I have a cap which is stable in an inverted harrier but right side up I cant keep is level.

that's because, dihedral or not, the plane is stalled and the wing root is lower than the cg, so it is topheavy and wants to flip. that's why i preffer edges and extras and such becuase they dont have that problem

I had one of these and it was stable in harrier. Do you have your C.G. near the rear of the recommended range? I used an o.s 1.60, and the plane was very light with this engine. If you are getting a lot of wing rock one of 3 things could be the problem.

1. The plane is too nose heavy.
or
2. The plane is too heavy for the amount of wing area (wing loading too high). This shouldn't be a problem unless you are adding weight or your engine is very heavy.
or
3. You don't have enough throw on high rate elevator.

There is a range of elevator throw (generally between 20 and 30 degrees) where the plane gets squirrly, but after you pass this range and get into the 35 to 45 degree range, the plane will want to lock into a harrier. A small amount of wing rock is normal but
this can be countered by aileron.

Greg

a cap can harrier very well its the set-up like Columbo
mentioned work that out and it will be very stable is your tank on the CG?

The CG is on the aft limit. I can roll inverted and it will fly hands off, so it seems to be about right. I have a saito 1.80 in it now and I cant tell you how much it ways but it feels very light. Most people who pick it up are suprised.

I will check the elevator throw and make sure its past that squirly range.
I may play with the CG a little but its already pretty pitch sensitive.

The thing that gets me is why it is so stable inverted. I guess the reply on CG makes sense. If I mounted some gear on the canopy I could land it pretty easy out of a harrier inverted. Im an airline pilot and have a 4 day sequence starting today so I wont be able to play with it until wed or thr. Ive heard the sig cap is way harder to fly in 3D than any of the other models. I would like to get my hands on an Edge to see the diff.

okay now it may be time for some spoilers to help out[8D]

Sounds like your c.g. and weight should be o.k.. Again check to make sure you have enough throw on high rate elevator. Also, I forgot to mention. Use a prop with the max diameter you can for your engine. The pitch should be no higher than about 6. This way you can get more airflow over the control surfaces to help stabilize the plane. This plane was very stable in harrier to the extent that I often harrier landed.

Greg

Most planes are more stable in inverted harrier than upright so that is normal.

Greg

Ok Im off to the LHS tomorrow for a new prop. I will check the throws as well.

Ive noticed in some pictures people are using elev-ail mixing, some having them going up and some down like flaperons.


Norman?, Norman, Hey isnt that were the sever storm center is? I saw some of those P3 hurricane planes up there a LONG time ago.

Funny you should mention the severe storm center, but you are right. It is now called the storm prediction center or (SPC). I am a meteorologist there. Our primary responsibility is to issue severe thunderstorm and tornado watches for the continental U.S.. The hurricane planes you mentioned are part of the National hurricane center. They are based in Miami Florida. They deal with the hurricanes. We deal with tornadoes. Are you a storm fan? There are a lot of storm chasers around here.

Greg

Well Im an airline pilot now so yeah I have a lot of respect for the south central weather. I spend a lot of time in that area flying out of DFW. Ive also been lucky (unlucky) to see 4 tornadoes, all from the ground. I saw the two P3's up there 12-13yrs ago when I was passing through that area. I seem to run across them ever now and then.

Speaking of storms and RC didnt some college met dept. try to send an RC plane into a tornado. Maybe I'll donate my CAP

They used to have an instrument called TOTO. But it was ground based. They would put it in the path of the tornado to get measurments. We have a few guys at our field who are experimenting with using RC planes to take upper air measurements. They
send the plane up on a balloon. The plane is then released and on the way down it takes measurements and uses a GPS system
to fly itself back to the pilot.

The sig cap that you have...I would rate it as a 6 on a scale of 1 to 10 as far as its ease of performing 3D. If you ever come across one
the Hanger 9 27% or 80" cap with the alitalia scheme is a much better 3D plane. It is even more stable in upright harrier than the sig one. No wing rock whatsoever. It is easier to torque roll and performs many other 3D maneuvers as well as a 35% plane. Problem is H9 stopped producing them because of poor sales due to the 80" wing span. I would rate this plane an 8 or 9 out of 10.

Greg