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General control line discussion => Open Forum => Topic started by: Blaine Buchtel on December 20, 2016, 03:52:16 PM
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I'm interested in drawing and building a C/L biplane which could do a quality pattern. Any thoughts about what design features might make this possible? Any input positive or negative would be appreciated!
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ther is some information on the site, do a search on here and you should turn up some information, John Miller designed and flew one a few years back that was reasonable
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Tom Niebuhr has done it for you. Search for "Vagabond" on this forum for plans and discussion. There is also the "38 Special," a very capable biplane, kitted by maybe Brodak. Claus Maikis in Germany has a very pretty biplane on his "Ukie" web site with plans available. I assume you are talking about a .40 size and up model, not half-A or something that size.
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I am indeed wanting a .40 or larger model.
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Have a look at a Stearman dating from the 40's. JC Yates had the first one, powered by an Orwick 64. I think Don Hutchinson has plans.
Floyd
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I am indeed wanting a .40 or larger model.
You pretty much have to have a big one. Someone mentioned John Miller's biplane design. He took the same approach I did, specifically, high aspect ratio to reduce the induced drag and to provide more roll damping for the amount of wing area. If you are going to design one, that's whre I would start.
Brett
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Don Hutchinson's Stearman is a beauty and it was published in FM magazine. Iy is patern proven. Tom Dixon also has a Pitts Special plan available. His Pitts is straightforward to build but it needs a .60 for power.
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40 size so, each wing would be about 300 Squares? I guess a bi-slob has 600 sq. if you could keep it from flip flopping and such.
MM
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Was a page in A.M. or M A N on " The 59 er " back in the 60s . So club flying developing fox 59 powered aerobatic / stunt Bipes .
If anyones got / recalls it , would they post it here , please ??????????
Copostellas THING was high placed in the euro Champs . Might be your best bet if your looking to fly F2B with it .
(http://www.fiamaero.it/newsmedia/compostella/Compostella.jpg)
(http://www.riviste-di-aeromodellismo.it/files/links_interni/le_foto/compostella.jpg)
(http://stunthanger.com/smf/open-forum/mr-luciano-compostella/?action=dlattach;attach=130445)
Im inclined to build a 59er if someone finds the thing . a dimensioned sketch was on it . have to be classic , if not old time legal . >:(
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And there's 'Biceps', one I always wanted to build but man, what a lot of wing ribs!
http://www.airplanesandrockets.com/airplanes/biceps-article-plans-apr-1969-AAM.htm
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I have the Biceps plans. One day I may get around to building one but that would be quite a project for me. I have other planes I want to build and no time for everything. If I decide to do it I would see about getting the wing ribs laser cut.
I also wondered about doing the wings in foam to reduce building time but I am not sure if the increased weight would be too much. And, would wing strut attachment be more of a problem with a foam wing?
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I have the 38 Special and it does a very respectable pattern. Still working the bugs out on Tom's Vagabond. The Bi-Slob needs to be reconfigured, to do a competitive pattern, but it will do the pattern.
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Hutchinson Stearman
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A few years back, I was a consulting engineer for Agusta Helicopter in Coscino di Costa, Italy.
I always timed my trips so that my meetings would end just before the weekend. That way, I could fly with Luciano and his friends.
I saw the Falco fly and it was amazing - Actually, Luciano was amazing, an incredibly smooth flyer.
He was European champion six times, mostly I believe with biplanes.
I never saw the Puma but the Falco was powered with an OS Surpass 48.
Luciano gave me the plans that Matt posted - see that he signed them to me. I still have them.
When I worked in Italy, I was fortunate enough to become friends with Luciano, Clemente Cappi, Alberto Maggi and Massimo Semoli. All really fine people.
But, to the topic at hand, a properly set up biplane works - works very well!
Bob Z.
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Hutchinson Stearman
Not only does that Hutchinson Stearman look great, it flies quite well. In the hands of Bart Klapinski, I believe it won the OTS event at the VSC several years ago. And it did a presentable modern pattern as well. It is based on the Palmer/Yates design from Air Trails.
Keith
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Staggerwing.
This one flies very well.
SAITO 56, three station retracts, take-apart.
Bob Z.
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Another view
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Some related info located here:
http://stunthanger.com/smf/open-forum/why-no-competitive-biplanes-in-stunt/
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Elwyn Aud should still have my version of the Sheeks Staggerwing. Much better plane than this old pilot.
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Here's a link to Claus Maikis "Duetto" plans at Hippocket:
http://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=2450
(http://www.hippocketaeronautics.com/hpa_plans/data/thumbnails/32/duetto.jpg)
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Steve Helmick...was the "Dancing Girl" discussed some years ago? A design out of the U.K.?...or is my mind still gone?
