Vacuum bagging our Ez - why/why not

[Aclouston]

While following the Zeigler's build, I'm trying to wrap my head around the rationale behind vacuum bagging so many parts. Besides marginal (this is my assumption) weight savings, compared to correct stripling/squeegee technique, it looks like a lot of time and resources invested. I contacted them to inquire if the nose wheel well was bagged as well ( I should get a reply soon).

 The roundness of this part would make me beleive (I'm new to bagging) that it's one of the most difficult part to manufacture by vacuum mainly because of the plug fabrication and also the weght saving and required esthetic doesn't seem to justify the complexity of the method. I beleive those parts ( nose cover wheel well and front gear strut inner cover) are no more produced by third parties any more.

Is vacuum bagging one of the more (efficient, cost effective) process to produce those complex shaped parts?

[Kent Ashton]

As you probably know, Burt's "moldless composite construction" was a revelation that allowed a fast airplane to be built without a lot of tooling.  Over the years that I have followed canards, lots of people have come up with great ideas to improve his method which significantly increased the build time.  For example, the Cozygirrls have had some good ideas and talk about their "Lo-vac" technique but AFAIK, their airplane has not been completed.    (last update 2008:    http://www.cozygirrrl.com/menupage.htm     I argued this with fellow for years.  He had some good ideas but AFAIK, he never completed his project    http://www.n200lz.com/   Then there are builders who wanted to build molds for the perfect airplane.  https://www.canardzone.com/forums/topic/21972-sales-ive-seen/?do=findComment&comment=63573     and https://www.facebook.com/Raptorairworks    Great ideas, lots of work, but they never came to much.  I could find more of them if I wanted to take the time to look.  

It is hard enough to build a canard airplane as it is.  Vacuum bagging is one of those build-time drags that (IMO), requires a lot of preparation time and adds mess to the build with only marginal payoff.  As they say: "Perfect is the enemy of good-enough".   Build a good-enough airplane and go flying.  However, it is the building that motivates most of us so if vacuum-bagging seems like fun, go for it.

 

Edited June 30 by Kent Ashton

[Aclouston]

Thanks Kent. Always straight to the point. I love that. 🤩

I read that your suggesting that if one's really care to build within a reasonable time frame, then make a decent foam mold of the wheel well and strut cover, layup 2×bid, and move on...

Or, if lucky, obtain those odd parts from a partial project.

So you know (and since you are my major correspondent), I'm almost giving up on the idea of finding a decent quality project (Vari or Long) close to Montreal. So my head is now focusing on a new build, much to my deception...

[Kent Ashton]

1 hour ago, Aclouston said:

So you know (and since you are my major correspondent), I'm almost giving up on the idea of finding a decent quality project (Vari or Long) close to Montreal. So my head is now focusing on a new build,

I see a fair number of projects that would make a good start.  Building from scratch is fun but it can be very cost-effective to buy someone's project--you usually get lots of materials at less than cost and the builder's labor for free.  Price of materials has really gone up since I was building.  Most projects that I see I would call "decent quality".  There was an EZ last year that had  a big square hole (holes?) cut in the aft face of the center-spar.  I believe it is in the Sales thread.  That problem looked pretty questionable to fix.  I don't know what happened to it but otherwise, most problems can be fixed.  For example, strakes could be cut away and rebuilt.  Instrument panels that don't suit you can be removed and rebuilt.  Noses can be cut off and built to your spec.  This one recently for $7K is a deal.  Comes with an engine and the rest is free.

https://www.facebook.com/marketplace/item/1026448509084991/

[Aclouston]

Problems that you mentionned do not scare me. After all, our canadian DAR dictates that we reconstruct all flying, control surfaces and the cs/spar.

The scary parts are the multiple trips to inspect and the transportation x/c. For the one you mentionned, It should be about $6000-$8000 from Reading CA to Montreal. Me and a renthal is probably ~$2000 but that's not the way a had planned to visit the usa.

[Mike S]

 

Not sure if you saw my earlier post to you about a project with all the materials to finish the airframe. A very good builders log for all the work to date comes with it. Sounds like what you're looking for.. 

https://eastnc.craigslist.org/avo/d/aurora-rutan-varieze-long-ez-project/7787732989.html

You'll have to source a canopy and nosegear metal parts. 

I'm currently out of the country. Back next week, going to Indiana in mid Nov. Could bring it that far...

Rgds, Mike

[hdmx]

Am 30.6.2024 um 17:40 schrieb Aclouston:

Besides marginal (this is my assumption) weight savings, compared to correct stripling/squeegee technique, it looks like a lot of time and resources invested

You don't only get ligher parts, vacuum bagging comes with a few other advantages like better compaction, better adhesion, and better overall strength of your part. If possible, you should always be using vacuum bagging. Especially with planar parts it's a no-brainer because you don't even need a mold

[Marc Zeitlin]

3 hours ago, hdmx said:

You don't only get ligher parts, vacuum bagging comes with a few other advantages like better compaction, better adhesion, and better overall strength of your part. If possible, you should always be using vacuum bagging. Especially with planar parts it's a no-brainer because you don't even need a mold

Given that vacuum bagging was an available technique when Burt designed the Varieze, Long-EZ and Defiant, what is your position on why he didn't recommend it in the cases where you believe that it's "better". It's not like he wasn't aware of the technique...

[hdmx]

Am 4.11.2024 um 17:12 schrieb Marc Zeitlin:

Given that vacuum bagging was an available technique when Burt designed the Varieze, Long-EZ and Defiant, what is your position on why he didn't recommend it in the cases where you believe that it's "better". It's not like he wasn't aware of the technique...

Ease of construction for homebuilders - a lot of techniques were known back then. Of course you were also able to have a sleek fuselage and and streamlined canopy but obviously be opted for a much simpler construction that requires fewer tools, is cheaper, and faster. I mean that's pretty obvious, isn't it? Not all parts can be properly vacuum bagged, especially with the moldless construction. So introducing vacuum bagging to a couple of planar parts wouldn't make sense really if you have to buy everything. But if you already have the equipment, you should definitely go for it