Canister Mounting

[Shakes]

Ok guys, I have a 102" QQ Yak, DA-100 and MTW canisters.
I used a dremel to grind down the aluminum L-brackets that the gear mount through, which incidentally are exposed inside the canister tunnel, to make sure there was no metal to metal contact.

I'm still paranoid about this as the flex headers seem to allow the canisters a little movement. Every couple of flights I have to re-position the canisters as they seem to be moving closer to the L-brackets.

So, without cutting out a lot of foam, removing the landing gear, and cutting off part of the L-bracket I'm trying to think of something to do.

The mount from DA used silicone tubing to hold the canisters in place. I was thinking of taking some silicone fuel tubing, splitting it so that it wraps the canister a little and applying some high temp red RTV to the tube and the canister. Then wedge them back in.

Will the heat melt the tubing? It doesn't effect it in the mount - I'm assuming that is because of the distance to the header? I know silicone/tygon type tubing should not be used for smoke because it melts - just wondering if its ok on the canister itself.

[RollingHarrier]

Hey Shakes
The canister is cool enough it shouldn't melt the silicon. I'm not sure the RTV will adhere the silicone to the canister though. I would build a buffer with the silicone between the aluminum landing gear L brackets at the canisters. Basically mounting the silicone to the air frame and not the canisters. Just be sure not to block off airflow past the canisters so they won't get too hot.

[Shakes]

Thanks!

Not sure how I'll mount it to the airframe but I'll hopefully figure out something. Even if I could just get some silicone squeezed in there enough to hold and not come out during flight I'd be happy.

It's a very difficult area to work in.

[Temptation]

Ship your plane to me, and I'll install them for you. The silicone tubing works great, mounted in four positions around the perimiter of the can. I support my cans in the front and rear. This makes sure you don't break any headers. Maybe two mounts isn't necessay, but I can gaurantee my system will never break headers. The key is to not allow the headers support any of the cans weight. There are so many different ways to mount cans in a plane. It boils down to how picky you are, and how much time you have. The system I made is pretty involved and time comsuming. When it's done you have a bullet proof mounting system. I will try to post some pics of my set up for you to take a look at.

Mike Darr

[Temptation]

I am going to attempt to attach some pics here. Hopefully I do it right. If it works you will see the installation of MTW 110 K cannisters with MTW 90mm drop flex headers being installed in my 40% Carden Cap 232 with a DA 150. Yes the cans fit rather well. I did need to cut one inch from the length of the headers to obtain the needed wing tube socket clearance. This did not affect the performance of the engine at all. In fact the engine runs great with plenty of power. The midrance transition is smooth as silk. I love it. Nice and quiet also. Keep in mind, if any of you ever decide to run cans on a Cap and your cans are this close to the wing DO NOT run a carbon wing tube. The heat will soften up the epoxy and the tube will fail. No, I have not had this happen to me, but I know a couple of guys that it did happen to. I know that when I disassemble my plane after running the engine the aluminum tube is pretty warm.

I hope these pics help. In my opinion this is the best mounting system there is. The opening is just the right size to allow the cans to slide in easily, but not allow the cans to flop around. All I need to do to remove the cans is unbolt the headers from the engine, and slide them out. Very easy. No need to even get inside the plane. The inspection cover in the cockpit is just in case I ever need to replace the silicone tubing.

[Biff]

Pretty work Mike! The other thing that helps a ton is to put a screw through the coupler clamps. Right into the pipe inlet and header end. This ensures the cans won't move back. They will if you don't put the screws in.

[Temptation]

	Quote: Originally Posted by Biff
	Pretty work Mike! The other thing that helps a ton is to put a screw through the coupler clamps. Right into the pipe inlet and header end. This ensures the cans won't move back. They will if you don't put the screws in.

Biff, if I don't will I be screwed? Thanks for the tip. What I actually do, is run the engine and allow it to get up to temp. Shut it down, until everything cools, then fire it back up until she gets up to temp again. Shut it down again and let everything cool. If you do that when everything is new and clean, they won't ever go anywhere. Little trick I learned from a good friend of mine.

Thanks for the kind words. I will do a build thread on this plane when I get it done. I am having to much fun flying it right now to tear it all apart right now and redo everything.

Here is a picture of what the inside looked like when I got it.

[Biff]

Mike, what header length did you end up with?

[Dennis C]

	Quote: Originally Posted by Temptation
	Thanks for the kind words. I will do a build thread on this plane when I get it done. I am having to much fun flying it right now to tear it all apart right now and redo everything. Here is a picture of what the inside looked like when I got it.

Hey Mike looks good...you flying at R.C.C.D.

[Temptation]

	Quote: Originally Posted by Biff
	Mike, what header length did you end up with?

Bob, final length of the headers was 11 inches.

Mike

[Temptation]

	Quote: Originally Posted by Dennis C
	Hey Mike looks good...you flying at R.C.C.D.

Thanks Dennis, yeah I've been flying it at RCCD. I wonder how long it will take for the fun police to put an end to that?

Mike Darr

[aerografixs]

That is one nice installation, are you using flex pipe wrapped with tefflong tape ???

Roger

[Temptation]

	Quote: Originally Posted by aerografixs
	That is one nice installation, are you using flex pipe wrapped with tefflong tape ??? Roger

Yeah, they are the MTW flex headers, and they came from the factory with the teflon tape already installed. After only 10 runs the white teflon is now brown and black. This tells me tht the flex portion is leaking pretty bad. I was thinking of just tig welding in a section to eleminate the flex, but I was told that the header pipe is to thin, and it will just tear outside of the welds. Maybe a piece of teflon as a coupler is in order here.

Mike Darr

[Biff]

Mike, no problems welding the headers. We do it all the time. You obviously need to have the right settings. The guy who welds my stuff is without doubt an artist. Have never broken a weld.

[Dennis C]

	Quote: Originally Posted by Temptation
	Yeah, they are the MTW flex headers, and they came from the factory with the teflon tape already installed. After only 10 runs the white teflon is not brown and black. This tells me tht the flex portion is leaking pretty bad. I was thinking of just tig welding in a section to eleminate the flex, but I was told that the header pipe is to thin, and it will just tear outside of the welds. Maybe a piece of teflon as a coupler is in order here. Mike Darr

I oftened wondered about doing that.(.getting rid of the flex pipe ). but it would seem that the airframe would take alot of abuse from the vibration not including the electronics and such. i wish they would come out with something more flexiable like a rubber tubing.