Need info on Halberstadt fighters

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Trev -> Need info on Halberstadt fighters (10/24/2004 1:05 PM)
I'm trying to gather some info on the Halberstadt D- series (II, III, IV) single seat fighters. Ever since playing Red Baron I've had my eye on the Halberstadt D.II and hope one day to build a scale or semi-scale model. The full flying/fully deflecting tail surfaces reminiscent of the Fokker Eindecker I find particularly appealing. Which variant I'll build will mostly depend on the available information. One excellent doccumentation source is the windsock datafile (Halberstadt fighters) which has some decent 3-views. However, it caters more to the needs & requirements of plastic modelers and lacks some of the details specifically required for rc-modelling. As such I don't have any good illustrations of the airfoils or values for wing incidences used on these fighters. Would anyone know where I can look for them?? I'm aware that such details for any of these rarely modelled ww1 A/C are probably hard to come by so I reckon it might also be possible to adopt the airfoil and incidences of more common types such as the albatross (which has a similar configuration). Hence my next request: anyone have any airfoils/ incidences for albatross fighters? (proctor kit for instance) [:D] help is much appreciated! cheers, Trev

The PIPE -> There's DROOPY trailing edges, too...!!! (10/24/2004 4:09 PM)
Dear Trev: The PIPE here yet AGAIN...and I've got one of those Halberstadt D-series Datafile SPECIALS, too...! There WAS a set of USA done scale drawings-which INCLUDE scale STRUCTURES-of the Halberstadt D II that appeared VERY recently in Leo Opdycke's WW I AERO magazine...that were done in 1967, and were provided by TOM POLAPINK, the new "Models" column editor at Leo's quarterly!!! I've just checked my hard drive, and it looks like I haven't YET scanned them into my hard drive...would you like a copy of them sent to you via Email, as JPEGs, when I CAN get them scanned...which COULD very well be THIS weekend ??? I'd still use the Windsock drawings as the MAIN source for dimensions, scale shapes and locations for everything...but those 1967 era scale drawings, done WAY before ANYONE thought of drafting up model construction plans on CAD software...DO seem to have VERY VALUABLE scale STRUCTURAL info on them, and I'd like to send you THOSE, as well, IF you'd like! Where it DOES seem like you've got the Datafile Special on the Halberstadts, have you noticed the DROOPY trailing edges on just about ALL the Halberstadt D-series aircraft yet, that are shown in the photos in that Datafile??? I'm in a REAL DILEMMA on whether to replicate the "droop" of those trailing edges on an RC MODEL of one, since I'd bet that the "trailing edge DROOP" would have "flattened out" with the plane IN FLIGHT...what do YOU think??? Anyway, I've ALSO got the Spandau MG "Mini-Datafile" which ALSO shows the TRUE appearance of the earlier Spandau MG's rear "mechanics"...they had a main body that was FULLY RECTANGULAR in the early, Fokker E-series and Halberstadt fighter planes, WITHOUT the "cutdown top profile" the LATER ones had by the time MvR's preferred Fokker Dr I showed up...I'll be doing up a set of CAD drawings up of one of the earlier Spandaus for myself AND other modelers to use for scratchbuilding, as well for the earliest "überschlissig" Spandaus...which had SO MANY cooling slots in their air cooling jackets that THOSE earliest-of-all-Spandaus had, that they ended up just being TOO SHAKY in structural rigidity to really make them useful when fired. PLease let me know IF you'd like those hand-done scale drawings from Leo's magazine...hope to hear from you REAL soon!!! Yours Sincerely, The PIPE! ;)

