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Old Nov 03, 2009, 03:55 AM
Will fly for food
Maryland
Joined Sep 2004
8,424 Posts
I used Econokote on my first BattleAxe. Everyone else is using packing tape without problems. Yes, you want to overlap it at least 3 - 4 mm.
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Old Nov 03, 2009, 11:28 AM
Gary James
gsjames's Avatar
Weatherford, TX
Joined Feb 2006
267 Posts
Yes, colored packing tape is the way to go for COST and weight. Some guys are lightly spraying the wing with 3M 77 (or is it 78 now, the one that doesn't melt foam) to get EVEN BETTER adhesion. I've never had a problem with it lifting except once on an airplane where the exhaust from the muffler was blowing directly on a forward facing edge of a tape seam.

Overlap it a little, say about 1/4" or so. I also frequently "iron" it down a bit with a MonoKote iron to get the adhesive to soften and stick to the foam better. It also helps take out any inadvertent wrinkles.

You DON'T have to cover the ENTIRE wing with BiDi tape. After a couple of pieces it really doesn't add much "armor" and it does add weight. KEEP 'EM LIGHT! One of the best tricks that I have learned from Evan Wenger is to use 3/8" diameter poly tubing (for refrigerator ice makers) in place of the wooden or fiberglass dowel rod on the leading edge. It lets the L.E. "give" a little in mid-airs but tends to bounce back whereas the wood just breaks. Don't glue it in, just tack it in place with a little 3M 77 to keep it aligned while you tape over it with the BiDi.

Yes, Brandon's "Badger" looks a lot like an Avenger but it has a lower parts count. The engine mount is a HDPE cutting board. The towel bar is slotted and the mount is bolted in.

I've seen some pretty fancy tape schemes done by AJ Seaholm and by Eric Wenger. There are some nice pics in the www.rccagallery.com

"Don't fall in love with a combat plane"...
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Last edited by gsjames; Nov 03, 2009 at 11:36 AM.
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Old Nov 07, 2009, 07:39 AM
Martin - AKA mr.sneezy
PLMS's Avatar
Adelaide, Australia
Joined May 2004
1,692 Posts
Hi Guys,

Our first few combat planes are nearly ready. I should be able to test fly mine tomorrow.

The last thing to do now is work out how the rubber bands are retained below the fuz. It looks like some sort of dowels under it.

Can anyone tell me whether the dowels are fitted though the aluminium rails or held underneath somehow, and how big they are ?

I wonder if drilling holes in the rails is going to weaken the fus right in the middle where there will be maximum load in a crash. I'm thinking they should not be drilled...
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Old Nov 07, 2009, 09:06 AM
Gary James
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Weatherford, TX
Joined Feb 2006
267 Posts
Here is one way, the other way is just to strap a dowel under the rails with a rubber band
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Old Nov 07, 2009, 09:54 AM
Registered User
Blue Note's Avatar
East Tennessee
Joined Nov 2007
151 Posts
Quote:
Originally Posted by PLMS View Post
Hi Guys,

Our first few combat planes are nearly ready. I should be able to test fly mine tomorrow.

The last thing to do now is work out how the rubber bands are retained below the fuz. It looks like some sort of dowels under it.

Can anyone tell me whether the dowels are fitted though the aluminium rails or held underneath somehow, and how big they are ?

I wonder if drilling holes in the rails is going to weaken the fus right in the middle where there will be maximum load in a crash. I'm thinking they should not be drilled...

The Battle Axe uses two dowels ( 1/4" I think ) which are not attached to the plane until you apply the rubber bands. It can be a little tricky to get them in place at first, but I have found if you retain the dowels with the rubber bands that go around the box first, it's not too bad. In this case, you drill no holes through the rails and they may be a little stronger. One thing to note is without a landing skid, you'll be landing on the rubber bands and often times you will break one or two and it will shift the dowels out of place from dragging on the grass.

In method two, I have been fixing standoffs actually to the rails to address both problems. With the rigid ( no. 6 or no. 8 ) screw through the entire diameter of the hole in the rails, and the screw being harder than the aluminum rail itself, I have found to sacrifice in durability, but it is much cleaner and more convenient to use.

Good luck.

BNC
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Old Nov 08, 2009, 12:35 AM
Martin - AKA mr.sneezy
PLMS's Avatar
Adelaide, Australia
Joined May 2004
1,692 Posts
Thanks

Thanks for the advice guy's.

I've ended up combining methods and used a 4mm CF solid rod as the dowels, and drilled 4mm holes in the rails close to the top. Hopefully the rails won't bend there when it becomes a 'lawn dart' in the future.
I pushed standard fuel tubing over each end to hold them in place, and help retain the rubber bands.

Here are the results of your help. This is first one in the club fully finished off, and maybe the first SSC class model in the state for all I know.

