Roban - World Class Scale Helicopters

You must Sign-in or Register to post messages in the Hobby Squawk community
Registration is FREE and only takes a few moments

Register now

Announcement

Collapse
No announcement yet.

Official Freewing JAS 39 Gripen 80mm EDF Jet

Collapse
X
Collapse
First Prev Next Last
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Hi hope the thrust vectoring unit turn up before spring because I have told every one in my club who would listen about this and I am starting to have people ask me through you are going to fit this kit you keep banging on about ? Foot note don’t jump to early

    Comment


    • Originally posted by Evan D View Post
      Between being a delta, canards, thrust vectoring and 8s power I’m not bored.

      Very nice. where du you have the batteries og what is the CG? Is it flying good?
      What is the total weight of your Gripen? Weight, size of the batteries?
      I`m considder to go 8s or even 12s if I find a good solution for the CG...

      Comment


      • Originally posted by kallend View Post

        Here is the revised version. Same Thingiverse location.
        Looks great :D
        Freewing A-10 turbine conversion: http://fb.me/FreewingA10TurbineConversion

        Comment


        • Hard questions... I don't have the answers to the total weight. I am balanced 15-18mm behind the marks under the wings.5200 6+2 @ 880g. 12S can work. I have 3500 6S 60C packs that fit. They are 890g for two.


          Originally posted by rms View Post


          Very nice. where du you have the batteries og what is the CG? Is it flying good?
          What is the total weight of your Gripen? Weight, size of the batteries?
          I`m considder to go 8s or even 12s if I find a good solution for the CG...

          Comment


          • Originally posted by Evan D View Post
            Hard questions... I don't have the answers to the total weight. I am balanced 15-18mm behind the marks under the wings.5200 6+2 @ 880g. 12S can work. I have 3500 6S 60C packs that fit. They are 890g for two.
            Are you using 6s not 4s x 2 batteries? Do you have both batteries in front?
            15-18mm behind CG recomandation?


            Comment


            • I am using a 6S plus a 2S. They are one atop the other. I'll find a picture. I post more in RCG than here and have more information and pictures there.

              There is a balance mark molded in the foam under the wing that I use as a reference. I am 15-18mm behind the mark.

              Click image for larger version

Name:	Battery.jpg
Views:	242
Size:	81.3 KB
ID:	293130


              Originally posted by rms View Post
              Are you using 6s not 4s x 2 batteries? Do you have both batteries in front?
              15-18mm behind CG recomandation?

              Comment


              • Originally posted by Evan D View Post
                There is a balance mark molded in the foam under the wing that I use as a reference. I am 15-18mm behind the mark.

                Click image for larger version

Name:	Battery.jpg
Views:	242
Size:	81.3 KB
ID:	293130
                Is your EDF a lot heavier than the 6s one? I can't get my battery as far back as yours without cutting into the foam that separates the internal compartment from the air intake plenum. I'm using the Gens Ace 5000. I don't want to cut into the foam to get the battery further back so I've added some tail weight and that only achieves balance at the marks (and that's with the VT nozzle installed). I see you've got the Assan steering gyro. How does that work for you? I also have one on mine but some say it's not required. I can't maiden till spring.

                Comment


                • The picture was taken before the TVs. I would say it's average weight. The JF is about the same as the stock fan and shroud. The HET may be a little more than the stock inrunner but not much. I have a Turnigy 120HV ESC about the same weight as the stock 100A HW. My batteries and series adapter are 880g. Paint added a little, maybe more paint aft of the balance point??? I think I added 75-80g of lead in the stock rear fuselage to balance it at 15-18mm behind the mark. The TV rear part is 13g heavier than the old rear with lead. My batteries are 48mm wide so maybe I am able to push them back a bit more?

                  My receiver is aft under the battery tray. I shortened any extensions I could. My satellite us under the vertical fin. I do have a steering gyro up front and if I was building it again I wouldn't use it since the Gripen's forward gear position isn't as tippy as I thought it would be.. What is the weight and dimensions of your battery? I assume you have it laying in a way that's the most narrow.

                  Edit... if you are using the 45C battery yours is narrower and should go back further but are 20mm longer than mine so extend further forward... But they are only 716g? But they have others with other C ratings...

                  Comment


                  • My Gens are 45C, 725g, 45mm X 45mm X 155mm. It's shoved right back to where the foam angles inward. I didn't weigh the weight, just kept adding till it balanced at the marks. It already looked like a lot so I didn't add any more to get the balance aft of the marks. Will fly it first (carefully) and see if I like it that way. It just seems like a terrible thing to have to add so much weight.
                    I may change my mind about the Assan. I have other planes that are quite darty on the ground that can use one. (I did buy the 5 pack.)
                    Thanks.

