View source for Lippisch Delta IV

{{short description|1936 experimental aircraft}}
{{More citations needed|date=December 2009}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
  |name = DFS 39 
  |image = Lippisch DFS-39.jpg
  |type = Experimental
  |manufacturer = [[Deutsche Forschungsanstalt für Segelflug]]
  |designer = [[Alexander Lippisch]]
  |first_flight = 1936
  |introduction = 
  |retired =
  |status =
  |primary_user = 
  |more_users = 
  |produced = 
  |number_built = 1
  |unit cost = 
  |developed_from = [[Fieseler F 3]]
  |variants = [[DFS 40]]
}}
[[Alexander Lippisch]]'s '''Delta IV''' was a continuation of his work on [[delta wing]] designs pioneered in his [[Lippisch Delta I|Delta I]], [[Lippisch Delta II|Delta II]] and [[Lippisch Delta III|Delta III]] aircraft.

==Design and development==
===Fieseler F 3 ''Wespe''===
The project began with an order from [[Gerhard Fieseler]] for a design that [[Fieseler|his company]] could build for him to fly in the 1932 [[Europarundflug]] air rally. The result was a highly unorthodox design, sporting large delta wings, [[canard (aeronautics)|canard]]s, and an engine and propeller mounted in both the nose and tail of the plane.

Fieseler built this design as the [[Fieseler F 3|F 3 ''Wespe'']] ("Wasp"), but it proved highly unstable, causing Fieseler to crash it on his first flight. Further refinements were unable to correct these deficiencies, and after one final crash, Fieseler abandoned the aircraft.

===DFS 39===
Lippisch continued to believe that the problems were surmountable, and found an ally in Professor [[Walter Georgii]] of the DFS (''[[Deutsche Forschungsanstalt für Segelflug]]'' – German Research Institute for Sailplane Flight). Georgii secured funding from the RLM (''[[Reichsluftfahrtministerium]]'' – Reich Air Ministry) to purchase the aircraft from Fieseler and work on perfecting it. At the DFS, Lippisch rebuilt the aircraft, removing the canards and the rear engine and renaming it the '''Delta IVa'''.

Although this flew much better than its predecessor, it was still involved in a very serious crash which led to an investigation of Lippisch's endeavours. The RLM and the DVL (''[[Deutsche Versuchsanstalt für Luftfahrt]]'' – German Aviation Research Institute) eventually concluded that the Delta series was not only dangerous, but an aeronautical dead end. Only Georgii's continued support prevented them from ordering the discontinuation of the research.

The aircraft was rebuilt again, this time incorporating new aerodynamic refinements based on Lippisch's experiences with his recent [[Lippisch Storch X|Storch X]] [[Glider (sailplane)|glider]]. The new incarnation, dubbed '''Delta IVb''' proved to be a step in the right direction.

Success finally came with a last round of changes. The aircraft was rebuilt yet again, making the sweep of its wings less severe, and adding small, downturned fins at their tips. The fuselage was lengthened somewhat, and a small rudder was added to it. Now called the '''Delta IVc''', the result was finally what Lippisch had been looking for. In 1936, the aircraft was taken to the [[Luftwaffe]] flight-testing centre at [[Rechlin-Lärz Airfield|Rechlin]] where test pilot [[Heini Dittmar]] put it through its paces, gaining an airworthiness certificate for the type and an official RLM designation – '''DFS 39'''.

===Messerschmitt Me 163===
It proved to be an extremely stable and well-behaved design, and now attracted the interest of the RLM as the basis for a [[rocket]]-powered research aircraft. The work was kept secret and the new variant of the Delta IV referred to as ''Project X''. The airframe was to make significant use of metal construction, which was not available at the DFS, so Lippisch and ''Projekt X'' were transferred to [[Messerschmitt]]. It was redesignated the Me 163 and would eventually appear as the [[Messerschmitt Me 163 Komet]] rocket fighter.<ref> Lippisch, Alexander M. "Tailless Tailpiece". ''Air Enthusiast''. September 1972. pp.136-8, 150.</ref>

==Specifications (DFS 39d)==
[[File:KN Flyngwinggraph Lippisch DFS39 1936.jpg|thumb|Lippisch DFS 39, 1936]]
{{Aircraft specs
|ref=''Die Deutsche Luftrüstung 1933–1945 Vol.1 – AEG-Dornier'' <ref name=Nowarra>{{cite book |last=Nowarra |first=Heinz J. |title=Die Deutsche Luftrüstung 1933–1945 Vol.1 – AEG-Dornier |year=1993 |publisher=Bernard & Graefe Verlag |location=Koblenz |isbn=978-3-7637-5464-9 |language=German |pages=159–160, 244–245}}</ref>
|prime units?=met
<!--
        General characteristics
-->
|crew=2
|capacity=
|length m=5.4
|length note=
|span m=9.6
|span note=
|height m=1.8
|height note=
|wing area sqm=13.4
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=
|empty weight kg=390
|empty weight note=
|gross weight kg=
|gross weight note=
|max takeoff weight kg=600
|max takeoff weight note=
|fuel capacity={{cvt|150|L|USgal impgal}} fuel; {{cvt|16|L|USgal impgal}} oil
|more general=
<!--
        Powerplant
-->
|eng1 number=1
|eng1 name=[[Pobjoy R]]
|eng1 type=7-cylinder air-cooled geared radial piston engine
|eng1 hp=
|eng1 note={{cvt|85|PS|hp kW}}

|prop blade number=2
|prop name=wooden fixed-pitch propeller
|prop dia m=2.1
|prop dia note=
<!--
        Performance
-->
|max speed kmh=220
|max speed note=at sea level
|cruise speed kmh=180
|cruise speed note=<br/>
*'''Landing speed:'''{{cvt|70|km/h|mph kn}}
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|range km=1350
|range note=
|combat range km=
|combat range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=6300
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=5.8
|climb rate note=
|time to altitude={{cvt|1000|m}} in 3 minutes
|wing loading kg/m2=
|wing loading note=
|fuel consumption kg/km=
|power/mass=
|more performance=
}}

==References==
{{Reflist}}

==External links==
{{commons category|Lippisch aircraft}}
{{commons category|Fieseler F 3 Wespe}}
*[http://www.wehrmacht-history.com/luftwaffe/prototypes/dfs-39-prototype.html DFS 39 prototype] – Wehrmacht History

{{DFS aircraft}}
{{RLM aircraft designations}}
{{Lippisch aircraft}}

{{DEFAULTSORT:Lippisch Delta Iv}}
[[Category:1930s German experimental aircraft]]
[[Category:Tailless aircraft]]
[[Category:Lippisch aircraft|Delta IV]]
[[Category:Single-engined tractor aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1936]]