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Full text of "Diary of trip to California March 8-31, 1947"

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4 Waihington Place, New York 3, N, Y 

Diary of Trip to r.'sllforrla > Farch 8 - 31, 1947 

Harold Grad 

Aerojet Corporation, Aguaa 

The nroblorns of Irref^ular burning and genoral hydro- 
dynawlc flow inside iiiultlplTf connected hollow tube rockets 
were r^lscussed with T*. ^. D, Geckler and A, L. Antonio, 

Secondary peak end Irregular burning phenoirena similar 
to those observed at California Institute of Technology 
durlnf? the war have been observed In both the hollow grain 
and the rod end tube dealpns used by Aerojet. 

T' ' " • 

The Interrupted burning techniques used are still beln/a? 
developed, but from a discussion of results already available 
it appears probable that the resonance burning hypothesis 
set forth by the New York TTniverslty group Is correct. The 
physical basis of the phenonenon together with the qualitative 
effects of various rocket design features were discussed. 


Ir ordei* to verify certain aspects of the theory which h«a 
been develot)ed. It waa decided to Derforro exioerlTnenta on 
rockets of varying georretry and type of powder. Experiments 
involving direct observation of powder reaction rates and 
flow patterns Inalde the rocket are not feasible at present. 
According to "Dr. Geekler, it would be v/orthwhlle to reduce 
the irathematlcal solution to a forrri whereby the incidence of 
pressure peaks and irregular burning could be predicted in 
tenns of one or more parameters Involving the rocket eeometry 
and powder grain constants. 

In addition to the resonance burning oroblem, work done 
at New York TTnlverslty on flow In multiple channel rockets 
and on the validity of one dinenslonal treatments wts dis- 

T>r. Oeekler was also interested In heat +-ran8fer with 
variable coefficients, and requested inforrration on the work 
done by and under t^. ivacnonald on this subject. 

Some problerrs in nozzle flow were discussed with 
R. Gordon, in particular the calculation of thrust for an 
inexact exnanslon nozzle. A Tremorenduin on this subject will 
be sent to hire by Hew York TTniveraity. 

■pjxperlTnents are being perforrred on rockets which have 
purely diverging noszlea (i.e. no converging entry section), 
ra^oek reflection natterns in the exhavist can be observed 
directly by eye, since the various regions in the exhaust are 
distinctively colored. 

Several probleins involving straipjit pipe ^et wotors were 
discussed with T5r. F, ?^Brlcl<T, who was interested in a Tnemo- 
randuK being written on this subject, and who suggested so^e 
possible lines of further development. He also expressed 
interest in a renort on the Pulse Jet by Wae Donald and sehaaf 
and requested a cony. 


Dp. Tlwlcky, as well sa nun^erous other poraona encountered 
In California, la e8«j;erly airaltlng the oppearanoe of the revised 
Shook ?'eve I'nnual. 

JPL-APL Sym-posluw 

JPL - Jet Propulsion Laboratory - California Institute of 


APL - Applied Physics Laboratory - Johns Hopkins University 

The sympositur consisted mainly of a discussion of free 
fli^t techniques and comparison with wind tunnel results. 
It appears that there ere no results at present which allow 
of direct coTTparlaon between the two rrethods. 

Certain anor.alouc droft effects are observed at transsonlc 
speeds, but different experiments vary widely in results. 

k novel method of measuring drag of a projectile in free 
fll^t using a so-called belllstlc pendulum was described. 

California Institute of Technology 

Dr. Hans LleTrann was consulted on his work on interactions 
between shock and viscous boundary layers. It appears that 
the very large velocity -radients in the neighborhood of a 
viscous boundary layer at a well produce shock reflection 
patterns which are entirely different froni what la predicted 
by simple ehock reflection theory, but it is expected that 
at sufficiently large distances from the wall the pattern may 
apTwoxlciate that of the slinple theory. Slmiler curved shock 
effects are found in I^ach reflectiona because of the large 
velocity gradients In the sllpstresn. These effects, together 
with Kiore complicated shock and boundary layer phenomena are 
found to be essential in describing transsonlc flow around an 
airfoil (which may be somewhat connected v'lth recent investigations 
In New York University). 


Some proT?«rtle8 of llrit lines were discussed by 
Drs. Liepmerm and Cleuser at s lecture by the latter* 

Several Interesting probler.s eoncernlnf^ characteristics 
of hydrodynarnlc equations (with and without either heat 
conduction or viscosity); characteristics of lower order 
terms in parabolic equations; a comDarlaon of the equations 
of transient nozzle flow and waves on sloping beaches; 
some features of the Karwan-Moore perturbation method, end 
«n equation of rlxed elllr^tlc-hyperbolic character were 
dlacussed with Dr» D© Prima, 

Two water tunnels (one for rreasurenent of drag, lift, 
moment and one with a free surface at arbitrary air pressure), 
a centrifugal tornedo impact tank, and the tranasonic wind 
tunnel were visited. 

Other presons contacted on various matters are Professors 

Epstein and Bohnenblust, 

Autoratlc Computing? I'achines 

At California Institute of Technology Professor MeCann 
of the Electrical Engineering Department was consulted about 
the status of various computation developments on the coast, 
TTe is at present constructing an analogue differential analyzer, 
aimed principally at elastic beam and electrical system 
stability nroblerrs, which treats on the order of 100 linear 
ordinary differential eouations and some 10-20 nonlinear 
equations. There is a nosslbillty of a digital computer being 
constructed at California Institute of Tech-nology some time 
in the future. Various electromechanical simulators such as 
for torpedoes, guided missiles, etc. exist, and UCLA has a 
GE differential analyzer. 

Howard Hughes Aircraft is eonstrwetlni? various small 
specialized machines, and one larp;e digital machine (details 
secret) which Is nresvroably to solve !"'axwell'8 Equations. 
They have obtained some computing machine men from Bell Labs. 

Prom a consensus It appears thst the Bureau of Standards 
Institute of Numerical Analysis i-vlll probably be located at 
Stanford or Berkeley. According to the outspoken S, ^aymo. 
Director of Research at Howard Hucjies, the Bureau of standards* 
methods do not offer much chance for any development in 
larf^ scale computlnp; nachlnea other then a rehash of already 
exist Ini^ machines. 

Professors Spencer and Polya who were cortacted at 
Stanford are anxious to have the Bureau of Standards' Computing 
Center either there or at Berkeley. 

!5r. spencer has some problems on schllcht functions 
which involve large scale computations and for which he la 
thinking of usin^ the ?^iac. 

The nroblem of Ir.pact of a cone in water v;hlch is being 
put Into final form by Drs. Spencer and Shlffman was discussed, 
end some necessary liaison between the two was arranged. 




4 W»Ai.g;an Place,'i^^ York 3, N, Y