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-   -   Vacuum bagged construction? (https://www.rcuniverse.com/forum/rc-jets-120/11649161-vacuum-bagged-construction.html)

kohersh 05-24-2018 04:44 PM

Vacuum bagged construction?
 
Does anyone know of any manufacturers that utilize vacuum bagging techniques in the production of the composite models? be them jet airframes, hotliners, or prop driven?
If so who are they, which model(s) and is it predominately a fiberglass layup with cf reinforcement panels or is there a full carbon air frame out there somewhere ( and yes I know cf impedes RF ;))
Thanks all!

ChuckC 05-24-2018 06:45 PM

Uh...most of them?... Ultimate Jets does a great job on their SR, which is full carbon.

Even garage builders like me use it: very old, established method. Only way to get optimum resin to cloth ratio.

Whatcha' got in mind?

Harley Condra 05-25-2018 02:16 AM

BVM has been vacuum bagging for years.

kohersh 05-26-2018 10:45 AM

OK cool info, one further question on the BVM stuff, I've seen the "How's it made" TV show that went through the BVM factory and that sure was cool, but what about their PNP line, pretty sure those are not made 'in-house' and PLEASE correct me if I am wrong I am not trying to propagate bad info....so are those vacuumed also?

Chuck C, the reason for asking is just general knowledge assembling to try and compare jets I have owned or seen in person for comparison. I am thinking of doing my own airframe just for fun...as you say a 'garage build' and I just am looking for points of reference. While I've laid up glass before it was never for a complete model and it was never bagged, so that would be a learning process for me
Anyone know about the Elite Shockwave or Havoc, Or the T1 or Pilot's composites, Sebarts stuff...that's Krill right making the composite Avanti's??

brosi 05-26-2018 11:07 AM

Hi,
that´s easy. I use it right now: Starfighter
the layup is 2x50 g/m² , 3mm Honeycomb, 1x50 g inner layer. Carbon as you like. Sorry for metric scale

best regards
Andreas

kohersh 05-26-2018 12:11 PM

aswesome!. I failed to ask about Tomahawk and Airworld, those are 'top dog' mfg's Is it a safe assumption those are bagged?

SECRET AGENT 05-27-2018 05:58 AM

I would imagine that in todays quest for larger, lighter airframes that construction techniques are similar across the board.

sidgates 05-27-2018 07:29 AM

https://cimg9.ibsrv.net/gimg/www.rcu...91d385dcb8.jpg
When I started my scratch build project I had planned to vacuum bag all the molded parts. A friend who had a lot of molding experience said if I was diligent about removing excess resin I could do almost as good as vacuum bagging. I think I was successful. The fuselage is 83in long. I used one 2oz and one 10oz layer the full length and an additional 3oz layer from wing trailing edge to the nose. The left fuse half weighs 1lb 3.6oz and right half is 1lb 3.8oz. The left half is shown above. The finished airplane is 21.5lbs dry. I had estimated it would be 22lbs. I feel that vacuum bagging isn't worth the extra work for most home projects.

Link to more build details: F-94C PROJECT

invertmast 05-27-2018 02:15 PM

If the manufacturer has the word “sandwich” in the description of the model, its 100% vacuum bagged.

Nearly all (matter of fact, now that YA isnt as available as it used to be, i cant think of a single manufacturer) are vacuum bagged. Some are just done more poorly than others.

kohersh 05-27-2018 06:26 PM

Turning into an interesting discussion. Please anyone else feel free to chime in. Nice work Sid!

ChuckC 05-29-2018 10:05 AM

There are TONS of videos on the topic; easy learning. Most of the good ones come from the fiberglass supply distributors. I got one of the "Vacuum bagging secrets" DVD's from a guy that made competition glider wings and fuselages. Like a 4 DVD set. Phil Barnes maybe? Been a while. Good set and shows easy techniques for doing ultra-lightweight/epic strong wings and how to "paint in the mold" (without using a mold; using mylar).

Makes it a ton easier to sheet wings also.

