April 2, 1945
Dr. Roger Adams
1703 - 32nd Street NW
Washington 25, D.C.
I am glad to make a statement, in answer to your letter of March 29, about the matter of research in interior ballistics.
The statement made by the Army and inclosed [sic] in your letter reads as follows:
"Problem 2 a. Interior Ballistics. The complex and difficult field of interior ballistic sis one where the best of scientific talent and methods can be profitably employed. Certain specific lines of investigation are indicated in this problem, and may be amplified as follows. Studies in powder composition indicate that erratic pressures can be eliminated, and smooth pressure - time curves obtained, by the addition of certain catalysts to the powder. Various potassium salts have given promising results, but the investigation should be continued and extended to other metals. Further research is desirable in the rate of burning, in the surface temperature of burning powder, and in the composition of gases found in the early stages of nitrocellulose decomposition."
It is my opinion that the problems mentioned in this statement are worthy of attention by the Research Board for National Security. I feel, however, that there are many other problems dealing with interior ballistics which are still more important, and which should be given very thorough attention, for the sake of the security of the Nation. The following list of fifteen problems is not exhaustive.
1. The development of cannon powders with greatly decreased flash and decreased smoke. Cordite N, which contains nitroguanidine, has very promising properties, and it might be possible to formulate flashless powders which are still better.
2. The development of cannon powders with high potential and low adiabatic flame temperature, giving the possibility of considerably increased muzzle velocity and range with decreased erosion. Very great improvement in the performance of cannon might be obtained by the formulation of powders containing nitramine explosives, such as nitroguanidine or cycolnite, or other explosives with relatively large gas volume and small heat of explosion.
3. The study of the mechanism of erosion in relation to the nature of the propellant, the nature of the gun (chromium plate, design of rifling, etc.), and the nature of the projectile (pre-engraving, etc.).
4. The development of cannon powders with low dependence of burning rate on the initial temperature of the propellant, giving decreased dispersion.
5. The study of the design of grains, including strip powder, long tubular grains, and grains of possible novel design, with respect both to performance and to ease of manufacture.
6. The study of structurally composite powders, consisting of grains composed of two or more powders of different formulation, with design such as to confer on the composite powder the desirable characteristics of each of the constituent powders.
7. The thorough investigation of possible new powder constituents, (such as DSGN, DINA, Fivonite, Cyclonite, PETH).
8. The thorough study of nitrocellulose, with reference to molecular weight and degree of nitration in relation to viscosity, the effect of blending on mechanical properties of powders, and the mechanics of plasticization and stabilization, including the search for improved platicizers and stabilizers.
9. The development of improved rocket powder for dry extrusion, especially in large grains. The powder should be superior to ballistite, cordite, and other existent rocket powders with respect to having high potential, low dependence of burning rate on ambient temperature and on operating pressure, and mechanical properties such as to permit high loading densities and the use of tubular grains without danger of break-up, eliminating the necessity of complicated granulation such as cruciform.
10. The development of an improved high potential rocket powder with small web, for use in the rocket grenade and similar weapons. The powder should be superior to the present solvent extruded stick powder with respect to its temperature and pressure coefficient, giving a wider range of operating ambient temperature, and eliminating blast.
11. The development of improved end-burning grains for assistant take off and other special uses.
12. The development of special powders with high burning rates- 5, 10, 20, 40, 80 times that of ballistite, permitting the design of rockets with very high performance. These powders could be incorporated with other powders in structurally composite propellants, in such a way as to give the structurally composite propellant the desired burning rate.
13. The search for new explosives and other substances for use in special propellants for special purposes, such as for long range missiles.
14. The study of new types of propellants and techniques of manufacturing-plastic propellant, molded propellant, cast propellant, etc., with special reference to large grains.
15. The study of igniters and other auxiliaries.
Some of this work could be done effectively in the Government arsenals and Naval powder factories, some by the powder companies, and some only by University scientists.
I believe that, in addition to the study of detailed problems in interior ballistics, a thorough investigation of certain broad questions should be made. for example, the matter of the standard Navy powder for big guns should be reconsidered. There has been essentially no change in this standard Navy powder, pyro powder, for forty years. This powder is a solvent-extruded nitrocellulose powder stabilized with disphenylamine, and usually used as multiperforated short grains. For some uses the grains are stacked by hand in a regular manner, and inclosed [sic] in powder bags. It is possible that this standard Navy powder should be replaced by a new powder, which might have higher potential, giving longer range, might have a lower erosion, give less flash and less smoke, and might be in the form of long single perforated tubes which could be stacked together easily and tied with cord. The study of the possibilities and the securing of sufficient data to permit a sound decision would probably require a ten year program.
I shall be in Washington on April 12, to attend a meeting of the Medical Advisory Committee. I shall then go to the Alleghany Ballistics Laboratory in Cumberland, Maryland for a meeting on April 13 and 14, and shall return to Washington from the 15th to the 18th, in order to attend a meeting of the Research Board for National Security on April 18. Please let me know if you would like to discuss these matters with me.