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Bush Tandem!

Monte.C

Well-known member
#1
Inspired by the Rutan Quickie. Many thanks to @slowjo for naming this crazy thing (Bush Quickie ---> Bush Tandem).
I can't see any way to belly land this so it has to get wheels, and the best I can get to is some hard gravelly sand surrounded by rough grass, so they'll have to be big wheels. Big honkin' wheels on a plane that looks like some sort of sci-fi racer are entirely incongruous. It's almost like a joke!

Early design development:
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Ready to template:
Screenshot 2020-09-11 123615.png


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This build is turning out to be a surprisingly "standard" FT build. Definitely had to take some care with the wings, but after that it's just a box fuse. Both wings will be glued in place and there's loads of room for a great big hatch on top.

I figured I'd put the elevator on the front wing like on a canard, but today I realized you want the elevator as far away from the CG as you can in the front/back direction, so they'll go on the rear wing. Ailerons are most effective as far from the center axis as possible. Duh. I have a sneaking suspicion the optimal solution would be to mix all four control surfaces together, but I don't need that level of complication right now!

Not looking forward to building landing gear, but I do have a plan.

It's almost ready to start looking like something:
IMG_1017.JPG IMG_1023.JPG IMG_1037.JPG IMG_1054.JPG IMG_1064.JPG IMG_1066.JPG

I don't like burying servos - I'd like to be able to remove them when it's time to retire the plane - without destroying the plane - so I cut those notches in the bottom plate. I let in a piece of bamboo into the foam for strength, a BBQ skewer split in half. With a good knock I might still get a minor crease in the foam, but it won't break.

It'll be so much easier to paint the wings before glueing them in place, so I've got to shift gears to painting now.
 

Pieliker96

Well-known member
#2
I'll be interested to see what you come up with for the gear- the Quickie was notorious for its poor ground handling due to the ridiculously wide-stanced mains.
 

Monte.C

Well-known member
#10
Welcome to Monte's paint shop. How do you spell "frustration"? No matter what I do, the good detailing tape brings up some paint with it. It might be time to switch to simple line graphics. But it's such a crippling concept to not be able to do curves when I can do curves. :(

Stick to my plane painter's mantra, "It'll look good in the air. It'll look good in the air."

IMG_1098.JPG
 

Monte.C

Well-known member
#17
It’s looking good! What control surfaced had you planned?
Thanks man. If I understand your question, I was going to put elevators on the front wing (like on a canard) and ailerons at the rear, but then I figured out the elevators will be more effective on the rear wing. That position is farther from the CG.

And a rudder because I don't see any reason why a rudder wouldn't be useful on this plane, and because I need to put a rudder on every one of my planes until I master how to use the rudder to best advantage. ;) All I seem to do is bank & yank...
 

synjin

Well-known member
#18
Thanks man. If I understand your question, I was going to put elevators on the front wing (like on a canard) and ailerons at the rear, but then I figured out the elevators will be more effective on the rear wing. That position is farther from the CG.

And a rudder because I don't see any reason why a rudder wouldn't be useful on this plane, and because I need to put a rudder on every one of my planes until I master how to use the rudder to best advantage. ;) All I seem to do is bank & yank...
Had you considered elevons on the rear wings?
 

Monte.C

Well-known member
#19
Had you considered elevons on the rear wings?
Hey you know I hadn't thought of that. It would save 10+ grams, and some drag too. Would control be as effective as separate elevators & ailerons?

I do have to say I'm a little hesitant to try too many unknowns on a maiden flight. This model looks different than any aircraft I've ever seen.
 

synjin

Well-known member
#20
Hey you know I hadn't thought of that. It would save 10+ grams, and some drag too. Would control be as effective as separate elevators & ailerons?

I do have to say I'm a little hesitant to try too many unknowns on a maiden flight. This model looks different than any aircraft I've ever seen.
On the DL tandems I used elevons, and the DL-57 adds ailerons on the front wings (makes rolls really snappy). On the other hand, I don't have rudders on any of those as something I read about the Lysander said rudders were less effective than spoilers...and I'm not ready to try to put spoilers on the vertical stabilizers of a tandem...yet. I think from what I've seen with my designs to date is that the elevons need to be bigger than I'd make just an elevator, but I haven't tested that yet. I suspect the rudder will be beneficial. Adding yaw control will help keep it lined up for landing.

I wonder if the wing positions front and back, upper to lower, will have any effect on what control surfaces you put where. Your canard looks to be about 80% of the wings, so I wonder how the anhedral of the canard will balance against the dihedral of the wing stability wise?

That's what I love about scratch building, seeing if the design works out and takes flight!