R/C conversion of the 2.6" Estes V2 into a semi scale manned A4b

Discussion in 'Rocket Boosted Gliders' started by tab28682, Dec 17, 2014.

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  1. Dec 17, 2014 #1

    tab28682

    tab28682

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    I like to have several projects going at once for varity and thought I would share this one.

    I had one of the 2.6" semi scale V-2 kits around and decided to convert it into a semi scale R/C glide recovery manned A4b. Did most of the work so far one afternoon of the Thanksgiving holiday weekend.

    Will have about one ounce of radio added to the airframe. Control will be mixed pitch and roll via "tailerons". I test glided the model as a free flight to get a good CG position to plan the radio installation. With about 1/32" up trim on the tailerons, the model had a nice flat glide with no ballast needed for glide. CG control will be va the countered weighted boost tube that ejects, leaving the model at the correct.

    Servos and pushrod guides are installed. Still need to make the vac-formed or drape formed canopy pattern and canopy, secure RX and flight battery and install control horns. Will test fly with some clear finish on the balsa to see if it earns a paint job. I have always liked the interesting rendering drawing below and will use that color scheme when it gets painted.

    The counterweighted boost tube will be a little on the heavy side, but the model ought to do well launched with an E9 at 75-80 degrees of elevation. Will have to get a better idea of the final gross weight to see if D12 flights would be worth while.

    I have two weeks off for the holidays starting Friday and hope to test fly this, plus the new shuttle conversions and some other things as well during the break.

    image.jpg image.jpg
     
    Last edited: Dec 17, 2014
  2. Dec 17, 2014 #2

    Vaportrail

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    You wouldn't happen to have rocksim or open rocket file made for that you might share do you? Could PM it to me if you like.

    Looks fascinating. I really enjoy the projects folks go above and beyond on.

    Subscribed.
     
  3. Dec 17, 2014 #3

    samb

    samb

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    I'm sure Tom will answer your question before too long Vaportrail but I believe his favorite design tools are Mindsim and TonsofExperiencesim. I'm just a giggly fan-boy when he comes out to fly with the Dallas club. Neat stuff.
     
  4. Dec 17, 2014 #4

    burkefj

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    Nice Tom, will be interesting to see how it flies. It looks good so far!

    My 5" profile RC version with taileron only is an excellent flyer. I did remove the fin tab from the bottom fin just so it wouldn't catch anything on landing. My CG is a bit further forward than you will probably need due to your rounded fuse. I did a DML V-2 PMC to the A4B config a long time ago, but it was so heavy in plastic it wasn't a glide model, but flew great on D21's.....the cg on that was just ahead of the leading edge at the root and it flew dead straight.

    A4BwingedV2.jpg

    IMG_0078.jpg
     
    Last edited: Dec 17, 2014
  5. Dec 17, 2014 #5

    tab28682

    tab28682

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    Samb got it right....:) Not going to do a sim.

    I approach this type of model as a rocket powered aircraft and not as a winged rocket. I have a lot of experience building and designing RC models and rarely have any CG issues.

    A stable glide shows that the CG and CP are fairly happy. Balancing the model at around 22-25% of the wings mean aerodynamic cord will work. I typically boost a model like this with the boost CG a bit further forward than the glide CG.

    With the oversize Estes semi scale V2 fins, plus the extra fin area of the A4b mods, I am pretty confident it will fly well.

    The R/C glide recovery will be short, fast and fun! I might fly the A4b up on an RC model that has a piggyback rack that we use for carrying up RC sailplanes and do a drop test from a few hundred feet up before the first powered flight.
     
    Last edited: Dec 17, 2014
  6. Dec 17, 2014 #6

    Woody's Workshop

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    1 KOOL Rocket!!! rrrr r/c shooting thingy.
    Nice work indeed.
     
  7. Dec 18, 2014 #7

    TheTellurian

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    I just love rockets with wings or wings powered by rockets if you will. [see my avatar] I assume the green tape on the fins is the taileron hinge. I've an Air Hogs Titan bash with tailerons that uses nearly the whole stabilizer, seeing how much smaller this model's are can you report their effecency? Love to see the boost tube details when you get around to it.


    Thanks
    Richard
     
  8. Dec 18, 2014 #8

    Daddyisabar

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    Very Cool. The old Hostile Projectiles kit needed the CG about a third of the way down the wing from the leading edge root to prevent a powered loop the loop. That was a bit more scale though on a C6-3 and launched vertically. All silly, mind simmed, odd looking Nazi rockets required appropriate Axis steel helmets for assured safety. If you are asked how the real one flew just say it was probably sabotage.

    rockets V23 021.jpg rockets V23 023.jpg rockets V23 006.jpg rockets V23 002.jpg rockets V23 003.jpg V23 044.jpg V23 043.jpg V23 042.jpg V23 038.jpg V23 037.jpg
     
    Last edited: Dec 18, 2014
  9. Dec 18, 2014 #9

    tab28682

    tab28682

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    The green tape on the tailerons is temporary and gets replaced by CA type hinges before final finishing.