Trev -> RE: There's DROOPY trailing edges, too...!!! (10/24/2004 5:17 PM)
Pipe, I was hoping someone like youself would stumble across this thread All I can say is that ANY images you'd care to send me would be VERY welcome! PARTICULARLY "those hand-done scale drawings from Leo's magazine" So the answer to your question would be an emphatic YES PLEASE![:D] I'm actually most biased towards the D.II as it has more of that early WW1-flair. While I don't actually have the datafile special in my hands (recently ordered and mistakenly addressed to my parents) I'd asked my dad to leaf through it and he confirmed the lack of any detail airfoil drawings. The small 3-view caption of my last post was in fact scanned from that datafile. I can see your point about the drooping TE, I really wouldn't have a clue about how to replicate it...especially as the wing chord seems to be constant. Any in-flight material or structural dynamics resulting from this droop are even more daunting in the context of a scale construction. I for my part would settle with a non-droop TE where all ribs terminate on the same plane. Quite frankly I just wouldn't know how to build the wing strait otherwise. I suppose a seasoned scale builder (such as youself I'd reckon) could achieve it though, in any case this would set a model apart from the rest! (although I've yet to come across an rc model of the halberstadt D.II) Btw, on several previous occasions you had mentioned that you were either constructing or about to begin construction of a proctor E.III, if I'm not mistaken with carbon rod fuse stringers? I sure would love to see any progress on that!

abufletcher -> RE: There's DROOPY trailing edges, too...!!! (10/25/2004 2:45 AM)
Trev, I also looked hard at the Halberstadt DII. I particularly like the funky rudder. It's sort of like a transitional design between the EIII's full flying rudder and the later designs with a vertical fin. On the trailing edge "droop" (I can't quite make out what this is in the 3-view) I'd want to consider this carefully as this seems to be how a lot of the WWI, thin airfoil aircraft built in washout. For example on the 2-seaters I'm looking at many and washout built into the ailerons which gives the wings an attractive bird-like quality. I'm not sure how I'd go about building an aileron with washout but I'm sure it could be done. Pipe, I'd also be interested in seeing those structural drawings. While I'm not specifically planning on building one, I find that what I learn about how any of these early birds were really built is applicable to others. Particularly from one German manufacturer to another. Trev, I'll try to scan in the airfoils from some of my Albatros 3-views. This is one area that I might be willing to fudge a little on a scale RC model. All thin wing airfoils are going to be pretty similar so if there is one that looks like it would be stronger I'd go with that. My own modeling is completely on hold (beyond repairs on my current ARF after a day at the field) until I can get back to the US.

Trev -> RE: There's DROOPY trailing edges, too...!!! (10/25/2004 7:53 PM)
Abu, trust me I know how unnerving the lack of modelling activity can be away from home. In my case the distance is not as severe, just 300 km or so (I actually live more to the south in Hessen where ppl have a very slurred, easy-going accent compared the "high german" of lower saxony) but all I can do is wait for those rare intermittent weekends when I return home and manage to achieve some modest progress. At least that leaves plenty of time for research[:D] Modelling the Halberstadt D.II has several benefits from my point of view (TE droop aside!), Early german WWI biplane flair, large wing area = floater, 8 struts (wing panels could be pre-rigged and simply plugged into fus), fuse similar to but not nearly as complicated to build as that of the albatross, longer nose moment than most rotary-powered A/C, and of course the cool full-flying empennage. And contrary to the ubiquitous Albatross it seems to be a very rare subject for rc-modelling. Though I have to admit the scales haven't yet tipped entirely in favor of the D.II, I'm still very hard pressed to consider the Nieuport 10 or 12 2-seater for my next project, simply love the compact dimensions and sesquiplane configuration, and the typical large rotary engine cowl. Just to pick up on the TE-droop issue, from the Halb D.II images I've managed to scour off the web (must get my parents to send me that datafile!) it is indeed quite evident. wintip and wingroot appear to have the same diheadral...with the lower wing the centre section droops most, on the upper the droop is less where the aileron begins. To replicate it in a model I'd imagine one could use ribs with varying TE-curvature Would be interesting to know the aerodynamic effects the designers hoped for/ to me it just looks mostly like shoddy workmanship.[:)] I've also included a sort of generic albatross airfoil I've found on the web. Might use something like that if I can't find an authentic Halberstadt one. Would gladly accept any additional airfoils though, so if yer could scan them...[:D]

MajorTomski -> RE: There's DROOPY trailing edges, too...!!! (10/25/2004 9:11 PM)
Guy Fawcett (gfawcett@NRCan.gc.ca) over on the WW-I modeling list did one a few years ago. http://www.wwi-models.org/Images/Fawcett/index.html I think it was published in a US magazine.

