Grumman obsession ... and other.
- Thread starter hsquier
- Start date
Quinlan Sauter
Active member
oh my what an excellent built!! looks amazing!! can i find plans anywhere?
hsquier
Junior Member
I can edit pdf for you
Witch one ?
ThomasMartino
Elite member
Wow! That looks fantastic!
Quinlan Sauter
Active member
hsquier
Junior Member
The glider is a Super Sinbad
You will easily find plans on the web at different size.
I enlarged the plan in my local paper shop for a 120 cm wing span.
I had a lot of fun to build this old timer.
The only modification was the airfoil, I used a much thinner Neelmeyer airfoil : Very happy with the result with a very large speed range.
Especially very low end speed tolerance.
You will easily find plans on the web at different size.
I enlarged the plan in my local paper shop for a 120 cm wing span.
I had a lot of fun to build this old timer.
The only modification was the airfoil, I used a much thinner Neelmeyer airfoil : Very happy with the result with a very large speed range.
Especially very low end speed tolerance.
hsquier
Junior Member
Did some small work ...
Finished wing covering
Lamination film gives a nice surface aspect
Made some reinforcement for battery scratch holder and for undercarriage if secondary wanted (not initial project).
Good painting friendly confirmation of lamination film
no excuses for a neat paint job.
Finished wing covering
Lamination film gives a nice surface aspect
Made some reinforcement for battery scratch holder and for undercarriage if secondary wanted (not initial project).
Good painting friendly confirmation of lamination film
no excuses for a neat paint job.
Attachments
hsquier
Junior Member
I'm not reasonable.
Remember step two ? Choice of material.
Should be easy going ... Quick little project ....
Do you know what happens to an old Rc builder when he try to do Depron ?
He just can't do without balsa.
Why ???
I don't really know, education footprint ? like having still pleasure to listen an old Led Zeppelin's Immigrant song.
Did someone say blasa flies better ?
All in all, perhaps genetic.
Remember step two ? Choice of material.
Should be easy going ... Quick little project ....
Do you know what happens to an old Rc builder when he try to do Depron ?
He just can't do without balsa.
Why ???
I don't really know, education footprint ? like having still pleasure to listen an old Led Zeppelin's Immigrant song.
Did someone say blasa flies better ?
All in all, perhaps genetic.
ThomasMartino
Elite member
I’ll say it, balsa flies better. Every time I start a foam build I quickly decide I could do it better with balsa.
That fuselage is flawless. Every joint is perfectly fit. Your attention to detail is apparent.
That fuselage is flawless. Every joint is perfectly fit. Your attention to detail is apparent.
Hear that a lot, but what’s the reason for that?
ThomasMartino
Elite member
I’m sure I will miss something obvious here but I will try my best. There is a magic to balsa planes. They really do feel different in the air. I think it’s a lot of small things that add up to make a noticeable difference in flight. One of the best things about balsa planes is their stiffness. A well designed balsa plane can weigh less while being a lot stiffer and stronger than a molded foamy or a foamboard plane. This makes them fly very true because there is no airframe flex of flutter. This stiffness also makes it easy to accurately trim the aircraft and know that it will always fly like it’s on rails. Balsa planes are also usually more aerodynamic. Balsa lends itself well to nice curves and thin trailing edges. My foam gliders have 3/16” thick trailing edges on the wings and that creates a lot of drag. Due to the nature of their construction, balsa planes usually have real airfoils. This pays off in efficiency and predictable stall performance. Another advantage is the glossy smooth surface of the covering film. They slip through the air effortlessly. My foamies usually look and feel pretty rough after a season of landing in grass and getting dinged up in the car.
The biggest advantage that I think is worth emphasizing is how durable and long lasting balsa planes are. My molded foamies all flew great at first but eventually the foam begins to fatigue and the hinge lines start to break and things get scuffed up and after a few seasons the plane just doesn’t look or fly the same. I have the same problem with my foamboard planes. I live in Georgia where the humidity level is almost always 90-100%. I’ve built dozens of foamboard planes in the last couple years because unfortunately they just don’t last in the weather here. They start to warp from the moisture and the paper delaminates around the hinges resulting in sloppy controls. I love building with foamboard but I pretty much only use it for prototyping these days since I know the planes will start to feel sloppy after a week. My balsa planes can fly in any weather (I’ve even flown in light rain plenty of times). I’ve never had any problems with warping or parts wearing out. My oldest scratch built balsa plane is still good as new after three years. I also have a secondhand Gentle Lady glider that was built over 30 years ago and it still looks and flies great.
