Comp arf build question

[Flyinrazrback]

I am putting together a comp arf mx2. Question is to get the cans to fit in the plane, there will be 2 big holes in the bottom portion of the motordome to accomodate the cans. That is not my concern. My concern is when the holes will be cut, the holes will go into the carbon fiber reinforcement strip on the bottom half of the motor dome by about .5" on each side. Is this a problem, or should some extra reinforcing be done once the holes are cut out? This mx2 only has a single strip of carbon fiber on the motor dome seam. The last mx2 I received the entired motor dome was carbon fiber. It looks like they skimped on this one, and do not want this one to come apart.

[pepatrick]

It shouldnt be that way...What size are the headers..

[Flyinrazrback]

Its a 3W 170 with the 3W cans, which are 3.35" x 14" long. There is no way to fit them in the plane without the front of the can sticking out of the bottom portion of the motor dome. The MTW 110K cans are quite a bit shorter and is what is in the manual for a DA 150, but these are too small for the 3W. I was going to use stock mufflers on the 3W, but the cowling is butchered a ton to fit them in and looks bad IMO.

[Flyinhigh]

It sounded a little like good salesmanship, but could have just as well been fact .....

I called my Comp-ARF rep and asked about the lack of Carbon fiber in the dome and the rest of the MX-2. He told me all the newer Comp-ARFs are built that way now, but are reinforced with Kevlar and other materielas I haven't even heard of to be just as if not stronger. It just looks different.

This sounds like it may be a good question for Ray Labonte - he builds and flies many of these, and if he isn't sure, he can call Adrean and ask him directly.

[Flyinrazrback]

I don't think there is any kevlar in this airplane. After further inspection the carbon fiber strip on the motor dome/seam is not even glued on all the way.

[Flyinhigh]

I have some spots like that on my MX-2 and my E260 - I got the impresion the CF strip was more of a laminating-assist than actual structure becauses of that - just something to look good. I know the motor-dome on my MX is as hard and sounds the same as the CF dome on my E260 - I don't want to sell you on believing it is as strong though - I didn't make it. I had to call in to the rep to be assured, myself. Ray did tell me the missing CF has been replaced with Kevlar in the vacume process. Hopefully not seeing it doesn't mean it isn't there. I can't even remember what the other two materials are that were mentioned, but I distinctly remember him saying it is just as if not stronger - the CF has become subject to availability (I know - likely excuse)
Maybe you could shoot something like a .22 at it to confirm the presence of Kevlar

[Jaybird]

Good Lawd! a 170 in a MX2! That will be just about right!!

[Flyinrazrback]

A 170CS at that! .

[Extra260]

Its like putting a 170 on a 35%... SWEET!!!

[sweetpea]

	Quote: Originally Posted by Flyinrazrback
	A 170CS at that! .

You so crazy!!!!!


Let me know if you decide to sell that beast! (motor only)

[JagerBomb]

I go around the holes and laminate carbon tow, It may not be nec but it usually stiffens it up

[Dan767]

Charles,

I put two carbon fiber strips and glassed over them in that area on my comp arf Extra 260 Kiwi after I cut the holes for my cans. I didn't want the dome collapsing either. I also glassed the landing gear top, front and sides with West systems resin and a coarse glass weave. I had to remove a portion of the landing gear block to get my cans in. You will also need to use JR servo grommets (the metal portion) to get the servos mounted in the wing with the stock screws.