NASA Crash Tests eVTOL Concept

NASA researchers recent­ly com­plet­ed a full-scale crash test of an eVTOL con­cept vehi­cle at the Land­ing and Impact Research facil­i­ty at NASA’s Lan­g­ley Research Cen­tre in Hamp­ton, Vir­ginia.

The eVTOL was a ‘Lift+Cruise’ test arti­cle devel­oped by the Rev­o­lu­tion­ary Ver­ti­cal Left Tech­nol­o­gy (RVLT) project in anoth­er effort for NASA to advance research for the Advanced Air Mobil­i­ty (AAM) mis­sion.

NASA’s vision for AAM is to help emerg­ing avi­a­tion mar­kets safe­ly devel­op an air trans­porta­tion sys­tem that moves peo­ple and car­go between places pre­vi­ous­ly not served or under­served by avi­a­tion. Under­stand­ing how these future air­craft may act in a crash sce­nario is anoth­er key point of research.

“The test was a great suc­cess for the crash­wor­thi­ness team at Lan­g­ley,” said Justin Lit­tell, research assis­tant for Langley’s Struc­tur­al Dynam­ics Branch. “We suc­cess­ful­ly test­ed the eVTOL vehi­cle con­cept rep­re­sent­ing a six-pas­sen­ger, high wing, over­head mass, mul­ti­ple rotor vehi­cle, obtain­ing more than 200 chan­nels of data, and col­lect­ing over 20 onboard and off­board cam­era views.”

A vari­ety of exper­i­ments were includ­ed on the test arti­cle. These exper­i­ments includ­ed sev­er­al seat con­fig­u­ra­tions includ­ing a NASA ener­gy absorb­ing con­cept, var­i­ous sizes of crash test dum­mies to study the effects of the crash loads on all sizes of occu­pants, and a mod­u­lar NASA-devel­oped ener­gy-absorb­ing com­pos­ite sub­floor.

“While we are still going through the data and video, and these results are pre­lim­i­nary, we see that there are two main events that occurred dur­ing this test,” said Lit­tell.

The first event was the floor crush­ing and seat stroking. The sub­floors and ener­gy absorb­ing seats func­tioned as intend­ed and lim­it­ed the effect of the impact on the crash test dum­mies. The sec­ond was the col­lapse of the over­head struc­ture. The effect of the over­head struc­ture col­lapse on the crash test dum­mies is still being deter­mined.

For this test, an over­head-mass was designed to rep­re­sent the wing struc­ture, rotor and bat­tery. The deci­sion was made to assume that all the weight of the over­head struc­ture was over the cab­in. There are many oth­er over­head-mass con­fig­u­ra­tions which may behave dif­fer­ent­ly in a crash.

“When look­ing at crash con­di­tions for these types of vehi­cles, it’s impor­tant to note the struc­tur­al weight and dis­tri­b­u­tion that must be made when exam­in­ing a spe­cif­ic design,” said Lit­tell.

The test data will be used to refine mod­el­ling tech­niques and report­ed to the AAM com­mu­ni­ty so that it can be dis­cussed.

“Our com­pu­ta­tion­al pretest mod­els did a good job pre­dict­ing the com­pos­ite defor­ma­tion until over­head struc­tur­al fail­ure,” said Lit­tell. “How­ev­er, the com­pu­ta­tion­al mod­els did not pre­dict the over­all col­lapse as seen in the test.”

The full-scale test­ing data will be used to improve the sim­u­la­tion mod­els such that in the future, the pre­dic­tions will be more real­is­tic. The data will fur­ther be used as the basis for eval­u­at­ing poten­tial test con­di­tions and con­fig­u­ra­tions that will be used dur­ing a drop test of a sec­ond Lift+Cruise test arti­cle, ten­ta­tive­ly sched­uled for test­ing in late 2023.