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Old May 27, 2012, 06:35 PM
AvB
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Scratcho

Sorry to start a new thread, but I've been writing stuff about my own-design plane, the Scratcho, for a while now. It's featured in lots of reports, videos and had a starring role in the recent USA International DS trip. I think it's sensational, and now that I have a few others who agree I thought it deserved a thread of its own!

The Scratcho is a fully molded 64" (160cm) slope and DS fun plane, with the emphasis on toughness, good looks and all round fun for frontside and DS. Not designed to be a record breaker, but to give the whole DS experience.

I will write some more another time and will probably copy other posts and videos in here. But I'll start off with this video that Jarred put together the other day. Sorry if you've already picked it up elsewhere.

AvB

Scratchooo 1.mov (10 min 10 sec)
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Old May 27, 2012, 07:01 PM
AvB
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This one shows some of the process of building the lastest light Scratcho. It's using a unique method ... molding the skins, then bonding (epoxy and vac bagging) half-cores into the skins; and hot wire cutting them flush with the flanges ... then putting in a spar and aileron stiffeners, plus Ampreg round the edges ... to give a perfect combination of a molded shape with the durability benefits of a tough blue foam core and Ampreg behind the edges.

Teflon coated glass and other clips of light Scratcho moulding (12 min 42 sec)



And this one shows that wing just out of the mold, and a few issues:

Light half-core molded Scratcho wing just out of mould. (6 min 31 sec)



And this one shows the maiden flights and some DSing at Bandicoot a couple of days ago:

Last day of flying at Bandicoot Ridge - 26 May 2012 (21 min 56 sec)
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Old May 27, 2012, 07:58 PM
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I really want a Scratcho! I am having Scratcho withdrawal symptoms! Such a fun plane
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Old May 27, 2012, 08:38 PM
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I want one too...

Please pass the Scratcho!

Chris
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Old May 29, 2012, 12:22 PM
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AvB,

no longer fly Bandicoot?why?

Just love your building clinic vids, keep comming it!

André
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Old May 31, 2012, 04:13 AM
AvB
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I've done stage 1 of making a new nose cone mould. The old one is the original and is the first mould of anything I ever made! It has a few repairs that now make it impossible to get a good paint finish ... it is not really good enough for the bladder technique (gets leaks) and it's a funny shape that's hard to clamp. So I'll make an improved version.

Andre the owners at Bandicoot have some family and insurance considerations that led them to make the decision that they can't have us visiting. I can't describe it all in detail online. But yes it's very sad. An amazing place, and it's become the place I just think of when I think about going flying. Makes me sad thinking about it.
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Old May 31, 2012, 08:08 AM
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Andre the owners at Bandicoot have some family and insurance considerations that led them to make the decision that they can't have us visiting. I can't describe it all in detail online. But yes it's very sad. An amazing place, and it's become the place I just think of when I think about going flying. Makes me sad thinking about it.
Hi Andrew look forward to seeing the video of the mold making process. Is it possible that we may be fly bandicoot on a once a year special occasion type basis or we will get it back in the future, sounded like a great spot.
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Old May 31, 2012, 08:11 AM
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That's really sad AvB, can't imagine something like that happening here at my spot...
Australia has plenty of DS spots, go find them

Scratcho! Scratcho! Scratcho!
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Old May 31, 2012, 10:08 AM
DS state of origin NSW Vs QLD
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Originally Posted by AvB View Post

Andre the owners at Bandicoot have some family and insurance considerations that led them to make the decision that they can't have us visiting. I can't describe it all in detail online. But yes it's very sad. An amazing place, and it's become the place I just think of when I think about going flying. Makes me sad thinking about it.
Live and learn mate.
I bet theres alot of What Ifs going through your head.

Pete
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Old Sep 03, 2012, 08:36 PM
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Woke up to find some weird things in my garage this morning:
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Old Sep 03, 2012, 08:38 PM
AvB
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Haha! Very glad they got there OK. Very thankful to Bernd for taking them over with him on his work trip! Saves a mint in freight! Very much looking forward to hearing your flying reports!!
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Old Sep 04, 2012, 07:49 AM
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Look at those sexy beasts - Fly the pants off them Alex!

Btw... Andrew you know you can kiss your Scratcho record goodbye now right?
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Old Sep 04, 2012, 07:51 AM
AvB
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I'm looking forward to it!
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Old Sep 04, 2012, 11:24 AM
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AvB, I really enjoyed your video on molding your A/C part's. As much as I know about working with composites since 1971 at Grumman I am alway's willing to learn. I liked your mold alighnment device's, I use drill point button head screw's to do the same thing. The teflon you use was known to me to be Tedlar TX-1040 it came in porous and non-porous style's. That's interesting that you use upper and lower mold halves for your wing's. I almost did that in fabricating Greenland style kayak paddle halve's but I was going to apply a very thin coat of resin and then throw some 1/2in. chopped fibre on it, flip it upside down and when the resin was almost cured I would then mix up some 2 part foam and pour it over the chopped fibre so there would be a mechanical bond between the skin and the foam. Later both halves would be bonded together.I should try one like that as I'm retired and have been making a few mold's for some sloper's lately. In the slope forum check the thread about dancing and the Tango. Good luck on you molding adventure's. Dave.
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Old Sep 04, 2012, 05:26 PM
AvB
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Thanks Dave ... good thoughts there. What do you mean by "A/C's"? Sorry I'm a bit slow, not enough sleep.

There is a lot more to add to this Scratcho thread that's gone into other threads now! Especially the stuff on making a foam filled PU wing, expanded in the moulds: http://www.rcgroups.com/forums/showthread.php?t=1721451

I made up a light fuse last night to go with the light wing and tails. This will be the lightest one yet. Painted white in the mould. I am finding the whole process easier since I made templates for the various sections I wet up into the mould. I am really chuffed because I pressurized the inflation bladder to 25psi and it didn't leak at all!
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