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Was a page in A.M. or M A N on " The 59 er " back in the 60s . So club flying developing fox 59 powered aerobatic / stunt Bipes .
If anyones got / recalls it , would they post it here , please ??????????
Im inclined to build a 59er if someone finds the thing . a dimensioned sketch was on it . have to be classic , if not old time legal . >:(
The 59'er was my design, and was actually an accidental success. But it WAS a success as far as a decent pattern. I do not have any plans for it, but I think I can recall enough to sketch it out. While Brett went high aspect ratio to conquer the drag thing, in my (very) rookie knowledge of aeronautics, I went thinner airfoil.
My big old Fox 59 drug that thing around in some horrific wind a few times, so I guess it worked.
I built the thing in 1964, flew it for a couple of seasons before going "hi tech" as my buddies called it.
My building techniques were not the greatest, and I eventually had to retire it to the burn pile because of fuel soaking problems. (That big old Fox about shook it apart that third season.)
One thing Al Rabe mentioned in his article about it was the tail wag in square corners, but I think as I look back that more than half of that was a rookie stunt flyer's overcontrolling. Al's rudder would likely solve the problem.
My place is a train wreck right now because of our fresh move, and my new shop is still in the organizing stage, but once I get some clear time I'll look up which AAM magazine it was published in. (Not as a construction article, but In Al's article. That same article featured Jack sheeks' Stagger wing and a cropduster by another pilot.
I'm thrilled that some of you noticed the bird, and when I get situated here I'll be more than happy to furnish you all I can. My cell is 419-966-2036 or you can message me here. email is wlhint@centurylink.net
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Steve Buso designed, and Johnny Duncan built, a bipe several years ago....high aspect ration.....
Have fun!
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Elwyn Aud should still have my version of the Sheeks Staggerwing. Much better plane than this old pilot.
Almost forgot about that one!
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Bart Kaplinski did pretty well with his Fleet biplane flying in Old Time at VSC.
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Bart Kaplinski did pretty well with his Fleet biplane flying in Old Time at VSC.
Elwyn,
Do you have a photo of John Calentine's Travel Air. Published in MAN, Jan 52, by Jim Hunt (Bob Hunt's dad). John flew it several times at VSC. Did a credible OTS pattern.
Keith
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I'll look, but I think that's one I missed.
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(Clip)
Al's article. That same article featured Jack sheeks' Stagger wing and a cropduster by another pilot.
(Clip)
The two page article on bipes that Al did was in the Jun 73 issue of American Aircraft Modeler. Al compiled notes from several flyers including Jack Sheeks, Jean Pailet, and Will Hinton. Will's "59er" looks pretty good.
Keith
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Steve Helmick...was the "Dancing Girl" discussed some years ago? A design out of the U.K.?...or is my mind still gone?
The Dancing Girl was published in MAN, Feb 75, by Peter Dominic Miller, from England. He discusses the evolution of the design, using negative incidence on the top wing (as in deBolt's Bipe) going from 10% wing section to 18%, and a follow up on his articles on biplane design in Aeromodeller, Jul 74, and his Dutchess in Aeromodeller, Aug 74. Miller suggests that the Dancing Girl is the result of a long line of biplanes, lots of trial and error and recommends not changing anything. This would be a good place to start. .40 power, plans are available from the AMA plans service.
Keith
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Just scrolling through my down loaded plans...there's one here called "Biceps" by Donald Yearout. Fox .59 is mentioned (outlined) in the nose. Looks like maybe a copy of a magazine plan...April 1969 American Aircraft Modeler page 26 and 27.
FYI
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The Dancing Girl was published in MAN, Feb 75, by Peter Dominic Miller, from England. He discusses the evolution of the design, using negative incidence on the top wing (as in deBolt's Bipe) going from 10% wing section to 18%, and a follow up on his articles on biplane design in Aeromodeller, Jul 74, and his Dutchess in Aeromodeller, Aug 74. Miller suggests that the Dancing Girl is the result of a long line of biplanes, lots of trial and error and recommends not changing anything. This would be a good place to start. .40 power, plans are available from the AMA plans service.
Keith
This "Duchees"
(http://www.hippocketaeronautics.com/hpa_plans/data/thumbnails/32/duchess.jpg)
Link to the hippocket plane is here:
http://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=1639
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I have built and flown the Biceps with ST .60 it has flaps top and bottom wing. 50" span over 700 sq in wing area! I have a Laser cut kit now as the first one was a lot of work cutting ribs and
half ribs. I used a plywood template and simply cut the ribs out that way. Not too difficult to build and flew pretty well. I had the control horns set up way to
fast on the first one. I know for a fact that Don H Stearman flies very, well. So I guess it depends on what you wanted to have a biplane for.