Also balsa planes don’t turn into toothpicks after a crash. That’s a myth. I’ve crashed plenty of balsa planes and I’ve only written off one of them. The broken parts key back together perfectly and can be repaired with thin CA in seconds. The biggest pain is repairing the covering film.
Anyways, that’s my opinion, I hope it didn’t come across as a rant. I’d love to hear other people’s opinions on the matter. I love foamboard planes and store bought foamies, but when demanding flight performance and longevity is a requirement I prefer balsa or composites.
hsquier
Junior Member
Wow !
You said it all.
What can I add ?
As teenager I learned RC flying with balsa.
Early Flite test (2005 ?) made me came back to RC - Foam gives the promise of speed build (a revolution to me) and is non dusty.
But ...
As ThomasMartin said only balsa (and compose, but technically a level further) gives you this level of precision both in detail and in respecting the desired shapes.
And when you suffer of mental obsessions, balsa is the best tablet.
You said it all.
What can I add ?
As teenager I learned RC flying with balsa.
Early Flite test (2005 ?) made me came back to RC - Foam gives the promise of speed build (a revolution to me) and is non dusty.
But ...
As ThomasMartin said only balsa (and compose, but technically a level further) gives you this level of precision both in detail and in respecting the desired shapes.
And when you suffer of mental obsessions, balsa is the best tablet.
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hsquier
Junior Member
Illustration of
When you are happy with a build :
You feel disappointed when you have this after 2 flights.
And all the more when you realize Balsa construction would not have taken much more time and would have allowed an invisible repair.
When you are happy with a build :
You feel disappointed when you have this after 2 flights.
And all the more when you realize Balsa construction would not have taken much more time and would have allowed an invisible repair.
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Yeah, but I'm scared of cutting out all of those tiny formers and stringers by hand- I don't have a laser cutter! That F6F is beautiful btw
ThomasMartino
Elite member
I understand your trepidation. It can be tedious and time consuming. I cut all my formers and ribs by hand for years. At first I hated it, but over time I got better at it and it became enjoyable. Turn on a movie or TV show and it can actually be very relaxing.
Eventually I wanted faster production and complex shapes so I purchased a Cricut Maker. For about $300 I essentially had a CNC controlled x-acto knife. It works great. I have used it to cut at least 500 ribs.
Last summer I finally had the cash to by a laser cutter and it has been a huge time saver, but I still cut parts by hand sometimes. It’s not always worth the trouble of making a CAD file.
hsquier
Junior Member
Thanks, it touches me, really. But you'll see how ironic life can be !
In fact I also suffer from trepidation !!!
I was so happy with this balsa version idea I rushed into construction without a really completed plan :
I made though stupid youth errors :
As nothing has really been thought, Controller mount was by default left to non elegant zip ties.
No suitable space left in design for receiver, rudder and elevator servos ...
No room for aileron servo ...
And at last : unfavorable final judgment :
Too heavy.
What I "learned" from general aviation is that our RC builds are many scales too stronger (and so heavier) comparative to scale planes :
This is the interior of our Jodel 112 : The sides are 2 mm plywood et the frame 15 x 20 spruce for the thick ones.
What scale plane could be lift by holding only one wing like we does for almost every of our RC planes.
But I admit low weight has a price : No scale plane can be survivor of some of our usual dirty RC landings ... or crash ...
Leading to the only possible end :
But don't worry, I'm stubborn :
3 vs 4 mm for the frame,
Controller and receiver will be inside vs outside profile
Passthrough holes have been made between adequate partitions for cables
Right spacing for servos ...
And 34 gr before sanding.
Ok, this will be the one.
ThomasMartino
Elite member
The new fuselage looks even better. Having the radio gear stowed away will be nice. Side note, have you ever considered making a scale model of your Jodel 112? It seems like it would make an excellent RC plane.
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