harralk

My Feedback: (22)

I'm looking for a set of large scale Funtana plans, probably like 25-50%, if anyone knows where to find a set let me know. Otherwise I was thinking of getting other people's help on designing my own. I'm a drafter by trade and an engineering student and if I could get other people to help me out we could come up with a set of plans that I could give away for free. Either way, let me know.

Thanks

harralk

My Feedback: (22)

I was able to get a hold of a copy of CAD files for a 60 size Funtana. They'll need a bit of work, but I should be able to enlarge them. I was thinking of going with a 90" wingspan for the final plane.

Here's the wing detail that I'm starting with.

harralk

My Feedback: (22)

And the fuselage and formers. Does anyone know if I can take out that angle in the firewall and mount the engine perpendicular to the fuse centerline? I've always thought that was to help the plane knife-edge, am I wrong?

gr8taz nitro

My Feedback: (7)

I wouldn't take out the angle in the firewall. The angle is there for right thrust. The spinning propeller adds torque that pulls the plane in the direction of rotation, so the right thrust is to counter the torque so that the plane can fly in a straight manner.

krayzc-RCU

My Feedback: (31)

correct r-thrust = straight up lines

Tired Old Man

My Feedback: (1)

What direction does the propeller turn? After the answer think about propeller/engine torque again. Then consider P factor, which has a greater effect with the ascending blade. If it was me it would have a square firewall with adjustments made to a thrust line after flight testing.

Bob_S

Slip stream and P factor are probably the only ones we see where building in changes to the thrust line can help. Torque rolls the plane and gyroscopic precession only yaws when you pitch.

samtech

I wouldn't change the right thrust... If you did straiten it out you would only be able to trim in the plane at one speed and only at the RPM that you trimed it in at. At other speeds or low/high RPM the plane will yaw on it's own.
Is this your first build?

harralk

My Feedback: (22)

This is my first scratch build of this scale. I've mostly just built arfs and smaller kits, but I needed a project right now and this seemed like fun.

But now I remember p factor. Thanks for the refresher guys. Anyways, right now the thrust line has roughly 2 deg. vertical thrust, 4 deg. right thrust. That will probably need to be adjusted, but since as I understand p factor is also affected by the prop pitch and type of flying, I'm going to leave it as such for now and come back to it later if we need to.

samtech

Sounds good. Ok, 90" puts you on the tall side of 50cc. Is that what you want? Go for 100" 85cc.

harralk

My Feedback: (22)

I was trying to make this plane be sort of the design of anyone who actually wants to build it. I'm all for bigger though. Right now I'm working on the 3D model, haven't set anythig in stone yet.

harralk

My Feedback: (22)

Just finished scaling it up to a little over 100". Should have the 3D model done soon.

Actually it's closer to 115". Is that too big?

samtech

Yeah, that's big. 150cc Are you planning on doing lazer cut sheets for it too?

harralk

My Feedback: (22)

In order to keep this thing light and make sure everything will fit I'm thinking I'll have to get it laser cut. I'm just not sure where to get that done around here. Anyone know of an online source to do that sort of thing?

Ok, fixed the scale for the last time....100.4". And now I have to leave it 'cause I need to start making measurements.

samtech

100" good... Ok, if you talk to AK models their pretty good about lazer cutting. You might just give them a call to hash it out. They can give you advise on how to lay out your cut sheets and how much room to leave between the parts and so on. Very easy guys to deal with.

Bob_S

Give Bill Stevens a call in Colorado Springs. He owns Stevens Aero www.stevensaero.com and offers laser cutting services.

wind junkie

My Feedback: (1)

As an aside, isn't the full scale plane referred to as the "Katana?"

I thought the "Funtana" was the Horizon Hobby creation based on Sebastiano Silvestri's design. [sm=confused.gif]

Don't mean to derail your plans, but I"m curious since you posed this in the scale forum.

harralk

My Feedback: (22)

Yes, you're right. I was originally curious if Horizon made plans for a large Funtana.

Ok, latest update: I finished the 3D wireframe. Here's a couple pic's showing the (more or less) completed profile, both with and without the cowl.

This will be my last post in this thread. I'll be starting a new one for the rest of the design. Anyone who wants to contribute is more than welcome, and appreciated.

Thanks for all your help so far, hope to see you there.