n00bs Gonna Build a Carden

[gareth.ky]

I think its gonna be great.

The Python QQ was flying on the 85 is 24 3/4 pounds. I don't see why I can't make that weight. The only place it was ever sluggish was on pulling out of a hover and even then it was very adequate.

[gareth.ky]

Here's Johnny!

Some construction progress too:


Adding the hardwood support blocks and canister tunnel ceiling support. I used 30 min epoxy for the hard wood and CA for the balsa.


Can you say BIG PIPE?!?! I thought you could, now hold still...


Adding the back plate with 30 min epoxy. All the but joints on the motor box will get the epoxy treatment.

So the motor needs to be mounted some 38mm in front of the firewall, thats 1 1/2 inches. DA doesn't support the use of standoffs. The firewall doesn't have the thrust angle built into it. So I have to fabricate something to make it work.

Should I stack up 6 sheets of 1/4" aircraft ply and get to cutting or is there a better way?

[vatechguy3]

call scott at swb manufacturing.

he should be able to make something for you.

i use his mounts in both my 35% carden and my 40% carden.

tony

[gareth.ky]

I'll send him an e-mail.

Looking at the problem in detail I could easily mess this up. I would need a band saw to cut the offset. The big hole in the part is actually elliptical, 70mm on one side and 80mm on the other. Looks something like this:

Motor Mount.png

[mark786]

Gareth,
Doesn't need to be too fancy. I have attached a picture of what Aero-Works supplies with their planes. Of coarse theirs has the offset built in to the firewall so that does add a step of complex to yours.
Mark

[bodywerks]

Doesn't the engine box already have the appropriate right thrust built into it? If not, build it into it so you don't need to make a complicated mounting block - simple.

[gareth.ky]

The Carden motor box parts build up square. They supply some pre-cut 1" hard wood dowels with the right thrust in them. They are made for the DA 100 and too short of the 85. This is one of the misses in this kit.

I'm leaning towards cutting a longer set of dowels and using a ply plate up front to mount the motor on. Something like this.

[gareth.ky]

So I spent the last two days making a motor mount. Well I spent one day failing to make a motor mount and the next day making up for it.

I posted this in the DA-85 Mounting Thread. It's 6 layers of 1/4 ply laminated with poly glue. First i drilled the holes and so forth while its still a square block. Then I used the belt sander to make the 2.5 degree right thrust. I used CAD to calculate how much material to remove. Then I added a 1/8" ply backplate to make the sanded end fit flush with the firewall. My digital angle finder says I'm within 0.1 degree of perfect. Good enough for me. It weighs 3.3oz. I'm not too worried about the weight up front, I'm hoping to put the Rudder servo in the tail.

Thanks Dan for pointing me in the right direction. Now the firewall is getting glued in and tomorrow I should have the motor box finished up.

Question: what doe you do for the header screw thats in the bend of the 'question mark' header? I guess this might apply to any header. i got the recommended M5-16mm screws but they are too long to fit. I assume I need a shorter screw. Is there some trick to mounting headers?

[Neil4]

I not trying to be like a smart a$$ or anything but is there a reason you put the blind nuts in backwards on the backside of that mount you made?

[tommy321]

I'm one of the many skulkers on this thread, and am really enjoying it... please keep it up!!!
On my DA-50 header, I had the same trouble as you... the screw can't be made to fit with the header curve.
I ended up cutting the screw short enough that I could get it into place (there was still lots of thread left to go into the engine cylinder).
I also found I couldn't get a normal allen key into to tighten the screw. I had to take my Dremel cut-off wheel and cut it off close to the bend.


A real PITA if you ask me
Tom

[gareth.ky]

	Quote: Originally Posted by Neil4
	I not trying to be like a smart a$$ or anything but is there a reason you put the blind nuts in backwards on the backside of that mount you made?

Naaaa, thats just for the photograph so I didn't have to hold the thing on. The blind nits are in the firewall now.

[why_fly_high]

I like it but it looks more like 2.5638 degrees to me.

Keep it up!

Dan