MajorTomski -> RE: Need info on Halberstadt fighters (10/26/2004 5:24 AM)
there is also a complete thread build over on ezone http://www.rcgroups.com/forums/showthread.php?t=154498&highlight=Halberstadt hth tom

Trev -> RE: Need info on Halberstadt fighters (10/26/2004 8:52 AM)
Tom thanks for the links, those are two very nicely built and finished models! My compliments to the builder & designer. Very scale for that size./ Only slight concession appears to be the flat-bottom airfoil, in favor of performance I gather. The building thread also gives some good insight into construction aspects. I'm really beginning to like the rustic looks of this A/C. The nose area doesn't appear to have nearly as many compound curves as for instance the albatross. Mypreferred scale would be slightly larger at 1/5 and 4S power instead of electric. A rough estimate would put that at approx 175 cm span and a weight range of 3-4 kg. I'd also try and go with mostly spruce & ply construction, especially on the fuse stringers. Might consider building a small balsa one first as a prototype though[:D]

The PIPE -> RE: Need info on Halberstadt fighters (10/31/2004 7:19 PM)
Dear Trev: The PIPE here yet AGAIN...and early on Saturday morning over here in New England, I sent BOTH Abufletcher AND YOURSELF the ZIP compressed file with ALL SIX Halberstadt D II drawings from the pages of the May 2004 issue of Leo Opdycke's WW I AERO quarterly magazine...!!! It's an attachment named "Leo-Drawings.zip"...and I INCLUDED the link for the GERMAN version of WinZIP in the text of that Email, so you could decompress those drawing files for your needs...that's IF you haven't installed the downloadable shareware version of WinZIP as yet on your PC!!! PLEASE let me know if you got the drawings all right...I'll be waiting for your reply...! Yours Sincerely, The PIPE! ;)

pjwright -> RE: Need info on Halberstadt fighters (11/10/2004 9:19 PM)
As I recall, the Ebay seller, "uncle-willies", has a Halberstadt plan in the 80"+ wingspan range that he occasionally offers. You might do a search by that name, and then do an "ask seller" to see if that's the case... http://search.ebay.com/_W0QQgotopageZ1QQsassZuncleQ2dwilliesQQsorecordsperpageZ50QQsosortorderZ1QQsosortpropertyZ1 Looks like a great project! [And Pipe-man, I'd luv to get a set of Mr. Polapink's drawings, if you're of a mind...] ;-) pj

lakefish4 -> RE: Need info on Halberstadt fighters (11/12/2004 2:20 AM)
Hey Trev, Ever tap the Smithsonian Archives??? They have been a real help on several scratch scale WWI projects of mine over the years. Might be suprised! If interested in emailing them just drop me an EMAIL - lakefish4@worldnet.att.net and I will give you their address. They usually send what they have snail mail and currently in about three weeks or less. I am presently awaiting a good three view of the 1933 Heinkel HE-51 from which to scratch it. First bipe I will scratch not in the teens or twenties and will fly pontoons and wheel pants as did the original. My best! Al

Sarges_heroes2003 -> RE: Need info on Halberstadt fighters (11/16/2004 1:47 AM)
hey, what is that aircraft in your avatar?? it looks like some thing out of sky pirates video game.[&:] edit: was directed at pjwright, oopss...

pjwright -> RE: Need info on Halberstadt fighters (11/16/2004 12:46 PM)
It's a Curtiss XP-55 "Ascender", Sarge. The moniker "Ascender" was actually coined by the design team as something like "Asc-ender"...but slightly different. The surviving aircraft is owned by the Smithsonian NASM, and was recently restored by the AirZoo Museum at Kalamazoo, Michigan, where it is on display. Google the aircraft name, and you'll get lots of hits...an interesting concept, as designers tried to push prop-driven technology at the birth of the jet age. Regards, pj

