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 Black Horse 1724mm Dornier DO335 Pfeil ("Arrow") Thread

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

  • Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

    Joe
    Platt: fw190d9 Dynaflite:PT-19 IMP:Macchi202 ESM:fw190 ESM:Tank, Hien Jackson:DH-2 BH:macchi200 Extr:fw190 Holman:me109F H9spit2 FL:F4u,spit 9 FW:me262 GP:us60, Stuka, cub, F4u PZ:me109, albi EF Hurri, T-28 FMS: 2x fw190, me109 Lone Star:Skat Kat RSCombat:2xfw190d9

    Comment


    • Originally posted by paladin View Post
      Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

      Joe
      The the prop will be turning in the same direction as the tractor prop, right, and not counter-rotating? I would think that non counter rotating props would probably wouldn't have much a negative effect on yaw (P-factor) in the tractor/pusher config, but would probably give you a very noticeable difference in roll rate to the left versus right.
      ---
      Warbirder

      Comment


      • Originally posted by paladin View Post
        Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

        Joe
        On the DH-2 it wouldn't cause a problem mainly because the prop is basically in the center of the airframe.

        On the 335, what you are planning, might be a problem. Alpha indicated that the plane was designed to have contra-rotating props. The front CCW, as viewed from the front and the rear CW as viewed from the front.

        Both motor mounts have thrust offset built in for that configuration. If the rear were rotating in the opposite direction, it might amplify or add to the P-factor already acting on the tail surfaces. It may even want to induce a roll tendency to the left, as Oxotik indicated. And there may be other affects that don't come to mind at the moment.

        Comment


        • Started assembling the Do-335 this weekend.

          Fairly impressed with the kit. Very good build quality. Some details could be nit picked, but the overall effect is nice.

          I like the weathered detailed covering, but would be nice if it were not quite so dark. Ought to look better out in the sunlight.

          Powerwise, going with a pair of GForce D5055 400Kv motors and Hobbywing 80 amp ESCs. Master Airscrew 16x10x3 props, might cut down to 15” if needed. Undecided on the ultimate spinner solution so far, but 3D printing is attractive. Servos are a mix of what I have on hand and available. Using the recommended Xwave retracts.

          I dismounted the instrument panel so I could mask off the dials and gauges (computer cut vinyl) and anything that is behind glass and paint the rest of the clear panel grey and black.

          Not going to go too crazy with extra details. The goal is to get it in the air in a few weeks.

          Comment


          • 5055-400s, 16x10x3 props, 6S batteries are a good power train for the Do-335. You could probably get by with 60A ESCs, but you wouldn’t have much margin over peak current draw.
            ---
            Warbirder

            Comment


            • I am in...

              Going for the following set up:
              DX8 Gen 2 Tx
              Spektrum 6 channel Rx
              Xwave RM400-90 Electronic Retracts
              Hitec HS-645MG Ultra Torque Ball Bearing Metal Gear Standard Servos
              ZTW 18A BEC / UBEC - or separate isolated Rx battery depending on CG
              ZTW Mantis 85A ESC
              Flight Line 5055 390Kv Motors
              16x10x3 Pull/Push props
              6s 45c 5200mAh LiPo

              I just finished a nearly two months of assembly of a SeaGull Cessna Skymaster 336...need to get that aircraft maidened and sorted out before starting this assembly

              Still looking for some three blade spinners....might have to give TrueTurn the call

              https://www.warhistoryonline.com/mil...3LEJ27ZBEWP_XU

              TwistedGrin

              Comment


              • Quick study on LiPo mAh sizes reveals the following:
                Spektrum 22.2V 7000mAh 6S 30C Smart LiPo Battery: IC5 / SPMX70006S30 weight grams = 890g ...the form factor should fit nicely in the forward battery tray with plenty of room for balancing. I am following Oxotonic's lead for assembly and electronics packages....his dual CNHL 3s 30c 8000mAh package should be about 1182grams. He stated room to move those two LiPo's back some for less nose heavy scenario....this "Might" suggest the SPMX70006s30 LiPo will have enough room to adjust for COG most likely forward center of the battery tray. I like the idea of a single LiPo as it simplifies the wiring harness for dual ESC's - less wiring and less weight again. He still has 1000mAh more flight time though!!

