The Chipmonk Flew!

[Brian Massey]

Well the weather co-operated enough to get in a couple of flights with the new Chipmonk. Yes, it does fly, and yes it needs some trimming.

1; First of all, it wants to turn in on the take off roll; once it's airborne, it's fine. On the first launce it was "noticible", but on the second I had to back peddle a few. It could just be me. I haven't flown a plane with a swept leading edge in many many years, so maybe I wasn't lining up right. When I put the plane on my patio and roll it, it rolls to the right, away from the pilot; which is what I aligned the gear to cause. BTW, power is a B40 swinging an 11/6 two blade prop.

2/ In the air, the plane flys with it's outboard wing down (I built the wing per the plans with the inboard wing 3/4" longer). I'm hoping this can be corrected with a flap adjustment. (I eyeballed as best I could during construction and I really think they are true to each other.) I'm going to tweak the flaps a tad to "push" the inboard wing down, and the outboard wing up . . . unless someone has a better idea/solution. I had 1/2oz tip weight for the first flight, and took it out for the second; didn't seem to make any difference.

3/ The needle started to wander on it's own, and the wind was starting to kick up, so I'll pull the engine and clean/tighten the nva here at home before launching again . . . hopefully on Sunday.

I think the B40 will pull the Chip just fine.

Any thoughts/suggestions are welcome!

Brian

[Clancy Arnold]

Brian
First question How did it fly inverted?  Outboard wing high or low?

Before you tweak the flaps you need to determine how the plane is flying both upright and inverted.

Read the posts on the thread about Matt Colan's new plane.  They have posted information on how to trim a stunter correctly there.
Clancy

[Brian Massey]

Thanks Clancy;

Due to gusting and whirling winds I choose not to go inverted fearing that if the wing went high, it might get caught and cause a devastating consequences. I was also concerned with the shifting needle setting issue so I'm not in a position to answer the question. I'll be flying again Sunday, hopefully then.

Thanks,

Brian

[TDM]

First of all if the outboard wing is down you need to tweak the outboard flaps down in order to bring that wing up.
Also outboard wing down means outboard wing up when inverted and that is a recipe for disaster. Play safe until during the normal flight you get the wings as level as possible then if anything you will be safe inverted.

Make sure that the motor runs right before you go inverted. Also before you go inverted a tank that is a bit higher than the centerline of the NVA is safe since it ill give you a faster run inverted witch is the conservative approach. You should also notice a bit faster motor run on the ground if you pick the plane up and flip it inverted. If the motor run a bit faster inverted you are in good shape (safe). Later it can be trimmed out.

[Steve Helmick]

When getting lined up for takeoff, sighting down the flap hingeline is a good trick, since most designs have a straight hingeline. If yours doesn't, then sight down the elevator hingeline, or whatever is straight. The guy launching can easily sight down the TE, but if he doesn't, you should suggest it. If not, then sidestep a bit out of the "pilot's circle" to get lined up to the model. Not a good idea for official flights...I don't like to take a step until I absolutely have to. Anybody have a hand signal to give the launcher the idea to yaw the model before release? Be polite...  

The tailwheel is off the ground instantly, so I don't think the tailwheel alignment influences takeoff...but certainly does for the landing rollout. I would suggest making the outboard wheel a bit less free rolling than the inboard wheel, but wheel alignment is IMPORTANT. That said, my Skylark has a Bolly CF LG, and the outboard wheel is "toed in", but the inboard wheel is straight. I wasn't too happy about this, didn't see a good way to fix it, but the draggy outboard wheel worked fine. Some guys use o-rings for friction, and adjust it with wheel collars or axle nut tweeks. I just drilled the hole in the wheel out smaller for the outboard side. Both sides have a brass tube for a fixed sleeve that the nylon wheel spins on. You could probably come up with some sort of adjustable brake for the outboard wheel, maybe with R/C parts.    Steve

[john e. holliday]

When you set he plane on the circle to start the engine or after you have started the engine inverted, the plane should be lined up with the circle.  I the holder/stooge moves the plane and then does not line it up again, he/she will not launch for me until given a talking to.  I am not ashamed to move to line up with the plane if the holder/stooge does not see it's not lined up.  Bu, then immediately head for the circle during take off.

[Brian Massey]

I haven't been able to fly for a week now, too much dang wind. I have tweeked the flaps so the outboard flap is now offset by about 1/8th inch from the inboard; I'm hoping that will straighten the plane out a bit. I also found a problem with the needle valve. I took it out to clean and make sure there was not foriegn matter, but found instead that there was a problem with the threads. Some times when I put the needle in, it would wind down all the way; sometimes only about 3/4 the way until it stopped. I swapped out that NVA from another B40 still in the box. I also ordred 2 NVA's from Randy.

I put the plane on my patio and rolled it; it rolled slightly to the right, away from the pilot. Based on that I when I reinstalled the engine I forced it to point away from the pilot before tightening it up. When we get some decent flying weather, I'll find out.

At this point it doesn't seem like I'm going to get a whole lot of practice with the plane before the Northwest Regional.

Brian