John Taylor -> RE: Need info on Halberstadt fighters (11/25/2004 10:00 PM)
Trev, interesting reading here. I have a book from Hannan's Runway in Magalia,CA. It's on the Halberstadt Fighters covers the D2, D3 D4, D5. My friend and I are building two D2's with a 87" wing and will be powered by a gas engine like the zenoah G23. It's an interesting project that's for sure. The plans were blown up from a 40 size drawings. Hope this helps John Taylor Macedon NY[8D]

Prop Nut -> RE: Need info on Halberstadt fighters (11/28/2004 3:33 PM)
Hey PJWright, the Curtiss XP-55 is a great looking plane, I was there a couple of months ago (before they opened thier new building). If you want pictures of it sometime let me know, I live an hour away from there and am within a mile every few months. Any excuse to go to the Air Zoo is OK with me :D

zoomzoooie -> RE: Need info on Halberstadt fighters (1/6/2005 8:34 AM)
Hi guys, hope I'm not to late to get into this one. I am working on a Halberstadt DII also and need drawings too. The Pipe, I sure wouldn't mind that zip file too :) zoomzoooie@cablerocket.com Speaking of ebay Halb plans, I have that same plan. It's a 1/4 scale Halberstadt Dv. Nice clean simple plan with some good scale info. The Airfoil looks the same as the one Trev posted, which I'm using since it looks close enough and there is not much info on the web for the Halb DII. I have been studying the pics I have gathered for the droop of the trailing edge. I am going to put this droop in mine, but since I have no accurate info on it I have drawn up my rib plans by eye balling the amount of droop in the photos I have. It's harder to describe then to do. I started with the lower wing since it appears to have the most droop. I used 3 degrees of incidence which looks about right. It's not that critical because the Halb DII uses a full flying elevator. It appears that about 25%-26% of the depth of the camber with the airfoil set at 3 degrees is close(see pic). The deepest part of the droop appears to be at rib 4. So, using the root rib #1 set at 3 degrees, ribs #2,#3,#4,#5,#6,#7, will be drooped. Rib 8 will be set the same as the #1 root rib. To get a nice flowing curve use a flexible straight edge fixed at rib #1 and rib #8 and bow it to the new mark on rib #4 and draw your new trailing edge line. Rib 9 will start the reflex with new trailing edge above the 0 degree line about 12%-13% of the camber depth. Shape the wing tip bow following the upper camber of the airfoil and add about 25%-26% of the camber depth above the 0 degree trailing line at about 5/6th of the cord, for your new trailing edge reflex. To draw your new ribs, on the main rib draw a short line at the trailing edge under side and at the leading edge underside. These will be your reference marks. Traced out your new ribs over the main rib by first marking the reference lines then mark the amount of droop from the trailing edge reference line. Start tracing the ribs from the leading edge only to the highest camber, keeping the ends or your lines lined up on the main rib, move the trailing edge down to your new marks and finish tracing the rib. As the droop gets lower you should trace move the rib, trace, move the rib and trace till you have the new trailing edge on your new mark to help keep the proper lines of the rib. You will have to refine your new rib. Once you have all your ribs drawn out, you can mark the ribs for the ailerons. This airfoil is very thin so the ribs should be made of strong material. I am going to laminate mine from 1/32 hard balsa sheet. Oh by the way, my Halb DII is only 1/10 scale with a 34,3/8" wing span. Once I find out how well it will fly with the droop and reflex I want to draw up 1/4 scale plans. There's were all the accurate details I can find will come in handy. Take a look at my drawing to get the idea of how I did this. It's not accurate but gives you the idea. The lines in red will be the new lines to reference for your new drooped ribs. It's all eyeballed from photos so your's might turn out different. ZZ