If I were going to compete I would use Dons Stearman with an LA .46 or equivalent. The Biceps is Classic legal however so you could use that also.
This is a picture of a picture so not very clear of my Biceps around 1979
(http://i64.tinypic.com/1t0tqd.jpg)
(http://i65.tinypic.com/osbt01.jpg)
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John Miller designed a good looking stunt biplane called the "Two-Bits."
http://stunthanger.com/smf/stunt-design/almost-finished-with-it-my-stunt-biplane/?all (http://stunthanger.com/smf/stunt-design/almost-finished-with-it-my-stunt-biplane/?all)
(http://stunthanger.com/smf/index.php?action=dlattach;topic=19379.0;attach=98466;image)
(http://stunthanger.com/smf/index.php?action=dlattach;topic=19379.0;attach=72191;image)
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Bob Reeves' Dancing Girl
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I will echo what some others have said about Don Hutchinson's Stearman as I have flown it and it flew very well. I am going to build his profile Stagger Wing this winter to campaign next year, It should also fly very well.
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Inclined to try this. With thin symetrical airfoil .
(http://aerofred.com/data/thumbnails/71/Bristol%20F2B.jpg)
(http://www.wingnutwings.com/ww/vA240BCB9/www/products/model_kitsets/32004/archive_photos/Bristol%20F.2b%20Fighter%20C814%20Keith%20Park%20MC%20(via%20David%20Wilson).jpg)
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(http://farm9.static.flickr.com/8468/8114018581_1802cab448.jpg)
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I want to thank each of you who responded to my post concerning what would make a competive aerobatic biplane. I never thought I would receive so much usefull information! There is much " food for thought" in your posts. I' m so glad I asked for your input. I 've already ordered some of the recommended plans and expect to use and design an excellent plane based on the work of others. Thanks again and Merry Christmas to all.
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Chuck Holtzapple (sp?) was working on one interview in the early 90s. I remember seeing build pics in SN and asked him about it at the 90 nats if memory serves.
Any memories or pics of Chuck's bipe?
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Hi Bruce! I remember Chuck's bipe, that was how he and I met. It was a sleek looking ship, but when he and I shared information at the '90 nats, he hadn't flown it extensively if memory serves me right. Buried somewhere deep in my "stuff" are a couple of pictures, and also a picture of Chuck and I holding my last 59er together at that same nats. That was my first nats and probably my most memorable one; what a time I had!
I'll keep on the lookout for the tote with pictures in it and then go through it. If I find those, I'll post them here on a new thread. But...says he as he shakes his head, don't hold your breath, this place is a train wreck right now.
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Here's a couple pics of the Jim Hunt Travelair. LA46 power. Does a nice old time pattern but no snappy turns!
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This is the best bipe stunter I have ever watched. Mr,T's TIGHT, powered by Saito 82(?). He got 10th place at '11 Japan Nats. Not only flew very well but also was very beautiful and won the most beautiful model of the year prize. No plan, sorry.
Aki
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This is the best bipe stunter I have ever watched. Mr,T's TIGHT, powered by Saito 82(?). He got 10th place at '11 Japan Nats. Not only flew very well but also was very beautiful and won the most beautiful model of the year prize. No plan, sorry.
Aki
Thats awesome
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I was going through some plans just a few minutes ago and came across one called The Zephyr. I didn't unfold it all the way but it's a profile bipe in the vain of the .38 Special, I think. Does this one ring a bell with anyone? Not sure how I got the plans. I have seen a couple of .38 Specials fly in our area and they fly QUITE well. Another one on my to do list. The Hutchinson Stearman in the full fuse version or his profile version would be in there also along with his Staggerwing. A Beucker Jungman or Jungmeister would thrill me also especially the Jungmeister done up in Bevo Howard colors!
I just spent the day clearing off my work bench, and laying out a wing for a box stock Twister. been wanting to do a Mike Gretz memorial model in the box art colors. When that is framed up and off the board, I might have to get a profile bipe out of my system also. We have a new member in our club that has been emailing with me with questions along the lines of this thread so maybe I oughta do this while everything is fresh in my head!
MERRY CHRISTMAS and HAPPY NEW YEAR!
