SIG Kadet Mark II
05-26-2005, 01:05 PM
#1
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SIG Kadet Mark II
Continued from [link=http://www.rcuniverse.com/forum/Which_4%2Dstroke_to_decide_on%3F/m_3009846/tm.htm]this[/link] thread in the beginners section:
I was thinking the same and tried to reduce the dihedral somewhat, but apparently not enough. the instructions says 4 inches from base to wingtip, mine is now about 3. both winghalfs is finished but not yet glued together. i want the dihedral to be around 1,5 to 2 (still to much?), should i just sand off the bottom beams?
the [link=http://www.sigmfg.com/cgi-bin/dpsmart.exe/DetailProduct.html?L+Sig+heqb5881+_Dimagefile_02SI GRC49_2ehtml_01]design[/link] shows an stabilizer with the elevator fin located behind the rudder. don't like it and are thinking of a straight solution, do you think flight characteristic would be influenced if i modify the fin forward in style with the rudder fin? in other words: i want the fins to end equally. bad english, but I guess you understand what i mean...
another thing: i'm wondering which tank go with for an saito 56, 8 or 10 oz? reason why i have to sort out this (engine and tank) now is because i need the right measurements for the firewall assembly for further advancement.
thanks.
Take about 2/3 of the dihedral out of the wing when you build it. This plane is an old design, and can be built and flown without ailerons especially with the amount of dihedral it has. I built mine with half the dihedral designed in the kit, and wish I had taken more out of it.
This plane has a fairly short tail moment, and will turn very quickly, and also has a sensitive elevator, but it is very stable and will fly fairly slowly if you want
another thing: i'm wondering which tank go with for an saito 56, 8 or 10 oz? reason why i have to sort out this (engine and tank) now is because i need the right measurements for the firewall assembly for further advancement.
thanks.
05-26-2005, 03:10 PM
#2
My Feedback: (1)
RE: SIG Kadet Mark II
Hi Hans, me again. If you had the dihedral at about 1-1/2 to 2 inches from base to tip, that would be about right, but don't sweat it. Taking the dihedral out just allows the plane to perform a bit better when you learn to do rolls and loops, the basic aerobatic stuff. It will decrease the plane's tendency to self-right from a bank and make it a bit less "stable" in the roll axis. Either way, it will be a great plane.
You could make the tail so that the rudder and elevator are"even", but you'll have to either make the elevator two piece, so they don't hit the rudder when you apply "up", or you could cut the bottom of the rudder at an angle great enough that it will allow the elevator full travel without hitting it. Either way, if you move something, I'd recommend moving the whole vertical tail/ rudder assembly back instead of moving the horizontal tail forward. Moving the rudder back will increase yaw moment slightly; if you moved the elevator forward, it will decrease pitch moment and make the plane much more sensitive to pitch commands. I mentioned in my other post that it is already on the sensitive side, because the fuse is not very long. Personally, I'd just go with the tail as it is designed. Changing dihedral is one thing, but moving the tail around can really play with overall stability, and the Kadet is a well-proven design. If you'll look at trainers in general, you'll see that most have a tail design where the elevator is aft of the rudder; it simplifies construction, since neither one will interfere with the other's movement.
As for fuel tank, I had a 10 ounce tank with the 2-stroke, and I was ready for a break before the plane was; it would fly quite a while on a tank, so the 8 ounce would probably be okay for the 4-stroke. I have a .56 Saito in another plane, and it is very economical. BTW, I'd recommend a 12-5 prop, but be sure and check ground clearance. You might have to use an 11 incher. I ran an 11-6 with the 2-stroke, but personally I think that's a bit small for the .56, so maybe a 11-8 would work. It will sure get you off the ground in a hurry.
Ken
You could make the tail so that the rudder and elevator are"even", but you'll have to either make the elevator two piece, so they don't hit the rudder when you apply "up", or you could cut the bottom of the rudder at an angle great enough that it will allow the elevator full travel without hitting it. Either way, if you move something, I'd recommend moving the whole vertical tail/ rudder assembly back instead of moving the horizontal tail forward. Moving the rudder back will increase yaw moment slightly; if you moved the elevator forward, it will decrease pitch moment and make the plane much more sensitive to pitch commands. I mentioned in my other post that it is already on the sensitive side, because the fuse is not very long. Personally, I'd just go with the tail as it is designed. Changing dihedral is one thing, but moving the tail around can really play with overall stability, and the Kadet is a well-proven design. If you'll look at trainers in general, you'll see that most have a tail design where the elevator is aft of the rudder; it simplifies construction, since neither one will interfere with the other's movement.
As for fuel tank, I had a 10 ounce tank with the 2-stroke, and I was ready for a break before the plane was; it would fly quite a while on a tank, so the 8 ounce would probably be okay for the 4-stroke. I have a .56 Saito in another plane, and it is very economical. BTW, I'd recommend a 12-5 prop, but be sure and check ground clearance. You might have to use an 11 incher. I ran an 11-6 with the 2-stroke, but personally I think that's a bit small for the .56, so maybe a 11-8 would work. It will sure get you off the ground in a hurry.
Ken