triflyer -> RE: Need info on Halberstadt fighters (1/7/2005 3:42 AM)
In the early 80's I built two Halberstadt fighters, a DII and a DIIa. I remember having to do extensive research just to come up with any type of drawings or info. I don't think I ever found any drawings that were alike. Some had different nose treatments, strut arrangements, wing tip differences and rudder shapes. Nor could I find a agreement as to which one was which - DI, DII,DIII, or DIV. Very frustrating. Again this was many years ago and research sources such as the internet was not available to confirm information. I wanted to build a Halberstadt that utilized the flying tail and rudder and also used ailerons. I built the DII in 1/6 scale and used a early version of the Saito .45 4C. I incorporated the "droop" as wash-out in the ailerons. This made landings very managable and I could slow the plane down to a crawl without worry of stalling. With a flying stab, incidence was not real critcial. I did have +2 on the top wing with 0 on the bottom(in relationship to the thrust line). At the time I drew and built this plane my scratch building skills and general knowledge was limited. I did not build this plane for show, but wanted a dogfight partner for my Neuport 11. I used a flat bottom airfoil that was equivilent in thickness to the original undercambered airfoil. If you are looking for an exceptional flying WWI example this plane is it. It would not do many aerobatics,just as the original Halberstadt DII, but this is not why we build and fly WWI airplanes. I also built a DIIa which, if my memory serves me right, had a different profiled nose( no spinner) because of a different type of motor, and a different cabane strut arrangement(it did not use the inverted ("V") rear cabane similar to the Neuport 11-27 series. I could be wrong on this, as it was a long time ago. I used a OS.60 4C and it also flew very well. I think that the British magazine, Flying Scale Models, offers 1/5 scale plans. Someone in the States has a full size flying Halberstadt in which I took pictures of at Oshkosh years ago but I believe it may have been a DIII. It had the flying rudder but was a different shape than the DII. I am sorry if any of this info is incorrect, as it has been quite some time since I researched this plane. I will check my files to see if I have any drawings or info left.

zoomzoooie -> RE: Need info on Halberstadt fighters (1/9/2005 12:34 AM)
Triflyer, What is the difference of the DII and DIIa? Can you confirm? There is a lot of contradicting info on the Halberstadt D types on the internet. I don't a copy of the Datafiles Halberstadt fighters yet but I have seen a lot of differences in the photos I have collected and the description of which type they say they are. The differences I have noted from the photos I have: Cabane struts - Early types have double inverted and others have a third inverted strut at the front. Others have 3 vertical cabanes. Upper wings - Early types have straight trailing edges while others have an extented aileron cord and some of those have a taper at the center visiblity cut out. Some of those cut outs have straight lines and others are half round. These all had the trailing edge "droop". The later types had straight ailerons with aerodynamic aileron balances and no trailing edge "droop". Aileron controls -The early types had cables coming for the lower wing to a horizontal aileron control arm. The cables exited the lower wing wide at the spar locations. There are some that the exit points on the lower wing where close together. The later types used torque tubes with control rods coming up near the fuselage. Rudder - They all had full flying rudders. The early types had a sharp radius at the top of the rudder. The later types had a wider radius at the top of the rudder and some had the lower section of the rudder removed to allow a full elevator with out rudder allowance cut aways. Elevator - They all had full flying elevators. The early types had rudder allowance cut aways. The later types had the rudder allowance cut aways filled in. Turlte deck - The early types had 7 stringers with fabric covering running part way to the tail. The later types had a plywood turtle deck that ran all the way back to the tail. These are the ones that had the full elevator, cut away lower rudder and aileron torque tubes. Spinner - I have notice a spinner only on later types with torque tube aileron controls. Engine - 120Hp Mercedes seems to be the most common. From the info and limited pics I have I believe: DII - straight wing trailing edge with "droop". DIIa - extended aileron cord on the same wing and added front cabane strut? DIII- extended aileron cord and taper near center visibility cutaway and vertical cabane struts. DIV - I have no info but I would think that it would be close to the DIII. Maybe the center cutaway was rounded? DV - Straight trailing edge,dynamic aileron balances, rounded visiblity cut away in upper wing. DV later? - reshaped rudder with new strut brace location(some had no struts), full elevator, plywood turtle deck and spinner. The fuselage was of wood frame, plywood and fabric. The cockpit forward had plywood covered sides and deck but I have a pic showing all fabric sides but it also has the 3 vertical cabane struts. The later types had a plywood turtle deck /all plywood? Much of the drawings out there are contradicting, even on the same drawing. I compared the drawing to the pictures to arrive at my conclusions. I don't have accurate measurements but it seems it's agreed that the DII had a 28ft,10in wingspan. All the drawings do not show the trailing edge "droop". I looked over the drawings from The Pipe's zipfile (thanks again). I believe this is a DIII, not a DII as it is labeled. It show 9 turtledeck stringers when there should be 7. ZZ