Dan McEntee
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One thing I was really wanting from this post was some idea of what percentage of airfoil " cord vs. camber" for a great flying biplane. I would have thought a thinner airfoil would be needed, but I see many of the suggested designs have a fairly thick wing. What's up with this? Regards, Blaine
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(http://arc.aiaa.org/na101/home/literatum/publisher/aiaa/journals/content/ja/2013/ja.2013.50.issue-1/1.c031111/20160414/1.c031111.fp.png_v03)
I Hope thats Pefectly Clear , then . mw~ n~
Adding camber doesn't necessarily reduce aerodynamic drag; it depends on the airfoil shape. If too much camber is added, the flow over the airfoil may not stay attached to the wing even at an angle of attack of zero. When this occurs, we say the flow has separation over the airfoil, if the entire top of the wing has separation, the wing is stalled. Wings with camber don't as a result have the ability to produce more lift in general. As an example, the C-5 is a heavy lift aircraft used by the US military; in order to produce the lift needed, one might think it uses a cambered wing, but its wing is symmetrical. Cambered wings will produce lift at zero angle of attack, but as mentioned, too much camber can also be a bad thing.
CRIKEY .
GAP Vs Chord was regarded as ' the issue ' due to ' interfearance ' , as they called it . Generally Acepted Gap ( Between Wings ) should exceed ( Dimension of ) Chord , to avoid
interaction between the airflow of the ' stack ' . Presumed to cause problems . Likely as at its inset irregular , thus oscillatory .
Maybe withem closer it doesnt , even if it is ' interfearance ' ing , or Interacting , more correctly . ( oops a pun ) .
A merely personal perspective is it aint neccesarilly neccesary to get optimum lift . As thered be a fair bit available . If looks ( amoungst other things - Like Center of drag per wing vertical distribution , and its constancy %^@)
wernt considered .
Thus do we consider it Two Monoplanes Flying in Fixed Formation , or Seperate from a mono plane . :( A Split Monoplane would have ' outside camber ' / ' Flat Inside ' ( or the reverse ) wings , if the projected area ( with no stagger )
was considered purly as in plan view . S?P
Or perhaps more sensably Two Planes ( :## Bi Plane ! ) of half the thickness of a monoplane ( approx ) viewd same .
Id Think Thick Wings , to avoid interfearance , like Biggles . Would Need a Gap exceeding 10 x the Thickness ( Thereabouts ) of a wing .
(https://s-media-cache-ak0.pinimg.com/236x/09/9f/ef/099fef134d4b160b66b8735598b52b44.jpg)
Whats BIGGLES Doing in a salmson B2 . %^@ U S Air Service used these in France , in ' the great war ' . Great for the industrialists obviously . But im not to sure who else benifitted from it . :-\
Were Americans Subjected to the whiles of BIGGLES , or is that more a Empire & King sort of delusion . :-\
(https://awritersden.files.wordpress.com/2015/06/450px-airco_dh-4.jpg)
Be Straightforward to base one on , having strong ties to America . Especially when the petrol ran out and you had to jump . :( U.S. Mail Plane .
https://www.youtube.com/watch?v=dWc8udN7Bgw
Youll Note this is a good Kiwi Pilot .Actually gives you some idea of ' visualiseation ' of the airflow over one of these , as it gets a bit out of whack here & there .
Did a Mercury Tiger Moth from kit that WON Junior Scale at the N.Z. Nats . ( It was The Only Entry LL~ LL~ )( said in Mag " It Flew Well " DONT BELIVE ALL YOU READ . Bloody Apalling .
UNTILL I put a OS 10 in it & a BellCrank & Elevators .
Demo at the Primary School , on a r idge so often a breeze there , Had Me Trying a Loop then A Lap Inverted . No Bother . with the free flight declanage & Flatt Bottomed wings . %^@
Engine Cut upwind , and as the fields were manicured had a half lap run to downwind , stop , and drop the tail . Another Total Fluke. unpublished this time . LL~ S?P
Have a plan & Two OS 10s. Only one should be necessary . ;D
Old Tyme , Theres a De H 82 with big elevators ( as they did then ) & NO Flaps , But A symetrical Airfoil about almost 3/4 I think ish thick . Maybe for a .15 ?? , will tryn digit outn getta picture , for here . Of The Plan. and Date .
as they say its a ' Stunt ' plane . Model Aircraft or Aeromodeller . 1954 or 6 maybe .
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One thing I was really wanting from this post was some idea of what percentage of airfoil " cord vs. camber" for a great flying biplane. I would have thought a thinner airfoil would be needed, but I see many of the suggested designs have a fairly thick wing. What's up with this? Regards, Blaine
I agree with you - I would make the airfoil thinner on a biplane. The only danger is making it too sharp, otherwise, I think efforts to reduce the parasitic drag are to the better.