    Small tailerons will work well on this model, especially during high speed flight. Not going for aerobatics, just creating enough control for some boost corrections if needed and to establish a well controlled glide after ejection.
     
  10. Dec 18, 2014 #10

    burkefj

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    good lord, I thought I was the only one with the sickness...:) But I agree, helmets are required for waffen launching....

    IMG_0016.jpg

    IMG_0079.jpg
     
    Last edited: Dec 18, 2014
  11. Dec 18, 2014 #11

    Daddyisabar

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    The sickness is spreading. One of the guys at our club is starting on an ME 163 Komet build. Will need to dust off the old helmets when that one flies!
     
  12. Dec 18, 2014 #12

    tab28682

    tab28682

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    I do love Komets. I have an R/C Komet with a very small prop and electric motor in the nose with an 18mm motor mount bringing up the rear. Great fun with an air start while flying by under partial electric power. Thus flight was the first one on a C6. Plan on a D18 flight soon.

    http://m.youtube.com/watch?v=9NbLpHf0ZDA

    Local flying buddy Dave Schafer has a 4-5 foot span ARF RC Komet that does very nicely on I161 power:

    http://m.youtube.com/watch?v=-1_pQj9kM2Q
     
    Last edited: Dec 18, 2014
  13. Dec 18, 2014 #13

    burkefj

    burkefj

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    Man, we are on the same wavelength, my komet was 24mm, I had a bit of wing flex if I ran the electric motor during rocket boost so I had to be careful....also did a XF-92 thunderceptor with an electric pusher and above/below 18mm/24mm rocket motors that I could airstart as well, that was a hoot....had to run a zagi 5x5 prop to clear the motor exhaust.....it was marginal on that prop, I really needed a 6x4 but that quickly became a 5x4 if I lit the rocket motors:)
     
  14. Feb 9, 2015 #14

    tab28682

    tab28682

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    Had a great day at the RC field today!

    Among other flying, I flew two drop test non powered flights of the RC A4b today. I rigged up a cradle that mounts on the top of my big Carbon Z Carbon Cub that has a servo activated release for the A4b. Flew the two piggyback drop test flights from about 400-500 feet AGL.

    On board video of the release from the mothership and photos of the drop flight and landing coming shortly.

    Perfectly happy with the drop tests. The A4b has a decent and not insanely fast glide, although it does get to the ground fairly quickly....:) The taileron controls were just about right for this model. Need to rate down the roll control a bit with a little more expo near center. Pitch was just right.

    Carries about 1/16" up elevator trim for a good hands off glide, so it is just slightly nose heavy. Will do the first boost at that CG point and perhaps move the glide and boost CGT back a tad later. Will have a TX mix switch for a controls centered boost at position 1 and automatic glide trims set at position 2.

    Able to flare and land both flights in the grass right in front of me 70 feet out across our 40 foot wide paved runway.

    The A4b is now cleared for launch. If it survives the first launch, it will get an airbrush camo finish and some Luftwaffe markings.

    Looks like the boost weight is going to be pretty piggy at 14-14.5 oz. I am thinking it will need some E20-4 composite power to boost well close to vertical.

    Still need to finish up the pop pod and add forward ballast, shock cord and parachute. And need to modify my RG launcher with a position to fit this little guy.
     
    Last edited: Feb 9, 2015
  15. Feb 9, 2015 #15

    tab28682

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    Here is the sequence from one of the piggyback flights yesterday. Note that I followed Frank's advice and removed the protruding tab from the lower fin, for now:

    DSC_0140 ES.jpg DSC_0110 ES.jpg DSC_0116 ES.jpg DSC_0118 ES.jpg DSC_0120 ES.jpg DSC_0128 ES.jpg DSC_0130 ES.jpg DSC_0131 ES.jpg DSC_0132 ES.jpg DSC_0137 ES.jpg
     
  16. Feb 9, 2015 #16

    KidRockET

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    Very cool...
     
  17. Feb 9, 2015 #17

    burkefj

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    Very neat, happy it worked so well, what is your glide weight now? I think at 14 ounces with the pod an E-15 or E20 composite should do nicely. It's small so you don't want to get too high anyway.

    PS I got out last weekend and got some flights on my foam version, I don't want to take away from Tom's thread, but the second flight got a a neat shot coming out of the sun and these winged V-2's look so cool gliding by....https://www.youtube.com/watch?v=KL9M-1fJjzA&list=UUmToWCQ4okdIYb848HJn_sQ
     
    Last edited: Feb 9, 2015
  18. Feb 9, 2015 #18

    samb

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    Great photo sequence Tom. Looking forward to seeing it "decorated" with a woosh generator installed, sitting on the pad. :)
     
  19. Feb 9, 2015 #19

    Daddyisabar

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    That will be cool with a vertical take off, just like the real one. Getting the right motor might need some flight testing. Always nice to "pop up" an oddroc up (E 30), but the Hostile Projectiles one flew better on a C6 than a D 10. More power tended to exemplify its nasty, airplane like flight characteristics when you want your A4b rocket going perfectly straight up. Even a slight angle of attack on the boost and that big wing will want to take over. Transitioning from stable rocket to flyable glider by blowing out the extra nose weight in a pop pod will be cool.
     