Trev -> RE: Need info on Halberstadt fighters (1/11/2005 7:28 PM)
WEll a lot has happened since I last visited RCU (last year). Thanks a lot guys for all the info and insight! I'm amazed that such a sparsely doccumented aircraft is actually being (and has been) modeled. Right now I'm also still in the research phase and probably will be for some time to come/ still have my E.III to complete which has mutated into a sort of long-term project (too much university-work). zoomzooie, I'd really like to see any construction pics you might have of your prototype. You seem to have researched very thouroughly a lot of the structual features. I particularly like your solution for incorporating the TE droop, please keep us appraised of any progress you make! Of course anyone else who has either built or is in the process of building halberstadt fighers is more than welcome to post their pics! I find that a lot can be learnt by looking at other modelers' work. In case you haven't already got it, I really recommend the windsock datafile on the halberstadt fighters. The amount of info that can be gleaned from the web is rather weak.. For plans I'll probably using the windsock outlines in combination with the structurally detailed drawings PIPE so kindly provided. The latter actually feature a set of airfoils for upper and lower wing. They appear considerably thicker than that of the 'generic' albatros. This question may seem basic (and maybe better asked at the aerodynamics forum), but how do the wing incidences have to be? Should there be a difference between upper and lower wing, particularly considering the 2 different airfoils? From PIPE's drawings I've also seen that there's about one degrees dihedral/ Is there any wash-out? I keep hearing that incidences are not so crucial with full-flying elevators. As you may guess, I don't have a clue about aerodynamics Trev

