New JAS-39 Gripen build + review

[ammo]

Following the F18 Superhornet, I've started putting together the Gripen

The delta wing layout says a higher speed envelope than the F18 while the canards in front will still retain good stall characteristics and stability.

I'll post the pictures in a while

[Alvin Roger]

Hi Ammo,

I like your F-18 build thread. Are you a vendor?

[Raven]

Hi Ammo,

I like your F-18 build thread. Are you a vendor?

Radio Control Sports (RCS)

[ammo]

New in box


Main body...


2 wing panels, prehinged....


Rudder, prehinged as well....


Front canards x2(a full moving one will be nice , nevermind, i'll live with this fixed one first)


Misc bits and pcs


Carnard slot on the fuselage


Alignment holes for the main wings


Canopy glued, but i think i gotta take a black marker and paint the lines to make it look better


Panel lines hehehe


Snake tube and wire for rudder pushrod

[ammo]

A look from the rear outlet, pretty clean short ducting as the fan unit is positioned at about the rear 1/3 of the duct. I think it should be faster than the F18 on the same power system.


The bottom skid protection, similar to the F18 also,


A good way to provide some protection as well as hide the esc and servo leads from exposed snagging dangers


Battery compartment.... i wonder where will the rx go...
Nosewheel is steerable as usual


Cheat ducts, only visible if you view it perpendicular from the side


ESC under cover, with some cooling holes... let's hope this unit is not a lemon

[Raven]

.... lol I saw the cheater hole!!

[ammo]

I used the contact cement provided, smear a layer on one side...


Press them on firmly...


Open apart and let them dry for a while, eg 5-10 mins


In the meantime, i'll do the same to the rudder and canards
Not much to do on the rudder, just position the pushrod from the fuselage snake to the rudder section..
Note the clean convergence ducting for the front section. I read it's quite important to have a good V convergence, compared with just an empty pocket right after the front entry which creates a lot of turbulence

[ammo]

Once the contact cement has dried to a tacky feel, simply put the wings, canards, rudder back in place again. Press firmly and it should be stuck pretty good now...
Rudder linkage tightened and excess pushrod is cut off


Install the landing gear...


Underside view


Installing the fan section retainer is simply 2 pcs of molded plastic with a self tapping screw.


Lifting the tab at the front of the skid protector shows the all the servo tabs and a space which i can fit in the receiver.



Aileron linkages, straight forward 2 mins job


Assembly done, it's one extremely fast job!

[ammo]

Sadly today is a rainy day and I don't get a chance to maiden the Gripen...

[ammo]

There was a break from the rain on Saturday but the winds were blowing pretty hard. I had bad experience flying light models in gusty winds and since it's a maiden flight, it just adds to the complications. Not forgetting the trimming and getting used to that we face for new planes...

I waited until the last hour of light, and the wind did seem to weaken 'a little', but given the only window since the entire week, i just had to give it a go. Arrived at my usual field at 6pm, quickly took some pics, but most didn't turn out well due to the natural lighting dwindling. The soil was pretty soft as well from the previous few days of rain, just taxing around left plenty of track lines all over. This proved to be something i overlooked later on.

Usual position, full throttle into the open, there was a pretty narrow track of bare soil among the grass which i try to keep the plane lined up on for take offs. The Gripen rolled off smoothly, but it did appear to me the speed was kind of slow given it had the same power system as the F18 SuperHornet. A bit too late, i'm sort of commited with the speed now. It didn't have enough speed until it reached the end of the soil track and into the grassy areas. a bounce or two helped send it into the air from there. It start to roll to the left and i reacted too slowly, the Gripen quickly disappeared behind a tree on the left of the runway, est 40ft up. 'S**t!' was the word to jump out of my mouth. Since i can't see it, i can only cut throttle and hold up elevator and hope for the best

With a sunken heart, i walked towards the tree and saw the tail of the gripen pointing up from the grass patch a distance away.... that's it....

Surprisingly, the Gripen seems to have crashed landed into a grassy depression of some sort in the field and amazingly, the nosecone suffered one creaseline, that's all! Boy, must i thank my lucky stars for that...

Checked out all the controls and linkages, nothing was wrong at all, so i took it back to the take off strip again and this time, walked further back to squeeze a bit more room for the takeoff run.

Apparently, the wet soil added quite a lot of rolling resistance and hence the slower speed :p forgot about that point when i was having fun taxing around making those tracklines...

