Maidened the Knife Monday. Man I love this plane! I shouldda got one of these a long time ago. First flight with 30% flap mix on low rates it just barely would get it off the ground. I trimmed it out during a hairy first minute (it's my first fun-fly). Flew around a bit trying to become comfortable with the way it likes to float around nose-high. Landing was uneventful. With the model in the sun the ARF's color scheme isn't optimal! I need some more white on the wingtop. After a chill-out, I was ready for the second flight. Since it didn't want to lift off with 30% flap mix, I did it by the book with 50% flap mix. After a 4-foot roll I pulled back and - Wowzers - it leaped off the ground and took off straight up like a rocket! Here's the fun part - my first fun-fly and first 3D capable ship and I was hovering AND waterfalling AND harriering on the second flight! The Knife makes it SO EASY! I couldn't believe it. It felt like cheating. After too much fun and adreniline, I brought it in for a 5 mph greaser 3-point landing so easy and smooth it was too cool.

Gotta love the Knife!

Now for a photo and an application to the Profile Brotherhood...

Did I mention that I had never done a hover, waterfall, or harrier prior to the Knife flight? Previous planes: Avistar, Aresti.

Dont take much to get hooked into profile'n huh bgi?.....<GRIN>...Gator

Did you build it from a kit or plans?

Gator - do you like the knife better than the SuDoKhoi for 3d? Do you have plans for a knife?

Reply...no plans here...my dad built the one I'm covering so the plans are in the "MOTHERLAND" (Fl). If I had to choose now between the Knife and a Sud ...I choose the G Wiz B.....G

You like it that much??? the GeeWizBee over the knive and the SuDoKhoi?? You got plans for that one still?

Why do people keep saying this? The Knife is very capable of 10 feet takeoff's with NO flaperon mixing at all... I rarely used the flaperons on takeoff unless I wanted a 3 foot takeoff and even then they weren't near 50%. About the only thing I used flaperons on were waterfalls and harriers...

What engine are you using?

paul, I got plans for a Gwizbee.
I think the reason these ARF knifes dont want to take off is cause the ARFs got short gear. Get some crazy legs or steal some knife gear out of a kit and that will decrease you T/O distance......
I used my ARF knife gear on a Pro Twister. It was wider than reg P.T. gear and about the same height. I squeezed the gear together to make it taller and my P.T. will take off rather quickly...G

I used the Dubro composite gear...

Man I used some of the dubro's on a P.t. onetime. I never fly it but the person I sold it to told me they spread out to much on T/O and landing. Maybe its the way I had them on there, Does dubro make more than one kind of gear like that?...G

black = bad
white = good.....

YMMV

Pug

I had the white set and they were excellent. They will spring a little bit but only if you slam it into the ground....

OK I did have the black set...G

Paul, I think I have an set of plans for an Knife, also I have an nib kit for an geebee, if you would like to get the plans copied I'll bring them down next time I come down that way.

I have the plans and a set of wing ribs I'd be willing to sell...

Paul,

This is the ARF. If I replace this with another Knife, I'll probably get the kit. It would be much easier to get the servos installed with a kit. Now that I've built the ARF once, I "get it", but installing the servo rails to be removable while lining the servos up with the covers was a major PITA! A Kit will give me a chance to use a more visible scheme, as well. The ARF isn't bad, but if the sun is in your face, it can be tough to tell up from down.

Gator,

You said it! I'm building a couple scale planes, a 4-star 60, and a big Edge. But I'm a profile fun-fly maniac now!


David,

About the Knife lift-off problems:

I was using low rates per the manual.
Engine: TT .46 Pro with standard muffler
Prop: APC 12.25x3.75 fun fly
Fuel: 10/18 synthetic with 2% castor added (really 10/20)
95 degrees (hot)
The engine has about 2 tanks through it and so wasn't quite leaned out.

This engine/prop combo will climb out of a hover.