Martin
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Old Nov 08, 2009, 08:35 AM
Will fly for food
Maryland
Joined Sep 2004
8,424 Posts
I will bet that drilling that large of hole in the frame rails will turn out to be a not good thing. Considering we have bent the rails in midairs.

I use 3M 1090 from the craft store for coating the wing before taping. It is designed to be used on styrofoam.
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Old Nov 08, 2009, 09:18 AM
Registered User
Blue Note's Avatar
East Tennessee
Joined Nov 2007
151 Posts
Just in case, I would also try and make a point to cross you rubber bands diagonally across you wing to help with twisting and stability ( see picture 1 ). With the single servo in the middle it can be challenging, but worth the effort. Also, make sure you put the last rubber bands back and forth from peg to peg to "lock" all of your other rubber bands on ( picture 2 ). This will help a lot to keep them from slipping off - followed by you wing.

BNC
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Old Nov 08, 2009, 10:13 AM
Gary James
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Weatherford, TX
Joined Feb 2006
267 Posts
There is probably going to be a big difference in strength between putting a 1/16" diameter hole in the rails and a 4 mm hole. I made a couple with 4-40 bolts (1/8th" dia hole) to hold the rubber bands and it is still going strong. But two of them did bend at the hole during a crash.
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Old Nov 08, 2009, 05:03 PM
Martin - AKA mr.sneezy
PLMS's Avatar
Adelaide, Australia
Joined May 2004
1,692 Posts
Quote:
Originally Posted by Pinecone View Post
I will bet that drilling that large of hole in the frame rails will turn out to be a not good thing. Considering we have bent the rails in midairs.

I use 3M 1090 from the craft store for coating the wing before taping. It is designed to be used on styrofoam.
Yep, you're all right. It bent in the first crash right at the first hole. (Doh !)

I got a 60 second maiden flight before the Corona 2.4Ghz receiver went off air, and it crashed. Apart from a smashed prop and spinner (fitted so I could use my starter easier) there was very little damage. The damage being a 2 degree or so bend in the rails, right at the first peg hole.
Straightened it up ok by pressing it down over a log.

Seems to me from my inadvertent crash test that the rear peg hole may be OK where stress is much lower, but I will delete the front from when building the next one (for my son in the photo).

The good news is that during the first 60 seconds it was clear that the model is stable, it's going to fly great when dialed in fully.
Martin
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Old Nov 11, 2009, 08:35 AM
Will fly for food
Maryland
Joined Sep 2004
8,424 Posts
I find a Battle Axe SSC to be a great sport plane. Durable, fun to fly, stable, but responsive. My number 1 plane to fly.
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Old Nov 11, 2009, 04:56 PM
Martin - AKA mr.sneezy
PLMS's Avatar
Adelaide, Australia
Joined May 2004
1,692 Posts
I've done a bunch of short test flights with our new SSC now.
I had to increase wing incidence to trim out the elevator, and add reflex to trim out the tucking, drop the elevator throw as well to avoid it snap rolling if yanked hard.
Now that it's 90% dialed in I can say it's good to fly. It's very responsive. Reminds me of my old control line combat models.

Martin
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Old Nov 11, 2009, 09:56 PM
Gary James
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Weatherford, TX
Joined Feb 2006
267 Posts
Quote:
Originally Posted by PLMS View Post
drop the elevator throw as well to avoid it snap rolling if yanked hard.
Martin: On the next batch of wings, put in about 3 degrees of washout to stop the tendency to snap.
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Old Nov 12, 2009, 12:26 AM
Martin - AKA mr.sneezy
PLMS's Avatar
Adelaide, Australia
Joined May 2004
1,692 Posts
Quote:
Originally Posted by gsjames View Post
Martin: On the next batch of wings, put in about 3 degrees of washout to stop the tendency to snap.
Good idea, we'd thought about it a bit when cutting the test batch, but decided to see how it went without.
However what is the effect of washout on pulling tight outside loops (e.g. bunt the model) ?
Would washout actually make it snap easier in that direction ?

I like flying that manoeuvre so it's relatively important to me it behaves the same both ways as much as possible.
Martin
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Old Nov 12, 2009, 09:01 AM
Gary James
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Weatherford, TX
Joined Feb 2006
267 Posts
Quote:
Originally Posted by PLMS View Post
Good idea, we'd thought about it a bit when cutting the test batch, but decided to see how it went without.
However what is the effect of washout on pulling tight outside loops (e.g. bunt the model) ?
Would washout actually make it snap easier in that direction ?

I like flying that manoeuvre so it's relatively important to me it behaves the same both ways as much as possible.
Martin
You will probably find that the airplane doesn't do outside loops all that well anyway. It "bunts" just fine but mine don't do outsides very well. I wouldn't worry about it. Of course, you could just cut one set of wings with washout as a test case and decide what you like best. You could try a fully symmetrical airfoil section if you like to do a lot of outsides, just like control line combat. One of the guys in this area is flying Russian-style wings and they do outsides quite well.
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