IMAC Dalton 300 ml build thread.

[Bunky.F.Knuckle]

i am wondering if i should go with a 1.5 liter tank, that would make it less nose heavy. or, if i should fix the thrust?

CG. Push your CG back using your batteries about 1" at a time. Also too, when you get wheel panties on it, (should be a law against flying without them)it will add a bit more nose weight, therefore making it more nose heavy. So, you will need more tail weight. If you run out of battery lead, you could always stick , dare I say, dead weight in on the tailwheel block in the rear of the airplane. For every 3 ounces of nose weight, you will need ~1 oz in the tail to counteract.

Thrust line sounds like it may be right on? How is the up/down thrust on a vertical up line? If it is windy, I will orient the airplane to where I can see either up/down or left right orientation. I will do it both in the wind and in a down wind segments.

Incidence..... It gets a little touchy feely there...... You could give yourself 1 washer of down incidence (raise the LE of the stab) on your mounting tab, provided you went with the method shown on the plans. If you go this route, be prepared to retrim the elevators.

My D300 flys with 33oz of fuel on board with a 157/170 engine. I fly 9 min, and this is mixed 3d/precision flight. Once I get the engine tuned up better, I would expect lesser fuel consumption in the same amount of flight time. A smaller fuel tank will only shorten your flying time, I don't think it will change your CG that much.

 

[orthobird]

Congrats Ortho! Sounds like your months of hard work are really paying off.

One thought when reading your trimming/flight characteristics. Added 5 clicks up for level flight. Would that be impacting the downline tendency to pull out?


BJ Swope

i need to make a clarification here. the elevators are set up with a high servo resolution. what this means is that the net result is, high rates, travel set at 100%, the elevators deflect about 20 degrees or so.

if i used 5 clicks, it would be probably equal to 1 click on a 1:1 linkage geometry. mine is not 1:1.

my servo hole is the less than 1" hole, and the control horn is about 2" out from hinge line.

 

[orthobird]

Is it thrust or incidence that requires the up elev?

Doesn't the IMAC trimming bible, I cannot recall the author, provide tests to indicate which?


BJ Swope

the incidence was set to zero at the wings, and the incidence was set to 0 at the stabs.
immediately after take off, 1st thing i did was use the elvevator trim to make her fly level. once this was done, i then flew her inverted and climbed at 45 degrees.
when i placed the airplane inverted and did this, then i let go of the elevator, and ever so slightly did she arc towards the canopy. she is very very little of nose heavy.

i wanted to clarify this.

thank you all for the compliments. I am very very happy!

 

[orthobird]

Bunky, i will recheck the up line and down line again on Saturday. This test flight i did alone. On saturday, my pals will be there, and they will help me trim it. (i hope)!!
I actually like the cg where it is. but you are right, when i add the wheel pants (before the police come and get me), it will make it more nose heavy.

 

[Bunky.F.Knuckle]

If it pulls or pushes in a down line, that is incidence, not thrust line. Vise versa for uplines.

Also, come along at full throttle, straight level pass, kinda low, and chop the throttle rapidly, right in front of you. Note if it climbs or dives too.

 

[orthobird]

If it pulls or pushes in a down line, that is incidence, not thrust line. Vise versa for uplines.

Also, come along at full throttle, straight level pass, kinda low, and chop the throttle rapidly, right in front of you. Note if it climbs or dives too.

you were right. thrust is all good. did you test, and no climb or diving.

it is the incidence., reason being that i set the wings and stabs at zero. so in order for it to maintain level flight, i had to add few clicks up elevator. so when i do a downline, it pulls up. this was fixed with a throttle to elevator mix, that is only active when high idle is on. i guess ideally, i should increase the wing incidence to 0.5 +, then it would fix the problem. (i imagine)

 

[orthobird]

 

[orthobird]

i forgot to mention, wheel pants were on!!

 

[orthobird]

my buddy caught the maiden on video!! thank you Stacey!

 

[bigblueswope]

That thing presents so well! On your downwind and while turning to base, the yellow on the wing and the fuse made a very nice looking cross.




BJ Swope