Brett
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As I understand things, wing alignment is pretty critical on a bipe. I don't know what the .38 Special plans and instructions say in that respect, and have not read any of the mentioned construction articles in a LONG time. More or less make bottom wing at 0 degrees and top wing just a hair negative, or something like that? If I build a bipe soon it will be the .38 Special 'cause I got the kit, then do the two SIG biplanes just for nostalgia reasons. I figure anything I can learn out of this will help the SIG models.
HAPPY HOLIDAYS!
Dan McEntee
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Tutae Wera .
(http://www.franklinairshow.com/img/Waco-Photo.jpg)
Dosnt Censor period grammer , when you put it in Maori . ;D
http://www.venturapublications.com/store/index.php?main_page=product_info&products_id=257
A Battle of Britain Spitfire called that , too .
A WACO . gee Wilikers , theyre still in Buisness . http://www.wacoaircraft.com/waco-ymf-5 Bespoke Aeroplanes Even , Airplans to some . S?P
the fin motif appears synomonous with my Avatar , :-X .
Been plenty of kits & plans for em , One a 72 in R C , as a base ?? H^^
(http://1941waco.com/wp-content/uploads/2014/04/016-Full-pre-cover-assembly.jpg)
http://eaaforums.org/showthread.php?4935-1941-Waco-UPF-7
(http://1941waco.com/wp-content/uploads/2014/04/016a.jpg)
RIGHTIO , if you Get to Work , you could haver it done in a week or two . LL~ ( Left the inadvertant R in , as seems more Apppropriate .)
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Do tandem wing models qualify?
There are some interesting designs if they do!
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Been plenty of kits & plans for em , One a 72 in R C , as a base ?? Hoff
This Waco was a Pica kit, I think 1/7 scale at possibly 55", I'd have to measure it.
Was my R/C flagship. LL~
The model is so old, the iron on covering is falling apart. I'll look for another OS 90 which is what I had in it, then I can do a recover and add some detail.
Nice for scale and T&G's but the airfoil isn't symmetrical.
Charles
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I'm more interested in traditional or. "semi-scale" biplane. Thanks for the question!
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Apparently theres a Dave Platt & a PICO Kit for the YMF3/5 at 60 in. span , and a PICO at 72 span . Presumably the one I saw in NZ with White red stripe picture on box . Not that its a control line stunt kit . But perhaps something to start butchering %^@ to taste , or scrible over the R C Scale drg.
(https://static.rcgroups.net/forums/attachments/1/5/0/7/1/a4865001-188-picaF6554.jpg)
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No , but thank you for wondering! Looking for a traditional, or " semi- scale" bipe. Regards, Blaine
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Bart Kaplinski did pretty well with his Fleet biplane flying in Old Time at VSC.
Oh the other hand, Bart could fly his garage door through a better pattern than most of us mere mortals! Probably power it with twin Fox .59s so that it could be heard coast to coast.
Ted
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This is the best bipe stunter I have ever watched. Mr,T's TIGHT, powered by Saito 82(?). He got 10th place at '11 Japan Nats. Not only flew very well but also was very beautiful and won the most beautiful model of the year prize. No plan, sorry.
Aki
WOW!!
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I'm more interested in traditional or. "semi-scale" biplane.
More Assine drivle . :o
The Renowned Snyder Mc Ready . ???
(http://www.aerofiles.com/snyder-mac.jpg)
Plan for a rubber band job is in same A. M. as Al Rabes p 51 series Mag . 78 ??
Theres a simlar Square rigged WW1 ? 1916 ? Mexican fighter , hispano suiza SQUARE RIGGED snaffall stagger straight linejob .Penut scale Plan in one American Mag .
Both of these'd make simple light semi scale , near scale , or just Purloin the look type LIGHT WEIGHT ships , if you made the light weight . stick & tissue ,
id be inclined to Wire Brace em with say .015 wire to take the flying & landing ( inverted ) Loads , Spruce 1/2 x 1/8 vertical for the wing spars , or suchlike .
(https://s-media-cache-ak0.pinimg.com/564x/08/59/21/085921c8418f103a597f0d5964e76e10.jpg)
Maybe this is something to do with it , Two seater Version ? .
(https://s-media-cache-ak0.pinimg.com/564x/b4/ec/c7/b4ecc7122f775dca3851ac382c7351e1.jpg)
For Real Men a SBC-3 Helldiver , Brent Williams wing & moments ??
(http://www.airwar.ru/image/idop/sww2/sbc/sbc-5.jpg)
Been Kaz's F6 & some F4s , Grumman Iron works rolled Tube Fuselage , moulded . good to have the retracts . ;D LL~
Im sure someones done a profile of this , cool looking aeroplane .
