Comp-Arf Extra 300L 2.12M

[catman3070]

If anyone is considering using washers behind the standoff, I wouldn't recomend this. If you notice before tightening fully that the stadoffs don't sit flush. This is what causes the ears to break of the engines. (I haven't done this but know 2 people that have had this happen to)

[Haggy]

	Quote: Originally Posted by Scotty
	Here is the last couple - I have to go away with work tomorrow for a few days then the DA challenge this weekend so realistically Monday will be the maiden - will get some more pics together Friday in the daylight.

Looks awesome, congratulations! The colour scheme looks impressive.
I have been flying the 2x2 for sometime now, I am keen to see how the 2.12 goes. The pipe tunnel in the 2.12 looks a whole lot neater!

Cheers
Haggy

[~SnApRoLl]

	Quote: Originally Posted by catman3070
	If anyone is considering using washers behind the standoff, I wouldn't recomend this. If you notice before tightening fully that the stadoffs don't sit flush. This is what causes the ears to break of the engines. (I haven't done this but know 2 people that have had this happen to)

Hey CatMan,
I talked to one of the reps at DA and he said using washers behind the standoffs would be ok. But I'm leaning towards cutting some small properly angled spacers to set the thrust angles to allow the engine to be mounted flat or I will have a new plywood firewall cut with the angles needed. It be a little more work than needed but if it will save my $600.00 engine from a possible breakage it will be worth the extra time and labor. I will let you know how it goes when I get to that stage in the construction.


Shawn

[~SnApRoLl]

	Quote: Originally Posted by Gary Powers
	No sidethrust, Shawn, but a ton of downthrust built into the fiberglass firewall. To achieve the proper sidethrust and up thrust required 1/4 and 3/8 inches of washer on the bottom stand offs. I don't think it's a problem, but I was not expecting that much diversion. Other than that, everything is going well. I bought the associated header and cannister and discovered last evening there is no way to insert a mounting bolt on one side of the header, but that should be easily solved by cutting the head off of a bolt and inserting into the engine, then using a nut to secure it to the header. Hope that makes sense. Gary

Thanks for the heads up on the firewall Gary . One question though, Can you tell me exactly how many washers you have behind each standoff? And do you have any pics you can post? As this will help me design a new plywood firewall with the proper angles built in.

Thanks
Shawn

[TEKE]

Shawn Forques Research can machine you stand-offs with thrust angle and different lengths. Not to pricey.

Carl

[~SnApRoLl]

	Quote: Originally Posted by TEKE
	Shawn Forques Research can machine you stand-offs with thrust angle and different lengths. Not to pricey. Carl

Hey Carl,
I called Forgues Research and they said it would be $25.00 for the standoffs PLUS $35.00 to machine the angles in them PLUS $10.00 shipping! So I'm looking at $70.00 for standoffs. My Uncle has a lathe and I'm going to ask him if he can machine me a mounting plate with the thrust angles machined in out of aluminum bar stock.

Shawn

[Scotty]

	Quote: Originally Posted by Haggy
	Looks awesome, congratulations! The colour scheme looks impressive. I have been flying the 2x2 for sometime now, I am keen to see how the 2.12 goes. The pipe tunnel in the 2.12 looks a whole lot neater! Cheers Haggy

Thanks Haggy the pipe tunnel is probably the single biggest improvement over the 2 X 2. The fuselage is actually identical in dimension (from the same mould) as the 2 x 2. They have however stiffened the sides with thin ply or maybe MDF which makes it a little harder to twist. The only other differences are the cowl mounting which is much simpler than lining up all those tabs on the 2 x 2, the slightly bigger wings, the robart hinged stabs which can give massive throws, the only other difference is the canopy which frankly is a nightmare to fit and certainly in my case is a retrograde step from the 2 x 2.

More soon.....Scotty

[Scotty]

Hi Guys, Have just flown the 2.12 - and it flies great. I pushed the limit a little on the C of G and started at the recomended aft of the range (which seemed to work great on the 2 x 2) and unfortunately it was a bit tail heavy and sensitive in pitch. So I will move the batteries forward and try again later next week ( gotta spend the weekend at the DA Challenge!). It certainly had plenty of power and appeared to track well. I didnt have enough people around to get any video although here are a few inflight shots.

[Scotty]

	Quote: Originally Posted by ~SnApRoLl
	Thanks for the heads up on the firewall Gary . One question though, Can you tell me exactly how many washers you have behind each standoff? And do you have any pics you can post? As this will help me design a new plywood firewall with the proper angles built in. Thanks Shawn

Hi Shawn, To answer your question I ended up with 3 2 and 1 washer under three of the four standoffs. I hope this makes sense to say 2 washers of right thrust required and 1 washer of upthrust required so the one standoff on the bottom right that needed both right and up got three washers. Hmmm think I had better take the cowl off and get a few close ups for you. To help reduce the side loads at the engine end I drilled the firewall holes slightly on an angle and made sure the engine bolts were tight first. I agree this isnt perfect but so far hasnt presented any problem to do.

More Pics soon...

[Onewinglow]

Can anyone advise if HS-5955TG servos will fit in the servo bay space available. From the manufacturers specs the Hitec are slightly bigger than the recommended JR 8511's but appear to be less expensive and a better servo.

[marpman]

My Blue,Red,Yellow scheme, CompArf Extra 2.1 arrived this week.
Not that I really like either colour scheme they have for the Extra 2.1 but it saves time not having to paint it.

Assembled the wings, rudder and the rear stabs just to see what it looked like.
Must say the model looks much better in real life than the pics shown on the CompArf website.

Noticed that the carbon spar for the rear stabs is way too long by at least 20mm, one of the stabs wouldnt butt up against the fuselage.
I will have to cut it down to size not that much of a problem.

[Gary Powers]

	Quote: Originally Posted by catman3070
	Gary, If you install the rear bolt before the header is tight. Then cut down a allen wrench to fit. This should help with the install.

Catman, I appreciate the thought, but I cannot get any kind of bolt throught that hole except from the motor side. Much too tight an angle. I would send pictures, but am not at home for a few days.

Gary

[Gary Powers]

	Quote: Originally Posted by ~SnApRoLl
	Thanks for the heads up on the firewall Gary . One question though, Can you tell me exactly how many washers you have behind each standoff? And do you have any pics you can post? As this will help me design a new plywood firewall with the proper angles built in. Thanks Shawn

I'll try to get some pictures Sunday night or Monday when I get back to El Paso. I am using 1/8 inch nylon washers and used two on one side and three on the other to get the correct thrust angles.

Gary

[Gary Powers]

	Quote: Originally Posted by TEKE
	Shawn Forques Research can machine you stand-offs with thrust angle and different lengths. Not to pricey. Carl

Carl, that's a heck of an idea and thank you? I will explore that option!

Gary

[~SnApRoLl]

I got my Extra today. BUT!!!!!! here is the scoop.
1. The right hand stab is cracked at the hinge line.
2. Most of the Robart hinges in the stabs are crooked and binding the elevator throw.
3.The bottom hinge line on the left hand wing is not cut straight there is
at least an 1/8" or more gap at 2 points. (The hinge line on the Right hand wing is fine.
4.The anti-rotation pins on the right hand wing do not line up with the holes in the fuse. (The left hand wing fits on the fuse fine)
5. The holes for the rudder wire was not drilled all the way through, it wont go through the top of the rudder, also they forgot to drill the hole at the top of the rudder.
6. There is some chipped paint on the top of fuse at the front of the built-in cowl top.

Click here for pictures.

http://www.rcgroups.com/forums/showt...627161&page=61