                TwistedGrin

                Comment


                • Originally posted by Oxotnik View Post
                  5055-400s, 16x10x3 props, 6S batteries are a good power train for the Do-335. You could probably get by with 60A ESCs, but you wouldn’t have much margin over peak current draw.
                  Here is the Texas heat, I always have some extra capacity in my ESCs, whenever possible. It was over 100 at an regional warbird fly in I went to last weekend.

                  Comment


                  • Originally posted by tab28682 View Post

                    Here is the Texas heat, I always have some extra capacity in my ESCs, whenever possible. It was over 100 at an regional warbird fly in I went to last weekend.
                    Saturday before the cold front blasted through us....Greater Southwest Aero Modelers was probably heat indexed at 109...ambient 101.....could smell the grass drying up and the heat haze was nasty.

                    TwistedGrin AMA club 1140

                    Comment


                    • Originally posted by TwistedGrin View Post

                      Saturday before the cold front blasted through us....Greater Southwest Aero Modelers was probably heat indexed at 109...ambient 101.....could smell the grass drying up and the heat haze was nasty.

                      TwistedGrin AMA club 1140
                      I was at the Shreveport Warbirds for Warriors fly in. Just over 100 there, but heat index there with the humidity was about 106.

                      in any case, worth doing what you can to help keep heat stress down on all parts of an electric power system around here in the summer

                      Comment


                      • Received my spinners, reamed out the prop to fit the FreeWing Prop shaft adapter. It has about three threads exposed to make contact. It will tighten down....but I am not confident with this. Contemplating counter sinking into the MAS prop hub to allow the prop nut to get a couple more threads for insurance. I am now looking for a huge bit that will do the job.....maybe use a wood bit to dig into the prop hub material?

                        UPDATE: Looking into flat bottom end mill bit for this .....waiving off from Wood Working flat side bits

                        TwistedGrin
                        Attached Files

                        Comment


                        • I'm very much enjoying my Pfeil, even if it isn't the kind of model you bring out every trip -- sort of a "special occasion" model. I'm feeling much more comfortable flying it, and especially landing it. This video is from last weekend. The second flight landed right on the geotex centerline (I swear!). These were the first two flights with the new nose strut, a modified Freewing 80mm A-10 part, with the same Robart scale wheel as before. It has some "give" in the oleo which I think makes a difference. I'm on the hunt for equally nice main strut oleos.

                          I've been flying with Roaring Top 6s-32c 6250's. But it's finally dawned on me that with two motors sucking off of one lipo, I really should be using a much higher C lipo and have ordered a 65c 6200 -- I have high hopes that this will make a noticeable difference.


                          Comment


                          • Contemplating counter sinking into the MAS prop hub to allow the prop nut to get a couple more threads for insurance.
                            I'm no expert (but I know some, haha). But I think your problem goes beyond getting "a couple more threads". Unless I'm not seeing things correctly, your aluminum spinner base plate is sitting on top of the round portion of the motor shaft base (you've enlarged the hole in the spinner base to fit over the hex portion, if I understand correctly). You may have the more square shaped base (rounded corners), but same issue.

                            This doesn't seem to be enough surface area for the spinner to contact to remain tight, without having the hex shape to engage any more. When I designed my 3D spinners to work with that motor shaft, they took into account the hex as well as the round base portion. These spinners are still working fine, knock on wood -- er, PLA.

                            I guess you won't know until you try it -- might be worth setting up on a test stand first?


                            Click image for larger version

Name:	FL F4U motor shaft.jpg
Views:	665
Size:	45.0 KB
ID:	273849Click image for larger version

Name:	image_61128.jpg
Views:	757
Size:	78.6 KB
ID:	273845

                            Comment


                            • Mr. Smoothie - You are on target....I have NOT drilled my props yet. My spinner back plate fits perfectly flat onto the original FlightLine propshaft adapter. However I am second guessing my strategies:

                              A. Use the original FlightLine motor propshaft adapter (I have four of them at the ready)
                              1. Score or groove the prop shaft adapter face to provide positive surface friction with the spinner back plate surface
                              2. Drill and pin the spinner back plate to the prop shaft adapter
                              3. Counter sink the propeller hub to expose more thread for the prop-nut
                              i. Mill down the propshaft adapter face to allow more threads exposed

                              2. Use the FlightLine 1600mm Corsair propshaft adapter (I have two of them at the ready)
                              A. Use your 3D Print files on somebody's machine
                              B. Ream the prop for larger prop shaft diameter

                              If I choose option 2 I need to know and order the correct material for someone's 3D printer and get your files.....and settings for all of it. There are several pilots I know of in Fort Worth Tx who have 3D printers....but I don't understand enough about them to know what questions to ask......I am assuming there are settings, granularity, heat, speed, size capabilities variables to deal with?

