fact).

Seeing is believing... https://youtu.be/DDEPMdDcPOk

[Airguardian]

Do you have any data on the gains from changing the timing for thing like speed, vertical or static thrust? I'm a numbers guy and am not using the FW setup or I'd get some myself.

Sorry, haven't measured other than with my eyes and ears.

[kallend]

My 80mm FMS PRO is supposed to be delivered today.

"Supposed" being the operative word. It made it all the way from Hong Kong to my local post office, which has now lost it.