Rutan Quickie - Xplane/Oddball Challenge build.

[ratcheeroo]

So while the other landing gear tip drys I decided to start finishing the wing. I got the turtledeck part of the wing and the mounts squared away, just have to drop a couple of tubes in to guide the mounting screws to be able to secure the wing. Tomorrow night it will be the other canard tip and get the canard mounted in place and hopefully get servos in it and the wing

[peanut]

You have a gift! That is one clean looking build. I really like the removeable wing with the tongue depressor thingy? Those things are incorperated into at least half my builds either at the beginning (now) or after something failed.

[ratcheeroo]

Thanks my friend, yeah I love those things, very versatile, low weight, high strength.

[Burkeomatic]

Did someone say popsicles

[ratcheeroo]

LMAO!!!!

[ratcheeroo]

Slowly getting back into the swing of things here. Hatch is skinned as well as cockpit/canopy area. Canard is mounted in place, still have to mount the wing. Going to run some servos and call it a night.

[ratcheeroo]

Wing is mounted, canard mounted and tail wheel in. I'm not totally sold on my wingtip/wheel covers , hence the absence of one on the left wing. I think I will print a thinner wheel and try again. Sits pretty in spite of that LOL.

[Burkeomatic]

Looking good, it is going to be interesting to see how this thing flies.

[ratcheeroo]

Close to the end now, servos are in, finally decided on a power plant. Going to finish out the front end tonight as well as glue on the left wingtip. Dont have a plan for the canopy yet but do have a couple of options. Really liking the weight at 590 grams as I suspect I'm going to need something bigger than a 2250 4s to get this to balance on CG.

[ratcheeroo]

Working the pattern for the final skin, this piece will be foamboard so that I can round over the edges on the front of the cowl. Canopy tonight then make it look pretty LOL! Not sure where its going to fit in the hangar. I am a little unsure as to how to set up servos. Should it be set up like elevons or just as a normal 4 channel? I am leaning towards just a normal setup. Any thoughts?

[Burkeomatic]

Oct 20, 2022 9:18:33 GMT ratcheeroo said:

Working the pattern for the final skin, this piece will be foamboard so that I can round over the edges on the front of the cowl. Canopy tonight then make it look pretty LOL! Not sure where its going to fit in the hangar. I am a little unsure as to how to set up servos. Should it be set up like elevons or just as a normal 4 channel? I am leaning towards just a normal setup. Any thoughts?

It looks real nice, I would probably just set it up normal, I could see double elevons adding another layer of complexity. You would have to reverse the pitch on the fron ones, no?

Have you found your CG yet? If you haven't are you just going to glide test it? Or are you going to draw a diagram and calulate lift based on wing area and work out the statics problem?


Were you planning on doing front elevators and rear ailerons? Or vise versa?

[oliverw]

Oct 20, 2022 9:18:33 GMT ratcheeroo said:

Working the pattern for the final skin, this piece will be foamboard so that I can round over the edges on the front of the cowl. Canopy tonight then make it look pretty LOL! Not sure where its going to fit in the hangar. I am a little unsure as to how to set up servos. Should it be set up like elevons or just as a normal 4 channel? I am leaning towards just a normal setup. Any thoughts?

It is looking amazing, and definitely a normal 4 channel setup

[ratcheeroo]

yeah just setting up normal, front elevators and rear ailerons. I think I will just go with the CG point indicated on the balsa plans, has worked for me pretty well so far. I will probably use a CG calculator just to confirm.

[Burkeomatic]

Oct 20, 2022 15:28:59 GMT ratcheeroo said:

yeah just setting up normal, front elevators and rear ailerons. I think I will just go with the CG point indicated on the balsa plans, has worked for me pretty well so far. I will probably use a CG calculator just to confirm.

CG calculating will be fun with 2 centers of lift. I was thinking about doing something kind of arbitrary like this. 

Calculate CL of each wing. Then get the wing area of each. 

Say the front wing is 100cm2 and the rear is 150cm2. 

So then add them up, and the front wing is 100/250, and the rear is 150/250. So the front wing would be providing 40 percent of the lift, and the rear 60. 

So then if there is 20cm between the wings, the cg would be about 12cm back from the front wing and 8cm forward from the rear. 

It would be simple but it seems like it would work. I realize there are tons of outliers and variables that could happen, but be close. 

[ratcheeroo]

Oct 21, 2022 0:24:06 GMT Burkeomatic said:

Oct 20, 2022 15:28:59 GMT ratcheeroo said:

yeah just setting up normal, front elevators and rear ailerons. I think I will just go with the CG point indicated on the balsa plans, has worked for me pretty well so far. I will probably use a CG calculator just to confirm.

CG calculating will be fun with 2 centers of lift. I was thinking about doing something kind of arbitrary like this. 

Calculate CL of each wing. Then get the wing area of each. 

Say the front wing is 100cm2 and the rear is 150cm2. 

So then add them up, and the front wing is 100/250, and the rear is 150/250. So the front wing would be providing 40 percent of the lift, and the rear 60. 

So then if there is 20cm between the wings, the cg would be about 12cm back from the front wing and 8cm forward from the rear. 

It would be simple but it seems like it would work. I realize there are tons of outliers and variables that could happen, but be close. 

I think that would work, logic is solid. I think I read somewhere that the front wing provides 60% of the lift. I will try it and see how it compares, thanks.