                              TwistedGrin

                              Comment


                              • I uploaded a zip file containing all of the 3D files I created for my Dornier on my RCG built log -- on one of the later pages somewhere:



                                Comment


                                • 10:4 Thank you MrSmoothie.....I over looked the post somehow.....thanks for sharing your excellence sir!

                                  TwistedGrin

                                  Comment


                                  • I have made great progress on my DO 335....I have opened up the manual...and C.A.'d the Ailerons and Flaps...should be finished by February perhaps.

                                    TwistedGrin

                                    Comment


                                    • WOW!
                                      Maiden plus three flights today 03-27-21

                                      The maiden was a breeze.....10-12mph headwinds with brief strong puffs of 15mph crosswinds. This airframe acted like nothing happened in the air. I was amazed that is simply lifted off the runway (Grass field) at about 25yards of run up. The rotation was nearly flat and once airborne....ya it was an arrow. Not real fast (counter rotating 3blade props) but very respectable pace. It is super stable and exhibited no vile traits. Turns, rolls, loops, figure eights were all done with ease. The landing was a bit awkward as the winds lifted it back up about 5ft, I had to blip the throttle and flatten it back out then merely landed again..no flare but a gentle flat three point landing.

                                      I was able to make three other spirited flights cruising at or near 50% throttle with shallow dive runway passes at full tilt. The sound of the props is really neat...the galley enjoyed the sound and the looks of this strange airframe. Flight duration on the 6s 100C 8000mAh LiPo was 6:00min landing at 3.80v per cell.

                                      The fourth flight I pancaked a little too hard on the rain soaked soft grass which popped the retract mounts in both wings.....the plywood retract mounts have split open and cracked the wings....but this will be an easy fix.

                                      The airframe flies on rails, has an excellent resonance sound from the props, looks wickedly odd in the air, tight axial rolls, huge gargantuan loops, tight figure eights all day....easy to land.

                                      If I prang this one up beyond repair - I will order another...it's that fun for me.

                                      Special Note: My build deviated from earlier post ...deployed off the shelf prop spinners and customized the nose gear. More information can be found at the other webthread for this model (https://www.rcgroups.com/forums/show...-Models/page35)

                                      Motors: Flight Line 5055 390Kv
                                      Props: MAS 16x10x3 Pull/Push props (Counter rotating)
                                      Spinners: Extreme Flight FW-190
                                      Nose Gear: Freewing A10 80mm nose gear (MotionRC FJ311110811) / Have to insert a longer spring stopper inside the strut cylinder - shorter travel, compressed spring
                                      Battery: RCJuice Hobby Star 6s 100c 8000mAh LiPo (901grams)
                                      Flight Battery: Spektrum LiFe 2s 6.6v mounted in front of the forward battery tray
                                      Lead weight: 105ounces mounted on the nose rear firewall and in front of the forward battery tray
                                      ESC: (2) Castle Talon 90
                                      Receiver: Spektrum AR8010
                                      Stabilizer: Hobby Eagle A3-L
                                      CG for flight: 163mm

                                      All good

                                      TwistedGrin
                                      Attached Files

                                      Comment


                                      • Congratulations! Always good to hear when things go well.

                                        Is the the nose weight correct? Seems like a lot with an 8000mah battery up front.

                                        Comment


                                        • Yep, CG at 163mm. I tried to make some "minimal" repairs to the wings main landing gear mounts....the 1st flight of the repair trials the right main gear would not deploy. I landed on the left main and the nose gear with a full run out without issue..... My nose gear is perfect and holding up just fine....I flew three more sorties with the mains down flying dirty. Still did all the requisite loops, rolls, figure eights without any problem....landing softly. I will set up the new set of wings and carry on. Open up the original wings for drastic repairs as needed.

                                          Love this bird

                                          TwistedGrin

                                          Comment

                                          Working...
                                          X