Help! rc pancake wing pre-design questions

[badpilot27]

so i might build something similar to a Vought v173 as a stol plane and im unsure what motor prop combo I should use.

I'm going to use 2 motors, run it on a 2200mah 3s battery and try to use large props to maximize the amount of prop wash over the wing.

I'm also unsure if I should use a cambered or symmetrical airfoil. I think a cambered airfoil will improve stol performance, but the real v173 used a symmetrical airfoil

 

[Flying Monkey fab]

I'd just use a Kfm-6 wing as it is very easy to make from foam board and give pretty good performance in this size range. So I guess my answer is symmetrical as that is what the Kfm-6 is.

I like this sort of experiment so please post what you come up with.

 

[bisco]

i love it vought_v173_flying_pancake_testbed_first_flown_in

 

[LitterBug]

It's kinda like building a flattened out Nutball... differential thrust for yaw control....

 

[badpilot27]

alright i just ordered the motors, escs, and props for it

i got 2 a2208 1100kv motors, 1045 propellers, and 2 30a escs

again its gonna be run a single 2200mah 3s lipo

does that seem good?

 

[LitterBug]

alright i just ordered the motors, escs, and props for it

i got 2 a2208 1100kv motors, 1045 propellers, and 2 30a escs

again its gonna be run a single 2200mah 3s lipo

does that seem good?

Very Plausible. I used to have a quad with 4 of those motors and the same battery. Plane will be much easier on the pack.

 

[badpilot27]

@Mr Man any idea on what's going on here?

 

[Mr Man]

IDK, what kind of loft is this? (There are several modes in the loft tool)

 

[Mr Man]

It may be that it can’t figure out how to make it with those guides. Maybe just do several lofts to get the right shape. (That’s what I normally do)

 

[Houndpup Rc]

@Mr Man any idea on what's going on here? View attachment 255091

I watched a video recently and the guy said that with the Onshape loft, you can't loft from a profile that is stacked inside another one in the same sketch...Maybe gets a few more pics so we can see what's going on better👍

 

[Houndpup Rc]

It may be that it can’t figure out how to make it with those guides. Maybe just do several lofts to get the right shape. (That’s what I normally do)

The guides also have to be constrained to the point on the sketch otherwise it won't work👍

 

[Piotrsko]

It's a KFM wing profile, just a bunch of flat sheets glued together in various widths top and bottom, center aft being the longest. No lofting, no tapers, easey peasey, just basic math. Like 30% times max chord

 

[Mr Man]

It's a KFM wing profile, just a bunch of flat sheets glued together in various widths top and bottom, center aft being the longest. No lofting, no tapers, easey peasey, just basic math. Like 30% times max chord

Huh?

 

[Piotrsko]

Kfm style wing is built up using stepped sheets of foamboard no taper, no sanding, SOMEWHAT blunt LE (45 degrees on a table saw). Supposedly builds vortices at step ends that negate drag. A Kfm 3 is 3 layers thick at the LE, a KFM 6 would be 3 layers up, 3 layers down. There used to be an airfoil thing here but Google is your friend. Incredibly easy airfoil to make, just glue sheets together, shape LE on table saw. Figuring out step widths is the hardest part, but is totally non critical. Wing it makes is almost indestructible. DON'T make me take a picture of my flying wing and post it..

 

[Mr Man]

Kfm style wing is built up using stepped sheets of foamboard no taper, no sanding, SOMEWHAT blunt LE (45 degrees on a table saw). Supposedly builds vortices at step ends that negate drag. A Kfm 3 is 3 layers thick at the LE, a KFM 6 would be 3 layers up, 3 layers down. There used to be an airfoil thing here but Google is your friend. Incredibly easy airfoil to make, just glue sheets together, shape LE on table saw. Figuring out step widths is the hardest part, but is totally non critical. Wing it makes is almost indestructible. DON'T make me take a picture of my flying wing and post it..

I don't think that's what he's going for, i think he's trying to make a more realistic model. I think, 👍👍

 

[Piotrsko]

Would be simple, build it then cut a huge circle, done.

 

[tomlogan1]

Sponz, somewhere, mentioned he had a friend who built a similar plane and if I am not mistaken, Sponz provided a level of assistance. Might have been in the 3d printed area.

 

[Mr Man]

Sponz, somewhere, mentioned he had a friend who built a similar plane and if I am not mistaken, Sponz provided a level of assistance. Might have been in the 3d printed area.

Yup, @localfiend designed it….

 

[badpilot27]

Kfm style wing is built up using stepped sheets of foamboard no taper, no sanding, SOMEWHAT blunt LE (45 degrees on a table saw). Supposedly builds vortices at step ends that negate drag. A Kfm 3 is 3 layers thick at the LE, a KFM 6 would be 3 layers up, 3 layers down. There used to be an airfoil thing here but Google is your friend. Incredibly easy airfoil to make, just glue sheets together, shape LE on table saw. Figuring out step widths is the hardest part, but is totally non critical. Wing it makes is almost indestructible. DON'T make me take a picture of my flying wing and post it..

would a kfm airfoil be better at keeping flow attached to the upper wing surface than a clarck y type of airfoil?

 

[Mr Man]

A Clark y would definitely be better