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"More or less make bottom wing at 0 degrees and top wing just a hair negative" - from Dan's post above
I have read this also, but don't know where. Is this primarily for full scale planes and RC models where upright flight handling, stalling, and landing manners are most important? Would this apply or be relevant to a CL airplane?
Does the hair negative incidence for the top wing translate to just don't have it positive?
I am building a 38Spl and have the wings done and the fuse almost done. I have been planning on aligning everything at zero - zero. Now I am wondering...
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"More or less make bottom wing at 0 degrees and top wing just a hair negative" - from Dan's post above
I have read this also, but don't know where. Is this primarily for full scale planes and RC models where upright flight handling, stalling, and landing manners are most important? Would this apply or be relevant to a CL airplane?
Does the hair negative incidence for the top wing translate to just don't have it positive?
I am building a 38Spl and have the wings done and the fuse almost done. I have been planning on aligning everything at zero - zero. Now I am wondering...
Hi Steve;
My .38 Special kit is at the bottom of a BIG stack of kits and hard to reach. What does the plan and instruction say about jigging up the wings when attaching to the fuselage. May have to do a search and see what John Miller has to say on the subject, or see what others may share. I'm really curious what the Brodak book and plans say, given that the examples I have seen fly here seem to fly really well, even in the hands of beginner and intermediate class type pilots. What ever the plans say or the book says must be good.
Type at you later,
Dan McEntee
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Blaine -
Here are two excellent SH threads on biplane stunters:
http://stunthanger.com/smf/stunt-design/almost-finished-with-it-my-stunt-biplane/
http://stunthanger.com/smf/open-forum/why-no-competitive-biplanes-in-stunt/
I have six posts in the first and five posts in the second. For clarity and brevity, I recommend the second URL, but most aspects are discussed in each, with many other contributions by some of the better sources on the internet. My main points are that biplanes have theoretical maximum efficiencies of 200% those of "equivalent" monoplane wings, but more practical ones between 100% and 137%, except for box wings that can go as high as 147%. What brings them down about even to monoplanes is aspect ratios and applicable Reynolds Numbers.
I recommend these posts, plus some in the SSW Forum archives. Searches here work well too.
SK
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"More or less make bottom wing at 0 degrees and top wing just a hair negative" - from Dan's post above
I have read this also, but don't know where. Is this primarily for full scale planes and RC models where upright flight handling, stalling, and landing manners are most important? Would this apply or be relevant to a CL airplane?
Does the hair negative incidence for the top wing translate to just don't have it positive?
I am building a 38Spl and have the wings done and the fuse almost done. I have been planning on aligning everything at zero - zero. Now I am wondering...
The negative incidence concept has been mentioned in earlier posts in this thread above.
Hal deBolt wrote about it in his article on the deBolt Bipe in the July 83 issue of Model Builder. The airplane dates back to the 40's with flat bottom airfoil. Remember, this article discusses his thinking in the design evolution of that airplane over 40 years prior to his MB article. In his article, he wrote:
"The proper use of decalage can enhance longitudinal stability. The law ways that if you fly the forward wing at a higher angle of attack than the aft wing, then the forward wing will stall first, thus the forward wing will lose lift while the aft wing maintains it. In that case the center of lift automatically moves rearward tending to pivot the nose downward at approximately the center of gravity, or control pivot in this case once the nose comes down, the forward wing gets it lift back and you are flying safely once more. ... The Bipe uses two degrees of negative incidence in the rear wing for this purpose."
Now, fast forward to the Dutchess/Dancing Girl/Tiger Rag/Cavalier series of biplanes by Peter Miller. (Dutchess - Aeromodeller, Aug 74; Dancing Girl - Model Airplane News, Feb, 75; Tiger Rag - Model Aviation, Mar 82; Cavalier - Flying Models, Nov, 99) These four designs represent a even longer series of airplanes by Miller. In his two part 1974 article on the Dutchess, Miller does not mention any wing decalage. Then, with his 1975 article on the Dancing Girl, Miller mentions stability problems with all of his previous biplane attempts. He then references the old deBolt Bipe article with "1o negative incidence on the top wing, so I tried it and the stability problem vanished..." In this article, Miller then explains the evolution from 10% to 18% airfoils with the Cavalier and "Instant success, Cavalier flew the full schedule." In his 1982 article on the Tiger Rag, Miller writes "The layout... seems to be the optimum for this type of model: thick wing section, equal area for both wings (with the thrust line passing just above the center line of the gap between the wings), large stabilizer and elevator with big control deflections -- and no flaps. Light weight is also a critical factor. ... Care must be taken with the lower wing seat to ensure that it sits a 0 degrees incidence." The plans for his Tiger Rag show the top wing to be mounted with "-1o incidence". Then, in his 1999 Flying Models article on the Cavalier, he summarizes the series by saying his Cavalier proved he had hit the right formula with the 18% section and 1o negative incidence on the top wing. His article mentions the "vital 1o negative incidence" in the top wing.
