SAPAC Saab JAS-39 Are finally In
 

Got my hands on one of the first of the production models today, First Impression is good. More parts than I expected and of course minimal instructions, but enough to put it together if you take a little time to look at the pictures.

So far it's going together faster than I thought.

Hope to get this puppy in the air soon. They are in stock and available at;

http://homenhobbyshop.com/index.cfm?...2221&pageid=50
Check out the video of the prototype flying.

RE: SAPAC Saab JAS-39 Are finally In
 

Final installation of components and servo leads. Ready to finish the rear ection of Fuse. Careful alignment even with the guide pins but not to dificult to get together without the help of another set of hands. Wings are straight forward and careful glue management results with a clean bond. All servo leads routed and ESC installed. I used a UBEC for the radio and ready for the front half of the fuse.

RE: SAPAC Saab JAS-39 Are finally In
 

Any chance we can put a fixed landing gear on this puppy?
I hate to hand launch.. :(

RE: SAPAC Saab JAS-39 Are finally In
 

The aircraft comes with spring loaded struts, made from light weight aluminum, real cool, Haven't gotten that far yet.

RE: SAPAC Saab JAS-39 Are finally In
 

Back to building,
Work just seems to get in the way. I’ve attached the landing gear supports which also act as additional bracing for the wing joints. iInstalled the front steerable gear. Completed testing of all wiring, motor direction and servo arm movement.
Once the front intake ports are installed there will be limited access to the interior. I used double faced tape to secure the servos. The servo cavities snugly held the Hitec 65's that I am using. All gear is a go and the final addition of the canopy, intake ports and neat supplied ordinance is next.

RE: SAPAC Saab JAS-39 Are finally In
 

Have you maidened it yet? I have one too but I bought the ARF version. Planning to use a Wemotec Minifan and HET motor. Have you put your motor and fan on the meter and have you weighed it yet? Looking good so far.

Mike

RE: SAPAC Saab JAS-39 Are finally In
 

Back to building, The final components installed I used epoxy on the Canards for extra strenght. Had to be patient to be sure that they dried with the right angle. left alone they sagged a bit so I had to hold them up as they dried.
I added all the ordinance package for looks and extra weight fo the rear. I found it to be a bit nose heavy.
It weighted in at 47 oz without battery. A bit heaver than advertised. The battery I am using is a 4 cell 3300 EVO 25 at 13 oz overall flying weight will be 60oz. thats 3.75 pounds. WOW!
Did not get to the field this weekend to maiden. Planning to, later this week with video camera so we can post some videos of the stock setup performance.

Been selling quite a few of them, for the money it's a good size jet and the finished product is quire impressive. for more information go to:
http://www.homenhobbyshop.com/index....3879&pageid=50

Will post video as soon as I can.

RE: SAPAC Saab JAS-39 Are finally In
 

i have a lot of question about this plane, i just got it and some things are confusing, is anyone building and taking pics of the build here, thanks

RE: SAPAC Saab JAS-39 Are finally In
 

Yes, I posted pic's of the build. If you have any specific questions , please just ask!:eek:

RE: SAPAC Saab JAS-39 Are finally In
 

yes hapy you did, but you did not go into any detail which i always need. your pics were very helpful when i blew them up to a decent size.

the motor housing is giving me fits. the horseshoe shaped styrofoam the housing sits in has me baffled. i can see how it fits in the thing,

its trying to put it in the right half of the fuslage that gets me. even when i think its right and set the left half of the fuslage to mate with the right half

the fan falls out of the horseshoe shaped styrofoam.
is it glued in?

what keeps it from moving around?

do the wires from the motor exit the bottom or the top?

this thing is something i really want to do, but this arf is getting me[:@]

i always follow builds in these forums to put my jets together, but the lack of any detail on this one is making it too hard for my 62 year old eyes.

thanks, its appreciated for giving me an answer.:D

btw, i see you did the right half first, so im following your lead. its hard to tell from the pics but are your wires from the motor running

from the bottom of the fan housing?

also, how many and what size servo extensions did you use? did you use the rudder or not?

is a y harness needed? im going to leave the rudder off this plane, i cant see where it would need one. ill watch for someone flying this thing and then ask if its needed.