zoomzoooie -> RE: Need info on Halberstadt fighters (1/12/2005 11:37 PM)
Trev, I wish I had a digital camera to post pics as I go. As it is I have to use my film camera to take pics so I have to wait till the roll is used up, get them developed and scan them. I will post my build when I have all my pics scanned, which my be sometime in the near future. I have been studying the drawings from The Pipe's zip and have found a few things that may not be accurate. Since it appears to be a DIII not a DII, I have compared the drawings to photos that look the same and noticed these differences. 1. The aileron cables exit points from the lower wing are close together but in photos they are at the front and rear spar locations. I noted the above change in DV types. 2. On sheet B2 the lower wing incidence differs from 3 degrees to 4 degrees within the sheet. 3. The most important error is the way the aileron cables are drawn on sheet B1. The ailerons would not work if they were actually like that. The aileron horizontal control arm is not shown and in its place are common vertical control arms on the ailerons. 4. The wingspan noted on the Sheet B1 is 28 feet even. Almost all written specs I have come across note the wingspan as 28 feet, 10 inches. 5. Sheet B4 shows 9 stringers on the turtle deck not 7 as in photos all though cross section F shows 7. 6. Sheet B3 does not show the trailing edge "droop" So now as you can see I don't know how much accuracy is in the other aspects of these drawings. I don't have the Winsock Datafiles yet, but (lol) knowing me I will find differences with them too. I suppose the best course of action because of limited records, would be to take the details from the drawings and compare them with available photos, using the details that appear to agree with the photos. Such details as incidence is impossible to see in the photos but if they look close enough I guess it would be ok to use them. This is what I have been doing. Having limited records makes scale modeling difficult. Have those records contradict each other makes accuracy very much impossible so what do we do? I love seeing those beautiful scale drawings, but they give a false sense of accuracy. In the photos I have it is impossible to see any dihedral. You can see the washout very noticably in the lower wing. I would assume at the tips it is 0 degrees incidence to the thrust line while the root is 3 degrees. (This is how I will set my wing up). If you use the lesser incidence in the top wing I would still use 0 degrees for the tips. As far as aerodynamics go, the thicker top airfoil will create more lift at the same incidence of the lower wing but will also create more drag. To reduce the amount of drag, less incidence is used. I imagine the reason for the thicker upper airfoil(if this is accurate)though, is for the radiator thickness. I cannot tell the thickness difference in photos but the radiator does not appear to sit as high above the wing as is drawn. Incidence is not so critical in full flying elevators because the elevator can easily be set to the same or aerodynamicly stable position. However incidence does relate directly with the thrust line. If too much or to little incidence is used, as power is increased and decrease it will cause pitching moments to be more or less sensitive. If too much incidence is used then the airfoil may stall out before it can acheive enough lift at a set speed or when enough speed is reached the aircraft will pitch up as speed is increased. There is a limit to how much incidence is acceptable, but with a few degrees is not critical, even in non flying elevators. It all depends on the design of the aircraft and where the thrust line is. Full flying surfaces are more efficient at lower speeds. Setting a trim is easy with our RC servos. The same is true for thrust lines. Stability is the major factor of the correct settings. Take a look at the pic. You can clearly see the washout, trailing edge droop and if you look closely you can see the aileron cables exit at the front and rear spars on the lower wing. Also note the different exhaust that actually appears on most the the pics I have. ZZ

zoomzoooie -> RE: Need info on Halberstadt fighters (1/16/2005 7:17 AM)
One thing I have been thinking about is how they went about getting the trailing edge droop. I thought maybe they might have did it the way I posted earlier but after looking at the pics again I think they might have just curved the rear spar keeping the ribs all the same. It appears in the pics that the airfoil on the lower wing does not change shape but only droops. I think I will do it this way instead. ZZ

abufletcher -> RE: Need info on Halberstadt fighters (1/16/2005 8:10 AM)
I think there is a very real question of whether the droop was actually something "engineered in" or whether it just sort of worked out that way. I can't imagine that the designers actually modified the shape of the ribs to create the droop. It seems far more likely that the droop is somehow a byproduct of some other aspect of the wing construction techniques. It may even be some "trick of the eye" in the photos. In a couple of the photos here it almost looks like a warp in the wing! Keeping in mind that scale modeling is at least partly an artistic enterprise, so it's perfectly fair to build in the droop anyway you like. Good luck getting a scale judge to notice the droop!

zoomzoooie -> RE: Need info on Halberstadt fighters (1/16/2005 11:29 PM)
The droop is most noticable in the lower wing. It appears in all the pics I have, which are at different angles, so I would say the droop is physical. I have not noticed this droop in other WWI type aircraft, so I would say it is engineered into the wing. I don't think it just worked out that way. It does appear at first glance that the wing is warped. The only other type that I know of that made use of different rib shapes was the Taube series. The question is: how is it done? :By shape of the rib or warping the rear spar? After thinking about the warped spar idea, I don't think this is how it was done. If you warped the rear spar you would see a warp in the leading edge. There is none so it must have been done by the shape of the ribs. Also if it was done by warping the spar the upper wing would be effected by the warp so it would be hard to keep the warp in the wings other than the by the flying wires and strut lengths. As to the function on this droop, I would say it would be to increase lift at the slower speeds the Halb flies. The wing tip reflex is increased to keep the wing tips from stalling at these slower speeds, which pronounces the appearance of the droop and makes the wing look warped. I think the droop would be quite noticable by judges or anyone else but that is not why I want it there. It is matter of self content I suppose. As to getting it accurate with such limited info, artistic enterprise is allowed. Maybe I'm being to picky but it's what I like. Just hoping someone else will join in with more info to add. Check out the other pics I posted. ZZ