  20. Feb 10, 2015 #20

    tab28682

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    Good points, but I have had a lot of flights where I was actively radio controlling the boost on some fairly exciting RC rocket and boost gliders. With the tailerons, I will be spanking that wing down if it tries to take over....;)

    As long as it is stable and balanced to fly, with the CG at launch in the same place or even faintly ahead and has good velocity off the launcher, I thnk any wind effects will be pretty easily manageable.

    I typically launch my free flight MiG-21 vertically, with the wing edge-on to the local wind. That typically prevents wind related disturbances until the model is moving fast enough that the wind is no longer an issue.
     
  21. Feb 10, 2015 #21

    WillMarchant

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    Very cool thread, thanks!!!
     
  22. Feb 10, 2015 #22

    TheTellurian

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    Nice pics!

    When you put wings on a rocket it needs to be balanced like an airplane with the CG ahead of the MAC of the wings. Rocket sims tend to put it too far back hence the nasty results when adding more weight to the rear i.e. D motor instead of a C. Learned that the hard way with my Orbit Jet [see avatar] It would be launched wings parallel to the wind flying straight till the wing rotated square to the breeze then the wing acted like a pivot or fulcrum weather coaking to the wind. Moving the CG forward of the MAC helped reduce this.

    Yah! Paint and video. :cool:


    Richard
     
  23. Feb 10, 2015 #23

    tab28682

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    Exactly. If it will fly, it will boost, because if the CG/CP is not correct, it will not glide correctly. The pictures prove that it flies, so not worried about the boost.

    Out of a fair number of winged boost glider original designs with rear engine mounts, I have never had one go into cruise missile mode or tumble out of control. All boosted well at or very near the very same CG it was test glided at.

    Being mostly an airplane guy, I approach these things as rocket powered aircraft and not as rockets with problematic wings with mysterious effects.

    Murphy will have to find another way to mess things up....;)
     
    Last edited: Feb 10, 2015
  24. Feb 10, 2015 #24

    TopRamen

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    Most impressive!!!:clap:
     
  25. Feb 11, 2015 #25

    TheTellurian

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    Hi Tom. I see you know what you're doing, the piggyback testing proves that. My comments were intended for the Hostile Projectiles issue so I hope I didn't rub the wrong way.


    Richard ;)
     
    Last edited: Feb 11, 2015
  26. Feb 11, 2015 #26

    burkefj

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    Tom, do you have any pictures showing the radio/servo installation and battery access? What is your glide weight?
     
  27. Feb 11, 2015 #27

    Daddyisabar

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    Flying Nazi Secret Wonder Weapons like this should not be that hard, nor is it real rocket science. It is just a matter of getting experience on a particular model. Just need a tad more stability margin for the rocket going up, blow out a bit of nose weight to make it glide better and easier to control. It might even work with a smaller margin given ideal launch conditions and set up. Who knows until you press the button. Just be ready in case it decides to go airplane quickly off the rod or rail. Or if it wants to loop the loop, that is always a real crowd pleaser. On the HP kit my first flight looped the loop, more nose weight solved the problem. After five or so good flights I got bored and stuck in a composite D and it went airplane about 30 feet off the rod. That was a long recovery walk, but all in the name of science I say. Then I beat it up over over the next five or so flights. After many repairs it must have got a bit out of align and started to fly like poo even in ideal conditions. It now sets on the shelf because I have lost my nerve and do not want to press my luck at the club when flying other Nazi Secret Wonder Weapons.
     
  28. Feb 11, 2015 #28

    tab28682

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    Glide weight is 6.75 oz before paint. Heavy, but wanted to use the stock parts and a medium duty tube inside the model to contain the booster unit.

    I will try to get some pics of the radio installation shortly. It was not all that elegant for now. The RX and battery and BEC were simply taped to the part of the inner body tube just ahead of the nose cone shoulder. The servos are each mounted in the through the wall wing root area where it touches the inner tube, just behind the CG. I cut two small hatches in the tube to get to the servos and recovered the lost tube strength with a balsa spar down the CL of the tube between the hatches.

    Lemon 6ch RX, small GWS ESC with BEC, 2s 240 lipo and two HXT500 servos.

    .032 wire in tube linkage to the tailerons, well supported for no flex.
     
  29. May 31, 2015 #29

    tab28682

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    The A4b model is just about ready to fly. Has not been a rush as every single launch since Feb except for one has been cancelled for wet field, no field or weather!

    Heading to a very rocket friendly RC airplane event next week (SMALL in Little Rock, AR) and hope to launch the A4b there the day before the event starts. Likely to be at least a couple of dozen rockets there.

    I was not going to paint it until it flew, but endless days of rain and wet fields prevented a launch locally, so I went ahead and gave it a quick pre-launch camo scheme from the popular V2 web site.

    Will have launch pics and hopefully a video next week!

    image.jpg image.jpg
     
  30. May 31, 2015 #30

    burkefj

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    Very nice!
     

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