TROSTLE NOTES:
1. I am not sure of the accuracy of the information deBolt provided in his 1983 Model Builder article regarding the negative incidence on the bottom wing. Somehow, deBolt's findings from the 40's was later translated by Miller and others that it is the top wing that is to have negative incidence. (These later developments were prior to the Model Builder deBolt article.) I would certainly go on the series of articles and plans by Miller and use the 1o negative incidence on the TOP wing.
2. There are several "successful" biplane designs that have been mentioned in this thread, like the Hutchinson Stearman (based on the J.C. Yates design which is very close to scale), Sheeks' Staggerwing (semi-scale), Jim Hunt's TravelAir (scale), Hinton's "59er", Claus Maikis' Duetto, Don Yearout's Biceps, the several Italian and Japanese designs (if plans are available) and on and on. I would recommend as a starting point to use the Miller Cavalier. It is the result of a long evolution of CL biplane stunters. If not just build to his plans, then at least use his layout for proportions, airfoil, and the negative incidence on the top wing. You will also need lightness and power.
Keith
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Dan , Serge, Keith,
Thank you for your input and sharing your knowledge on the top wing negative incidence part of this thread.
The plans that came with the Brodak 38 Special kit are hand drawn but extending the chord lines of both wings shows they are clearly drawn to be parallel (zero - zero).
I will shoot for zero - zero, make sure I don't get positive in the top wing, and if it comes out 1 degree negative on top, I will sleep soundly.
If the top wing turns out to be 1/2 degree negative, I will say I used extensive jigging to attain that. Heeee.
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Dan , Serge, Keith,
Thank you for your input and sharing your knowledge on the top wing negative incidence part of this thread.
The plans that came with the Brodak 38 Special kit are hand drawn but extending the chord lines of both wings shows they are clearly drawn to be parallel (zero - zero).
I will shoot for zero - zero, make sure I don't get positive in the top wing, and if it comes out 1 degree negative on top, I will sleep soundly.
If the top wing turns out to be 1/2 degree negative, I will say I used extensive jigging to attain that. Heeee.
Barring any specific information applicable to CL Stunt, I would certainly start there. I can see some reason, not very good, to move them both (one positive and one negative, I won't venture a guess as which one goes which way) but in general I would expect them to want to be 0-0.
Brett
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It should be fairly simple to design the top wing so you can set it at zero and then adjust it to -1 degree. Would make for an interesting comparison. H^^
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I had the same thought myself. Would make for an interesting experiment! Thanks.
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It should be fairly simple to design the top wing so you can set it at zero and then adjust it to -1 degree. Would make for an interesting comparison. H^^
The basic idea that Glenn proposes here is good. However, most of the literature I have seen suggests it best to have the bottom wing at -1o. (See the comments by Peter Miller above with his years of experimenting with biplanes.) If the top wing is made adjustable, then why not make it adjustable through a range of say -2o to +2o? That would mean the angular difference range of the bottom wing would be from +2o to -2o respectively. Would save having to reinvent the idea of what works best instead of building a whole series of biplanes which has already been done. From the literature, the difference in wing incidence from one wing to the other appears to help make the airplane more stable. (In Miller's case above, he found 1o negative incidence in the top wing to be advantageous.) So then, the question comes up about what to do with the thrust line. I would think that thrust line sensitivity would be small if not negligible if the angular differences of the two wings are in the range of say +/- 1o or even +/- 2o and would have little sensitivity. So for this exercise, just live with the thrust line being constant. If, on the other hand you build a biplane with an upright (or inverted) engine, you would also be able to change the thrust line as well.
Structurally, an adjustable incidence top wing should not be too difficult. Just need to be careful that the change in incidence is locked in and constant at each of the wing attach points.
Good luck.
Keith
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All I know is my 38 Special flies mucho better than I do. It is built box stock wit OS 40 for power. Need to dust it off again like so many of my other planes. H^^
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Do I sense interest in a Biplane event??????
Doc Holiday reports that he likes my Vagabond.
As originally designed the span is 34" to do Slob type flying but with a better glide and an aluminum landing gear to correct tendencies for the gear bend back and hit the lower wing.
Increase the span by one rib bay at each tip and the span becomes 39.25 " and would be good for a .4o or .46 engine.
Increase the span two rib bays and the span will almost 46" good for a .56 or .60 engine.