I did a 10 or 20 foot roll before trying to lift up. I gave it FULL UP with 30% flap mix and it barely lifted off. It was pretty anemic about it. With that prop, it accelerates very quickly!

After that flight, one of our best pilots explained to me that it wouldn't lift off without flap mix unless I bent the landing gear in to raise the nose. He ran one down a 300 foot asphault runway (no flap mix) and it would NOT take off! Other folks in our club who fly Su-do-khois have the LG pressed in so that the wheels are barely separated. Perhaps they didn't mix flaps in, either?

Obviously your experience is different. What's the trick? Is your tail wheel holding your plane's tail up as high as mine is? When mine sits on the LG, it has a shallow AOA. Tell me about your take-offs. What's the AOA with it sitting on the ground?

Just for referance, My krazy legs (the heavy duty) give me a lot of ground clearance..

this a 14" prop on my top cap arf. I am flying it with a YS 63

Here is is w/ a brand new set of Dubro blacks.

Needsless to say. the dubro blacks stayed on te airplane 1 flight.

As for the Krazy legs, I have beat them todeath and they keep coming back for more.

Ya those black one's look like crap!

I have Sledge 540 CF gear (blue) on my Knife (thanks T-28). Works great so far.

Karl

Now that I've showered my new toy with praises, I'm trying to solve a fuel draw problem. If you scroll back a little, you will see a photo I posted of the Knife sitting in front of my Aresti and Avistar. Note that the TT .46 Pro is all the way forward on the rails. Also note that there is no fuel tank visible (it's in the wing!) Because of this, the engine has a long way to draw fuel.

Since taking that photo, I've attached a Macs muffler (the small semi-tuned pipe). I've become better at hovering, but the engine doesn't like the pipe and the long fuel draw. It has a problem leaning out during a hover. To solve this, I put a 4oz header tank between the engine and the wing. While I'm not convinced this is the real answer because I believe that the fuel is still ultimately coming from the wing tank, folks tell me this will solve the problem.

This introduced a new problem - the header tank foams badly even though it has a nice layer of foam surrounding it.

So, what's the expert concensus:

1) Use more foam on the header tank?

2) Ditch the wing tank and use an 8-10 oz external tank (with enough foam, of course!)?

Inquiring minds want to know! Gotta solve my fuel draw problem!

Thanks

-brad

Well I've seen the same problem in the past and a header tank didn't solve the problem. If I were you I'd add a 6oz tank to the fuse opposite the engine and use that tank.

I've had really good luck with external tanks oposite the engine. All I use is a 6 to 8 oz tank with hooks screwed into the fuse, then just rubber band it on. Plus now you have a built in fuel gauge.

Check out how I did my SuDoKhoi:

Way cool. Thanks. Will setup like this and see how she hangs in a hover. Looks like an Irvine. Nice red.

Does the tank on the outside significantly affect knife edge?

I have owned pretty much everything Morris made except the twin and the bigger stuff as of late. He designed a very good plane, but still do not overlook the Sig Fazer. If set-up correctly the planes will do things not even in the book yet. I run either a Rossi or Heli 46 in mine again. I took my other 46 heli motor out and put it in my Ergo 46, but my new engine just arrived today OS 50 heli. Pretty much same case as the 46 and with right supports for the tailfeather flutter is not an issue. I used baking soda and thin CA to adhere thick gauge wire in all areas of the tailfeathers, it doesn't use the wire system like the Morris kits. But actually I like both systems. Morris build some good ones, and the Fazer has good lines as well. It would hover easily with the 46 with just a touch offset with engine torque. The OS 32 heli is a screamer too with a header & tuned pipe as well. This is my 6 th Fazer. The only one that was crashed was when I tried to go between two trees at a new field I got one wingtip busted slightly. I shortened each wing by 1" and the plane flew just as good as before just a lil more touchier landing was all. Morris & Sig makes great planes. I want to try the CG 330 next profile. Gotta love those Profile FF's..