Official Freewing JAS 39 Gripen 80mm EDF Jet

[Evan D]

As noted balance and adding tail weight has been heavily discussed on this thread and the RCG one. Most added 80-100g to get a good balance and the balance most have found to their liking has been 10-15mm behind the book CG. Adding the TV tail makes the balance about perfect, like they designed it to have it.

[kallend]

Adding the TV tail makes the balance about perfect, like they designed it to have it.

Wishing now I had ordered it from Raymond instead of patiently waiting for MRC to have it.

[janmb]

As noted balance and adding tail weight has been heavily discussed on this thread and the RCG one. Most added 80-100g to get a good balance and the balance most have found to their liking has been 10-15mm behind the book CG. Adding the TV tail makes the balance about perfect, like they designed it to have it.

If combined with very light batteries, yes.

[Evan D]

"Very light batteries"... depends on your definition. Mine (I'm 8S) are 880g, not what I would call very light but I realize my set up is not stock. The TV unit weighed more than the portion of the fuselage it replaced plus the 80g of lead I added so for me it was perfect. And with that I am, and was, significantly behind the book CG. I don't remember, Jan, what was your set up? Did you put the TVs on it before you crashed it (I seem to recall you crashed or that may have been Jandro) and where were you balancing it at?

[janmb]

"Very light batteries"... depends on your definition. Mine (I'm 8S) are 880g, not what I would call very light but I realize my set up is not stock. The TV unit weighed more than the portion of the fuselage it replaced plus the 80g of lead I added so for me it was perfect. And with that I am, and was, significantly behind the book CG. I don't remember, Jan, what was your set up? Did you put the TVs on it before you crashed it (I seem to recall you crashed or that may have been Jandro) and where were you balancing it at?

Haven't had any mishaps with my Gripen. Only flew it four flights on EDF power, without vectoring, before converting it.

I never had the stock EDF in it either, so my experiences are probably not representative. I had additional CG challenges due to a lighter than stock fan.

Then again it's no secret I love aft cg more than most :)

[Denar76]

One of the few Gripens that made a touch and go in the EU warehouse arrived in Sweden today...
It will get a Swedish livery before airborne because... well I guess it's pretty obvious...

Thanks for a lot of useful tips and discussions in the thread so far...

Dennis

[Pogo]

The nice thing about a fictional demo scheme is it can keep evolving. I added rondels to the bottom of the canards today, vinyl from somewhere I've had for years in the stash.
Tom

[Pogo]

Due to the extra weight of the cockpit the model still needed lead in the tail so I decided to attempt making the air (or speed) brakes functional and add useful weight. This looks pretty rough but some filler, paint, and covers will help- but at least it works!
I fooled around with the hinging and eventually put the bottom one outside the skin- not scale but it's the only way the panel would open. I don't think SAAB got it right...
Tom

[Gary S.]

This is how I fixed the weight distribution issue.... Moved the motor back. 8S no counterweight.

[Evan D]

Nice! When you can more info please.

[James]

The Gripen TV unit is available now: https://www.motionrc.com/products/fr...or-upgrade-set

[Evan D]

Thanks! I ordered them, Gripen and MiG earlier. Life is good.

[TangoVector]

Originally I was going to get a TV-unit straight away, now it won't fit since it is too narrow. Being nose heavy will not be a problem I hope.

[Evan D]

Why are you saying too narrow TV? What did you do?

Originally I was going to get a TV-unit straight away, now it won't fit since it is too narrow. Being nose heavy will not be a problem I hope.

[kallend]

The Gripen TV unit is available now: https://www.motionrc.com/products/fr...or-upgrade-set

Ordered within minutes of the email from MRC. As I live in northern IL, delivery is usually next day.

[Evan D]

Hmm I just realized even though I signed up to be notified for both the Gripen and MiG TVs I haven’t received a notice for either...

[TangoVector]

Why are you saying too narrow TV? What did you do?

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).

[Mizer67]

I look forward to seeing the final result TangoVector.

Probably not something I will attempt, but I applaud the effort and hope you can get a good performance boost from the 90mm.

[Marco Polo]

Hmm I just realized even though I signed up to be notified for both the Gripen and MiG TVs I haven’t received a notice for either...

See this post on Motion's website:

https://www.motionrc.com/blogs/motion-rc-blog/i-signed-up-for-back-in-stock-notify-but-i-didn-t-get-an-email-when-the-product-came-back-in-stock-why-did-this-happen

[Evan D]

Interesting, hard to believe I wasn’t early to sign up though. Thanks.