The larger version might also benefit from a longer tail moment. Increase the motor mount width to suit the engine.
http://stunthanger.com/smf/open-forum/vagabond/?action=dlattach;attach=237694;image
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(http://www.modelenginenews.org/images/gpd/bi-slob_plan.jpg)
LL~ LL~ LL~ LL~ LL~ LL~ LL~
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Matt.
Look in the BiSlob title block you will see that I drew the plans (And wrote the article.
The Vagabond is a NEW design using the Hobo ribs. ( I also designed the Hobo)
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And they both do what they are supposed to do. Thanks to Tom. H^^
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He he, check out what the wing incidence is for a Pitts or a Christen Eagle. Not an early Pitts, but say an S1S.
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Do I sense interest in a Biplane event??????
Doc Holiday reports that he likes my Vagabond.
As originally designed the span is 34" to do Slob type flying but with a better glide and an aluminum landing gear to correct tendencies for the gear bend back and hit the lower wing.
Increase the span by one rib bay at each tip and the span becomes 39.25 " and would be good for a .4o or .46 engine.
Increase the span two rib bays and the span will almost 46" good for a .56 or .60 engine.
The larger version might also benefit from a longer tail moment. Increase the motor mount width to suit the engine.
http://stunthanger.com/smf/open-forum/vagabond/?action=dlattach;attach=237694;image
Hey Tom: Liking the looks of this Vagabond. I would build it as a sport stunter with normal control throws and thrust offset.
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Allan,
I wish I had the time to build several versions of the Vagabond. But, my efforts now are to build a new design Pampa ship that I call "Ragtime" It will be my first electric and is very different from everything that is out there at this time.
The .40-.46 size Vagabond with the added rib bay will fly great, with normal engine off set. I can get plans to you for cost of repro and shipping.
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They look good planes . The Bi Slob must be ideal for a novice getting through the pattern ,, with its ' all the time in the world ' for corrections , and tight turns for avoidance of Terra Firma .
How does the Vagabond go for that , with the straighter thrust line ? looks like a straightforward build , youd be in the air before NEXT Christmass ! . 8)
Perhaps this ones not ideal , :-\
(http://www.abc.net.au/news/image/7418126-3x2-700x467.jpg)
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The Vagabond is very easy to build. Tom picked the slowest builder to build one.
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The Bi Slob must be ideal for a novice getting through the pattern ,, with its ' all the time in the world ' for corrections , and tight turns for avoidance of Terra Firma .
The BiSlob is the worst possible stunt trainer, it teaches you entirely uncompetitive approaches and does absolutely nothing "honestly".
Brett
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it teaches you entirely uncompetitive approaches and does absolutely nothing "honestly".
%^@ %^@
ANYBODY"D THINK IT WORKED FOR THE GOVERNMENT !
LL~ LL~
Was thinking more ' The Ab Initio ' trainer . For someone whos getting along ok with level flight . The way they trundle round , anybody with two brain cells should be able to get along fine TRYING manouvres .
just to get the reflex/ sequence in order . Rather than any ' geometric niceties . They can come later . My Views someone who can position the plane anywhere at will , can cope with ' the pattern '
But not neccesarilly Visa Versa .
A Competant * plane in resonable air , having the ' CONTROL ' sequeces in the right order , ( Memory Recall - 1/2 Doz min for Memory . )Like a Motorcycle Track , and your on you way , as long as you dont get distracted .
( * Aeroplane with NO Line Tension ' irregularities ' . )
I should think a Bi Slob Pilot being abused by a proficent instructor could manadge ALL the FAI Schedule Manovres , If ( definately ) NOT in the Correct Size Height etc , at least in a semblance of the correct shape .
Thus Learned , he could then proceed to open up to the correct proportins & geometry , at a later stage. Another Chapter in His/ Her Progress , No Doubt .
BUT The THING would get thru the shape sequences , at altitude , with time to spare for thought & observation .
Just My Humble Opinion .
A Pommy Profile Peacemaker'd do it to , on 60s . But They BREAK if you bounce them, And it'd be inevitable .
A Bi Slob it'd be inevitable That Youd Crack Up / Fall Over Laughing . Rather than the Aeroplane doing so . Its Ability to ' Hang on a Line ( Wire ) being one necesity , For How to Ham Fist a Stunt Patern .
https://www.youtube.com/watch?v=F49v_p7FwcQ
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My search online revealed that a Pitts S1S has a upper wing incidence of 1 and 1/2 degrees with the lower wing at 0"/0" degrees. Not sure if this has any meaning for our models? Regards to all, Blaine
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Will the 38 Special make a nice square corner?
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Maybe something along these lines?
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Will the 38 Special make a nice square corner?
Mine makes a good square corner. The last times I flew it made my patterns look good. H^^