Dumas L-19 Bird Dog
- Thread starter roversgonemad
- Start date
roversgonemad
Member
I did find out that the Hangar 9 Parklite can shrink enough to warp the crap out of the little bird dog! I flew it, and it pulled left really hard! Upon closer examination, I had shrunk the covering too much on the right wing, really altering the shape. Not sure how I missed it earlier! I had to pull the covering and fix some broken bits. I am a little bummed, I had covered the wing in one piece on the top, now I have a seam, but at least it's straight. Weather permitting, flight #2 in the AM.
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Turbojoe
Elite member
Wow. The Parklite is the same as Solite. I've used a ton of Solite and never warped anything but I've never done 1/16" stringers either. I'll have to weigh out the 1/8" basswood that is coming against the 1/16" balsa and decide if it's worthwhile to make the mod and hopefully be able to balance the plane. Both Dumas kits may be a no go for me. Bummer.
Joe
Joe
Turbojoe
Elite member
So do you guys think 1/8" basswood is viable behind the CG for stringers? I'll have 48 of 'em when they arrive today. As I've said 1/8" balsa stringers are tough enough for me. 1/16" is simply out of the question for stringers. If 1/8" won't work then both kits are back on the for sale block....
Joe
Joe
roversgonemad
Member
I think you could do 1/16" bass stringers, but I think the 1/8 would put you over the weight that allows a Triltle design to fly so well. I know a lot of guys strategically use bass wood for areas where the plane is handled.
I heard the Solite is actually lighter than the Parklite, and doesn't shrink as hard. I found that I should have shrunk with my iron only, and not used the heat gun. I've got a plane just about to come off the table, and I'm going to cover it with the SIG light weight covering. Once I get to the covering, I'll post my thoughts.
I heard the Solite is actually lighter than the Parklite, and doesn't shrink as hard. I found that I should have shrunk with my iron only, and not used the heat gun. I've got a plane just about to come off the table, and I'm going to cover it with the SIG light weight covering. Once I get to the covering, I'll post my thoughts.
roversgonemad
Member
Flight report:
This little plane is a seriously slow flyer! At 8.25 oz with battery, it's a real lightweight! I am getting nearly seven minutes from a tired 500 mAh 2S. It does do rolls, loops, or any other aerobatic things, except maybe a hammerhead turn. What this plane does really well is relaxes the pilot! It looks fierce, but she's a total sweetheart! I did have to mix rudder with the aileron stick. I am terrible at flying three channel planes, because I am so used to the rudder on the left stick. I really ought to just move the servo to the rudder and not bother with putting it on the aileron channel.
EDIT: FINALLY able to upload a picture! I have a serious love/hate relationship with anything Apple, but all I really use is my iPad......
This little plane is a seriously slow flyer! At 8.25 oz with battery, it's a real lightweight! I am getting nearly seven minutes from a tired 500 mAh 2S. It does do rolls, loops, or any other aerobatic things, except maybe a hammerhead turn. What this plane does really well is relaxes the pilot! It looks fierce, but she's a total sweetheart! I did have to mix rudder with the aileron stick. I am terrible at flying three channel planes, because I am so used to the rudder on the left stick. I really ought to just move the servo to the rudder and not bother with putting it on the aileron channel.
EDIT: FINALLY able to upload a picture! I have a serious love/hate relationship with anything Apple, but all I really use is my iPad......
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Turbojoe
Elite member
She looks great!
Flight report sounds like my Mountain Models C-180. Nice and relaxed. Maybe I'll drag my Dumas L-19 kit out next for build. I've got more than enough fast planes. These little floaters just seem to be so much more fun in a different sort of way. When I fly my old C-180 slooowly past at eye level I always have a ridiculous grin on my face. I'm sure this little L-19 will produce the same effect.
Awesome job on yours Rover....
Joe
Flight report sounds like my Mountain Models C-180. Nice and relaxed. Maybe I'll drag my Dumas L-19 kit out next for build. I've got more than enough fast planes. These little floaters just seem to be so much more fun in a different sort of way. When I fly my old C-180 slooowly past at eye level I always have a ridiculous grin on my face. I'm sure this little L-19 will produce the same effect.
Awesome job on yours Rover....
Joe
roversgonemad
Member
Believe it or not, it is flying slower than the video makes it appear. It looks fast in the video, but it's anything but!
Konrad
Posting Elsewhere
Yes, The MM C180 and Dumas L-19 fly very similar. I like Dave Blum's designs a bit more than Pat Tritle's, this has more to do with the airfoil.
On the subject of covering no Parklite and So-lite are not the same (very close but not the same). Parklight is a german product from the firm that makes Oracover. So-lite is from an english firm that makes Solarfilm.
The product I now use for these "Stick & Tissue" type builds is called R. A. microlite. Its virtue is that it is much more thermally stable than So-lite. That is it doesn't sag near as much in the sun or summer heat. As a bonus it is also lighter. The only draw back is that it is a higher heat type covering, so may not be suitable for covering over foam.
https://www.homefly.com/products.asp?id=31 (Now called Microlite)
When shrinking these films on ultra light RC models. Use an iron at the lowest setting that will shrink the film. Think of the film as a metal. If you over heat it the "temper" will come out. For films this means they sag real easily for the rest of the model's life. Stay away from the parameter of the part with the iron. You don't want to reactivate the film's adhesive and debond it from the perimeter of the part.
As to basswood the design is large enough to use 1/8 just fine. Not sure why you would want to unless the balsa is so light as to be unsuitable for longerons. A structural note that for the same amount of wood you can use four 1/16 stringers for every 1/8 stringer. This helps make smoother better looking model parts (smaller facets).
Don't know if Dumas has corrected the wing spar but take a look at this thread if you actually plane to fly the model. Cuban Eights and ground loops (dragging the wing tip on the ground) have been know to over stress the Dumas spar!
https://www.rcgroups.com/forums/showthread.php?879893-Dumas-spar-in-their-Electric-R-C-kits
(Pat actually joined the conversation around page 10)
All the best,
Konrad
P.S.
With real light structures, like on 18" RC models, I'll use two irons one on each side of the surface to control warping.
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