Trimmed in some up elevator and right aileron, 2nd take off was uneventful this time! Took her around for a few circuits at full throttle, checking out for any misbehaviour, all was good! Slowed down pretty well while still retaining control without dropping off in stall. It just mushed it's head when i slow it into a stall, no bad habits

Landing is pretty much a piece of cake, just like the F18

After letting the motor and esc cool down for a while, i load up a fresh pack and took it for another flight. Rolls and loops, inverted flights was smooth as silk I ran out of sufficient sunlight by the time i am done with the 2nd pack... This plane's a keeper!

Here's some pics from the ground, i was alone for the flight so no inflight pics :p

[Gt2C<Kudou>]

Conclusion Please...=)

So, wads ur conclusion? which 1 is better? this 1 or the f18??

There was a break from the rain on Saturday but the winds were blowing pretty hard. I had bad experience flying light models in gusty winds and since it's a maiden flight, it just adds to the complications. Not forgetting the trimming and getting used to that we face for new planes...

I waited until the last hour of light, and the wind did seem to weaken 'a little', but given the only window since the entire week, i just had to give it a go. Arrived at my usual field at 6pm, quickly took some pics, but most didn't turn out well due to the natural lighting dwindling. The soil was pretty soft as well from the previous few days of rain, just taxing around left plenty of track lines all over. This proved to be something i overlooked later on.

Usual position, full throttle into the open, there was a pretty narrow track of bare soil among the grass which i try to keep the plane lined up on for take offs. The Gripen rolled off smoothly, but it did appear to me the speed was kind of slow given it had the same power system as the F18 SuperHornet. A bit too late, i'm sort of commited with the speed now. It didn't have enough speed until it reached the end of the soil track and into the grassy areas. a bounce or two helped send it into the air from there. It start to roll to the left and i reacted too slowly, the Gripen quickly disappeared behind a tree on the left of the runway, est 40ft up. 'S**t!' was the word to jump out of my mouth. Since i can't see it, i can only cut throttle and hold up elevator and hope for the best

With a sunken heart, i walked towards the tree and saw the tail of the gripen pointing up from the grass patch a distance away.... that's it....

Surprisingly, the Gripen seems to have crashed landed into a grassy depression of some sort in the field and amazingly, the nosecone suffered one creaseline, that's all! Boy, must i thank my lucky stars for that...

Checked out all the controls and linkages, nothing was wrong at all, so i took it back to the take off strip again and this time, walked further back to squeeze a bit more room for the takeoff run.

Apparently, the wet soil added quite a lot of rolling resistance and hence the slower speed :p forgot about that point when i was having fun taxing around making those tracklines...

Trimmed in some up elevator and right aileron, 2nd take off was uneventful this time! Took her around for a few circuits at full throttle, checking out for any misbehaviour, all was good! Slowed down pretty well while still retaining control without dropping off in stall. It just mushed it's head when i slow it into a stall, no bad habits

Landing is pretty much a piece of cake, just like the F18

After letting the motor and esc cool down for a while, i load up a fresh pack and took it for another flight. Rolls and loops, inverted flights was smooth as silk I ran out of sufficient sunlight by the time i am done with the 2nd pack... This plane's a keeper!

Here's some pics from the ground, i was alone for the flight so no inflight pics :p

[ammo]

So, wads ur conclusion? which 1 is better? this 1 or the f18??

That is a very difficult question to answer..... Get BOTH!!!

[Gt2C<Kudou>]

That is a very difficult question to answer..... Get BOTH!!!

Tads even more difficult to answer cuz no money

but which 1 gives a better handling? and speed... And if im not mistaken u crased both of them allready

[ammo]

Yup, i crashed both of them on the first flights, the F18 was due to the faulty esc, the gripen was becos i took off behind a tree

Don't ask me why my maidens always like that....

Handling wise both do very well, it's not easy for me to answer that question at all. If this is your first experience with a edf+ delta shape planes, then the F18 will be easier. If you have experience with delta shape planes, then the gripen won't be an alarming surprise to you in terms of the elevons. But i would say go for whichever you prefer the looks.

[Alvin Roger]

Sorry to say that, you claimed that both are easy to fly in your reviews but why ended up crashing both on their first flight?
Now I had starting to have doubt about your reviews. Are they really that easy to fly or just another way of pushing sales?