since you said it was nose heavy, im going to add my weight in the rudder servo hole then mix some epoxy with a little spackle and fill it in.

im repainting the plane anyway. my battery is a 4200 so i know its heavier than yours.,

i know i ask a lot of you here so please bear with me, id love to get it finished and shoot you some pics here.

again, thank you.

tom

RE: SAPAC Saab JAS-39 Are finally In
 

I used a bit of double sided tape to hold the fan unit in the U shaped housing, The ribs of the Fan housing lines up with the slots in the foam housing. With the thrust tube attached it stays in place. The fan wires exit out the bottom and runs along the bottow of the fuse forward. I used a 24 " extension on the rudder and two 12' extensions for the elevons.
I feel the rudder it too imprortant to omit but that's your choice.
I am using a 4 cell 3300 which weighs in at 13 oz. so it is a bit nose heavy. The prototype is set with the elevons up abit about 3mm or so. I hope to maiden this weekend but our field is closed due to a combat event. So I might have to wait till next week.

Hey I'm 59! [X(] 62 ain"t old!

RE: SAPAC Saab JAS-39 Are finally In
 

thanks so much for the info.

ill be waiting to hear how she flies especially if your flying it all stock.

RE: SAPAC Saab JAS-39 Are finally In
 

Well I finally broke down and got one of these baby's. I am putting it together as we speak. Will try and Take some pictures and give some informative instruction as I go along but don;t count on it too much as I might just get right into it and go!!!! Like what has been said so far and will look for the video to come out . Happy flying .

RE: SAPAC Saab JAS-39 Are finally In
 

You'll love it, I just wish the bad weather we're having will clear. Want to get the video done.
There is one video at;

www.homenhobbyshop.com

RE: SAPAC Saab JAS-39 Are finally In
 

dancing eagle

will you be building and flying the 70mm stock set up?

im looking forward to some build pics, good luck, im trying to get mine going now.

RE: SAPAC Saab JAS-39 Are finally In
 

Hey guys, we, the guys on Rcgroups.com were discussing that the fan should be placed in the back right under the vertical stab for c.g. issues.
There is one guy on the thread, Erenest, who had flown it and(has video) said it was nose heavy and thus had to add weight to the back because he had put the fan where the instructions said to put it (in the U shaped foam thingy). Since then he re-located the fan under the vertical stab but yet to hear from his flight report. http://www.rcgroups.com/forums/showt...829331&page=39 [and] http://www.rcgroups.com/forums/showt...829331&page=34
Well speaking of flight report, wel,l there is another rcgroup member who go's by the name 'Captain Carlton' who started his build with the fan in the back under the stab. Actually the plane prototype (which is shown on youtube.com by Eddiegigawatts) was designed to have the fan in that very spot but somehow it's been re-designed inside to the way it's sold now -don't ask why. Anyway, he whiped the plane together -which there is pics- and flown it! He said it flew so good just like the video on youtube under SAPAC GRIPEN. There are some good snapshots of him flying it but no video. http://www.rcgroups.com/forums/showt...9#post10314189 Check it out! Hey guys come to rcgroups.com youll love it!;)

RE: SAPAC Saab JAS-39 Are finally In
 

Finally maidened yesterday, light winds right down the runway and it was Hot, mid 90's and humidity about the same.

First takeoff attempt was aborted since the plane wouldn't rotate. We added a slight bit of tail weight and tried to adjust the gear to give the plane a better angle of attach and lifted the front a bit. Second run was more successful and she rotated with authority. Fight characteristics showed the aircraft to be very stable, speed was good, not breathtaking but fast enough. Rolls and jet type maneuvers are good and landing was uneventful.

I used an EVO 25C 3300 4 cell. got a good 4.5 minites. Battery got a bit hot due to lack of airflow and I will add an air vent to the rear of the battery compartment to alow a bit more airflow. I will also move the ESC further to the rear to get in the airflow of the intake.
The landing gear worked well but I found the wire base that the struts attach to are a bit weak. I plan on making new ones out of a stronger wire.
Other than that, I was quite pleased with the first flight. I wanted to keep it as stock as possible and not do all the mods that are not proven yet.

I do feel that the fan mounted futher back would be a big help on the nose heavy issue and I think the interior of the nose section could be hollowed out a bit to reduce weight without compromising structual integriety. I hated to have to add tail weight. But that's my 2 cents.