                    Comment


                    • How much weight did you add?

                      Comment


                      • I never weighed it and now their stuck onto the plane. I used thin lead sheets that we used to use for radioisotope shielding when I worked in medical research. The sheets are about 2mm thick and I cut out what I estimate to be a strip about 3/4" wide and 12" long, cut into 3 pieces, 2 of which was doubled over. Weighing a similar strip of lead, it was 65g.
                        You can see the 2 double thickness strips on the bottom. There is one more single layer strip on top.
                        Click image for larger version

Name:	IMG_3789.JPG
Views:	240
Size:	81.6 KB
ID:	293162

                        Comment


                        • That is very surprising. I would have never guessed you'd need that. Maybe when John makes a 3D printed exhaust it'll let you remove the lead.

                          Not liking the foam nozzle I put the plastic from my old one on the TV nozzle today...


                          . Click image for larger version

Name:	F2ADBD4E-0DDF-4A80-B795-B7CD14D5C47E.jpg
Views:	241
Size:	87.4 KB
ID:	293168Click image for larger version

Name:	ECE74451-5D5B-48E0-94DA-CAEE8DC49E03.jpeg
Views:	224
Size:	90.3 KB
ID:	293169Click image for larger version

Name:	56B0B77B-E246-4918-989D-8E0C5F89C966.jpeg
Views:	227
Size:	95.3 KB
ID:	293170

                          Comment


                          • One the one hand, 65g isn't a huge amount of weight. It just looks like a lot and it's awkward. I suppose when it's flying, they aren't that noticeable.

                            Comment


                            • Is it worth buying the Gripen. I have the high performance Mirage with the 80mm inrunner motor.and by all accounts the Mirage I am told fly better then the Gripen. Would I be wasting my money buying the Gripen {if they ever come back in stock in Europe).
                              ​​​​

                              Comment


                              • Hey which is better, the L-39 or the T-33...


                                They are two different aircraft and fly different. If you want to compare the non TV Gripen stock PNP to the stock HP Mirage and have limited funds it would be $429 to $325 and imo the Mirage would be the no brainer, especially if you want a fast little sports car of a jet. But if you wanted something newer, something more all around, something you can put bigger batteries in , something you can add TVs to... Well then the Gripen would be my choice. Really my only gripe is with the power. 6S is just not the level of power THAT I WANT... Add TVs and it robs some of that power... There it is... Underpowered especially with the TVs, I said it... But that's my opinion...

                                At the end of the day they are two different planes with different skill sets and I'd have to say buy both and see which you fly more.

                                You already have the Mirage... When I bought my Gripen I had two Mirages, I love them... I crashed once since so I only have one now, a HP one... I never fly it anymore, that's unfair... I don't fly it much though...


                                Get a Gripen and get the TVs... And make it 8S.

                                Comment


                                • Originally posted by Evan D View Post

                                  Get a Gripen and get the TVs... And make it 8S.
                                  What's your 8S setup? I'm flying it in Colorado and 6S isn't cutting it. I thought it was slightly underpowered at sea level but up here in the thin air, no way is 6S enough. I have the stock 8S system in the Raptor but that's my only experience with anything higher than 6S.

                                  Comment


                                  • JF/ HET 1738kV Plush 120HV ESC 6+2 5200 lipo.

                                    Comment


                                    • Originally posted by Evan D View Post
                                      JF/ HET 1738kV Plush 120HV ESC 6+2 5200 lipo.
                                      Thanks Evan. I see you have the HS lipos. Happy with them? I used 6+2 Admiral 5000's in the Raptor.

                                      Comment


                                      • Not really. I was with earlier ones but later ones just aren’t holding up as well. I’m using power hobby ones right now in 6s and am looking for better 2s. The Admirals are too heavy. I don’t think they’ll fit either.

                                        Comment


                                        • I`m using this SLS 6s 3500 witch was the lighest I could find for a normal price. Also that they come out good in test. I have been very satisfied. The 6s 3500 30c id 505gram and the 2s 3500 is 198gram....something I consider to get 8s. And make space in the wing/ fuselage to keep the CG aft.
                                          https://www.stefansliposhop.de/en/ba...60c::1675.html
                                          I fly with this 6s witch is a light setup, aft CG, no lead in the tail gives very good handling on the Gripen. Flying weight 2860gram
                                          A film of my Gripen.
                                          https://www.youtube.com/watch?v=oYnch4159og&t=6s

                                          Comment

                                          Working...
                                          X