NEW 2017 HYDRO JET Official Thread

Discussion in 'Scratchbuilding!' started by RCPowers, Jan 29, 2017.

  1. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    Ok. Mine is done. Turns out, I did not have to worry about the extra bracing weight at all. My final weight WITH a 1300 3S battery is 15.3 oz. BUT, at that weight, with battery forward, I still need 15 gr (3 nickels) on the nose to balance. Which brings it to 15.8. I am going to add plastic folders to the bottom of the sponsons, so that will add a little more, but still way below the mentioned 18 oz limit.

    Observations - Wait to glue your cockpit on until you have your motor screwed into the mount, will make things easier for you.

    Maiden flight, not sure when. Its BEAUTIFUL today, but VERY windy. Tomorrow is another day in the 70's, but rain all day, then a return to our more wintery conditions, which has not been bad, but always windy. As soon as I catch a calm break I will maiden it. I will probably test it as a ground vehicle out front before i get a change to fly it at the field. I will grab video whenever I get out there.
     

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  2. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    Those that have dealt with foam block fuselages, how much weight does that add? Thinking a foam block cockpit might be a great candidate for this model if it adds some more weight up front. Never done one before though. So figured I would ask.
     
  3. bogusbandit56

    bogusbandit56 Top Gun

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    There are lots of different types of foam. I take it you mean blue or pink foam.
    I think the denser type of polystyrene like the sort used in packaging store bought planes would be pretty good but pink and blue are easier the sand. You could sand a nice shape in blue or pink and then hollow it out.
     
  4. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    This cockpit would need no hollowing (unless its too heavy), as the cockpit serves no storage function on this model. I am just thinking post build what could be done besides taping weights to the nose to take care of the weight issue. I dont know what a solid cockpit block would weigh, but I know it would would be more than the current one, but by how many grams, enough to satisfy the needed weight, or still not enough, or too much? Again, just thinking outloud here, not directly asking anyone these questions, unless of course, anyone knows.
     
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  5. XDmToter

    XDmToter Ace Pilot

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    Actually, their web site does say that they are for park flyers, but I have to agree with you. I wouldn't even use them on my NutBall.

    https://dubro.com/collections/control-horns/products/micro-razor-control-horn
     
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  6. I used the pink foam from Home Depot to create the boat hull shaped skis for the Lizard on Skis, sanded really nice.
     
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  7. bogusbandit56

    bogusbandit56 Top Gun

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    I will tell you what I am going to do. cut a rectangle somewhere in the cockpit area make a small ply box and make a watertight lid from foam then get some buckshot and put it in the box then glue it in the rectangle, balance the plane and stick the lid on. Or do it from underneath.
    No I`m not , I`m just going to stick some weights on the front. Who`s going to see them when they are 50 ft in the air or in the water.
    Different foams weigh different per cubic foot, so unless you know which foam you are going to use, no one can tell you.
     
    Last edited: Feb 24, 2017
  8. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    I truly hope this was sarcastic, and meant as humor, I did not see any emoticons, so.... I mean, are you really not asking me to discuss things about this model, in its own thread? Had to be sarcastic. This model, when complete, needs weight up front. A significant amount if you build light. My build is complete, and I have been thinking about the build. I know taping weights is simple and efficient. But I thought to my self, hey, some people carve fuse blocks, I wonder what kind of weight they bring. So I post asking those who know more than I, who may have done it. And you then ask me not to ask such things? It was just a thought on a possible mod that can have an advantage to using, needed weight. And I like to actually have conversation on a message forum. It seems to be lacking around here.
     
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  9. bogusbandit56

    bogusbandit56 Top Gun

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    Yes, I forgot the smiley face. As I said without the weight of the foam stated in in the manufacturer`s description it is impossible to say. It also depends on how much weight is on the tail.
    I need about 15,6 grams to balance mine out well, which would be about on the wing break or slightly behind it.
    I have hot wired and carved blue foam fuselages but it is still impossible to say what yours needs.
    Best bet to make a nice job is to carve the canopy and scoop some out then you can add some weight to it or scoop out to balance.
     
  10. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    Ok, I apologize for my quick reaction. yes, I know its impossible to know. I have just really never even held the foam that people use for blocks, so I have ZERO idea of their weight, other than its foam, so its light. In any case, I was just throwing an idea out there for others that have yet to build and like to modify. You could definitely get away with a solid foam block cockpit on this if you choose to do so, since further wight will be needed up front when the build is complete. Again, sorry for being too quick to assume and judge. For mine, I am just fine taping a few coins under there. I just want a clam day to let her loose. :)
     
  11. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    ok, my final post on my build other than video when it happens. Added plastic folders cutouts to the sponsons for heavy duty protection (also added ziptie pieces to the bottom end of the sponson rails, the other part of the bottom that will make contact with the ground), and black tape stripes on the bottom for orientation. With 2 nickels and a dime taped under the nose, my final weight with batter is 16.3 oz. Should be a perfect fly weight. I am about to return my batteries to storage charge though as a look at my weather app has 15 - 20 mph winds most of the week. Too windy for me.
     
