Propeller Design Workshop Part III

8/12/2019 Propeller Design Workshop Part III

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Propeller Design Workshop

Presented byDavid J. Gall

Gall [email protected]

www.PropellerDesignWorkshop.com

mailto:[email protected]

http://www.propellerdesignworkshop.com/





PROPELLER DESIGN

WORKSHOP

Theory and design of practical propellers, Part . Practical PropDesign

Practical Propeller Design



!ntrod"ction• #. Dietsi"s, $.%.&.%. T$'()* +( ) -

– The %ir Propeller, !ts /trength and &orrect/hape,0 +Translated-

• 1. Weick, $.%.&.%. T$') 2 +( )3- – % /imple 4ethod for Determining the

/trength of Propellers,0 fo"rth in a series5 T$'

) 6 thr" T$') 2• %$&' +( 63-

– %vailable Where777Practical Propeller Design



!ntrod"ction• These are the 8$9: ;eferences !<ve

1o"nd• $one of them acco"nt for the in'plane

forces ca"sed by modern high'compression internal comb"stion engines




!ntrod"ction




PRACTICAL PROPELLER

DESIGN

Outline: Theory and desi n o! "ra#ti#al "ro"ellers$

Part %&(.;eality check5 Those darn physical constraints).;eynolds= n"mber and 4ach n"mber

.What abo"t those tips7>.1rom minim"m ind"ced loss to ma?im"m efficiency5 The effect of viscosity on allthose theories6.1"selage nacelle blockage +a.k.a. A/o"rce'sink slowdownA-3.8ptim"m Propellers*.%irfoil choices2.#ow to make a proper h"b

.Proper design of p"sher props(B.Gro"nd and in'flight adC"stable pitch and constant speed props

((./tr"ct"ral re "irements().Ey ;e "est




(. Physical &onstraints• Diameter• $"mber of Elades•

#"b Thickness• Thickness of the Elank• 4achine &apacity




). ;eynolds and 4ach $"mbers• /"bsonic Propellers

– Fse ;"les'of'Th"mb or – &alc"late :o"r &ritical 4ach $"mber then – %dC"st Diameter to eep Tip /peeds Eelow

4 &;

• Transonic Propellers – /ee $%/% for Fn'D"cted 1ans, etc.

• /"personic Propellers – :es, $%/% went there, too




). ;eynolds and 4ach $"mbers












. What %bo"t Those Tips7• What do yo" have after yo" c"t off the tip7• Winglets•

#oerner Tips – &"rving Fp – &"rving Down

•

Hlliptical Tips• ;o"nd Tips• /heared0 WingtipPractical Propeller Design



>. Iiscosity• Theodorsen +and all prior- adds the

visco"s effects after the fact• That<s 8 , especially with ro"nd blade

shanks – The coefficient of drag is constant at any ;P4

• The effect of viscosity is minimal so longas the coefficient of drag isn<t too high

– +8hh, those ro"nd blade shanks are soooobadK-

– #owever, they are in the place of least harmPractical Propeller Design



6. 1"selage $acelle Elockage• 9arrabee et. al De'Pitch0 after the fact to

accommodate the red"ced inflow velocity• This loses part of the relative wind that<s

"sed in the algorithm• /o, it deviates from the Goldstein

distrib"tion




3. 8ptim"m Propellers




*. %irfoil &hoices• The Traditional %irfoil &hoices

– &lark L:< – ;%1 3 – $%&% 8ne0 series – $%&% /i?0 series – Hppler – 8thers7




*. %irfoil &hoices• &an :o" 4an"fact"re !t7• Design to What &oefficient of 9ift7•

$o /harp 9eading Hdges• Watch 8"t for Thin Trailing Hdges• Try to /tay Within a 1amily

–

Hase of Thickness /caling – Hase of Performance Prediction +4odeling- – Hase of 4an"fact"re




*. %irfoil &hoices




*. %irfoil &hoices




*. %irfoil &hoices




*. %irfoil &hoices




*. %irfoil &hoices




2. #ow to 4ake a Prop+er- #"b• 4"st &arry %99 9oads• 4"st 4ate 4echanically to Hngine

– Prop 1lange and or H?tension – 4"st Deliver Hngine Power to Propeller

• /ee /port %viation archives




2. #ow to 4ake a Prop+er- #"b


















• /ensenich Website5 Wood Propellers5!nstallation, 8peration, M 4aintenance0

• Drive 9"gs0 D8 $8T Drive the Prop• /tatic 1riction Drives the Prop• /tatic 1riction 4"st be Greater Than the

Tor "e 1orces Developed in PowerP"lses• P9F/ % 9%;GH 4%;G!$ for Prop /trikes

from 9ost H?ha"st Pipes, etc. +/ilver E"llett



. Design of P"sher Propellers• #"b Goes on Eackwards0

– &enter Eore on 1ront 1ace – Drive 9"g Eores on 1ront 1ace

• %erodynamics 4"ch 4ore Diffic"lt – $8, ! don<t want to do a partially'd"cted

channel'wing contra'rotating asymmetricalp"sher propeller with winglets

– +! might consider it if it were symmetrical-




(B. %dC"stable Pitch &onst./peed

• Disc"ssion




((. /tr"ct"ral ;e "irements• %$&'




((. /tr"ct"ral ;e "irements




















(). Ey ;e "est• %irfoils• /weep• Twist• $oise• ;esonance• 4aterials• &ontra';otating +D"al ;otation-• /hro"ded• D"ctedPractical Propeller Design



Propeller Design Workshop

David J. GallGall Aerospace

[email protected] www.PropellerDesignWorkshop.com





Documents

Propeller Design Workshop Part III