abufletcher -> RE: Need info on Halberstadt fighters (1/17/2005 2:03 AM)
You're right. It's there fore sure -- whatever "it" is! What completely dumbfounds me is that for all the world the lower wing (in particular) looks like it has a curved TE yet all the 3-views show it to be straight. If I had to guess at a function, I say washout for stability. In the photo you posted with the rear view it looks like the top wing also shows the droop. It would be interesting to know how flexible the wing is and whether as the Pipe suggust the droop might alter in flight -- like the flex in a 747 jet's wing. Given how thing these early wings were and the usual forward positioning of the spars in many German aircraft, I'd guess that the rear third of the wing would be fairly flexible. I really wonder whether even the covering process itself could have pulled (intentionaly or not) the wing into this shape. I'm generally of the mind that everything that we see in an aircraft has been engineered in for a purpose, but in discussions (on the rationale behind the curvature on the rear lower wing edge of several German planes) several voiced the opinion that aircraft design at this early stage was still a matter of trial and error and that even aesthetics played a roll. Anyway, if it were me modeling this, I'd also want to model in the droop, as you say just for self-satisfaction, and the challenge would be to create what looks like a variable degree of droop (creating the impression of a curved TE from certain angles and yet still maintain a straight TE as seen from above. Your ideas about modifying the rib tips looks like the best bet, though you'd have to be extremely precise in the cutting and covering. I love a good mystery!!!

zoomzoooie -> RE: Need info on Halberstadt fighters (1/17/2005 6:27 AM)
All drawings I have seen do not show the droop in the trailing edge. It's funny though if you look at the lower wing it looks like the trailing edge is curved across from the root to the tip, specially in the shot from the rear. But it's not. I am wondering though where is the sources for the drawings that are out there? I wondered the same about the flexibility of the rear part of the wing too. With such a thin wing I would also think that there would be some flexing, although I think the covering would inhibit flexing. If too much flexing went on the covering would most likely tear on the bottom of the wing. The Albatros types had an even thinner wing airfoil and I don't think their wings had any flex. One thing I came across was early Fokker D7 top wing center section trailing edges were weak and broke away in flight. This might have had to do with poor craftsmanship though. I think if they would have to have made the rear of the Halb wing strong enough to keep this from happening, most flexing would not be present. I agree with the early experimentation in design. I think the forward positioning of rear spars had to do with the thin airfoil. The spars would had to have been made thick enough to take the stress. Any thinner and they would not be able to so had to be postioned forward. I think what they learned back then is more than we give them credit for. For example the use of full flying surfaces were more effective at slow speeds. Many of the design features do have a purpose and aesthetics is probably one of them. It's just hard to figure some of the features out without actually building them. The art of wood working engineering and techniques they used is mostly lost today. I'm almost finished making templates for the wing ribs. The first set I made were too thin of an airfoil so I had to start again. I decided to go with the airfoil from The Pipe's drawings. For thin airfoil ribs, one way to make them strong is to laminate two balsa sheets together and cut the ribs. I did this with 1/32" hard balsa to make 1/16" and it was extremely strong even with 1/4" rib height after the rear spar. Once I get my ribs cut and start fitting them to the spars I will see how well this will work. My tip bows will have the correct shape as in the pics and will be laminated too. I'll try to build the washout ing the wing but with solid spars it might not stay so it might have to be kept with the covering. I'll post the results. In a large model the spars can be built with a top and bottom and sheer webbed, that should keep the washout. Covering will be the hardest to do because you have an under cambered wing and you have to start the covering on the bottom. I'll have to make jigs to set the wing in upside down to keep the alignment while covering the bottom. I wish I could get pics up but they will have to wait. I'm really anxious to see how it will fly though. Yes it's a mystery all right. [:-] ZZ

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