She looks great and attracted a lot of attention at the field. It's a good size, and you can see it.
I've been selling quite a few of these and now feel confident that anyone who buys one is going to be as happy as me!

We did video but I'm going on vacation and won't be able to post until I return.

Get yours at, www.homenhobbyshop.com

RE: SAPAC Saab JAS-39 Are finally In
 

That's great to hear. Good tip on the LG wire too. Thanks. So you're at 60oz on the stock motor and fan. Any vertical and high alfa like in Eddie's video on that.

RE: SAPAC Saab JAS-39 Are finally In
 

Hey guys thanks for all the information. I knew there was a reason that I had not gotten around to putting this puppy together yet. Yes I am doing the stock build as I got the order messed up and had to wait for the fan and motor. Thinking of changing the motor after hearing the flight report from happyjac. Also I believe that I will mount the fan in the stabb under the wing as apposed to the instructions. Have been having a time trying to get a Zero done and it just seems that I am always waiting on parts. Well I should have all my parts , and extra, soon as I went a little crazy and ordered a whole lot of extra servos , batteries , etc so I don;t have to wait on the next build. I do believe I will take some time in the build and offer a lot of pics and suggestions for what they will be worth. I can build like a champ but flying is still a learning process for me. However I have found out that ( after a mild crash ) foamies respond to a hair drier pretty well in the reshaping process. Crashed my Diamond F-18 and it blew apart from the cockpit to the nose , however it is almost back together. not much to look at right now but just about flyable. Have been using the hair drier to remold the front of the fuse that was in about 30 pieces. Not bad for a fix. I am not throwing away a 200 dollar jet because it crashed. Sad part of it all is that it was my error . switched of the tx and down it went. I had no idea what went wrong until I went to switch of the tx and it was already off. Happens to us over 50 guys sometimes. Will post again when building

RE: SAPAC Saab JAS-39 Are finally In
 

Vertical was decent. Did not try any Aplha moves yet. Just trying to be sure the stock set up will perform and meet everyones reasonable expectaions. We only had one battery and did alot of ground testing first. Then the rains came. Ya gotta love Florida, it rains every afternoon this time of year.

RE: SAPAC Saab JAS-39 Are finally In
 

Maidened mine this evening. What a fantastic plane. Absolutely no bad habits at all. Only issue was the previously mentioned weak landing gear wire. Mine flies with authority on 6s 2250 30c Rhino packs and a Wemo MiniFan with an HET 2w-25 motor and a 60 amp Hextronic esc. My new favorite plane!!!

Mike

RE: SAPAC Saab JAS-39 Are finally In
 

Hi guys. I have yet to get mine up yet. The first try confirmed that the landing gear is completly inadequate so I have cut out slots for grooved hardwood blocks and installed heavy wire gear. I also drilled out the nose gear strut and replace the stock wire which broke off during taxi tests.

I am very nervous about the indicated center of gravity which seems very far forward. Is it correct ?, also what controls throws you are using ?

Thanks

RE: SAPAC Saab JAS-39 Are finally In
 

The indicated CG is good. Puts it about at the front area of the big foam injection circles on the undersid of the wing. My throws are about 1" in either direction, so 2" total throw. Set up your dual rates for 50% of that and set up -40 on your expo.I have about 3-4mm of reflex dial in too. Don't be nervous about flying this plane. It's not a knee knocker at all. Remember too that if you haven't built it too heavy you don't have to fly at full throttle all of the time. Flies very slowly if you want it too.

Mike

http://www.youtube.com/watch?v=_4ZI7PsYpNM

RE: SAPAC Saab JAS-39 Are finally In
 

Mike ... thanks for the prompt reply. I will check my set up to conform to your recommendations and maiden tommorrow. I will let you know how it went.

Thanks again

RE: SAPAC Saab JAS-39 Are finally In
 

Finally got to maiden today after ESC issues. One flight completed. Got it up after a long run and it shot up like a rocket. I will have to increase the angle of attack while sitting on the gear .

Next flight will follow shortening to the length of the main gear struts and resseting the expo. Expo setting was way off (Mikes suggestion) and I now realise Futaba (+) expo is opposite to JR (-). It was a pretty hairly flight but I manged to get it down without incident.