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Thread: VAS Pegasus

  1. #21
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    That motor will handle a 7x6 sport prop on 4s. Pulls just shy of 50a. That's what I run on my Mini Drak.

  2. #22
    Quote Originally Posted by scotth72 View Post
    That motor will handle a 7x6 sport prop on 4s. Pulls just shy of 50a. That's what I run on my Mini Drak.
    I thought 6" seemed small too but take a look at this. Too conservative? http://innov8tivedesigns.com/images/...21-8_Specs.htm

  3. #23
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    Yes, the Cobra prop charts are conservative, unless you are full throttle the entire flight.

  4. #24
    Quote Originally Posted by scotth72 View Post
    Yes, the Cobra prop charts are conservative, unless you are full throttle the entire flight.
    I figured as much. Motors have designed capacities but they also have factors of safety. So you are operating beyond the designed spec and the motor can take it because it's got some fat in the specs, plus you are not wot for long periods of time.

    I'll start with the 6 and if it's too slow I know I can bump it up to a 7 thanks!

  5. #25
    Cold weather has totally stopped my pegasus build. I can only paint outside and I need 50 degrees (f) or higher to paint so I am stuck until I can get these parts painted. We are having the coldest temps in eastern NC in over 100 years. Anyway, everything is glued up and true. This is a nice looking model I am surprised it is not more popular. I have a feeling the other poster that pulled his canards had the elevators running normal instead of reversed and that's why he kept plowing into the ground. Anyway that's my hope because it looks like this will fly great. Can't wait to get it together.

  6. #26
    Got it painted and been steadily working on the build now.

    Couple of comments.

    I am not gluing the core into the fuse until the very last step. I can do this by splitting it into a top and bottom half, and pushing them in from the top and the bottom. This way I can locate the battery precisely to get the CG perfect. I don't see how you can do it earlier than last and have it be remotely accurate.

    It's not really worth painting these models unless you plan on using vinyl fill to smooth it out prior to painting. This is because the surface of the foam Alex uses is so rough that when you laminate a medium or dark color it looks terrible, covered with what looks like bubbles, but it's just recesses that can't stick to the laminate.. The only way to avoid it is to use bright colors only or totally smooth all surfaces prior to painting. This would be a tremendous amount of work and probably would add a decent amount of weight too.

    The method used to mount the motor is not great. Just gluing the plywood to the rear surface of the foam fuse has several problems. For one the foam is pretty flexible and once mounted you can easily move the motor around. This could result in some weird/bad harmonics during flight. Also since the foam does not form a good flat surface it's very easy to have a motor pointing off in an oblique direction. I will be adding wood fins buried into the back of the fuse straddling the existing wood mount. This should rigidize the mount quite a bit and make controlling the orientation of the mount surface easier, to make sure the motor is true to the frame (from the top down view).

    I've been paying close attention to making sure the wings and canards are parallel with each other (when viewed from the top and front or back. From the side they will have different AOA's), and square to the fuse. This is not easy as the parts are not rigid and depending on how you glue everything you can get some issues there. When I installed the canards I used the double sided tape method, but I staggered them port starboard top bottom. I did this to introduce a twist to the canard to make it parallel to the wing(again from top front and back views, not the side). If I installed the canard with tape evenly applied the fuse would have directed the canards to be out of true. I guess the cut holes for the wings and canards are not squared up when viewed from the front or rear. Foam wire cutting is not a precision operation.

    Anyway it's coming along well but I can see an inexperienced builder really making a mess of this kit. If you are building it you have to make sure the wings, canards, and fuse stay flat and true during the assembly process. It's very easy to end up with a plane that points in 5 different directions.
    Last edited by billyd; 25th January 2018 at 04:36 PM.

  7. #27
    Engineer for Jesus Christ IBCrazy's Avatar
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    BillyD - Yeah, the forum is dead. Facebook more or less took over.

    The plane can be twisted up really bad in the build and fly fine. I tested a few different configurations and all went well. A twist in the canard cannot overcome the main wing and thus it won't have any major adverse effects. The fuselage has a built-in 3 degrees of canard upward pitch to keep the nose up. DO NOT try to keep it level with the wings. The upward pitch ensures the canard stalls before the main wing to make stalls controllable.

    The big issue is torque roll on launch. The long body of the plane coupled with the moderate wingspan crates a torque moment about the central axis. It is best to not launch full power but instead throw hard at 1/2 power and then increase the throttle after it is out of your hands.
    If it is broken, fix it. if it isn't broken, I'll soon fix that.

    videoaerialsystems.com - Performance video piloting

  8. #28
    Quote Originally Posted by IBCrazy View Post
    BillyD - Yeah, the forum is dead. Facebook more or less took over.

    The plane can be twisted up really bad in the build and fly fine. I tested a few different configurations and all went well. A twist in the canard cannot overcome the main wing and thus it won't have any major adverse effects. The fuselage has a built-in 3 degrees of canard upward pitch to keep the nose up. DO NOT try to keep it level with the wings. The upward pitch ensures the canard stalls before the main wing to make stalls controllable.

    The big issue is torque roll on launch. The long body of the plane coupled with the moderate wingspan crates a torque moment about the central axis. It is best to not launch full power but instead throw hard at 1/2 power and then increase the throttle after it is out of your hands.
    No worries I have got it mostly together and it's perfect. Just warning that if you're not careful you can get a really out of whack looking plane. Just adding the last bit of electronics and I'll be ready to fly. It looks cool. I'll post some pics when I'm done.

    Sorry to hear about facebook taking over I won't use them so I guess I'll be left behind.

  9. #29
    Engineer for Jesus Christ IBCrazy's Avatar
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    FB groups taking over isn't bad as it clears out a lot of the noise and B.S. that used to happen on forums. The forums are going back to good old fashioned tech now.

    Remember this when it comes to the maiden flight: It is ok to stall the canard.

    In other words, be generous with the down-pitch of the canard. It won't hurt the plane to stall it. Just be ready to trim it out once the plane is in flight. I tend to prefer an off-power throw using a momentary switch as the motor cut off. The instant the plane leaves my hand, the motor starts up and the throttle is set at ~1/2 power. The plane tends to wobble out as I increase the throttle and then gets on step and rips out.

    -Alex
    If it is broken, fix it. if it isn't broken, I'll soon fix that.

    videoaerialsystems.com - Performance video piloting

  10. #30
    Quote Originally Posted by IBCrazy View Post
    FB groups taking over isn't bad as it clears out a lot of the noise and B.S. that used to happen on forums. The forums are going back to good old fashioned tech now.

    Remember this when it comes to the maiden flight: It is ok to stall the canard.

    In other words, be generous with the down-pitch of the canard. It won't hurt the plane to stall it. Just be ready to trim it out once the plane is in flight. I tend to prefer an off-power throw using a momentary switch as the motor cut off. The instant the plane leaves my hand, the motor starts up and the throttle is set at ~1/2 power. The plane tends to wobble out as I increase the throttle and then gets on step and rips out.

    -Alex
    Thanks for the advice I will set up my radio to do that. So set it up with alot of trimmed "down" elevator at the canard (meaning nose up) at launch and then back off in flight. Like a wing in that respect they typically need a fair amount of reflex to launch.

    Maybe I'll set it up for bungee launching I do that with the harder to launch planes, then I can keep both hands on the sticks (I have a foot pedal launcher).

    As far as FB clearing out the bs that's true, as long as the lack of traffic doesn't lead to the labs being shut down...

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