    Last edited: Feb 26, 2017
  12. Flybyknight22

    Flybyknight22 Top Gun

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    This is a quick easy build.
    The Fuselage is very tight and really needs more room, If I build another I will enlarge it substantially or just use the extra 120% scale model that I had printed out at the print shop.

    Used these components:
    AUW is 18 oz
    All epoxy build
    Sandwiched 4 skinny tongue suppressors between the KFs and main wing plate in a triangle pattern similar to previous posted reinforcement pics with 5-min epoxy.
    2200KV Turnigy motor
    3-blade 6x4.5 prop
    40 amp Turnigy Plush ESC
    Control throws set to about 20 degrees
    Expo is 30%
    1350mah 3-cell 40c battery
    Plastic gear servos
    Clear plastic packing tape underneath the sponsons for skid protection.

    IMG_1321.JPG

    IMG_1325.JPG

    IMG_1322.JPG

    IMG_1328.JPG

    IMG_1329.JPG
     
    Last edited: Mar 3, 2017
  13. Flybyknight22

    Flybyknight22 Top Gun

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    Fz1,

    I built the first one at 100% scale and there isn't much room in the fuselage but also had the print shop do one at 120% for a later build.

    At 120% it looks like there is room for most any 3-cell battery and 7 inch props if one wanted to do that.

    I will play with the stock size Hydro-Jet for awhile and build the 120% scaled plane later.
     
  14. Flybyknight22

    Flybyknight22 Top Gun

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    Dang that sux!
    She sure was purty, sorry to see her crash.
     
  15. bogusbandit56

    bogusbandit56 Top Gun

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    I placed my battery on its side that way I was able to get the ESC alongside it to keep the weight forward. Probably not the best idea from a cooling point of view, but not a problem if you don`t go thrashing it around at full bore.
    I think the idea of the slim fuselage is to reduce drag in the prop wash.
     
  16. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    Beautiful job. Cant wait to see it in action. I was thinking of something similar as far as paint job when I still had it disassembled (Now I have NO creative talent, so my end result would not even have compared to yours ,lol), but before I knew it, I was gluing the thing together, and then went with my normal simple but effective tape stripes. :) But really, that is a sharp looking Hydrojet. Well done.

    I am wondering where your extra weight came from. Epoxy is not THAT much heavier than Foam-Tac right? I used foam-tac for all foam to foam gluing, but then sealed the needed areas with epoxy _+ microballoons. Oh wait, the paint right? Thats probably it.

    1 question. Did you need to tape extra weight to the nose?
     
  17. Flybyknight22

    Flybyknight22 Top Gun

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    BB56,

    Putting the two side by side sounds like a good idea, I might try that.

    I was even considering placing the ESC outside of the fuselage compartment to make for a little more room.

    Everything fits but is pretty crammed in there.
     
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  18. Flybyknight22

    Flybyknight22 Top Gun

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    BAF,
    Thanks,

    There probably isn't a lighter way to build than with Foam Tac. I use it for hinges only but I may do an all Foam Tac build some day.

    I used 30-minute epoxy for the KFs and 5-minute for everything else. That and the paint all adds weight.

    I also used extra reenforcement sandwiched in between the KFs and wing plate because of the inherent weakness in this area and that all begins to add up.

    I felt lucky to come in under 20 ounces to be honest.

    I generally don't focus too much on the weight of any build as long as it is within "reasonable" limits when finished.

    For beginners I don't recommend that and they should probably build as light as possible and follow all the recommendations from RCPowers.

    I bench test all the components on a Thrust Stand/amp/watt meter before installation and this gives a fair idea of what to expect in performance and reliability.

    I decide on a motor only after I weigh the build and let that dictate the thrust of the motor and prop I need to get it airborn.

    I don't generally like to use these Turnigy 2200kv motors because I have a tendency to build a little heavy and the motor doesn't generate the increased thrust I usually need but in this case it can handle 18 ounces especially with this 3-blade prop.

    A rock can fly given enough power, bumble bees and helicopters prove that, maybe this one will too. :)
     
  19. BadAxeFlyer

    BadAxeFlyer Ace Pilot

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    I do not either, and have not even weighed a lot of my other planes. The only reason I have talked about weight with this bird is because of Dave and Shannon's stated 18 oz limit before the prop will hit the water. So for that reason only, weight has been on my mind this build.

    My wondering about your extra weight was because I also used extra bracing in the cockpit area, and even with that I came in at under 16 [z, but as I was typing to you, I realized the paint, and the added epoxy can build up and that where it was. But yea, other than not wanting my prop to hit the water, I dont care about weight, as long as the plane flies true. :)
     
  20. Newt

    Newt Administrator

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    I did the same thing. Works great

    Sent from my HTC6535LVW using Tapatalk
     
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