National Institute for Aviation Research performs 50-feet eVTOL battery drop test

In ear­ly Decem­ber, BETA Tech­nolo­gies part­nered with the Nation­al Insti­tute for Avi­a­tion Research (NIAR) and the FAA to con­duct a 50ft Code of Fed­er­al Reg­u­la­tions (14 CFR) fuel sys­tem crash resis­tance drop test on a full-scale bat­tery sys­tem designed for an elec­tric air­craft.

This was the first time the test was attempt­ed at this scale on a rep­re­sen­ta­tive 800V pack, which absorbed the load with no sig­nif­i­cant dam­age at the cell or pack lev­el, demon­strat­ing com­pli­ance.

The FAA may adopt this drop test require­ment as a base­line means of com­pli­ance for bat­tery sys­tems. Essen­tial­ly, this test was a mile­stone in the FAA’s research into which method­ol­o­gy to use for eval­u­at­ing the crash­wor­thi­ness of bat­tery sys­tems for elec­tric air­craft, as the 50ft drop test is a con­tender for what it will require from devel­op­ers.

The results will also help to val­i­date NIAR’s sim­u­la­tion mod­el­ling method, refin­ing it for future use by BETA and oth­ers to pro­mote safe­ty and scal­a­bil­i­ty in the indus­try.

This test was also an impor­tant step toward inform­ing the FAA cer­ti­fi­ca­tion process for the indus­try, the company’s own path to cer­ti­fi­ca­tion, and cre­at­ing a foun­da­tion that will enable var­i­ous types of bat­tery test­ing in the future.

The FAA tapped NIAR as a part­ner for addi­tion­al val­i­da­tion of means of com­pli­ance test­ing, hav­ing cre­at­ed a robust sim­u­la­tion designed to mod­el the effect of the drop test on bat­tery sys­tems at the cell and pack lev­el.

Safe­ty is inte­gral to the over­all design, devel­op­ment, and oper­a­tion of eVTOL trans­port sys­tems. This test is part of an effort to guar­an­tee the safe­ty of this new tech­nol­o­gy, as it was designed to eval­u­ate and analyse the per­for­mance of bat­tery packs that will pow­er eVTOLs dur­ing an emer­gency land­ing event.

The test was car­ried out at the new NIAR lab­o­ra­to­ry facil­i­ties at the Jer­ry Moran Cen­ter for Advanced Vir­tu­al Engi­neer­ing and Test­ing locat­ed in Wichi­ta State Uni­ver­si­ty. The test and pro­cured results will also inform the FAA’s mis­sion to define future test require­ments and min­i­mum obsta­cle clear­ance.

To guar­an­tee occu­pant safe­ty, it is nec­es­sary to eval­u­ate and analyse the per­for­mance and behav­iour of the com­plete vehi­cle, includ­ing seats, bat­ter­ies, and the sur­round­ing com­pos­ite air­frame struc­ture), dur­ing an emer­gency land­ing event.

The pri­ma­ry objec­tive of this test sim­u­la­tion study was to iden­ti­fy the struc­tur­al, ther­mal, and elec­tri­cal behav­iour of the bat­tery pack dur­ing emer­gency land­ing con­di­tions.

This was in order to pro­vide infor­ma­tion to the FAA that may be used to define future require­ments and how its per­for­mance will impact the selec­tion of com­pos­ite mate­ri­als for the con­struc­tion of an air­frame capa­ble of pro­vid­ing an ade­quate lev­el of safe­ty.

Crash­wor­thi­ness by drop test­ing is cur­rent­ly reg­u­lat­ed for fuel cells and fuel tanks. Due to the preva­lence of fuel tanks and the nov­el­ty of bat­tery sys­tems in air­craft, EASA has adopt­ed these fuel tank drop test require­ments for use with bat­tery sys­tems as a start­ing point for safe­ty and risk assess­ment.

Drop test­ing of fuel sys­tems requires a 50-foot drop of a near­ly filled fuel sys­tem onto a flat, non-deform­ing sur­face, after which the fuel sys­tem is mon­i­tored for leak­age of gas or flu­ids, as well as fire or explo­sion.

This test pro­gram and sim­u­la­tion stud­ies will pro­vide infor­ma­tion regard­ing the struc­tur­al per­for­mance of the bat­tery and eval­u­a­tion of load trans­fer into the cab­in and rest of the eVTOL com­pos­ite air­frame struc­ture.

It will eval­u­ate the ther­mal per­for­mance of the bat­tery and the risk of ther­mal run­away or explo­sion, whether ther­mal shield­ing is required, and whether cur­rent com­pos­ite mate­ri­als used for con­struct­ing the fuse­lage is accept­able for this use.

Elec­tri­cal per­for­mance of the bat­tery and risk of high-volt­age dis­charge to the sur­round­ing eVTOL struc­ture, occu­pants, or first response per­son­nel will also be eval­u­at­ed, and whether advanced mate­ri­als can be used for the cab­in floor to pro­vide shield­ing dur­ing an emer­gency land­ing.

Avatar photo

Jason Pritchard

Jason Pritchard is the Editor of eVTOL Insights. He holds a BA from Leicester's De Montfort University and has worked in Journalism and Public Relations for more than a decade. Outside of work, Jason enjoys playing and watching football and golf. He also has a keen interest in Ancient Egypt.

eVTOL Insights is part of the Industry Insights Group. Registered in the UK. Company No: 14395769