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Grunder Industries ADF-01 Falken build log

#21
Well I have built the full size model, but the imperfections in the small prototype got bigger so it isn't very strong. I will make improvements to the plans and add more tabs and slots to make it go together easier. Other than that, the only big problem is that the cockpit isn't right, it just looks wrong :confused:. However, it shouldn't be too hard to fix, I will post pictures after I change the cockpit.
 
#24
The first full size version is finished :D!

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I am happy with the way it looks, other than a few tweaks that need to be made to make the pieces fit together better.

However, I am unsure of were to put the motor (as it is going to be a prop and slot jet) to get the best airflow.
I want to keep it as scale looking as possible so any suggestions about motor placement or building techniques would be very welcome.
 

Namactual

Well-known member
#27
The foamboard rendition looks great!(y)

As for power, a FT-mini power type set up with a pusher would work. Prop and slot could work too, but you are going to need either a very small prop or do a whole lot of cutting on your frame.

If it were me, I would go with 2 pushers. One on the rear of each nacelle. Make them RS2205's on 4s and see how long it would take to rip the wings off.

That sounds like way more fun.;)
 

Wildthing

Well-known member
#28
The first full size version is finished :D!

View attachment 126939 View attachment 126940 View attachment 126941 View attachment 126944

I am happy with the way it looks, other than a few tweaks that need to be made to make the pieces fit together better.

However, I am unsure of were to put the motor (as it is going to be a prop and slot jet) to get the best airflow.
I want to keep it as scale looking as possible so any suggestions about motor placement or building techniques would be very welcome.
That looks great, I really like it.

I would go as far forward as you can between the nacelles . Depending how wide it is in there for what size of prop there are some good little quad motors that get good thrust out of 5" and 6" props especially on 4S . The lighter the better for balancing purposes. I wouldn't worry to much about the engines, you will lose some speed but I think it will be ok. We did a YF23 and the CF44 with scale engines and got them both to fly really good.
 
#29
Thanks @Namactual and @Wildthing! I appreciate the suggestions.

If it were me, I would go with 2 pushers. One on the rear of each nacelle. Make them RS2205's on 4s and see how long it would take to rip the wings off.
I think avoiding the ground would be my biggest concern with that much power, but the wings probably would get ripped off too. :p
 
#30
Having worked on the plans and thought about this plane for the past week, I realized that the elevons are probably too close to the CG to have a good pitch effect. I am thinking they would probably act more like flaps when they go down and spoilerons when they go up. So I am going to start working on a hinge system for the canards so that they can control the pitch and the elevons will become just regular ailerons.
 
#31
I may have spoken too soon, as I was writing my last post I remembered the FT X-29 it has a similar configuration to the falken and in the video it flew great with elevons.

However I was reading a forum thread on the x-29, and I read this.

I only have two spare servos at the moment, so I don't really know what to do. Any suggestions?
 
#33
That was my first thought but on the thread about the x-29 the designer of the real X-29 said

[QUOTE Before somebody asks, I wouldn't suggest moving the canards with servos. Because of where the CG is located, the canard may stall if it is deflected leading edge up, and if it stalls, the nose of the model will drop even though a nose up command is being given. That is a VERY bad event and can lead to a crash.][/QUOTE]

The canards on the falken are in a very similar position to those on the X-29 so they might have the same problem.
 
#35
Yeah, I think I will build the falken with landing gear so that just in case there is funny business going on with the aerodynamics I won't lose the plane from a failed hand launch.
 
#36
After thinking about it I realized that I could adjust the endpoints on the elevator channel so that they have more throw than the ailerons, that way I can use regular elevons :).
 
#39
Falken update!

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1554245521001.png 1554245862898.png

I have redone the cockpit, and it looks much better now. Also I combined the powerpod receiver... thingy :unsure:, and the reinforcement tube for connecting the cockpit to the wing.

I ran out of black and white foamboard so I wasn't able to finish building this version. I am thinking that I will probably just paint this one red on top and black on the bottom, this scheme looks pretty cool, plus once I get it flying it will make keeping orientation much easier.

Should have more updates soon!