Official Freewing JAS 39 Gripen 80mm EDF Jet

[Airguardian]

FWIW, hovering the jet is easy enough to pull at some altitude with a good, well set-up gyro on... The tricky part is to do that just a few meters from the ground, THAT is indeed tricky and you may crash if you attempt it without practicing a lot first at higher altitudes and getting a good hang of how the jet behaves in hover and the kind of inputs it takes to control it there.

[paulrkytek]

I wish motion sold the Su35 as an ARF plus...

San I just bought the airframe and suspension bits from the spares catalogue then just bought the servos, escs, fms 1900kv fans separate becs wiring etc etc elsewhere, you will then get a true more than 1:1 thrust to weight ratio which if you have the skills ( which I do not) you can vertical hover as per Air Guardian videos . The question is do you have both the time and the inclination to do it ?

Freewing SU35. 1080mm ws, 1610 long. 2 number FMS70mm 3060 1900kv 12blade in-runners 2.6-2.7kg, 2xHobbywing skywalker 80amp escs.
5000mah Turnigy 60-120c 6s 825g flight time 3 to 3.5 mins. 50% expo on everything. Separate rx bec and 2s battery, 10ch rx. Horizontal stab servos Turnigy DMC809 19.5gm 3.8kgf .07 sec digital metal gear ball bearing servos . rudders ,3 vector thrusts 13.5g 2.0KGF Racerstar MG90. Flaperons Corona DS939 13.5g MG 2.5kgKGF. Total completed all up flying weight 3450gms. Thrust 5.4kg ( static FMS figures ) or 1.5 to 1. Assume actual thrust at 70% static =3.78kg which is 1.1 to 1 actual thrust

[SanExup]

I wish motion sold the Su35 as an ARF plus...

[kallend]

Hi, I'm thinking of getting the Gripen as ARF version. Ideally I want an EDF to get a thrust to weight ratio above 1. With the EDFs I checked it seems to be a very close call to get there. My question, how heavy is the ARF Version? Motionrc states 2350g for both Version PNP and ARF. How much extra weight would the thrust vectoring set add?

Thank You and best regards

Gripen is not the way to go for reasons described above.

Get a Sukhoi 35 ARF Plus with FMS PRO fans, T/W >1, full 3d vectored thrust. Inexpensive (everything being relative, of course).

[Airguardian]

Technically, a jet may still be able to roll without 'VT-roll' because the air gets dragged around the exhaust and flows over the wings, so some deltawing jets with large control surfaces close enough to the nozzle still retain some roll authority in hover. That said, the FW Gripen with the 'handicapped elevons' that FW designed this jet with (rather small in chord and not full span), plus the fact that the Gripen nozzle sits further aft from the wings on the Gripen... I wouldn't expect it to have that sort of redeeming feature ;)

[xviper]

The main reason to have more thrust than weight is so the plane can hover in a vertical attitude and with only one VT nozzle, there is no roll control when there is no air going over the control surfaces. The one jet that I know of (single TV nozzle) that claims to have such a thrust/weight ratio is the Flex Innovation FlexJet TV. It flies on 8s and has just over 1:1 T/W. It can't hover for long before it starts to roll uncontrollably. It needs just a little bit of forward speed for the control surfaces to work. If you're not going to hover, you don't need more than 1:1 T/W. At or near 1:1 is plenty for all kinds of 3D tricks. Even the stock Gripen can do weird and crazy things with TV. But then, with these things, it's not always a matter of "need". If you want it and gotta have it, that's another story.

[Evan D]

I think your biggest mistake there is assuming that the FMS EDF unit makes 3550g of thrust. Most spec'ed thrust numbers are either theoretical or if actual it's with the unit not in a plane.

[Sam78EDMO]

I have all this info in the RCG thread.

The TV unit weighs 164g. The stock back part weighs 74g. Extensions are 17g.

The TV unit robs about 10% of the thrust you have with a non TV'ed Gripen.

In my opinion if you want more than 1:1 you need to go 8S.

That thrust reduction kills it otherwise it could work. A rough calculation.

2350g (pnp without lipo according to motion)
- 354g EDF (according to rccastle)
- 80g PNP ESC (rough estimation)
- 50g removing some scale parts like antennas and pilot, (rough estimation)

That would be 1866g

+ 90g TV nozzle
+ 320g FMS 80mm EDF
+ 92g Flyfun 120A ESC
+ 833g light SLS 6s/7000ma/h lipo
+ 50g receiver/telemetry/gyro etc.

That would add up to 3251g with the FMS having 3550g of thrust - 10% = 3195 of thrust
Close call maybe there is a little bit more to remove or to replace with lighter parts.

[Evan D]

I have all this info in the RCG thread.

The TV unit weighs 164g. The stock back part weighs 74g. Extensions are 17g.

The TV unit robs about 10% of the thrust you have with a non TV'ed Gripen.

In my opinion if you want more than 1:1 you need to go 8S.

[Sam78EDMO]

Hi, I'm thinking of getting the Gripen as ARF version. Ideally I want an EDF to get a thrust to weight ratio above 1. With the EDFs I checked it seems to be a very close call to get there. My question, how heavy is the ARF Version? Motionrc states 2350g for both Version PNP and ARF. How much extra weight would the thrust vectoring set add?

Thank You and best regards

[Evan D]

PNP...

[Crippe1991]

Hi I have a question about the TV for the Gripen. To install it do I need to buy servo extensions or is the TV a pnp upgrade?

[Airguardian]

Always thought FW should have made this a 90mm bird from the get go :)

Great job!

New Heavy Metal Gripen video just posted!

[Gary S.]

[Gary S.]

https://youtu.be/0ZvF6nUU6LM

[Gary S.]

Very impressive, Both the mods and your results.

Evan, That is a tremendous compliment. As you are one of my great modding heroes/ inspirations. TY

[Evan D]

Very impressive, Both the mods and your results.

[Gary S.]

My Gripen has had a great life and was already highly modded. So I was switching all my TX RX over to FrSky X20s and....well I decided to go from 80mm 8s to 10s 90mm. (lots more modding) Just had my first 6 test flights and decided to do as speed check because its moving really fast....

[kallend]

Let’s Get HIGH ALPHA and LOW
With the 80mm Gripen from Motion RC and Freewing.

TURN IT UP 🔊

Very nice, but it needs an afterburner.

[xviper]

Let’s Get HIGH ALPHA and LOW
With the 80mm Gripen from Motion RC and Freewing.

TURN IT UP 🔊

https://youtu.be/Q3TTII8MxrQ

VERY artistic and well done. The snow in the background is a nice touch.