TUMBLER 05-29-2018 02:54 PM

I molded my F-100 and found it difficult to bag because the edges would pull away from the mold. I know it can be done but I struggled with it and after spending hours laying up a fuselage half I didn’t want to risk wrecking anymore trying it. My fuse is exactly 2lbs and can’t imagine I would be able to shave much much off a fuse this size.

https://cimg6.ibsrv.net/gimg/www.rcu...4e59e2f82.jpeg
https://cimg7.ibsrv.net/gimg/www.rcu...926c67aa5.jpeg
https://cimg8.ibsrv.net/gimg/www.rcu...295a77385.jpeg
https://cimg9.ibsrv.net/gimg/www.rcu...0b631653b.jpeg
https://cimg0.ibsrv.net/gimg/www.rcu...bf145e990.jpeg

TUMBLER 05-29-2018 03:50 PM

I do have to bag the flying surfaces though which are a layer of 1.4oz glass then a layer of 1/16 balsa and then another layer of 1.4https://cimg5.ibsrv.net/gimg/www.rcu...6d44511d8.jpeghttps://cimg6.ibsrv.net/gimg/www.rcu...1040b1c53.jpeg
https://cimg7.ibsrv.net/gimg/www.rcu...0efb8d327.jpeg

ChuckC 05-30-2018 07:58 AM

That's enough internal structure to keep it strong enough for flight?

I've always wondered what it'd take to make a hollow molded wing hold together... Guessing the main wing has a bit more internal structure/spar support.

Great looking plane; great project, BTW.

Si_B 05-30-2018 08:10 AM

That F100 is just gorgeous.

TUMBLER 05-30-2018 09:27 AM

That picture above is my stab. You’d don’t need much inside. Even on a wing you dot need much.

Here is another wing mold I did.

https://cimg1.ibsrv.net/gimg/www.rcu...a0e7949a6.jpeg



Originally Posted by ChuckC (Post 12436302)
That's enough internal
structure to keep it strong enough for flight?

I've always wondered what it'd take to make a hollow molded wing hold together... Guessing the main wing has a bit more internal structure/spar support.

Great looking plane; great project, BTW.


ChuckC 05-30-2018 02:26 PM

wow! Whats the lay up schedule for the wing? Guess its truly a stressed skin design. Nice.

TUMBLER 05-30-2018 02:40 PM

Same as the stab. 1.4oz, 1/16 balsa, and 1.4oz. The sandwich creates a very strong wing. If you were to press on the open areas of the completed wing it feels like a solid foam sheeted wing

TUMBLER 05-30-2018 03:25 PM

Thank you! It’s a 24lb electric because at the time I built it, they banned turbines everywhere around me, but I’m currently converting it to a turbine.


Originally Posted by Si_B (Post 12436307)
That F100 is just gorgeous.


ChuckC 05-31-2018 04:12 AM

Yeah, that F100 deserves nothing but the finest fuel and noise! Sorry for all the questions, but did you have to do much more for internal structure on the F 100 wings, or just the same?

Thant'll be it...for now, unless you pique my interest again. I promise :-)

TUMBLER 05-31-2018 04:17 AM

https://cimg2.ibsrv.net/gimg/www.rcu...e3fb04a73.jpeg
https://cimg5.ibsrv.net/gimg/www.rcu...d6b633aae.jpeg
https://cimg7.ibsrv.net/gimg/www.rcu...ceaf4900a.jpeg
https://cimg8.ibsrv.net/gimg/www.rcu...15cc6f592.jpeg
Feel free free to ask away!!! For the F-100 wings I just used traditional foam sheeted wings and an aluminum wing tube. Nothing fancy there unfortunately. I have thought about molding the wings at some point though.



Originally Posted by ChuckC (Post 12436557)
Yeah, that F100 deserves nothing but the finest fuel and noise! Sorry for all the questions, but did you have to do much more for internal structure on the F 100 wings, or just the same?

Thant'll be it...for now, unless you pique my interest again. I promise :-)



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